The effect of substrate bias voltage on nucleation of diamond crystals in a microwave plasma assisted CVD process

Diamond films were deposited by microwave plasma chemical vapor deposition onto single-crystal (111), (110) and (100) silicon wafers. The deposition was preceded by an in situ bias pretreatment to enhance the nucleation. The effects of this substrate bias voltage on the nucleation density, orientation of the nuclei, and crystal quality of the diamond films were investigated. The influence of the hydrocarbon fraction of the gas mixture and the substrate temperature on the diamond nucleation under constant bias voltage was also studied.