A 24 CM DIAGONAL TFT-LCD FABRICATED USING A SIMPLIFIED, 4-PHOTOLITHOGRAPHIC MASK PROCESS

Amorphous silicon thin film transistors (a-Si TFTs) with a channel-etc hed structure were fabricated. The key technologies to realize these s imple-process TFTs were 1) fabricating data lines and pixel electrodes of indium tin oxide (ITO); 2) carrying out tapered dry etching of plu ral layers of the a-Si and gate insulator silicon nitride; and 3) form ing silicide layer to reduce the contact resistance between the phosph orous-doped a-Si and ITO. Excellent image quality, with a high contras t ratio of more than 100: 1, was obtained for video graphic array (VGA ) mode TFT-LCDs using a dot inversion driving method. Furthermore, the transmission distribution was uniform with less than a 4.5% deviation on the whole display area although the ITO data line resistances were as large as 120 k Ohm per line.