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10 October 2007


HexaTech awarded $2m ATP grant for high-efficiency UV-LEDs

HexaTech Inc of Morrisville, NC, USA, which manufactures single-crystal aluminum nitride substrates, has been granted $2m for a three-year project (starting in November) to develop high-effiency deep ultraviolet LEDs that can be used as a high-energy UV light source to kill microorganisms in drinking and waste water. Such UV-LEDs could be used by water treatment companies as a replacement for existing mercury-based UV tubes that would be both more environmentally friendly and also last 5-10 times longer. However, although several research groups have demonstrated LEDs with deep UV wavelengths as short as 210nm, so far they convert less than 1% of the applied electrical energy into light.

The funding comes as part of the final set of Advanced Technology Program (ATP) awards of the US Commerce Department’s National Institute of Science and Technology (NIST). Together with projected industry cost-share of almost $1.3m, total project funding should be $3.28m. Together with projected industry cost-share of almost $1.2m, total project funding should be $3.2m.

HexaTech was spun off from the Department of Materials Science of North Carolina State University in 2001 with a transfer of technology developed by co-founders Dr Zlatko Sitar (president and chief technology officer) and Dr Raoul Schlesser (VP development). Subsequently, in November 2005, the firm raised $8.9m in a Series A round of financing led by Intersouth Partners of Durham, NC and joined by H.I.G. Ventures, Sevin Rosen Funds and NC IDEA.

HexaTech says that its proprietary technology combines the benefits of physical vapor transport (PVT) growth and of seeded growth for the reproducible production of single-crystal AlN boules. Seeded growth enables the fabrication of AlN boules of pre-defined crystallographic orientation. AlN wafers fabricated from the crystals are of well-defined orientation and of high, reproducible crystal quality, the firm says.

In addition, more recently HexaTech has demonstrated a polarity-controlled device layer deposition process that is compatible with industry-standard MOCVD growth equipment. Control over the polarity opens up processing routes that can lead to novel device concepts that have previously been inaccessible, says the firm. It adds that it aims to produce efficient deep-UV LEDs by taking advantage of such processes to grow aluminum gallium nitride (AlGaN) layers on AlN substrates. HexaTech’s CEO Jim LeMunyon told Semiconductor Today that the targeted emission wavelength is 254nm, which is known to interact with DNA in a way that stops water-borne organisms from reproducing.

Regarding commercial prospects for the technology, HexaTech reckons that deep-UV LEDs can address a $78m market for the initial replacement of UV tubes at water treatment companies, followed by a recurring market of $15.6m per year (beginning five years after the first UV-LED systems are installed).

See related item:

Crystal IS wins $2m ATP award for deep UV LEDs

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