Schottky barrier diode (SBD)-embedded SiC MOSFETs can clamp the parasitic p-n diode that causes a lack of long-term stability and thus realize high reliability. However, the maximum current density at which the parasitic p-n diode does not operate ( Jumax{J}_{\text{umax}} ) decreases with increasing temperature. Therefore, further improvement of Jumax{J}_{\text{umax}} and understanding the mechanism of the temperature dependence of Jumax{J}_{\text{umax}} are urgent issues. We have developed an equivalent circuit model of SBD-embedded SiC MOSFETs and derived an analytical formula of Jumax{J}_{\text{umax}} . Based on the derived analytical formula of Jumax{J}_{\text{umax}} , we have proposed guidelines for improving Jumax{J}_{\text{umax}} . Then, utilizing the guidelines, we have tried to improve Jumax{J}_{\text{umax}} experimentally. As a result, Jumax{J}_{\text{umax}} of 3.3 kV SBD-embedded SiC MOSFETs has been improved by 3.8 times. In addition, the mechanisms by which Jumax{J}_{\text{umax}} decreases in high blocking voltage devices and at high temperature have been investigated. We have found that the blocking voltage dependence of Jumax{J}_{\text{umax}} is caused by the change in the current distribution due to the difference in the drift resistance. On the other hand, it has also been confirmed that the decrease in Jumax{J}_{\text{umax}} is not necessarily a problem because the rated current density also decreases in high blocking voltage devices. From the partial differentiation of Jumax{J}_{\text{umax}} ’s analytical formula with respect to temperature, it has been clarified that the decrease in Jumax{J}_{\text{umax}} is mainly due to the increase in the spread resistance and the JBS resistance.

中文翻译：

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SBD 嵌入式 SiC MOSFET 中寄生 pn 二极管的钳位能力


内置肖特基势垒二极管 (SBD) 的 SiC MOSFET 可以钳位导致缺乏长期稳定性的寄生 pn 二极管，从而实现高可靠性。然而，寄生 pn 二极管不工作的最大电流密度 ( Jumax{J}_{\text{umax}} ) 随着温度的升高而降低。因此，进一步改进Jumax{J}_{\text{umax}}并了解Jumax{J}_{\text{umax}}的温度依赖性机制是紧迫的问题。我们建立了 SBD 嵌入式 SiC MOSFET 的等效电路模型，并推导了 Jumax{J}_{\text{umax}} 的解析公式。基于导出的 Jumax{J}_{\text{umax}} 解析公式，我们提出了改进 Jumax{J}_{\text{umax}} 的指南。然后，利用这些指南，我们尝试通过实验改进 Jumax{J}_{\text{umax}}。结果，3.3 kV SBD 嵌入式 SiC MOSFET 的 Jumax{J}_{\text{umax}} 提高了 3.8 倍。此外，还研究了 Jumax{J}_{\text{umax}} 在高阻断电压器件和高温下降低的机制。我们发现Jumax{J}_{\text{umax}}的阻断电压依赖性是由于漂移电阻的差异导致电流分布的变化引起的。另一方面，也已证实Jumax{J}_{\text{umax}}的降低不一定是问题，因为在高阻断电压器件中额定电流密度也会降低。从 Jumax{J}_{\text{umax}} 的解析式对温度的偏微分可知，Jumax{J}_{\text{umax}} 的下降主要是由于价差阻力和 JBS 阻力的增加。