PRESS RELEASE

TDI demonstrates novel technology for GaN and
AlGaN quantum wells and superlattices

October 12, 2006... Silver Spring, Maryland, USA Technologies and Devices International, Inc., a privately held Maryland corporation (TDI), today announced another major breakthrough in Gallium Nitride (GaN) compound semiconductor material technology by fabrication of GaN quantum well (QW) structures using novel hydride vapor phase epitaxy (HVPE). GaN is the compound semiconductor material used for the fabrication of blue spectrum (blue, green, ultra violet (UV) and white) light emitting diodes (LEDs), laser diodes (LDs) and high-frequency/high-power transistors. The GaN-based market is projected to reach $5B in 2007 and exceed $7B in 2009.

“TDI engineers and scientists have successfully developed a novel HVPE growth machine and process which allows us to reduce the materials deposition rate for more than two orders of magnitude and control the growth of GaN, AlN, and AlGaN layers to a thickness of about 1 nanometer”, said Vladimir Dmitriev, President and CEO of TDI. “HVPE is TDI’s core technology, which we use to produce a variety of GaN-based epitaxial products. TDI has perfected the growth of very thick GaN layers, which is typical of the HVPE process, along with very thin layers and multi-layer structures, in the same epitaxial process. This proprietary HVPE process opens up a completely new path for the formation of low defect substrate materials and device structures. We at TDI are very thankful to the Department of Energy (DoE) and Defense Advanced Research Project Agency (DARPA) for their continued support for these developments. TDI plans to release epitaxial products based on HVPE grown superlattice structures and quantum wells in early 2007”.

Professor Subhash Mahajan, his student Fanyu Meng and post-doctoral fellow Ranjan Datta at Arizona State University have made material characterizations of GaN single and multiple quantum well structures fabricated at TDI. They comment: “HVPE is well known method to fabricate thick GaN layers. We never expected this technology to produce nanometer thick GaN layers and multi-layer structures. However, our transmission electron microscopy measurements performed on recent TDI’s samples proved that it is achieved”. Professor Michael Reshchikov, Virginia Commonwealth University added: “This is definitely the first HVPE grown AlGaN/GaN structure that clearly shows a quantum well signature in photoluminescent characterization”.

Quantum well structures are the key elements for a variety of modern semiconductor devices including high brightness LEDs and advanced LDs. Multi-layer structures with nanometer-scale layers are important to reduce defects and control strain in GaN-based materials, to improve doping, and to open new device possibilities. TDI will report these results on HVPE grown GaN-based quantum well structures at the International Workshop on Nitride Semiconductors 2006, October 22 - 27, 2006 in Kyoto, Japan. TDI will also feature these recent epitaxial products including MQW epitaxial wafers at the Workshop’s exhibition.

Figure 1. Transmission electron microscopy (ADF-STEM) cross sectional image of test AlGaN/GaN multi quantum well structure grown by novel HVPE method at TDI, Inc. (courtesy of Prof. Subhash Mahajan, Arizona State University). Five GaN layers having thickness of about 2 nm, 3 nm, 4 nm, 8 nm, and 25 nm are sandwiched between AlGaN barrier layers having thickness of 20 nm.

About TDI

The company is a privately owned developer and manufacturer of novel compound semiconductors including GaN, AlN, and InN. TDI has developed a variety of compound semiconductor materials and devices, primarily for applications in short wavelength optoelectronics and RF power electronics. For novel development results and TDI’s product list please visit www.tdii.com

For more information, contact:

TDI, Inc.
12214 Plum Orchard Drive
Silver Spring, MD 20904, USA
Phone: 1 301 572 7834

FAX: 1 301 572 6435

Email: welcome@tdii.com