半导体功率器件输出电容动态本征能耗物理机理及模型研究

高频化是半导体功率器件的发展趋势之一，因其可以实现系统小型化。功率器件高频化的挑战是其动态功率损耗随频率增大而增大。最新研究表明，功率器件输出电容存在动态本征能量损耗，在硅超结、氮化镓和碳化硅器件中尤为突出，是新的功率损耗源。此能耗被认为与大信号输出电容滞回特性相关，但尚未有明确理论解释。申请人针对硅超结器件的研究显示，输出电容滞回特性与充放电过程中器件中性漂移区内载流子的运动规律有关。因此，本项目提出输出电容动态本征能耗来源于载流子在高阻区内运动。本项目拟以功率场效应晶体管和肖特基二极管为研究对象，从载流子运动规律入手，借助器件仿真和实验测量，分析器件内部耗尽区变化趋势和电热作用微观过程，揭示输出电容动态本征能耗物理机理，评估高频开关性能，提出优化设计原则，建立等效电路模型。本项目成果对于进一步认识功率器件工作原理、丰富器件知识具有重要学术价值，对于提高功率器件的工作频率具有重要意义。

High frequency is one of the development trends of semiconductor power devices because it can realize miniaturization of the system. The challenge of high frequency switching of power devices is that its dynamic power loss increases with increasing frequency. Recent researches show that the output capacitance of power devices has a dynamic intrinsic energy loss, which is a new source of the power loss. The phenomenon is particularly prominent in silicon superjunction, gallium nitride and silicon carbide devices. This energy loss is considered to be related to the hysteresis characteristic of the large-signal output capacitance. But there is no clear theoretical explanation. Our study on the silicon superjunction device shows that the hysteresis characteristic of the output capacitor is related to the carrier dynamics in the neutral drift region of the device during the process of charging and discharging. Therefore, this project proposes that the dynamic intrinsic energy loss of the output capacitance is generated by carriers moving in the high impedance region. This project will choose power field effect transistors and Schottky diodes as research subjects. Starting from carrier dynamics, the changing trend of the depletion region and the micro electrothermal process will be analyzed with the help of the device simulation and the experimental measurement. The purpose of this project is to reveal the physical mechanism of the intrinsic dynamic energy loss of the output capacitance, to evaluate the high-frequency performance, to propose principles of optimal design and the equivalent circuit model. The results of this project carry important academic values to further understand the principle of power devices and to enrich the device knowledge. They also carry great significance to improve the frequency of power devices.