Investigation of the bipolar degradation of SiC MOSFET body diodes and the influence of current density

Palanisamy, Shanmuganathan; Basler, Thomas; Lutz, Josef; Künzel, Cesare; Wehrhahn-Kilian, Larissa; Elpelt, Rudolf

doi:10.1109/irps46558.2021.9405183

Cited by 15 publications

(5 citation statements)

References 15 publications

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“…Even in lower voltage classes like 1.2 kV SiC MOSFETs, there can be higher drifts observed under extreme current stress conditions. The degradation, observed from the results presented in this paper, is not occurring due to a package or a bond-wires (thermomechanical) damage as reported by [8] but by stacking faults expansion. In the case of high current density of 1700 A/cm 2 , the hole density increases significantly in the border region between the epi and substrate, where carrier recombination occur and causes SF expansion, which is corelating to the findings of bar-shaped stacking faults from the post-analysis.…”

Section: Experimental Analysissupporting

confidence: 62%

Pulsed Forward Bias Body Diode Stress of 1200 v SiC MOSFETs with Individual Mapping of Basal Plane Dislocations

Kochoska

Pham

Maslougkas

et al. 2023

MSF

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Bipolar degradation is a known problem in the development of SiC MOSFETs when the body diodes (p+ body/ n-drift layer) are forward biased. Mostly higher voltage classes like the 1.7 kV or 3.3 kV SiC MOSFETs have been studied in literature resulting with significant Rdson increase [1-2]. In this work, body diode stress was conducted for 1.2kV SiC MOSFETs, which were mapped with Infra-Red photoluminescence (IR-PL) to determine and localize the exact number of BPDs present in the drift layers of each die [3, 4] and grouped by this criterion. Devices were stressed at extremely high current densities (1200 – 1700 A/cm2) under pulsed conditions. The post-stress analysis shows non-negligible increase of Rdson and Vf. Bipolar degradation occurring from stressing the body diodes at high forward current densities was confirmed by electroluminescence analysis.

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Section: Experimental Analysissupporting

confidence: 62%

Pulsed Forward Bias Body Diode Stress of 1200 v SiC MOSFETs with Individual Mapping of Basal Plane Dislocations

Kochoska

Pham

Maslougkas

et al. 2023

MSF

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“…As shown in figure 12, the spatial distributions of the EL intensity based on the chip backside of the samples are obtained with V gs = −10 V and I ds = −10 mA. It is apparent that the EL intensity of each sample is almost uniform and no triangularshaped SF [28,29] can be found in the aged samples, which indicates that the bipolar degradation (i.e. body diode degradation) has not occurred here.…”

Section: Further Degradation Analysismentioning

confidence: 98%

Degradation mechanism analysis for SiC power MOSFETs under repetitive power cycling stress

Rao¹,

Chen²,

He³

et al. 2021

J. Phys. D: Appl. Phys.

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In this work, investigation on the degradation behavior of 1.2 kV/52 A silicon carbide (SiC) power MOSFETs subjected to repetitive slow power cycling stress has been performed. Electric characteristics have been characterized periodically over the stress and the respective degradation mechanisms have also been analyzed. A comprehensive degradation analysis is further conducted after the aging test by virtue of the x-ray inspection system, scanning acoustic microscope, scanning electron microscope, emission microscope, etc. Experimental results reveal that both the degradation of the gate oxide on the chip-level and the degradation of the bond wire and solder layer on the package-level have emerged over the cyclic stress. Specifically, growths of threshold voltage (V th) and gate leakage current (I gss) are thought to be relevant with the degradation of gate oxide by SiC/SiO2 interface states trapping/de-trapping electrons on the chip-level, while the appearance of fatigue in the bond wire and the delamination of the solder layer imply the degradation on the package-level. This work may provide some practical guidelines for assessments of the reliability of SiC power MOSFETs in power conversion systems.

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“…The advantages and disadvantages of IGBTs and MOSFETs are highlighted in Table 2. High cost [138] Low cost Low switching frequency required Improved thermal properties [162] Forward voltage degradation [163] Can withstand high short circuit currents Cannot block high reverse voltages Higher voltage blocking [164] Reliability issues Low driving power [165] Generally unidirectional Fast response [84] 5. Protection…”

Section: Igbt and Mosfetsmentioning

confidence: 99%

Review of MVDC Applications, Technologies, and Future Prospects

Coffey

Timmers

et al. 2021

Energies

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This paper presents a complete review of MVDC applications and their required technologies. Four main MVDC applications were investigated: rail, shipboard systems, distribution grids, and offshore collection systems. For each application, the voltage and power levels, grid structures, converter topologies, and protection and control structure were reviewed. Case studies of the varying applications as well as the literature were analyzed to ascertain the common trends and to review suggested future topologies. For rail, ship, and distribution systems, the technology and ability to implement MVDC grids is available, and there are already a number of case studies. Offshore wind collection systems, however, are yet able to be implemented. Across the four applications, the MVDC voltages ranged from 5–50 kV DC and tens of MW, with some papers suggesting an upper limit of 100 kV DC and hundreds of MV for distribution networks and offshore wind farm applications. This enables the use of varying technologies at both the lower and high voltage ranges, giving flexibility in the choice of topology that is required required.

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Investigation of the bipolar degradation of SiC MOSFET body diodes and the influence of current density

Cited by 15 publications

References 15 publications

Pulsed Forward Bias Body Diode Stress of 1200 v SiC MOSFETs with Individual Mapping of Basal Plane Dislocations

Pulsed Forward Bias Body Diode Stress of 1200 v SiC MOSFETs with Individual Mapping of Basal Plane Dislocations

Degradation mechanism analysis for SiC power MOSFETs under repetitive power cycling stress

Review of MVDC Applications, Technologies, and Future Prospects

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