Résumé
We have demonstrated a process for the fabrication of sub-micron structures using high resolution etching to transfer patterns by masking with a bilayer of Titanium and SiNX. Reactive ion etching (RIE) was performed on GaN epilayers grown on (0001) sapphire by metal organic vapour phase epitaxy (MOVPE). Various chemistries were used to etch GaN including: HBr, SiCl4/HBr, CH4/H-2, NH3/CH4/H-2 and CH4/H-2/O-2 I?Patterns including pillars, holes and gratings with feature: sizes ranging from 200 nm to 1 mu m were produced. In a CH4/H-2 plasma, quasi-vertical etching was achieved with sidewall angles greater than 81 degrees.