Fabrication And Performance Analysis Of Field Effect Transistor Based On MoS₂

With the progress of Moore's Law slows down,silicon-based integrated circuits that have been in fast iterations for decades of years are now faced with new challenges.The device scaling will probably meet the physical limit when the technology node comes to 5 nm,where quantum effect will hinder the miniaturization process.2D semiconductors,as a promising material to extending Moore's Law,have attracted considerable attention.Molybdenum disulfide?MoS₂?is a kind of Transition-metal dichalcogenide.With atomic thickness?0.65nm?and proper bandgap?1.2eV for multilayers and 1.8eV for monolayer?,MoS₂ is believed with better potential than graphene in applied semiconductor technology.In this manuscript,the author focus on the field effect transistors based on MoS₂.The material characteristics are described firstly,followed with the development history of MoS₂ transistors.After a brief introduction of material preparation methods and characterization methods,the following chapters presents the optimization of MoS₂ device and the characterization of the device.The band alignments between Mo S₂ and several dielectric materials were discussed,and the optimal preparation and correlation performance of MoS₂ back gate device were analyzed.The main points of this paper include:?1?The energy band alignment between MoS₂ and a variety of dielectric materials was characterized by high resolution x-ray photoelectron spectroscopy?XPS?.Which provide the basis for the preparation of field-effect transistor based on MoS₂.?2?By scaling down the thickness of the SiO₂ gate oxide layer in a back-gated MoS₂ FET,the subthreshold swing is improved greatly,which is the best performance?86mV/dec?reported by similar works so far.?3?The advantages and disadvantages of High-K dielectrics are discussed and compared with that of SiO₂.This work provides an optimization scheme for the preparation of the same kind of devices.?4?The phenomenon and cause of the hysteresis of back-gate transistor with a bare channel are analyzed,and the reliability of the device test is discussed.The problem of hysteresis is very important in MoS₂ back-gate transistors and other associated sensing devices.?5?The factors including back-gate leakage,temperature vatiation and contact resistance that will influence MoS₂ devices'performance are discussed and analysed.