CMOS-SOI-MEMS Thermal Antenna and Sensor for Uncooled THz Imaging

• Published in: IEEE transactions on electron devices 2016-03, Vol.63 (3), p.1260-1265
• Main Authors: Svetlitza, Alexander, Blank, Tanya, Stolyarova, Sara, Brouk, Igor, Bar-Lev Shefi, Sharon, Nemirovsky, Yael
• Format: Article
• Language: English
• Subjects: Absorption; Antennas; Arrays; CMOS; Devices; Electric power generation; Etching; frequency-selective surfaces (FSSs); Imaging; Infrared imaging systems; Metallizing; microfabrication; Micromechanical devices; microsensors; MOS devices; Sensors; Silicon Over Insulator; Thermal properties; Thermal resistance; Thermal sensors; THz sensors
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2015.2513051

We report the design (electrical, mechanical, and thermal) and characterization of an improved performance uncooled thermal sensor for THz radiation based on thermal antenna. The 2-D imager pixel array provides the periodicity and constitutes a frequency-selective surface tuned to the desired THz wavelength band. The focal-plane array is first fabricated in a matured 0.18-μm CMOS-Silicon Over Insulator (SOI) process. By applying MEMS postprocessing using the CMOS metallization layers as built-in masks, micromachined-suspended directly absorbing resistive antennae integrated with thermal sensors are obtained, thus achieving good thermal isolation as well as low thermal mass. Characterization is performed using blackbody operating at 900-1200 K and THz filters. In contrast to the earlier published results, the reported device is characterized with a fully blocking set of three THz filters. With the current responsivity of ~2.6 A/W, Noise Equivalent Power (NEP) of the order of NEP/√Hz| 1 Hz = 6.1 pW/√Hz, D* of 0.41·10 10 cm√Hz/W, this uncooled THz sensor in the standard CMOS-SOI technology may enable monolithic uncooled passive THz imagers.