High-performance a-Si:H thin-film transistor using lightly doped channel

The fabrication of amorphous silicon thin-film transistors (TFTs) using a lightly phosphorus-doped channel is discussed. The transistors achieve an on-off current ratio exceeding six orders of magnitude and a field effect mobility of 0.4 cm/sup 2//V-s. These characteristics are found to be much better than those using an undoped channel with the same device structure. It is found that the incorporation of phosphorus in the channel can compensate the interface states and improve the transconductance of the TFT. It is shown that the fabrication of a depletion-mode TFT is fully compatible with the conventional enhancement-mode TFT process.<
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