High Rate Deposition of DC Magnetron Sputtered a-Si for Photoreceptors

Abstract

High rate deposition of a-Si-layers is an important condition for an economical production of a-Si devices. We have obtained deposition rates of up to 30 μm/h by reactive DC magnetron sputtering from n-type and p-type doped monocrystalline silicon targets. The electrical properties of the films (dark conductivity, photoconductivity, activation energy) were examined as a function of the hydrogen partial pressure for the deposition rate of about 10 μm/h. The film structure is investigated by scanning electron microscope (surface and fracture) and hydrogen evolution method. The high rate deposited films show a homogeneous appearance exhibiting voids. The electrophotographic properties were examined for films on flat substrates. The charge acceptance for positive and negative charging is about 35V/pm with a low dark decay for films of the structure Al/SiO_x/a-Si/SiO_x. ESCA-measurements show an a-SiO_x-layer of 2nm on the top. The spectral sensivitity is examined.