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MOCVD growth and band offsets of κ-phase Ga2O3 on c-plane sapphire, GaN- and AlN-on-sapphire, and (100) YSZ substrates.
- Source :
- Journal of Vacuum Science & Technology: Part A-Vacuums, Surfaces & Films; Dec2022, Vol. 40 Issue 6, p1-16, 16p
- Publication Year :
- 2022
-
Abstract
- Epitaxial growth of κ-phase Ga<subscript>2</subscript>O<subscript>3</subscript> thin films is investigated on c-plane sapphire, GaN- and AlN-on-sapphire, and (100) oriented yttria stabilized zirconia (YSZ) substrates via metalorganic chemical vapor deposition. The structural and surface morphological properties are investigated by comprehensive material characterization. Phase pure κ-Ga<subscript>2</subscript>O<subscript>3</subscript> films are successfully grown on GaN-, AlN-on-sapphire, and YSZ substrates through a systematical tuning of growth parameters including the precursor molar flow rates, chamber pressure, and growth temperature, whereas the growth on c-sapphire substrates leads to a mixture of β- and κ-polymorphs of Ga<subscript>2</subscript>O<subscript>3</subscript> under the investigated growth conditions. The influence of the crystalline structure, surface morphology, and roughness of κ-Ga<subscript>2</subscript>O<subscript>3</subscript> films grown on different substrates are investigated as a function of precursor flow rate. High-resolution scanning transmission electron microscopy imaging of κ-Ga<subscript>2</subscript>O<subscript>3</subscript> films reveals abrupt interfaces between the epitaxial film and the sapphire, GaN, and YSZ substrates. The growth of single crystal orthorhombic κ-Ga<subscript>2</subscript>O<subscript>3</subscript> films is confirmed by analyzing the scanning transmission electron microscopy nanodiffraction pattern. The chemical composition, surface stoichiometry, and bandgap energies of κ-Ga<subscript>2</subscript>O<subscript>3</subscript> thin films grown on different substrates are studied by high-resolution x-ray photoelectron spectroscopy (XPS) measurements. The type-II (staggered) band alignments at three interfaces between κ-Ga<subscript>2</subscript>O<subscript>3</subscript> and c-sapphire, AlN, and YSZ substrates are determined by XPS, with an exception of κ-Ga<subscript>2</subscript>O<subscript>3</subscript>/GaN interface, which shows type-I (straddling) band alignment. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 07342101
- Volume :
- 40
- Issue :
- 6
- Database :
- Complementary Index
- Journal :
- Journal of Vacuum Science & Technology: Part A-Vacuums, Surfaces & Films
- Publication Type :
- Academic Journal
- Accession number :
- 160370651
- Full Text :
- https://doi.org/10.1116/6.0002106