PREPARATION AND PROPERTIES OF ION BEAM DEPOSITED a-SiH_x

Abstract
Ion beam deposition (IBD) has been used to prepare a-SiH_x thin films over a range of deposition conditions. Concentration of hydrogen in the ion beam is found to be a major factor in determining the properties of these materials. Increasing the hydrogen concentration of the ion beam from 0 to 75% produces a monotonic decrease in room temperature dark conductivity from 10^-3 to 10^-10 (Ωcm)^-1. This is accompanied by an increase in the optical band gap from 1.2 to 1.8 eV and a decrease in the esr spin density to < 10¹⁷cm^-3. Monohydride SiH bonding predominates in the ir spectra with no evidence for polysilane coordination. Densities are greater than 2.2 g/cm³ for all films made in this study suggesting an absence of voids. Phase contrast TEM gives no indication of columnar morphology.