We propose the new poly-Si TFT structure which reduces the leakage current effectively employing highly resistive a-Si region in the channel. This new device has selectively crystallized active layer, where both edges of channel region adjacent to source and drain are not crystallized and remain a-Si. In the proposed device, the amorphous silicon region behaves like an offset to reduce the leakage current and also acts as the conduction channel of carriers under the ON state, so that the ON-current can be maintained. The experimental results show that the ON/OFF current ratio of proposed device is 2.71×106 while that of conventional one is 2.67×105. In the fabrication of the proposed device, there are not any additional photomasking steps and mis-align problem.