The Effect of Low Pressure on the Structure of LPCVD Polycrystalline Silicon Films

Abstract

Structure and crystal growth of undoped silicon films prepared by low pressure chemical vapor deposition (LPCVD) have been investigated by x‐ray diffraction, and transmission and scanning electron microscopy. We show that for films deposited in silane partial‐pressure range and temperature range , the pressure is a determining factor for crystallite size, texture, and surface roughness. At a fixed temperature, the crystallite size decreases when the pressure increases. At very low pressures the films have a random orientation. At intermediate pressures the films are characterized by a <100> dominant texture and at high pressure, by a strong <110> preferred orientation. The surface roughness is closely related to the preferred orientation.