Analysis of Using Negative Capacitance FETs to Optimize Linearity Performance for Voltage Reference Generators

Emerging voltage reference generators (VRGs) are of great demand for low-power applications in recent years. However, keeping good linearity for VRGs in deep submicrometer process is still challenging. Negative capacitance field-effect transistor (NCFET) is an emerging device, which has been found with a negative differential resistance (NDR) phenomenon and has the potential to be applied in VRGs to optimize their linearity. Hence, the feasibility of using NCFET in an emerging ultralow-power (ULP) VRG is studied in this work. An empirical formula to describe NCFET's NDR is proposed and verified by simulation through a compact SPICE model based on the Landau-Khalatnikov (LK) equation. By adjusting the strength of NDR of NCFET, its output differential resistance can be changed and cancel out the positive differential resistance (PDR) of CMOS transistor. Therefore, the proposed NCFET-based VRG achieves higher linearity. The simulation results show that the line regulation of the NCFET-based VRG decreases from 2.25%/V to 0.21%/V ( $10\times $ ).