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Title: Electrical and Structural Properties of Two-Inch Diameter (0001) α-Ga 2 O 3 Films Doped with Sn and Grown by Halide Epitaxy
Two-inch diameter α -Ga 2 O 3 films with thickness ∼4 μ m were grown on basal plane sapphire by Halide Vapor Phase Epitaxy (HVPE) and doped with Sn in the top ∼1 μ m from the surface. These films were characterized with High-Resolution X-ray Diffraction (HRXRD), Scanning Electron Microscope (SEM) imaging in the Secondary Electron (SE) and Micro-cathodoluminescence (MCL) modes, contactless sheet resistivity mapping, capacitance-voltage, current-voltage, admittance spectra, and Deep Level Transient Spectroscopy (DLTS) measurements. The edge and screw dislocations densities estimated from HRXRD data were respectively 7.4 × 10 9 cm −2 and 1.5 × 10 7 cm −2 , while the films had a smooth surface with a low density (∼10 3 cm −2 ) of circular openings with diameters between 10 and 100 μ m. The sheet resistivity of the films varied over the entire 2-inch diameter from 200 to 500 Ω square −1 . The net donor concentration was ∼10 18 cm −3 near the surface and increased to ∼4 × 10 18 cm −3 deeper inside the sample. The deep traps observed in admittance and DLTS spectra had levels at E c −0.25 eV and E c −0.35 eV, with concentration ∼10 15 cm more » −3 and E c −1 eV with concentration ∼10 16 cm −3 . « less
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ECS Journal of Solid State Science and Technology
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National Science Foundation
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Fig. 3(b) shows the tunneling probability T according to the Kane two-band model in the three materials, In0.53Ga0.47As, GaAs, and GaN, following our observation of a similar electroluminescence mechanism in GaN/AlN RTDs (due to strong polarization field of wurtzite structures) [8]. The expression is Tinter = (2/9)∙exp[(-2 ∙Ug 2 ∙me)/(2h∙P∙E)], where Ug is the bandgap energy, P is the valence-to-conduction-band momentum matrix element, and E is the electric field. Values for the highest calculated internal E fields for the InGaAs and GaN are also shown, indicating that Tinter in those structures approaches values of ~10-5. As shown, a GaAs RTD would require an internal field of ~6×105 V/cm, which is rarely realized in standard GaAs RTDs, perhaps explaining why there have been few if any reports of room-temperature electroluminescence in the GaAs devices. [1] E.R. Brown,et al., Appl. Phys. Lett., vol. 58, 2291, 1991. [5] S. Sze, Physics of Semiconductor Devices, 2nd Ed. 12.2.1 (Wiley, 1981). [2] M. Feiginov et al., Appl. Phys. Lett., 99, 233506, 2011. [6] L. Coldren, Diode Lasers and Photonic Integrated Circuits, (Wiley, 1995). [3] Y. Nishida et al., Nature Sci. Reports, 9, 18125, 2019. [7] E.O. Kane, J. of Appl. Phy 32, 83 (1961). [4] P. Fakhimi, et al., 2019 DRC Conference Digest. [8] T. Growden, et al., Nature Light: Science & Applications 7, 17150 (2018). [5] S. Sze, Physics of Semiconductor Devices, 2nd Ed. 12.2.1 (Wiley, 1981). [6] L. Coldren, Diode Lasers and Photonic Integrated Circuits, (Wiley, 1995). [7] E.O. Kane, J. of Appl. Phy 32, 83 (1961). [8] T. Growden, et al., Nature Light: Science & Applications 7, 17150 (2018).« less
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