VERY-LOW-TEMPERATURE PREPARATION OF POLY-SI FILMS BY PLASMA CHEMICAL VAPOR-DEPOSITION USING SIF4/SIH4/H2 GASES

Polycrystalline-Si (poly-Si) films have been prepared on glass substrates (Corning 7059) at a very low temperature (300-degrees-C) by conventional plasma chemical vapor deposition (plasma CVD) using SiF4/SiH4/H-2 gases. The crystallinity was characterized by X-ray diffraction, reflection high-energy electron diffraction (RHEED), transmission electron microscopy (TEM) and Raman spectroscopy measurements. The effect of the SiH4 flow rate on crystallization proved to be large. The films indicated a strong <110>-preferred orientation. The crystalline fraction was estimated to be more than 80%. The average and maximum grain sizes were estimated to be 60 nm and 130 nm, respectively.