US Patent 11171010 Controlled hardmask shaping to create tapered slanted fins

Embodiments described herein relate to methods forming optical device structures. One embodiment of the method includes exposing a substrate to ions at an ion angle relative to a surface normal of a surface of the substrate to form an initial depth of a plurality of depths. A patterned mask is disposed over the substrate and includes two or more projections defining exposed portions of the substrate or a device layer disposed on the substrate. Each projection has a trailing edge at a bottom surface contacting the device layer, a leading edge at a top surface of each projection, and a height from the top surface to the device layer. Exposing the substrate to ions at the ion angle is repeated to form at least one subsequent depth of the plurality of depths.