Startup Soraa lights up with 'LED 2.0'

The startup sees a 75 percent boost in efficiency with its LED bulb, a new material platform for bringing down the cost of LEDs for general lighting.

Martin LaMonica Former Staff writer, CNET News
Martin LaMonica is a senior writer covering green tech and cutting-edge technologies. He joined CNET in 2002 to cover enterprise IT and Web development and was previously executive editor of IT publication InfoWorld.
Martin LaMonica
3 min read
Soraa CEO Eric Kim holds the company's first LED light fixture using its 'GaN' on 'GaN' technology. Soraa

To build a better light fixture, startup Soraa started right at the foundation with a different kind of LED chip inside.

The Fremont, Calif.-based company tomorrow will come out of stealth mode and launch its first product, a spotlight which uses efficient LEDs (light emitting diodes). The MR 16 bulb replaces a 50-watt halogen and uses 12.5 watts and it offers a better beam and light quality, said Soraa CEO Eric Kim.

The bulb from Soraa, which has raised more than $100 million in venture capital, is the first in a planned line of LEDs for general lighting and lasers for projector displays.

The company was founded by a team of scientists renowned for their contributions to LEDs and lasers, notably Shuji Nakamura from University of California at Santa Barbara. In 2008, investor Vinod Khosla approached Nakamura and his colleagues Steven DenBaars and James Speck to commercialize research they had done on new materials for LEDs.

White LEDs use gallium nitride (GaN) as the active semiconductor material that gives off light when current is passed through it. Most companies make LED chips where a gallium nitride crystal is grown over a substrate of sapphire or, in the case of Cree, silicon carbide.

Soraa's LEDs are made with an active material layer of gallium nitride and a gallium nitride substrate. Having a single material leads to LEDs that can take more current and thus produce more light on a package of a given size. It also means that there's less wasted heat, which can degrade the life of LED lighting.

For the most part, the LED industry has tried to bring down the cost of LED lighting by scaling up manufacturing, Kim said. Competitor Bridgelux intends to make crystals on a silicon wafers to take advantage of existing silicon manufacturing equipment.

Kim said that the performance improvement that comes from the new material will help bring costs down quicker than ramping up volume production with existing materials. That will make LEDs more compelling for general-purpose lighting.

A gallium nitride on sapphire LED (seen above) has a lattice mismatch between the active material and substrate, compared to the gallium nitride on gallium nitride construction (below). Both images were taken with an electron microscope. Soraa

"When you have a very tight lattice match, light generation happens far more efficiently," said Kim who joined the company in 2010 after working at Intel and Samsung. "It really leads to LED 2.0 and a whole new disruptive technology curve."

Rather than supply LED lights sources to light fixture makers as is common in the lighting industry, Soraa is making its own LED fixtures as well. Being vertically integrated allows it to come to market faster with a light bulb and ensure supply of needed components for its LED chip platform.

Soraa's initial focus is commercial customers who use MR16 bulbs, which are typically used in restaurants, retail outlets, and museums. But it intends to make a set of products designed as replacements for existing bulbs, including those for consumers.

An executive from Soraa competitor Cree agreed that having the same active material as the substrate in an LED does lead to good efficiency, but the main limitation in this case is cost.

"A GaN (gallium nitride) wafer would be on the order of 50-100 times more expensive than an equivalent sapphire wafer. So while the wafer cost doesn't matter too much in the world of GaN-on-sapphire LEDs, it definitely would be a major expense for GaN-on-GaN," said Cree product marketing manager Paul Scheidt

Kim declined to say how much its new bulb cost, but said that the MR16, which will be available this quarter, will offer a payback in under a year, a benchmark it intends to target for future lighting products.