DIAMOND STRUCTURE IN FILMS DEPOSITED AT RELATIVELY LOW SUBSTRATE-TEMPERATURE

Diamond films with strong features of diamond crystal have been prepared on Si substrates by DC plasma chemical vapor deposition (CVD), and the structural differences as a function of discharge current (Id) and substrate temperature (Ts) were investigated by scanning electron microscopy, reflection electron diffraction (RED) and Raman spectroscopy. When I d and decrease, the growth rate of the films as well as the size of the diamond grains decreases, and an amorphous second phase grows in relative amount. These results suggest that both the thermal and electron excitation of the reactive species on the substrate are important for the deposition of diamond, and that the increases in atomic hydrogen and electron impinging on the diamond surface are effective in the formation of diamond with a clear-cut crystal surface. It has been confirmed that the formation of diamond films is possible even at Ts around 400 °C when Id sufficiently large. © 1990, Elsevier Science Publishers B.V.. All rights reserved.