Dresden 2020 – scientific programme
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DS: Fachverband Dünne Schichten
DS 43: Thin Film Properties: Structure, Morphology and Composition II
DS 43.5: Talk
Thursday, March 19, 2020, 17:45–18:00, CHE 89
Low-temperature growth of Ga2O3 thin films by PEALD — •Ali Mahmoodinezhad1, Christoph Janowitz1, Franziska Naumann2, Paul Plate2, Hassan Gargouri2, Karsten Henkel1, and Jan Ingo Flege1 — 1Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, K.-Zuse-Str. 1, 03046 Cottbus, Germany — 2SENTECH Instruments GmbH, Schwarzschildstraße 2, 12489 Berlin, Germany
Thin films of gallium oxide (Ga2O3) were deposited on silicon (100) through plasma-assisted atomic layer deposition with alternating supply of trimethylgallium and oxygen plasma at low substrate temperatures of 80 to 200 ∘C. The optical and electrical properties as well as the chemical composition of the Ga2O3 films were investigated by spectroscopic ellipsometry (SE), capacitance-voltage (C-V) measurements, and X-ray photoelectron spectroscopy (XPS) documenting the high quality of the films. A constant growth rate of ∼0.66 Å per cycle accompanied by a low inhomogeneity of ≤2% was determined from the SE data for all temperatures. We found a temperature-independent refractive index (1.86±0.01 at 632.8 nm) whereas the optical bandgap decreased with increasing temperature (from 4.68 to 4.57 eV). XPS analysis revealed an almost ideal Ga:O ratio of 2:3 for all temperatures, with the lowest carbon contamination (∼10%) for deposition at 150 ∘C. Furthermore, from the C-V data a permittivity of 9.7±0.2 (at 10 kHz) as well as fixed and mobile oxide charge densities in the order of 1 to 4×1012 cm−2 were deduced.