(Received August 30, 1990; accepted for publication October 20, 1990)
This paper theoretically explores the SiNx CVD film growth mechanism by means of the ab initio molecular orbital method. In a chemical vapor deposition (CVD) reactor, an SiH4 and NH3 gas mixture produces silylenes (X-Si-Y: X and Y are substituents). The insertion of silylene into a surface Si-H or N-H bond is the important part of the CVD film growth mechanism. Following the insertion, H2-elimination reaction occurs from the surface. The film growth mechanism explains Si-H and N-H bonds remaining ih an SiNx film and the deviation from the stoichiometry. Based on the mechanism, it is suggested that a new source gas, SiNH5, instead of SiH4 deposits a stoichiometric SiNx film, and that a transition layer exists between the native oxide and the bulk SiNx film.