Disclosed herein are approaches for modifying patterned features using a directional etch. In one approach, a method may include providing a stack of layers of a semiconductor device, forming an opening through the stack of layers, the opening defined by a first sidewall and a second sidewall, and delivering ions into the first sidewall in a reactive ion etching process. The ions maybe delivered at a first non-zero angle relative to a perpendicular extending from the substrate, wherein the reactive ion etching process removes a first portion of the stack of layers from just a lower section of the first sidewall.