On the feasibility of integrated optical waveguide-based in situ monitoring of microelectromechanical systems (MEMS).

摘要

This dissertation explores the feasibility of using integrated optical waveguides to measure the motion of microelectromechanical structures (MEMS). MEMS are a class of silicon devices which are being developed as sensors and actuators. Because these free moving structures are fabricated using processes similar to microfabrication, MEMS devices and traditional electronics can be integrated on the same substrate. This merging of the technologies will allow the miniaturization of large scale mechanical systems. A difficulty with MEMS devices is determining the submicron motion. One method of noninvasive measurement is optical measurement. Research focused on the characterization of one particular MEMS device, a linear comb resonator. Linear comb resonators displace linearly along a single axis when drive with a sinusoidal voltage signal. This research presents how single mode and multimode guided waves have potential to yield significant positional information. Using optical fibers to create a bulk optical metrology probe, the displacement and operating frequency of this device was characterized. Integration of this an optical probe structure with the MEMS devices can create integrated optical metrology (IOM), which is an in-situ method of device characterization and can represent an enabling technology for MEMS. Co-integration of the two technologies can be achieved through either processing or post processing of integrated waveguides with the MEMS devices. The fabrication process for co-integration of polymer optical waveguides has been experimentally defined in this dissertation, however final results indicate guides wave IOM would best be explored through process interruption or hybrid techniques given existing polymer materials. Analysis yields that the co-integration of inorganic waveguide structures first requires optimization of the design of the microprobe layout.