Quantum chemical calculations of sulfur doping reactions in diamond CVD

Recently, n-type semiconducting diamond was successfully obtained by sulfur doping using CH4/H2S/H-2 plasma chemical vapor deposition (CVD). It was reported that the crystal quality too was improved by the sulfur doping. In this study, the equilibrium geometry and the band structure of S- and O-doped diamond have been investigated using density function theory (DFT) calculations. Moreover, the sulfur incorporation mechanisms have been investigated by the semi-empirical molecular orbital (MO) calculations. Our calculations revealed that the sulfur atoms are spontaneously incorporated into the diamond (100) surface, while the incorporation of the oxygen atoms is unfavorable.