Expanding Thermal Plasma deposited a-Si:H thin films for surface passivation of c-Si wafers

Low thermal stability of hydrogenated amorphous silicon (a-Si:H) thin films limits their widespread use for surface passivation of c-Si wafers on the rear side of solar cells. We show that thermal stability of a-Si:H surface passivation is increased significantly by a hydrogen rich a-Si:H bulk which acts as an H reservoir for the a-Si:H/c-Si interface, when a spontaneous release of H from the bulk is induced by high temperature (450°C) annealing.