F. Vasquez

University of Connecticut

  • 4B.4 – Double-Side Diamond Cooling of GaN HEMTs and Progress Towards Further Reductions in Junction-to-Package Thermal Resistance

    James Spencer Lundh, National Research Council Postdoctoral Fellow, Residing at NRL
    F. Vasquez, University of Connecticut
    A. J. Cruz Arzon, University of Connecticut
    T.I. Feygelson, U.S. Naval Research Laboratory, Washington DC
    Alan Jacobs, U.S. Naval Research Laboratory
    Andrew Koehler, U. S. Naval Research Laboratory
    B.B. Pate, U.S. Naval Research Laboratory
    Karl D. Hobart, U.S. Naval Research Laboratory
    Travis J. Anderson, U.S. Naval Research Laboratory
    M.A. Mastro, U.S. Naval Research Laboratory
    G. Pavlidis, University of Connecticut
    D. Francis
    M.J. Tadjer, U.S. Naval Research Laboratory

    4B.4 Final.2025

    Abstract
    Herein, we demonstrate top, bottom, and double-side thermal management strategies for gallium nitride (GaN) high electron mobility transistors (HEMTs). The cooling technologies investigated include GaN/SiC (reference), GaN/diamond (bottom-side), diamond/GaN/SiC (top-side), and diamond/GaN/diamond (double-side). We review processing methods to realize these device structures as well as the intricacies of the fabrication process. From DC output characteristics, the diamond/GaN/diamond HEMTs demonstrate over 0.6 A/mm at VGS = 2 V. From a thermal perspective, the double-side diamond cooling approach enabled operation at DC power densities of ~30 W/mm with a peak temperature rise of ~50 K at the drain-side edge of the gate electrode. Finally, we demonstrate our initial efforts towards diamond encasement of AlGaN/GaN epilayers to further reduce device-level thermal resistance.