Embodiments described herein relate generally to methods for etching structures and the structures formed thereby. In some embodiments, an etch selectivity between a first portion of a material and a second portion of the material is increased. Increasing the etch selectivity includes performing an anisotropic treatment, such as an anisotropic ion implantation, on the material to treat the first portion of the material, and the second portion of the material remains untreated after the anisotropic treatment. After increasing the etch selectivity, the first portion of the material is etched. The etching may be a wet or dry etch, and may further be isotropic or anisotropic.