James Gillespie

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.

    Download Paper
  • 3.1 Demonstration of X-band T/R MMIC using AFRL AlGaN/GaN MMIC Process

    James Gillespie, Air Force Research Laboratory
    Kelson Chabak, Air Force Research Laboratory
    Antonio Crespo, AFRL
    Robert Fitch, AFRL
    Darren Ferwalt, Cobham Advanced Electronic Systems
    David Frey, Cobham Advanced Electronic Systems
    Jeremy Gassmann, Cobham Advanced Electronic Systems
    Mark Walker, Cobham Advanced Electronic Solutions
    Ryan Gilbert, Wyle Laboratories
    Dennis Walker Jr, Air Force Research Laboatory, Sensors Directorate
    Glen Via, AFRL
    A.J. Green
    K.D. Leedy
    R.K. Mongia
    B.S. Poling
    K.A. Sutherlin
    S.E. Tetlak
    J.P. Theimer
    G.H. Jessen
    Download Paper