Research On New Tunneling Field Effect Transistor TFET

Band-to-band tunneling field effect transistor(BTB TFET)based on quantum tunneling principle is one of the future transistor development directions predicted by Intel.Its unique band-to-band tunneling mechanism and the opposite doping types of the source and drain regions make BTB TFET devices better in low power consumption.However,when facing low voltage and low power consumption applications,traditional band-to-band tunneling field effect transistors face higher control voltages,subthreshold swing degradation and higher off-state current density due to parasitic bipolar effects.Compared with BTB TFET devices,the in-band tunneling field effect transistor(IB TFET)does not need to cross the forbidden band because of its electronic transport.Instead,the conduction band on one side of the barrier layer tunnels into the the conduction band and the structure do not require the source and drain regions to be of the opposite doping type,and are isolated by the barrier layer.Therefore,it has the advantages of lowering the gate voltage,eliminating the parasitic bipolar effect,making the off-state current density extremely low,and not demanding on the manufacturing process,which may help solve the above problems.In order to solve these problems,in this paper,systematic research is performed based on silicon baseband tunneling field effect transistor(silicon-based IBTFET)and gallium nitride baseband tunneling field effect transistor(Ga N-based IBTFET).In the research of silicon-based IBTFET,the structure model of silicon-based IB TFET are firstly designed based on the principle of in-band tunneling.Then,TCAD simulation tool is used to simulate the transfer characteristics of the model structure of the IBTFET devices,and the simulation results of the transfer characteristics of the IB TFET devices are analyzed and summarized.The regularity of the influence of device material structure parameters on its electrical performance is summarized to guide the optimal design of the device: optimization of the gate dielectric material,the gate electrode material and its parameters,and selection of high dielectric constants and thinner thicknesses(2nm)Hf O2 material as the gate dielectric layer,and metal materials with higher work functions were used as the gate electrode,which can reduce the subthreshold swing SS of the silicon-based IBTFET below the ideal situation,and the off-state current density is significantly reduced.For the Ga N-based IBTFET structure,based on its in-band tunneling principle,the TCAD simulation tool is used to simulate the three-dimensional structure and transfer characteristics of the device,and the simulation results are analyzed and compared.The regularity of the influence of material structure parameters on the electrical properties of the device is summarized to guide the optimal design of the device.According to the existing problems of the current results and the summarized regularity,the corresponding optimization measures are put forward.It is worth noting that the polarization characteristics of Ga N-based IBTFET wurtzite nitride materials along the c/ (?) crystal direction have a significant asymmetric effect on the quantum transport of electrons within the band.One solution is to adjust the polarization field intensity by controlling the change of Al component in the nanowire Al Ga N/Ga N heterojunction to control the tunneling probability of carriers.Then,the doping concentration of the Al Ga N region and the magnitude of the drain voltage are optimized to improve the transfer characteristics of Ga N-based IBTFET.Finally,the silicon-based IBTFET and Ga N-based IBTFET are compared and analyzed,and their advantages and disadvantages are summarized.