Low-temperature crystallization of doped a-Si:H alloys

Abstract

Crystallization of phosphorus‐doped a‐Si:H has been initiated at a substrate temperature below 200 °C, under the deposition conditions of a low flow rate of silane and in the presence of an external magnetic field. Along with the crystallization, the doping efficiency of the resulting Si:H films has been remarkably improved. Room‐temperature conductivity as high as 27 Ω⁻¹ cm⁻¹ has been achieved at a doping ratio of NPH₃/NSiH₄=5.6×10⁻³ for a specimen deposited at 30 C. Optical emission spectroscopy during the plasma deposition has revealed that a weak emission intensity of the SiH band with respect to hydrogen lines and the absence of emission from the doubly excited states of hydrogen molecules are necessary conditions for the crystallization of doped Si:H films.