Channel Thickness Effect on High-Frequency Performance of Poly-Si Thin-Film Transistors

Abstract

In this letter, we present the high-frequency performances of polycrystalline silicon (poly-Si) thin-film transistors (TFTs) with a nominal gate length of 0.22 mu m. Owing to the short gate length and adoption of salicide process, cutoff frequency (f (T)) of 17 GHz and maximum oscillation frequency of similar to 21 GHz are obtained. The result suggests that the poly-Si TFT technology is applicable to RF integrated circuits up to 2 GHz. In addition, we also investigate the effects of channel thickness on the high-frequency characteristics of poly-Si TFTs. We find that the variation of f (T) with channel thickness is mainly due to the change in transconductance.