Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster I

HL 13.27: Poster

Monday, March 18, 2024, 15:00–18:00, Poster E

Heteroepitaxial Growth of Ge-doped γ-Ga₂O₃ Ultrawide Bandgap Semiconductor Thin Films on (100) MgAl₂O₄ Substrates by Pulsed Laser Deposition — •Jingjing Yu, Sijun Luo, and Marius Grundmann — Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth System Sciences, Universität Leipzig, 04103 Leipzig

γ-Ga₂O₃ is a defective cubic spinel metastable phase of ultrawide bandgap gallium oxides. In order to compensate the volatile loss of Ge components, a Ge-rich target with a Ge:Ga atomic ratio of about 17:1 was used to grow (100)-oriented γ-(Ga_1.73Ge_0.27)O₃ epitaxial thin films on cubic spinel (100) MgAl₂O₄ substrates using pulsed laser deposition. The (Ga_1.73Ge_0.27)O₃ epitaxial thin films are fully-strained, and the in-plane orientation relationships are [010] (Ga_1.73Ge_0.27)O₃ // [010] MgAl₂O₄ and [011] (Ga_1.73Ge_0.27)O₃ // [011] MgAl₂O₄. The 215 nm thick (100) (Ga_1.73Ge_0.27)O₃ epitaxial thin film shows the rocking curve of (400) reflection with a full width at half maximum (FWHM) of about 0.022 degrees ( 80 arcseconds). The electrical properties of (Ga_1.73Ge_0.27)O₃ epitaxial thin film were evaluated by temperature-dependent Hall measurements. The resistivity of film decreases dramatically from about 30000 Ω cm to 6 Ω cm as temperature increases from 125 to 350 K. The electron carrier concentration of thin film increases from 2.1 x 10¹⁴ cm⁻³ at 125 K to 2.6 x 10¹⁷ cm⁻³ at 350 K with an estimated activation energy of about 117 meV. While the Hall electron carrier mobility gradually increases from 0.4 to 4.1 cm² V⁻¹s⁻¹ as the temperature increases from 125 to 350 K.