Thermo-mechanical analysis of uncooled La0.67Sr0.33MnO3 microbolometer made on circular SOI membrane

We report on thermal and mechanical analysis of uncooled antenna-coupled La0.67Sr0.33MnO3 microbolometer made on circular SOI (Silicon On Insulator) membrane with no limitation in its active area (circular membrane with diameter up to 2 500 μm). A simple method how to investigate the thermal conversion efficiency (thermal resistance value - Rth) is introduced. Thermal analysis is supported by the ANSYS modelling and simulation. It is found that Rth and thermal time constant (τ) of our LSMO microbolometer (bolometer sensitivity and time response) can be tuned by the SOI membrane thickness. Rth value as high as 188 K/mW and τ value as low as 0.88 ms are estimated from the thermal simulation for SOI membrane with total thickness of 300 nm (SiO2-200 nm, Si-100 nm). Genesis of the induced mechanical stress changes after main processing steps is found and evaluated to explain the mechanical stability of the LSMO based MEMS microbolometer.