Comprehensive Research on Stability and Performance of a-Si:H and Alloys: Phase I Team Annual Technical Report, 31 May 1994 - 30 May 1995

This report covers the research done during the first phase of the subcontract. During this period, we concentrated on two areas: improving the voltage and stability of a-Si:H devices made using electron cyclotron resonance (ECR) deposition, and improving the properties of a-(Si,Ge):H films, also using ECR deposition. In the area of device research, we successfully solved the difficult problem ofcontrolling B diffusion at high temperatures from p into i layers in superstrate devices (where the p layer is the first layer deposited on a transparent conducting oxide). In our ECR technique research we systematically studied the deposition of a-(Si,Ge):H films using remote, low-pressure ECR techniques. We used two gases, H2 and He, as the primary plasma-region gases, and we found that theproperties of the film depend on which gas is used as the plasma gas. We find that the plasma potentials and ion energies are higher for He than for H2 plasma conditions. We believe that significant ion bombardment when He is used may account for the lower H content and the better electronic properties.