A self-aligned offset polysilicon thin-film transistor using photoresist reflow

A simple fabrication method for a self-aligned offset structure, which uses photoresist reflow, is developed to reduce the leakage current of polysilicon thin-film transistors (poly-Si TFT's), The reflow of photoresist can be controlled by varying photoresist thickness and reflow temperature. It is found that the reflow length increases in proportion to the photoresist thickness, and increases with increasing reflow temperature at less than 200 degrees C for the AZ5214A photoresist, Poly-Si TFT's are successfully demonstrated with offset lengths of 0.4 and 0.6 mu m, which show apparent reduction of the leakage current.