Submicron ambipolar nanocrystalline-silicon TFTs with high-K gate dielectrics

Thin-film transistors (TFTs) that use hydrogenated nanocrystalline-silicon (nc-Si) as the channel material are favorable for use in neuromorphic circuits [1] as well as in flat-panel displays. Nanocrystalline-Si can be deposited over large areas at low temperatures, thus enabling three-dimensional integration with CMOS structures. Recently, nc-Si TFTs that exhibit high channel mobility and provide stable operation under voltage bias stress have been fabricated [2]. In this work, the subthreshold swing, electron and hole threshold voltages (V_T), and field-effect mobilities are considerably improved by using high-K dielectrics instead of SiO₂. These gains will translate to circuits with lower operating voltages at the same performance.