Research And Design Of Negative Differential Resistance Type And Memristive Digital Circuit

With the rapid development of microelectronic technology,improving the integration degree of integrated circuits(IC)has become an urgent problem to be solved.Two ways will solve this problem effectively.One is to reduce the size of a single device in the process;the other is to develop new devices with excellent functions and small sizes.But the first way will cause a series of functional problems.Therefore,in recent decades,scholars at home and abroad have devoted themselves to researching and developing various new types of negative resistance devices and applying them to digital or analog circuits,which has improved the utilization of time and space in the circuit.This paper first introduces the more mature negative resistance device resonant tunneling diode RTD(RTD,Resonant Tunneling Diode),including its structure,I-V characteristics,etc.,and elaborates several equivalent models of RTD and its working principle.RTD has attracted much attention due to its unique negative resistance characteristics,it also has hysteresis characteristics in the negative resistance region.This paper analyzes the hysteresis characteristics of the RTD negative resistance region and designs a hysteresis unit circuit based on NDR(Negative Differential Resistance).The output characteristic curve of the hysteresis circuit is similar to the hysteresis curve of the memristor.After briefly introducing the circuit characteristics and output characteristics of the memristor,the third chapter of this paper compares the similarities of the two types of devices and analyzes the feasibility of their cross-application.Based on the above theory,this paper uses the NDR characteristics of RTD to design an improved R-HBT-based(HBT,Heterojunction Bipolar Transistor)memristor.The memristor not only presents a tight hysteresis curve in its output characteristics,very closely to the I-V curve of the ideal memristor,and it can be adjusted and controlled.Because of the simple circuit structure,the hardware experimental circuit is also relatively easy to implement.The NDR memristor designed in this paper can also be used in the design of logic circuits.Based on the analysis of the traditional MRL series logic gates,the R-HBT-based negative resistance memristors are used to design the binary logic.AND gate,OR gate,simulation test results verify the correctness of the design.At the same time,based on the analysis of the second type of CMOS gate circuit with resistance,this paper also designs three-valued NOR gate,three-valued NAND gate,and three-valued NOR gate based on improved R-HBT-based memristor.Finally,this paper designs a two-input three-value D-type latch using a 1-of-2 data selector,and performs simulation tests in the PSPICE software.