No Cover Image

Journal article 98 views 11 downloads

Scalable Growth and Properties of (AlxGa1−x)2O3 Thin Films on 2- and 4-Inch Sapphire via Close-Coupled Showerhead MOCVD

Ciaran Llewelyn Orcid Logo, Zdenko Zápražný, Edmund Dobročka, Filip Gucmann, Dan Lamb Orcid Logo

physica status solidi (a), Volume: 223, Issue: 6

Swansea University Authors: Ciaran Llewelyn Orcid Logo, Dan Lamb Orcid Logo

  • 71413.VoR.pdf

    PDF | Version of Record

    © 2026 The Author(s). This is an open access article under the terms of the Creative Commons Attribution License.

    Download (5.26MB)

Check full text

DOI (Published version): 10.1002/pssa.202500608

Abstract

A series of (AlxGa1−x)2O3 thin films were deposited using an AIXTRON Close-Coupled Showerhead (CCS) metalorganic chemical vapour deposition (MOCVD) system to study aluminium (Al) incorporation into the β-Ga2O3 lattice. Films ≈1.2 μm thick were grown on 2-inch and 4-inch c-plane sapphire substrates....

Full description

Published in: physica status solidi (a)
ISSN: 1862-6300 1862-6319
Published: Wiley 2026
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa71413
Abstract: A series of (AlxGa1−x)2O3 thin films were deposited using an AIXTRON Close-Coupled Showerhead (CCS) metalorganic chemical vapour deposition (MOCVD) system to study aluminium (Al) incorporation into the β-Ga2O3 lattice. Films ≈1.2 μm thick were grown on 2-inch and 4-inch c-plane sapphire substrates. A linear relationship between film composition and precursor ratio indicated near-ideal alloying behaviour. Growth kinetics were composition-dependent, where Al incorporation reduced growth rates compared to gallium (Ga), although pure Al2O3 grew faster than intermediate alloys. The films exhibited high optical transmittance (82–88%), with a tuneable bandgap increasing with Al content. Morphological changes and increased roughness were observed up to Al x = 0.42, suggesting a possible phase transition. X-ray diffraction, rocking curve measurements and pole figure confirmed the monoclinic β-phase for the Ga2O3 only film, with strong, well-defined Bragg peaks. For Al2O3, only the substrate and nucleation layer reflections were visible, consistent with epitaxial Al2O3 growth on sapphire. The largest rocking curve full width half maximum was observed for samples with Al content x equals 0.12 and 0.42, which can be correlated with significant changes in the thin film surface morphology. The successful extension from 2-inch to 4-inch wafers highlights the scalability and uniformity of the CCS MOCVD process.
Keywords: 4-inch sapphire; aluminium gallium oxide; gallium oxide; MOCVD; semiconductors
College: Faculty of Science and Engineering
Funders: Engineering and Physical Sciences Research Council. Grant Number: EP/T019085/1; Agentúra na Podporu Výskumu a Vývoja. Grant Numbers: APVV-24-0325, SK-TW-RD-24-0006
Issue: 6