Nickel Plating on Silicon for Fabricating an Infrared Wire-Grid Polarizer

An IR polarizer was fabricated by plating a Ni wire-grid on a Si substrate. The Si surface was processed by photolithography to create grooves with ∼200 nm width, ∼200 nm spacing, and ∼300 nm depth. After surface treatment, the Si plate was put in a plating bath for ∼5 min to fill the grooves with Ni. The excess Ni film that was deposited outside the grooves was removed by mechanical polishing. The fabricated wire-grid exhibited a polarization function with an extinction ratio of 15–20 dB in the 3–13 µm wavelength range.