This article focuses on the avalanche energy handing ability and theoretical demonstration of the avalanche failure mechanism for the SiC MOSFET by the unclamped inductive switching (UIS) test, the mathematical model, and the numerical simulation. Two evaluation methods are implemented to understand the effect of the avalanche current density and the avalanche energy on the device failure with the ambient temperature ranging from 300 to 450 K. Moreover, the thermodynamic model based on the thermal diffusion equation is developed to explore the critical temperature limitation. The avalanche capability highly depends on the dimension parameters and premature degradation points. The numerical simulation with the multicells and the real device parameters is used to reveal the electric performances of the SiC MOSFET during the UIS for the first time. At the same time, the temperatures in the SiC lattice and the metal system are precisely separated by the numerical method. The experimental results and simulation study demonstrate that the molten metal system on the surface of the SiC MOSFET induced by the local high temperature is prone to generate the thermal stresses and damage the device during the UIS transient. This failure mechanism is perfectly supported by the experimental, modeling, and numerical results.

中文翻译：

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4H-SiC MOSFET非钳位感应开关过程中温度极限的实验和理论证明

本文通过未钳位电感开关（UIS）测试，数学模型和数值模拟，重点研究了SiC MOSFET的雪崩能量处理能力和理论证明。实施了两种评估方法以了解雪崩电流密度和雪崩能量对环境温度在300至450 K范围内的器件故障的影响。此外，建立了基于热扩散方程的热力学模型以探索临界温度。温度限制。雪崩能力高度取决于尺寸参数和过早降解点。利用多单元和实际器件参数进行的数值模拟首次揭示了UIS期间SiC MOSFET的电性能。同时，SiC晶格和金属系统中的温度通过数值方法精确分离。实验结果和仿真研究表明，局部高温引起的SiC MOSFET表面的熔融金属体系在UIS瞬变期间易于产生热应力并损坏器件。实验，建模和数值结果完美地支持了这种失效机制。