A Multistep DRIE Process for Complex Terahertz Waveguide Components

A silicon deep reactive-ion etching (DRIE) process has been developed, using multiple SiO
₂
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.