垂直型氮化镓功率MOSFET新结构与沟道特性机理研究

垂直型氮化镓（GaN-on-GaN）功率MOSFET可突破平面型GaN-on-Si功率开关管在耐压和功率等级等方面的限制，是高效高功率密度电力电子器件研究的前沿课题之一。针对当前垂直型沟槽结构GaN-on-GaN功率MOSFET沟道电阻较高和阈值调控机制不清的问题，本项目以III族氮化物独特的极化电荷为出发点，提出基于界面电荷调控（ICM）机制的垂直型GaN MOSFET新结构，重点开展以下研究：（1）揭示基于极化电荷的新型界面优化方法对载流子迁移率和沟道性能的影响机理，为高效GaN MOSFET导通电阻的降低开辟新途径；（2）探明斜栅刻蚀和界面工艺对沟槽结构MOSFET界面电荷的影响规律，为常关型沟槽结构GaN MOSFET的阈值调控提供理论指导。本项目预期实现具有理想阈值电压、优异沟道性能的1.2kV~1.7kV垂直型GaN功率MOSFET，为通态性能的提升和优化奠定理论基础。

Vertical GaN-on-GaN power MOSFET is capable of breaking the voltage and power rating limit of lateral GaN-on-Si power transistor, and has been recognized as one of the cutting-edge research topics toward high-efficiency and high-power-density devices. Nevertheless, vertical trench GaN-on-GaN power MOSFET is currently confronted with the key challenges of realizing reduced channel resistance and effective threshold voltage modulation. Aiming at tackling these issues, this project proposes a novel vertical GaN MOSFET structure based on the interface charge modulation (ICM) concept, and systematically investigates device mechanisms including: (1) To reveal the underlying mechanism of the polarization-charge-based interface optimization in influencing the carrier mobility and channel performance, which is critical for channel resistance reduction; (2) To reveal the impact of the slanted gate trench formation and interface engineering process on the interface charge distribution, which can provide guideline for the realization of normally-off GaN trench MOSFET with desirable threshold voltage. With the theoretical and experimental studies in this project, 1.2kV~1.7kV vertical GaN power MOSFETs with desirable threshold voltage and enhanced channel performance will be realized, which is also valuable for further optimization of the on-state performance in vertical GaN power MOSFET.