Universal scaling relationship for atomic layer etching

Atomic layer etching (ALE) is a multistep process used for removing ultrathin layers of the material. The removal step can be driven by ion bombardment, typically with energies of <100 eV and step times of >1 s. Previously, we reported a new ALE operating regime where exposures to ion energies were >500 eV and step times were <1 s. This paper provides a simple theoretical basis for unifying the low energy/long exposure and high energy/short exposure ALE regimes. This insight is captured in a scaling relationship that expands the concept of an ALE processing window and the corresponding application space.