Towards a multiscale approach to the growth of silicon films by chemical vapor deposition

The morphological control of the surface of deposited films is one of the k ey points in the development of the microelectronics technology, in the fie ld of epitaxial as well as polycrystalline silicon growth. Nowadays, the gr owth rate profiles are almost optimized, while the surface morphology is st ill controlled almost empirically only. In this work, the growth of silicon films under CVD conditions is examined, in particular analyzing the tel-ra ce-step-growth mechanism. The growth process involves diffusive and kinetic steps, which obviously occur at different length scales. Our attention is focused on the processes occurring on the surface, ignoring the gas-phase r eactions, and evaluating the mass transport implications through a simplifi ed model. In this way, the micro- and macro-scale are investigated with two different approaches and afterwards they are linked together in a "toy rea ctor model". It becomes then possible to evidence the correlation between t he process conditions and the mechanism of surface formation. The condition s of cluster formation, preceding the polycrystalline growth and those of t errace instability, preceding the transition to amorphous film growth are b oth considered. The information on the industrially produced films and the available pictures of the surface obtained by atomic force microscope confi rm the theoretical findings. (C) 2000 Elsevier Science S.A. All rights rese rved.