Surface preparation of [formula omitted]-SiC for the epitaxial growth of 3C–SiC

Abstract

In this paper, we present a study of the surface preparation of on-axis, Si face 6H–SiC(0 0 0 1) and 4H–SiC(0 0 0 1) substrates for the growth of 3C–SiC heteroepitaxial layers. The treatments were performed in a vertical cold-wall reactor, at temperatures ranging from 1350 to 1650 °C for 10–30 min, under H 2 or H 2+C 3H 8 atmospheres. By atomic force microscopy investigation, the 4H–SiC surfaces were always found to be rougher than the 6H–SiC ones so that we mainly studied the use of 6H–SiC. All the samples displayed a more or less regular surface covered with small steps (up to 1 nm height). Si droplet formation was observed in some specific conditions, which, hence, are to be avoided. The most regular array of steps (∼0.7 nm height) was obtained on 6H–SiC seeds under H 2 treatment at 1450 °C for 10 min. On such surfaces, 3C–SiC growth was performed using a mixture of SiH 4+C 3H 8 at 1450 °C with a C/Si ratio of 3 in the gas phase.