PARTICLE FORMATION IN SIOX FILM DEPOSITION BY LOW-FREQUENCY PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

Dust particle formation dynamics in the process of SiOx film depositio n from a SiH4 and N2O gas mixture by a low frequency plasma enhanced c hemical vapor deposition have been investigated using scanning electro n microscopy and laser light scattering. The deposited films are confi rmed to be SiOx from the measurements of Auger electron spectroscopy, x-ray photoelectron spectroscopy, and Fourier transform infrared spect roscopy. It is observed by scanning electron microscopy that particles are deposited on Si substrate at the plasma power frequency f=5 kHz a nd above both with and without substrate heating (400 degrees C), whil e no particle is deposited below f=1 kHz. Moreover, the laser light sc attering indicates that particles are generated at the plasma power fr equency of f=3 kHz and above in the gas phase, and that they are not g enerated in the gas phase at below f=3 kHz. Properties (the refractive index, resistivity, and Vickers hardness) of the films with particles are inferior to those of the films without particles. This article ha s revealed experimentally the effect of plasma power frequency on SiOx particle formation and makes a contribution to the explication of the particle formation mechanism. We suggest that high-quality film depos ition with the low frequency plasma enhanced chemical vapor deposition method is attained at f=1 kHz or less without substrate heating. (C) 1998 American Institute of Physics.