A novel polysilicon thin-film transistor with a p-n-p structured gate electrode

We propose and fabricate a novel polycrystalline silicon thin-film transistor (poly-Si TFT) which exhibits the properties of an offset gated structure in the OFF state, while acting as a nonoffset structure in the ON state. The fabrication process is compatible with the conventional nonoffset poly-Si TFT´s process and does not require any additional mask. Experimental results show that the leakage current of the new device is two orders of magnitude lower than that of the nonoffset gated device, while the ON current of the new device is almost identical to the nonoffset gated device. It is observed that the ON/OFF current ratio of the proposed poly-Si TFT is improved remarkably.