Smoothening mechanism for GaAs(100) surfaces during ion-enhanced plasma etching

摘要

We present experimental data showing the development of smooth surfaces on GaAs(100) exposed simultaneously to ion bombardment and reactive species in chlorine plasma. With negligible ion bombardment, the surface develops < 110 > ridges and {111} facets, as in purely chemical etching. With ion bombardment at energy 27 eV, formation of ridges and facets is reduced, and at 110 eV the etched (100) surface has a root-mean-square roughness of 0.5 nm. Kinetic Monte Carlo simulations suggest that low energy ion bombardment modifies the relative ratios of reaction rates at specific sites from their purely chemical values to give the smooth surface.