Russian Scientists Invent a Graphene-Based Flash Memory

PHOTO by From GTRK Novosibirsk news broadcast

Researchers at the Rzhanov Institute of Semiconductor Physics, the Siberian Branch of the Russian Academy of Sciences, found out that graphene-based flash memory cards allow for a faster write/erase procedures and have a longer shelf life than similar products based on other materials, the Science in Siberia website reports.

The institute examined whether multilayer graphene structures could be used in flash memory elements. An electric charge is introduced and stored in the graphene memory environment. In addition, the flash memory card needs to have silicone dioxide tunneling and blocking with high dielectric permeability.

Memory card efficiency (write/erase function and charge storage time) depends on the work function of the memory environment, i.e. the amount of energy needed to remove an electron from a substance. Multilayer graphene is unique in that respect as its work function is approximately five electronvolts. As a result, the potential barrier is higher at the boundary between the graphene and silicon dioxide layers and amounts to about four electronvolts. This effect constitutes the basis of the research in question.

Multilayer graphene pressed between the tunneling and blocking is a potential pit for the charge to be stored, thus presenting opportunities to optimise the memory card geometry, e.g. to use a thinner tunneling layer. Comparatively, the potential barrier between a silicon and silicon dioxide layers amounts to as little as 3.1 electronvolts.

As a result, flash memory based on charge stored in silicon clusters has thicker tunneling and blocking layers, which inevitably results in a slower write/erase function. However, mass production of graphene-based memory cards is not going to begin any time soon as the research team are still working on prototypes.