Analytical solution for response of ferroelectric thin film to infrared radiation

Micro-bolometer pixel is an essential element in the infrared focal plane array (IRFPA) of infrared detectors. Its response to infrared radiation is analyzed in this paper. The pixel structure is modeled as a composite laminate thin plate whose sides are measured with the thickness from 0.1-1 μm. Its middle ply is a ferroelectric thin film. Its top surface is covered with a gold or platinum infrared absorber, while the bottom surface is deposited with platinum or lanthanum-nickel. Meanwhile both surfaces are a pair of electrodes. The top surface receives infrared radiation pulses successively. For the very tiny micro bolometer pixel, it is assumed that the infrared radiation is uniformly distributed on the plate. Furthermore, as the ratio of the side length to the thickness of the plate is dramatically large, it is assumed that heat transfer only takes place across the thickness of the plate. The thermal-electric-mechanical coupling governing equations are solved in a form of Fourier series. Results of the displacement, temperature variation and electric output signals of the micro bolometer pixel structure under infrared radiation are obtained, analyzed and compared with experimental data.