Characteristics of offset-structure polycrystalline-siliconthin-film transistors

In order to reduce anomalous leakage current from n-channel polycrystalline-silicon thin-film transistors (poly-Si TFTs), an offset structure that has an n^- region between channel and n⁺ source-drain electrodes has been proposed. Drain-current measurements of the poly-Si TFT prove that the offset structure is effective in reducing the anomalous leakage current, and that the optimization of the offset length and the doping concentration in the offset region enlarge the ON/OFF current ratio. Implantation of 5×10¹³ cm^-2 phosphorus ions in the offset region makes the ON/OFF current ratio more than one order of magnitude larger than that of conventional structure TFTs