GaN-on-Silicon

Global digital signage solution provider STRATACACHE is embarking on a project to construct a microLED display production line in Eugene, Oregon. The company aims to start production in this fab at around 2022-2023, with plans to adopt these microLED displays in its own solutions.

The new factory (E4) will be a complete microLED production line, from epiwafer (on 300 mm silicon wafers), through transfer process and to final module assembly. The company plans to produce a wide range of displays, from tablet-sized panels to large-area displays. Some of these displays will be flexible and transparent as the company sees a market demand for such technologies. The yearly capacity of the E4 is expected to start at a 1 million square meters per year.

GaN-on-Si IP developer ALLOS Semiconductors announced it is collaborating with with Prof. Ohkawa and his team at King Abdullah University of Science and Technology (KAUST) to develop high efficiency nitride-based red LEDs on large diameter silicon substrates.

Prof. Ohkawa and team have developed an indium gallium nitride (InGaN)- based red LED stack with low forward voltage of less than 2.5 V and high efficiency by using local strain compensation and a modified MOCVD reactor design. ALLOS and the KAUST team will combine their unique technologies to handle strain and optimize crystal growth conditions for GaN-on-Si and red LEDs. To this end, the KAUST team will grow its red LED stack on top of ALLOS’ GaN-on-Si-buffer layers, which will be fine-tuned during the collaboration to optimize the performance of KAUST’s red LED stack.

German-based GaN-on-Si developer ALLOS has applied its technology to large 300 mm epiwafers. ALLOS says that scaling up to 300 mm wafers enables higher production efficiencies and thus lower costs. ALLOS estimates that the higher area utilization alone accounts for a cost advantage of 40% compared to standard LED wafers. Standard 300 mm silicon line tools also offer higher production uniformity and yield.

ALLOS demonstrated the 300 mm scale-up using a reactor made by Veeco who announced selling the first 300 mm GaN reactor to a leading-edge semiconductor fab just some month ago and also showed 300 mm wafer data at CES. ALLOS reports a wavelength uniformity of consistently below 1 nm and "all other production requirements like bow of < 40 µm and SEMI-standard thickness of 725 µm". ALLOS says scaling to 300 mm shows how robust its GaN-On-Si technology is.