Dual-gate MoS_2 transistors with sub-10 nm top-gate high-k dielectrics

摘要

High quality sub-10nm high-k dielectrics are deposited on top of MoS2 and evaluated using a dualgate field effect transistor configuration. Comparison between top-gate HfO2 and an Al2O3/HfO2 bilayer shows significant improvement in device performance due to the insertion of the thin Al2O3 layer. The results show that the Al2O3 buffer layer improves the interface quality by effectively reducing the net fixed positive oxide charge at the top-gate MoS2/high-k dielectric interface. Dualgate sweeping, where both the top-gate and the back-gate are swept simultaneously, provides significant insight into the role of these oxide charges and improves overall device performance. Dual-gate transistors encapsulated in an Al2O3 dielectric demonstrate a near-ideal subthreshold swing of similar to 60 mV/dec and a high field effect mobility of 100 cm(2)/V.s. Published by AIP Publishing.