[TuP3G] Oxide Materials & Devices

[TuP3G-15] V-shaped grooves formed on (−102) β-Ga₂O₃ using TMAH wet etching

〇Takayoshi Oshima¹ (1. NIMS (Japan))

We demonstrated the formation of V-grooves on (−102) β-Ga2O3 substrates using wet etching in a heated tetramethylammonium hydroxide (TMAH). The (−102)-oriented substrate exhibited a faster wet etch rate than those of the commercially available (100), (010), (001), (−201)-oriented ones, making it favorable for wet-etch patterning. We found that well-defined V-shaped trenches consisting of (001) and (−201) facets were formed when the etching windows were aligned along the [010] direction. Unlike dry-etch-based patterning processes, this wet-etch-based crystallographic etching method is not equipment-dependent and therefore enables highly reproducible fabrication of V-grooves. Considering the wide bandgap of β-Ga₂O₃, the proposed technique has potential applications in transmission blazed gratings and V-shaped trench metal–oxide–semiconductor field-effect transistors (MOSFETs).