High rate growth of high-quality microcrystalline silicon films from plasma by interconnected multi-hollow cathode

We present guiding principles for obtaining high-quality microcrystalline silicon (μc-Si:H) films with regard to film-precursors and to their reactions on the film-growing surface, in which the contribution of short lifetime reactive species to film-growth determines the defect density of the resulting films except for temperature dependence. The importance of annihilation reactions of the short lifetime species with SiH₄ as well as that of their low generation rate is emphasized. The consideration of co-existing annihilation reactions of atomic hydrogen, important species for μc-Si:H formation, is also included. Based on the guiding principles, we propose a high rate deposition technique using high density very-high-frequency plasma produced with a newly designed interconnected multi-hollow cathode. Spatially-resolved optical emission spectroscopy indicated a radical separation effect introduced by the cathode. Device-grade μc-Si:H films with low defect densities (∼ 5 × 10¹⁵ cm^{- 3}) have been successfully prepared at deposition rates approaching 8 nm/s by means of this technique.