Preparation of three-dimensionally oriented polycrystalline Si film

Abstract

The crystal structure and morphology of polycrystalline Si films deposited using a plasma-enhanced chemical vapor deposition method, have been investigated by x-ray diffraction and atomic force microscopy. When the 〈110〉-oriented films were prepared at 690 °C with a hydrogen dilution ratio H2/SiH4=3 and rf power of 20 W, it was found that the grains with almost the same size are uniformly distributed within the 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 plasma also spreads in this direction), indicating that the gas-flow direction and the plasma assist the growths of essentially three-dimensionally oriented grains.