A method may include providing a patterned feature extending from a substrate plane of a substrate, the patterned feature including a semiconductor portion and a coating in an unhardened state extending along a top region and along sidewall regions of the semiconductor portion; implanting first ions into the coating, the first ions having a first trajectory along a perpendicular to the substrate plane, wherein the first ions form a etch-hardened portion comprising a hardened state disposed along the top region; and directing a reactive etch using second ions at the coating, the second ions having a second trajectory forming a non-zero angle with respect to the perpendicular, wherein the reactive etch removes the etch-hardened portion at a first etch rate, wherein the first etch rate is less than a second etch rate when the second ions are directed in the reactive etch to the top portion in the unhardened state.