Duraffourg, L.; Laurent, L.; Moulet, J.-S.; Arcamone, J.; Yon, J.-J. Array of Resonant Electromechanical Nanosystems: A Technological Breakthrough for Uncooled Infrared Imaging. Micromachines2018, 9, 401.
Duraffourg, L.; Laurent, L.; Moulet, J.-S.; Arcamone, J.; Yon, J.-J. Array of Resonant Electromechanical Nanosystems: A Technological Breakthrough for Uncooled Infrared Imaging. Micromachines 2018, 9, 401.
Microbolometer is the most common uncooled infrared technique that allows to achieve 50mK-temperature resolution on the scene. However, this approach has to struggle with both the self-heating inherent to the resistive readout principle and the 1/f noise. We present an alternative approach that consists in using micro / nanoresonators vibrating according to a torsional mode, and whose resonant frequency changes with the incident IR-radiation. Dense arrays of such electromechanical structures were fabricated with a 12µm-pitch at low temperature allowing their integration on CMOS circuits according to a post-processing method. H-shape pixels with 9 µm-long nano-rods and a cross-section of 250 × 30 nm² were fabricated to provide large thermal responses, whose experimental measurements reached up to 1024 Hz/nW. These electromechanical resonators featured a noise equivalent power of 140pW for a response time of less than 1 ms. To our knowledge, these performance are unrivaled with such small dimensions. We also showed that a temperature sensitivity of 20 mK within 100ms-integration time is conceivable at a 12µm-pitch by co-integrating the resonators with their readout electronics and suggesting a new readout scheme. This sensitivity could be reached at short-term by depositing on top of the nano-rods a vanadium oxide layer having a phase-transition that could possibly enhance the thermal response by one order of magnitude.
nano resonator; electromechanical system array; bolometer
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