Design Of Hybrid-type SRAM Cell Based On MOSFET-TFET Devices

The popularity of today's electronic products is inseparable from the continuous development of integrated circuits,the needs of Static Random Access Memory(SRAM)with lower power consumption are growing.Although CMOS is the main technology of today's chip industry,due to the limits of Metal Oxide Semiconductor Field Effect Transistor(MOSFET)in low supply voltage,CMOS technology has been greatly affected in terms of power consumption.In the design of SRAM,the sub-threshold swing of MOSFET devices at lower operating voltages cannot be lower than 60 m V/dec,which greatly limits the use of MOSFET in SRAM in the application.Tunnel Field-Effect Transistor(TFET)can have a smaller sub-threshold swing at low power supply voltages,so they have received extensive attention in the industry.However,TFET devices have certain limitations due to their own characteristics.Unlike the bidirectional conductivity characteristics of MOSFET devices,TFET devices are unidirectionally conductive,and TFET devices also have uncontrolled forward bias pin currents,which will affect the TFET device's performance.In the application of SRAM cell,to deal with the issues of TFET device,this paper proposes a 8T MOSFET-TFET hybrid SRAM cell circuit.The details of the article are as follows:1.This article first introduces the limitations of MOSFET devices in actual SRAM cells,and then introduces the advantages and limitations of TFET devices in low-power SRAM cells.Secondly,the working principles of band-band tunneling and TFET devices are introduced,and the fundamental electrical properties such as the structure and working theory of TFET devices are specifically analyzed,and the similarities and differences between TFET devices and MOSFET devices are compared.After that,several typical TFET SRAM cell circuits are introduced,analyzing the impact of TFET device unidirectional conductivity and forward p-i-n current on the performance of SRAM cell circuits.2.In order to solve the problems of TFET devices in SRAM cell circuits,this paper proposes a new 8T MOSFET-TFET hybrid SRAM cell circuit,and introduced its circuit structure,theory in the process of reading and writing and holding,and its application in the array.The new 8T SRAM cell circuit has better performance.3.In this paper,two typical TFET SRAM cell circuits are selected for comparison with the new 8T MOSFET-TFET SRAM cell circuit.The three TFET SRAM cell circuits are simulated in terms of static noise margin,power consumption,read or write speed.The results of the proposed 8T SRAM cell is better than 7T SRAM cell in terms of static power consumption at a working voltage of 0.6V.The 7T SRAM cell is four orders of magnitude lower.Compared with the 10 T SRAM,the write delay of the new 8T SRAM is decreased by55%,and the write noise margin has also been greatly improved.The proposed 8T SRAM has superior working performance.