P-grid is a typical feature in power devices to block high off-state voltage. In power devices, the p-grid is routinely coupled to an external electrode with an Ohmic contact, but Schottky contact to the p-grid is also proposed/adopted for certain purposes. This work investigates the role of contact to p-grid in power devices based on the commonly adopted technology computer-aided design (TCAD) device simulations, with the silicon carbide (SiC) junction barrier Schottky (JBS) diode as a case study. The static characteristics of the JBS diode is independent of the nature of the contact to p-grid, including the forward voltage drop (V_F) and the breakdown voltage (BV). However, during the switching process, a Schottky contact would cause storage of negative charges in the p-grid, which leads to an increased V_F during switching operation. On the contrary, an Ohmic contact provides an effective discharging path for the stored negative charges in the p-grid, which eliminates the dynamic degradation issues. Therefore, the necessity of an Ohmic contact to p-grid in power devices is clarified.

中文翻译：

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基于电荷存储效应和动态退化的SiC功率器件p栅电触点研究

P电网是功率器件中的典型功能，用于阻止高关断状态电压。在功率器件中，p-网格通常通过欧姆接触与外部电极耦合，但是出于某些目的，也建议/采用了肖特基与p-网格的接触。这项工作基于常用技术计算机辅助设计（TCAD）器件仿真，以碳化硅（SiC）结势垒肖特基（JBS）二极管为案例，研究了功率器件中p-grid接触的作用。JBS二极管的静态特性与p电网的触点性质无关，包括正向压降（V _F）和击穿电压（BV））。但是，在开关过程中，肖特基接触会导致p电网中存储负电荷，这会导致开关操作期间的V _F增大。相反，欧姆接触为p网格中存储的负电荷提供了有效的放电路径，从而消除了动态退化问题。因此，明确了在功率器件中欧姆接触到p栅极的必要性。