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

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 microstructu re evolution and the charge transfer rate (CTR) of substrate materials. Fil ms tended to be porous on substrates with a high CTR and dense on substrate s with low CTR. The microstructure evolution could be explained by the inte raction of charged clusters with the substrate. On substrates with a high C TR, charged clusters lose their charge quickly prior to landing. The result ant neutral clusters undergo attraction-dominant random sticking (flocculat ion), leading to a porous structure. On substrates with a low CTR, charged clusters lose their charge slowly after landing and undergo repulsion-domin ant selective sticking (deflocculation), leading to a dense film. (C) 2000 Elsevier Science B.V. All rights reserved.