The Effect of Tetramethylammonium Hydroxide Treatment on Photoelectrochemical Etched Gallium Nitride Trench Structures

摘要

The effect of posttreatment of photoelectrochemical etched GaN trench structures was examined. A 5.8- μm-thick n-type GaN epitaxial layer with a nominal Si concentration of 1.5×10^{16cm-3, grown on an n-GaN substrate, was etched by photoelectrochemical reaction through a Ti etching mask. A 25 wt% aqueous solution of tetramethylammonium hydroxide (TMAH) was used for posttreatment at 85 °C for 30 minutes. A cross-section of the TMAH-treated GaN trenches showed fine vertical sidewalls along the m-axis. These results suggest that TMAH posttreatment is useful for realizing GaN vertical trench structures.}