Effects of Charge Trapping at the MoS₂–SiO₂ Interface on the Stability of Subthreshold Swing of MoS₂ Field Effect Transistors

Abstract

The stability of the subthreshold swing (SS) is quite important for switch and memory applications in logic circuits. The SS in our MoS2 field effect transistor (FET) is enlarged when the gate voltage sweep range expands towards the negative direction. This is quite different from other reported MoS2 FETs whose SS is almost constant while varying gate voltage sweep range. This anomalous SS enlargement can be attributed to interface states at the MoS2–SiO2 interface. Moreover, a deviation of SS from its linear relationship with temperature is found. We relate this deviation to two main reasons, the energetic distribution of interface states and Fermi level shift originated from the thermal activation. Our study may be helpful for the future modification of the MoS2 FET that is applied in the low power consumption devices and circuits.

Keywords

• transition metal dichalcogenides (TMDCs)
• MoS₂ FET
• hysteresis
• subthreshold swing
• interface states