Influence Of Negative Capacitance Effect On The Analog/RF Performance Of Nano CMOS Devices

The current and voltage characteristics of a MOSFET device are maily characterized by the source to channel barrier which is controlled by the gate voltage.The sub-threshold swing(SS)determines the number of carriers that can pass through the barrier.Limited by Boltzmann,SS is not less than 60m V/decade at room temperature,which has become the main obstacle to the continuous shrinking of CMOS device size.In recent years,the negative capacitance effect of ferroelectric materials has attracted the attention of many researchers,and it has been proven that it can reduce the SS of traditional CMOS devices to below 60m V/decade,thereby reducing the power supply voltage of CMOS devices in order to further reduce power Consumption.In this paper,Sentaurus TCAD technology is used to study the analog/RF performance of negative capacitance transistors(NCFET)of traditional bulk silicon technology and fully depleted silicon-on-insulator(FDSOI)technology.The main research analog/RF performance parameters include transconductance(g_m),output conductance(g_ds),gate capacitance(C_GG),cut-off frequency(f _T)and maximum oscillation frequency(f_max).First,the bulk silicon MOSFET is modeled,and the ferroelectric capacitor is coupled to the gate of the device to form a metal-ferroelectric-metal insulator semiconductor(MFMIS)structure negative capacitance transistor.The results show that NCFET is superior to ordinary CMOS devices in terms of analog/RF performance,has higher g_m and C_GG,and can reach the peak value of f _T at a lower gate voltage.And as the ferroelectric layer thickness(T_FE)increases,the channel current of the device continues to increase,and SS also decreases to below 60m V/decade.Secondly,AC small-signal analysis is carried out on the negative capacitance fully depleted silicon-on-insulator(NC-FDSOI)based on FDSOI technology,and the influence of ferroelectric parameters on device analog/RF performance is studied.The results show that the analog/RF performance parameters of NC-FDSOI are better than traditional FDSOI devices.Moreover,an appropriate increase in the coercive electric field(Ec)and remanent polarization(Pr)can not only increase the g_m,g_ds and C_GG of the device,but also reduce the voltage required for f _T and fmax to reach the peak value.Finally,the temperature dependence of the analog/RF performance of the negative capacitance transistor is simulated.The analog/RF performance of the negative capacitance transistor is better at low temperature,and the influence of temperature on the analog/RF performance of the negative capacitance transistor can be reduced by increasing Ec and Pr.When the temperature is low,the g_m and g_ds of NC-FDSOI increase significantly,and when the temperature is high,the channel current and C_GGof the device decrease,and the voltage required to reach the peak value of f _T is also larger.The work of this paper provides theoretical analysis and experimental reference for designing and optimizing the analog/RF performance of NCFET.