Polycrystalline Si films formed by Al-induced crystallization (AIC) with and without Al oxides at Al/a-Si interface

Al-induced crystallization (AIC) without an Al oxide at the Al/a-Si interface (glass/Al/a-Si) was investigated in comparison with the case of an Al oxide (glass/Al/Al oxide/a-Si). The Si crystallization of Al/a-Si during AIC was much faster than that of Al/Al oxide/a-Si. The annealing of glass/Al/a-Si led to poly-Si films with small Si grains compared to that of glass/Al/Al oxide/a-Si. It is difficult to observe the influence of the crystallization temperatures (400–500°C) on the crystallization of glass/Al/a-Si. With annealing of glass/Al/a-Si at 300°C, the crystallization of a-Si occurred not only in the original Al layer but also in the original a-Si layer. With lowering crystallization temperature of glass/Al/Al oxide/a-Si, it is observed that poly-Si films become oriented preferentially in the (1 0 0) direction normal to the surface and had larger grains. These preferentially (1 0 0) oriented Si thin films can act as good seed layers for the growth of the active layers by liquid phase epitaxy.