Martin Kuball

University of Bristol
  • GaN-on-diamond: the correlation between interfacial toughness and thermal resistance

    Daniel Francis, Akash Systems, San Francisco, CA, USA
    Daniel Field, University of Bristol
    Caho Yuan, University of Bristol
    Roland Simon, Thermap Solutions
    Daniel Twitchen, Element Six Ltd.
    Firooz Faili, Element Six Technologies, Santa Clara, CA
    Dong Liu, University of Oxford, University of Bristol
    Martin Kuball, University of Bristol

    A nanoindentation induced blistering method has been used to extract the GaN/diamond interfacial toughness (adhesion energy) from four types of GaN-on-diamond samples with varying SiNx interlayer thicknesses. The mode I energy release rate (GIC) was quantified and is presented. Additionally, transient thermoreflectance has been used to measure the thermal boundary resistance (TBR) between the GaN and the diamond substrate. It was found that a thin SiNx interlayer resulted in a lower TBR (15 m2 K GW-1) whilst maintaining a reasonable interfacial toughness (1.4±0.5 J m-2). For interlayers of a similar thickness, samples with a high interfacial toughness and high residual stresses in the GaN had a smaller TBR. This indicates that the intrinsic interfacial characteristics that enhanced the interfacial toughness could be beneficial in improving the TBR.

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  • May 12, 2022 // 3:20pm

    18.12 GaN-on-Si Membranes for Power Device Applications: Stress Evolution throughout Fabrication

    Jerome Cuenca, Cardiff University, Cardiff, UK
    Oliver Williams, Cardiff University, Cardiff, UK
    Martin Kuball, University of Bristol
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  • May 11, 2022 // 5:30pm

    12.4 Novel thermoreflectance-based method for in-situ die attach thermal conductivity assessment in packaged devices

    Zeina Abdallah, University of Bristol
    Nathawat Poopakdec, University of Bristol, Bristol, UK and Navaminda Kasatriyadhiraj Royal Air Force Academny
    Martin Kuball, University of Bristol
    James Pomeroy, University of Bristol
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  • May 12, 2022 // 11:30am

    14.3 Dynamic Ron in AlGaN/GaN Structure with Different Layer Thickness

    Hyun-Seop Kim, University of Bristol, Bristol, UK
    Hassan Hirshy, IQE, Cardiff, UK
    Andrew Withey, Nexperia Newport Wafer Fab, Newport, UK
    Robert Harper, Compound Semiconductor Centre, Cardiff, UK
    Sam Evans, Nexperia Newport Wafer Fab, Newport, UK
    Martin Kuball, University of Bristol
    Michael J Uren, University of Bristol
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  • 12.1.2023 Thermal management in GaN-devices for increased power density

    Mohamadali Malakoutian, Stanford University, Stanford, CA,
    Xiang Zheng, University of Bristol, Bristol
    Martin Kuball, University of Bristol
    S. Chowdhury, Stanford University, Stanford, CA; University of Bristol, Bristol, UK

    12.1.2023 Invited Talk_Srabanti Chowdhury_final

  • 12.3.2023 Characterization of a Novel Thermal Interface Material based on Nanoparticles for High Power Device Package Assembly

    Zeina Abdallah, University of Bristol
    James Pomeroy, University of Bristol
    Nicolas Blasakis, Adamant Composite Ltd.
    Athanasios Baltopoulos, Adamant Composite Ltd.
    Antonios Vavouliotis, Adamant Composite Ltd.
    Martin Kuball, University of Bristol

    12.3.2023 CS_MANTECH_2023_final_Zeina_Abdallah

  • 15.2.2023 Selective Area Growth of B-Ga2O3

    Arpit Nandi, University of Bristol
    Indraneel Sanyal, University of Bristol
    Martin Kuball, University of Bristol

    15.2.2023_SAG of Ga2O3_Arpit Nandi_CDTR -W_Rev1

  • 10.1.3.2024 3D Diamond Growth for GaN Cooling and TBR Reduction

    Daniel Francis, Akash Systems, San Francisco, CA, USA
    Sai Charan Vanjari, University of Bristol
    Xiaoyang Ji, University of Bristol
    Tatyana Feygelson, U. S. Naval Research Laboratory
    Joseph Spencer, U.S. Naval Research Laboratory
    Hannah N. Masten, National Research Council Postdoctoral Fellow, Residing at NRL
    Alan Jacobs, U.S. Naval Research Laboratory
    James Spencer Lundh, National Research Council Postdoctoral Fellow, Residing at NRL
    Marko Tadjer, U.S. Naval Research Laboratory
    Travis J. Anderson, U.S. Naval Research Laboratory
    Karl D. Hobart, U.S. Naval Research Laboratory
    Bradford Pate, Naval Research Laboratory
    James Pomeroy, University of Bristol
    Matthew Smith, University of Bristol
    Martin Kuball, University of Bristol
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  • 10.1.4.2024 Thermal Dissipation Enhancement Using a Metal-Diamond Composite Heat Spreaders in High-Power RF MMICs

    Zeina Abdallah, University of Bristol
    James Pomeroy, University of Bristol
    Martin Kuball, University of Bristol
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  • 11.2.2.2024 Mapping of Local Threshold Voltage in AlGaN/GaN HEMTs

    Anjali Anjali, University of Bristol
    James Pomeroy, University of Bristol
    Jr-Tai Chen, SweGaN AB
    Martin Kuball, University of Bristol
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  • 11.2.3.2024 Time-Dependent Conduction Mechanisms in Superlattice Layers on 200 mm Engineered Substrates

    Zequan Chen, University of Bristol
    Peng Huang, University of Bristol
    Indraneel Sanyal, University of Bristol
    Matthew Smith, University of Bristol
    Michael J Uren, University of Bristol
    A. Vohra, imec, Leuven, Belgium
    Benoit Bakeroot, imec, Leuven, Belgium and CMST, imec & Ghent University, Ghent, Belgium
    Martin Kuball, University of Bristol
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