New theoretical model of the evolution of blazed gratings in the ion beam etching process

Abstract

Blazed gratings play a key role in advanced fields such as metaverse, AR and VR, etc. A good triangular cross section morphology is critical for its performance and applications. To investigate how triangular blazed gratings are evolved from rectangular masks, blazed gratings were fabricated by ion beam etching process. A new theoretical model called six-surface intermediate (SSI) model is proposed to explain the morphological evolution from rectangular homogeneous masks to triangular blazed gratings. The actual morphologies of blazed gratings with different process parameters were characterized by scanning electron microscopy. These observations confirm the correctness of the new model. Our research is of important guiding significance for the fabrication of blazed gratings with controllable morphology.