Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PostDocs : selection by topics

Technological challenges >> Cyber physical systems - sensors and actuators
3 proposition(s).

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Design of innovative time-domain microphone readout using Injection Locked Oscillators

Département Composants Silicium (LETI)

Laboratoire Gestion de l'Energie, Capteurs et Actionneurs

01-01-2020

PsD-DRT-20-0023

franck.badets@cea.fr

Nowadays, Voice Activity Detection is a hot research topic. This application needs the design of high linearity, high dynamic ( > 100 dBSpl) and low noise (< 25 dBSpl) microphones putting stringent requirement on both the transducer and the readout electonics. State of the art microphone readouts are based on a classical amplifier and sigma delta conversion. They fulfill the needs in term of dynamic and noise but at the expense of a high power consumption (1 mW) not compliant with mobile applications. CEA-LETI is currently working on an innovative transducer design that fulfills the needs in terms of dynamic and noise. To go along with the transducer development, CEA-LETI is searching for a PostDoc whose mission will be to study an Ultra Low Power architecture of readout circuits working in the time-domain and based on Injection Locked Oscillators. The post doc work will consist in an architecture study and its evaluation in term of expected performances. In a second time an optimized chip should be designed and fabricated. Evaluation of the solution will be made by a thorough measurement of the test chip.

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Nano-optomechanical silicon accelerometer for high performance applications

Département Composants Silicium (LETI)

Laboratoire Composants Micro-Capteurs

01-06-2020

PsD-DRT-20-0035

sebastien.hentz@cea.fr

Inertial sensors (accelerometers and gyrometers) are at the heart of a large number of consumer-and low-cost applications such as smartphones and tablets, but also higher added value, higher-performance applications such as navigation for autonomous vehicles, aeronautics or space. Silicon microsystems (MEMS) are today a very mature technology and several millions are sold each year. However, they are today unable to address high-performance applications. LETI has been pioneering the development of optomechanical sensors "on-chip": light is guided in thin silicon layers in a similar way to photonics techniques. This light interacts with an object in motion such as a mechanical resonator or a seismic mass. This displacement modulates the intensity of the measured light, which allows the determination of the object's acceleration. This technology was developed in the 2000s in fundamental research, and in particular enabled gravitational wave detectors. LETI is developing this technology on-chip at the nanoscale, with displacement sensitivities several orders of magnitude better than electrical transductions. First optomechanical accelerometers were designed and fabricated in LETI's quasi-industrial clean rooms for initial characterization tests. The hired fellow with have to become familiar with these devices, to confirm the first optical results, and then most importantly to assess their performances under acceleration: a test setup will have to be realized for this purpose. She or he will have to provide feedback on the modeling and the design from the measurements in order to ensure the comprehension of all phenomena at play. Finally, the postdoctoral fellow will have to propose new designs aimed at the expected high performances. These devices will be fabricated by the clean room, tested by the fellow and and compared to the expected performance.

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Non-volatile asynchronous magnetic SRAM design

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Intégration Silicium des Architectures Numériques

01-10-2020

PsD-DRT-20-0069

jean-frederic.christmann@cea.fr

In the applicative context of sensor nodes as in Internet of things (IoT) and for Cyber Physical Systems (CPS), normally-off systems are mainly in a sleeping state while waiting events such as timer alarms, sensor threshold crossing, RF or also energetic environment variations to wake up. To reduce power consumption or due to missing energy, the system may power off most of its components while sleeping. To maintain coherent information in memory, we aim at developing an embedded non-volatile memory component. Magnetic technologies are promising candidates to reach both low power consumption and high speed. Moreover, due to transient behavior, switching from sleeping to running state back and forth, asynchronous logic is a natural candidate for digital logic implementation. The position is thus targeting the design of an asynchronous magnetic SRAM in a 28nm technology process. The memory component will be developed down to layout view in order to precisely characterize power and timing performances and allow integration with an asynchronous processor. Designing such a component beyond current state of the art will allow substantial breakthrough in the field of autonomous systems.

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