Polycrystalline Si (poly-Si) thin-film solar cells on glass feature the potential to reach high single-junction efficiencies at low costs. However, the preparation is challenging because the process temperatures are limited by the glass to about 600 degrees C. There are several methods to prepare poly-Si films on glass. So far, the best poly-Si thin-film solar cells on glass have been prepared by solid phase crystallization (SPC) of amorphous Si (a-Si). In this paper, we give an overview on the formation of poly-Si films by both SPC and the aluminum-induced layer exchange (ALILE) process (which is based on aluminum-induced crystallization (AIC) of a-Si). Due to the fact that the utilization of ZnO:Al-coated glass is an attractive option for future poly-Si thin-film solar cells, we discuss the influence of an additional ZnO:Al layer on the formation of poly-Si films. Such an additional ZnO:Al layer leads to enhanced nucleation. Thus, the time necessary to form the poly-Si film (process time) and the resulting grain size of the poly-Si film are reduced. (C) 2009 Elsevier B.V. All rights reserved.