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Currently, research on capacitor materials for high-temperature and power electronics focuses on achieving new record-breaking limits for dielectric properties or energy storage densities, with little regard for the stability of key parameters during operation or component reliability. While environmental conditions usually do not exceed 300 °C, the voltage ratings of capacitors are still unclear. Within this work, multilayer ceramic capacitors based on lead-free sodium bismuth titanate with AgPd inner electrodes have exhibited exceptional stability of properties and capacitance at high temperatures and voltages during operation. Despite the lack of precise requirements and limits specified by manufacturers and industry, these prototype MLCCs can help to open up the field of high-temperature and power electronics. Their extensive stability of dielectric properties allows for a rather universal application. [ABSTRACT FROM AUTHOR]

—SiC is widely used in power electronics and high-temperature devices due to its comprehensive physicochemical properties, including high thermal stability, mechanical strength, etc. In recent years, the advantages of SiC for MEMS have gradually attracted the attention of researchers. However, the development of bulk SiC technology in the field of MEMS sensors has not been reviewed, especially in the fabrication and performance of MEMS bulk SiC sensors. The purpose of this review is to summarize the development status of bulk SiC materials, processes and sensors. The existing pressure sensors, accelerometers and other sensors based on SiC are reviewed. And the possible technological innovations for bulk SiC MEMS sensors are further proposed. [ABSTRACT FROM AUTHOR]

• Anti-oxidative Ag-20 at. % Cu solid solution nanoparticles were obtained. • A dense supersaturated joints with in situ precipitates and twins were obtained. • High-temperature shear strengths were increased by 66.5% at 400 ℃. • The shear strength was increased by 97.4 % after aging at 300 ℃ for 500 h. In this work, anti-oxidative single-phase Ag-Cu supersaturated solid-solution nanoparticles (Ag-Cu SS-NPs) were synthesized by a one-step method to serve as packaging materials for high-temperature power electronics. After sintering at 250 ℃ in air, a dense supersaturated structure with nano-sized Cu precipitates and coherent twins, high shear strength over 133 MPa and low resistivity (4.35 μΩ·cm) were obtained. Notably, the supersaturated structure with nano-sized Cu precipitates enhanced the thermomechanical properties and high-temperature stability. The high-temperature shear strengths of the sintered Ag-Cu joints reached remarkable 93.5 MPa at 300 ℃. Meanwhile, the room-temperature shear strength of the sintered Ag-Cu SS-NP joints after aging at 300 ℃ for 500 h was maintained at 98.7 MPa, doubling that of the sintered Ag joints. Hence, the Ag-Cu SS-NP paste presents excellent feasibility and potential for high-temperature power electronics. [ABSTRACT FROM AUTHOR]

High-temperature compatible devices of SiC have been demonstrated in recent years. Together with a high-temperature compatible die-attach, they can form a basis for future reliable high-temperature electronics. This article presents shear strength capacity of Au-rich off-eutectic Au Ge die-attach at temperatures above the eutectic melting point. Metallized (Ni/Au) SiC dice were joined to metallized (Cu/Ni/Au) Si 3 N 4 substrates with eutectic Au Ge preforms. The joints demonstrated a significant shear strength capacity up to 410 °C (50 °C above the eutectic melting point). High-quality Au-rich off-eutectic Au Ge joints, comprising a Au Ge mixture with 8 ± 4 at.% Ge, were formed with a low bond line pressure (240 kPa). At room temperature the shear strength was measured to be approximately 140 MPa, falling to approximately 40 MPa at 410 °C. This demonstrates that off-eutectic joints might be considered for use at temperatures above the eutectic melting point. The fracture mode was mainly cohesive in the off-eutectic Au Ge layer when tested at a temperature below the eutectic melting point. Above the eutectic melting point, the fracture mode was complex with signs of a partially melted off-eutectic Au Ge compound. Within this compound, columnar structures of the primary α phase (Au) was surrounded by an apparently melted and solidified phase. In other regions, an adhesive fracture at the interface between a slightly off-eutectic compound and a GeNi layer was discovered. The microstructure was found to be inhomogeneous with large regional variations within joints. From almost pure Au, primary α phase with up to 2–3 at.% Ge, up to near eutectic Au Ge regions with an overall composition of 20–30 at.% Ge. In general, Ge was segregated into explicit domains within a primary α phase. [ABSTRACT FROM AUTHOR]

Transient liquid phase (TLP) bonding is a bonding technique that has attracted several applications in high-temperature electronics, in particular, power electronics packaging. The main advantage of TLP bonding in microelectronics manufacturing is that it can be processed at a low temperature while remaining stable at relatively higher temperature. However, void formation is reported to be one of the major drawbacks in this bonding technique due to deteriorating effects of voids on shear strength and long-term reliability of TLP bonded joints. This review helps future studies to distinguish the causes of void formation in various materials that are used in TLP bonding. It will also help select the suitable solution to prevent the formation of voids and consequently improve the reliability of the TLP joint. [ABSTRACT FROM AUTHOR]

Highlights • Reactions of many fission product (FP) species with SiC are energetically favorable. • Reactions are diffusion limited, thus not expected for normal SiC-CMC applications. • SiC quality and microstructure impacts interactions with FP species. • Complexity in the LWR fuel system must be considered to predict SiC-CMC performance. Abstract Silicon carbide (SiC) fiber reinforced SiC ceramic matrix composites (CMC) represent an alternative cladding material for accident tolerant fuel light water reactor (LWR) applications, however, data and technology gaps exist that need to be understood before SiC-CMCs can be considered. One technology gap is the understanding of fuel-clad chemical interactions (FCCI) in SiC-CMC clad LWR systems. A review of SiC interactions with relevant elements to the LWR fuel system is discussed. Insights are drawn from research focusing on the use of SiC for high temperature electronics applications and high temperature structural materials applications as well as insights from tristructural-isotropic (TRISO) coated particle fuel development, where SiC is a critical component of the TRISO design. The interactions discussed in this review are framed relative to the expected conditions for SiC-CMC cladding application. The general observation is that limited risk of FCCI exists under normal operating conditions for SiC-CMC cladding systems in LWR applications. [ABSTRACT FROM AUTHOR]

Abstract This study demonstrates the reliability of SiC chip attachment sintered by nano-Ag paste during high temperature storage (HTS) tests in air at 350 °C, which was twice as high as the maximum junction temperature in service of the Si chip. The failure mechanisms of die attachment at high temperatures were diffusion and oxidation. The residual organics in the Ag paste was enough to provide the oxygen to form the continuous NiO layer at the bondline/SiC chip interface, and the oxide growth obeyed a parabolic rate law. Based on the microstructural evaluation and interfacial diffusion behavior of die attachment during HTS, the electroplated Ag layer was designed and applied on the ENIG finish as a diffusion barrier. The results showed that the die attached on the electroplated Ag substrate could support more than 800 h during HTS at 350 °C in air, which was doubled the reliability of the ENIG finished substrate. Graphical abstract Unlabelled Image Highlights • The reliability of SiC die attachment sintered by nano-Ag paste during high temperature storage at 350 °C was evaluated. • The failure mechanisms of die attachment at high temperatures were diffusion and oxidation. • The ENIG finished substrate does not support the die attachment at high temperature applications. • The electroplated Ag layer was designed as a diffusion barrier and could improve the reliability. [ABSTRACT FROM AUTHOR]

Highlights • A solar thermochemical cycle based on GeO 2 /Ge is proposed for syngas production. • CH 4 :GeO 2 ratio of 2 is beneficial for producing nonvolatile Ge. • H 2 O:Ge ratio of 8:1 is found abundant enough to ensure complete recovery of Ge. • Isothermal and nonisothermal solar thermochemical cycles are compared. Abstract Encouraged by recent advances in solar-chemical fuel production, a moderately high-temperature solar thermochemical cycle based on GeO 2 /Ge is investigated thermodynamically. Since the GeO 2 /Ge redox has a great oxygen exchange capacity and suffers unfavorable phase change at high temperature, methanothermal reduction is introduced to lower the operation temperature below melting point of redox. The calculated results indicate that reduction conditions of 875 K ⩽ T red ⩽ 1200 K and CH 4 :GeO 2 = 2:1 are conducive to achieving high selectivities of H 2 and CO. As for the oxidation step, the H 2 O:Ge ratio of 8:1 is found abundant enough to ensure complete reoxidation of Ge. Isothermal and non-isothermal solar-to-fuel efficiency ( η solar - fuel ) are compared, where R oxi = 2 and R oxi = 8 are suggested to pursue highest non-isothermal η solar - fuel of 0.47 and isothermal η solar - fuel of 0.28 respectively. In addition, the preferred site of CH 4 adsorbing on GeO 2 is predicted, and the calculated adsorption energy is lower than that of SnO 2 , indicating that GeO 2 could be a suitable material for substrate before methanothermal reduction. [ABSTRACT FROM AUTHOR]

Abstract Metal nanostructure arrays have been progressed as an alternative to the conventional oxides-based transparent conductive electrodes. Herein, we demonstrate the improved reliability of silver nanowire (AgNW) electrodes by photoresist encapsulation. The incorporation of photoresist followed by photolithography is beneficial to selectively pattern the AgNWs on poly[ether sulfone]. By varying the development or removal time of the ultraviolet (UV)-exposed photoresist, the properties of the AgNWs in the electrode are significantly varied. The optical parameters such as transmittance, haziness, and the yellow index of the electrodes have been extensively studied to reveal the advantage of the selective photoresist patterning. The AgNW electrodes patterned under 120 s of development time explored superior optical and electrical properties with high durability. The electrical properties of the AgNW electrodes at high temperatures (250 °C) demonstrate the photoresist-induced stability as compared to bare samples. Further, the morphological examination after the high temperature treatment reveals the reduced Rayleigh instability effects in 120 s developed AgNWs that facilitate the reliability under harsh conditions. Graphical abstract Unlabelled Image Highlights • Selective passivation of AgNWs electrode achieved with a photoresist. • Haze/yellow index variation of AgNW electrode with various developing time revealed. • AgNW passivated with 120 s developing time show high reliability until 250 °C. • Selective passivation of AgNWs suppressed thermally induced Rayleigh instability. [ABSTRACT FROM AUTHOR]

Coated fuel particle (CFP) is one of important factors attributing to the inherent safety feature of high temperature engineering test reactor (HTTR). However, the random arrangement of CFPs makes the simulation more complicated, becoming one of the factors affects the accuracy of the HTTR criticality calculations. In this study, an explicit random model for CFPs arrangement, namely realized random packing (RRP), was developed for the whole core of HTTR using a Monte-Carlo MCNP6 code. The effect of random placement of CFPs was investigated by making a comparison between the RRP and conventional uniform models. The results showed that the RRP model gave a lower excess reactivity than that of the uniform model, and the more number of fuel columns loading into the core, the greater the difference in excess reactivity between the RRP and uniform models. For example, the difference in excess reactivity increased from 0.07 to 0.17 %Δk/k when the number of fuel column increased from 9 to 30. Regarding the control rods position prediction, the RRP showed the results, which were closer to experiment than the uniform model. In addition, the difference in control rods position between the RRP and uniform models also increases from 12 to 17 mm as increasing number of fuel columns from 19 to 30. [ABSTRACT FROM AUTHOR]

In this paper, heteroepitaxy of Ga 2 O 3 film was performed by MOCVD on (001)-oriented mica substrates, and pure (2 ‾ 01)-oriented beta-Ga 2 O 3 films were obtained. Based on the prepared Ga 2 O 3 film, horizontal structured Schottky barrier photodetectors were fabricated. The device exhibited self-powered capability, achieving a responsivity of 21 mA/W, a photo-to-dark current ratio of 103 and a detectivity of 1.2 × 1012 Jones at 0 V. A high response speed with a relaxation time superior to 0.1s was obtained. In addition, the device showed good flexibility and maintained the pre-bending performance in the bending state. This shows the promise of mica substrates and MOCVD in high-temperature flexible electronics. [ABSTRACT FROM AUTHOR]

The high-temperature and high-humidity storage behaviors and electrochemical degradation mechanism of LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode material are investigated systematically. After stored at 55 °C and 80% relative humidity, three kinds of changes are observed compared to the fresh materials. The first change is adsorbed species on the surface of the materials caused by atmospheric H 2 O and CO 2 . The second is a layer of impurities consisting of LiOH and Li 2 CO 3 coated on the surface of the materials non-uniformly. The third is a delithiation layer directly contacting with the bulk materials in the near-surface region, which is believed to be formed by lithium-ions migrating out from the lattice accompanied by the generation of the impurities. A different combination of heating temperature, heating time and heating atmosphere is performed to achieve the separation of the adsorbed species and the delithiation layer (together with the impurities) and study the role of different part in electrochemical degradation, respectively. For the first and the following cycles, the effect of the adsorbed species on the electrochemical properties takes a larger proportion than that of the delithiation layer and impurities. [ABSTRACT FROM AUTHOR]

Ion-conducting memristors comprised of the layered chalcogenide materials Ge 2 Se 3 /SnSe/Ag are described. The memristor, termed a self-directed channel (SDC) device, can be classified as a generic memristor and can tolerate continuous high temperature operation (at least 150 °C). Unlike other chalcogenide-based ion conducting device types, the SDC device does not require complicated fabrication steps, such as photodoping or thermal annealing, making these devices faster and more reliable to fabricate. Device pulsed response shows fast state switching in the 10 −9 s range. Device cycling at both room temperature and 140 °C show write endurance of at least 1 billion. [ABSTRACT FROM AUTHOR]

The temperature dependent ion conductivity of yttria stabilized zirconia (YSZ) can be used to create a miniaturized flow sensor using a calorimetric measurement scheme. Such a sensor is compatible with harsh environments, and can sustain temperatures of up to 1000 °C, although thermal crosstalk will limit its performance as the temperature rises. This paper investigates if the integration of thermal isolation in the form of sealed cavities can mitigate the detrimental effect of the thermal crosstalk, particularly by studying the conditioning time of the sensor to temperature changes. To this end, high temperature co-fired ceramic (HTCC) sensors were fabricated from tapes of 8 mol-% YSZ that were screen printed with platinum paste. Definition of channels and structures were made by milling the green tapes, and sacrificial inserts were placed in all cavities to give mechanical support during lamination and sintering. Cavities with widths of 240 μm, 400 μm and 560 μm were investigated, and sensors without cavities were also made to serve as references. Additionally, two different positions of the sensor element with respect to the edge of the cavity (560 or 800 μm) were investigated. The results showed that it was possible to improve the conditioning time of the sensor by up to five times by the use of isolating cavities, and that this improvement is translated into a reduction in rate-dependent hysteresis for measurements with long elapse times. The latter effect is most pronounced for the sensors with the largest cavities. [ABSTRACT FROM AUTHOR]

SiC is a wide bandgap semiconductor with better electrothermal properties than silicon, including higher temperature of operation, higher breakdown voltage, lower losses and the ability to switch at higher frequencies. However, the power cycling performance of SiC devices in traditional silicon packaging systems is in need of further investigation since initial studies have shown reduced reliability. These traditional packaging systems have been developed for silicon, a semiconductor with different electrothermal and thermomechanical properties from SiC, hence the stresses on the different components of the package will change. Pressure packages, a packaging alternative where the weak elements of the traditional systems like wirebonds are removed, have demonstrated enhanced reliability for silicon devices however, there has not been much investigation on the performance of SiC devices in press-pack assemblies. This will be important for high power applications where reliability is critical. In this paper, SiC Schottky diodes in pressure packages have been evaluated, including the electrothermal characterisation for different clamping forces and contact materials, the thermal impedance evaluation and initial thermal cycling studies, focusing on the use of aluminium graphite as contact material. [ABSTRACT FROM AUTHOR]

Off-centre operation of high-temperature superconducting (HTS) maglev systems caused by inevitable conditions such as the misregistration of vehicle, crosswind and curve negotiation, may change the distribution of the trapped flux in the HTS bulks and the magnetic interaction between HTS bulks and the PMG. It impacts on the performance of HTS maglev, and more seriously makes the maglev vehicle overturned. Therefore, understanding the performance of the HTS maglev in off-center operation is very important. In this paper, the dynamic response characteristics of a cryostat with twenty-four onboard YBaCuO superconductor bulks were experimentally investigated at different eccentric distances under loads before the initial FC process. Parameters such as vibration accelerations, displacement, natural frequency and dynamic stiffness were acquired and analyzed via the B&K vibration analyzer and laser displacement sensors. Results suggest that the natural frequency and dynamic stiffness of the maglev vehicle would be obviously reduced with the eccentric distance, posing negative effects on the stability of HTS maglev. [ABSTRACT FROM AUTHOR]

During the exploration of underground energy such as oil and gas and the application of geothermal energy, more deep drilling wells are developed. To meet the increasingly multifunctional demand of downhole equipment, many high-temperature sensitive electronics should be integrated and operate under deep downhole environment at the temperature over 200 °C. In this regard, the application of cost-effective thermal management strategies for the electronics is critical to ensuring the stable and reliable operation of downhole tools. This paper presents a review on applicable thermal management systems (TMSs) of electronics operating under deep downhole environment. Firstly, the structural characteristics, thermal performance and applicable restrictions of active and passive thermal management strategies used for downhole devices are detailly discussed. The merits and demerits of various TMS are also summarized. Meanwhile, due to the high heat flux transferred from the external environment, reviews on the thermal insulation shielding are also emphasized. As a result, the thermal management methods are divided into two categories based on the heat sources and heat dissipation terminals. Meanwhile, future developments of various thermal management approaches are discussed, aiming to serve as a reference guide for engineers and promote the progress of the next-generation equipment TMS in downhole environment. [ABSTRACT FROM AUTHOR]

Diamond and cubic polymorph of boron nitride (c-BN) are two promising next-generation ultrawide bandgap semiconductor materials owning superior thermal properties. Although lattice vibration is the dominant mechanism of heat conduction in semiconductors, electron-phonon interactions exist and may affect phonon transport in doped semiconductors; yet such effects in wide bandgap materials have not received much attention. In this study, we explore the effects of electron-phonon interactions on the lattice thermal conductivity and phonon transport in n-doped Si, diamond, and c-BN under various electron concentrations and in a wide temperature range from 300 K to 900 K based on the first-principles calculation. It is found that the electron-phonon interactions will bring down the thermal conductivity of doped materials, and the depletion impact increases as the electron concentration increases but decreases as the temperature increases. This depression effect in ultrawide bandgap diamond and c-BN is apparent, though it is not as severe as in Si. At room temperature with a high electron concentration of 1021 cm−3, the reduction of thermal conductivity reaches 36 % in Si, and 17.4 % and 16.1 % in diamond and c-BN, respectively. [Display omitted] • Thermal effect of electron-phonon interactions in doped c-BN and diamond is revealed. • Temperature and electron concentration dependent lattice thermal conductivity is quantified. • Thermal depletions exist in doped c-BN and diamond, but not as severe as in doped Si. • Depletion lessens as temperature rises, but increases with increasing electron concentration. • Ultrawide bandgap materials have great potentials in high-power high-temperature electronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new anisotropic microcomposite (AMC) joint utilizing a lotus-type porous Cu (LPC) sheet and Sn-based solder was developed. • A simple reflow process allowed joint formation via infiltration of the molten solder into the LPC sheet. • AMC joints exhibited thermal conductivity of 142.4 W/m·K, 2.5 times higher than that of the solder. • A stable shear strength of > 46 MPa was achieved after the aging test at 200 °C for 1008 h. • LPC utilization exploited the full potential of the solder for high-temperature electronic applications. The miniaturization of power conversion systems requires high-power density operation of power modules, causing the heat-density increase. Therefore, it is essential to develop bonding technology to realize highly thermally conductive and reliable high-temperature joints. In this study, we propose a novel anisotropic microcomposite (AMC) joint that integrates a lotus-type porous Cu (LPC) sheet and Sn-based solder for high-temperature electronic applications. The AMC joint was successfully fabricated by infiltrating the molten solder into the unidirectional pores of the LPC sheet during a simple reflow process. Steady-state thermal conductivity measurements for a uniquely designed specimen revealed its equivalent thermal conductivity (142.4 W/m·K), 2.5 times higher than the solder. Finite element simulations supported its excellent thermal performance by investigating the heat flux distribution and thermal conductivity prediction that utilize a three-dimensional image-based constructed model. In addition, the aging test at 200 °C for 1008 h clarified a stable shear strength of over 46 MPa. This indicates a reliable mechanical performance at 200 °C, which is only 20 °C below the melting point of the solder. These experimental and numerical studies proved the potential of the novel joint as a high-temperature electronics joint and offered possible mechanisms for its thermal and mechanical property enhancement. [ABSTRACT FROM AUTHOR]

The micro-thermophotovoltaic (TPV) power generator is an important solid-state energy conversion system which utilizes high-temperature photons to generate electricity by the photovoltaics effect. Micro-combustor is an important component in this system. In order to obtain high system efficiency, a micro-combustor with high-temperature, high-uniformity and high-efficiency is strongly desired. Here we report a micro planar combustor with the desired features. The planar combustor is fabricated with two numerically optimized baffles which form a heat recirculation chamber. The thermal energy of the hot reacting gas could be utilized to preheat the fresh gas. The performances of the combustor under various operating conditions are investigated experimentally. Numerical simulation is performed to identify the flow field and mass fraction distribution in the planar combustor. A peak combustor wall temperature as high as 1354 K is achieved with superior uniformity. By incorporating the designed micro planar combustor into the micro-TPV system, a system efficiency of 4.1% could be obtained. This system efficiency is twice higher than the system with only conventional planar combustor. As a result, the development of the planar combustor with baffles could pave a way to the development of high-performance of the micro-TPV system. [ABSTRACT FROM AUTHOR]

This paper presents a finite element model based on the H -formulation to solve the electromagnetic behavior and AC loss in rectangular bulk superconductor with an elliptical flaw in AC external field condition. Both the interior flaw and the edge flaw are considered. A modified E – J power law which is valid for an arbitrary current density range is adopted in order to predict the strong local enhancement of the current density in the vicinity of the flaw tip. The results for the usual E – J power law are calculated for comparison as well. The simulation results show that the existence of the flaw significantly blocks the flow of the induced current and forces the current to redistribute around it. Meanwhile, the strong local enhancement of the current density is observed in the vicinity of the flaw tip. Furthermore, the influences of the size and position of the flaw on the local enhancement of the current density in the vicinity of the flaw tip are investigated. In addition, it is found that the influence of the flaw on the AC loss of the sample is slight for both cases of the interior flaw and the edge flaw. [ABSTRACT FROM AUTHOR]

SiC has attracted much interest due to its vast applications in high power, high frequency and radiation-hardened electronics at high temperatures. Although the growth and processing technology for SiC wafers has matured, scratches created during surface preparation will unavoidably deteriorate both device performances and the quality of materials which are fabricated on it. Hydrogen etching has been proposed as an effective approach to obtain ideal SiC surfaces with large atomically flat steps. Here, we reported a systematical investigation on the effects of processing parameters to the hydrogen etching of 4H–SiC (0001). Accordingly, a new two-step etching method was developed with a specifically designed crucible to take advantage of the found correlation between those parameters and the terrace features. The method demonstrates high efficiency to realize atomically uniform SiC surface morphology with more than 70% coverage of the sample surface. It offers a possible route for large scale industrial SiC wafer planarization. [ABSTRACT FROM AUTHOR]

Power electronics packages typically comprise a dielectric substrate bonded to a metal layer and attached to heat sinks using a low-thermal-conductivity solder. These multiple layers increase the effective thermal resistance of the package and are responsible for package failures under cyclic thermal loads. Bonding the aluminum nitride dielectric layer (AlN) directly to a low coefficient of thermal expansion (CTE) aluminum silicon carbide (AlSiC) cold plate using copper‑aluminum (Cu-Al) transient liquid phase (TLP) bonding has been shown to improve the mechanical reliability of the power electronic packages while making the package more compact by bringing the cooling solutions closer to the devices. This study aims to characterize the Cu-Al bonds formed during the TLP bonding of AlSiC with three different power electronics substrates: pure aluminum nitride (AlN), aluminum (DBA), and copper (DBC). The material compositions and microstructures of the bonds were analyzed using scanning electron microscopy (SEM), x-ray spectroscopy (EDS), confocal scanning acoustic microscopy (C-SAM), and x-ray diffraction (XRD). α-Al solid compound was identified as the dominant phase in AlN-AlSiC and Al-AlSiC, with a notable presence of SiC particles. In contrast, three intermetallic phases – θ-CuAl 2 , η-CuAl, and γ′- Cu 9 Al 4 – were observed in the Cu-AlSiC bond. A computational solid-state diffusion model was developed to predict the intermetallic compounds (IMCs) formed during Cu-Al TLP bonding in each system, which supported the observation that an initial Cu volume fraction of 20 % in the material layers produced a final bond composition of >95 % Al with minimal IMC growth. However, increased Cu concentrations produced higher concentration gradients, leading to increased growth of IMCs, Kirkendall voids, and interstitial cracks. • Transient liquid phase bonding of AlN to AlSiC compacts power modules stack • Lower CTE mismatch enhances thermomechanical reliability. • Bonding technique is useful to attach commercial substrates to heat sinks. • Formation of intermetallic compounds increases crack development in the bond layer. • Diffusion model can aid in determination of intermetallic compounds formed. [ABSTRACT FROM AUTHOR]

Temperature measurements inside semi-transparent materials are important in many fields. This study investigates the measurements of interior temperature distributions in a one-dimensional semi-transparent material using multi-wavelength pyrometry based on the Levenberg-Marquardt method (LMM). The investigated material is semi-transparent Zinc Sulfide (ZnS), an infrared-transmitting optical material operating at long wavelengths. The radiation properties of the one-dimensional semi-transparent ZnS plate, including the effective spectral-directional radiation intensity and the proportion of emitted radiation, are numerically discussed at different wavelengths (8.0-14.0µm) and temperature distributions (400-800K) to provide the basic data for the temperature inversion problem. Multi-wavelength pyrometry was combined with the Levenberg-Marquardt method to resolve the temperature distribution along the radiative transfer direction based on the line-of-sight spectral radiation intensities at multiple wavelengths in the optimized spectral range of (11.0-14.0µm) for the semi-transparent ZnS plate. The analyses of the non-linear inverse problem show that with less than 5.0% noise, the inversion temperature results using the Levenberg-Marquardt method are satisfactory for linear or Gaussian temperature distributions in actual applications. The analysis provides valuable guidelines for applications using multi-wavelength pyrometry for temperature measurements of semi-transparent materials. [ABSTRACT FROM AUTHOR]

Abstract: Attempt to achieve a surface passivation of p-type GaN was conducted on low-Mg-doped p-GaN by employing SiN films depositions by an Ar-plasma-sputtering and a plasma-enhancement chemical vapor deposition. Process induced damages were then characterized by using a high-temperature isothermal capacitance transient spectroscopy. A large single peak, likely attributed to acceptor-type surface states, was detected in the as-grown samples. The energy level was measured to be 1.18eV above the valence band edge, which is close to a Ga-vacancy (VGa) reported elsewhere. It was suggested that a small portion of Ga atoms were missing from the surface, and a large density of VGa were created in a few surface layers. The peak intensity was found to significantly decrease by the SiN depositions, irrespective of the deposition methods, and further decreases upon annealing at 800°C. After the SiN deposition and the annealing, the peak intensity decreased: the pure Ga vacancies may transform into complex defects in the course of the SiN deposition and annealing. These results show that the present characterization method with the low-Mg-doped p-GaN Schottky contacts is effective and serves as sensitive characterization of the surface defects. [Copyright &y& Elsevier]

Abstract: Y1−x Ca x BaCo4O7 (0.0≤x≤1.0) samples were prepared by the solid-state reaction method and their high-temperature electronic transport properties were investigated in nitrogen and oxygen respectively. Phase structure of Y1−x Ca x BaCo4O7 transforms from hexagonal symmetry for x ≤0.6 samples to orthorhombic symmetry for x≥0.8 samples. In nitrogen, Y1−x Ca x BaCo4O7 samples evolve three kinds of electronic transport behaviors with the increase of Ca content: thermal activation conduction, small polaron hopping conduction, and a possible mixed conduction. Ca doping increases the hole concentration and thus decreases Seebeck coefficients. In oxygen, the temperature dependence of electrical resistivity and Seebeck coefficients of Y1−x Ca x BaCo4O7 samples displays similar change to their respective thermogravimetric curve, showing their electronic transport behavior under the control of their oxygen adsoption/desorption process. [Copyright &y& Elsevier]

Abstract: On the basis of the models of various developed high-temperature fuel-cell heat-engine hybrid systems, a unified model of hybrid systems is proposed. General expressions for the power output and efficiency of hybrid systems, high-temperature fuel cells such as solid oxide fuel cells (SOFCs) and molten carbonate fuel cells (MCFCs), and heat engines including the Brayton, Otto, Diesel, Atkinson, Braysson, and Carnot engines are, respectively, derived by using the theories of electrochemistry and non-equilibrium thermodynamics. The effects of main irreversible losses existing in real fuel cells and heat engines on the performance of hybrid systems are investigated. The general performance characteristics and optimal operating regions of some of the key parameters of hybrid systems are discussed in detail. A variety of special typical cases are discussed. The important results in the literature can be readily reproduced, and the interesting findings of our study are presented. [Copyright &y& Elsevier]

Highlights: [•] We compare 3 die-attach technologies for high temperature power electronics packaging. [•] Micro and nano silver sintering processes and AuGe solder alloy process are presented. [•] After high thermal ageing test, the results showed very high die shear strenght capability. [•] No evolution of the AuGe solder alloy joint is observed after 2500 thermal shocks cycles. [•] High range of temperature was used for the ageing test (-55°C to +245°C). [ABSTRACT FROM AUTHOR]

Highlights: [•] Bulk Au-Ge solder’s resistivity decreases initially but saturates under 300°C aging. [•] Ge coalescences and Au experiences grain growth during thermal aging. [•] Au-Ge solder joint’s resistivity increases under 300°C thermal aging. [•] Growth of intermetallic compounds, namely NiGe and Ni5Ge3, increases with time. [•] 300°C thermal aging also led to damage of the Ni(P) layer. [ABSTRACT FROM AUTHOR]

Abstract: The visco-plastic behaviour of solder joints of two models of a flip chip FC48D6.3C457DC mounted on a printed circuit board (PCB) via SnAgCu solder is investigated using Anand''s model. While the bumps of one of the models are realistic with 6μm thickness of intermetallic compound (IMC) at interconnects of solder and bond pads, the other are made up of conventional bumps without IMC at these interconnects. The solder bump profiles were created using a combination of analytical method and construction geometry. The assembled package on PCB was accelerated thermally cycled (ATC) using IEC standard 60749-25. It was found in the result of the simulation that IMC does not only impact solder joint reliability but also is a key factor of fatigue failure of solder joints. The IMC sandwiched between bond pad at chip side and solder bulk is the most critical and its interface with solder bulk is the most vulnerable site of damage. With reference to our results, it is proposed that non inclusion of IMC in solder joint models composed of Sn-based solder and metalized copper substrate is one of the major causes of the discrepancy on solder joint fatigue life predicted using finite element modelling and the one obtained through experimental investigation. [Copyright &y& Elsevier]

• The sensor with three-layer structure was prepared by 3D printing technology. • The sensor exhibits good electrical and thermal conductivity while being flexible. • The sensor shows high temperature resistance and works stably at 250 °C. With the rapid development of the aerospace, military, electronics, electric power, automotive, and other fields, flexible sensors with high temperature resistance and good thermal conductivity are increasingly in demand. These sensors need to be highly reliable and maintain resistance to heat, humidity, and physical shock so that their terminal units can withstand extreme environments. In this context, conductive adhesives have attracted considerable interest due to their unparalleled potential for the development of high-temperature flexible sensors and power electronics. In this work, a three-layer structure containing silver nanomixes (Ag-NMs), silver microflakes (Ag-MFs), and polyimide (PI) layers was prepared for use in flexible resistive strain sensor by combining the high electrical and thermal conductivity of sintered nano-silver and the flexibility of micron silver using a 3D printing strategy. This resistive strain sensor exhibits low volume resistivity (1.37 × 10−5 Ω·cm), high thermal conductivity (39 W·m−1·K−1), high temperature resistance (capable of stable operation at 250 °C), high sensitivity (ΔR/R 0 values of up to 0.43 and 0.45 after bending to 100° at 25 °C and 250 °C, respectively; ΔR/R 0 values of up to 0.31 and 0.18 after stretching 2.5% at 25 °C and 250 °C, respectively), and low fatigue after 1000 load-unload cycles. The Ag-NMs/Ag-MFs/PI flexible resistive strain sensor effectively operates at temperatures up to 250 °C for long periods of time, showing great promise for application in harsh environments. [ABSTRACT FROM AUTHOR]

Abstract: This paper will discuss the development of SiC lateral power junction field-effect transistors (JFETs) and ICs. Normally-off RESURF vertical-channel lateral power JFETs are fabricated and characterized. New results for the first demonstration of SiC Power ICs are presented and the potential for distributed DC–DC power converters at high frequencies is discussed. [Copyright &y& Elsevier]

Abstract: Silicon carbide is a promising wide-bandgap semiconductor intended for use in fabrication of high temperature, high power, and fast switching microelectronics components running without cooling. For hydrogen sensing applications, silicon carbide is generally used in conjunction with either palladium or platinum, both of them being good catalysts for hydrogen. Here we report on the temperature-dependent structural changes of silicon carbide substrates implanted with 13 keV Pt ions, providing a hydrogen-sensitive medium, and coated with W, providing electrical contacts to the device. [Copyright &y& Elsevier]

To promote solutions of key fusion problems like tritium retention and wall erosion, more measured data of carbon deposition in remote areas of fusion devices are needed. These data are essential to understand and model local and global particle fluxes and to make predictions for future devices like ITER. In spring 2000 the development of a new diagnostic, quartz microbalance (QMB), was started to measure quantitatively, in situ and time resolved (≤1 s) the material deposition in the sub divertor region of JET. Calibration work of mass and temperature characteristic was done at FZ-Jülich giving a layer mass sensitivity of Γmass=7.5×10-9 g/Hz and a temperature sensitivity of Γtemp(100 °C)≉0.09 °C/Hz. The commercially available QMB technique was adapted to the harsh constraints and requirements of JET. After implementation in March 2002 reliable and successful operation was demonstrated during the C5 campaign (∼1000 plasma pulses). First examples of measurements are presented. [Copyright &y& Elsevier]

We evaluate the usefulness of partially depleted SOI CMOS devices fabricated in a 0.35 μm technology on UNIBOND material for electronics applications requiring robust operation under extreme environment conditions consisting of low and/or high temperature, and under substantial radiation exposure. The threshold voltage, effective mobility, and the impact ionization parameters were determined across temperature for both the nFETs and the pFETs. The radiation response was characterized using threshold voltage shifts of both the front-gate and back-gate transistors. These results suggest that this 0.35 μm partially depleted SOI CMOS technology is suitable for operation across a wide range of extreme environment conditions consisting of: cryogenic temperatures down to 86 K, elevated temperatures up to 573 K, and under radiation exposure to 1.3 Mrad(Si) total dose. [Copyright &y& Elsevier]

• A novel of high ductility Mo-2.5 wt% ZrTiO 4 alloy was design. • Ductility reaches the maximum at 2.5 wt% ZrTiO 4 and the room temperature elongation is 25.4% • Mo-ZT alloy strength increases with higher ZrTiO 4 secondary phase content. • The main mechanism of ductility improvement is small-sized sub-crystals are not formed in the molybdenum matrix. Molybdenum materials are widely used in electronics and high-temperature applications because of their high strength and recrystallization temperature, good electrical and thermal conductivity. However, molybdenum brittleness, low ductility, and fracture toughness have been limiting its applications. In this work, a new Mo-ZT (Mo-ZrTiO 4) alloy was designed containing various amounts of the ZrTiO 4 secondary phase, ranging from 0.5 wt% to 3 wt%. The Mo-ZT alloy with 2.5 wt% ZrTiO 4 has the ultimate tensile strength above 1,000 MPa(rolled) and 25% elongation (annealed), which is higher than previously reported molybdenum alloys. Compared with the Mo-1ZT alloy, the elongation is increased by 166% with 2.5 wt% ZrTiO 4 addition. This offers novel insights for improving alloys' ductility. [ABSTRACT FROM AUTHOR]

• Microstructural and mechanical stabilities of 30Ni-70Sn TLPS joints are analyzed. • The microstructures of Ni 3 Sn 4 intermetallics around Ni particles are dense and stable during aging. • The initial strengths maintained even after aging for 1000 h at 150 and 200 °C. • Ni-Sn paste is effective as a die attach material for power electronic devices. In this study, the feasibility and high-temperature stability of Ni-Sn bonded joints fabricated by transient liquid phase sintering (TLPS) were investigated for high-temperature power electronics applications. A 30Ni-70Sn (wt%) TLPS paste was fabricated with micro-sized pure Ni and Sn powders, and chip bonding was performed on a direct bonded copper (DBC) substrate. During TLPS bonding, Sn particles melted and reacted with Ni particles, which resulting in the formation of stable Ni-Sn TLPS intermetallic joints. During aging treatments at 150 and 200 °C, the formed Ni 3 Sn 4 phases were transformed into the Ni 3 Sn 2. With increasing aging treatments, the reactions between Ni 3 Sn 4 intermetallics and remaining Ni particles increased, which resulted in the formation of the Ni-rich Ni-Sn intermetallics. Even after 1000 h at an aging temperature of 200 °C, there is no significant difference in the stable and dense microstructure of Ni-Sn TLPS joints. In addition, their mechanical strengths did not vary significantly even after long-term treatment for 1000 h at 150 and 200 °C. This means that the Ni-Sn TLPS joints have a good long-term microstructural stability and mechanical reliability at high temperatures up to 200 °C. Therefore, we conclude that the Ni-Sn paste is a promising candidate as a die-attach material for high-temperature electronic assemblies. [ABSTRACT FROM AUTHOR]

As a special polymer material, poly (arylene ether nitrile) (PEN) has been widely used in commercial areas. By enhancing the crystalline properties of PEN, it is more conducive to improving its heat resistance, mechanical strength and corrosion resistance. In this paper, a crystalline PEN copolymer was synthesized with the monomers of bisphenol A, hydroquinone and dichlorobenzonitrile by random copolymerization, and the film was cast by a simple casting method. Then the crystalline PEN film was modified by isothermal heat treatment and thermal stretching method. During the heat treatment, the crystallization of the PEN film was researched, and suitable temperature conditions were found for the thermal stretching experiment. During the thermal stretching process, the bisphenol A segment increased the plasticity of the copolymer, promoted crystallization, and improved the overall performance of the copolymer film. The final sample with a stretching rate of 200% had the best overall performance with the thermal decomposition temperature of 5% mass (T d5%) of higher than 500 °C, the mechanical tensile strength of 197.6 MPa, the dielectric constant of 3.4, the dielectric loss of less than 0.02, and the crystallinity of 34.49%. Besides, the closely arranged spherulites were observed by scanning electron microscope. Therefore, this article provides a new effective way to improve the crystalline properties of the crystalline PEN, and the modified PEN copolymers have potential application value in the fields of high temperature resistance and electronics. [Display omitted] • Intra-segment plasticization of BPA improved the crystallinity of PEN. •Isothermal heat treatment provided conditions for the thermal stretching of PEN film. •Optical means qualitatively characterized the change of PEN film crystallinity. •Thermal stretching improved the overall performance of PEN film. [ABSTRACT FROM AUTHOR]

Refractory metals (titanium, molybdenum, and zirconium) with a gold overlayer were used to form ohmic contacts on {113}-oriented boron doped diamond epitaxial layers (boron concentration ranging from 1019 to 1021 cm−3). Morphology and thickness of deposited layers were determined by AFM and X-SEM; resistivity, carrier concentration and mobility were determined by Hall measurement. Specific contact resistance R Csp of evaporated Ti/Au, Zr/Au, and Mo/Au contacts was measured using c-TLM structures after different annealing stages at temperatures up to 850 °C. Results show that on layers with {113} orientation it is possible to achieve ohmic contacts of comparable quality as for layers with {100} orientation. For all three metal systems, the lowest values for specific contact resistance reached 1 × 10−6 Ω.cm2. Ti/Au contacts show a stable ohmic behavior over the whole range of annealing temperatures, while Mo/Ti contacts had to be annealed above 500 °C to reduce the Schottky barrier and achieve good ohmic contact on lower B doped layers. Zr/Au contacts exhibit the lowest adhesion and required annealing to at least 700 °C to achieve ideal electrical and mechanical properties. Mo/Au and Zr/Au contacts on highly boron doped layers (~1021 cm−3) show excellent contacts when annealed at 700 °C, and therefore can be considered as improved candidates for ohmic contacts for diamond-based high-temperature power electronics than the conventional Ti/Au (Ti/Pt/Au) contact system. In summary, this study confirms the suitability of {113} oriented boron doped diamond epitaxial layers for the fabrication of diamond power electronic devices with excellent ohmic contacts. [Display omitted] • Ti, Mo, and Zr contacts deposited on {113}-oriented BDD layers. • The lowest values for specific contact resistance reached 10−6 Ω.cm2 for all metals. • Excellent Zr and Mo ohmic contacts to highly BDD layers after annealing at 700 °C. • {113}-oriented BDD allows realization of excellent ohmic contacts for power devices. [ABSTRACT FROM AUTHOR]

Thermal stress caused by the coefficients of thermal expansion (CTE) mismatch of materials is the main failure mechanism in power electronic packaging. High junction temperature (T j) would induce larger thermal stress and accelerate failing process. In this paper, two packaging strategies to reduce thermal stress of power module for high-temperature operation were presented based on organic-free sintered Ag bonding and wireless packaging structuring: reduce elastic modulus of sintered Ag layer by changing sintering parameters; and reduce the CTE mismatch by changing the ribbon material. Finite-element analysis (FEA) simulations confirmed that these strategies can effectively reduce the maximum and average thermal stress in power electronics packaging. Furthermore, by combining these two strategies, high-temperature power cycling test indicated that the wireless packaging with Cu30Mo70 ribbon and 5 MPa sintering pressure exhibited excellent durability and reliability in the temperature swing at the junction (Δ T j ∆T j) over 150 K. • Two packaging strategies to reduce thermal stress for high-temperature operation • FEA results indicate that the maximum thermal stress would decrease by 30–55%. • The lifetime is increased to ~20,000 cycles at the temperature over 200 °C. • Strategies are applied with organic-free Ag sintering and wireless packaging. [ABSTRACT FROM AUTHOR]

Palladium coated copper (PCC) wire has been increasingly used in the semiconductor package in the last 10 years, especially in consumer products as a low-cost alternative to gold (Au) bonding wire. However, the PCC wire is still not widely used in the automotive industry due to the reliability limitations under a high temperature condition. In order to improve the long term reliability of PCC wire under a high temperature condition, new additive elements in the Cu core have been considered. In this paper, we investigate the role of additive elements in PCC wire and their effect on corrosion resistance under high temperature conditions. Pd and platinum (Pt) are examined as additive elements. Additive Pd and Pt in PCC wire become a cause of degradation for the stitch bond reliability under the high temperature condition due to the different degradation microstructure from conventional PCC wire. • Effects of alloying elements in copper wire material • Performance of bond reliability under high temperature environment • Intergranular corrosion in copper wire material [ABSTRACT FROM AUTHOR]

Ultra-wide bandgap materials show great promise as a solution to some of the limitations of current state of the art semiconductor technology. Among these, diamond has exhibited great potential for use in high-power, high-temperature electronics, as well as sensing and quantum applications. Yet, significant challenges associated with impurity doping of the constrained diamond lattice remain a primary impediment towards the development of diamond-based electronic devices. An alternative approach, used with continued success to unlock the use of diamond for semiconductor applications, has been that of 'surface transfer doping' - a process by which intrinsically insulating diamond surfaces can be made semiconducting without the need for traditional impurity doping. Here, we present a review of progress in surface transfer doping of diamond, both a history and current outlook of this highly exploitable attribute. [ABSTRACT FROM AUTHOR]

In this letter, we demonstrate the stability of Te–Ti thin films as a barrier against Cu after thermal annealing. Te–Ti chalcogenide glass films of composition Te0.20Ti0.70O0.10 and thickness 35nm are annealed in vacuum for up to 30min at several temperatures up to 600°C. Four-point-probe analysis results show that the Cu layers are stable up to 500°C, with abnormal increases in resistance after annealing at 600°C. The Te–Ti thin film serves as a barrier to thermal Cu diffusion up to 500°C, as revealed using Rutherford backscattering spectrometry. X-ray diffractometry indicates Cu grain growth up to 500°C and phase instability of the Te–Ti barrier at 600°C. These results indicate the potential of Te–Ti thin films as a copper diffusion barrier in high temperature microelectronics and integrated circuits. [ABSTRACT FROM AUTHOR]

Abstract: Contrast to superconducting compounds SrNi2Ge2 (Tc =1.1K) and SrPd2Ge2 (Tc =3.2K) with the BaFe2As2-type body-center-tetragonal (122-bct) layer structure (space group I4/mmm), SrPt2Ge2 crystallized in a pseudo-tetragonal, monoclinic structure with space group P21 and lattice parameters a =0.4401(4)nm< b =0.4435(4)nm, c =0.9764(10)nm and β = 90.5o >90o. Superconductivity with Tc =10.2K was observed in this new compound. However, a weak diamagnetic shielding signal of −3.2×10−2 cm3/mol at 2K indicates that superconductivity is not from the bulk monoclinic phase but from a minor metastable 122-bct high-temperature phase with a ∼0.44nm, c ∼0.98nm, β = 90o. This is the highest Tc reported outside the iron-based layer compounds with the 122-bct structure. High-Tc superconductivity is due to strong quasi-2D Pt-Ge-Pt 5dxz , yz -4p-5dxz , yz hybridization in the Pt-Ge layer with squeezed PtGe4 tetrahedral crystal field and Pt-5d 8 spin–orbital interaction in the metastable 122-bct phase and is another example of multi-band (dxz /dyz /dxy ) non-conventional s-wave superconductor. [Copyright &y& Elsevier]

• Comprehensive review of recent developments in GaN HEMT based sensors. • Sensing mechanism of various sensors explained. • Literature review of work on functionalizing the gate electrode of GaN HEMTs for various analytes. • Significant interest areas are defense, aerospace, agriculture, healthcare, and environment. • Initial reading material for beginners and research students. Gallium Nitride (GaN) belongs to III-N family of compound semiconductors, which albeit new, is well-established material system in the fields of high power, high temperature electronics and optoelectronics. Also, its properties such as high mobility, surface sensitivity, non-toxicity, thermal endurance, low power consumption make it an ideal material for realizing sensors. This paper provides a review on the significant research work done in the field of GaN based sensor technologies. We classified the work done so far, according to the applications and the different types of parameters being measured. The challenges faced by the current sensing systems and future opportunities are also briefly explained for a variety of applications viz. radiation sensors, mechanical sensors, gas sensors, biosensors, chemical sensors and high temperature Hall-effect sensors etc. Additionally, the sensing mechanism of various sensors is explained. This paper can supply initial reading material for beginners and research students working on GaN heterostructure based sensor applications. [ABSTRACT FROM AUTHOR]

• Low-cost nano-Cu 10 Sn 3 was synthesized by a one-step thermal decomposition method. • The nano-Cu 10 Sn 3 possesses good oxidation resistance under atmospheric environment. • The acquired full-Cu 10 Sn 3 joints have high enough bonding strength (26.8 MPa). Cu 10 Sn 3 intermetallic compound (IMC) nanoparticles (NPs) were synthesized by one-step thermal decomposition method with low cost. The in -situ formed metal amide in the presence of LiN(iPr) 2 can be reduced and thermally decomposed into metal NPs, and then the Cu 10 Sn 3 NPs were obtained, which have an average diameter of 65 nm and good oxidation resistance. The microstructures and mechanical properties of Cu/Cu 10 Sn 3 /Cu joints at different sintering temperatures were investigated. The full-Cu 10 Sn 3 IMC joints show high shear strength of 26.8 MPa after sintering at 300 °C for 20 min, demonstrating its broad potential as an interconnect material for high-temperature power electronics. [ABSTRACT FROM AUTHOR]

An exciting and novel science mission concept called Seismic and Atmospheric Exploration of Venus (SAEVe) has been developed which uses high-temperature electronics to enable a three-order magnitude increase in expected surface life (120 Earth days) over what has been achieved to date. This enables study of long-term, variable phenomena such as the seismicity of Venus and near surface weather, near surface energy balance, and atmospheric chemical composition. SAEVe also serves as a critical pathfinder for more sophisticated landers in the future. For example, first order seismic measurements by SAEVe will allow future missions to deliver better seismometers and systems to support the yet unknown frequency and magnitude of Venus events. SAEVe is focused on science that can be realized with low data volume instruments and will most benefit from temporal operations. The entire mission architecture and operations maximize science while minimizing energy usage and physical size and mass. The entire SAEVe system including its protective entry system is estimated to be around 45 ​kg and approximately 0.6 ​m diameter. These features allow SAEVe to be relatively cost effective and be easily integrated onto a Venus orbiter mission. The technologies needed to implement SAEVe are currently in development by several funded activities. Component and system level work is ongoing under NASA's Long Lived Insitu Solar System Explorer (LLISSE) project and the HOTTech program.. LLISSE, is a NASA project to develop a small Venus lander that will operate on the surface of Venus for 60 days and measure variations in meteorology, radiance, and atmospheric chemistry. LLISSE is developing a full-function engineering model of a Venus lander that contains essentially all the core capabilities of SAEVe thus greatly reducing the technology risk to SAEVe. The SAEVe long duration Venus lander promises exciting new science and is an ideal complimentary element to many future Venus orbiter missions being proposed or planned today. • SAEVe capitalizes on 1) latest developments in high temperature electronics; 2) science objectives focused on temporal science with low data volume and 3) a novel operations approach to achieve 120 day life. • SAEVe begins to address Venus seismic activity, crust thickness / composition, meteorology, momentum exchange between the atmosphere and planet, chemical variability, energy balance, and morphology. • This baseline mission can be realized with the two landers deployed 300–800 ​km apart. The two independent cost estimates for this novel mission architecture and concept predict that SAEVe will cost $106 ​M. • A significant risk and one that SAEVe would work down for future missions is that we have little knowledge of current Venus' seismic activity. • Almost all the technology developments needed to realize SAEVe science objectives are in work, primarily under the LLISSE project but via other programs as well. • SAEVe is an exciting mission that offers the potential for addressing long-standing science questions in a unique and innovative way. [ABSTRACT FROM AUTHOR]

When using nanopaste as bonding material, residual organics are inevitable in the sintered bondline and normally considered as having negative effects. This paper firstly finds that proper residual organics can stabilize the bondline microstructure which is very important for high temperature electronics. The results show that nanopores in the sintered bondline tend to coalesce during high temperature service and the pore size growing rate is much faster if no residual organics in the bondline. However, about 2.2 wt% residual organics can largely suppress the growing rate and almost cease the nanopore growing at 350 °C for 800 h. It is mainly because that the naturally uniformly distributed residual organics inhibit the nanopore surface diffusion. Unlabelled Image • Residual organics is inevitable in the sintered bondline and normanlly considered as having negative effects. • This manuscript firstly find that proper residual organics can stabilize the bondline microstructure. • Residual organics can largely suppress the growing rate and almost cease the nanopore growing at 350 °C for 800 h. • Proper residual organics can stabilize the bondline microstructure. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is a wide band gap material that is slowly but steadily asserting itself as a reliable alternative to silicon (Si) for high temperature electronics applications, in particular for the electrical vehicles industry. The passivation of SiC devices with diamond films is expected to decrease leakage currents and avoid premature breakdown of the devices, leading to more efficient devices. However, for an efficient passivation the interface between both materials needs to be virtually void free and high quality diamond films are required from the first stages of growth. In order to evaluate the impact of the deposition and seeding parameters in the properties of the deposits, diamond films were deposited on SiC substrates by hot filament chemical vapor deposition (HFCVD). Before the seeding step the substrates were exposed to diamond growth conditions (pre-treatment PT) and seeding was performed with a solution of detonation nanodiamond (DND) particles and with 6–12 and 40–60 μm grit. Diamond films were then grown at different temperatures and with different methane concentrations and the deposits were observed in a scanning electron microscope (SEM); their quality was assessed with Raman spectroscopy. Unlabelled Image • Diamond films were deposited on SiC substrates. • The low temperature pre-treatment given to the substrate induces the lateral growth of the diamond crystals • Seeding with 6-12 μm grit results in higher quality when compared to seeding with DND particles. • This difference is a​ttributed to the existence of an sp2 shell surrounding the DND core particles. [ABSTRACT FROM AUTHOR]

The increasing demand of high-temperature and high-power electronics has triggered intensive research on capacitors with operation temperature up to 300 °C. In this work, dielectric properties of (1-x)[0.91Bi 0.5 Na 0.5 TiO 3 -0.09BiAlO 3 ]-xSrTiO 3 (BNT-9BA-100xST) ceramics are studied. BNT-9BA-15ST has a stable permittivity between 96.7 °C and 396.8 °C and the dielectric loss is below 0.02 in the temperature range of 132.8 °C–391.8 °C. Furthermore, frequency dependent conductivities of BNT-BA-100xST are analyzed by a universal dynamic response (UDR) and nearly constant loss (NCL) behavior. Besides, the energy storage properties are studied and the recoverable energy storage density of BNT-9BA-15ST (W rec) is 0.84 J/cm3 at room temperature under the electric field of 90 kV/cm. And the variance of W rec is smaller than ±15% in the temperature range of 20 °C–180 °C. Thus, this work provides a new candidate of dielectrics used for capacitors at high temperature. • High-temperature dielectrics BNT-9BA-100xST were designed. • Frequency dependent conductivities are analyzed by UDR and NCL behavior. • BNT-9BA-15ST has stable permittivity and low dielectric loss. [ABSTRACT FROM AUTHOR]