PROJECT DESCRIPTION

Microsensors and actuators play a key role in the economy of the future due to their small sizes, low fabrication costs and versatility. The applications generally include: thermal, pressure, chemical and biosensors. Microsensors and actuators use multiple physical effects for producing the intended sensing or transducing effect. Their approach involves multidisciplinary areas as fluid flow, electronics, piezoelectricity, chemistry, electrochemistry. The coupling different physical effects in a single structure is challenging, regarding both the constructive solutions and the integration and interface selection for the use in fast and accurate analyses. MEMS devices are micro-electro-mechanical systems that can be used in many applications such as sensors and actuators. In general, MEMS involve both electric and non-electric parts and perform functions that include sensing, actuating, signal processing, displaying, and controlling. MEMS devices can be used in chemical, mechanical and medical applications.

The purpose of this project it is the development of new applications in the domain of sensors and actuators fabricated in microsystems technologies, MEMS (micro-electro-mechanical systems), based on microcantilever or an area of cantilevers. Sensors (actuators) based on cantilevers can generate sensing platforms for a multitude of physical dimensions, or chemical, or biochemical with a high sensitivity, portables and cheaply, which can revolutionise, for example, medical diagnosis domain. The microcantilevers are 3D elements devices, manufacturing using a variety of processes as micromachinig technologies.

The project follows the realisation of a lot of applications in micromechanical, instrumentation, gas detection domain and biomedical domain. The cantilever structures can be manufactured by lithographic processes from microelectronics combined with micromachining. To obtaining the three-dimensional devices, thin-film deposition, isotropic and anisotropic etching and wafer-bonding techniques are used to make the moving parts. Silicon is commonly used material in these processes but other materials such as silicon dioxide, silicon nitride, aluminium, and some polymers are often used in MEMS. The project aim is to develop research activities for applications for environment control, biomedical domain and instrumentation domain. The microcantilevers will be fabricated using three different techniques: silicon front side etching with crystallographic orientation <100>, surface micromachining and bulk micromachining. We shall use wafers of Si and SOI . The main structure of the cantilever will be fabricated with silicon, but will be investigated new materials like polymers. For the sensing layer will be utilised piezoelectric layers or different sensitive materials, biological materials. Bimorf (two layers with materials with different thermal coefficients of expansion, for which will be realised coupled thermo-mechanical analyses) and unimorf cantilevers will be fabricated. The applications will use the properties of the cantilever as reaction to forces and mass changes. Will be detected: oscillation frequency or mechanical changes like bending of cantilever as a result of the compressive or tensile stress induce by the sensitive layer, which reacting to a chemical stimulus, or which, by bio functionality can be detected molecules, microorganisms or AND. After choosing the optimal configurations for specific applications will shall perform simulations with a dedicated program for simulations micromechanical as CoventorWare, which is already acquired by the consortium. Investigations/characterisations for bio and piezoelectric materials, and technological processes for fabrication will be done.