Performance and reliability improvement for poly-Si TFTs using fluorinated silicate glass inter-layer-dielectric passivation

Abstract

Polycrystalline silicon thin-film transistors (poly-Si TFTs) with fluorinated silicate glass (FSG) inter-layer dielectric (ILD) passivation layer were proposed and demonstrated in this study. The presence of outdiffused fluorine atoms from FSG layer can eliminate Si dangling bonds at the grain boundaries near the drain side. The proposed short channel poly-Si TFTs with FSG ILD passivation have a slightly improved on-current, a obviously suppressed serious kink-effect, and a remarkably reduced off-leakage current than those with undoped SiO2 ILD passivation. Furthermore, the incorporation of fluorine atoms in poly-Si film can also form stronger Si-F bonds at drain side to enhance the immunity to hot carrier stress. Besides, the proposed TFTs structure is simple, low cost, and process compatible with present TFTs manufacturing technology.