PREPARATION OF 3-DIMENSIONALLY ORIENTED POLYCRYSTALLINE SI FILM

The crystal structure and morphology of polycrystalline Si films depos ited using a plasma-enhanced chemical vapor deposition method, have be en investigated by x-ray diffraction and atomic force microscopy. When the [110]-oriented films were prepared at 690 degrees C with a hydrog en dilution ratio H-2/SiH4=3 and rf power of 20 W, it was found that t he grains with almost the same size are uniformly distributed within t he film, and their shapes in a top view become rectangular. The longer sides of rectangles stand in line in the direction of gas flow (the p lasma also spreads in this direction), indicating that the gas-flow di rection and the plasma assist the growths of essentially three-dimensi onally oriented grains. (C) 1996 American Institute of Physics.