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September 3, 2004
For Immediate Release

HRL laboratories announces unprecendented GaN IC capabilities

LOS ANGELES, September 3, 2004-- HRL Laboratories, LLC today announced two unprecedented achievements in gallium nitride/aluminum gallium nitride (GaN/AlGaN) heterostructure field effect transistor (HFET)-based monolithic microwave integrated circuits (MMICs). The first achievement is the design, fabrication, and demonstration of a 33 GHz (Ka-band) power amplifier MMIC with output power levels up to 2.8 W and power added efficiency of 27%. The second achievement is the demonstration of a robust and linear, broadband (3-18 GHz) low noise amplifier (LNA) MMIC with 20 dB of gain and a minimum noise figure of 2.4 dB.

GaN HFETs offer higher output power densities, higher breakdown voltage, and better survivability than gallium arsenide (GaAs) transistors at microwave and millimeter-wave frequencies, motivating development of MMICs for applications requiring high power density, high linearity, and robust operation. The Ka-band accomplishment, reported here, also points to significant improvements available at X-band for power amplifier efficiencies beyond the 43% reported by HRL four years ago in its 20-W amplifier demonstration. GaN also offers the potential for very high temperature operation in severe environments.

HRL's GaN-based MMIC process uses epitaxial GaN and AlGaN layers deposited by molecular beam epitaxy on SiC substrates, which possess high thermal conductivity for dissipation of unwanted heat. AlGaN/GaN HFETs are the basic transistor building blocks, with a maximum frequency of oscillation (fmax) up to 140 GHz. HRL has developed two different MMIC process architectures (individual-slot-via microstrip and coplanar waveguide), enabling optimization of performance and cost in a given application. These MMICs complement HRL's previously reported GaN-based digital ICs that integrated over 200 transistors and were tested at clock frequencies above 40 MHz for full functionality up to 260oC.

The digital IC process uses sapphire substrates for substantially reduced cost. Both types of ICs were fabricated on 3-inch-diameter wafers; a 100-mm substrate process has recently been developed at HRL enabling a 70% increase in fabricated devices per wafer. HRL has already successfully demonstrated GaN on four-inch substrates, and is positioned to meet increased market demand as insertion opportunities for GaN components grow.

HRL Laboratories, LLC develops and produces GaN/AlGaN HFET integrated circuits for such RF applications as power amplifiers and low noise amplifiers and for robust high temperature control electronics for its LLC Member Companies (Boeing, General Motors, and Raytheon), for the US Government, and for commercial customers.

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