Papers by Keyword: Failure Analysis

Abstract: This study investigates the role of in-grown stacking faults (SF) in the bipolar degradation of 3.3 kV SiC-MOSFETs, emphasizing their significant contribution to both on-resistance (V_DSon) and leakage current (I_DSX) degradation. A high current stress was applied to over 1,500 chips, resulting in 72 degraded devices, with 45 exhibiting notable I_DSX degradation. A detailed analysis revealed that most I_DSX degraded chips contained bar-shaped in-grown SFs, suggesting a correlation between these defects and leakage current degradation. These findings indicate that peculiar basal plane dislocations associated with in-grown SFs may be critical contributors to I_DSX degradation, indicating the need for further research to elucidate the mechanisms behind this degradation in SiC-MOSFETs.

Abstract: In this study, high current stress was applied to the body diode of SiC-MOSFETs, and chips exhibiting leakage current degradation due to the bipolar degradation phenomenon were analyzed to identify the crystal defects responsible for the abnormal leakage current. Failure analysis and defect inspection during the device fabrication process revealed that abnormal leakage occurred at the periphery of extended stacking faults originating from or near the micropipe itself. As these extended stacking faults also increase the forward voltage drop of MOSFETs, these results suggest that micropipe are critical defects in SiC-MOSFETs inducing both forward voltage and leakage current degradation in the bipolar degradation phenomenon.

Abstract: Compressor valve spring failure and rapid fracture occurred in a petrochemical enterprise. To find the cause of the failure, and to ensure the safe, stable, and continuous operation of the device, the failure of the spring is analyzed. In this paper, through the macro inspection, chemical composition analysis, metallographic analysis, scanning electron microscopy analysis, energy spectrum analysis, hardness analysis, and other tests, it is concluded that the main reason for the spring fracture is the fatigue fracture caused by unqualified materials. Suggestions are given to avoid similar problems in the future, and it is hoped that this failure analysis will provide valuable experience for similar failure problems in petrochemical enterprises.

Abstract: Single Event Gate Rupture (SEGR) is one of the catastrophic failures caused by heavy ions in power MOS devices. In this study, n-type SiC MOS capacitors representing the gate structure generally used in SiC power MOSFETs were used to conduct heavy ion irradiation tests to clarify the SEGR mechanism. The Linear Energy Transfer (LET) dependence of the critical electric field (E_cr) for these capacitors was evaluated with two different oxidation processes in accumulation to confirm whether the oxidation process affects SEGR tolerance. We found that the E_cr value and slopes of the LET dependence for SEGR between DRY samples and DRY + POA samples were approximately consistent. We also simulated SEGR and studied its mechanism. The simulation results suggested that SEGR for SiC MOS capacitors is caused by carriers in electron-hole pairs generated by a heavy ion instead of gate electric field fluctuation.

Abstract: This paper describes a first attempt to build and operate a multi-chip prototype lander control and sensor signal digitization electronics circuit board comprised of ten NASA Glenn IC Generation 11 SiC JFET-R IC chips in 460 °C, 9.4 MPa harsh Venus surface conditions. The lander circuit ceased electrical operation prematurely at 107 °C as the Venus chamber heated up. Microscopic post-test inspections indicate that only one of the ten SiC chips on the board failed. Most of circuit-damaging cracks observed on the failed chip corresponded to micron-scale irregularly-shaped dielectric film hillock defects. The study of these defects suggests minor processing changes to eliminate this suspected root failure cause.

Abstract: The article discusses the failure analysis of the SDP-89 drill pipe nipple and provides an assessment of the material properties. The results of the analysis of the chemical composition and metallographic studies, as well as the mechanical properties of the material of the nipple parts of the drill pipe nipple are presented. As a result of measuring the hardness and performed mechanical tests, the heterogeneity of the mechanical properties over the section was established. As a result, it was found that the main cause of destruction is the microstructure inhomogeneity caused by the violation of the heat treatment.

Abstract: The crankshaft is one of the main components of the combustion engine used for continuous rotation. Therefore, this research aims to analyze the crankshaft failure of a jeep with a four-cylinder diesel engine used to transport 4 tons of logs on rugged terrain and uneven roads for 12 months. This research was carried out using the Scanning Electron Microscope (SEM), microstructure, hardness, chemical composition, and stress analysis testing methods. The chemical composition and microstructure test results showed that the crankshaft was made of AISI 3150 material with a pearlite phase. From the results of the visual observation on the fracture surface, the characteristics of failure due to fatigue are indicated by a beach mark pattern on the fracture surface. SEM test shows a crack initiation at the edge of the balancer due to the dynamic loads experienced by the crankshaft, which causes propagation from the initial beach marks pattern to the final fracture.

Abstract: Dealing with electronic devices for high reliability applications in terrestrial environments, neutron-induced Single Event Effects must be investigated. In this paper, the experimental observation of an atmospheric-like neutron-induced Single Event Burnout (SEB) on a packaged commercial SiC power MOSFET is presented after irradiation at ISIS-ChipIr. The effects of the SEB in the electrical properties of the MOSFET are established, and the SiC damaged zone is observed by scanning electron microscopy. Based on this failure analysis at the die level, the distinct stages during the SEB mechanism can be defined. The sensitive volume where the secondary particle deposited enough energy to trigger the SEB mechanism is identified and located inside the SiC n-drift epitaxial layer near the epitaxial layer/substrate junction.

Abstract: In this work, the H3TRB performance of power modules with SiC MOSFET chips is investigated and compared to their silicon counterparts with similar electrical ratings. For this purpose, SiC MOSFETs and silicon IGBT chips are packaged in the same housing and with the same packaging technology and an H3TRB test is performed on both types of test devices. The results show that while both types exhibit an excellent H3TRB performance, the SiC MOSFETs had a significantly longer time to failure but also a wider failure distribution. Hence, the investigations presented in this paper confirm that properly designed SiC devices feature an equal or even better ruggedness against electro-chemical stress than standard silicon devics and are equally suitable for applications, which require operation in harsh environments.

Abstract: Hot dip galvanizing can effectively prevent the corrosion of steel. With the increasing demand of industry for steel strip, higher requirements are put forward for stable and continuous operation of submerged roller bearings in hot dip galvanizing line. The existing sliding bearings for sink roll of galvanizing line mainly depend on imports, and their service life is about two weeks. Two weeks later, the sliding bearing failed, so it is necessary to stop the line and replace the new bearing, wasting a lot of material cost and time cost. In this paper, zinc liquid corrosion test, high temperature pin-and-disc dry friction test and corrosion wear test were carried out on the materials of sliding bearing pair of submerged roller, mainly alumina ceramic bushing and three kinds of metal sleeves (alloy A, alloy B and 316L stainless steel) under simulated actual working conditions. The status of corrosion and wear in bearing failure was compared and analyzed, and the hydrodynamic lubrication effect formed by zinc liquid under test conditions was considered, and the main failure mechanism was comprehensively analyzed.