We are looking for highly motivated candidates to work on our projects

PhD and Post-doc positions below

contact : nick.barrett@cea.fr

Post-doctoral positions

• ECHOES : Edge seCurity witH ferrOelectric dEviceS

Data centric applications such as artificial intelligence and IoT require to process a massive amount of Data. The energy overhead of data transfer to and from the cloud will rapidly become unbearable. To meet this challenge, edge computing is necessary. However, this also means that sensitive data may be stored and processed outside of traditional data centers, which can potentially expose it to security threats thus putting a strong emphasis on securing data in edge computing. In this context, emerging non-volatile memory technologies are potential candidates for secured NVM in future edge-devices thanks to their superior scalability and energy-efficiency as compared to Flash. Ferroelectric hafnia-based NVM are highly appealing because of their ultra-low power consumption (< 0.1pJ/bit)[4], high endurance (>1014) and the intrinsic stochasticity.

The goal of ECHOES is to determine whether hafnia-based FE NVM can outperform current NVM solutions for edge-security applications bring a comprehensive understanding of imprint through advanced characterization and physical modelling.

In particular, we will investigate the materials physics of hafnia-based capacitors which allow to minimize the hysteresis imprint via control of the oxygen vacancy distribution and the insertion of appropriate interface layers and thus maximize the hardware security.

Ferroelectric capacitors stacks will made at INL by physical vapor and atomic layer deposition (PVD and ALD). Advanced structural and electrical characterization on samples will provide crucial insights to feed and/or confirm the physical model

The post-doctoral research will use X-ray Photoelectron Spectroscopy (XPS, HAXPES) and PhotoEmission Electron Microscopy (XPEEM) to characterize the oxygen vacancy profiles near the electrode/ferroelectric interface and the interface chemistry and electronic structure in FeCAP test structures as a function of cycling. The intensive use of hard X-rays will allow analyzing devices with realistic top electrode thicknesses at synchrotron radiation centers in operando conditions using dedicated sample-holders. Microscopic FeCAPs will be characterized using both laboratory and synchrotron based XPEEM. Stochastic switching on sub micron test structures, fabricated by e-beam lithography on the NanoLyon platform of INL will be investigated by Piezoresponse Force Microscopy (PFM) at SPEC.

Partners

Institut des Nanotechnologies de Lyon (INL)

Institut Materials Microelectronic and Nanoscience of Provence (IM2NP)

Service de Physique de l’état condense au CEA (SPEC)

The post-doc contract is for 20 months, start date early 2026 preferred.

CV and contact details for two references before 16th October 2025 to Nick Barrett (nick.barrett@cea.fr)

• Ferrofutures : “plateForme fERROélectrique pour le calcUl embarqué critique : efficaciTé, peRformancES, adaptibilité

FerroFutures aims to demonstrate all of the scientific and technical elements required for the value chain of a future French ferroelectronics branch capable of responding to the needs of artificial intelligence at the edge.

Amongst emerging memory and logic technologies, ferroelectrics offer by far the best energy consumption, allowing access to low-cost non-volatile functionalities, several orders of magnitude more frugal than competitors.

FerroFutures will integrate this emergent techonology with innovative circuit and systems architectures for edge AI.

The post-doctoral research is an integral part of the optimization of a FeMFET, i.e. a ferroelectric capacitor (FeCAP) wired to the gate of a standard CMOS transistor. The FeCAP should show with low operating voltage, endurance better than 1012 cycles, non-destructive read, zero imprint.

The FeCAPs will be elaborated by physical vapor and atomic layer deposition (PVD and ALD). Structural characterization by X-ray diffraction and by atomic force microscopy will analyze the phase composition and grain size of the hafnia based films. The macroscopic electrical properties of the FeCAPs will be extracted from I-V, C-V and PUND measurements. Piezo-response force microscopy will provide information on the microscopic scale. The FeCAPs will then be studied using X-ray photoelectron spectroscopy (XPS) in the laboratory and by Hard X-ray photoemission (HAXPES) using synchrotron radiation. The latter will allow operando experiments to quantify the oxygen vacancy distribution as a function of endurance and polarization. Several synchrotrons will be used, including Soleil, Petra-III (Hamburg), Spring-8 (Japan) and NSLS-2 (Brookhaven, USA). The results will form an ensemble of physical characteristics to validate the fabrication processes and to provide experimental input to the modelling.

Partners

L’Université de Bordeaux (IMS)

Institut Materials Microelectronic and Nanoscience of Provence (IM2NP)

Institut des Nanotechnologies de Lyon (INL)

CEA/LETI

CEA/LIST

CEA IRAMIS (Service de Physique de l’état condense SPEC)

CV and contact details for two references before 31st July 2024 to Nick Barrett (nick.barrett@cea.fr)

To cope with the requirements of Artificial intelligence at the edge, new architectures have to be explored in the light of new emerging devices technologies. In the context of the Horizon Europe Ferro4EdgeAI collaborative project, we aims to develop and demonstrate from 1000X to 2500X energy efficiency gain with respect to cloud based CMOS for intelligent edge processors based on ferroelectric technology and the computation-in-memory paradigm.

The unique characteristics of FE technology [Silva2023] will be explored in the light of the targeted applications. The device technology at the heart of Ferro4EdgeAI is the FeFET-2 in which a ferroelectric capacitor is added in series with the gate stack of a conventional CMOS transistor (Figure). Conceptually this combines the simplicity and endurance/retention characteristics of the FeRAM with the plasticity and quasi-analogue response of the FeFET, without the adverse effects of charge trapping on endurance, retention, imprint and drift.

The primary objective of the materials aspect of Ferro4EdgeAI is the optimization of HfO2-based ferroelectric materials for multilevel functionality suitable for AI applications by investigating the trade-off in memory window, film thickness & stability of the ferroelectric state. We require a FE film which offers the possibility for a large memory window (large remanent polarization), able to retain the set polarization states.

The post-doctoral research will focus on the switching kinetics of films with different process parameters and switching voltages will be analysed via time-resolved X-ray photoemission spectroscopy (XPS, PEEM) with a time-resolved detector funded by the project to characterize ML switching.

Extensive use of synchrotron radiation is foreseen for the operando experiments. Samples will be supplied by NaMLab (Dresden) and the CEA LETI (Grenoble) who will also provide the integration.

In addition to the scientific research, the successful candidate will be expected to assist in project management and interact with all of the consortium partners, in particular for reporting and organization of regular project meetings.

The initial contract is for 22 months, June 2024 start date, negotiable

CV and contact details for two references before 31st March 2024 to Nick Barrett (nick.barrett@cea.fr)

[Silva2023] J.P.B. Silva et al, Roadmap on ferroelectric hafnia-and zirconia-based materials and devices APL Mater. 11, 089201 (2023)

[Vianello2019] Vianello, E., L. Perniola, and B. De Salvo. Emerging memory technologies for neuromorphic hardware Advances in Non-Volatile Memory and Storage Technology. Woodhead Publishing 585 (2019)

[Mulaosmanovic2018] H. Mulaosmanovic et al., Accumulative Polarization Reversal in Nanoscale Ferroelectric Transistors ACS Appl. Mater. Interfaces 10, 23997 (2018)