The Physical Module And Properties Optimization Of Pb Zr_1-xTi_xO₃ Gated Negative Capacitance Ferroelectric Field Effect Transistor

In recent years,ferroelectric gate field-effect transistor(FeFET),has received widely attention,as a storage unit for ferroelectric random access memory(Fe RAM),and is currently regarded as one of the most ideal memory with clear advantages such as high speed writing,non-volatility,low power dissipation and compatible with the process of integrated circuit(IC).With the continuous improvement of chip integration,power consumption has become a serious problem,when the Fe FET used as a Fe RAM chip also need to overcome the power problem,and some researches show that the negative capacitance effect of FeFET can effectively reduce the power consumption.Based on this problems,in this thesis,the negative capacitance effect of FeFET is mainly investigated by combining the physical modeling and numerical analysis.The main contents and conclusions are as1.Based on the Landau-Ginzburg-Devonshire Phenomenological theory,the Poisson's equation,and the current continuity equation,the physical model of PZT-DG-NC-FET has been set up.Then,the electrical characteristics of PbZr1-xTixO3 gated negative capacitance ferroelectric field-effect transistor were investigated by considering the titanium component x.The derived results demonstrated that the properties of the NC FeFET can be tuned by the value of x.With x increases from0.035 to 0.065,The negative capacitance regime which allows for amplified surface potential and steeper subthreshold characteristics were significantly affected by the value of x.It is expected that this result can provide a new way to solve the problem of power consumption of FeFET,It also has some significance for its application in fast switching.2.Based on the physical model of chapter 2,the electrical characteristics of PZT gated negative capacitance ferroelectric field-effect transistor were investigated by considering the thickness of ferroelectric layer.The derived results demonstrated that the enhanced negative capacitance effect,up-converted semiconductor surface potential and low subthreshold swing can be realized with appropriate thicknesses of ferroelectric layer.So that low-power operation of the transistor can be achieved.It is expected that this result can provide a new way to solve the problem of power consumption of FeFET.3.Based on the physical model of chapter 2,the electrical characteristics of PZTgated negative capacitance ferroelectric field-effect transistor were investigated by considering the thickness of insulator layer.The derived results demonstrated that as the thickness of the insulating layer increases,the voltage amplification capability will deteriorate,the gate capacitance peak will decrease,and the subthreshold characteristic will deteriorate.So we can reduce the thickness of the insulation layer to improve the voltage amplification capability and enhance the negative capacitance effect.It is expected that this result can provide a new way to solve the problem of power consumption of FeFET.4.Based on the physical model of chapter 2,the electrical characteristics of PZT gated negative capacitance ferroelectric field-effect transistor were investigated by considering the thickness of semiconductor.The derived results demonstrated that the semiconductor surface potential and subthreshold swing can't be tuned by the thicknesses of semiconductor.So,we can investigate the electrical characteristics of PZT gated negative capacitance ferroelectric field-effect transistor by other factors without the thickness of semiconductor.It is expected that the derived results can offer useful guidelines for the application of FETs.