HexaTech Inc of Morrisville, NC, USA has received a $2.2m award from the US Department of Energy (DOE) Advanced Research Projects Agency – Energy (ARPA-E) to enable the development of “new power semiconductor technology for the modernization of our electrical power grid”.
HexaTech was spun off from the Department of Materials Science of North Carolina State University in 2001 with a transfer of technology — developed by the firm’s co-founders Dr Zlatko Sitar (president & chief technology officer) and Dr Raoul Schlesser (VP development) — to produce single-crystalline bulk aluminium nitride (AlN) substrates for both electronic and optoelectronic devices. Subsequently, in late 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.
In 2007, HexaTech won a $2m Advanced Technology Program (ATP) grant from the US Commerce Department’s National Institute of Science and Technology (NIST) as part of a $3.28m, three-year project (starting in November) to develop high-effiency deep ultraviolet LEDs for use as a high-energy UV light source to kill micro-organisms in drinking and waste water. Since then, HexaTech raised $300,000 in debt financing in January 2010, followed by a further $3.1m in a round that closed this July. Including a further $500,000 in debt financing in August, HexaTech has raised more than $17m in total since the firm was founded.
HexaTech’s AlN technology has now been identified by the Department of Energy as a “transformational, breakthrough technology with significant technical promise”.
Using very low-dislocation-density single-crystal AlN substrates, HexaTech aims to develop novel doping schemes and contact metals for AlN/AlGaN with high Al content. “The development will enable a significant step toward producing 20kV AlN-based Schottky diodes (SBD, JBSD) and transistors (JFET, MOSFET),” says director of engineering Dr Baxter Moody. “The ARPA-E contract has opened the door for the material development and research to demonstrate AlN high-voltage, high-efficiency power conversion capability,” he adds. For power systems and grid-scale power conversion applications, high-efficiency AlN-based power devices will offer a significant reduction in size, weight, and cooling, reckons HexaTech.
Power semiconductor devices at this level are not currently available on the market, the firm says. Experimental devices based on silicon carbide (SiC) technology are being developed. But, compared to SiC technology, AlN should enable power electronics with a 10x improvement in performance. Based on AlN’s wide-bandgap material properties, the critical field is 6x larger, the on-resistance will be lower, and the resulting power device area will be smaller for a comparable power level, the firm concludes.
