平面梯形栅GaN HEMT功率器件横向电场击穿特性分析

With the development in the field of power electronics, power devices, as the key components in the energy storage system, are gradually moving towards high frequency, high power, low power consumption as well as miniaturization. For transverse AlGaN/GaN devices, the edge-concentration effect of the gate electric field restricts the improvement of the breakdown voltage of AlGaN/GaN HEMT devices. In this paper, TCAD software is used to simulate and analyze the electric field distribution and breakdown characteristics of trapezoidal and rectangular gates under transverse electric field, and the simulation results show that the peak electric field position at breakdown is located at the position of P-GaN near the gate, and the breakdown electric field strength is the largest when the trapezoidal gate is 97 degrees, and the introduction of multiple peaks of the electric field at the trapezoidal sidewalls improves the concentration of the electric field of the rectangular gate in the transverse electric field. When exceeding 97degrees, the maximum breakdown electric field strength is reduced due to the decrease in the lateral depletion region as the trapezoidal angle increases, which causes a decrease in the maximum breakdown electric field strength. As the pitch decreases, the depletion region continues to broaden and the transverse breakdown electric field gradually increases, and the breakdown voltage is maximum when the trapezoidal gate pitch is 0.5μm. As the length of P-GaN increases, the breakdown voltage increases and then decreases, and the breakdown voltage is maximum when the length is 2μm. When the length exceeds 2 μm, the transverse electric field increases at the position close to the gate, resulting in a decrease in the transverse breakdown voltage and an early breakdown of the device.