Structural and electrical properties of thick κ-Ga2O3 grown on GaN/sapphire templates
Abstract
Thick (23 µm) films of κ-Ga2O3 were grown by Halide Vapor Phase Epitaxy (HVPE) on GaN/sapphire templates at 630 °C. X-ray analysis confirmed the formation of single-phase κ-Ga2O3 with half-widths of the high-resolution x-ray diffraction (004), (006), and (008) symmetric reflections of 4.5 arc min and asymmetric (027) reflection of 14 arc min. Orthorhombic κ-Ga2O3 polymorph formation was confirmed from analysis of the Kikuchi diffraction pattern in electron backscattering diffraction. Secondary electron imaging indicated a reasonably flat surface morphology with a few (area density ∼103 cm−2) approximately circular (diameter ∼50–100 µm) uncoalesced regions, containing κ-Ga2O3 columns with in-plane dimensions and a height of about 10 µm. Micro-cathodoluminescence (MCL) spectra showed a wide 2–3.5 eV band that could be deconvoluted into narrower bands peaked at 2.59, 2.66, 2.86, and 3.12 eV. Ni Schottky diodes prepared on the films showed good rectification but a high series resistance. The films had a thin near-surface region dominated by Ec − 0.7 eV deep centers and a deeper region (∼2 µm from the surface) dominated by shallow donors with concentrations of ≤1016 cm−3. Photocurrent and photocapacitance spectra showed the presence of deep compensating acceptors with optical ionization energies of ∼1.35 and 2.3 eV, the latter being close to the energy of one of the MCL bands. Deep level transient spectroscopy revealed deep traps with energies near 0.3, 0.6, 0.7, 0.8, and 1 eV from the conduction band edge. The results show the potential of HVPE to grow very thick κ-Ga2O3 on GaN/sapphire templates.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 01, 2022
- Source ID
- 10.1063/5.0091653
Entities
People
- A. V. Chikiryaka
- A. Y. Polyakov
- A.A. Vasil'ev
- Eugene Yakimov
- I. V. Shchemerov
- M. P. Scheglov
- S. I. Stepanov
- Stephen Pearton
- А. I. Kochkova
- А. В. Черных
- А. И. Печников
- В. И. Николаев
Organizations
- Defense Threat Reduction Agency
- Ioffe Institute
- National Science Foundation
- National University of Science and Technology
- Russian Academy of Sciences
- Russian Science Foundation
- University of Florida