【Epitaxy Papers】Fabrication of β-Ga₂O₃/air-gap structures on (010) β-Ga₂O₃ by wet etching in tetramethylammonium hydroxide (TMAH)

      Researchers from the National Institute for Materials Science have published a dissertation titled " Fabrication of β-Ga₂O₃/air-gap structures on (010) β-Ga₂O₃ by wet etching in tetramethylammonium hydroxide (TMAH)" in Applied Physics Express.

Abstract

      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.

DOI：

https://doi.org/10.35848/1882-0786/ae1e59