Clear future for memory

A group of scientists at the Korean Advanced Institute of Science and Technology (KAIST) have fabricated a working computer chip that is almost completely clear — the first of its kind.

The technology, called transparent resistive random access memory (TRRAM) is similar in type to existing technology, complementary metal-oxide semiconductor (CMOS) memory — common commercial chips that provide the data storage for USB flash drives and other devices.

Like CMOS devices, the latest chip provides 'non-volatile' memory. Unlike CMOS devices, however, the TRRAM chip is almost completely clear.

Why is transparency important? Clear electronics may make a room or wall more spacious by allowing electronic devices to be consolidated and stacked in small clear spaces. The technology may also enable the development of clear computer monitors and televisions that are embedded inside glass or transparent plastic. The Korean team is also developing a TRRAM using flexible materials.

"It is a milestone in transparent electronic systems," says researcher Jung Won Seo, who is the first author on the paper.

"By integrating TRRAM devices with other transparent electronic components, we can create a total see-through embedded electronic system."

Technically, TRRAM devices rely on an existing technology known as resistive random access memory (RRAM), which is already in commercial development for future electronic data storage devices.

RRAM is built using metal oxide materials, which are very transparent. What the Korean team did was to build a chip by sandwiching these metal oxide materials between equally transparent electrodes and substrates.

According to the Korean team, TRRAM devices are easy to fabricate and may be commercially available in 3–4 years. Don't expect them to replace existing CMOS devices, however. Instead, Seo predicts, the new transparent devices will drive electronics in new directions.

"We are sure that TRRAM will become one of the alternative devices to current CMOS-based flash memory in the near future after its reliability is proved and once any manufacturing issues are solved," says Prof Jae-Woo Park, who is Seo's co-advisor and co-author on the paper.

He adds that the devices have the potential to be manufactured cheaply because any transparent materials can be used as substrate and electrode. They also may not require rare elements such as Indium.