Research On Independent Gate TFET Device And Its Basic Logic Circuit

Driven by the strong demand in the mobile portable electronics market,low power consumption will become a key indicator of chip design.Although power reduction can be achieved at the circuit and system levels,the fundamental limitation of overall chip energy efficiency still lies in the working principle of metal oxide semiconductor field effect transistors(MOSFETs)and their constant physical limits,namely Boltzmann distributed carriers cannot make the subthreshold swing of the MOSFET below 60 m V / dec.This physical limit ultimately determines the lowest energy consumption available with complementary metal-oxidesemiconductor(CMOS)technology.Tunneling field effect transistors(TFETs)have become one of the most promising candidates for exceeding the energy consumption limits of traditional MOSFETs.TFETs that use a current transfer mechanism with inter-band tunneling to achieve steeper switching characteristics than MOSFETs are capable of operating at lower threshold voltages(VTH)and lower supply voltages(VDD).However,due to the working principle of inter-band tunneling,TFETs have a lower on-current,which has become a challenge for TFET devices.In this paper,the structure and materials of the TFET are studied to increase the TFET on-current.The paper proposes high-threshold and low-threshold independent gate TFET devices,which are used flexibly in circuit design and increase circuit integration density.The main innovations of this article are as follows:1.An independent gate TFET device was constructed.And we optimize the devive with the switching current ratio,sub-threshold swing,and on-current as the optimization goals on process parameters(source,drain concentration,etc.),device structure(gate cover structure,pocket layer structure,etc.),device materials(III-V materials,silicon germanium materials,etc.).The paper realizes new devices with high threshold independent gate TFET and low threshold independent gate TFET with good performance.2.The simulation model of Hspice for high threshold and low threshold independent gate TFET devices is established and verified by the simulation of unit circuit,which proves that the proposed simulation model is accurate and effective.3.The basic unit circuit is designed by using high threshold and low threshold independent gate TFET devices.Compared with gate level circuits of the same gate TFET devices,it is proved that the proposed new device has greater advantages in reducing power consumption.The TCAD simulation results show that the independent gate high-threshold TFET device meets the design expectations of switching logic,that is,the proposed independent gate lowthreshold TFET device can express OR logic,which is equivalent to two discrete devices in parallel;the independent gate high-threshold TFET device can express The output and logic are equivalent to two discrete devices connected in series.In addition,HSPICE simulation results show that the basic logic gate circuit based on the high and low threshold independent gate TFET devices can reduce the energy consumption delay product by at least about 20% compared to the same gate TFET basic logic gate circuit,and the overall circuit performance is improved.In addition,the independent gate TFET circuit can effectively reduce the number of transistors in the circuit and reduce the layout area.The research results can provide a certain theoretical basis for industrial production.