UCL makes ultra-fast ReRAM chip breakthrough

Scientists have made steps towards ultra-fast ReRAM chips that could soon be used in memory devices, as well as potentially finding applications in CPUs.

Researchers at University College London claim to have created a purely silicon oxide-based ReRAM chip that can operate in ambient conditions, with much more efficient switching.

The various types of memory such as flash, SRAM or DRAM, or countless others, are all highly specialised in their abilities. Each has their upsides and downsides and generally find themselves tailored towards certain applications. DRAM speed, for instance, is counterbalanced by its leaky capacitors and volatility.

However, researchers are looking towards a wide variety of potential technologies that could offer the full range of benefits including high speeds, non-volatility and dense storage.

Resistive RAM or ReRAM memory chips are one of them.  ReRAM chips are based on memristor technology that is able to ‘remember’ resistance changes when a voltage is applied and then turned off.

The researchers say that the ReRAM memory chips need just a thousandth of the energy than standard flash memory chips, and are roughly 100 times faster.

The team at UCL developed the new ReRAM structure by accident while attempting to produce silicon based LEDs.  Up until now, ReRAM has been developed using metal oxides which are more difficult to produce and are less easily integratable.

Instead, the team came up with a silicon oxide device that can quickly and predictably form filaments of silicon that change resistivity, meaning that the semiconducting materials can ‘switch’ from one state to another.

The chips could be produced transparently which would allow, among other applications, use in see-through smartphone touch screens. 

The team is already in talks with major semiconductor companies with regards to the patented device. It is not surprising considering that ReRAM has already piqued the interest of the likes of Toshiba, Sharp and Elpida.  

One of the researchers, Tony Kenyon, told TechEye that firms have been working on releasing metal oxide based devices – citing Hynix as an example – but the silicon versions will take up to three years to become available.

According to Kenyon, ReRAM memory has been benchmarked against flash memory, and offers significant benefits.

“It is at least a hundred times faster than flash, and  the energy required to switch is very very low, by a factor of ten thousand or so,”  Kenyon said, speaking with TechEye.

“The other nice thing is that our devices can be stacked in three dimensions – it is potentially very high density,” he said.

With memristor properties of variable resistance, which makes the device behave like a neuron, it could be possible to perform both CPU and memory tasks, he said.

“In a conventional processdor you would have processing unit, and the majority of chip nowadays is in memory, and the logic processor will be moving data in and out of memory, processing it and moving it out again,” Kenyon said.

“Using our devices you can leave the devices where it is, you don’t have to move it around so potentially it is much faster and much more efficient,” he said. “It provides both functions.”