Annealing effects in hydrogenated amorphous silicon layers

The annealing behaviour of defect structures in hydrogenated amorphous silicon, produced by hot wire chemical vapour deposition (HWCVD) has been studied by pulsed and conventional positron beam techniques and X-ray diffraction. Positron lifetime measurements show a dominant component corresponding to small vacancy clusters. Doppler Broadening measurements indicate that the size and concentration of defects varies with annealing temperatures up to 400 C. This behaviour is accompanied by a change from the amorphous to a partly crystalline structure, which can be observed by X-ray diffraction studies. (orig.)