Byungseong Bae

A New Gate-Overlapped LDD Poly-Si Thin Film Transistors

We fabricate a new polycrystalline silicon thin film tansistor (poly-Si TFT), entitled a gate-overlapped lightly doped drain (GO-LDD)TFT, which may reduce the leakage current without sacrificing the ON current. The GO-LDD TFT may be fabricated easily by employing the buffer oxide without any additional LDD implantation. Experimental results show that the leakage current of the proposed TFTs is reduced by the magnitude of two orders, compar€d with tlat of conventional nonoffset TFT, while the ON current is not decreased. It is found that the high temperature process in GO-LDD TFT with LPCVD SirNl passivation layer make it difficult to conhol tle carrier concentration of the LDD region.