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.