8 June 2011

Kyma updates progress in crystalline AlGaN and AlN materials development

Kyma Technologies Inc of Raleigh, NC, USA, which provides crystalline gallium nitride (GaN) and aluminum nitride (AlN) materials and related products and services, has provided an update on its progress in crystalline AlGaN and AlN materials development and its desire to collaborate with bulk AlN developers interested in improving the optical transparency of their materials.

Kyma says that it has more than a decade of experience in the fabrication of AlN templates (thin films of crystalline AlN deposited on sapphire, silicon, or silicon carbide substrates) using its patented and proprietary III-N Plasma Vapor Deposition of NanoColumns (PVDNC) technology. These products are gaining acceptance with customers engaged in blue and green light-emitting diode (LED) manufacturing, the firm adds. The nanocolumnar nature of PVDNC AlN templates presents what is claimed to be an excellent surface for nucleating GaN buffer layers, which can then be followed by a high-quality GaN LED device structure.

Kyma recently began extending its process capabilities to develop materials that are designed to support high-Al-content device layer structures, which are of interest for ultraviolet (UV) and high-temperature and high-power electronics applications.

“While our PVDNC AlN templates are excellent substrates for manufacturing GaN-rich devices such as blue and green LEDs and AlGaN/GaN field-effect transistors (FETs), we are also employing other processes to develop materials that are specifically tailored to support the manufacturing of AlN-rich devices such as mid-UV LEDs for germicidal irradiation and AlN/AlGaN FETs for temperature-insensitive high-power electronics applications,” says president & CEO Dr Keith Evans.

Towards these goals, Kyma is exploring and has made significant progress in the growth of crystalline AlN and AlGaN materials using high-growth-rate hydride vapor phase epitaxy (HVPE).

By adding a novel Al source to its HVPE tools, Kyma is now able to grow crystalline AlN and a broad range of AlGaN compositions. Also, just like GaN HVPE, the structural quality of the HVPE-grown AlN and AlGaN crystals are influenced by the seed crystal on which they are grown.

Kyma has already demonstrated the ability to deposit crystalline AlN by HVPE on a range of starting seed materials, including on AlN structures that were produced by other techniques.

“Our AlN HVPE process appears to have many of the traits of our GaN HVPE process,” says Ed Preble, chief technology officer & VP business development. “We are able to rapidly replicate the quality of the underlying seed and, in certain cases, then improve its quality as we continue to grow the crystal,” he adds.

“Additionally, optical transmission measurements show that our HVPE-grown AlN materials have high transparency in the 200–400nm spectral region, an important feature for UV LED applications, and a noted advantage over some competing AlN crystal growth approaches,” Preble claims.

Kyma is currently seeking partnerships with bulk AlN materials developers who are interested in the possibility of improving the optical properties of their materials.

Tags: Kyma AlGaN GaN AlN HVPE

Visit: www.kymatech.com