Low Temperature (150–250°C) Deposition of n+ and p+ Microcrystalline Silicon for VLSI Device Contacts

Abstract

ABSTRACTThe rf glow discharge decomposition of dilute mixtures (∼1%) of SiH4 in H2, with suitable doping agents such as PH3 or B2 H6 added, produces n+ and p+ microcrystalline (μc) silicon films with resistivities (ρ) in the 10−1 Ω.cm range at exceedingly low substrate temperatures Ts (150–250°C). The μc-Si films consist of two phases with crystalline clusters embedded in an amorphous matrix. The films are stable when temperature-cycled in the 30–400°C range and the resistivity decreases when annealed above the original deposition temperature. A model of microcrystalline film growth involving the reactions between the gas phase radicals and the growing film surface is proposed.