H. Czap

Fraunhofer Institute

  • A new approach for GaN normally-off power transistors: Lateral recess for positive threshold voltage shift

    P. Waltereit, Fraunhofer Institute
    A. Leuther, Fraunhofer Institute
    J. Rüster, Fraunhofer Institute
    H. Czap, Fraunhofer Institute
    R. Iannucci, Fraunhofer Institute
    S. Müller, Fraunhofer Institute
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  • 2A.3 – 1700 V Breakdown Monolithic Bidirectional GaN/AlGaN MISHEMTs with a Thin Buffer Grown on SiC Substrate

    F. Benkhelifa, Fraunhofer Institute
    Stefano Leone, Fraunhofer IAF
    R. Reiner, Fraunhofer Institute
    M. Basler, Fraunhofer Institute
    H. Czap, Fraunhofer Institute
    D. Grieshaber, Fraunhofer Institute
    L. Kirste, Fraunhofer Institute
    Frank Bernhardt, Fraunhofer Institute
    S. Moench, Fraunhofer Institute, University of Stuttgart
    R. Quay, Fraunhofer Institute for Applied Solid State Physics, University of Freiburg

    2A.3 Final.2025

    Abstract
    We present the performances of our GaN MISHEMTs, using a thin buffer grown on SiC substrate, to pave the way for lateral GaN devices to exploit power applications in the voltage range up to 1700 V. Uni- and bi-directional MISHEMTs based on gate and source-connected field plate, with LGD = 21 μm achieve a breakdown voltage over 1800 V at a drain-source and gate currents less than 50 nA/mm. The on-resistance of the 1 mm gate width uni- and bidirectional devices were 9.5 Ω∙mm and 13.5 Ω∙mm, respectively, with a specific on-resistance of 2.7 mΩ∙cm2 and 4.4 mΩ∙cm2, respectively. The 1mm single MISHEMT results in a high Baliga figure of merit (BFOM) of 1.2 GW/cm2. A 147 mm gate width MISHEMT delivered 20 A pulse IDS current, at VGS =0 V and VDS = 1.5 V. Moreover, the MISHEMTs feature encouraging and superior stand in the breakdown voltage vs. on-resistance benchmark to commercial devices. We addressed the potential of the GaN-HEMTs to cover