627538 news 1571055849 1571056147 UMI researchers, led by Prof. Abdallah Ougazzaden, have demonstraded an innovative technology that can eliminate a costly step in the packaging of III-N optoelectronic devices.  III-N devices typically require dicing of the epitaxial materials to separate individual devices from each other. In this new technique, a pattern of SiO2 was fabricated on the sapphire substrate. Then h-BN was grown on the wafer.  The beauty of this this technique is the h-BN forms atomically flat layers on the exposed sapphire surface, while the h-BN on the SiO2 patterns was disordered.  Then GaN-based device epitaxy was performed.  Surprisingly, the h-BN on SiO2 did not permit subsequent growth of GaN-based materials, while the h-BN on Sapphire did permit growth of GaN-based devices.  So the GaN based devices were physically separated from each other, and they could be easily removed from the substrate because h-BN is not chemically bonded to the GaN-based device. This technology has the possibility of eliminating dicing steps during III-N optoelectronic packaging by permitting convenient pick-and-place of individual devices on other substrates.

]]> 2019-10-14T00:00:00-04:00 This new technique uses a combination of van der Waals epitaxy of h-BN and selective area growth techniques that results in individual GaN-based devices such as LEDs, HEMT transistors, or solar cells that can be easily removed from the sapphire substrate and placed on other supports. Given that GaN and Sapphire are some of the hardest and strongest materials around, this is quite the trick!

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