National and Kapodistrian University of Athens Semiconductor and Microsystems Laboratory Solid State Physics Section Department of Solid State Physics Department of Solid State Physics, Faculty of Physics, University of Athens University of Athens, School of Science, Faculty of Physics, Department of Solid State Physics, Contact, Maps Penepistimiopolis Zografos, Athens 15784 | Phone: +30 210 7276-722 | Fax: +30 210 7276-711 Semiconducting Materials Semiconductor Devices MEMS Nanocomposites Reliability     Materials and     Transport parameters     Point defects     Dielectric films Micro-Electro-Mechanical System Switches (MEMS) Device research The research activity focuses mainly on the issue of dielectric charging in Micro-Electro-Mechanical System (MEMS) capacitive switches. The charging is investigated: (i) in devices with a wide range of dielectric materials such as * Si₃N₄ and SiO₂ deposited under different conditions, such as temperature, PECVD frequency and gas flow ratios * AlN and Al₂O₃  * nanostructured dielectrics such as:    - nanocrystalline diamond,    - TiO₂ and    - Si₃N₄ with embeded nanoparticles (ii) in floating electrode devices (iii) on the effect of field emission, in devices being in up- state with and without dielectric film, and its impact on dielectric charging (vi) with moving armature in down-state (contacted charging) and up-state (contact-less charging) The research activities also include: * the impact of the presence of a floating electrode and the condition of pull-in state, when activation is performed through the transmission line, is also investigated * the actuation in dielectric-less and pillar-less devices * the calculation of discharge current through the dielectric film The parameters tested are: *   Capacitance - Voltage characteristics in vacuum and temperature range of 100K to 450K *   Capacitance - Voltage characteristics in different gas ambient and temperature range of 300K to 450K *   Measurement of dielectric film surface potential by applying the Kelvin Probe model *   Direct measurement of dielectric film surface potential decay with Kelvin Probe setup *   Direct measurement of top electrode potential decay with Kelvin Probe setup *   Lifetime test through cycling under different stress bias, switching frequencies and duty cycles *   All assessment are performed  in the temperature range of 100 K to 450 K under vacuum or 300K to 450K under controlled environment such as nitrogen, controlled humidity etc. next MEMS capacitive switch Discharge current thrugh the dielectric film in a MEMS capacitive switch Shift of bias for capacitance minimum in up-state resulting from dielectric film discharge Structure for field emission studies in MEMS