Concepedia

Non-volatile memory based on the ferroelectric photovoltaic effect

Rui Guo, Lü You, Zhou Yang, Zhi Shiuh Lim, Xi Zou, Lang Chen, R. Ramesh, Junling Wang

Nature Communications · 2013 · 488 citations · 20 references

Open access

TL;DR

Researchers seek a solid‑state universal memory with high density, speed, random access, and non‑volatility, but current flash memory is limited by slow programming/erasing times and low endurance. The study aims to use the strong photovoltaic effect of BiFeO3 to non‑destructively read polarization in a ferroelectric memory. They employ BiFeO3’s visible‑bandgap photovoltaic response to detect polarization orientation without disturbing the state. A 16‑cell cross‑bar prototype confirmed the feasibility of this photovoltaic readout approach.

Abstract

The quest for a solid state universal memory with high-storage density, high read/write speed, random access and non-volatility has triggered intense research into new materials and novel device architectures. Though the non-volatile memory market is dominated by flash memory now, it has very low operation speed with ~10 μs programming and ~10 ms erasing time. Furthermore, it can only withstand ~10(5) rewriting cycles, which prevents it from becoming the universal memory. Here we demonstrate that the significant photovoltaic effect of a ferroelectric material, such as BiFeO3 with a band gap in the visible range, can be used to sense the polarization direction non-destructively in a ferroelectric memory. A prototype 16-cell memory based on the cross-bar architecture has been prepared and tested, demonstrating the feasibility of this technique.