Abruptness of a-Si:H∕c-Si interface revealed by carrier lifetime measurements

Intrinsic hydrogenated amorphous silicon films can yield outstanding electronic surface passivation of crystalline silicon wafers. In this letter the authors confirm that this is strongly determined by the abruptness of the interface. For completely amorphous films the passivation quality improves by annealing at temperatures up to 260°C, most likely by film relaxation. This is different when an epitaxial layer has been grown at the interface during film deposition. Annealing is in such a case detrimental for the passivation. Consequently, the authors argue that annealing followed by carrier lifetime measurements allows determining whether the interface is abrupt.