Atomic layer etching of GaAs(110) with Br2 studied by scanning tunneling microscopy

Abstract

Scanning tunneling microscopy studies of GaAs(110) exposed to Br2 at 720 K show preferential etching at single-height [1̄12] and [001] steps with little etching at double-height steps. Etching in the [11̄0] direction is at least ∼4.5 times faster than in the [001] direction, producing rectangular etch pits. For higher Br2 exposures, etching is dominated by single-height step flow but triangular double-layer etch pits also form on extended terraces.