Scalable CMOS-BEOL compatible AlScN/2D Channel FE-FETs

TL;DR

This paper demonstrates scalable, BEOL-compatible ferroelectric FETs with 2D MoS2 channels and AlScN dielectrics, achieving high memory windows, excellent ON/OFF ratios, and stable endurance suitable for 3D integration in advanced computing.

Contribution

It introduces a novel BEOL-compatible FE-FET architecture using 2D MoS2 and AlScN, achieving high performance and scalability for memory integration.

Findings

Memory window > 7.8 V

ON/OFF ratio > 10^7

Stable retention up to 20000 seconds

Abstract

Intimate integration of memory devices with logic transistors is a frontier challenge in computer hardware. This integration is essential for augmenting computational power concurrently with enhanced energy efficiency in big-data applications such as artificial intelligence. Despite decades of efforts, reliable, compact, energy efficient and scalable memory devices are elusive. Ferroelectric Field Effect Transistors (FE-FETs) are a promising candidate but their scalability and performance in a back-end-of-line (BEOL) process remain unattained. Here, we present scalable BEOL compatible FE-FETs using two-dimensional (2D) MoS2 channel and AlScN ferroelectric dielectric. We have fabricated a large array of FE-FETs with memory windows larger than 7.8 V, ON/OFF ratios of greater than 10^7, and ON current density greater than 250 uA/um, all at ~80 nm channel lengths. Our devices show stable retention up to 20000 secs and endurance up to 20000 cycles in addition to 4-bit pulse programmable memory features thereby opening a path towards scalable 3D hetero-integration of 2D semiconductor memory with Si CMOS logic.