Si Thin Film Transistor Switch Matrix Address

3 a-Si Thin Film Transistor Switch Matrix Address 

The field effect mobility of carriers in the a-Si thin film is very low, owing to many dangling bonds on the surfaces of silicon grains which constitute the film. This problem is significantly lessened by hydro-genization of the a-Si film which decreases the density of dangling bonds from about 10 ° cm to about lO cm [57-58]. 

a metal (sch as Cr) layer is sputtered onto a glass substrate and etched to form a 

As explained above, the present TFT fabrication requires may complicated steps with many photolithographic processes. To simplify fabrication and increase process yields, a fabrication with fewer mask processes are being developed [73-83]. 

After development of the photoresist, the n a-Si and the i a-Si are etched away except for the semiconductor layers on the gate electrodes (d). An ITO layer is deposited and patterned to form drain, source and pixel electrodes (e). The n a-Si and a part of the i a-Si are etched by the reactive ion etching method (f). In this way, the two-mask-step TFTs is obtained. The SiN on the gate electrodes to be connected to peripheral driver ICs is etched away after the liquid crystal cell assembly process. 

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Figure 13. An image displayed with the a-Si thin film transistor switch matrix addressed liquid crystal display panel. (Courtesy of Hitachi Ltd.).

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