Published online by Cambridge University Press: 15 February 2011
A transmission electron microscopy analysis has been made of the wet oxidation of polycrystalline silicon (poly–Si) films heavily doped with phosphorus in which the poly–Si–SiO2 interface has been given primary consideration. Using conventional and cross section transmission electron microscopy two distinct morphologies have been identified. Firstly, there is a region of enhanced oxidation at the poly–Si grain boundaries, with the concurrent formation of a new crystalline phase. Secondly, a significant roughening of the interface occurs, also associated with a crystalline phase. It is postulated that the formation of these features requires an inhomogenous distribution of the phosphorus dopant, which resulted from low temperature processing.