Design and Fabrication of Silicon-Based Triangular Lattice Photonic Crystals Using Electron Beam Lithography and Reactive Ion Etching

This study presents the theoretical modeling and fabrication of an efficient silicon-based photonic crystal waveguide. The structure consists of a two-dimensional triangular lattice of air holes etched into a silicon substrate, with a lattice constant of 400 nm and rod radius of 160 nm, designed to precisely control light propagation. Various defect configurations—such as point defects, missing lattice elements, and shape-modified holes—are introduced to tailor the photonic bandgap and enable waveguiding functionalities. The fabrication process employs high-resolution electron beam lithography (EBL) followed by capacitive coupled reactive ion etching (RIE). Special attention is given to mitigating the proximity effect and optimizing the electron dose parameters to achieve high pattern fidelity. The results contribute to the scalable fabrication of nanophotonic devices for integrated photonic circuits.