Simulation of gas phase reactions for microcrystalline silicon films fabricated by PECVD

Abstract

We present a numerical gas phase reaction model for hydrogenated microcrystalline silicon (μc-Si:H) films from SiH₄ and H₂ gas mixtures with plasma enhanced chemical vapor deposition (PECVD). Under the typical μc-Si:H deposition conditions, the concentrations of the species in the plasma are calculated and the effects of silane fraction (SF=[SiH₄]/[H₂+SiH₄]) are investigated. The results show that SiH₃ is the key precursor for μc-Si:H films growth, and other neutral radicals, such as Si₂H₅, Si₂H₄ and SiH₂, may play some roles in the film deposition. With the silane fraction increasing, the precursor concentration increases, but H atom concentration decreases rapidly, which results in the lower H/SiH₃ ratio.

Keywords

Film Growth / Plasma Enhance Chemical Vapor Deposition / Crystalline Fraction / Neutral Radical / Silane Fraction

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