STRUCTURAL CHARACTERIZATION OF SILICON FILMS DEPOSITED AT LOW-TEMPERATURE BY REMOTE PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

Silicon films were deposited at 430 degrees C by remote plasma chemical vapor deposition (RPECVD) with a gas mixture of Si2H6/SiF4/H-2. The silicon films deposited without and with SiF4 were characterized using atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Both silicon films have the same rugged surface morphology, but, the silicon film deposited with SiF4 exhibits more ruggedness. The silicon film deposited without SiF4 is amorphous, whereas the silicon film deposited with SiF4 is polycrystalline with very small needle-like grains which are perpendicular to the substrate and uniformly distributed in the thickness of the film. The silicon film deposited with SiF4 was found to have a preferred orientation along the growth direction with the [110] of the film parallel to the [111] of the substrate. The effect of SiF4 during RPECVD is discussed.