Dopant and Defect Physics for Device Optimization for Hafnium Oxide based Devices

A CEA-CNRS joint laboratory, SPEC has internationally recognized expertise in photoemission based techniques in both laboratory and synchrotron environments for the understanding of functional oxides for emerging microelectronics technologies. The laboratory develops operando experiments to study the response of materials to the application of electric fields and mechanical stress. The LENSIS laboratory has a long experience in photoelectron spectroscopy using synchrotron radiation (Daresbury SLS, LURE, ESRF, ELETTRA, BESSY, SOLEIL, ANKA, SLS-Villigen, PETRA-III) and in PEEM and LEEM instrumentation. Current research themes cover ferroelectric oxides and their surface and interface chemistry in prototypical heterostructures and devices.

https://www.lensislab.com/

Devices realized with ferroelectric hafnium oxide are silicon compatible, power-efficient, and can be cost-effectively integrated into advanced technology nodes for sensor, nonvolatile memory, logic, and neuromorphic applications. Currently, hafnium-zirconium mixed oxide (Hf_xZr_1-xO₂) offers the widest stoichiometry window for fabricating ultrathin ferroelectric films with large remanent polarization. Still, the film requires oxygen vacancies to stabilize the ferroelectric phase and has reliability issues. An alternative could be to start from stoichiometric, quasi-vacancy-free hafnia and use suitable dopants to optimize the ferroelectric properties.

We will explore the influence of the dopant modulated atomic and electronic structure on the ferroelectric properties. The chosen materials will be optimized by successive simulation, processing, and characterization iterations and integrated into scaled arrays to provide statistically significant results on ferroelectric capacitor performance.

The post-doctoral research will give a better understanding of the influence of dopants on local chemistry, electronic structure, phase composition, and their effects on material and ferroelectric parameters, including recrystallization temperature and remanent polarization. The work will be done by employing a range of static and operando experiments on bare films and electrode/film interfaces (HAXPES, XPS, PFM, PEEM, XRD) in both laboratory and synchrotron environments. Operando experiments will correlate device endurance with material physical properties and electrical characterization will be carried out.

The results will be compared with ab initio calculations and will provide input for physical models based on real devices to predict key metrics such as wake-up, endurance, retention, leakage, and breakdown using vacancy-free doped hafnia.

The D3PO project is a Franco-German collaboration between the CEA, NaMLAb (Dresden) and the Technische Hochschule München, jointly funded by the ANR and the DFG.

Experimental scientist

PhD in solid state physics, surface chemistry, nanosciences

Knowledge of oxide materials, ferroelectrics

Experience in photoelectron spectroscopy preferred

Accurate studies of the physical chemsitry of doped HfO2 films