Effects of phosphorus on stress of multi-stacked polysilicon film and single crystalline silicon

In multi-stacked polysilicon films, the stress was examined in terms of dop ant distribution and the polysilicon/polysilicon interface at which phospho rus and oxygen atoms were piled up. The phosphorus dopant introduced the co mpressive stress in the films. The thin oxidized layer formed at the interf ace was an important factor governing the stress gradient in the multi-stac ked film. This interface effect could be minimized using symmetrical stacki ng of polysilicon films and resulted in a low stress gradient of -0.15 MPa mu m(-1) for a 5.3 mu m thick polysilicon layer. In single crystalline sili con, the phosphorus dopant induced the tensile stress. The lattice dilation coefficient beta of 4.5 x 10(-24) cm(3) for phosphorus was measured using a high-resolution x-ray rocking curve. A stress model was introduced on the basis of the lattice dilation theory to calculate the stress and stress gr adient induced by the dopant.