Nanodiamonds are a circuit’s best friend

Ashley N. Paddock, ashley.paddock@photonics.com

Diamonds are now an electrical engineer’s best friend: The iridescent, sturdy diamond can improve the design of computer chips and electronic circuitry for extreme environments.

Vanderbilt University engineers have developed the basic components needed to create microelectronic devices out of thin films of nanodiamond, including diamond versions of transistors and, most recently, logic gates.

Diamond-based devices have the potential to operate at higher speeds and require less power than silicon-based devices. Nanodiamond circuits are a hybrid of old-fashioned vacuum tubes and modern solid-state microelectronics, combining some of the best qualities of both technologies.

Graduate students Nikkon Ghosh (front) and William Paxton working in the cleanroom where nanodiamond circuits are prepared. Courtesy of Joe Howell, Vanderbilt University.

Potential applications for the new devices include military electronics, circuitry that operates in space, ultrahigh-speed switches, ultralow-power applications, and sensors that operate in high-radiation environments at extremely high temperatures (up to 900 °F) and extremely low temperatures (down to –300 °F).

The design uses diamond film, but incorporating it is not expensive. Because of their small size, about 1 billion devices can be fabricated from a 1-carat diamond. The engineers used a chemical vapor deposition method to create the films from methane and hydrogen. As a result, the cost of producing the nanodiamond device should be competitive with silicon, the scientists say.

Professor Jimmy Davidson stands behind a chemical vapor deposition machine used to create nanodiamond transistors. Courtesy of Daniel Dubois, Vanderbilt University.

Professor Jimmy Davidson said the new concept offers an alternative approach to achieving electronic function in extreme environments – not currently possible or compromised by the limitations of silicon, silicon carbide and others. These include down-hole oil exploration, sensors and electronics, and nuclear environs such as solar, deep space, reactors and electromagnetic pulses. He is hopeful that, with maturation, the devices will improve power electronics by being drivable to higher currents and temperatures.

The research was supported by grants from the US Army and appeared in the Aug. 4 issue of Electronics Letters (doi: 10.1049/el.2011.2314).