Effects of Oxygen Addition on Diamond Film Growth by Electron-Cyclotron-Resonance Microwave Plasma CVD Apparatus

Abstract

Diamond thin films have been grown by an electron-cyclotron-resonance (ECR) microwave plasma chemical vapor deposition (CVD) apparatus under the addition of oxygen to the host ambient gas of a mixture of CO and H2 gas. Although the amount of oxygen was very minute (0-6% vol. fraction), significant changes due to the oxygen were brought about in the growth properties and the film crystallinity. The Raman spectroscopy revealed a dramatically improved film crystallinity and the film was dominated by the grain growth, resulting in the faceted morphology. With increase in the oxygen up to 4.55%, the visible cathodeluminescence (CL) intensity grew by more than ten times. However, the CL spectrum indicated an appearance of one or two extra recombination centers depending on the amount of oxygen.

Theoretical Study of the Thermodynamic and Kinetic Aspects of Terminated (111) Diamond Surfaces

“…Induced p-type doping of the (100) surface has been shown to be lost upon oxygenation, whereas a smooth oxygenated (111) surface remains conductive . Furthermore, atomic oxygen may contribute to a favorable sp 3 hybridization of carbon and to minimizing graphite-like sp 2 hybridization due to CO desorption. − The resulting termination scenario of an oxygenated diamond surface is expected to depend on a combination of factors including the type of oxygen species available, surface temperature, coadsorbates (with degree of surface coverage), as well as surface-level reconstruction. − In the present study, surface energetic stabilities and adsorption energies for various degrees of hydrogen- and oxygen-terminations have been examined theoretically for diamond (111)-1 × 1 and (111)-2 × 1 reconstructed surfaces. These results have been compared with the corresponding results for the (100)-2 × 1 surface, as presented earlier .…”