Thin film transistors fabricated with poly-Si films crystallized by microwave annealing

Abstract

Solid phase crystallization has the advantages of low cost and excellent uniformity but the crystallization temperature is too high to use glass as a substrate. Using microwave annealing, we crystallized a-Si films at 550 degrees C within 3h, which is much shorter than the annealing time at 600 degrees C of furnace annealing. We fabricated TFTs with poly-Si films crystallized by microwave annealing at low temperature and obtained the characteristics to be slightly better than or at least comparable to the TFTs by furnace annealing in spite of smaller grain size. This may have been due to the improvement of surface roughness of poly-Si film. The poly-Si TFTs with PECVD a-Si film showed better characteristics than the TFTs with LPCVD a-Si film because of larger grain size and smoother Si/SiO2 interface.