Fabrication techniques for creating a thermally isolated TM-FPA (thermal microphotonic focal plane array)

A novel fabrication strategy has produced optical microring-resonator-based thermal detectors. The detectors are based on the thermo-optic effect and are thermally isolated from a silicon wafer substrate so as to maximize the temperature excursion for a given amount of incident radiation and minimize the impact of thermal phonon noise. The combination of high-Q, thermal isolation, and lack of Johnson noise offers thermal microphotonic detectors the potential to achieve significantly greater room temperature sensitivity than standard bolometric techniques. Several batch fabrication strategies were investigated for producing thermal microphotonic detectors using waveguide materials such as LPCVD Silicon Nitride (Si3N4) on Oxide and Silicon on Insulator (SOI). Fabrication challenges and loss reduction strategies will be presented along with some initial infrared detection results.