Journal article

Publication year: 2020

Journal: Journal of Vacuum Science & Technology A

Volume number: 38

Issue number: 6

ISSN: 0734-2101

eISSN: 1520-8559

DOI Link: https://doi.org/10.1116/6.0000619

Publisher: American Vacuum Society

Abstract: 
The wide bandgap of oxide semiconductors enables solid-state devices with functionalities beyond the reach of technologically more well-established materials such as silicon, germanium, or gallium nitride. These functionalities, among others, include optical transparency paving the way for transparent (opto-)electronics like ultraviolet light emitters or solar-blind detectors as well as large breakdown fields enabling high-power electronic applications. In particular, Ga2O3 is considered as oxide compatible with the nitride III-V materials. As a particular challenge, Ga2O3 may crystallize in different polymorphs. All possess large optical bandgaps beyond 4.8eV and, thus, are of great interest for such devices. Nowadays, Ga2O3 thin films are prepared by a plethora of different synthesis methods including physical as well as chemical variants, however, reports on a controlled manufacturing process of individual Ga2O3 phases with sputtering techniques are currently scarce. Here, we grow Ga2O3 thin films by ion-beam sputtering on sapphire substrates of different orientation and demonstrate that selective controlled synthesis of different Ga2O3 polymorphs is feasible. The monoclinic beta -phase and the corundum-type alpha -phase are stabilized when deposited on (0001) and (10-10) sapphire substrates, respectively. A stacking rather than a mixture of both phases is observed when thin films of alpha -phase exceed a certain thickness. Thus, thickness control enables the transition between the two phases. The proposed technique holds promise for ion-beam sputter methods to be employed in Ga2O3-related device build-up.

Harvard Citation style: Becker, M., Benz, S., Chen, L., Polity, A., Klar, P. and Chatterjee, S. (2020) Controlled thin-film deposition of α or β Ga₂O₃ by ion-beam sputtering, Journal of Vacuum Science & Technology A, 38(6), Article 063412. https://doi.org/10.1116/6.0000619

APA Citation style: Becker, M., Benz, S., Chen, L., Polity, A., Klar, P., & Chatterjee, S. (2020). Controlled thin-film deposition of α or β Ga₂O₃ by ion-beam sputtering. Journal of Vacuum Science & Technology A. 38(6), Article 063412. https://doi.org/10.1116/6.0000619