FeFET-based Built-in Less-than Operation and Non-Volatile Comparator Design

Abstract

Ferroelectric field effect transistor (FeFET) is one of the non-volatile memories (NVMs) and offers significant advantages in Computing-in-Memory (CiM) digital circuit design. However, in existing non-volatile logic designs, the FeFET gate voltage and internal switch state are usually used as equivalent logic inputs. The different input variable forms limit the cascading and computational efficiency of the operation. To address this problem, this brief proposes a FeFET-based unit circuit, which performs built-in less-than comparison according to the gate-source voltage of FeFET. The proposed unit circuit can be combined with CMOS logic gates to implement a non-volatile comparator and can be extended to both serial and parallel fully non-volatile comparators. The simulation results indicate that compared with other non-volatile comparators, the FeFET-based comparator is more suitable for IoT applications in terms of computational efficiency and data recovery capability in power-off environments.