Increasing the Sensitivity of SiO2/Al Micro Cantilever Infrared Detector Based on Micro Electromechanical Systems Technology by Optimizing of Dimensions

In this paper, the sensitivity of the micro-cantilever infrared detector has been increased by optimizing its geometric dimension. The detector's main body consists of an absorbing area, bi-material, and isolation legs, which are made up of silicon dioxide. Bi-material regions (absorbing area and bi-material legs) include a thin film layer of aluminum, which is placed on the main body layer. In this detector, the amount of bending at the end of the tip detector depends on the thickness of insulating and metal layers and the width of isolating and bi-material legs. Furthermore, it has been proved that the detector's displacement and sensitivity are optimized when the thickness of the metal layer is selected the half of the thickness of the absorbing layer. The results of the calculations show that by applying boundary conditions for 100 pW/μm2 constant thermal flux on the absorber, amount of displacement, thermomechanical, power, displacement, and body temperature sensitivities are increased by 26%, 27%, 28%, 2.3%, and 26%, respectively. In addition, the calculation results show that the sensitivities and response time are improved to 4.24, 54, 12.4, 12.8, 54, 4.2, 54.48, 54, and 1.5 times, respectively, in the vacuum environment if the leg’s width, the isolating and metal layers’ thicknesses are selected as 1μm, 0.1μm, and 0.05μm, respectively.