Low Power Image Sensor for Distributed Processing in Cameras Network
Working in a collaborative academic project, your task will be to develop a smart image sensor for a wireless camera network embedding distributed AI computing.
Current camera network contains several standard cameras that transmit their images to a global server performing the targeted inference processing. This kind of architecture proposes energy and frugality performances that are not compatible with IoT requirements.
The project goal is to tackle hardware frugality through a distributed and collaborative approach based on ultra-low-power computing nodes. Each node’s inference core will be built around ASIC processors performing calculations in analog form. The final demonstrator will consist of a wireless network of “motes” (sensor network nodes) integrating dedicated image sensors paired with hybrid processors performing analog processing.
In this context, the mote’s image sensor must extract strategic features with frugality and efficiency which implies that you have to define, design and test an innovative readout architecture of a standard imager. In collaboration with the academic partners, you will be involved in the definition of the overall mote architecture allowing to define basically the output data format and the output procedure of the imager including potential pre-processing for the distributed inference computations. The studied architecture will integrate innovative low power solutions to address the targeted IoT applications and perform both image acquisitions and AI pre-processing.
As an image sensor demonstrator is planned in this PhD Thesis, the work will be conducted at CEA-Leti in the L3i Laboratory, using professional IC design tools and software development environments.
LLM-Assisted Generation of Functional and Formal Hardware Models
Modern hardware systems, such as RISC-V processors and hardware accelerators, rely on functional simulators and formal verification models to ensure correct, reliable, and secure operation. Today, these models are mostly developed manually from design specifications, which is time-consuming and increasingly difficult as hardware architectures become more complex.
This PhD proposes to explore how Large Language Models (LLMs) can be used to assist the automatic generation of functional and formal hardware models from design specifications. The work will focus on defining a methodology that produces consistent and executable models while increasing confidence in their correctness. To achieve this, the approach will combine LLM-based generation with feedback from simulation and formal verification tools, possibly using reinforcement learning to refine the generation process.
The expected outcomes include a significant reduction in manual modeling effort, improved consistency between functional and formal models, and experimental validation on realistic hardware case studies, particularly RISC-V architectures and hardware accelerators.
Self-healing of radiation-induced defects in silicon solar cells for space
Over the last decades, the development of alternative space photovoltaic (PV) solutions to the III-V premium standard has shifted the focus to silicon solar cells. Indeed, leveraging on existing maturity of terrestrial PV silicon devices and processes offers significant potential for innovation and cost reduction. Many satellites nowadays evolve in Low Earth Orbit, a proton and electron rich environment. Such irradiations induce electrically active defects in the material which affect the PV performances. Interestingly, some of the irradiation-induced defects can be healed upon external factors such as temperature and/or photons flux.
The main goals of this PhD thesis will be to i) understand the bulk & interface electron/proton irradiation-induced degradation mechanisms driving the evolution of the optoelectronic properties of silicon passivated contacts solar cells ii) develop a comprehensive understanding of the self-healing effects in irradiated modern silicon solar cells through experimental studies and modeling iii) identify design / fabrication process routes to control & boost the self-healing capability.
To reach these goals, this PhD work will go through defined steps: bibliography review, solar cells fabrication, material/device ageing under proton & electron irradiations, advanced characterizations and modeling. This PhD work will be conducted at CEA/Liten, on the INES campus (Le Bourget du Lac, FR) with frequent interactions with CNES (Toulouse, FR) facilities.
Sustainable development of digital circuits and systems: Taking planetary boundaries into account
Technological developments in the electronics sector are experiencing rapid growth, accompanied by increasing interest in accounting for their environmental impacts. However, current approaches remain largely focused on relative impact reductions (energy efficiency, resource optimization), without ensuring compatibility with planetary boundaries. In this context, the concept of absolute sustainability emerges as an essential framework for guiding future developments of electronic systems.
This PhD thesis addresses several major scientific challenges: how can carrying capacities and sharing principles (core concepts of absolute sustainability) be identified for the electronics sector and consistently translated down to the levels of digital systems and integrated circuits? How can planetary boundaries be concretely integrated into the design of systems and circuits?
The main objective of the thesis is to move from a logic of relative environmental impact reduction toward designs that are compatible with planetary boundaries. It aims to define socio-technical scenarios to identify sharing principles, to conduct the first absolute life cycle assessment of a digital system, and to propose the first design of a circuit based on absolute limits, paving the way for sustainable development in electronics.
Topologically Isolated Mode Acoustic Resonators
Timing is a key function in electronic circuits. Beyond on-chip signals synchronization, it also allows the synchronization of wireless data transmissions. Accurate time references require stable frequency sources, which also benefit to sensor applications. The gold standard for time or frequency generation is still quartz resonators, which are however bulky and difficult to miniaturize. Research is therefore still ongoing to provide high quality factor (> 10,000) resonators, ideally capable of operating at frequencies of several GHz. A key to reach such high quality factors is to confine strongly the mechanical vibration of micro-size structures in order to make them insensitive to external perturbations. Recently, the field of topological acoustics has demonstrated the capability to confine elastic waves in very small volumes concentrated at the interface between periodic structure, and to provide extremely high quality factor resonances.
This PhD position focuses on exploiting topologically protected modes in piezoelectric microstructures to provide next generations of high quality factor resonators, which may be used in oscillators or even filter circuits. Leveraging the know-how of CEA Leti in the design and fabrication of such components, the PhD will be part of an international collaboration with well established academic laboratories (Politecnico di Milano, Imperial College FEMTO-ST Institute) and industrial partners.
The candidate will model and design structures supporting topologically protected modes, combinining finite element simulations with simplified numerical approaches which reduce computation times. He will follow the fabrication of demonstrators in collaboration with the process integration teams in the CEA Leti clean rooms, and carry on measurements of the proposed resonators.
SiGe HBT LNA for cryogenic applications: design, characterization and optimization
The global race to build a quantum computer is heating up! These cutting-edge systems operate at temperatures below 4 K to preserve the delicate quantum states essential for computation. To achieve efficient control and detection, conventional electronic circuits must perform reliably at cryogenic temperatures, in close proximity to the quantum processor, thereby reducing wiring complexity and boosting performance. Beyond quantum computing, other domains—such as space exploration, high-performance computing, or high-energy physics—also require transistors capable of operating below 100 K.
During this phD, you will perform radiofrequency (RF) electrical characterization and modeling of Silicon-Germanium Heterojunction Bipolar Transistors in cryogenic environment, contributing to a deeper understanding of their behavior and optimizing their potential for extreme-condition applications. The objectives are twofold:
1.RF Electrical Characterization and Modeling:
•Conduct RF electrical measurements of SiGe HBTs at cryogenic temperatures.
•Develop accurate models to describe their behavior in cryogenic environments.
2.Optimization of Low-Noise Amplifiers (LNAs):
•Study the low-temperature behavior of individual passive and active devices composing an LNA.
•Optimize the design of low-noise amplifiers (LNAs) for cryogenic applications.
Study of Failure Modes and Mechanisms in RF Switches Based on Phase-Change Materials
Switches based on phase change materials (PCM) demonstrate excellent RF performance (FOM <10fs) and can be co-integrated into the BEOL of CMOS processes. However, their reliability is still very little studied today. Failure modes such as heater breakage, segregation, or the appearance of cavities in the material are shown during endurance tests, but the mechanisms of these failures are not discussed. The objective of this thesis will therefore be to study the failure modes and mechanisms for different operating conditions (endurance, hold, power). The analysis will be carried out through electrical and physical characterizations and accelerated aging methods will be implemented.
Superconducting Silicon and detection in the far Infrared Universe
Silicon technologies occupy a central position in today’s digital landscape, both for the fabrication of semiconductor devices and for the development of advanced sensors. In 2006, the discovery of superconductivity in silicon heavily doped with boron opened a new field of research. Since then, several laboratories, including CEA, have been investigating its electronic properties and potential applications. This emerging material exhibits particularly attractive characteristics for systems operating at sub-Kelvin cryogenic temperatures, especially in the fields of quantum electronics and ultra-sensitive detectors used in fundamental physics and astrophysics.
Despite these advances, the understanding of superconducting silicon remains incomplete, particularly regarding its thermal, mechanical, and optical properties at the micrometric scale. The proposed PhD aims to address these gaps by combining modelling, design, technological fabrication, and cryogenic characterization of prototype devices, within a close collaboration between CEA-Léti and CEA-Irfu. The main objective will be to develop a new generation of detectors based on this superconducting material and to demonstrate their relevance for the detection of electromagnetic radiation in the terahertz and far-infrared ranges.
Reinventing Microspeakers: From Planar Limits to 3D Designs for Ultrasonic Modulation Loudspeakers
Are you looking for a PhD at the intersection of acoustics, microsystems, and innovation? This project may be for you.This PhD focuses on the design, fabrication, and experimental validation of an innovative MEMS microspeaker concept based on ultrasound demodulation. Conventional micro transducers face a major limitation: they require large planar surfaces to displace sufficient air at low frequencies, leading to increased device size and manufacturing cost. This project explores an alternative architecture using vertical blade structures, exploiting the third dimension together with ultrasound demodulation to improve electro acoustic efficiency while reducing device footprint.
Building on preliminary exploratory work, the objective of the PhD is to develop a complete MEMS loudspeaker demonstrator. The work will include physical modeling, multi-physics simulation, device design optimization, microfabrication process development, and experimental electro acoustic characterization. Particular attention will be given to identifying and overcoming the physical and technological limitations governing device performance.
The candidate will design and simulate the device architecture and contribute to the definition of the fabrication process in close interaction with microfabrication specialists. The PhD work will also include acoustic and electrical characterization of the fabricated devices in order to validate the proposed concepts and compare experimental results with modeling predictions. The PhD will take place in a multidisciplinary environment, providing access to expertise in acoustics, MEMS design, microfabrication processes, and electro acoustic measurement.