High Performance β‐Ga<sub>2</sub>O<sub>3</sub> Schottky Barrier Transistors with Large Work Function TMD Gate of NbS<sub>2</sub> and TaS<sub>2</sub>
Ki‐Tae Kim, Hye‐Jin Jin, Wonjun Choi, Yeonsu Jeong, Hyung Gon Shin, Yangjin Lee, Kwanpyo Kim, Seongil Im
Abstract
Abstract Gallium trioxide, β‐Ga 2 O 3 , has been recently studied due to its promising semiconducting properties as active material in transistors or Schottky diodes. Transistors with β‐Ga 2 O 3 channels are mostly metal oxide field effect transistors (MOSFET), and they show very negative threshold voltages ( V th ) in general. Metal semiconductor field effect transistors (MESFETs) with top gate are also reported with less negative V th . Still, β‐Ga 2 O 3 MESFETs are only a few. Here, bottom gate architecture β‐Ga 2 O 3 MESFETs using transition metal dichalcogenide (TMD) NbS 2 and TaS 2 are reported. Due to the large work functions of those metallic TMDs, the MESFETs display minimum subthreshold swing of 61 mV dec −1 , small V th of −1.2 V, minimum OFF I D of ≈100 fA, and maximum ON/OFF current ratio of ≈10 8 . Both β‐Ga 2 O 3 Schottky diodes with TaS 2 and NbS 2 display good junction stability even after 300 °C measurements in 10 mTorr vacuum. When the β‐Ga 2 O 3 MESFET with TaS 2 gate is integrated as a switching FET into an organic light emitting diode (OLED) circuit, it demonstrates long‐term leakage endurance performance, maintaining an OLED brightness higher than 58% of the initial intensity after 100 s passes since the ON‐switching point, which is even superior to the performance of conventional a‐IGZO MOSFET switch.