WASHINGTON – The gallium nitride (GaN) wafers from the US Naval Research Laboratory, also known as large-area substrates, can turn GaN into a potential displacement technology for silicon semiconductors in microelectronics, especially in power electronics.
A typical substrate in microelectronics is a thin, crystalline semiconductor wafer. A constructed substrate is a composite structure of polycrystalline and crystalline layers that are optimized for good thermal expansion and crystalline conformance to GaN. The excellent thermal expansion matching enables thick GaN epitaxial layers that have made 1200 volts and more GaN power switches possible.
Karl Hobart and Francis “Fritz” Kub, both electrical engineers and heads of the department for high-power devices and the department for high-power electronics at the US Naval Research Laboratory, are the leading inventors of GaN-engineered substrates.
“The unique thing about GaN material is that it is a wide band gap semiconductor that can support higher electric fields,” said Hobart. “It’s also a useful light emitter and very fast switch for high frequency applications, but we’re more interested in high voltage devices with a high electric field.”
GaN operates at much higher voltages, frequencies, and temperatures than traditional semiconductor materials like silicon, enabling more efficient, smaller, lighter, faster, and less expensive end products.
The large diameter of the substrate wafer developed by GaN enables the production of more stable GaN devices per wafer, which leads to a more cost-effective production.
The NRL Office of Technology Transfer, led by Amanda Horansky-McKinney and her team, promoted the development and commercialization of this particular GaN technology. You were awarded the Federal Laboratory Consortium’s Excellence in Technology Transfer Award 2021 in April.
Hobart and Kub had the basic research idea for these GaN substrates in the early 2000s.
“At that time we realized that the existing GaN substrate technology was neither scalable nor affordable. We envisioned a new ‘engineered’ substrate technology that could achieve large diameters compatible with advanced semiconductor manufacturing foundries, “said Hobart.
Through the efforts of the NRL’s Technology Transfer Bureau, GaN substrates have found their way through a number of companies, each with different points of view on commercialization.
“The ultimate recipient of the transferred technology is QROMIS, Inc. of Silicon Valley,” said Horansky-McKinney. “QROMIS is well positioned to do exactly what we want our licensees to do – investing and building an intellectual property base that will support a competitive market position for their products using NRL technology as a foundation.”
Cem Basceri, CEO and President of QROMIS, said working with NRL was an extremely positive experience and the partnership and teamwork exceeded his expectations.
“In terms of the quality of work, especially NRL’s Tech Transfer, Ms. Horansky-McKinney did a great job and helped make everything run so smoothly,” said Basceri. “The collaboration with the scientists and engineers at the NRL is excellent as they have very unique and innovative ideas that can be turned into commercial solutions.”
The technology transfer partnership was initiated in 2009 when six patents formed the basis of NRL’s innovation and were then licensed to a small company called Amberwave Systems Corporation. The company was then taken over by Micron Technology, which invested in the further development of the GaN substrate concept under the NRL license.
“It was encouraging that our innovation was recognized by the industry as the future of GaN technology and was dedicated to advancing towards commercialization,” said Kub. “We thought our technology was a good idea, but they must have thought it was a great idea to make such a large investment in technology.”
Historically, GaN wafers have had shortcomings such as thermal expansion mismatch between silicon. However, NRL’s research experts and their trading partners were able to solve the problem by developing a thin, inexpensive wafer made from polycrystalline aluminum nitride that has good thermal expansion of gallium nitride. In addition, a thin layer of single crystal silicon was added for GaN nucleation and to avoid mechanical problems. You are now able to manufacture a wafer with optimal component performance and affordability.
QROMIS used these solutions to launch its commercial products called QST® substrates and GaN-on-QST® epi wafers.
Hobart and Kub’s advice to other defense researchers working to take their fundamental science and technology endeavors from inception to commercialization: Work closely with a company interested in the technology.
“The industry-NRL partnerships have resulted in the successful development and transfer of technology that will greatly benefit the Navy and Marine Corps,” said Horansky-McKinney.
The U.S. Naval Research Laboratory’s technology transfer office facilitates and promotes the NRL’s innovative technologies in products and services to benefit the public and the nation’s soldiers and soldiers. Learn how NRL technologies are commercialized or how companies can benefit from working with some of the world’s most respected scientists at https: /:
Via the U.S. Naval Research Laboratory
NRL is a scientific and engineering command dedicated to research that drives innovative advances for the US Navy and Marine Corps from the ocean floor to space and information. NRL is based in Washington, DC with main offices in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 2,500 civil scientists, engineers, and support staff.
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