Toshiba plans silicon-based LED production; Azzurro installs Veeco MOCVD
Toshiba has announced that it will begin mass producing silicon-based white LEDs in October 2012 on a 200-mm line at Kaga Toshiba Electronics Co. Azurro Semiconductors, another silicon-based LED maker, has installed a Veeco Instruments metal organic chemical vapor deposition (MOCVD) system to build LEDs and other power semiconductors.
Toshiba and Bridgelux
Toshiba will manufacture phosphor-converted white LEDs using gallium-nitride-on-silicon (GaN-on-Si) technology developed by partner Bridgelux. By using a silicon wafer rather than the more typical sapphire wafer, Toshiba can take advantage of automated production tools for the back end of the LED manufacturing process that have been long proven in the broad IC industry, and in turn reduce component costs.
The fact that Toshiba will focus on 200-mm (8-in) wafers is also significant. Larger wafers mean more LED chips per wafer and potentially lower costs, although to date no one has fully proven such a manufacturing line with acceptable yields. Most sapphire-based LED production has been done on 2- and 4-in wafers although the industry has rapidly moved to 6-in wafers over the past year.
The production line will depend on "the combination of Bridgelux’s crystal growth and LED chip structure and Toshiba’s advanced silicon process and manufacturing technology," according to Toshiba. The company said it had manufactured a prototype chip with maximum radiometric output of 614 mW, and presumably judges that performance suitable for production components.
Bridgelux announced last year that it had produced GaN-on-Si LEDs in the lab with an efficacy of 150 lm/W in cool white. The company said it was working on making the process and recipe stable and transferrable.
In May of this year, Bridgelux announced that Toshiba had invested an unspecified amount in Bridgelux. At that time, Bridgelux had first mentioned the 614-mW performance level achieved with a drive current of 350 mW and a forward voltage of 3.1V.
Azzurro taps Veeco
Last week we covered an announcement of funding that Azzurro Semiconductors received to further develop its GaN-on-Si technology and extend it to 200-mm wafers, and subsequently Veeco Instruments announced that Azzurro has installed a Veeco TurboDisc K465i MOCVD system that's used to grow the epitaxial layer on wafers for LEDs and other power semiconductors.
"Our technology provides high-quality, crack-free GaN layers on 150-mm standard silicon wafers with very good crystal quality and extremely low bow values. We chose Veeco's K465i to produce these high efficiency GaN-on-Si stacks because of its performance, process stability, and high throughput," said Markus Sickmoller, vice president of operations at Azzurro. "We believe our GaN-on-Si technology will trigger a new wave of highly efficient and cost-optimized components for the LED and power semiconductor industry."
"The power electronics device market is forecasted by Yole Developpement to be $25B by 2015, and GaN has the ability to make devices with higher efficiency and switching speed than traditional Si devices. Further, LEDs made with GaN-on-Si technology will enable lower LED costs," said Jeff Hawthorne, Veeco's senior vice president of MOCVD. "We anticipate that the demand for MOCVD tools for these GaN-on-Si applications will grow as technology moves from R&D into production. Veeco's K465i systems offer key advantages for GaN-on-Si production, including low particle count and excellent yields, and we're looking forward to continuing to support Azzurro's growing GaN-on-Si business."
