Effects of radiation and cryogenic temperatures on the electromechanical properties of materials used in microsystems

Microelectromechanical systems (MEMS) could prove beneficial for future space missions provided that the effects of radiation and extreme temperatures on the reliability of different devices are well understood. Radiation tests performed on commercial components or on Metal-Insulator-Metal (MIM) structures have revealed the proneness of certain types of MEMS to radiation induced dielectric charging. These extraneous charges can also compromise the functionality of microelectronics and have been studied in thermal oxides and in high-k dielectrics using Metal-Insulator-Semiconductor (MIS) capacitors: a layer structure also present in MEMS devices with transmission lines. Radiation experiments with piezoresistive and Lead Zirconate Titanate (PZT) actuated MEMS also reveal changes in their post-irradiation response. It is thus necessary to investigate the effects of radiation and cryogenic temperatures on the electromechanical properties of thin films and functional materials like sol-gel deposited PZT, Lead Strontium Titanate (PST) ceramics and alternative dielectrics like Al2O3 deposited by atomic layer deposition (ALD).