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Optimizing the Stoichiometry of Ga 2 O 3 Grown by RF‐Magnetron Sputter Deposition by Correlating Optical Properties and Growth Parameters
Author(s) -
Schurig Philipp,
Couturier Marcel,
Becker Martin,
Polity Angelika,
Klar Peter Jens
Publication year - 2019
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201900385
Subject(s) - materials science , sputtering , sputter deposition , argon , thin film , analytical chemistry (journal) , sapphire , stoichiometry , refractive index , cavity magnetron , deposition (geology) , high power impulse magnetron sputtering , ceramic , dispersion (optics) , optoelectronics , optics , metallurgy , chemistry , laser , nanotechnology , paleontology , physics , organic chemistry , chromatography , sediment , biology
β‐Ga 2 O 3 thin films are deposited by radiofrequency (RF)‐magnetron sputtering on quartz and c‐sapphire substrates using a ceramic stoichiometric Ga 2 O 3 target and a constant flux of argon process gas. Oxygen flux, heater power, and sputtering power are varied in the synthesis of the layers. The resulting Ga 2 O 3 layers are analyzed in terms of their structural and optical properties. Based on this analysis, the process parameters leading to the formation of an optimized β‐Ga 2 O 3 layer are identified. The main challenge in obtaining the stoichiometric β‐Ga 2 O 3 thin films by sputter deposition is to overcome the influence of a strong preferential sputtering of Ga from the ceramic target. This can be achieved by adding a suitable fraction of oxygen to the argon process gas used in the deposition process. Furthermore, it is demonstrated that the refractive index dispersion of β‐Ga 2 O 3 depends strongly on its composition. Thus, a combined analysis of refractive index dispersion and optical bandgap position may serve as a valuable preliminary probe of the thin film's composition.