Fast plasma deposition of carbon and silicon layers

By separating plasma production and plasma deposition and by taking advantage of the high specific ionizing power of thermal plasmas, very high deposition rates on large areas of amorphous C-H and Si-H are obtained. The layers have been analyzed by several methods, such as ellipsometry (band gap, absorption in the visible C-H, Si-H bonding types in the infrared), nuclear techniques (hydrogen depth profile), ESCA, and diffraction. The plasma is produced at high pressure (0.1-1 bar) in a cascaded arc in a carrier gas (argon). Downstream the feed gases (CH/sub 4/ and SiH/sub 4/) and additional gases (H/sub 2/) are admixed to the mainstream. Nearly complete dissociation and charge transfer from argon to Si and C takes place whereas the plasma is accelerated to sonic velocities at the high temperature (1 eV)