On going research
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Piezoelectric devices Piezoelectric micromachined ultrasonic transducers (PMUTs) are layered membranes with a piezoelectric active layer used for emitting and receiving ultrasonic waves. |
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Accelerometers Capacitive accelerometers detect external linear acceleration through capacitance variations measurements. We designed a three-axis accelerometer sensor, to be fabricated through surface micromachining, with a single inertial mass, which has a main extension in a plane and is attached to the substrate by flexural and torsional springs that enable two in-plane translations and an out-of-plane rotation. |
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Gyroscopes Lumped mass gyroscope and accelerometer with resonant sensing The structure of the integrated in-plane(y) & out-of-plane(z) accelerometer and of the roll & yaw gyroscope comprises 2 proof masses for differential measure, 4 torsional resonators and 4 beam flexional resonators. |
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Bistable devices Mechanical bistable beams can be used as MEMS shock sensor. A practical way for producing a bistable element is to couple two doubly clamped beam with a deformed initial shape. When an external acceleration reaches a given threshold (say 1000g for the device designed, where g is the acceleration of gravity), the contact force transmitted by the mass to the bistable element induces the transition to a second stable configuration. |
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Magnetometers A Half Double-Ended Tuning Fork design for the sensing part of a Lorentz force magnetometer was adopted as a reference... |
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Resonators MEMS resonators are small electromechanical structures that vibrate at high frequencies, used in many fields. |
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Micropumps The micro-pump we show here is a micro-device of our conception able to suck into and flush out a fluid in a micro-cavity. |
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Micromirrors For electrostatically actuated micromirrors we investigated the effects of residual stresses on their natural frequencies. |
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Modelling & Simulation Over the years we have developed various tools for the modelling and simulation of complex problems in the world of Microsystems. Our expertise goes from the use of commercial codes for multi-physics and nonlinear modelling and simulation to the formulation of ad hoc innovative algorithms and development of relevant simulation codes. |
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Microscale testing We carry out on-chip tests, i.e. tests performed directly on the wafer with the mechanical parts for actuation and sensing built with the same micromachining process used for the MEMS. |
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Adhesion Spontaneous adhesion is especially dangerous in MEMS because of their small dimensions, typically large surface-to-volume ratios, small elastic restoring forces due to microbeam slenderness and close proximity of adjacent surfaces. Recently, we carried out a broad experimental campaign, based on an automatic procedure which is able to obtain the adhesion force (in the usual pull-in/pull-off conditions) for a huge number of cycles with different kinetic energy at the impact. |
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Fracture Polycrystalline silicon is a brittle material. Mechanical parameters linked to failure can be obtained through on-chip testing. A numerical prediction based on a cohesive approach was studied through a research finite element code able to describe the heterogenity of the material. |
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Impact Large scale computations of impact dynamics through multi-level models. Multi-scale simulation of accidental drop impacts. Simplified procedure for a top-down approach with decoupled responses. Assessment of safety against accidental drop applied to the design of accelerometers and microphones. |
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Damping We carried out a precise evaluation of quality factor Q at varying pressure. This theory can be applied to microphones and gyroscopes. Typically, by varying pressure the quality factor changes according to a curve as shown in the following figure. Different source of damping are actually involved at the different pressures. |