Abstract
A process for high aspect ratio reactive ion etching of molecular beam epitaxially (MBE) grown GaAs and AlGaAs materials using a mixture of methane and hydrogen is described. The process utilises a positive photoresist which can withstand 7 mu m mesa etching of GaAs/Al0.3Ga0.7As and is simple to remove in acetone or oxygen plasmas. This eliminates the need for plasma-enhanced chemical vapour deposition (PECVD) mask technology.