The application of GaN-on-Si to create larger epitaxial wafers is predicted to play a role in reducing the cost of microLED displays.
With its latest results, Allos is claiming enhanced wavelength uniformity consistently standard deviation of below 1nm on 200mm-diameter wafers.
"At the same time we achieve all other production requirements like bow of less than 40 micron and SEMI-standard thickness of 725 micron. These parameters are very important when bonding CMOS wafers to LED epiwafers," added by Alexander Loesing, one of the co-founders of Allos.
Allos was founded by former Azzurro employees after the closure of Azzurro Semiconductors AG in 2014. Allos bought all the intangible assets of Azzurro, including the technology, know-how and patents in an auction process.
Fellow co-founder Atsushi Nishikawa, CTO of Allos, said: "Already our predecessor company Azzurro had been first in the market with commercial 150mm and later 200mm GaN-on-Si epiwafer products. Making 300mm was the next natural challenge. When the first reactor designed for such large wafers, the Veeco ImPulse, became available we proceeded to tackle the challenge."
Scaling up from 100 mm diameter – the typical wafer dimension for GaN-on-sapphire – has a bigger business impact for micro LEDs than in other parts of the LED industry, Allos said. Beside lower cost per area when using larger diameters, the jump to 200 mm and 300 mm GaN-on-Si for microLED production, enables the usage of CMOS facilities that have a much lower cost and additionally higher production accuracy than conventional LED lines.
Summarizing the advantages of 300mm diameter wafers, Loesing said: "For microLED displays the better area utilization of larger wafer sizes can easily account for 40 percent cost advantage from 300mm epiwafers for this step alone. Together with the other cost advantages and the production benefits offered by CMOS lines this results in leading industry players evaluating microLED displays based on 300 mm GaN-on-Si."
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