Epitaxial growth of SiC-heterostructures on α-SiC(0001) by solid-source MBE

Abstract

Epitaxial growth of SiC on α-SiC(0001) has been performed by means of solid-source molecular beam epitaxy (MBE). Low temperature ( T<1200°C) deposition on on-axis SiC substrates always results in the growth of 3C-SiC, which is significantly improved by an alternating supply of Si and C. On vicinal substrates, a step flow growth mode has been realized at T down to 1050°C. In experiments performed at T>1200°C, with a step decrease of supersaturation, a step-flow growth mode and for the first time nucleation of both 4H- and 6H-SiC under C-rich conditions was obtained. Based on these results we have demonstrated the growth of a double-heterostructure by firstly growing a 3C-SiC film on 4H-SiC(0001) at low temperature and a subsequent growth of 4H-SiC at low supersaturation on a C-stabilized surface on top of this film. Moreover, we also propose a new model to explain quantitatively the occurrence of different growth features and polytypes under certain growth conditions.