Deng Hui, Endo Katsuyoshi, Yamamura Kazuya
Research Center for Ultra-precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Sci Rep. 2015 Mar 10;5:8947. doi: 10.1038/srep08947.
The surface atomic step-terrace structure of 4H-SiC greatly affects its performance in power device applications. On the basis of the crystal structure of 4H-SiC, we propose the generation mechanism of the a-b-a*-b* type, a-b type and a-a type step-terrace structures. We demonstrate that the step-terrace structure of SiC can be controlled by adjusting the balance between chemical modification and physical removal in CeO2 slurry polishing. When chemical modification plays the main role in the polishing of SiC, the a-b-a*-b* type step-terrace structure can be generated. When the roles of physical removal and chemical modification have similar importance, the a-b-a*-b* type step-terrace structure changes to the a-b type. When physical removal is dominant, the uniform a-a type step-terrace structure can be generated.
4H-SiC的表面原子台阶-平台结构极大地影响其在功率器件应用中的性能。基于4H-SiC的晶体结构，我们提出了a-b-a*-b型、a-b型和a-a型台阶-平台结构的生成机制。我们证明，通过调整CeO2浆料抛光中化学改性与物理去除之间的平衡，可以控制SiC的台阶-平台结构。当化学改性在SiC抛光中起主要作用时，可以生成a-b-a-b型台阶-平台结构。当物理去除和化学改性的作用具有相似的重要性时，a-b-a-b*型台阶-平台结构转变为a-b型。当物理去除占主导时，可以生成均匀的a-a型台阶-平台结构。
