Morphology and mechanical behavior of diamond films fabricated by IH-MPCVD.

Morphology of diamond films has been controlled via intermediate frequency induction heated microwave plasma chemical vapor deposition (IH-MPCVD), which was transformed with various substrate temperatures ( T sub = 923-1123 K) and CH 4 /H 2 ratios ( η c = 0.5-2 vol%). The coupling effects of T sub and η c on the structure of diamond films have been studied. At η c = 0.5 vol%, the sp 3 /sp 2 ratio of diamond films reached 98% at 1073 K, surface roughness ( R ms ) increased from 50 to 85 nm with increasing T sub , the maximum hardness ( H a ) reached 84 GPa at 973 K, and the maximum Young's modulus ( E ) reached 642 GPa at 1023 K. The residual stress ( σ ) was calculated as a function of T sub and η c . The quality factor ( Q ), combining microstructure and mechanical behavior, has been creatively defined to evaluate the quality of diamond films.