Published online by Cambridge University Press: 21 February 2011
In order to control the quality and properties of hydrogenated amor-phous silicon (a–Si:H) semiconductors produced by discharge deposition, we would like to control the gas species produced in the discharge and to understand how these deposit and influence the film properties. One would like to separately consider the gas processes that yield the mix of species arriving at the surface, and then the surface processes. I will somewhat follow that separation here, but it appears that many of the species found in the gas may, in fact, be released from the surface. Thus, the gas species appear to result from gas and surface reactions, and a sequential separation is actually not possible. Similarly, the study of the surface deposition process requires forming various radical species as well as an a–Si:H surface, which inevitably will involve the gas processes. Thus we really have coupled problems.