Diamond films produced by microwave plasma chemical vapor deposition at low temperature and their characterization

Diamond films were deposited using in CH4/Ar/H2 gas system and silicon(1 1 1) wafers as substrate in microwave plasma chemical vapor deposition at low temperature of about 350 °C. The effects of the gas system and layout, different microwave power, and different pretreatment methods of substrate on the microstructure of diamond films are discussed. The diamond film samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that diamond (1 1 1) Bragg peak of XRD patterns is very weak because of the presence of a non-diamond phase and defects. The SEM images show that diamond films are stacked with regularly arranged and about 200 nm base ball-like diamond secondary nucleation particles. The diamond films consist of particles that are not well-faceted.