Hydrogen Implantation into Silicon. Infra-Red Absorption Spectra and Electrical Properties

Hydrogen and deuterium implantations into crystalline silicon (c-Si) are carried out at room temperature. Infra-red spectra and electrical property studies are performed on these samples before and following annealing. Analysis of the vibrational spectra shows at least two types of bonding for hydrogen in c-Si, which are identified as SiH1, (SiH2)2 units. A strong evidence of SiH2 group formation is obtained for the relatively low hydrogen concentration in c-Si in comparison with a-Si:H. On the basis of the kinetics of formation and annealing of SiH vibrations and scanning micrograph data it is concluded that the microvoids with reconstructed inner surfaces, and hydrogen passivating dangling bonds, are effectively produced due to divacancy type defect agglomeration followed by hydrogen trapping. The electrical properties of c-Si:H are discussed also.