Aluminum-induced crystallization of amorphous silicon: Influence of temperature profiles

Annealing of amorphous silicon/aluminum layer stacks below the eutectic temperature leads to a layer exchange and concurrent crystallization of silicon. The resulting polycrystalline silicon layers are of great interest for large area thin film devices. This paper reports about the influence of annealing temperature profiles on the layer exchange process. It is shown that temperature profiles have pronounced influence on the nucleation process. The obtained results are helpful for a better understanding of the physics of the layer exchange process and for an improvement of the layer exchange process by allowing for a reduction of the process time with a simultaneous increase in grain size. It is shown in particular that the characteristic suppression of nucleation is caused by Si-depletion around the growing Si-grains.