A Multistep DRIE Process for Complex Terahertz Waveguide Components

Abstract

A silicon deep reactive-ion etching (DRIE) process has been developed, using multiple SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> masks to enable multidepth waveguide features with ±2% tolerance. The unique capability of this process is demonstrated by designing, fabricating, and testing an orthomode transducer working in the 500-600 GHz frequency range. Straight waveguide measurements are also performed to characterize the losses associated with the multistep DRIE process, giving results slightly better than expected for metal-machined waveguides. This process enables the integration of multiple terahertz waveguide components such as mixers, multipliers, quadrature hybrids, and polarization twists onto a single silicon package.