Properties of bonded hydrogen in hydrogenated amorphous silicon and other hydrogenated amorphous silicon alloys

Abstract

This paper discusses bonding configurations of hydrogen atoms (H) in amorphous silicon and amorphous-silicon-based alloys. Recent experiments combined with theoretical calculations have identified two new aspects of bonded H that have not previously been addressed: (i) the formation of H bonds between H atoms on SiH groups and electronegative atoms or groups such as O atoms or NH groups; and (ii) an inherent metastability of H-bonded clusters as driven by the trapping of charged carriers. Both of these are shown to play important roles in (i) a photo-induced defect metastability such as the Staebler-Wronski effect, and (ii) hydrogen evolution from amorphous silicon nitrides. Finally, the concepts developed for a-Si:H alloys apply equally well to defect metastability at SiSiO 2 interfaces as in metal-oxide-semiconductor devices including insulated-gate field-effect transistors.