Minimizing the programming power of phase change memory by using graphene nanoribbon edge-contact

TL;DR

This paper demonstrates a significant reduction in programming energy for phase change memory by using graphene nanoribbon edge-contact, enabling low-power operation suitable for future in-memory computing.

Contribution

It introduces a novel graphene nanoribbon edge-contact structure that drastically reduces programming energy in PCRAM devices.

Findings

Write energy reduced to ~53.7 fJ with 3 nm-wide GNR

Endurance depends on bias polarity, with positive bias extending lifespan

Potential for low-power in-memory computing applications

Abstract

Nonvolatile phase change random access memory (PCRAM) is regarded as one of promising candidates for emerging mass storage in the era of Big Data. However, relatively high programming energy hurdles the further reduction of power consumption in PCRAM. Utilizing narrow edge-contact of graphene can effectively reduce the active volume of phase change material in each cell, and therefore realize low-power operation. Here, we demonstrate that a write energy can be reduced to about ~53.7 fJ in a cell with ~3 nm-wide graphene nanoribbon (GNR) as edge-contact, whose cross-sectional area is only ~1 nm2. It is found that the cycle endurance exhibits an obvious dependence on the bias polarity in the cell with structure asymmetry. If a positive bias was applied to graphene electrode, the endurance can be extended at least one order longer than the case with reversal of polarity. The work represents a great technological advance for the low power PCRAM and could benefit for in-memory computing in future.