LONDON – As promised Plessey Semiconductor Ltd. (Plymouth, England) has started producing light emitting diodes (LEDs) on gallium nitride (GaN) on silicon wafers. The company claimed it is the first to offer LEDs manufactured on 6-inch diameter wafers using GaN-on-silicon anywhere in the world.
The product on offer – the PLW111010 – is an entry-level product with a light output of just 2 lumens intended for indicator lamps and back-lighting applications, but Plessey has a road-map of introductions planned for the rest of 2013. The company plans to be offering LEDs for solid-state light bulb applications before the end of 2013.
The initial product comes in a two-pin PLCC2 package that measures 3.5-mm by 2.8-mm. Plessey is using its wafer fab at its Plymouth, England facility and reports yields of greater than 95 percent and fast processing times provide a significant cost advantage over sapphire and silicon carbide based solutions for LEDs of similar quality.
At present the company has a single reactor for laying down the GaN on silicon wafers and production is limited to about 500 wafers per month. While these numbers may appear low each six-inch wafer can produce about 14,000 die. The company has plans to run approximately 10 reactors in future.
The technology to carefully manage strain in layers of GaN and aluminum and indium originates at Cambridge University. Plessey announced it had acquired CamGaN, a company formed to commercialize the technology, in February 2012.
However, one concern could be that other manufacturers will be able to outflank Plessey by manufacturing GaN-on-silicon LEDs on yet larger, and therefore more economical, 200-mm diameter wafers.
"We have an 8-inch facility here [in Plymouth] and this is transition we could make," said Barry Dennington, chief operating officer of Plessey. eith Strickland, Innovations and Technology Director at Plessey, commented: "The base technology does scale. We could go to 8-inch wafers. And the showerhead reactors are upgradeable to 8-inch wafers."
"We will continue to make progress in output efficiency and are on plan to release further improvements in light output throughout this year and into next. The operating and unit costs are on plan and we are seeing a number of routes to enhance our cost advantage over competing technologies," said Dennington, in a statement.
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