2022 Fiscal Year Annual Research Report
Development of reliable SiC MOSFET power modules
| Project/Area Number |
21H01311
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| Research Institution | Osaka University |
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Principal Investigator |
舟木 剛 大阪大学, 大学院工学研究科, 教授 (20263220)
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| Co-Investigator(Kenkyū-buntansha) |
カステッラッズィ アルベルト 京都先端科学大学, 工学部, 教授 (70866897)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | Reliability / multi-chip power modules / SiC power MOSFETs / electrothermal model / thermal resistance |
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| Outline of Annual Research Achievements |
SiC power MOSFETs are enablers of disruptive progress beyond state-of-the-art in the key parameters of power electronics technology evolution: efficiency, power density and reliability. Specifically, their ability to be operated at higher switching speeds, higher switching frequencies and ambient temperatures has been shown to yield important system level benefits, even when transistors are used as a drop-in replacement of Si ones. Still, full exploitation of the superior features of wide-band-gap devices and their subsequent large volume deployment is conditional to the development of bespoke technological solutions and design options, including cooling and packaging, as well as design tools and validation methodologies. This year, the proposer developed reliability evaluation setup which simultaneously performs accelerated deterioration of SiC power MOSFET and evaluated the lifetime of key electrical power conversion applications. Because of intrinsic differences with the established silicon technology, the test evaluated SiC-bespoke design and validated its effect on device reliability. This work assessed the state-of-the-art in electro-thermal parameters spread for both planar-gate and trench-gate type SiC MOSFET. Based on the transient thermal resistance characterization experimented results, physical eletro-thermal simulation model was developed, which enabled to investigate the relation between device progressive degradation patterns and the initial parameters value spread.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
A number of commercial devices from different manufacturers, voltage ratings, on-state resistance and gate technologies were selected and tested with the developed acceleration degradation test system, which enabled to assess simultaneously multiple devices. Characteristics change results are observed for the threshold voltage, Vth, and the on-state resistance, Rdson. Characteristics spread for respective type SiC MOSFET were evaluated statistically. We developed electro-thermal compact models describing all major physical effects and behavioral features with characterizing the transient thermal resistance. The transient electro thermal model of SiC MOSFET enabled to simulate multi-chip structures power module. The chip layout and package-related parasitic elements are extracted from switching test of the device. The developed device models is suitable for analysis of very diverse time scales, ranging from hundreds of ns for switching operation up to several tens of ms for thermal response.
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| Strategy for Future Research Activity |
Future work aims to provide experimental results of deterioration of SiC MOSFET for the acceleration test and clarifies the mechanism in degradation progression and spread in the main electro-thermal parameters value. The mechanism of degradation and their distribution in characteristics helps to design power module, and it gives lifetime assessment. It also enables to design competitive hardware, even in presence of higher operational temperature and loss of acceleration factor with established technology validation approaches. The transient thermal resistance behavior gives structure function as electro thermal model, whose differential and cumulative structure-functions gives a physical model to represent the structural characteristics of a power module based on its thermal response.
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