Consideration of a Local Aluminum-Induced Crystallization Process Guided along the μ-Holes Fabricated with fs Laser Pulses

摘要

A polycrystalline silicon (poly-Si) film is produced by the aluminum-induced crystallization (AIC) process guided along the μm-sized laser hole and characterized for application to a seeding layer of poly-Si solar cells. We investigated the crystallization of amorphous silicon (a-Si) films using the AIC process with a structure of glass/Al/SiO2/a-Si in which the silicon oxide (SiO2) layer has holes with 1 ~ 2 μm in diameter so that the AIC process occurred only through the hole. The purpose of our experiment is to see the poly-Si grain growth, if possible, from a single poly-Si seed in the AIC process. For the experiment, the microhole array of about 1 ~ 2 μm in diameter is prepared in the SiO2 layer of the structure using femtosecond laser pulses and the AIC process is carried out with the conventional heat treatment procedure. As results, it is observed that the crystallization of a-Si occurred only in the area under the microhole and the grain of poly-Si grew to the size of over 3 μm. Furthermore, it was shown that the grain grew with one dominant crystal orientation.