Diamond growth on WC-Co substrates by hot filament chemical vapor deposition: Effect of filament–substrate separation

Abstract

Polycrystalline diamond films have been grown by hot filament (HF) chemical vapor deposition on WC-Co bar substrates using different CH 4/H 2 source gas mixing ratios and two different total gas pressures. Each substrate was mounted so as to span a range of HF-substrate separations, d f , (and thus substrate temperatures) and therefore samples a spread of incident gas phase chemistry and compositions. Spatially resolved scanning electron microscopy and Raman analysis of the deposited material provides a detailed picture of the evolution of film morphology, growth rate, sp 3 / sp 2 content and stress with d f in each deposited sample, and of how these properties vary with process conditions. The experimental study is complemented by two-dimensional model calculations of the HF-activated gas phase chemistry and composition, which succeeds in reproducing the measured growth rates well.