Silicon wafer with superimposed polycrystalline silicon films on one main surface and its fabrication method

摘要

A silicon wafer has a polycrystalline silicon film formed on one main surface. The polycrystalline silicon film has a multilayer structure composed of X layers (X is an integer equal to or greater than two) containing <220> oriented components in different proportions. The proportion of the <220> oriented component in the first polycrystalline silicon layer in contact with the silicon wafer is larger than the respective proportions of the <220> oriented components in the second to X-th polycrystalline silicon layers superposed on the first polycrystalline silicon layer. It becomes possible to provide a silicon wafer whose polycrystalline silicon film possesses high gettering capability and in which stress acting on the silicon wafer is decreased.