M. Aqib

University of Houston, DEVCOM Army Research Laboratory

  • 7A.5 – Crack-Free AlN Thin Films on Si Substrates for Large-Area Ultrawide-Bandgap Semiconductor Template

    M. Aqib, University of Houston, DEVCOM Army Research Laboratory
    M. Moradnia, University of Houston, Texas Center for Superconductivity at UH
    M. Ji, DEVCOM Army Research Laboratory
    V. S. Parameshwaran, DEVCOM Army Research Laboratory
    W. L. Sarney, DEVCOM Army Research Laboratory
    S. Pouladi, University of Houston, Texas Center for Superconductivity at UH
    N. -I. Kim, University of Houston, Texas Center for Superconductivity at UH
    G. A. Garrett, DEVCOM Army Research Laboratory
    A. V. Sampath, DEVCOM Army Research Laboratory
    R. Forrest, University of Houston, Department of Physics
    J. -H. Ryou, University of Houston, TcSUH. AMI

    7A.5 Final.2025

    Abstract
    This study presents a model developed to analyze crack formation during the heteroepitaxial growth of ultrawide-bandgap (UWBG) III-N semiconductor films on Si substrates. It addresses the challenges of growing thick (~>1.5 μm) crack-free AlN films, which is crucial for integrating Si with UWBG semiconductors. Utilizing Griffith theory of brittle fracture and Mathews-Blakeslee theory of dislocations, the model predicts crack formation in 500-nm AlN films driven by in-plane tensile stress during the cool-down process after deposition. To prevent this, a ductile epitaxial interlayer is introduced to modify the tensile strain in the AlN film. This approach successfully demonstrates the epitaxial growth of 1.5-μm single-crystalline, crack-free AlN film on a Si substrate.