The effects of treating the HfO2 gate dielectric in different plasmas (O2, N2, and NH3) on the electrical characteristics of a back-gated MoS2 transistor are investigated. It is found that the electrical properties of the device improved after HfO2 is treated by these plasmas, in which NH3-plasma treatment results in the best electrical characteristics: high ON-OFF ratio of 1.26times 107 , high extrinsic carrier mobility of 61.5 cm2/ textVcdot texts , small subthreshold swing (SS) of 111 mV/dec, low interface-state density of 2.79times 1012 eV -1,,cdot cm-2, and small hysteresis of 43 mV. These should be attributed to the incorporation of more N into the HfO2 film by the NH3 plasma to repair the oxygen vacancies and increase the k value of the HfO2 film. Moreover, H from the NH3 plasma effectively passivates the dangling bonds at/near the HfO2/MoS2 interface, thus creating an excellent MoS2/HfO2 interface.
- Carrier mobility
- interface-state density
- MoS₂ transistors
- plasma-treated HfO₂
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering