Study on Improving the Absorption Efficiency of Uncooled Infrared Sensor by Using Grating

When heated by incoming IR radiation, an uncooled infrared sensor changes the temperature variation into a voltage or a current signal, which is detected by the readout circuit. Uncooled infrared sensors are usually made by building cantilevers on CMOS circuits. However, their performance is limited by the low absorption efficiency. To improve the absorption efficiency of an uncooled infrared sensor, the surface-plasmon-resonance structure is proposed in this paper. By COMSOL, the variation of the infrared absorption efficient with the structure parameters is simulated and analyzed. An absorption efficient of 98% within a specified spectral band and 30.5% averaged within the whole wavelength range is reached by parameter optimization.