In situ X-ray diffraction studies of aluminium-induced crystallization of hydrogenated amorphous silicon

Thin intrinsic hydrogenated amorphous silicon (α-Si:H) films (5000 Å thickness) were deposited on (111)-oriented n-type silicon substrates by plasma-enhanced chemical vapor deposition. A 4000 Å thick Al film was then deposited on the α-Si:H film by vacuum evaporation. In situ annealing of these films was carried out in an evacuated temperature-controlled (Model TTK) camera of an X-ray diffractometer at a glancing angle of 5° using a thin-film optics attachment. The crystallization behavior of aluminium-capped α-Si:H was monitored using the 111 silicon peak as a function of annealing temperature between 273–523 K. The results show that aluminium-induced crystallization of α-Si:H initiates at a temperature between 413 and 423 K. The crystallization rate increases with increasing temperature, and saturates for an anneal of 30 min at a temperature of 523 K.