World’s First NEMS-Based Gyroscope Operates at 50 kHz, ”Beyond Frequencies Of Vibrations Common” in Severe Environments
GRENOBLE, France – Jan. 26, 2021 – CEA-Leti scientists, working with researchers at Politecnico di Milano, have developed the world’s first high-performance gyroscope for operating in severe environments, such as industrial and aeronautic equipment and automobiles. The breakthrough proves it is possible to detect minute rotational movement even among system vibrations.
Common in everyday objects, inertial sensors must be designed to meet ever-increasing constraints of miniaturization and cost, as well as requirements for performance and robustness. For certain automotive, industrial and military applications, gyroscopes must be able to detect a variation of one degree per hour, i.e. a speed of rotation about ten times slower than that of the earth, in environments that are subjected to strong, consistent vibrations.
Low-power MEMS gyroscopes are used in multiple fields because of their small footprint and low power consumption. They can monitor and control device position, orientation, direction, angular motion and rotation. Their integration into automobiles improves vehicle stability through an electronic stability-control system. They also can be used for dead reckoning – the determination of a car, ship or aircraft position without the aid of celestial observations – in driverless cars. Their integration into smartphones allows detection of unit rotation and twist (gesture-recognition functions), indoor navigation when GPS is disabled and mixed reality, among other functions.
The devices operate at a given resonant frequency. Parasitic mechanical vibrations rarely exceed 40 kHz. But today, there is no high-performance MEMS gyroscope with a resonant frequency >>20 kHz, above the frequency band of parasitic vibrations. When this frequency is close to that of the vibrations of the environment, mechanical disturbances can distort the measurements. In collaboration with Politecnico di Milano, CEA-Leti researchers overcame this distortion by developing a gyroscope that operates at frequencies in the order of 50 kHz, which is more than two times higher than the capability of conventional MEMS gyroscopes and beyond the frequencies of vibrations common even in severe automotive, industrial and aeronautic settings.
The breakthrough was reported in a paper titled “50kHz MEMS gyroscopes based on NEMS sensing with 1.3 mdps/√Hz ARW and 0.5°/h stability” at IEEE SENSORS 2020.
“While various applications are requiring improved robustness to vibrations beyond 20 kHz, state-of-the art gyroscopes are still operating around this frequency value due to a performance worsening which arises with frequency increase,” the paper reported. “This work proves that NEMS-based gyroscopes can be designed at larger operating frequencies … holding outstanding performance in terms of noise, stability and spurious modes for the considered footprint and (power) consumption.”
“To increase the gyroscope’s operating frequency without reducing sensor performance, CEA-Leti and POLIMI researchers replaced the capacitive detection of MEMS gyroscopes with ultra-sensitive piezoresistive nano-gauges,” said Philippe Robert, MEMS business development manager and senior expert at CEA-Leti. “This new 1.5 mm² high-frequency gyroscope, protected by numerous patents, has characteristics that exceed the state of the art in terms of bias, noise, linearity and other conditions.”
“I have been working on several MEMS technologies for the last 15 years, and for sure the advantages of M&NEMS technology are outstanding for several future applications”, said Giacomo Langfelder, head of the MEMS and Microsensors laboratory at the Department of Electronics, Information Technology and Bioengineering of Politecnico di Milano.
These new devices, which have been manufactured on CEA-Leti’s silicon pilot line, are compatible with processes of most MEMS foundries. Their fabrication is based on the M&NEMS technological platform that, depending on needs, allow the gyroscopes to be co-integrated with a 3-axis accelerometer and/or a high-performance pressure sensor, on a single chip.
About CEA-Leti (France)
Leti, a technology research institute at CEA, is a global leader in miniaturization technologies enabling smart, energy-efficient and secure solutions for industry. Founded in 1967, CEA-Leti pioneers micro-& nanotechnologies, tailoring differentiating applicative solutions for global companies, SMEs and startups. CEA-Leti tackles critical challenges in healthcare, energy and digital migration. From sensors to data processing and computing solutions, CEA-Leti’s multidisciplinary teams deliver solid expertise, leveraging world-class pre-industrialization facilities. With a staff of more than 1,900, a portfolio of 3,100 patents, 10,000 sq. meters of cleanroom space and a clear IP policy, the institute is based in Grenoble, France, and has offices in Silicon Valley and Tokyo. CEA-Leti has launched 65 startups and is a member of the Carnot Institutes network. Follow us on www.leti-cea.com and @CEA_Leti.
CEA has a key role in transferring scientific knowledge and innovation from research to industry. This high-level technological research is carried out in particular in electronic and integrated systems, from microscale to nanoscale. It has a wide range of industrial applications in the fields of transport, health, safety and telecommunications, contributing to the creation of high-quality and competitive products.
For more information: www.cea.fr/english
About Politecnico di Milano (Italy)
Politecnico di Milano, founded in 1863, is the leading technical university in Italy, gathering about 40000 students of Engineering, Architecture and Industrial Design. The University has always focused on the quality and innovation of its teaching and research, developing a fruitful relationship with business and productive world by means of experimental research and technological transfer. Research has always been linked to didactics and it is a priority commitment which has allowed Politecnico Milano to achieve high quality results at an international level. Research constitutes a parallel path to that formed by cooperation and alliances with the industrial system. In the field of Electrical and Electronics engineering, Politenico di Milano ranks as the 17th top university in the world.
For more information: www.polimi.it/en