Diamond power devices are a gem of an idea

A group of UK companies has embarked on a DTI-backed project to develop novel power components based on semiconducting diamond materials. They believe that the three-year Carbon Power Electronics (Cape) programme could result in a new generation of power semiconductors that outperform those based on materials such as silicon or silicon carbide, especially at high temperatures and voltages.

The project, being funded by the UK Department of Trade and Industry under its Basic Technologies for Industrial Applications programme, will bring together an industrial diamond specialist, Element Six, the power semiconductor developer Dynex, and Cambridge University`s Department of Engineering.

The project is based on a new technique for synthesizing electronic-grade diamond, developed by Element Six. "Diamond has long been recognised as the ultimate wide band-gap semiconductor, but until recently it has not been considered a viable material for electronics," says the Ascot-based company`s r&d manager, Dr Steve Coe. With the new chemical vapour deposition technique, "the prospects for diamond semiconductor components are now very real," he continues. "We have a unique opportunity to introduce a new technology to the field of power electronics."

"A limitation with today`s semiconductors, such as silicon, is that high voltage or high temperature can cause the material to switch its conducting state in an uncontrolled manner," explains Gehan Amaratunga, professor of electronic engineering at Cambridge.

With wide band-gap materials, such as diamond, much higher energies are needed to change the semiconducting state. Diamond therefore retains electronic control at higher voltages and temperatures than silicon.

"Add to this the best thermal conductivity of any material, and the highest carrier capability of any wide band-gap semiconductor," Amaratunga continues, "and diamond offers the possibility of electronic devices with far superior performance than any known today."

According to Dr Paul Taylor, Dynex`s chief technical officer, the group aims to produce prototype devices that will confirm the benefits of the new materials. Several potential applications have already been identified. "This could prove to be a rare opportunity to implement a market-defining technology," Taylor declares.