Controlled Macrostepping of Si-Face 4°off 4H-SiC over a Large Area via Liquid Si-Induced Reconstruction

Abstract

The reconstruction of 4°off 4H-SiC surfaces was investigated using Si melting at 1550°C in a SiC/Si/SiC sandwich configuration. Despite systematically obtaining a macrostepped morphology over the entire areas in contact with the liquid Si, the steps were found wavy when using as-received 4H-SiC wafers. The regularity and straightness of the steps were significantly improved when the surface reconstruction was performed on processed surfaces: on re-polished surfaces the steps were found to be regular and straight in some cases, while this was constantly observed on as-grown epitaxial layers. After a reconstruction process of 2h, the best regularity of the steps was obtained with an average width of ̴ 3-5 μm. Increasing the processed area from 1.44 to 4 cm2 did not affect the results which suggests a good scalability of the process.