Kyma Technologies, Inc., a leading supplier of advanced materials solutions that promote safety and energy efficiency, is pleased to announce three recent advances in homoepitaxial growth technology for manufacturing crystalline GaN and AlN materials.

Crystalline gallium nitride (GaN) and aluminum nitride (AlN) are wide bandgap semiconductor materials which represent important ingredients in future energy efficient lighting and electric power management, the combined market for which is expected to someday reach $100B at the semiconductor chip level. For this to happen, scientists and engineers worldwide are researching ways to advance the technology of GaN and AlN crystal growth to reduce the size and cost of the underlying devices and to support increased device performance, electrical efficiency and reliability.

A key objective in such research is to realize the ability to produce better homoepitaxial GaN and AlN materials more quickly and at lower cost. Kyma's high growth rate hydride vapor phase epitaxy (HVPE) technology can support growth rates of up to 500 microns/hour, translating to a hundred-fold speed advantage relative to metalorganic chemical vapor deposition (MOCVD). Additional benefits of HVPE over MOCVD are lower cost starting materials and higher chemical purity crystals. And since HVPE is a vapor phase process, it is relatively easy to incorporate intentional dopants and adjust growth rates and V/III ratios.

Kyma is leveraging the benefits of its HVPE technology in three areas of homoepitaxy:

High quality GaN homoepitaxy for boule process development: Kyma has demonstrated high quality homoepitaxial HVPE growth of GaN on low-defect density GaN substrates with HVPE layer thicknesses up to 100 microns, an important step towards realization of a low defect density GaN boule growth process. This work is supported by US DOE's Advanced Research Projects Agency (ARPA-E) under their SWITCHES program and has the potential to enable improved energy efficiency in next generation lighting and power electronics.

Equivalent high growth rate homoepitaxy of Ga-face and N-face GaN for Non Linear Optics (NLO): Kyma has also successfully tailored its GaN HVPE process to realize state-of-the-art high rate growth of periodically oriented crystalline GaN layers for advanced non-linear optics (NLO) applications. The periodic orientation of the crystal refers to the realization of alternating stripes of Ga-face and N-face c-plane GaN which creates an alternating refractive index to support quasi-phase matching which when done in the GaN materials system is predicted to lead to improved NLO response compared to incumbent technologies. Kyma has met specific crystal growth challenges in achieving equal growth rates for the alternating polarity crystalline GaN layers while simultaneously supporting high growth rates and thicknesses beyond 500 microns. This work is supported by and performed in collaboration with Naval Research Laboratory (NRL) and has resulted in several publications and the recent demonstration of the predicted NLO behavior. This work has the potential to impact current and future high performance laser systems for a number of commercial and defense applications.

High transparency AlN homoepitaxy for UV LEDs: Kyma has demonstrated successful high-quality homoepitaxial HVPE growth of AlN on low-defect density AlN substrates with HVPE layer thicknesses that support improved ultraviolet (UV) LED manufacturing. Currently available high-quality AlN substrates are too absorbing at the intended LED output wavelengths and must be nearly completely removed for efficient UV LED operation. The HVPE AlN overlayer simplifies the AlN substrate removal process and supports high-efficiency device operation while keeping the HVPE AlN intact for a more robust device fabrication process. This work is supported by one of Kyma's commercial partners and has the potential to support a new generation of water and air purification technologies. Also, this effort is leveragable towards using HVPE to grow the entire (Al,Ga)N epitaxial device layer structure for next generation AlN-based power electronics.

Historically Kyma has focused on heteroepitaxial approaches, usually beginning with sapphire, for producing various GaN, AlN, and GaN template products and to quick start their own bulk GaN growth efforts. Essentially all of Kyma's current III-N materials products are fabricated as such. But now that low defect density AlN and GaN starting materials are becoming available, Kyma's high rate HVPE process can be leveraged to create an entire new generation of advanced materials.

"We are thankful for the support of ARPA-E, NRL, and our commercial partner," stated Keith Evans, president and CEO. "These advances in high rate AlN and GaN homoepitaxial growth technology represent important steps for us as they open up a number of exciting growth directions for the company."

For more information about Kyma's products and services, contact the company at sales@kymatech.com.

About Kyma Technologies

Kyma’s mission is to provide advanced materials solutions that promote safety and energy efficiency. Kyma’s products include a diverse portfolio of crystalline nitride semiconductor materials, crystal growth and fabrication equipment, and power switching electronics. Additionally, the company is developing a novel electromagnetic field sensor technology.

For more information about Kyma Technologies, visit www.kymatech.com, e-mail info@kymatech.com, or call the company directly at 919.789.8880.

Kyma is a registered trademark of Kyma Technologies, Inc.