Characterization of crystalline quality of diamond films by Raman spectroscopy

We have measured Raman spectra of diamond films prepared by a hot-filament method and found that diamond layers on Si substrates are under compressive strain. The degree of the strain is found to increase with increasing nondiamond component in the diamond films. It is shown that Raman spectroscopy is a powerful method to estimate the crystalline quality, especially the strain in the diamond films.