| While advantages such as good thermal stability and processing-chemical compatibilities exist for common monolithic-integrated micro-electro-mechanically tunable filters (MEM-TF) and MEM-tunable vertical cavity surface emitting lasers (MT-VCSEL), they often require full processing to determine device characteristics. Alternatively, the MEM actuators and the optical parts may be fabricated separately, then subsequently bonded. This "hybrid approach" potentially increases design flexibility by allowing wafer-level pre-testing and discarding defective parts prior to completing device fabrication. A hybrid MT-VCSEL's resonant frequency has less sensitivity to growth variations than a monolithic design. Monolithic electrostatically actuated devices are also typically limited to one-third of the original air-gap spacing between the tuning reflector and optically active material. In contrast, a hybrid approach enables electrostatic pull-in voltage to be designed independent of the air-gap between the tuning reflector and optically active or reflective material. Electrostatically actuated monolithic devices suffer catastrophic failure when pull-in occurs. In addition to the use of polySi dimples to prevent stiction, a key advantage of these dimples is they may also be used to eliminate catastrophic failure. Since hybrid techniques allow integration of heterogeneous material systems, "best of breed" compound optoelectronic devices may be customized to enable materials groups to be optimized for tasks for which they are best suited. Thus, as a first step toward a hybrid (AlxGa 1-xAs-polySi) MT-VCSEL, this dissertation reports the design, fabrication, and demonstration of an electrostatically actuated hybrid MEM-TF. A 250x250-mum2, 4.92-mum-thick, Al0.4Ga0.6As-GaAs distributed Bragg reflector was successfully flip-bonded to a polySi piston electrostatic actuator using SU-8 photoresist as bonding adhesive. The device demonstrated 53nm (936.5--989.5nm) of resonant wavelength tuning over the actuation voltage range of 0 to 10 V. |
