LED Substrate Surprises

Last week at the Taiwan Photonics Festival, Samsung made the announcement they have successfully produced HB-LEDs on 8” sapphire wafers. As most industry leaders are moving to 6”, this step could signal a disruptive era in cost reduction with widespread implications. A move to 8” further distances those still at 2”, 3” and 4” from the price leaders and makes the vast supply of used 8’ equipment (PECVD, steppers, etch, cleaning) for silicon more-readily available for LED fabs.

The announcement may be related to Monocrystal’s cryptic announcement in February that they have supplied 8-inch-diameter, c-plane, epi-ready sapphire substrate to an unnamed LED maker. Monocrystal, the Stavropol, Russia-based sapphire wafer supplier, has been supplying 8-inch sapphire substrates for R&D on RFIC application for two years, but the LED interest in 8” was a bit of shocker.

In January, Rubicon Technology announced 12-inch sapphire substrates were now available at various diameters up to 12 inches, specifically mentioning LED, but without a customer acknowledged. The company describes it as “the largest high-quality sapphire wafer ready for production of LEDs.”

With 6” still in roll-out with assumed yield challenges, I’m not sure anyone was taking 12” seriously in January. But the more believable 8” step is just the sort of killer move that Samsung could be expected to make in LEDs.

Meanwhile, Lattice Power Corp. announced that together with ShineOn Inc., they have demonstrated the world's first high-brightness LED product based on GaN-on-Si technology. Aimed at general lighting applications, Lattice claims the product is suitable for indoor lighting, incandescent replacement bulb, flashlight and even direct-lit LCD backlighting applications. Both Philips and Bridgelux have announced R&D developments for GaN on Si, but not commercial product.

Substrate innovation and size advancements will be a critical competitive factor in LEDs for several years. These and other announcements promise a lot of smoke and fire for the foreseeable future.