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

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.