Nucleation and growth of Al-induced microcrystalline silicon in correlation with the microstructures of PECVD amorphous silicon

Using optical, transmission and scanning electron microscopy, the nucleation and growth of Aluminum-induced crystalline silicon was investigated in correlation with the microstructure of hydrogenated amorphous silicon (a-Si:H) deposited with plasma-enhanced chemical vapor deposition (PECVD) under different power densities. It was found that the microstructure of a-Si:H contains a considerable fraction of interstitial regions associated with (SiH2)n chains. As the deposition power density increases, the fraction of interstitial regions increases and the formation of a-Si:H changes from one-dimensional columnar forms to two-dimensional islands. It is proposed that the nucleation and growth of Al-induced crystalline silicon is closely related to the interstitial regions found in the microstructure of PECVD a-Si:H.