Speeding innovation for industry
Tiny variations in rotation can be detected even when vibrations are present. CEA-Leti, a CEA Tech institute, in collaboration with Politecnico di Milano (POLIMI) has made a technological breakthrough with the world's first high-performance gyroscope for harsh environments.
Motion sensors of all types are nowadays ubiquitous in everyday objects. As their use increases, so do the requirements in terms of their miniaturization, cost, performance and robustness. Gyroscopes are used for measuring rotational movements. In high-vibration environments such as those found in automotive and avionic systems, they must be able to detect a variation of less than one degree per hour—a speed of rotation around ten times slower than the Earth spins.
Gyroscopes operate at a specific resonant frequency, which poses considerable technical challenges. When this operating frequency and the frequency of vibrations in the surrounding environment are similar, the mechanical disturbances generated can distort measurements. Researchers from CEA-Leti and the POLIMI worked together to solve this problem. They developed a gyroscope that operates in the high frequency range, at around 50 kHz, beyond the parasitic vibration frequencies that sometimes occur in harsh environments.
Increasing frequency without compromising sensor performance required a technological leap that uses ultra-sensitive piezoresistive nano-gauges to replace the capacitive detection technology in MEMS gyroscopes. This new 1.5 mm2 high-frequency gyroscope, protected by multiple patents, outshines other state-of-the-art technology, not least in terms of its bias, noise and linearity specifications.
Optical microscope picture of the 50-kHz M&NEMS gyroscope (the colored areas detail the detection elements)
Main gyroscope performances 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.
The sensor is currently fabricated on CEA-Leti's silicon micro- and nanofabrication platform. It is, however, compatible with most MEMS foundries. M&NEMS technology is used in the fabrication process to integrate the gyroscope with a three-axis accelerometer and/or high-performance pressure sensor on a single chip, depending on the requirements. This work was recently presented at the IEEE SENSORS 2020 conference.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.