Improved electrical performance of multilayer MoS2 transistor by incorporating Al into host HfO2 as gate dielectric

The effects of incorporating Al into HfO2 as gate dielectric on the back-gated MoS2 transistor are investigated. Hf0.5Al0.5O as gate dielectric exhibits excellent electrical characteristics: on/off ratio of 1.8 × 107, carrier mobility of 49.3 cm2/(V s), subthreshold swing of 118 mV dec−1, interface-state density of 2.3 × 1012 eV−1 cm−2, due to the Al incorporation into the HfO2 can passivate the defective states induced by oxygen vacancies and improve the dielectric densification and uniformity to obtain an excellent MoS2/Hf1-x Al x O interface. Besides, the intrinsic carrier mobility of 100 cm2 V−1 s−1 and contact resistance of 11.1 kΩ/μm indicates that the contact resistance is a main factor limiting the mobility.