Design And Investigation Of Tunneling Field Effect Transistor Based On Graphene

In recent years,with the development of integrated circuits,the size and performance of conventional MOSFET are approaching to the extreme.It is necessary to develop new alternative devices.A tunneling field effect transistor(TFET)based on band to band tunneling theory has attracted the attention of researchers for its ultra-low power consumption and wide application prospects at mesoscopic scale.However,it is found that TFET has low on-state current and poor driving performance,which limits the further application of TFET.In order to solve this problem,researchers try to find ways to improve the performance of TFET from the perspective of device structure and new materials.In this paper,the TFET based on graphene is taken as research object.By utilizing the properties of graphene,a new method of TFET optimization is proposed.The major research works as follows:1.Firstly,the characteristics of TFET and graphene are introduced.Then the working principle of TFET and the transport properties of graphene are studied in detail.On this basis,the advantages of TFET based on graphene are introduced.In order to explore device performance expediently,the computational model in the simulation software NanoTCAD ViDES is improved.As a result,the application scope is expanded.2.Structural design and parameter optimization of TFET based on graphene are included in this part.The effects of gate structure,gate dielectric,channel length,and doping concentration on the performance of TFET are investigated in detail.The results show that double gate structure,the gate dielectric with small thickness or high dielectric constant,and high source doping can effectively improve on-state current of TFET.The proper channel length can reduce off-state current.The drain doping helps to reduce the bipolarity of TFET.3.It is proposed to use graphene nanoribbon heterojunctions to enhance the performance of TFET.According to the band gap characteristics of graphene nanoribbon,two graphene heterojunctions,zigzag ribbon and cruciform ribbon,are designed as the conductive channel of TFET.Simulation studies on the device show that both heterojunctions can boost the on-state current of TFET.In addition,the band gap of zigzag strip changes with device status,which can be used to further optimize device switching characteristics.