Effect of Negative Capacitance in Partially Ground Plane based SELBOX FET on Capacitance Matching and SCEs

Abstract

Here in, we investigated the impact of negative capacitance in PGP-SELBOX NCFET (partial ground plane on a selective buried oxide in negative capacitance FET) over FDSOI. The ferro-electric layer is placed in the gate stack of PGP-SELBOX NCFET to generate the negative capacitance phenomenon. Ferroelectric(FE) materials are similar to dielectric materials but differ in terms of their polarization properties. FE-HFO 2 is used as ferroelectric material due to its sufficient polarization rate with high dielectric capacitance and better reliability. The effect of ferro-electric material parameters like coercive field(E c ) and remnant polarization(P R ) on the capacitance matching of NCFET are analyzed. The simulation results reveal that the R PE factor, which is the ratio of P R to E c , is closely related to better capacitance matching. In addition, the effect of variation in thickness of ferro-electric layer on the average sub-threshold swing(SS) is also explored. The relation between short channel effects ( V th rolloff and DIBL) and thickness of the ferro-electric (t fe ) for PGP-SELBOX NCFET is also analyzed. The simulation results clearly show that PGP-SELBOX NCFET is having reduced SCEs and 10 3 times better II OFF ON ratio over FDSOI NCFET. For optimized value of ferroelectric parameters average SS for proposed device is found as 50 mV/decade at t fe = 5nm which is lesser than FDSOI NCFET ( 56 mV/decade)

A negative capacitance field effect transistor with a modified gate stack and drain-side cavity for label-free biosensing

“…Given the low sensitivity of the baseline FDSOI device, as shown in earlier, we now include an optimized thickness of the FE layer (optimization discussed in appendix A, figure A1) over the pre-existing DE layer (stack of HfO 2 and SiO 2 ), thus modifying the architecture to an FE-DE stack-based NCFET, which results in effectively increasing the maximum height of the cavity. To include the effects of FE material on the device electrostatics in TCAD simulations, Landau parameters (given by Agarwal et al [58]), as shown in table 3, are used and the L-K equation [59,60] is included in the self-consistent loop of Poisson's, drift-diffusion and current continuity equations, which enables the determination of various channel electrostatic parameters.…”