Effect of substrates on morphological evolution of a film in the silicon CVD process: approach by charged cluster model

Abstract

Film morphology depends on the types of substrates used in the CVD process. This dependency has been studied based on the charged duster model in the silicon CVD process. There exists a strong correlation between microstructure evolution and the charge transfer rate (CTR) of substrate materials. Films tended to be porous on substrates with a high CTR and dense on substrates with low CTR. The microstructure evolution could be explained by the interaction of charged clusters with the substrate. On substrates with a high CTR, charged clusters lose their charge quickly prior to landing. The resultant neutral clusters undergo attraction-dominant random sticking (flocculation), leading to a porous structure. On substrates with a low CTR, charged clusters lose their charge slowly after landing and undergo repulsion-dominant selective sticking (deflocculation), leading to a dense film. (C) 2000 Elsevier Science B.V. All rights reserved.