Top-Gated MoS₂ Negative-Capacitance Transistors Fabricated by an Integral-Transfer of Pulsed Laser Deposited HfZrO₂ on Mica.

Top-gated (TG) molybdenum disulfide (MoS2) field-effect transistors (FETs) suffer from surface damage, unintentional doping, and other defects introduced to the MoS2 channel during the direct deposition of the gate dielectric. In addition, the delicate MoS2 cannot withstand high-temperature processing or annealing. To overcome these obstacles, a novel path to prepare TG MoS2 negative-capacitance (NC) FETs is proposed in this study. A ferroelectric HfZrO2 (HZO) is first deposited on the mica flake by pulsed laser deposition (PLD) and then annealed by rapid thermal processing. Subsequently, the HZO/mica stack is integrally transferred onto the MoS2 surface, without needing to expose the MoS2 flake to harsh temperatures or PLD environments. TG multilayered MoS2 NCFETs with the HZO/mica stack are fabricated and demonstrate stable NC effects and superior performance with a subthreshold swing (SS) of 49 mV/dec, ON/OFF current ratio above 107, and anticlockwise hysteresis voltages of 64 mV, which are attributed to vital contributions from the damage-free mica/MoS2 van der Waals heterojunction interface and reasonable capacitance matching between the mica dielectric and the ferroelectric HZO film. Moreover, the experimental results of the dual-gate MoS2 transistor modulated by the bottom gate show that a positive bottom-gate bias can increase drain current and decrease hysteresis voltage, and a negative bottom-gate bias can reduce SS. Therefore, the proposed approach changes the current situation that the PLD method is hardly used to fabricate TG MoS2 transistors and opens a new window for nanoelectronics. [ABSTRACT FROM AUTHOR]