In a very difficult climate for U.S. solar companies, one Boston-area startup has made some significant progress in solar technology. SiOnyx, a Beverly, MA-based semiconductor company known for its “black silicon” approach to various applications, including solar cells, is reporting today that it has achieved an overall efficiency that is higher than the current industry standard, and more uniform from cell to cell—and that this result should have commercial impact soon.
“We have a solar program that’s starting to have tremendous results,” says James Carey, the company’s co-founder and principal scientist.
When we last caught up with SiOnyx almost exactly a year ago, the company had just closed $12.5 million in second-round venture financing. (Its investors include Polaris Venture Partners, Crosslink Capital, and Vulcan Capital.) The firm’s black silicon technique involves peppering silicon wafers with ultrafast laser pulses to roughen their surface, such that they become more efficient at absorbing near-infrared light.
That means a solar cell made with the technique will absorb more light and, in principle, produce more electricity than one made of conventional silicon. But until now, the company hadn’t proven this to be the case in a manufacturing setting. In partnership with German research institute and chip foundry ISC Konstanz, SiOnyx has demonstrated an improvement of 0.3 percent in absolute efficiency—the ratio of electrical energy out to light energy in—over industry-standard silicon. (The cutting edge of conventional solar cells is just over 17 percent efficiency.)
Big deal? Well, it turns out that 0.3 percent represents roughly a year’s worth of progress in the traditional solar cell industry, says Chris Vineis, the company’s director of solar technology. “Existing solar cell manufacturers can take this [SiOnyx process], drop it into their line, and get an efficiency boost,” he says.
The SiOnyx technique is inserted in the early part of the conventional silicon wafer processing. The method substitutes lasers for chemicals in the initial texturing step, but the rest of the manufacturing process is untouched, Vineis says. The end result, he says, is slightly higher efficiency, potentially thinner wafers that use less silicon, and more uniform efficiency across wafers. Together, those factors could lead to savings of “several cents per watt,” Vineis says.
But it’s still early days for the company’s solar business. SiOnyx, which has nearly 30 employees and says it is still growing, is in initial conversations with potential solar customers. The idea is the company will license its black silicon process to solar cell manufacturers. “We’re not actually making solar cells, which is good for us,” Vineis says. “The industry is in a very tough spot.”
Solar is actually only a small part of the startup’s overall business, however. SiOnyx plans to make about 80 percent of its revenues on its image sensor products and 20 percent on its solar process, Carey says. The image sensor application, which I wrote about last year, uses the same black silicon technology to create fundamentally more sensitive cameras and other imaging equipment.
“We’re more than a one trick pony,” Carey says.
