A Novel Design of Quasi-Lightly Doped Drain Poly-Si Thin-Film Transistors for Suppression of Kink and Gate-Induced Drain Leakage Current

An ultrathin channel of poly-Si thin-film transistors with a quasi-lightly doped drain (Q-LDD) structure, which reduces the kink current considerably, have been proposed and fabricated. The doping concentration on the poly-Si channel was adjusted by the different thickness between source-drain and LDD region. The proposed Q-LDD shows advantages of using a thin channel and a thin-gate insulator, comparing with the conventional fabrication process of LDD using a thick oxide side walls. The gate-induced drain leakage currents were successfully suppressed without sacrifice of the ON-current and threshold voltage. Moreover, the kink effect also reduced.