Solution‐processed high‐k oxide dielectric via deep ultraviolet and rapid thermal annealing for high‐performance MoS2 FETs

Abstract

So far most of MoS2‐based devices have been demonstrated on oxide gate dielectrics (e.g., SiO2, Al2O3, HfO2, etc) deposited by vacuum process or on polymer gate dielectrics. In this study, we report electrical characteristics of multilayer MoS2 transistors fabricated on solution‐processed high‐k AlOx gate dielectric via deep ultraviolet (DUV) activation in combination with rapid thermal annealing process at 250 °C. The solution‐processed AlOx sol–gel film exhibited low leakage current of about 1.49 μA cm−2 at 1 MV cm−1 and a relative dielectric constant (k) of ∼6.1 at 1 kHz. The fabricated MoS2‐FETs exhibit median field‐effect mobility of ∼23.3 cm2 V−1s−1, threshold voltage of ∼ 0.79 V, subthreshold slope of ∼0.30 V dec−1, and on/off current ratio of ∼107. The electrical performance can be further improved by optimizing the AlOx sol–gel film as well as the device structure, and the result implies that the solution‐processed high‐k AlOx is promising for TMDC–based device applications.