Microwave Plasma Chemical Vapor Deposition of Diamond

Abstract

Early approaches to grow diamond from the vapor phase used thermal decomposition of carbon-containing gases such as CBr4 CI4, CO, or CH4, and were carried out at gas temperatures between 600°C and 1200°C. For these thermal low pressure chemical vapour deposition (CVD) processes, the gas temperatures did not differ much from the surface temperature of the diamond seeds used as substrates. Introduction of a hot zone in the CVD gas phase by means of activation elements such as hot graphite disks, or hot filaments led to substantially higher growth rates, revitalization of the field, and growing interest in vapor-deposited diamond by industrial corporations. Electron cyclotron resonance plasmas were introduced to diamond CVD because they seemed to offer an option to coat large substrate areas. Interaction of plasmas with substrate surfaces can be a serious problem for any plasma-based deposition process.