Structural evolution of amorphous silicon films during P-implantation

Abstract

The initiation and evolution of silicon hillocks induced by phosphorus implantation processes on the surface of amorphous LPCVD silicon films, for doses in the range 2/spl times/10/sup 14/ cm/sup -2/-8/spl times/10/sup 15/ cm/sup -2/ and 50 keV beam energy, were investigated by scanning electron microscopy. The hillock density increases as the implantation dose is raised up to 5/spl times/10/sup 15/ cm/sup -2/. Further increase of the dose to 8/spl times/10/sup 15/ cm/sup -2/ determines a steep decrease of the hillock density. The effects of both the concentration gradient of the as-implanted phosphorus atoms and the change of microstructure were considered in order to explain the hillock formation and evolution.