Characterization of Synthetic Diamond Thin Films.

High‐pressure, microwave plasma‐assisted chemical vapor deposition is employed to deposit diamond thin films, using a gas mixture of methane and hydrogen on single‐crystal silicon substrates. The deposition rate is approximately 1 micron/h. As‐deposited diamond thin films on a silicon substrate and free‐standing diamond thin films are analyzed by scanning electron microscopy, Raman spectroscopy, and x‐ray diffraction. Thermal stability of free‐standing diamond thin films is studied in oxygen and argon ambient, separately, using thermogravimetric analysis. It is found that these films maintain integrity in oxygen up to 676°C.