Dynamic Ni gettered by PSG from S-MIC poly-Si and its TFTs

A dynamic phosphor-silicate glass （PSG） gettering method is proposed in which the processes of the gettering of Ni by PSC and the crystallizing of α-Si into poly-Si by Ni take place simultaneously. The effects of PSC gettering process on the performances of solution-based metal induced crystallized （S-MIC） poly-Si materials and their thin film transistors （TFTs） are discussed. The crystallization rate is much reduced due to the fact that the Ni as a medium source of crystallization is extracted by the PSC during crystallization at the same time. The boundary between two neighbouring grains in S-MIC poly-Si with PSG looks blurrier than without PSG. Compared with the TFTs made from S-MIC poly-Si without PSC gettering, the TFTs made with PSC gettering has a reduced gate induced leakage current.     

The influence of SiNx substrate on crystallinity of μc-Si film used in thin film transistors

This paper found that the crystalline volume ratio （Xc） of μc-Si deposited on SiNx substrate is higher than that on 7059 glass. At the same silane concentration （SC） （for example, at SC=2%）, the Xc of μc-Si deposited on SiNx is more than 64%, but just 44% if deposited on Conning 7059. It considered that the ‘hills＇ on SiNx substrate would promote the crystalline growth of μc-Si thin film, which has been confirmed by atomic force microscope （AFM） observation. Comparing several thin film transistor （TFT） samples whose active-layer were deposited under various SC, this paper found that the appropriate SC for the μc-Si thin film used in TFT as active layer should be more than 2%, and Xc should be around 50%. Additionally, the stability comparison of μc-Si TFT and a-Si TFT is shown in this paper.