Methods for forming semiconductor devices, such as FinFETs, are provided. In an embodiment, a fin structure processing method includes removing a portion of a first fin of a plurality of fins formed on a substrate to expose a surface of a remaining portion of the first fin, wherein the fins are adjacent to dielectric material structures formed on the substrate; performing a deposition operation to form features on the surface of the remaining portion of the first fin by depositing a Group III-V semiconductor material in a substrate processing environment; and performing an etching operation to etch the features with an etching gas to form a plurality of openings between adjacent dielectric material structures, wherein the etching operation is performed in the same chamber as the deposition operation.