Advanced Solid-Phase Crystallization of Amorphous Silicon on a Glass Substrate

Abstract

We report the crystallization of an amorphous silicon (a-Si) film by using advanced solid-phase crystallization (a-SPC). Solid-phase crystallization (SPC) is the most common method to obtain polycrystalline silicon (poly-Si). However, SPC requires a long annealing time to change from the a-Si phase to the poly-Si phase. The a-SPC method, which employs a high annealing temperature (above 700 degrees C) but a short annealing time, is investigated to overcome this disadvantage. After dehydrogenating at 450 degrees C for 2 hours, the a-Si films on Corning EAGLE glass substrates are annealed by rapid thermal processing (RTP). The UV-Vis spectrum reveals that the poly-Si appears for heat-treatment at 750 degrees C for 3 seconds. When the annealing time is increased until the critical point, at which the glass substrate bends, the crystalline fraction, as well as the quality of the poly-Si layer, improves. Raman spectroscopy confirms these results. The highest crystalline fraction is 96 % for an annealing time of 5 minutes.