Reliability design of RF-MEMS switches
for space applications (REDEMS)
Project objectives
Technical University of Cluj-Napoca

National Institute for Research and Development in Microtechnology, IMT Bucharest
The project objectives are included in 6 work packages are described here after.

O1: Theoretical models development of mechanical properties, dynamical response, fatigue and energy dissipation for different operating conditions.
The space conditions influences on mechanical properties of MEMS components from switching applications are identified. Theoretical formulas for mechanical properties of microcomponents from switching applications are developed considering the influence of operating conditions as temperature, medium preasure, humidity and vibrations. Identification of new theoretical approaches is performed in other to characterize the fatigue of MEMS switches and their lifetime in space applications. Multiphysics analysis of MEMS switch behaviour are performed considering thermo-electro-mechanical coupling. Statical model developed includes stress and strain analysis, stiffness and compliance, and the variation of Young's modulus for different operating conditions. The dynamical model include the frequency response, dynamical stress and fatigue, quality factor and the loss energy considering different operating conditions.

O2: Theoretical models development of contact adhesion and stiction prediction risk of MEMS switches used in space applications. Modeling and analysis of adhesion and friction of MEMS switches from space applications is performed. The material properties and surface characteristics have influence on the adhesion between switch components. The material properties and surface asperities depend by temperature. Humidity changes the adhesion forces. The medium presiure has influence on pull-in and on stiction. Considering different operating conditions, Hertz theory and the existing adhesion models (JKR, DMT) a new model for stiction prediction for specific operating conditions from space will be developed.

O3: Fabrication of MEMS flexible structure used in switching applications. Components used in switching applications are fabricated. Firstly, using the geometrical characteristics and the recommended materials provided from theoretical analysis, MEMS components used in switch applications are fabricated. Microcantilevers, microbridge and micromembranes with different geometrical characteristics will be fabricated using specific MEMS technologies. These samples will be mechanical tested in order to investigate their behavior in different operating conditions. Secondly, thin films are deposited from different MEMS materials for tribological investigations. Stiction and friction asfunction of different temperature and humidity will be characterized. Dense ultrathin films such as single monolayer films are obtained using physical vapor deposition and chemical vapor deposition.

O4: Mechanical and tribological testing of MEMS flexible structure in different space conditions. To characterize the mechanical and tribological behaviour of MEMS switch in different operating conditions advance testing equipments are used. The tests are performed in clean-rooms using equipments such as Atomic Force Microscope, Vibrometer Analyzer and Nanoindenter. The other facitities for tests are:  climatic chamber CH-160; thermal shock chamber TSE-11-A; free fall shock machine; highly accelerated stress test chamber with temperature, pressure and humidity control; mobile thermal airstream system; thermal control system based on Peltier elements; electrodynamic vibration system with thermal and electrical tests.

O5: Optimal design of a reliable MEMS switch for space applications, prototype fabrication and its experimental validation. Firstly, based on theoretical and experimental results, optimizations of the MEMS materials and structures are performed in order to obtain a reliable MEMS switch for space applications. A specific software which exists at the Optimal Design Center from the coordinator host institute will be used. Multiobjective optimizations are performed to increase the accuracy response of MEMS switch from space applications and their lifetime. Secondly, the prototype of a reliable MEMS switch for space applications is fabricated. After the prototype testing in different operating conditions its patenting is considering.

O6: Technological transfer and industrial implementation. Technological transfer of the project results to manufacturing companies is considered. Industrial implementation in a target space application as (sattelite) is considered at the end of project. Suport of industrial implementation of product is done by the project partners with industrial partners. For this, collaborations with Department of Aerospace from Liege and with Centrum of Spece from Liege are already disccused.
Agentia Spatiala Româna
Space Technology and Advanced Research - Programme for Research, Development and Innovation - STAR