Dennis Walker

Air Force Research Laboratory
  • Dispersion Characteristics of ScAlN and ScAlGaN HEMTs by Pulsed I-V Measurements

    Kelson Chabak, Air Force Research Laboratory
    Cathy Lee, Qorvo Inc.
    Yu Cao, Raytheon IDS Microelectronics, Novati Technologies, Inc. IQE
    Andy Xie, Qorvo
    Edward Beam, QORVO
    Kyle Liddy, KBR
    Antonio Crespo, AFRL
    Dennis Walker, Air Force Research Laboratory
    Robert Fitch, AFRL
    James Gillespie, Air Force Research Laboratory
    Andrew Green, Air Force Research Laboratory

    We report the dispersion characteristics of ScAlN/GaN high-electron-mobility transistors (HEMTs) with various epitaxial designs. Devices were fabricated on both ternary (ScAlN) and quaternary (ScAlGaN) materials. The effects of a GaN capping layer was also investigated. We report similar DC and RF performance for all wafers, but significantly worse dispersion which occurs on the quaternary samples. We observe a total gate and drain lag for the ScAlN wafer to be 49% while the ScAlGaN with and without the GaN cap had 10 and 12% dispersion, respectively.

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  • 14.4 Device Development of Gallium Oxide MOSFETs Grown by MOVPE on Native Substrates for High-Voltage Applications

    Neil Moser, George Mason University
    Kelson Chabak, Air Force Research Laboratory
    Andrew Green, Air Force Research Laboratory
    Dennis Walker, Air Force Research Laboratory
    Stephen Tetlak, AFRL
    Eric Heller, AFRL
    Antonio Crespo, AFRL
    Robert Fitch, AFRL
    Jonathan McCandless, AFRL
    Kevin Leedy, AFRL
    Michele Baldini, Leibniz-Institut für Kristallzüchtung
    Guenter Wagner, Leibniz-Institut für Kristallzüchtung
    Glen Via, AFRL
    John Blevins, Air Force Research Laboratory
    Gregg Jessen, AFRL
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