Deposition and etching characteristic of magnetite thin film for absorptive wire grid polarizer with 45 nm line and space pattern

Magnetite, Fe3O4, is a mineral and one of three commonly naturally occurring oxides of iron. Small grains of magnetite exist in almost all igneous and metamorphic rocks. Most advance studies on magnetite films have focused on the characteristics of films by the growth of crystals such as nanowires. In this study, several processes of the magnetite film and patterning recipes are proposed. The authors deposited the Fe3O4 about 100 nm on the glass wafer using an e-beam evaporator. The 45 nm line/space pattern using nanoimprint process was made, and the residual layer could be reduced up to about 20 nm thickness. In addition, several possible etching gases and optimal conditions are suggested with proper etch selectivity.