Fabrication and characterization of T-gate polysilicon thin-film transistors with lightly-doped drain

Abstract

We report detailed fabrication and characterization of poly-Si thin-film transistors (TFTs) with T-shaped gate (T-gate) and lightly-doped drain (LDD) structures. The formation of the LDD underneath the wings of a T-gate primarily relies on the shadowing of implanted dopants during the implantation of source and drain. Therefore, the fabrication of LDD structures in our proposed T-gate poly-Si TFTs can save a number of process steps as compared to conventional poly-Si TFTs with LDD structures. Our fabricated T-gated poly-Si TFTs with LDD structures not only exhibit suppressed off-state leakage current but also show a significant improvement in on-state current as compared to that of conventional poly-Si TFTs with the same top-gate dimension.

Monolithically Integrated Polysilicon/Oxide-Semiconductor Hybrid Thin-Film Transistors for Advanced Sensing

“…6 that the threshold voltage (VTH) decreases while subthreshold swing (SS) tends to improve with decreasing L, which are attributable to short-channel and drain-inducedgrain-barrier-lowering (DIGBL) effects [19] [20]. Previous reports [21] [22] have pointed out that the DIGBL effect tends to reduce the effective defect density in the poly-Si channel as L is shortened, and thus improves SS at short channels. Another important and impactful finding of the notes is the influence of the S/D contacts.…”