The Electrical Properties Analysis Of Two-dimensional Material Field Effect Transistors

Since its birth,silicon-based electronic devices have always followed Moores law and developed rapidly.However,with the continuous reduction of device size,it has gradually become difficult to meet Moores law,let alone adapt to the development needs of the information age.Therefore,it is urgent to find new high-performance semiconductor materials to replace silicon.Graphene has very high carrier mobility,which makes it suitable for making RF devices.Mo S2 has the characteristics of natural adjustable band gap and no hanging bond on the surface,so it is suitable for the preparation of high performance field effect tube.More importantly,Mo S2 field effect tube has a good inhibition effect on short channel effect.At present,there have been a lot of experimental studies on graphene and Mo S2 field effect transistors,and the performance of the devices is constantly improved,but the research on the interface between channel material and insulating medium is still not perfect.The powerful device simulation software can easily define the material parameters such as graphene and molybdenum disulfide,which brings great convenience to process design and device simulation.Similar to graphene,hexagonal boron nitride has a twodimensional structure with high surface flatness and high carrier mobility on the boron nitride substrate.The boron nitride substrate can not only open the graphene band gap,but also improve the electrical properties of two-dimensional material field effect tubes.In this paper,the field effect transistor(FET)with boron nitride substrate and dielectric layer is established,and the factors that affect the device performance are simulated.The main contents are as follows:1)The structure and properties of graphene and molybdenum disulfide as well as their main application fields are introduced.The preparation methods and different characterization methods of two-dimensional materials are compared.The basic working principle of the field effect transistor is analyzed,various ways of opening the graphene band gap are summarized,the research progress of graphene and Mo S2 field effect transistor is summarized,and the research direction of this paper is determined.2)In the simulation software,the graphene field effect transistor on the silica substrate was modeled,and the feasibility of modeling was verified.Then,the device model with boron nitride as substrate and gate medium was established.The transfer characteristic curves and output characteristic curves of GFET devices are obtained under different bias voltages.The AC characteristics of GFET devices were simulated by using the AC small-signal model,and the relationship curve of gate capacitance with gate voltage and the RF characteristics such as cut-off frequency were obtained.The effect of trap density on device transfer characteristics was further tested.As a graphene-like material,Mo S2 also has excellent electrical properties.The effects of gate length,dielectric thickness and gate dielectric material on the electrical properties of the device are studied.Similarly,the effects of trap density and trap location on the threshold voltage of the device are studied.