Improved analog performance of FDSOI based NCFET with a ferroelectric–paraelectric–dielectric gate stack

Abstract

With the superior analog/RF performance of Planar device architectures such as Fully Depleted Silicon-on-Insulator (FDSOI) MOSFETs, it becomes important to investigate the impact of a ferroelectric material in the gate stack, resulting in Negative Capacitance (NC) behavior, on the device performance. In this work, through calibrating the FDSOI MOSFET (as the baseline device architecture) with experimental data, we compare the impact of Ferroelectric-Dielectric (FE-DE) and Ferroelectric-Paraelectric-Dielectric (FE-PE-DE) gate stacks on the electrostatics of an NCFET device for a practically realisable Metal-Ferroelectric-Insulator-Semiconductor (MFIS) structure. A suitable thickness of the Ferroelectric (FE) layer in the FE-DE stack and the maximum drain-source voltage (Vds) that can be applied (determining the power supply voltage), are identified so as to ensure that constraints such as no Negative Differential Resistance (NDR) Effects, Threshold voltage (Vthe), Sub-threshold slope (SS) invariability with drain voltage variations and Hysteresis-free behavior in transfer characteristics (Id-Vgs) are all satisfied. From the thickness of the FE layer in the FE-DE stack, the thickness of the FE layer in the FE-PE-DE stack (PE layer thickness is fixed at 1 nm) is determined where with a thicker FE layer, we obtain similar capacitance from the FE-PE-DE gate stack to that obtained from the FE-DE stack, while meeting all the constraints applied to the FE-DE stack based NCFET, enabling determination of the power supply voltage. Through showing good sub-threshold slopes (SS) with reduced output conductance (gds), resulting in improved dc gain (gm/gds) and improved linearity parameters (gm2 and gm3) along with scaling of power supply, an FE-PE-DE stack shows better analog performance, with lower power consumption, compared to an FE-DE stack, for an FDSOI NCFET, at 14 nm gate length.

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

“…PE 1 × 10 −3 cm 3 FC −1in the optimized FE-DE stack. This equivalence in negative capacitance behavior between the FE-DE stack and the FE-PE-DE stack and optimization has been reported recently[62].The Landau parameters of a PE material (shown in table5) are identical to FE material (see table3…”

“…From figure A6(a), it can be clearly seen that the comparison of C gg shows no change at lower gate voltage, while a slight change at higher gate voltage can be attributed to differences in the Landau parameters β and γ of the FE-DE and FE-PE-DE stacks. Also, in figure A7( This concept of equivalent capacitance in the FE-DE and FE-PE-DE stacks for an empty cavity has been reported recently in [62].…”