Study on crystallization of amorphous silicon using CeO 2 seed layer patterned on the plastic substrate

Abstract

Many researchers are working these days on crystallization of amorphous silicon (a-Si) for application in thin film transistor-liquid crystal display (TFT-LCD) on the plastic substrate. In this paper, we have presented our work on crystallization of amorphous silicon film using XeCl excimer laser annealing on the polyethersulfone (PES) substrate. We have also reported here the consequences of our attempt to pattern CeO 2 seed layer as dot and line between Si film and the PES substrate. Previous researchers in this field have shown that laser of high-energy density is required to crystallize a-Si films without using seed layer. But, we have successfully obtained the crystallization condition using laser of low-energy density using a seed layer of CeO 2. This paper reports the achievement in details. Also, we have drawn a comparison of a-Si crystallization between the case with and without seed layer. Generally, a-Si films are deposited at low temperature on plastic substrates. In our experiment, CeO 2 film was grown by RF sputtering using plasma ON/OFF method at the room temperature. Amorphous silicon was deposited by inductively coupled plasma chemical vapor deposition (ICP-CVD) at the room temperature. Then, active layer was crystallized by XeCl excimer laser irradiation. We determined the crystallinity through Fourier transformation Raman spectroscopy (FT-Raman spectroscopy).