Supercritical fluid deposition for conformal Cu film formation on sub-millimeter-scale structures used to fabricate terahertz waveguides

Abstract

A small-volume hot-wall batch reactor with excess precursor loading was proposed for supercritical fluid deposition (SCFD) of Cu during the fabrication of sub-millimeter-scale, metal-coated terahertz (THz) wave devices. Conformal film formation was experimentally demonstrated, validating our method. Our method enables a much higher precursor concentration (at least 20 mol/m3) than the conventional method (below 2 mol/m3), facilitating conformal film formation on sub-millimeter structures. Kinetic analysis revealed that our proposed method was applicable for fabricating rectangular metal-coated THz waveguides; furthermore, it was promising for monolithically integrated THz wave devices.