SiC MOS器件近界面氧化物缺陷与阈值电压漂移抑制技术研究

Silicon carbide (SiC) is a wide bandgap semiconductor with excellent performance for high temperature, high power, and high frequency electronic devices. Therefore, power devices based on SiC is very popular..Threshold voltage shift in SiC MOSFETs by traditional process is a serious issue, which is due to a large number of active defects in near SiC/SiO2 interface at the oxide. Hence, the problems of near-interface oxide traps (NIOTs) and threshold voltage shift become the key issue of SiC MOS devices and need to be addressed urgently..In the proposal, we will develop oxidation technology and interface defects passivation technology by electron cyclotron resonance microwave plasma system with low energy, highly ionized, highly dense, and highly reactive plasma to improve oxidation and passivation efficiency. These technologies can avoid the generation of new defects and achieve the goal of reducing the oxide defects near the interface. Electrical characteristics of MOS devices are analyzed for obtaining the threshold voltage shift and density of near-interface oxide traps. At the same time, the methods of physicochemical analysis technique and computational materials science, such as XPS, SIMS and HRTEM, are used for investigating the physical mechanism of formation, activation, and passivation of defects in actual oxidation process. The essential relationships between threshold voltage shift and the composition and structure of near interface oxide defects as well as the process of oxidation and passivation are clarified. This proposal provides a reference for improving the manufacturing process in practical SiC MOS devices.

第三代半导体碳化硅（SiC）是一种性能优异的宽禁带半导体材料，基于碳化硅的功率电子器件研究备受关注。.传统工艺制作的SiC MOSFET存在阈值电压漂移的严重问题，这很大程度上归因于氧化层近界面区域中存在的大量活性缺陷。因此，近界面氧化物缺陷与阈值电压漂移问题成为SiC MOS器件研究迫切需要解决的关键科学问题。.本申请拟自主开发电子回旋共振氧化技术和界面缺陷钝化技术，通过超低损伤、高密度和高活性的氧等离子体提高氧化和钝化效率，避免新生缺陷，进而达到降低近界面氧化物缺陷的目的。同时，利用电学特性分析器件的阈值电压漂移及近界面陷阱密度参数，结合XPS、SIMS和HRTEM等理化分析技术及计算材料学方法，研究真实氧化过程中缺陷的形成、激活及钝化的物理机制，明晰阈值电压漂移与近界面氧化物缺陷组成、结构、氧化钝化工艺间的本质关系，为改善实际SiC MOS器件制造工艺提供参考依据。

第三代半导体SiC电力电子器件能够提升电力装备系统效率、减少系统能耗和装置的体积和重量、提高系统可靠性，对我国轨道交通、新能源汽车和超高压电网等战略产业发展具有重要意义。.针对SiC MOSFET器件中存在的阈值电压漂移问题，基于栅氧界面缺陷研究，开展了臭氧氧化和多元钝化等新技术探索，突破了器件物理参数测试和可靠性制造技术难题，形成了栅氧可靠性制造及可靠性劣化分析的成套解决方案，形成多项自主知识产权和国际顶级原创成果。.该项目为解决和改善制造端器件可靠性问题提供了全面的理论和技术支撑，可望通过技术转化和技术服务为推动解决行业中的器件可靠性制造问题发挥作用。