Charge Trap Memory Based on Few-Layered Black Phosphorus

TL;DR

This paper demonstrates a novel non-volatile memory device using few-layer black phosphorus with a large hysteresis and exceptional retention, leveraging a 3D charge-trap stack with HfO2 for flexible electronics.

Contribution

First demonstration of black phosphorus-based charge-trap memory with large hysteresis and high endurance using a 3D Al2O3/HfO2/Al2O3 stack.

Findings

Memory window exceeds 12 V due to HfO2 trapping ability.

Device retains ?25% charge after 10 years, outperforming MoS2 flash memory.

High endurance, stable retention, and high on/off ratio achieved.

Abstract

Atomically thin layered two-dimensional materials, including transition-metal dichacolgenide (TMDC) and black phosphorus (BP), (1) have been receiving much attention, because of their promising physical properties and potential applications in flexible and transparent electronic devices . Here, for the first time we show non-volatile chargetrap memory devices, based on field-effect transistors with large hysteresis, consisting of a few-layer black phosphorus channel and a three dimensional (3D) Al2O3 /HfO2 /Al2O3 charge-trap gate stack. An unprecedented memory window exceeding 12 V is observed, due to the extraordinary trapping ability of HfO2. The device shows a high endurance and a stable retention of ?25% charge loss after 10 years, even drastically lower than reported MoS2 flash memory. The high program/erase current ratio, large memory window, stable retention and high on/off current ratio, provide a promising route towards the flexible and transparent memory devices utilising atomically thin two-dimensional materials. The combination of 2D materials with traditional high-k charge-trap gate stacks opens up an exciting field of nonvolatile memory devices.