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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.

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, 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.

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.

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.

In this paper, a simulation tool named the neutron-induced single event effect predictive platform (NSEEP2) is proposed to reveal the mechanism of atmospheric neutron-induced single event effect (SEE) in an electronic device, based on heavy-ion data and Monte-Carlo neutron transport simulation. The detailed metallization architecture and sensitive volume topology of a nanometric static random access memory (SRAM) device can be considered to calculate the real-time soft error rate (RTSER) in the applied environment accurately. The validity of this tool is verified by real-time experimental results. In addition, based on the NSEEP2, RTSERs of 90 nm–32 nm silicon on insulator (SOI) and bulk SRAM device under various ambient conditions are predicted and analyzed to evaluate the neutron SEE sensitivity and reveal the underlying mechanism. It is found that as the feature size shrinks, the change trends of neutron SEE sensitivity of bulk and SOI technologies are opposite, which can be attributed to the different MBU performances. The RTSER of bulk technology is always 2.8–64 times higher than that of SOI technology, depending on the technology node, solar activity, and flight height.

The instabilities of indium–zinc oxide thin film transistors under bias and/or illumination stress are studied in this paper. Firstly, illumination experiments are performed, which indicates the variations of current–voltage characteristics and electrical parameters (such as threshold voltage and sub-threshold swing) are dominated by the stress-induced ionized oxygen vacancies and acceptor-like states. The dependence of degradation on light wavelength is also investigated. More negative shift of threshold voltage and greater sub-threshold swing are observed with the decrease of light wavelength. Subsequently, a negative bias illumination stress experiment is carried out. The degradation of the device is aggravated due to the decrease of recombination effects between ionized oxygen vacancies and free carriers. Moreover, the contributions of ionized oxygen vacancies and acceptor-like states are separated by using the mid-gap method. In addition, ionized oxygen vacancies are partially recombined at room temperature and fully recombined at high temperature. Finally, low-frequency noise is measured before and after negative bias illumination stress. Experimental results show few variations of the oxide trapped charges are generated during stress, which is consistent with the proposed mechanism.

This paper proposed a two-dimensional thermal impedance model for amorphous silicon thin film transistors (a-Si:H TFTs) from a system of coupled energy equations, heat flowing equations and boundary conditions. By using of this model, the channel temperature distribution and thus the maximum channel temperature can be calculated. This model can be applied to describe the thermal behavior and thermal reliability of a-Si:H TFTS in the design phase.

Total ionizing dose (TID) radiation effects in the bipolar voltage comparator with different biases and dose rates were investigated in this paper. The experimental results show that offset voltages shift after irradiation. Dominated by the current gain degradation of differential PNP transistors, the shifts of offset voltage and output characteristics were significantly affected by biases at high dose rate. Dominated by the current gain degradation of NPN transistors, the shifts of offset voltage and output characteristics were similar in all biases at low dose rate.

We have submitted the AlGaN/GaN High electron mobility transistors (HEMTs) to the high temperature reverse bias(HTRB) stress to assess their reliability for high voltage operations. The effects of HTRB stress as a function of the V DG and stress time on the DC parameters and trapping effects were investigated. The study was based on combined DC and pulsed characterization, transient measurement. It provides the following information: 1) the exposure to HTRB may result in a permanent degradation in on-state current, the transconductance, and a slightly positive shift of threshold voltage; 2) the high temperature (T A =175°C) step reverse bias (V DG stepped from 20V to 80V) stress tests revealed that the gate leakage current I GS increased abruptly after 50V stress voltage V DG ; 3) interestingly, the long term high temperature moderate reverse bias(V DG 40V) stress resulted in some positive effects such as the decrease of gate leakage current, improved gate lag characteristics and the decrease of current collapse in pulsed measurement during the whole test; 4) the reverse-bias voltage is the key factor but for reliability assessment of AlGaN/GaN HEMTs for high voltage application based on HTRB stress; 5) The degradation mechanism of the gate leakage current under relatively high voltage HTRB test has been ascribed to the degradation metal and semiconductor interface; 6) the improved I-V characteristic under moderately voltage HTRB test has been attributed to the reduction of lateral tunneling current.

Along with the infrared technical rapid development, infrared radiation (IR) thermal imaging technology is widely applied in device and circuit reliability research. For device and circuit reliability study, IR thermal imaging technology is best for getting the peak temperature and temperature distribution. With the peak temperature and temperature distribution, the thermal information of the devices were evaluated and optimized to meet the design requirement. Secondly, IR thermal imaging technology is used to position hotspot for failures analysis, example for especially increases in elevated leakage currents. However, IR thermal imaging technology can provide evidence of excessive temperature rise due to power dissipation. It can identify root-cause of failures at temperatures below expectations.

The total-dose-induced edge effect in SOI NMOS transistors with different layouts is presented. Experimental results show that the edge effect is very sensitive to their layouts. Among the transistors hardened by design, the H-gate and ringed-source transistors do not behave as expected. At high radiation doses, the edge leakage currents appear for both transistors. Compared to the unhardened two-edged transistor, their total-dose-induced edge leakage paths and the role of layouts on edge effect are discussed.

Total Dose ionizing radiation response of substrate PNP transistors have been investigated as functions of biases and dose rates. The experiment result shown that emitter-base junction bias dominates dose rate effects in the SPNP transistors. By considering of radiation induced interface traps and oxide trapped positive charges, the degradation mechanisms have been discussed based on space charge model. In addition, the worst case biases in the SPNP transistor with different dose rates are also discussed in this paper.

This paper proposed a physical model for reverse subthreshold currents in the amorphous silicon thin film transistors. Firstly, an approximation for the band bending in the back interface as a function of gate-source voltage is derived. By considering of deep states, a current model based on electron conduction in the back channel is then developed. Finally, the proposed model was verified using the experimental data.

This paper investigates the total dose effects of substrate PNP transistors through experiments. By considering of oxide trapped positive charges and interface traps, the radiation induced excess base current in the irradiated SPNP is simulated. The simulation results showed similar trends with the experimental results, thus the mechanisms of total dose effects in the SPNP transistors are verified.

Ionization radiation causes ESD protection structure of integrated circuit degradation. A new method using Transmission Line Pulse (TLP) test is introduced in this article; this method gives more detailed information of the ESD protection structure's degradation. Turn-on voltage, hold voltage, turn-on resistance of two type ESD protection structures are measured before and after TID radiation test, results are discussed.

An investigation of thermal effects in a high power 3-5μm solid state laser pumped with different pump beam transverse profiles is carried out by COMSOL software based on the finite element method, and the temperature of the crystal center where the Super-Gaussian distributed light projected area is 81.8°C, and is bigger than that of Gaussian pump light mode and top plane pump light mode.

Total dose dependence of bias current and offset voltage in the linear operational amplifier μA741 with different bias is presented in this paper. The experimental results show that the bias current in the μA741 with grounded bias is significantly affected by the degradation of the differential input transistors. In addition, the offset voltage is affected by the degradation of bipolar transistors of the current source in the differential input stage.

In this paper, effect of bias dependence of substrate NPN (SNPN) transistors on total dose radiation is investigated. By considering of bulk field and fringing electric field in the oxide, the degradation mechanisms are discussed in numerical simulations. Experimental results show that the applied emitter voltage and the emitter-base junction bias play important roles in the total dose irradiation effect of SNPN transistors, which is agreement with the theoretical analysis.

High power laser diodes have found wide spread applications as pump sources for solid state lasers or in direct material processing. Due to the high electrical and optical power densities in the laser structures the reliability is still questionable. We report on lifetime testing of a high power cm-bar arrays using an automated diode array reliability experiment. This computer controlled setup operates the cm-bar array 24 hours a day, and three groups of different operating condition aging test were carried on. Analysis of the aging data suggest that the extrapolated lifetime of cm-bars at 25°C can reach 7950 hours (2.86×109 shots).

Oxide trapped charges which were produced in oxide area of MOSFET in the process of using can cause ESD characteristic changed. So the gate forced given bias to Simulate oxide trapped charges. In this paper, TLP test method was used to study the ESD parameters of NMOSFET with various gate biases. It was indicated that the threshold voltage V t1 and secondary breakdown current I t2 first increased and then decreased with the gate voltage increasing, but the maintained Voltage V sp essentially unchanged.

Three groups of lifetime test were completed, according to the statistical knowledge, the degradation model of cm-bars is obtained using the short-term working datas, then we obtain the extrapolated lifetime of cm-bars at 25°C is 7950 hours (2.86×109 shots), and we also obtain an acceleration factor 1.88 of resulting in a thermal activation energy of Ea=0.21eV using Arrhenius function.

The reliability, long-term performance and lifetime of high power diode lasers are important issues for pumping of solid state and fiber laser systems. In order to obtain the lifetime data of high power QCW 808nm cm-bars, we have set up a computer controlled diode array reliability experiment which can automated monitor the laser arrays 24 hours a day. Using this setup 10 high power QCW cm-bars currently being tested was operated for more than 5.4 billion shots at 25 0 C with a pulse width of 200us and a duty factor of 2%, and one cm-bars suffered sudden failure at 3.24x10 7 shots, one cm-bars had reached the failure criterion at 1.98 billion shots. The failure analysis of these two failed device were reported on this paper. Keywords-reliability, laser diode, lifetime, sudden failure, failure analysis.

The irradiation response of DC-DC power converter is studied using X-ray source. During the test, DC-DC power converter is unsteady and the characteristic parameter such as input current and output voltage was strong influenced by the total-irradiation-dose. It is indicated that optical coupler in DC-DC power converter is tremendous affected by irradiation, but the ultimate failure of DC-DC converter is due to the VDMOSFET broken out.

Low frequency noise behaviors of partially depleted silicon-on-insulator (PDSOI) n-channel metal-oxide semiconductors (MOS) transistors with and without ion implantation into the buried oxide are investigated in this paper. Owing to ion implantation-induced electron traps in the buried oxide and back interface states, back gate threshold voltage increases from 44.48 V to 51.47 V and sub-threshold swing increases from 2.47 V/dec to 3.37 V/dec, while electron field effect mobility decreases from 475.44 cm2/Vs to 363.65 cm2/Vs. In addition, the magnitude of normalized low frequency noise also greatly increases, which indicates that the intrinsic electronic performances are degenerated after ion implantation processing. According to carrier number fluctuation theory, the extracted flat-band voltage noise power spectral densities in the PDSOI devices with and without ion implantation are equal to 7×10−10 V2Hz−1 and 2.7×10−8 V2Hz−1, respectively, while the extracted average trap density in the buried oxide increases from 1.42×1017 cm−3eV−1 to 6.16×1018 cm−3eV−1. Based on carrier mobility fluctuation theory, the extracted average Hooge's parameter in these devices increases from 3.92×10−5 to 1.34×10−2 after ion implantation processing. Finally, radiation responses in the PDSOI devices are investigated. Owing to radiation-induced positive buried oxide trapped charges, back gate threshold voltage decreases with the increase of the total dose. After radiation reaches up to a total dose of 1 Mrad(si), the shifts of back gate threshold voltage in the SOI devices with and without ion implantation are −10.82 V and −31.84 V, respectively. The low frequency noise behaviors in these devices before and after radiation are also compared and discussed.

We investigate the effects of 60Co γ-ray irradiation on the 130 nm partially-depleted silicon-on-isolator (PDSOI) input/output (I/O) n-MOSFETs. A shallow trench isolation (STI) parasitic transistor is responsible for the observed hump in the back-gate transfer characteristic curve. The STI parasitic transistor, in which the trench oxide acts as the gate oxide, is sensitive to the radiation, and it introduces a new way to characterize the total ionizing dose (TID) responses in the STI oxide. A radiation enhanced drain induced barrier lower (DIBL) effect is observed in the STI parasitic transistor. It is manifested as the drain bias dependence of the radiation-induced off-state leakage and the increase of the DIBL parameter in the STI parasitic transistor after irradiation. Increasing the doping concentration in the whole body region or just near the STI sidewall can increase the threshold voltage of the STI parasitic transistor, and further reduce the radiation-induced off-state leakage. Moreover, we find that the radiation-induced trapped charge in the buried oxide leads to an obvious front-gate threshold voltage shift through the coupling effect. The high doping concentration in the body can effectively suppress the radiation-induced coupling effect.

Frequency dependent conductance measurements are implemented to investigate the interface states in Al2O3/AlGaN/GaN metal-oxide-semiconductor (MOS) structures. Two types of device structures, namely, the recessed gate structure (RGS) and the normal gate structure (NGS), are studied in the experiment. Interface trap parameters including trap density Dit, trap time constant τit, and trap state energy ET in both devices have been determined. Furthermore, the obtained results demonstrate that the gate recess process can induce extra traps with shallower energy levels at the Al2O3/AlGaN interface due to the damage on the surface of the AlGaN barrier layer resulting from reactive ion etching (RIE).