Optik okumalı termo-mekanik termal detektör dizin tasarımı ve fabrikasyonu

Thesis TitleThermal Detector Arrays with Optical ReadoutAbstractInfrared (IR) imaging technology has found many important application areas such asmilitary, automobile heads-up-displays (HUD), medical diagnostics, surveillance forsecurity, victim search for rescue teams, non-destructive testing for industrialapplications, and geo-thermal event detection for environmental control.In this thesis, design and realization of an uncooled opto-mechanical IR detectorwith optical readout is presented. It is shown that our calculated noise equivalenttemperature difference (NETD) is <10 mK including the readout noise sources (assuming50um pixels, f/1 optics and 60Hz frame rate). This performance level is far superior tothe other current state-of-the-art uncooled microbolometer-based detector arrays and iscomparable to that of the best cooled IR detector arrays, which are far more complicatedand expensive compared to the uncooled counterparts. In addition to the high-performance, the architecture proposed is scalable to high-resolutions as the pixel readoutis based on an integrated diffraction grating and the pixelated readout electronics iscompletely eliminated by the use of MEMS scanners for the serial pixel readout.The detector pixels are tiny membranes that are connected to bimaterial legs, whichare connected to a substrate through thermal isolation legs. The conversion of IRradiation into temperature difference causes deflection along bimaterial legs. Themechanical deflection is detected optically with sub-nm accuracy using diffractiongratings placed underneath each pixel. Fixed diffraction gratings and the movable pixelmembrane form an interferometer. This type of interferometric readout offers operation atdetector shot-noise limit using a coherent light source, thus the contribution of thereadout noise to the overall system noise level is negligible. Another important advantageof the optical readout is that electrical conductive paths that increase the thermalconduction are not needed. Thus higher sensitivity compared to microbolometers andsome of the cooled detectors can be obtained.As the design prototypes, different design variations for single pixels and small arraysof 3 x 3 pixels were fabricated. The microfabrication was done at MicroelectronicsResearch Center (MIRC), Georgia Institute of Technology, Atlanta-USA. Themicrofabrication requires 4-lithography masks and uses the following standard ICmaterials: Silicon Nitride, Aluminum, and Chromium on top of Quartz substrate and islimited to low temperature processes that are below 250 ºC.Keywords: Infrared imaging, thermal image sensors, infrared absorber, bimaterialcantilevers, thermal deformation, diffraction grating, interferometer, microscanners,MEMS, microfabrication.Advisor: Hakan Ürey Date: 08/11/2005Director: Date: