News Article
Kyma executive gives invited talk for LED manufacturers
The talk outlined the best way to grow aluminium nitride on patterned sapphire substrate (PSS) for the fabrication of high quality gallium nitride LEDs.
Kyma Technologies, a supplier of crystalline AlN and GaN and related products and services, participated in an invitation only workshop held in Taipei, Taiwan last week.
The workshop was focused on recent developments related to PSS technology for nitride semiconductor LED manufacturing.
At the workshop, Edward Preble, Kyma’s Chief Technology Officer and Vice President of Business Development, gave an invited talk entitled “Plasma Vapour Deposition of Nano-Columnar (PVDNC) AlN on PSS for fabrication of high quality GaN LEDs.”
In his talk he discussed the use of the PVDNC crystal growth process to produce nano-columnar structures on top of the micro-structured features already present on a PSS substrate, and the observed benefits by LED manufacturers.
“I am thankful to the organisers, especially Natsuko Aota-san and Hideo Aida-san at Namiki Precision Jewel Company, for inviting me to this meeting,” commented Preble. “I really enjoyed the open exchange of ideas on how to better capitalise on the many opportunities that are available to enhance the properties of sapphire substrates in support of better LED performance and reduced LED manufacturing costs.”
PSS substrates have become increasingly important in GaN LED manufacturing. Only a few years ago most GaN LEDs were made using flat sapphire; today up to 30% utilise PSS and the trend is expected to continue such that PSS may be more important than flat sapphire by 2015.
There are several different methods, including both wet and dry etching, for making PSS, and the detailed microstructures being used and investigated are manifold. LED manufacturers and research scientists report several different benefits and those benefits seem to vary from group to group. Reported benefits include a lower defect density in the GaN buffer, higher thermal conductivity of the device heterostructures, and greater light extraction efficiency.
Kyma’s PVDNC process has been used to deposit high quality AlN on both flat and PSS sapphire, as well as on flat silicon, as a nucleation layer for improved GaN buffer layers . Kyma has not tried PVDNC AlN on patterned silicon and encourages interested parties to contact the company for discussion.
Kyma says that the market for nitride semiconductor devices is estimated to be $9B in 2011 and is expected to reach $90B over the long term, including $60B in visible lighting applications and $30B in power electronics applications.
