Effects Of Lattice Symmetry Breaking On The Performance Of Graphene Transistors

With the development of ultra-high density integrated circuits,when the size of transistor--the core component of chip enters the nanometer order,how to reduce the channel length and power consumption continuously while maintaining the high performance of the device is an urgent problem in the design of transistor structure currently.Graphene tunneling field effect transistors use two-dimensional materials with high electron mobility as channel materials,and generate channel currents based on quantum tunneling effect,which provides a new solution for the production of new transistor devices.This paper focuses on the structure of graphene nanoribbon TFET,obtains numerical results with NanoTCAD ViDES and discusses the changes in performance parameters such as switching current ratio and subthreshold swing under different lattice defects in order to obtain high-performance device structure.The main research content includes the following three parts.The first part focuses on software usage of NanoTCAD ViDES and development of source code.By changing the Hamiltonian matrix,different architectures can be described,the tight-binding approximation model and non-equilibrium Green's function method are used for numerical calculations.The basis of this research is modifying the relevant physical quantity expressions in the source code and outputting the numerical results of the target physical quantity according to requirements correctly.The second part discusses the effect of graphene vacancy defects on device performance specifically.By controlling the number,type,and position in the device of missing atoms,the local symmetry of the material is destroyed,and its influence on various electrical performance parameters such as device current can be observed.The third part focuses on the structural changes caused by strained graphene.The tensile deformation can change the band gap of the nanoribbons and affect the tunneling ability of carriers,thereby achieving the purpose of improving device performance.The results show that as the strain intensity increases,the off-state current of the device decreases first and then increases;And the switching current ratio of the device reaches10~5,the subthreshold swing reaches 51 mV/dec under the condition of sub-10 nm channel length.