In this paper, we report on the deposition of amorphous silicon (a-Si:H) films at ultra-high growth rate (11-60 nm/s) by means of the expanding thermal plasma technique, followed by solid-phase crystallization (SPC). Large-grain (similar to 1.5 mu m) polycrystalline silicon was obtained after SPC of high growth rate (similar to 25 nm/s) deposited a-Si:H films. The obtained results are discussed by taking into account the impact of the a-Si:H microstructure parameter R* as well as of its morphology, on the final grain size development. (C)@en

In this paper the effect of the microstructure of remote plasma-deposited amorphous silicon films on the grain size development in polycrystalline silicon upon solid-phase crystallization is reported. The hydrogenated amorphous silicon films are deposited at different microstructure parameter values R* (which represents the distribution of SiH(x) bonds in amorphous silicon), at constant hydrogen content. Amorphous silicon films undergo a phase transformation during solid-phase crystallization and the process results in fully (poly-)crystallized films. An increase in amorphous film structural disorder (i.e., an increase in R*), leads to the development of larger grain sizes (in the range of 700-1100 nm). When the microstructure parameter is reduced, the grain size ranges between 100 and 450 nm. These results point to the microstructure parameter having a key role in controlling the grain size of the polycrystalline silicon films and thus the performance of polycrystalline silicon solar cells.@en