Scientific dissemination


NIRVANA at MEMS 2016 and at Inertial Sensors 2016

Two months rich in dissemination activities: the following papers were given as plenary talks at the two most relevant conferences in the field of MEMS and Inertial Sensors

 

MEMS 2016:

Reliability of gyroscopes based on piezoresistive nano-gauges against shock and free-drop tests

INERTIAL SENSORS 2016: 

Analysis of Gyrocompassing through Miniaturized MEMS Based on Piezoresistive Sensing

 

 

 

   


NIRVANA at Transducers 2015

The following plenary talk will be given at Transducers 2015:

 

VIBRATIONS REJECTION IN GYROSCOPES BASED ON PIEZORESISTIVE NANOGAUGES

 

Abstract—The work discusses the effects of vibrations on the performance of rate gyroscopes in terms of Allan variance, and presents the results of vibrations rejection on a Z-axis gyroscope based on piezoresistive nano-gauge sensing elements. In a comparative analysis with a consumer off-the-shelf gyroscope, the proposed device shows a 10-fold better angle random walk (ARW) under no vibrations, and at least a 100-fold better Allan variance, when acquired under vibration amplitude of ±6 g (gravity units), at frequencies up to 10 kHz.

 

 

   


NIRVANA plenary talk at MEMS 2015

The following plenary talk will be given at MEMS 2015, Lisboa.

 

LARGE FULL SCALE, LINEARITY AND CROSS-AXIS REJECTION IN LOW-POWER 3-AXIS GYROSCOPES BASED ON NANOSCALE PIEZORESISTORS

 

Abstract—This work presents in-plane and out-of-plane Coriolis rate gyroscopes based on nano-scale piezoresistive readout and using an eutectic bonding between the bottom wafer, where the sensor is formed, and the cap wafer, where routing and metal pads are fabricated. The gyroscopes feature a novel design with a central levered sense frame, to maximize the device symmetry and compactness. The position of the piezoresistive nanogauges along the lever system optimizes the scale-factor. Operation on a ± 3000 dps full-scale-range (FSR) demonstrates quite competitive performance, with a linearity error lower than 0.25% and a cross-axis rejection 50x better than state-of-the art consumer gyroscopes.

 

 

   


Third NIRVANA publication on JMEMS

The following paper has been accepted for publication in the Journal of Microelectromechanical Systems.

Wow!: the paper was elected as the best one in the December 2015 issue of JMEMS! Thanks to this achievement, t will be an open-access article for everybody for a limited amount of time!

 

In-Plane and Out-of-Plane MEMS Gyroscopes Based on Piezoresistive NEMS Detection

 

Abstract—This paper presents a new design and a complete characterization of amplitude-modulation gyroscopes based on piezoresistive nanogauges. The working principle and optimization criteria of in-plane and out-of-plane devices relying on double frame decoupling and levered sense mode are discussed in light of sensitivity and resolution theoretical predictions. The architecture of driving and sensing electronics is also presented. The reduced thermo-mechanical damping with respect to capacitive configurations, and the inherently high output signal leads to white noise performance in the mdps/√Hz range within an area smaller than 0.35 mm^2, at pressures in the millibar range. Sub-5-ppm linearity errors within 1000 dps are also demonstrated.

 

 

   


A second NIRVANA publication on JMEMS

The following paper has been accepted for publication in the Journal of Microelectromechanical Systems.

 

Fatigue in Nanometric Single-Crystal Silicon Layers and Beams

 

Abstract—This paper extends the experimental evidences of fatigue in micrometric structural silicon, typical of microelectromechanical systems processes, down to the submicrometric scale. The rationale lies in two naïve considerations. Fatigue is not observed at the macroscale, but becomes evident at the microscale. Thus, it should occur even more evidently at the nanoscale, where critical crack lengths decrease and if it becomes more evident, it may allow a deeper insight on the still debated origin of this phenomenon. Two suitable test structures, including 250-nm-thick notches and beams, are designed, fabricated, and subject to a fatigue campaign. Results on 34 samples show failures within a few minutes (at 20 kHz) for applied stresses as low as 38% of the measured nominal strength.

 

 

   


NIRVANA Presentation at Eurosensors 2014

The following paper has been accepted for presentation at the Eurosensors conference.

 

Linearity of piezoresistive nano-gauges for MEMS sensors 

 

Abstract—Piezoresistive sensing through sub-micrometric Silicon beams was demonstrated as a possible alternative to parallel-plate sensing capacitors in MEMS. Among the advantages of this approach are the sensing elements miniaturization, the absence of pull-in and squeeze damping issues typical of parallel plates, and possible aggressive duty cycles to reduce power consumption in operation.

In order to optimize the sensors design, so to make the nano-gauge linear range match the target full-scale of the quantity to sense, it is relevant to know the linearity limits of such sensing elements. This work addresses this goal through a suitably designed structure that allows measuring both the gauge nominal strength and its linearity..

 

 

   


NIRVANA Publication on JMEMS

The following paper has been accepted for publication in the Journal of Microelectromechanical Systems.

 

Analysis of mode-split operation in MEMS based on piezoresistive nano-gauges

 

Abstract—Microelectromechanical-system (MEMS) sensors based on nano-scale piezoresistive sensing elements (nano-gauges) can have mechanical modes either related only to micrometric springs or related also to nano-gauge constraints. Due to the different impact that fabrication process imperfections have on these two kinds of modes, their correlation can be poorer from part to part than in sensors based on capacitive readout. In this context, this work compares the correlation between two modes, in MEMS with and without nano-gauges. Experiments show a ± 30% relative variation in the modes difference over 26 samples of the former type, which is more than 3.5 times more than what observed on similar structures with no nano-gauges. A theoretical model identifies the sources of this fluctuation (local etching and height nonuniformities) and predicts the behavior and improvements using different springs design.

 

 

   


NIRVANA Posters at MEMS 2014

Two posters will be presented at this relevant conference, this year held in San Francisco, January 27th.

Poster 1): INVESTIGATION OF THE FATIGUE ORIGIN AND PROPAGATION IN SUBMICROMETRIC SILICON PIEZORESISTIVE LAYERS

Poster 2): ELECTROMECHANICAL DAMPING IN MEMS ACCELEROMETERS: A WAY TOWARDS SINGLE CHIP GYROMETER ACCELEROMETER CO-INTEGRATION

 

 Click the links below to download the pdf files.

 

 


General approach to dissemination activities

 

Dissemination activities will be pursued through a strategy with different levels of divulgation, according to the status of the project and to the target groups. A dissemination plan will be designed during the first six months of the project. The plan will identify:

  • the objectives: to present the project technical content, to inform about achievements enabled by new technological breakthroughs and to disseminate new knowledge in order to impact European strategies/policies in the field;
  • the activities: participation to scientific events (yearly conferences related to micro-technology, MEMS/NEMS sensors, low power electronics), publications in peer-reviewed journals (e.g. the Journal of Microelectromechanical Systems, Sensors and Actuators A, …), networking and communication with other projects and/or activities in related field;

Results of NIRVANA are expected to be of high interest for the European industry of the involved areas (consumer electronics, automotive suppliers, medical diagnostic...). The NIRVANA project will raise participation and awareness concerning micro/nano technologies and nanowires in both scientific and general public.

August - 2019
MoTuWeThFrSaSu
   1234
567891011
12131415161718
19202122232425
262728293031