Structural characterization of silicon films deposited at low temperature by remote plasma enhanced chemical vapor deposition

Abstract

Silicon films were deposited at 430 °C by remote plasma chemical vapor deposition (RPECVD) with a gas mixture of Si 2H 6/ SiF 4/H 2. The silicon films deposited without and with SiF 4 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 SiF 4 exhibits more ruggedness. The silicon film deposited without SiF 4 is amorphous, whereas the silicon film deposited with SiF 4 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 SiF 4 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 SiF 4 during RPECVD is discussed.