LASER REFLECTIVE INTERFEROMETRY FOR INSITU MONITORING OF DIAMOND FILM GROWTH BY CHEMICAL VAPOR-DEPOSITION

A simple laser reflective interferometer has been employed for in situ monitoring of diamond film growth in a hot-filament chemical vapor deposition reactor. This method uses a low power HeNe laser beam reflected at normal incident from the substrate. The high refractive index of the diamond film and the relatively high reflectivity of the Si substrate result in pronounced and easily detected interference oscillations in the reflected beam intensity. The oscillation period provides an accurate and immediate measure of the growth rate. In addition, the variations of the extrema of the oscillations provide an estimate of the quality and surface texture of the diamond films. Significant improvement in research productivity has been realized by using this technique.