Effect of Channel-Width Widening on a Poly-Si Thin-Film Transistor Structure in the Linear Region

Abstract—This is the first paper to discuss the ON-state drain–current of a special thin-film transistor structure with a wide channel width and a narrow source/drain width in the linear region. The experimental results indicate that when the channel width is wider than the source/drain width, the side-channel current effect is generated. This effect increases the ON-state drain–current due to the additional current-flow paths exist-ing in the side-channel regions and low channel resistance. As the side-channel width increases, the ON-state drain–current ini-tially increases and then gradually becomes independent of the side-channel width when the side-channel width is larger than the effective side-channel width, which depends on the channel width and is largely independent of the source/drain width. This paper also demonstrates that the ON-state drain–current gain is directly proportional to the channel length and the ratio of the channel length to the source/drain width and dependent on the side-channel width. Index Terms—Drain–current, poly-Si thin-film transistor (TFT), source/drain width, wide channel width. I