Oxygen plasma pre-treatments for high quality homoepitaxial CVD diamond deposition

Abstract

In this study, homoepitaxial diamond films were grown on HPHT Ib synthetic diamonds by microwave plasma assisted CVD (MWPACVD) using a two step process. Etching of the diamond substrates prior to growth was performed in oxygen-hydrogen or oxygen-argon-hydrogen plasmas for different etching times. After this step, homoepitaxial growth was performed for 20 hours. High quality monocrystalline diamond films have been synthesized as confirmed by Raman and photoluminescence spectra and growth rates close to 2.5 μm/h have been achieved. This relatively high growth rate opens the way to the synthesis of thick, high quality single crystal specimens for high-power electronic applications. Optical and Atomic Force Microscopy (AFM) were performed after each step. These analyses showed that aggressive etching with oxygen not only reveals the defects on the top of the diamonds but also leads to a better quality of the homoepitaxial film by preparing the substrate surface before the deposition. We also confirmed that the final morphology of the homoepitaxial film is highly dependent on the quality of the initial diamond substrate. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)