Abstract:
This thesis investigates hafnia (hafnium oxyde: HfO₂)-based ferroelectric materials for FeFET applications, focusing on how thermal processing and interface engineering control oxygen-vacancy behavior, internal electric fields, and interfacial chemistry, key drivers of device performance and reliability.
By combining advanced photoemission spectroscopy (XPS and HAXPES), X-ray diffraction, and electrical characterization, the work builds depth-resolved correlations between defect distribution, phase stability, and ferroelectric response in technologically relevant MFIS stacks. The results show that thicker interlayers improve electrical properties, while high-temperature annealing increases oxygen vacancy concentration. HAXPES highlights the role of buried interfaces as reservoirs and pathways for defect redistribution, directly impacting imprint and switching stability.
Conducted within a CIFRE collaboration with STMicroelectronics, this work provides predictive guidelines to reduce variability and improve endurance in CMOS-compatible FeFETs toward industrial deployment.
Keywords: Interface engineering, X-ray diffraction, Non-volatile memory, Oxygen vacancies, Electrical characterization, Photoemission spectroscopy (XPS and HAXPES), FeFET, HfO₂, Ferroelectricity.