Promotion of microcrystallization by argon in moderately hydrogen diluted silane plasma

Abstract

Using argon as a diluent of SiH_4, undoped hydrogenated microcrystalline silicon (μc-Si:H) films, having σ_D~10^-5 S cm^-1, were prepared at a very high deposition rate of 36 Å/min. Micrograins were identified with several well-defined crystallographic orientations. The effect of variation of Ar-dilution on the electrical and structural properties of Si:H films were studied systematically. Addition of H₂ to the Ar-diluted SiH₄ plasma improved the network structure by eliminating defects, introducing structural reorientation and grain growth, although, reducing the deposition rate. Accordingly, highly conducting (σ_D~10^-3S cm^-1) undoped μc-Si:H film was achieved utilizing energy released by de-excitation of metastable state of Ar (denoted as Ar*), in association with network modulation by atomic hydrogen in the plasma.