8 March 2011

Bridgelux claims first commercial-grade performance for Si-based LED

LED chip and lighting array maker Bridgelux Inc of Livermore, CA, USA (which claims to be the only vertically integrated maker of LED solid-state light sources specifically for the lighting industry) says that it has demonstrated gallium nitride-on-silicon based LED technology exhibiting luminous efficacy of 135 lumens per Watt, representing the industry’s first commercial-grade performance for a silicon-based LED.

When grown in high volume, most LED epitaxial wafers use sapphire or silicon carbide (SiC) substrates as the starting material. But large-diameter sapphire and SiC substrates are costly, difficult to process, and not widely available. As a result, production costs have inhibited the widespread adoption of LED lighting in homes and commercial buildings. However, growing GaN on larger, low-cost silicon wafers that are compatible with high-volume semiconductor manufacturing can deliver a 75% improvement in cost over existing approaches, says Bridgelux.

The 135lm/W performance was achieved at a correlated color temperature (CCT) of 4730K using a single 1.5mm power LED operated at 350mA. The LEDs have very low operating voltages, requiring just 2.9V at 350mA and <3.25V at 1A. The low forward voltage and excellent thermal resistance suit high-performance, illumination-grade applications, says the firm. Optimization of the epitaxy process on 8-inch silicon wafers will make LED manufacturing compatible with existing automated semiconductor lines.

Bridgelux says that the move to a silicon substrate will be a revolutionary step for the LED industry, and that the firm is well positioned to take advantage of the introduction of the technology. Over the past five years, Dr Steve Lester has fostered a team of materials scientists and chip design engineers at Bridgelux dedicated to GaN-on-silicon R&D. Concurrently, industry-wide R&D of GaN growth on silicon has increased rapidly. As a result, the latest GaN-on-Si performance levels reported by Bridgelux are comparable to state-of-the-art sapphire-based LEDs available 12–24 months ago. The firm anticipates the delivery of its first commercially available GaN-on-Si products over the next 2–3 years.

Bridgelux, which maintains an asset-light operating model, aims to leverage its R&D and intellectual property position in LED epitaxy to jointly manufacture silicon-based LEDs. It is currently in discussions with a number of established semiconductor firms regarding use of the many fully depreciated 8-inch semiconductor fabrication operations available around the globe.

“Bridgelux’s achievement is a significant reflection of the strength of our leadership in silicon materials and epitaxial process technology,” reckons CEO Bill Watkins. “The significantly reduced cost structures enabled by silicon-based LED technology will continue to deliver dramatic reductions in the up-front capital investment required for solid-state lighting,” he adds. “In as little as 2–3 years, even the most price-sensitive markets, such as commercial and office lighting, residential applications and retrofit lamps, will seamlessly and rapidly convert to solid-state lighting.”

Tags: Bridgelux LEDs GaN

Visit: www.bridgelux.com

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