INTERACTION BETWEEN GROWING AMORPHOUS-SILICON AND GLASS SUBSTRATE EVIDENCED BY INSITU INFRARED ELLIPSOMETRY

An in situ study of the formation of glass/hydrogenated amorphous silicon (a-Si:H) and glass/a-SiC:H interfaces by infrared (IR) phase modulated ellipsometry (PME) is presented. The high sensitivity of this new expermental technique is emphasized. In particular as compared to UV-visible ellipsometry IRPME allows a direct identification of the chemical species incorporated in a film. The presence of a chemical interaction during the formation of the Corning glass/a-Si:H (or a-SiC:H) interface is directly revealed by the vibration (near 1480 cm-1) of BO groups, coming from the substrate, incorporated into growing a-Si:H (or a-SiC:H). The boron remains incorporated into an interface layer buried at the interface. The mechanisms of this boron incorporation in the amorphous films during the early stage of the growth are discussed. Some possible technological consequences of these behaviors are mentioned.