基于场制固化及电荷俘获的低损耗高线性Si基GaN增强型射频功率器件研究

面向电源调制器、5G射频前端组件对GaN增强型射频功率器件的需求，本项目将针对低射频损耗Si基GaN外延设计与生长技术，电荷俘获型增强型器件结构及线性度提升展开研究，实现高性能Si基GaN增强型射频功率器件的研制。探索Si基GaN外延材料的射频损耗来源，建立包含衬底、界面寄生沟道等特征损耗参数的等效电路模型，并采用低温脉冲法成核层生长技术降低射频损耗；基于电荷俘获技术实现对沟道载流子的无损调制，解决增强型器件高驱动与高阈值的矛盾问题，并结合准范德华外延理论与超低损伤热剥离技术，实现对俘获电荷的固化，解决其阈值稳定性问题；基于能带势阱调制载流子输运理论，采用两步法复合沟道生长方式，提升Si基GaN增强型器件的线性度。本项目在高性能Si基GaN增强型射频功率器件方面的研究具有重要科学意义，将拓宽GaN基增强型器件的应用领域，为手机终端等多功能微型系统的高度模组化、集成化提供有力的技术支撑。

For the demand of power supply modulator and RF Front-end for GaN-based normally-off devices, the project will focus on the design and growth technology of low-loss Si-based GaN epitaxial structure, the structure design and linearity improvement of charge trapping normally-off devices, so as to realize high performance Si-based GaN normally-off RF power devices. In this project, the equivalent circuit model including substrate, interface parasitic channels and other characteristic parameters accounting for RF Loss is built to explore its essential source, and a new nucleation growth technology achieved by low temperature pulse method is adopted to reduce RF Loss. Based on the technique of charge trapping, the lossless modulation of channel carriers is realized to resolve the principal contradiction between high threshold voltage (Vth) and strong drive ability in traditional GaN-based normally-off devices. In addition, the quasi Van Der Waals extension theory and the ultra-low damage thermal stripping technology are combined to realize the stabilization of the trapped charge and resolve the reliability issue of Vth stability for charge trapping devices. Utilizing the theory of energy band modulation and potential well storage, a two-step composite channel growth technology is adopted to improve the linearity of Si-based GaN normally-off devices. As a whole, the project has essential scientific significance in the research of high performance Si-based GaN normally-off devices, which will broaden the applications of GaN-based normally-off devices, and provide strong technical support for the highly modularization and integration for multi-functional microsystems especially the mobile terminals.