AbstractTransistors based on MoS₂ and other TMDs have been widely studied. The dangling-bond free surface of MoS₂ has made the deposition of high-quality high-k dielectrics on MoS₂ a challenge. The resulted transistors often suffer from the threshold voltage instability induced by the high density traps near MoS₂/dielectric interface or inside the gate dielectric, which is detrimental for the practical applications of MoS₂ metal-oxide-semiconductor field-effect transistor (MOSFET). In this work, by using AlN deposited by plasma enhanced atomic layer deposition (PEALD) as an interfacial layer, top-gate dielectrics as thin as 6 nm for single-layer MoS₂ transistors are demonstrated. The AlN interfacial layer not only promotes the conformal deposition of high-quality Al₂O₃ on the dangling-bond free MoS₂, but also greatly enhances the electrical stability of the MoS₂ transistors. Very small hysteresis (ΔV_th) is observed even at large gate biases and high temperatures. The transistor also exhibits a low level of flicker noise, which clearly originates from the Hooge mobility fluctuation instead of the carrier number fluctuation. The observed superior electrical stability of MoS₂ transistor is attributed to the low border trap density of the AlN interfacial layer, as well as the small gate leakage and high dielectric strength of AlN/Al₂O₃ dielectric stack.