Electrical characteristics of new LDD poly-Si TFT structure tolerant to process misalignment

A new lightly doped drain (LDD) poly-Si TFT structure having symmetrical el ectrical characteristics independent of the process induced misalignment is described in this paper. Based on the experimental results, we have establ ished that there is no difference between the hi-directional I-D-V-G charac teristics, and a low leakage current, comparable to a conventional LDD poly -Si TFT, has been maintained for this new poly-Si TFT's, The maximum ON/OFF current ratio of about 1 x 10(8) is obtained for the LDD length of 1.0 mu m. In addition, the kink effect in the output characteristics has been rema rkably improved in the new TFT's in comparison to the conventional non-LDD single- or dual-gate TFT's.