Insitustudy of the growth of hydrogenated amorphous silicon by infrared ellipsometry

摘要

The early stage of the growth of plasma deposited amorphous silicon (ahyphen;Si:H) on glass substrates is investigated byinsituinfrared phase modulated ellipsometry in the siliconndash;hydrogen stretching mode region. Analysis of the spectra provides unprecedented sensitivity and quantitative information on the film evolution. In particular SiH, SiH2, and SiH3bonds are identified in 5ndash;20 Aring; thick samples. The bond densities of SiH and SiH2in thin films are estimated. After the interaction with the substrate,ahyphen;Si:H films grow beneath a hydrogen rich overlayer containing SiH2and SiH3bonds. At 250thinsp;deg;C the thickness of this overlayer is compatible with one monolayer. The hydrogenhyphen;passivated surface ofahyphen;Si:H is then weakly reactive.