The Influence Of Capacitance Matching On The Performance Of Negative Capacitance Transistors

Compared with traditional metal oxide semiconductor field effect transistors(MOSFET),Negative Capacitance Field Effect Transistor(NCFET)has many advantages.It has attracted great attention due to its low sub-threshold swing and high drive current,and is considered a promising technical solution for the next generation of low-power integratedcircuits.In this study,the capacitance matchingof NCFET based on fully depletedsilicon-on-insulator(FDSOI)technology is investigated using technology computer-aided design(TCAD)simulation.First,this article introduces the theoretical mechanism of negative capacitance in detail and uses the TCAD Sentaurus tool to model the FDSOI device process,and couples the ferroelectric capacitor model to the FDSOI device to form a negative capacitance transistor.Secondly,this paper analyzes in detail the influence of capacitance matching caused by ferroelectric material parameters(coercive electric field Ec,remanent polarization Pr)on negative capacitance transistors.This article defines the Pr/Ec ratio(R_PE)for the first time as a parameter to measure the matching effect.The results show that good negative capacitance matching is closely related to R_PE.In addition,the experimental results observe that a negative capacitance transistor with a two-layer ferroelectric structure can effectively improve capacitance matching in different working regions compared with a single-layer ferroelectric layer,thereby increasing the on-current and reducing the subthreshold region.As a result,the device has a higher switching current ratio(I_ON/I_OFF).Then,in view of the changes in the gate voltage of the negative capacitance transistor caused by the drain voltage,this paper studies the drain-induced barrier reduction effect(DIBL)and the negative differential resistance(NDR)effect in detail.The simulation results show that DIBL tends to be consistent with the same R_PE,despite exhibiting different current intensities in the strong inversion region.With regard to different R_PE,the DIBL effect decreases but the NDR effect increases as R_PE decreases.After that,a detailed analysis of the uneven polarization of ferroelectric materials caused by the increase in drain voltage is carried out to adjust the capacitance matching to improve DIBL and NDR and optimize the performance of NCFET.Finally,this article analyzes the dependence of NCFET on temperature.The results show that under the premise that the temperature of the ferroelectric material is lower than the Curie temperature,as the temperature rises,the degree of capacitance matching between the ferroelectric capacitance and the total capacitance of the bottom MOSFET gate decreases,which makes the subthreshold characteristics of NCFET worse,and causes the drive current and output current to drop.The work of this paper provides an intuitive and quantifiable reference basis for adjusting the capacitance matching effect to optimize NCFET performance.