TCAD Simulation Of Ferroelectric Inverter Based On Ferroelectric Field Effect Transistor

Silicon technology has advanced at exponential rates both in performances andproductivity through the past four decades. However the limit of CMOS technologyseems to be closer and closer and in the future we might see new devices and othertechnologies add to the CMOS performance, while maintaining a back-bone ofCMOS logic. Ferro-electricity in ultra-thin films has been investigated as a crediblecandidate for nonvolatile memory thanks to the bistability of polarization.Ferroelectric memories become the research focus of all people concerningferroelectrics because of such advantages of low power consumption, high density,high speed, antiradiation, non-volatility and so on. However, the ferroelectric circuitas the logic circuit not gets depth research. Therefore, the ferroelectric field effecttransistor with MFIS (metal-ferroelectric-insulator-semiconductor) structure andferroelectric inverter are been simulation at different material parameters as theresearch object. It can provide constructive guidance for the experiment.Firstly, based on the Structure Editor module (SDE) and the electricalcharacterister simulation module (Sentaurus Device) of Sentaurus TCAD, thepolarization and the drain current of ferroelectric field effect transistor are beensimulation,which in different electrical parameters.With an intuitive nature of theresults,we can see the impact of various parameter values on the device,mailyin(1)The gate voltage can widen the memory window of ferroectric field effecttransistor;(2) The thickness and the relative dielectric constant of insulater layer aswell as the parameters of ferroelectric layer are both have important influence to theferrelectric thin film transistor.Then, based on the model of a single device, which has been established before,the output characteristics of ferroelctric inverter are been analysized and simulated indifferent electrical and material parameters. The results show that:(1) The inputvoltage of the gate electrode mainly affects the output window of ferroelectricinverter;(2) the supply voltage only affect the output value of ferroelectric inverter,but has no effect on the window;(3) The thickness and the relative dielectricconstant of insulater layer as well as the parameters of ferroelectric layer are bothhave important influence to the ferrelectric inverter.Finally, the interface charge modeling of ferroelectric field effect transistor isdeveloped.The ferroelectric field effect transistor and ferroelectric inverter both with interfacial charge between ferroelectric thin layer and insulator are been analyzedand simulated. Combine the sheet charge model of the MOSFET, Miller polarizationmodel and Pao-Sah double integral model, the electrical properties of ferroelectrictransistor and ferroelectric can obtained in different interfacial charge. The resultsshow that:(1) in the ferroelectric transistor,the polarization of ferroelectric layer,silicon surface potential as well as drain current are simulated in differentinterfacial charge density between the ferroelectric layer and insulator layer.The thintransistor will be devastated when the interface charge desity to a certain extent;(2)in the ferroelectric inverter, we simulate the output characteristic curve of differentinterface charge concentration, the output window becomes smaller with theincreasing of the interfacial charge. The main reason is that the electricfield of theferroelectric layer is decreased by the interface charge. So, we need to try to controland avoid interface defects.