Effect of Oxidation, Etching, and Thin-Film Deposition on Silicon Photonic Crystals

Abstract

The effects of oxidation, partial oxide etching, and thin-film deposition on the photonic bandgap of two-dimensional triangular photonic crystals are studied. Two structures, air cylinders in silicon background and silicon cylinders in air background, are analyzed by the plane wave expansion method. Fine tuning of the bandgap is demonstrated by varying the thickness of the interfacial layers of grown by thermal oxidation and produced by atomic layer deposition (ALD). In the air cylinder structure the absolute bandgap can be tuned from 0 to during oxidation by varying the oxide thickness from 0 to , where is the lattice constant. During etching it can be tuned from 0 to . In a silicon cylinder structure the transverse magnetic bandgap can be tuned from 0 to during oxidation and from 0 to during etching. Tuning of the defect frequency of a single defect formed by selective oxidation is demonstrated, and the dependence of the defect frequency on the thickness of the oxide is investigated. Results indicate that the effect of complementary metal oxide semiconductor compatible processes such as thermal oxidation and ALD on the photonic bandgap is significant.