Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Oxide Semiconductors I

HL 25.9: Talk

Wednesday, March 20, 2024, 12:00–12:15, ER 325

Screening of contact metals for optimized performance of α-Ga2O3 based Schottky Barrier Diodes — •Sebastian Köpp, Clemens Petersen, Sofie Vogt, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Felix Bloch Institute for Solid State Physics, Semiconductor Physics Group, Leipzig, Germany

We present α-Ga2O3:Sn based Schottky barrier diodes with exceptional current rectification ratios of up to 8 orders of magnitude and high mean barrier heights of up to 2.53 eV. By evaluating various Schottky metals, we find that reactively sputtered Pt/PtOx yields the best performing Schottky barrier diodes [1]. We further show temperature dependent IV-measurements in the range of 40 K-400 K that are in agreement with the thermionic emission model. The effective barrier heights could accurately be fitted using the laterally inhomogeneous barrier model [2].
In recent years the metastable corundum-structured α-phase of Ga2O3 has shown to have promising physical properties. With a bandgap of 5.3-5.6 eV [3,4] and a predicted breakdown field of 10 MV/cm it surpasses the theoretical limits of β-Ga2O3 in terms of Baliga’s figure of merit [4]. Further, α-Ga2O3 is isostructural to α-Al2O3 and hence epitaxial growth on cost-efficient sapphire substrates is feasible.

[1] S. Koepp et al., J. Vac. Sci. Technol. A 41, 043411 (2023)
[2] D. Splith et al., Phys. Status Solidi A, 218: 2100121 (2021)
[3] A. Segura et al., Phys. Rev. Materials 1, 024604 (2017)
[4] E. Ahmadi et al., J. Appl. Phys. 126, 160901 (2019)

Keywords: Gallium oxide; Schottky diode