In this work we develop surface-micromachinedRF MEMS switches in III-V technology making use ofmaterials which can be alternative to the ones commonly used.In this way, some technological constraints concerning RFMEMS reliability can be overcome. Specifically, we evaluatethe potential of tantalum nitride (TaN) and tantalumpentoxide (Ta2O5) to be used for the switches actuation padsand dielectric layers, respectively. To this scope, acompositional, structural and electrical characterization ofTaN and Ta2O5 films as a function of the depositionparameters (temperature, sputtering mixture composition, andfilm thickness) is performed. Both shunt and series switchesare prepared and show good switching capabilities by apreliminary analysis. The complete device characterization isin progress and will be presented.

In this work we proposed design, fabrication and functional characterization of a very low cost energy autonomous, maintenance free, flexible and wearable micro thermoelectric generator (mu TEG), finalized to power very low consumption electronics ambient assisted living (AAL) applications. The prototype. integrating an array of 100 thin films thermocouples of Sb(2)Te(3) and Bi(2)Te(3), generates, at 40 degrees C, an open circuit output voltage of 430 mV and an electrical output power up to 32 nW with matched load. In real operation conditions of prototype, which are believed to be very close to a thermal gradient of 15 degrees C. the device generates an open circuit output voltage of about 160 mV, with an electrical output power up to 4.18 nW.In the first part of work, deposition investigation Sb(2)T(e)3 and Bi(2)Te(3) thin films alloys on Kapton HN polyimide foil by RF magnetron co-sputtering technique is discussed. Deposition parameters have been optimized to gain perfect stoichiometric ratio and high thermoelectric power factor: fabricated thermo-generator has been tested at low gradient conditioned to evaluate applications like human skin wearable power generator for ambient assisted living applications.

In this work, the evolution of the Au assisted-growth of ZnO nanorods deposited by vapour phase deposition both on sapphire and on indium-tin-oxide on glass (ITO-glass) substrates has been studied. Our investigation demonstrates that the growth proceeds first as a 3D growth, giving rise to a buffer layer, few microns thick, formed by ZnO grains with different orientation. Then a 1D transition occurs with the nucleation of a dense array of vertically aligned nanorods. A different degree of crystalline order and nanorods alignment was found between the samples grown on ITO-glass and sapphire substrates, which was ascribed to the different morphology that the Au seed layer acquires on the two different substrates. A semi-quantitative analysis of the ZnO crystalline orientation was carried out by X-ray diffraction (XRD) measurements performed at fixed incidence configuration and supported by high resolution scanning electron microscopy (HR-SEM) investigations on focused ion beam (FIB) prepared cross-sections.

The potential of sputtered Ta2O5 thin films to be used as dielectric layers in capacitive radio frequency microelectromechanical system switches is evaluated by investigating two factors of crucial importance for the performance of these devices which are the transport mechanisms and the charging effects in the dielectric layer. We find that Ta2O5 films show good electrical and dielectrical properties for the considered application in terms of a low leakage current density of 4 nA/cm(2) for E=1 MV/cm, a high breakdown field of 4 MV/cm and a high dielectric constant of 32. For electric fields lower than 1 MV/cm the conduction mechanism is found to be variable-range hopping in the temperature range 300-400 K, while nearest-neighbor hopping is observed at higher temperatures. For fields in the range 1-4 MV/cm Poole-Frenkel becomes the dominant conduction mechanism. Current and capacitance transients used to investigate the charging effects show a decay which is well described by the stretched-exponential law, thus providing further insights on capture and emission processes.