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.