A new type of super-fast memory is on the cards, thanks to the creation of the first purely silicon oxide-based Resistive RAM memory chip that can operate in ambient conditions.
Resistive RAM – or ‘ReRAM’ – chips are based on materials whose electrical resistance changes when a voltage is applied, and they ‘remember’ this change even when the power is turned off.
They promise much greater memory storage than current technology such as Flash memory, and need much less energy and space.
Now, a UCL team has developed a new structure composed of silicon oxide, which performs the switch in resistance much more efficiently than ever before. In the new material, filaments of less-resistive silicon are formed within the solid silicon oxide. The presence or absence of these filaments represents the switch from one state to another.
The chip doesn’t require a vacuum to work, and is therefore potentially cheaper and more durable. It could also be used in touch screens and mobile devices.
“Our ReRAM memory chips need just a thousandth of the energy and are around a hundred times faster than standard Flash memory chips,” says UCL’s Dr Tony Kenyon.
“The fact that the device can operate in ambient conditions and has a continuously variable resistance opens up a huge range of potential applications. We are also working on making a quartz device with a view to developing transparent electronics.”
The UCL devices can also be designed to work as memristors, withcontinuously variable resistance that depends on the last voltage that was applied. This is an important property that allows the device to mimic how neurons in the brain function.
The development of a silicon oxide memristor is a huge step forward because of the potential for its incorporation into silicon chips, says the team.
The new ReRAM technology was actually discovered by accident, while engineers were working on using the silicon oxide material to produce silicon-based LEDs – and noticed that their devices appeared to be unstable.
They then discovered that the material wasn’t unstable at all, but flipped between various conducting and non-conducting states very predictably.
“The potential for this material is huge,” says UCL’s Adnan Mehonic.
“During proof of concept development we have shown we can programme the chips using the cycle between two or more states of conductivity. We’re very excited that our devices may be an important step towards new silicon memory chips.”