Structural and Electrical Properties of Polysilicon Films Prepared by AIC Process for a Polycrystalline Silicon Solar Cell Seed Layer

Polycrystalline silicon (pc-Si) films are produced by aluminum-induced crystallization (AIC) process for a polycrystalline silicon solar cell seed layer, and the structural and electrical properties of the films are analyzed. The used structure is glass/Al/ Al2O3/a-Si, and the thickness of Al2O3 layer was varied from 2 nm to 20 nm to investigate the influence of the Al2O3 layer thickness on the formation of the polycrystalline silicon. The annealing temperature and annealing time were fixed to 400∘C and 5 hours, respectively, for the AIC process conditions. As a result, it is observed that the average grain size of the pc-Si films is rapidly smaller with increasing the thickness of Al2O3 layer, whereas the film quality, as defects and Hall mobility, was gradually degraded with only small difference. We obtained the maximum average grain size of 15 μm for the pc-Si film with the thickness of Al2O3 layer of 4 nm. The best resistivity and the Hall mobility was 6.1×10−2 Ω⋅cm and 90.91 cm2/Vs, respectively, in the case of 8 nm thick Al oxide layer.