A Study on Graphitization of 4H-SiC(0001) Surface under Low Pressure Oxygen Atmosphere and Effects of Pre-Oxidation Treatment

Abstract

Effects of residual oxygen in an annealing chamber on graphitization of SiC along with surface pre-treatment process have been investigated. As a pre-treatment process, SiO2 was formed on 4H-SiC(0001) substrates by thermal oxidation before graphene formation annealing. Epitaxial graphenes were formed in several O2 pressures and effects on graphitization of SiC were evaluated. It is shown that quality of graphene on SiC substrates which formed without pre-oxidation degraded by the presence of residual O2 in the chamber. It is demonstrated that SiO2 pre-oxidation films (about 10nm) were effective to prevent such degradations, for all O2 pressures that we examined in this work. In addition, at O2 pressure of 1.1x10-1Pa, with SiO2 pre-oxidation, a graphene growth rate was increased, which indicates that a certain level of O2 pressure enhances graphene growth.