Growth and Characterization of Beta-Gallium Oxide Thin Films Using Plasma-Assisted Molecular Beam Epitaxy

Master's Thesis

Abstract

In this work, we present the heteroepitaxial and homoepitaxial growth and characterization of single crystal Ga2O3 by plasma-assisted molecular beam epitaxy (MBE). For growth, flux-temperature measurements were done on Ga, In, and Sn cells to find the appropriate temperature for a specific beam equivalent pressure (BEP). In the first set of experiments, (201) and (100) Ga2O3 thin films were grown on c-plane (001) sapphire and (100) 􀀀Ga2O3 substrates, respectively. Samples were grown at a constant oxygen flux of 1.5e-􀀀5 (Torr) and substrate temperature of 700C. Four different gallium fluxes (2e-􀀀8, 5e-8, 8e-8, and1.1e-7 (Torr)) were investigated. Optical spectroscopy, atomic force microscopy (AFM), scanning (SEM); transmission electron microscopy (TEM), and xray diffraction (XRD) were done on samples. The characterizations showed lower growth rate at higher gallium fluxes and smoother surfaces at lower gallium fluxes for both heteroepitaxy and homoepitaxy. In the next step, different dopants (Si, In, and Sn) were studied for doping. Data analysis showed successful incorporation of Si atoms in Ga2O3 crystal structure. However, further investigations revealed that Si atoms did not act as dopants. On the other hand, Ga2O3 could be doped n-type with Sn. Also, Ga2O3 thin films could be successfully delta-doped by Sn. While GaSnO/Ga2O3 heterostructures could be successfully grown on (001) sapphire substrate by alloying of Sn into Ga2O3 crystal structure, InGaO/Ga2O3 could not be achieved due to non-uniform distribution of In inside the Ga2O3 crystal.

Attributes

Attribute NameValues
URN
  • etd-03062015-120701

Author Kasra Pourang
Advisor Debdeep Jena
Contributor Debdeep Jena, Committee Chair
Contributor Gregory L. Snider, Committee Member
Contributor Grace Xing, Committee Member
Degree Level Master's Thesis
Degree Discipline Electrical Engineering
Degree Name MSEE
Defense Date
  • 2015-02-20

Submission Date 2015-03-06
Country
  • United States of America

Subject
  • Plasma MBE

  • Gallium oxide

Publisher
  • University of Notre Dame

Language
  • English

Record Visibility Public
Content License
  • All rights reserved

Departments and Units

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