Design and Fabrication of MEMS Reflectors for THz Reflect-Arrays

We present the design and fabrication of MEMS reflectors intended to be part of a mechanical terahertz (THz) beam steering reflect-array. Each reflector is shifted by a bidirectional stepwise electrostatic actuator system. The design and functionality of actuator system and reflect-array limit and determine the reflector design. In this paper, we adapt a dicing-free Silicon-on-Insulator (SOI) fabrication process to the requirements of a THz MEMS reflector. We present the partial release of the handle layer from the SOI substrate on wafer level, leaving the remaining connected part as a functional system component. To realize an open interface for the interaction of the reflector with the THz beam, the device layer and the handle layer frame surrounding the SOI chip are partially released during hydrofluoric (HF) vapor etching making a mechanical destruction of the surrounding frame obsolete.