Diode-based microbolometer with performance enhanced by broadband metamaterial absorber

This Letter reports a microbolometer integrated with a broadband metamaterial absorber (MMA) to enhance its performance, which contains series-connected silicon diodes as the temperature sensor. The broadband MMA is readily integrated into the device by introducing an array of different-sized square resonators on the silicon nitride structural layer, while the widened titanium interconnecting wires between individual diodes serve as the ground plane. In a comparative experiment, the broadband MMA was demonstrated to be superior to the ordinary silicon nitride absorber in a broad spectra range, especially in a long-wavelength IR regime, which directly leads to an increase in IR responsivity by 60%. More importantly, this enhancement in responsivity was achieved with no sacrifice of the response time due to the negligible thermal mass of the introduced resonator array. (C) 2016 Optical Society of America