The Integration of Sub-10?nm Gate Oxide on MoS₂ with Ultra Low Leakage and Enhanced Mobility

摘要

The integration of ultra-thin gate oxide, especially at sub-10?nm region, is one of the principle problems in MoS₂ based transistors. In this work, we demonstrate sub-10?nm uniform deposition of Al₂O₃ on MoS₂ basal plane by applying ultra-low energy remote oxygen plasma pretreatment prior to atomic layer deposition. It is demonstrated that oxygen species in ultra-low energy plasma are physically adsorbed on MoS₂ surfaces without making the flakes oxidized, and is capable of benefiting the mobility of MoS₂ flake. Based on this method, top-gated MoS₂ transistor with ultrathin Al₂O₃ dielectric is fabricated. With 6.6?nm Al₂O₃ as gate dielectric, the device shows gate leakage about 0.1?pA/μm2 at 4.5?MV/cm which is much lower than previous reports. Besides, the top-gated device shows great on/off ratio of over 108, subthreshold swing (SS) of 101?mV/dec and a mobility of 28?cm2/Vs. With further investigations and careful optimizations, this method can play an important role in future nanoelectronics.