NIR silicon photodetector enhancement using photonic crystal cavity resonators
Author(s)Al Johani, Ebrahim Dakhil.
Massachusetts Institute of Technology. Department of Physics.
Rajeev J. Ram and Marin Soljačić.
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The growing demand for efficient infrared sensors for light ranging, thermal-cameras, and soon, free-space optical communications has yet to be answered. In this study, we use polycrystalline silicon in conjunction with a photonic crystal cavity (PhCC) to enhance light absorption for efficient sensing. We present a cost-effective alternative to the current III-V detectors. By adding a 2D-PhC resonator layer, surface-illuminated light can be confined within a 10 micron region with great intensity, leading to a higher effective path-length and improved detector responsivity. More than 1000 variants of this detector are designed and implemented in a 65nm CMOS process. Using a nearest neighbor method, we find the optimized designs. We validate experimental findings by simulating mode behavior of the PhCC structures using FDTD models. In addition, a numerical study on cavity parameter optimization for achieving high Q-factors and extinction ratios specifically for surface-illumination is presented. We report polysilicon PhCC-enhanced sensors with Q-factors of 6500 resulting in responsivities at 1300nm up to 0.13mA/W -a 25x improvement over non-resonant surface-illuminated Silicon detectors.
Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019Cataloged from PDF of thesis. "The Table of Contents does not accurately represent the page numbering"--Disclaimer page.Includes bibliographical references (pages 45-47).
DepartmentMassachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology