A study of polycrystalline silicon thin films as a seed layer in liquid phase epitaxy using aluminum-induced crystallization

In this paper, the making of polycrystalline silicon thin films as a seed layer for thicker polycrystalline thin film Si solar cells was investigated. The seed layer was crystallized using Aluminum-induced crystallization (AIC) in various process conditions in order to determine the optimized process parameters of AIC. The layer exchange process and the a-Si crystallization during AIC (annealing at 500 degreesC, 1 h) were observed. The crystallized and continuous poly-Si thin films were formed with the same thickness as Al layers. However, as the thickness of Al decreased, a continuous film became thinner and more protrusions were observed at film surface. The grain size of crystallized Si thin films ranged from 2000 Angstrom to more than 1 mum. The hole concentration, Hall mobility, and resistivity were 3.79-7.00 x 10(18) cm(-1), 19.9-36.5 cm(2)/Vs, and 0.037-0.045 Omegacm, respectively. These results indicate that the fabrication of poly-Si thin films using AIC is an industrially relevant techniques because of low-temperature process and short processing time. The crystallized film with grains more than 2000 A will be a good candidate of seed layers for liquid phase epitaxy. (C) 2001 Published by Elsevier Science B.V.