By Don Clark

Silicon has shaken up many industries. A startup called Bridgelux says the next big target will be light bulbs.

The Livermore, Calif., company on Tuesday claimed a breakthrough in using the material to fabricate light-emitting diodes, the new-wave components that are finding a place in many lighting applications because of their superior energy-efficiency and longevity. A key barrier to their wider use is high cost–$40 price tags aren’t uncommon for 60-watt equivalent bulbs–and that’s where silicon could come in.

Most LEDs are now fabricated on substrates of relatively costly materials such as sapphire or silicon carbide. Many companies are putting most of their efforts in trying to use larger substrates of the same materials to drive down costs, says Bill Watkins, Bridgelux’s CEO.

A more radical approach is to move to silicon, the foundation of computer chips. Besides the cost advantage of the material, the approach could theoretically make use of the many older semiconductor factories that are inexpensive to operate.

Watkins, known for a high-profile stint as CEO of Seagate Technology before joining Bridgelux, says the problem is that silicon is much more difficult to work with for LED applications. The effort typically requires depositing the material gallium nitride on silicon wafers, and the results usually fall far short of the performance of LEDs made with conventional materials.

On Tuesday, however, Bridgelux said it has managed to use eight-inch silicon wafers to make components that achieved 135 lumens per watt–essentially reaching commercial-grade performance with the material for the first time. It will take two or three years to improve production yields to make the process commercially viable, but Watkins sees no barriers to using the approach to reduce production costs by 75%.

“This is a game-changer around the whole cost structure,” Watkins says. “We think we can get to $5 bulbs.”

Bridgelux doesn’t believe it is the only company working on silicon for LED applications, but thinks this is its announcement is dramatic enough to force others to disclose their progress. “This will shake everybody out,” Watkins says.

A Bridgelux engineer with a silicon wafer used in
making light-emitting diodes