November 30, 2004, Silver Spring, MD--Technologies and Devices International, Inc. (TDI), a privately held Maryland corporation, is presenting its new product prototype, aluminum gallium nitride (AlGaN)-on-sapphire templates, at the 2004 Material Research Society (MRS) Fall Meeting and Exhibits (Boston, MA; November 30 through December 2, 2004). Novel AlGaN-on-sapphire materials are transparent in the ultraviolet (UV) and are targeting substrate applications for high-power GaN-based UV light-emitting diodes (LEDs), including deep-UV emitters operating at wavelengths as short as 250 nm.
Gallium nitride-based light emitting devices operating in the UV and deep-UV spectral regions are the subject of intense development for environmental, medical, biotechnical, and military applications. Tremendous potential for GaN-based LEDs also exists in solid-state lighting applications. The GaN LED market is one of the fastest-growing technical markets worldwide, and is projected by Strategies Unlimited (Mountain View, CA) to exceed $4 billion in 2007.
One of the major technical hurdles for the development and commercialization of UV LEDs is the absence of low-defect UV-transparent substrate materials having crystal parameters that are close to those of AlGaN light-emitting devices. Novel UV-transparent AlGaN-on-sapphire materials fabricated by TDI's patented hydride vapor-phase epitaxial (HVPE) process provide a potential solution for the problem.
The higher the proportion of AlN in an AlGaN semiconductor light emitter, the shorter the wavelength that is emitted--a result of the large bandgap of AlN. As the proportion of AlN rises, however, the fabrication of high-quality devices becomes more difficult.
"Deposition of high-quality UV transparent AlGaN films is very challenging and we are pleased with recent results on the HVPE growth of AlGaN materials, a process that has no analogues," says Vladimir Dmitriev, CEO and President of TDI. "Now we can produce AlGaN films with AlN composition from 5% to 75%, covering substrate needs for UV optoelectronic devices operating from 250 to 350 nm. Initial test of novel AlGaN templates by TDI customers gave very promising results and the company has received trial orders for these materials. We plan to continue material development and start pilot production of 2-in. UV-transparent low-defect AlGaN templates in 2005."
Dmitriev notes that the Defense Advanced Research Project Agency (DARPA), Microsystems Technology Office and the U.S. Department of Defense provided support for this project.