DIAMOND POLYTYPES IN THE CHEMICAL-VAPOR-DEPOSITED DIAMOND FILMS

Micro-Raman spectroscopy and x-ray diffraction measurements have been used to identify the presence of hexagonal diamond polytypes in chemical vapor deposited diamond films, The presence of additional reflections, in addition to the normal cubic diamond reflections in the diffraction spectra and bands at 1306 and 1193 cm(-1) in the Raman spectra, are attributed to the presence of diamond 6H polytype. The presence of the 1324 cm(-1) band in addition to the main diamond peak in the expanded spectra is attributed to regions with hexagonal symmetry, thus supporting the presence of hexagonal diamond polytypes. The compressive strain in diamond layers on the Si substrate is believed to create regions of hexagonal symmetry and vice versa. (C) 1995 American Institute of Physics.