基于热氧化“Si/AlN叠层”的SiC MOS界面态抑制方法研究

作为性能优越的新一代电力电子器件，SiC MOSFET已在新能源等领域得到初步应用。然而SiC MOS结构较高的界面态密度造成较差的反型层迁移率与栅氧可靠性，致使SiC MOSFET的技术升级与规模应用受到严重阻碍。大量研究表明SiC氧化过程中产生的碳团簇是SiC MOS界面退化的主要原因，但相关的氧化机制与钝化机制尚不清晰，目前仍缺乏有效抑制碳团簇的方法。针对以上问题，本项目提出热氧化“Si/AlN叠层”的栅氧制备新思路，引入与SiC晶格匹配的AlN为Si热氧化工艺的缓冲层，极大避免栅氧制备过程中SiC的热氧化，有助于从根本上抑制碳团簇的产生。此外，AlN氧化产生的氮气将在不额外引入退火工艺的情况下实现界面钝化，有望进一步改善SiC MOS界面。本项目将基于此研究思路展开机理性与实验性研究，以期突破SiC栅氧的瓶颈问题，为实现高品质的SiC MOS结构提供新的思路与方法。

As a new generation of power electronic devices with superior performance, SiC MOSFET products have been initially applied in new energy and other fields. However, the high interface state density of SiC MOS structure leads to low carrier mobility and bad gate oxide reliability, which severely limits the technology upgrading and industrial application of the SiC MOSFET. A large number of studies have shown that the carbon clusters generated in the process of SiC thermal oxidation are the main reason for the high interface state density of SiC MOS structure, however, there is still a lack of effective methods to suppress the carbon clusters due to the unclear oxidation mechanism and passivation mechanism. To solve the interface problem of SiC MOS structure, this project put forwards a new gate oxide preparation technology based on the thermal oxidation of "Si/AlN stack layer". AlN matched with SiC lattice is used as a buffer layer of the thermal oxidation process to suppress carbon clusters produced in SiC thermal oxidation. Additionally, the nitrogen generated during oxidation of AlN can passivate the AlN/SiC without introducing post-oxidation-annealing process, further improving the SiC MOS interface. Through theoretical and experimental research, this project aims to break through the bottleneck problem of SiC gate oxide preparation, providing a new idea and solution to realize high quality SiC MOS structure.