Impurity dependence of film-edge-induced dislocations in silicon

An experimental study is designed to reveal the generation of dislocations resulted from the interaction of discontinuous low-pressure chemical-vapor-deposited (LPCVD) nitride/thermal pad oxide window edge and atomic misfit stress. The results show that atomic misfit has a very strong effect on the dislocation generation along the film edges. Boron exhibits a misfit factor of (−)0.254, while arsenic has almost zero misfit factor in silicon. Hence the ratio of LPCVD nitride/thermal pad oxide thickness to generate film edge dislocations for boron-doped silicon is at least three times lower compared with arsenic doped silicon. The increase of boron concentration reduces the thickness ratio of LPCVD nitride/pad oxide required to the generation of dislocations. This study shows that film-edge-induced dislocation is strongly dependent on impurity species and concentration.