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In this article, a novel broad circularly polarized antenna (CPA) with circular-slot ground is presented. The circular-slot CPA is consisted of a circular-slot ground, an I-shaped slit and a semicircle loop feeding structure. By using semicircle loop feeding structure and adding a slit into the circular-slot ground as perturbation elements, the multiple CP resonant modes could be stimulated simultaneously. To demonstrate to the design radiational, an antenna model was printed, manufactured, and tested. The tested results reveal that the proposed antenna has a broad 3-dB ARBW of |S11

In this letter, two novel broadband circularly polarized slot-microstrip antennas (SMPA) with circular and square structures are elaborated. The circular SMPA is composed of four crown patches as parasitic elements, four crown slots etched on a circular ground plane, and a circular loop sequential phase feeding structure. However, the square SMPA consists of four parasitic rectangular patches, four square slots with cut corners, and a square-loop feeding structure. In the circular SMPA, the parasitic crown patches and crown slots are used to excite multiple circularly polarized (CP) resonant modes, which are fed by a circular loop sequential phase feeding structure through capacitive coupling. Combined with these CP modes, the CP bandwidth of the presented antenna could be improved. Eventually, the proposed circular SMPA has a broad 3-dB axial ratio bandwidth (ARBW) of 20.6% (5.206.40, 5.8 GHz) and a wide 10-dB impedance bandwidth (IBW) of 25.8% (4.926.38, 5.65 GHz), which could occupy the WLAN (5.7255.85 GHz), ITS (5.8 GHz), and WIFI (5.85-5.925 GHz) bands.

In this paper, systematic characterization of the dual probe, which is designed for the near field simultaneous measurement of both electric and magnetic field, is investigated with a microstrip line as the device under test (DUT). The characterization includes frequency response, transmission performance, symmetry, reflection, the intrusion of probe to the DUT, isolation of electric and magnetic field responses, field profile and spatial resolution, and differential electric field suppression. The dual probes with different design are adopted to demonstrate the systematic characterization.

An extended model of through-silicon via (TSV)-based solenoid inductor is proposed to save on-chip areas for 3-D radio frequency (RF) ICs and package integration. To achieve a high inductance density, the nested topology consists of high-density TSVs in high-resistivity silicon substrate and multilayers of metals in compatible CMOS process. Then, an analytical inductance model, considering the mutual inductance of TSVs and complicated metal traces, is established and verified. The inductance variation in physical dimensions is studied based on the modeled and simulated results of a TSV solenoid inductor in single tier. The proposed TSV solenoid typology gets better performance at inductance density and quality factor around some frequencies through analytical model and full-wave simulations. Further studies are directed toward RF application overview according to broadband and low power consumption.

AC positive bias temperature instability (PBTI) of germanium nMOSFETs with GeO2/Ge and Si-cap/Ge gate stack was investigated in this brief. AC-DC-AC alternating PBTI stress tests were conducted on both types of devices, the experiment data shows the inserted DC stress phase has little impact on the following AC stress kinetics on GeO2/Ge nMOSFETs but introduce a significant “additional DC generation” on Si-cap/Ge devices. The “additional DC generation” is ascribed to the existence of energy alternating defects (EAD) according to previous studies. Energy distribution under DC and AC stress further demonstrate that EAD are significant on Si-cap/Ge but negligible on GeO2/Ge devices. Effective lifetime prediction is carried out and compared under DC stress after discharge (with a purposely introduced measurement delay) and AC stress on both GeO2/Ge and Si-cap nMOSFETs. The results show GeO2/Ge nMOSFETs’ effective lifetime exhibits no difference under two stress modes, while Si-cap/Ge nMOSFETs’ effective lifetime is underestimated using DC stress after discharge approximation without considering the EAD-induced “additional DC generation”. An extra 0.14V 10-year Vdd design margin can be obtained for Si-cap/Ge nMOSFETs to gain higher performance by taking “additional DC generation” into account. The conclusion is beneficial for process optimization and PBTI reliability improvement of Ge nMOSFETs.

Recent studies reported that PIG negative hydrogen ions extraction for neutron tube is superiority to positive hydrogen ions extraction. Present maturing products of neutron tube on market almost use PIG ion source and extract positive hydrogen ions. If negative hydrogen ions extraction can be applied on present products, the combination property will be greatly improved. In this study, a contrast experiment of PIG positive and negative hydrogen ion source for D–T neutron tube is put into effect. The relationships between the current of ion source, the beam current and the voltage extraction are investigated. The experiment results demonstrate that the negative ion extraction has higher yield of neutron for unit target current. We also point out that the ratio of yield to target current is a considerable parameter to reflect the overall performance of neutron tube.

Radio-frequency interference (RFI) problems in modern electronic product become complex which result in the increasing number of scanning points. Conventional near-field phaseless source reconstruction methods such as double planes iteration method and single plane iteration method will spend a lot of time in both scanning and calculating. To save the calculating time and scanning time, an alternating iterative method is proposed for source reconstruction based on magnitude-only and single-plane near field scanning. Firstly, the single-plane scanning data is divided into two groups as group A and B according to the components, i.e. the electric field group and the magnetic field group for the four components, or ${H_{x}}$ group and ${H_{y}}$ group for two components. Then, the processed A and B phaseless data groups are used iteratively in the back-and-forth transformations to get the equivalent dipole elements. Under the premise of a large amount of scanning data, such as the simulation example, compared with conventional method filling the scanning data into a whole matrix, the proposed method can save 90% calculating time, especially the time in singular value decomposition (SVD) before the iteration. A numerical simulation and a measurement example is verified the effectiveness of the proposed method, which show a comprise between accuracy and efficiency.

Electromagnetic patterns in near field scanning usually give important information about the source inside an device under test. In this paper, we develop a postprocessing technique, including standard-deviation-based method, principal component analysis, and K -means method, so that the electromagnetic patterns in near field scanning can be extracted fast and grouped automatically and efficiently. The postprocessing techniques are applied to experimental near-field scanning of ICs, such as a microcontroller unit (MCU) and a field programmable gate array (FPGA). The grouping on the electromagnetic patterns of the MCU is in good agreement with the published grouping result, and the grouping on the electromagnetic patterns of the FPGA can find out the additional cluster responsible for additional circuit.

To measure the magnetic near field with high common-mode noise rejection, a probe with the differential and symmetrical structure forming a detection loop is developed. Such measurement is performed by using a two-port vector network analyzer (VNA) and validated by using a microstrip line as a device under test (DUT). In comparison to the measurement with traditional single-output magnetic near field probe, the electric field suppression of the proposed measurement can be improved by at least 10 dB in the frequency range of $3\sim 11$ GHz, while the other characteristics remain unchanged.

In this paper, the radiated emission of a microcontroller integrated circuit is investigated by rotating the test board in a transverse electromagnetic (TEM) cell measurement. The dependence of the radiated emission on the angle of rotation is derived on the basis of the coupling between a microstrip line and the TEM cell, and then validated by the multiple-orientation TEM cell measurements in a quantitative accuracy of fitting. With the validated dependence, the radiated emissions contributed by electric and magnetic coupling are extracted. The extracted emissions are found in agreement with the measurement result by near-field scanning experiments.

With the trend of miniature, high-integrated assembly modules are common in modern industry. The measurement of the flowing current and voltage on a trace is basic for diagnosis and monitoring of these modules. The traditional contact detection method is not practical especially in conditions of high power and small space. In this paper, we demonstrate a novel method for collocated and simultaneous measurements of radio frequency current and voltage on a trace in a noncontact and movable manner. The measurements are achieved by using a compact probe with both voltage and current detectors, as well as an algorithm based on the transfer functions quantifying the capacitive and inductive couplings between the detectors and the tested trace. The proposed method is verified and applied for continuous power measurements, collocated and simultaneous measurements of transient voltage and current pulses and the dynamic voltage and current of a switching device.

A near-field scanning is usually time-consuming to map the electromagnetic field along the surface of a device. In this communication, a dual probe is proposed with a U-shaped loop to sense radio frequency (RF) magnetic and electric fields simultaneously, so that the one-time scanning by the dual probe can replace the two-time scanning by single-detector probes. Different from the traditional near-field scanning by using a single-detector probe and spectrum analyzer, the proposed scanning can be achieved by the two-output probe and a two-port vector network analyzer connecting to the probe. The efficient near-field scanning measurements of the electric and magnetic field on a conductor-backed coplanar waveguide transmission line and an RF power divider by using the dual probe are in agreement with those by using two single-detector probes.

Hexagonal ground-shielding through silicon vias (TSVs) in 3D ICs are explored based on measurement and simulation. The measured S-parameters of the TSV-bundle part are successfully extracted by de-embedding technique. The results math well with simulations up to 20GHz. The proposed TSV bundle has a good performance of return and insertion loss. For the hexagonal ground TSV shield system, the crosstalk analysis of neighbor signals in the TSV shield system is made based on the measurements and simulations. The electronic and magnetic field plots show a good capacitive and inductive coupling isolation for the victim signal TSV with shielding ground TSVs. Compared to those coupled-TSVs systems without ground guide, the ground-shielding TSV as well as coaxial TSV has higher noise over the range of frequencies.

We have investigated the debonding failure of the through-silicon via (TSV)–Cu/Si interface during annealing treatment at 425 °C. The interface microstructure was characterized by two parameters: the TSV–Cu/Si interface roughness and the Cu seed layer grain size. Scanning electron microscopy observation of the cross-section of the TSV–Cu/Si interface was performed to analyze the effect of the interface microstructure on its microcrack failure. In addition, qualitative numerical simulations were performed to investigate the effect of the TSV–Cu/Si interface roughness and Cu seed layer grain size on the overall response of the TSV–Cu/Si interface crack. The experimental results indicate that most of the TSV interfacial cracks propagate along the Cu seed layer after annealing, and the crack length of the TSV–Cu/Si interface increases with increasing interface roughness and Cu seed layer grain size. The numerical simulation is constructed to reveal the interfacial crack mechanism, and the results suggest that the stress concentration in the Cu seed layer which influence by interface roughness and Cu grains size is the main driving force for interfacial cracking. Based on the experimental and simulation results, guidelines for controlling the TSV-Cu/Si interfacial cracking from the perspective of the TSV manufacturing process are proposed.

This paper presents a noncontact radio frequency voltage sensing of a printed trace by using a capacitive-coupled probe. The noncontact voltage sensing is demonstrated by using an open-end coaxial probe, and achieved through the transfer factor from the printed trace to the probe and a reconstruction algorithm. To validate the voltage sensing, known periodic, and pulse voltages are injected into the printed trace and compared with the reconstructed waveforms. Our results demonstrate that the voltage sensing method can be used for measurement of a random waveform with period even down to 1 ns and single pulse with rise time down to 2 ns. In consideration of the flexible relocation of the probe, the voltage sensing accuracy caused by spatial errors is also investigated.

Degradation characteristics and mechanisms of AlGaN/GaN high electron mobility transistors (HEMTs) were investigated under swift heavy-ion irradiation. AlGaN/GaN HEMTs were exposed to 800 MeV Bi ions with fluence up to 5.28 × 10 10 ions/cm 2 . Post-irradiation measurement shows that the saturation drain current reduced by 15%, the maximum transconductance decreased by more than 27%, and both the positive and negative gate characteristics degraded dramatically. By the off-state examination using the Photo Emission Microscopy (PEM), electroluminescence hot spots were found in the gate areas, which indicates new leakage passages produced by heavy-ion bombardment. Micro cross sections were prepared at hot spot areas by dual-beam focused ion beam (FIB) and examined using transmission electron microscope (TEM). The presence of latent tracks throughout the whole hetero-junction area was confirmed. Latent tracks, which related to the high density ionizing energy-loss, play a role of new leakage paths and account for the increment of gate leakage. Moreover, nonionizing energy-loss induced defects decrease the charge density in the two-dimensional electron gas (2DEG) and reduce the carrier mobility, leading to the degradation of device output performances.

This paper presents the total ionizing dose (TID) radiation performances of core and input/output (I/O) MOSFETs from 130 nm partially-depleted silicon-on-insulator (PDSOI). Both the core NMOS and PMOS are totally hardened to 1.5 Mrad(Si), while the I/O devices are still sensitive to TID effect. The worst performance degradation is observed in I/O PMOS which is manifested as significant front gate threshold voltage shift and transconductance decrease. Contrary to PMOS, front gate transconductance overshoot is observed in short channel I/O NMOS after irradiation. A radiation induced localized damage model is proposed to explain this anomalous phenomenon. According to this model, the increments of transconductance depend on the extension distance and trapped charge density of the localized damage region in gate oxide. More trapped charge lead to more transconductance increase. These conclusions are also verified by the TCAD simulations. Furthermore, the model presents a way to extract the trapped charge density in the localized damage region.

In this paper, we study the orientation effect of magnetic and electric field-to-line coupling (FtLC) between a microstrip line and a TEM cell by using a square-shaped transmission line pulse as an interference source. With the detections at enough orientations, the electric and magnetic FtLCs can be extracted with high accuracy. It is found that in the TEM cell, the ratio of electric to maximum magnetic FtLC is dominated by the characteristic impedance of the studied microstrip line due to the determined value of width-to-distance. For a certain ratio of electric to maximum magnetic FtLC, there is a singular angle at which the microstrip line gives no response for any electromagnetic interference excitation. Meanwhile, at the supplementary angle, the response of the microstrip line shows no dependence on the termination load.

In this paper, the electrical properties and low-frequency noise for bipolar junction transistors irradiated by 170 keV proton are examined. The result indicates that for the sample under proton irradiation with fluence 1.25 × 1014 p/cm2, base current IB in low bias range (VBE < 0.7 V) increases due to superimposition of radiation-induced recombination current, while the gain decreases significantly. Meanwhile, the low-frequency noise increases in the proton-irradiated sample. By analysis of evolution of parameters extracted from low-frequency noise power spectra, it is demonstrated that radiation-induced noise is mainly originated from carrier fluctuation modulated by generation–recombination centers (G–R centers) located at the interface of Si/SiO2, which are introduced by proton-radiation-induced defects. It is also confirmed that the electrical properties and noise behavior of irradiated sample are mostly affected by the carrier recombination process caused by G–R centers at the interface of S...

To provide a guideline for converter design and fault protection, the failure mechanism and reliability of silicon carbide (SiC) power MOSFETs needs to be further investigated. In this paper, the failure mechanism during short-circuit (SC) of commercial 1.2-KV/19-A SiC power MOSFETs was investigated. After the SC tests, the I ds of the device decreased significantly. Moreover, it was found that the V th and I gs increased obviously. The results demonstrated that negative charges were captured by the gate oxide and accumulated during the SC tests, which is eventually causes degradation of the gate oxide. The results of this study may be useful in the design and application of SiC power MOSFETs.

With the development of avionics system, the demand of health metrics of integrated system is getting stronger and stronger. By describing the requirements and resources of an integrated system logically, a requirementoriented health metrics method of integrated system is proposed in this paper, then a reconstruction model of system resources is proposed depend upon the method. Furthermore, the decision-making method based on health metrics of integrated system is discussed.

Only bulk diffusion occurs in the solder joint of the monocrystalline structure without grain boundary diffusion. The migration direction of intermetallic compounds (IMCs) is mainly determined by grain orientation. Correspondingly, both bulk diffusion and grain boundary diffusion exist in the polycrystalline structure solder joints. The grain boundaries with random orientation and different lengths are distributed in the bumps, which can effectively inhibit the IMCs migration under the stressing of electron flow. The structure of lead-free solders mainly composed of Sn-based solder tends to nucleate cyclic twin structure with only two grains. The misorientation angle between the two grains is calculated to be a constant value of 57.2 degrees in this study. It is confirmed that the solder joints of the cyclic twin structure have a excellent inhibitory effect on electromigration failure.

Electromigration was characterized at the cathode Cu/solder interface&mdash, without the effect of Joule heating&mdash, by employing scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) analyses. Rapid (Cux,Ni1&minus, x)6Sn5 intermetallic compound (IMC) growth was observed at the anomalous region at the cathode end due to the effect of current crowding. The abnormal isotropic diffusion and parallel distribution of Pb were characterized in an ultra-low temperature environment in a monocrystalline structure stressed at &minus, 196 &deg, C. The interesting results were attributed to crystallographic transformation due to the simultaneous effect of cryogenic and electrical stressing. The diffusion behavior of Pb atoms in face-centered cubic lattices performed isomorphism. As a result, Pb atoms of the bump gathered at the high-energy grain boundaries by diffusing through the face-centered cubic lattices around the long grain boundary, eventually forming a long-range distribution and accumulation of Pb elements. Our study may provide understanding of cryogenic electromigration evolution of the Cu/solder interface and provide visual data for abnormal lattice transformation at the current stressing.

The decay length scaling behavior of state-to-state coupling between silicon valence band $(VBMsi)$ and oxygen vacancy defect $(E_{defect})$ in Si/SiO2 interface is thoroughly investigated by density-functional theory. The detailed coupling process is revealed, and the scaling rate with interface-defect distance is obtained. Results show that the coupling constants $(Vc)$ decay with the defect distance is not so fast as the WKB approximation predicts, and the reason lies in the fact that the tunneling picture overestimates the localization of the defect states.

To deeply understand the charge trapping process in high-k gate stacks, we theoretically investigate the hole trapping characteristics of interfacial oxygen vacancies in (110) and (100) Si/SiO 2 /HfO 2 stacks. Si/SiO 2 and SiO 2 /HfO 2 interfacial defects are studied, and the hole trapping rate of each defect is calculated through ab initio simulation combining density-functional theory and Marcus theory. Among the possible hole traps considered in this work, it is suggested that the oxygen vacancies at SiO 2 /HfO 2 interface are the dominant under strong negative gate bias stress, and those at Si/SiO 2 interface can be effective traps only when hydrogen atom (H) or hydroxyl (OH) is induced at the vacancy. Moreover, the most dominant hole trap among the considered traps in the (110) structure locates at the Si/SiO 2 interface, while that in the (100) structure locates at the SiO 2 /HfO 2 interface.

Lithium sulfur (Li-S) batteries are very promising electrochemical storage system due to their high gravimetric energy density and low cost. Enormous efforts have been put on Li-S battery to achieve its commercialization. The function of electrolyte is a key issue in achieving the high performance of Li-S system, and several additives have been tried. But very few works have been working on the electrolyte optimization method with the consideration of over-all performance, including cycling stability, rate capability, especially self-discharge prevention ability, and the consideration of loading condition. In this work, we focus on the incorporation of room temperature ionic liquid (IL) as co-solvent, and the effect of IL in mitigating the polysulfide dissolution via systematical mechanism study of self-discharge phenomena. Moreover, the optimization of IL incorporation ratio is discussed for the sake of the better over-all electrochemical performance of Li-S cell by considering cycling stability, rate performance and self-discharge prevention ability, which is found to vary with loading condition. The improved understanding of the effect of IL on battery performance will help the development of electrolyte for Li-S batteries.

Displacement damage induced degradations in four-junction solar cells are investigated by electron irradiation and TCAD simulation. It shows that In0.3Ga0.7As cell is the key sub cell to affect the radiation tolerance of four-junction solar cell. Although irradiation will introduce relatively uniform displacement damage in each sub cell of four-junction solar cell, the In0.3Ga0.7As cell show the most significant degradation under the same radiation damage conditions. The radiation harness of the four-junction solar cell can be promoted by increase the short circuit current of In0.3Ga0.7As cell before irradiation, which is verified by the TCAD simulations. The relationship between electrical characteristics degradations and the displacement damage dose is established for four-junction solar cells. Then, the equivalent displacement damage dose method has been used to predict the on-orbit degradation of four-junction solar cells. The degradations of the four-junction solar cells on typical geosynchronous earth orbit are calculated by combining Monte Carlo simulations and ground irradiation test data.

This paper presents a novel VSWR measurement system for high power electronic vacuum device such as traveling wave tube in working mode. The measurement principles of this VSWR measurement system have been presents. The feasibility of this VSWR measurement system has been analyzed.

In this paper, we change terminal loads of a microstrip line to separate electric field coupling and magnetic field coupling between a microstrip line and a transverse electromagnetic (TEM) cell during radiated emission measurement. Such separation can also be validated by another terminal load. After validation, the effect of termination on both couplings is investigated, and the requirements of termination impedance to suppress the two couplings are revealed. In addition, we find that the linear physical models deriving both lumped coupling parameters only hold below a limited frequency.

In this paper, we investigated on -state electroluminescence (EL) characteristics in fresh GaN-based HEMTs under different on -state bias conditions. It demonstrated that: 1) the intensity of the on -state EL emitted by the GaN-based HEMTs with relatively high ${\rm V}_{\rm DS}$ $({\rm V}_{\rm DS}>10\ \hbox{V} )$ monotonically increased as the gate voltage increased; and 2) the distribution of the intensity of the on -state EL was uniform along the gate and across the device before stress tests. The degradation process and mechanisms of the devices in the high temperature operation (HTO) stress were also analyzed based on the on -state EL characterization, the electrical measurement, and failure analysis. It demonstrated the following. First, the on -state EL distribution of the device after step HTO (S-HTO) stress tests was no longer uniform along one of the fingers, which indicated that the degradation was related to this finger. This hypothesis was confirmed by the SEM observation after the deprocess of the gate metal and the SiN passivation layer. Second, a new degradation mechanism of AlGaN/GaN HEMTs that caused the abrupt degradation in the S-HTO stress was identified and related to the emergent, localized, and jagged crack under the gate metal. Third, there was no abrupt degradation in the long-term HTO (LT-HTO) stress test. However, the on -state EL intensity of the inner fingers in the device after the LT-HTO stress test decreased more than that of the outer fingers, which meant that the degradation of the inner fingers was faster than that of the outer fingers as a result of the higher temperature caused by self-heating in the inner region of the device. Finally, the gradual degradation in the LT-HTO stress test was ascribed to the gradual formation of structural damage along the drain side of the whole gate edge, which was confirmed by the SEM observation.

Field Programmable Gate Array (FPGA) system is widely used in deep learning application and cloud system for acceleration. Quality and reliability of IP block is essential to the successful development of today's complex hardware acceleration design. In this paper, we discuss the important issues of quality and reliability of digital soft IP, and propose a qualification measurement system that can evaluate IP quality. The metric system consists of eight categories to characterize IP quality. Based on this indicator system, we propose an IP qualification frameworks. As a case study, the proposed framework has been used to qualify three open source IP cores. The experimental results show that the proposed metric system and qualification framework can not only quantify the quality of IP, but also speed up the certification process and improve the accuracy of the certification results.

As we known, the measurement of junction-to-case thermal resistance (R th -JC) of semiconductor power devices is very important. In this paper, an approach of transient dual interface method (TDIM) with gate-source voltage (Vg s ) as the temperature sensitive electrical parameters (TSEP) was investigated for the measurement of R th -JC of packaged SiC MOSFET. The measured R th -JC value of packaged SiC MOSFET is in the range of 1.61 K/W to 1.76 K/W, and compared with the typical value of device specification, the maximum error is 5.29 %. The results show that the thermal resistance measurement of packaged SiC MOSFET by TDIM with Vg s as the TSEP is feasible, and it is of good accuracy and reproducibility.

Semiconductor technology and packaging is advancing rapidly toward system integration where the packaging is co-designed and co-manufactured along with the wafer fabrication. However, materials issues, in particular the mesoscale microstructure, have to date been excluded from the integrated product design cycle of electronic packaging due to the myriad of materials used and the complex nature of the material phenomena that require a multiphysics approach to describe. In the context of the materials genome initiative, we present an overview of a series of studies that aim to establish the linkages between the material microstructure and its responses by considering the multiple perspectives of the various multiphysics fields. The microstructure was predicted using thermodynamic calculations, sharp interface kinetic models, phase field, and phase field crystal modeling techniques. Based on the predicted mesoscale microstructure, linear elastic mechanical analyses and electromigration simulations on the ultrafine interconnects were performed. The microstructural index extracted by a method based on singular value decomposition exhibits a monotonous decrease with an increase in the interconnect size. An artificial neural network-based fitting revealed a nonlinear relationship between the microstructure index and the average von Mises stress in the ultrafine interconnects. Future work to address the randomness of microstructure and the resulting scatter in the reliability is discussed in this study.