A Carbide Revolution?

Earlier this week, news broke of a feat that could transform the semiconductor industry. In the August 26 issue of Nature, a Japanese research group announced that it had succeeded in making almost perfect crystals of silicon carbide. (Here’s an AP story describing the development.) Silicon carbide carries current more efficiently than the ubiquitously used silicon and can operate at much higher voltages. Silicon carbide also keeps on working at temperatures far above those at which silicon devices fail, and shrugs off radiation. But silicon carbide crystals created by conventional means have an impossibly high level of defects, so the material has never been a practical alternative to silicon for the semiconductor industry.

The new technique, developed at Toyota’s Central Research and Development Laboratories, could change all that. Called repeated a-face (RAF) deposition, it has produced results that Roland Madar of the Toyota labs describes as “spectacular” in an opinion piece in the same issue of Nature (subscription required).

The implications could be huge. Researchers in the U.S. and Sweden estimate that use of silicon carbide in control devices for power generation and distribution could eliminate the need for tens of billions of dollars worth of new power plants. Silicon sensors and controls for aircraft and automobile engine have to be isolated and shielded from heat sources, but their silicon carbide cousins wouldn’t need that sort of cosseting, resulting in substantial weight savings and gains in efficiency. In spacecraft, where extra weight is enormously costly, the virtues of silicon carbide–especially its indifference to heat and radiation–would be even more welcome. And silicon carbide components can even protect avionics equipment from interference by stray radiofrequency signals, so in the future you may no longer need to turn off all electronic equipment when your flight is about to take off.