We have studied infrared (IR) reflection characteristics of Al films on different multilayers in order to design IR absorber structures which maximize the IR absorption. The Al layers have been deposited on top of thin films composed of crystalline an...
We have studied infrared (IR) reflection characteristics of Al films on different multilayers in order to design IR absorber structures which maximize the IR absorption. The Al layers have been deposited on top of thin films composed of crystalline and amorphous silicon. The Al thicknesses are varied from 0 to 2500 Å. The reflection ratio is estimated by using a measurement system, in which the IR wavelength is set to 1 ㎛. When the Al thicknesses are less than 500 Å, reflection ratios are changed depending on the materials and the optical properties of the multilayers underneath the Al layer. With assuming that the reflection ratio of the Al mirror is 94 % for 1 ㎛-wavelength, the reflection ratios are estimated for the different thin film materials. The ratios are 33.7 % for single crystal Si, 8.4 % for SiO_(2), 23.5 % for poly-silicon, and 32 % for amorphous silicon, respectively. The multilayers with the single crystal layer and the silicon oxide layer underneath the 500 Å-Cluck Al would be suitable structure as the IR absorber membrane for the maximization of the IR reflection.