Performance Improvement of HfS2 Transistors by Atomic Layer Deposition of HfO2

Hafnium disulfide (HfS
₂
) is one of the transition metal dichalcogenides which is expected to have the high electron mobility and the finite bandgap. However, the fabrication process for HfS
₂
-based electron devices is not established, and it is required to bring out the superior transport properties of HfS
₂
. In this report, we have investigated the effects of the atomic layer deposited HfO
₂
passivation on the current properties of HfS
₂
transistors. HfO
₂
passivation of the HfS
₂
surface enhanced the drain current and significantly reduced the hysteresis. Moreover, HfO
₂
passivation allows the use of a higher annealing temperature and further improvement of the drain current.