Gallium nitride on silicon (GaN-on-Si)-based LEDs have been fabricated using high‐brightness LED structures of Epistar Corp of Taipei, Taiwan and the patented technology for 150mm GaN-on-Si substrates of Azzurro Semiconductors AG of Dresden, Germany, which makes gallium nitride (GaN) epitaxial wafers based on large-area silicon substrates.
Completion of the joint project confirmed the performance that can be reached, says Azzurro. In particular, the two firms are satisfied with the extremely short development time of just 16 weeks for transferring Epistar's existing LED structures (fabricated on sapphire substrates) to the GaN-on-Si material system. The latest milestone takes GaN-on-Si a step further towards implementation in mass production, reckons Azzurro.
While GaN-on-Si is often associated with technological challenges that are difficult to overcome, the use of templates with Azzurro's unique strain‐engineering technology enables epitaxy engineers to quickly transfer their LED structures to GaN-on-Si, says the firm. Furthermore, the patented and proprietary buffer stress management enables homogeneity improvements (<4nm wavelength homogeneity) for LED epiwafers, helping to reduce binning and to increase yield, it is claimed.
The joint project has exceeded expectations regarding speed and cost of migration, says Epistar's chairman Lee Biing‐Jye. "The success helps us to utilize GaN-on-Si, which is a game changer for the industry," he adds.
"It proves our business model to offer dedicated development packages and sophisticated engineering support," states Azzurro's CEO Erwin Wolf, referring to the speed of the development. "The technology to enable the LED industry to tap into the advantages of the volume, cost-effectiveness and maturity of silicon foundries is ready with our strain‐engineered templates," he adds.
