Growth mechanism and characteristics of β-Ga2O3 heteroepitaxailly grown on sapphire by metalorganic chemical vapor deposition

Ray Hua Horng*, Dong Sing Wuu, Po Liang Liu, Apoorva Sood, Fu Gow Tarntair, Yu Hsuan Chen, Singh Jitendra Pratap, Ching Lien Hsiao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

In this study, monoclinic gallium oxide (β-Ga2O3) epilayer was successfully grown on c-plane, (0001), sapphire substrate by metalorganic chemical vapor deposition (MOCVD) with interplaying growth temperature, TEGa flow rate, and growth time. X-ray diffraction 2θ scans show only three narrow diffraction peaks referred to β-Ga2O3(2¯ 01), (4¯ 02), and (6¯ 03) in all epilayers, indicating a superior crystalline quality. Current-voltage (I–V) measurement reveals that these β-Ga2O3 films are insulating and exhibit high resistance in a range of 1012–1014 Ω. The crystallization characteristics of the epilayers can be effectively improved with thickness through increasing TEGa flow rate and growth time, which was evidenced by X-ray rocking curves and I–V measurements. However, the surface roughness of β-Ga2O3 film increases with growth time and TEGa flow rate. When the growth temperature increases above 825 °C, the thickness of β-Ga2O3 film decreases clearly. Furthermore, it can be found that the growth rate decreased as the growth time increasing. The growth mechanism based on first-principles calculation was proposed as that 3D growth induced by the lattice mismatch between β-Ga2O3 and sapphire starts at nucleation stage, and follows up a lateral growth promoting a 2D growth after the thick epilayer being grown. In addition, the complex chemical reaction between TEGa and oxygen precursors was unraveled by density function theory calculation.

Original languageEnglish
Article number100320
JournalMaterials Today Advances
Volume16
DOIs
StatePublished - Dec 2022

Keywords

  • Crystalline
  • Gallium oxide
  • Growth mechanism
  • Metalorganic chemical vapor deposition
  • Roughness

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