Radiation effects on microelectromechanical systems
The effects of ionizing radiation and displacement damage are two significant reliability concerns for transducer applications in radiation environments. Microelectromechanical systems (MEMS) are considered as potential transducer candidates for space systems and nuclear reactors. The successful application of MEMS in radiation environments requires that these reliability issues be thoroughly explored and understood. The total-ionizing-dose (TID) effects on piezoelectric micromachined acoustic transducers (pMUTs) and electrothermal microscanners were studied by using experimental characterization of mechanical and electronic property changes due to radiation exposure and calculation of parametric changes. The radiation induced charge accumulation changes the stress distribution in pMUTs and leads to resonant frequency shifts. Also, the charge can move the electrothermal microscanner structures through the electrostatic force and generate additional displacement offset. A new Monte Carlo modeling approach is proposed for analyzing and calculating the defect density generated in suspended monolayer graphene by energetic ion bombardment. The results help the understanding of displacement damage in two dimensional materials.