Design and Fabrication Considerations for Thermo-Resistive Pixel Detectors for Room Temperature Directional Long Wavelength IR Sensing

• Published in: IEEE sensors journal Vol. 21; no. 4; pp. 4257 - 4266
• Main Authors: Vosoogh-Grayli, Siamack, Leach, Gary W., Bahreyni, Behraad
• Format: Journal Article
• Language: English
• Published: New York IEEE 15-02-2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Detectors; Directional sensor; Heating systems; infrared sensing; machine vision; Mathematical model; MEMS; Micromachining; Photoresists; Pixels; Robot sensing systems; Robotics; Room temperature; Sol-gel processes; Task complexity; Temperature sensors; thermo-resistive
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2020.3029433

Rapid growth in application demands for smart sensing has fostered the development of micro-electromechanical-based devices with unique capabilities. Recent developments have led to complex autonomous systems that require a variety of intelligent sensing tasks to render human-machine interactions safe and efficient in workplace environments comprising both a human and robotic workforce. Here we report the design and fabrication of a novel thermo-resistive LWIR detector, for sensing and recalculating the direction of incident LWIR radiation for potential robotic applications. The work employs standard silicon micromachining processes along with sol-gel chemistry to fabricate three-dimensional pixel detectors to approximate an LWIR source's direction of incidence using thermo-resistive material. There have been no prior reports of the thermo-resistive effect in conjunction with directionality in LWIR sensors. In addition to the fabrication process flow, we describe the mathematical framework for sensor operation and present a photoresist deposition process for large 3-D topographic surface structures. We discuss the advantages and challenges of the currently designed and fabricated prototypes and highlight issues that limit their angular LWIR response.