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We demonstrated the fabrication of β-Ga2O3/air-gap structures on (010) β-Ga2O3 substrates through sequential dry etching and crystallographic wet etching. Wet etching in a 25 wt% tetramethylammonium hydroxide solution at 90 °C yielded a lateral-to-vertical etch-rate ratio of approximately 11 when the lateral direction was aligned with [001]. This pronounced lateral etching enabled the undercutting of dry-etched β-Ga2O3 mesas to form cantilevers and air bridges extending along [201], which is perpendicular to [001]. This etch-only process using standard device-fabrication equipment offers a straightforward route for fabricating β-Ga2O3/air-gap structures that are promising for microelectromechanical systems.

Rights:

• Creative Commons BY Attribution 4.0 International
  

Keyword: Ga2O3, TMAH, wet etching, MEMS

Date published: 2025-11-01

Publisher: IOP Publishing

Journal:

• Applied Physics Express (ISSN: 18820778) vol. 18 issue. 11 116501

Funding:

• Japan Society for the Promotion of Science JP24K01368

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.35848/1882-0786/ae1e59

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Updated at: 2025-11-27 08:30:13 +0900

Published on MDR: 2025-11-27 08:24:04 +0900