Digital etching of GaAs

The self-limited etching characteristics and the surface processes in digital etching employing an UV laser/Cl2/GaAs system are summarized. The self-limiting nature is the key mechanism and plays an important role in digital etching for obtaining an etch rate independent of etching parameters as well as atomic layer epitaxy. The model proposed for digital etching is photodissociation of physisorbed chlorine on GaAs with diffusion of negatively charged Cl into GaAs.