T. Sharda et al., STOICHIOMETRY OF THE DIAMOND SILICON INTERFACE AND ITS INFLUENCE ON THE SILICON CONTENT OF DIAMOND FILMS/, Journal of applied physics, 83(2), 1998, pp. 1120-1124
Thin films of diamond were grown by microwave plasma chemical vapor de
position at growth pressures of 10, 20, 40, and 60 Torr keeping the su
bstrate temperature constant at 975 degrees C. Increase in the growth
pressure reduced the size of the plasma ball resulting in an increase
in the microwave power density (MPD). The films were characterized by
scanning electron microscopy, micro-Raman, and photoluminescence (PL)
spectroscopy. A systematic variation was observed in surface morpholog
y and quality of the films. The intensity of the peak at 1.68 eV in th
e PL spectra of the films, which is assigned to Si impurities was also
observed to increase consistently with the MPD. The stoichiometry of
the diamond/silicon interface was studied by x-ray photoelectron spect
roscopy (XPS) and found to be a sensitive function of the MPD. XPS res
ults showed the formation of nonstoichiometric SiC along with other ca
rbon phases in the initial stages of the growth. A correlation was obs
erved between the composition of the interface and the intensity of th
e 1.68 eV peak. The above results are explained in terms of the increa
se in the impingement flux density of atomic hydrogen with the MPD. (C
) 1998 American Institute of Physics.