Effects of As cell temperature on oval defect density and C acceptor concentration of light Si-doped GaAs grown by molecular beam epitaxy

We report the correlation between As effusion cell temperature and residual CO vapor intensity, oval defect density, C acceptor concentration and electrical properties of GaAs layers grown by molecular beam epitaxy. The As cell is found to be one of the sources of CO vapor. The oval defect density on GaAs surfaces and C acceptors incorporated into the material are directly proportional to the residual CO vapor intensity. We suggest that the reaction between Ga and CO vapor on the hot Ga cell surface may be responsible for the formation of oval defects, and the C generated from this reaction may enhance C acceptor concentration of the grown GaAs material.