IBM is reporting a scientific materials breakthrough at the atomic level that could pave the way for a new class of non-volatile memory and logic chips that would use less power than today's silicon-based devices.
The breakthrough leaves behind conventional electronic means that operate today's semiconducting devices in favor of a new way to operate chips using tiny ionic currents. These currents are streams of charged atoms that could mimic the event-driven way in which the human brain operates.
"Our ability to understand and control matter at atomic scale dimensions allows us to engineer new materials and devices that operate on entirely different principles than the silicon-based information technologies of today," said Stuart Parkin, an IBM Fellow at IBM Research.
"Going beyond today's charge-based devices to those that use minuscule ionic currents to reversibly control the state of matter has the potential for new types of devices. Using these devices and concepts in novel three-dimensional architectures could prevent the information technology industry from hitting a technology brick wall."
A Droplet of Ionic Liquid
Modern computers typically use semiconductors made with CMOS process technologies. It has long been thought that these chips would double in performance and decrease in size and cost every two years. But the materials and techniques to develop and build CMOS chips are rapidly approaching physical and performance limitations, and new solutions may soon be needed to develop higher performance and lower-power devices.
IBM research scientists showed that it is possible to reversibly transform metal oxides between insulating and conductive states by the insertion and removal of oxygen ions driven by electric fields at oxide-liquid interfaces. Once the oxide materials, which are innately insulating, are transformed into a conducting state, the IBM experiments showed, the materials maintain a stable metallic state even when power to the device is removed.
According to IBM, this non-volatile property means that chips using devices that operate using this phenomenon could be used to store and transport data in a more efficient, event-driven manner instead of requiring the state of the devices to be maintained by constant electrical currents.
IBM researchers applied a positively charged ionic liquid electrolyte to an insulating oxide material -- vanadium dioxide -- and successfully converted the material to a metallic state. The material held its metallic state until a negatively charged ionic liquid electrolyte was applied, to convert it back to its original, insulating state.
Charles King, principal analyst at Pund-IT, said IBM's advance is an interesting first step considering the industry is rapidly approaching a place where silicon will no longer be able to scale down to make smaller and smaller micro circuits. In other words, he said, it will be physically impossible to go past the atomic stage.
"IBM has come up with a way of running ionized electrolytes through the metal oxide and, depending on the type of ions running through the electrolytes, they can switch the electrolytes from being an insulator to being a conductor," King said. "When you are ready to turn them on and off you simply start running the electrolyte through it.
"From a practical standpoint, if you could make commercial products based on this, which is one big if, a computing chip could run on a tiny fraction of the electricity of today's microprocessor."