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Internship positions below
contact : nick.barrett@cea.fr
contact : lucia.perezramirez@cea.fr
Open internship position
Title : Local control and imaging of ferroelectric domains in HfZrO2 layers using piezoelectric force (PFM) and electron microscopy (LEEM-PEEM) techniques
Domain, Specialties: Material physics, surface science
Keywords: Surfaces, interfaces, imaging, microscopy, PFM, LEEM, PEEM
Location: CEA Saclay, France
Type of contract: Internship
Summary: This internship focuses on the characterization of ferroelectric (FE) domains in hafnium zirconium oxide (HZO) films. We propose to train the student to use several surface imaging techniques (piezoelectric force microscopy, PFM, low energy electron microscopy, LEEM, and x-ray photoemission electron microscopy, PEEM) for this purpose. The results from this study will allow understanding the effects of the metal electrode/FE layer interface in the polarization switching mechanisms.
Full description
Ferroelectric materials are characterized by the presence of a spontaneous polarization, whose orientation can be reversed by the application of an external electric field. This property finds an important application in information technologies, notably in non-volatile memories (NVM) where information can be encoded in the form of a ferroelectric domain, i.e. a region of the material with a certain orientation of the polarization (P or P¯) corresponds to an information state (1 or 0).
Currently, hafnium zirconium oxide (HfZrO2) is the most promising material for NVM fabrication thanks to its proven compatibility with standard CMOS processes and very low power consumption. HZO paves the way for very high-density mass storage (>10 Tbit/in²) because it retains its ferroelectric properties at very low layer thicknesses (< 10 nm), which allows more polarized domains per unit area.
The size of a domain in a HZO ferroelectric layer is about a few nm, which makes their study complex. We propose to use piezoelectric force microscopy (PFM) to examine them, due to its nanometric resolution and high sensitivity. We will use a particular mode of the technique that allows local writing of the domains and their subsequent imaging. This will allow us to study the phenomena of charge injection and polarization switching. In parallel, the student will use Low-Energy Electron Microscopy (LEEM) and PhotoEmission Electron Microscopy (PEEM) to characterize the surface potential, an inherent property of the material. We expect to elucidate the influence of the presence (absence) of a metal electrode above the ferroelectric layer in the mentioned electrostatic mechanisms.
Internship conditions
Internship duration: 5-6 months
Level of study: Bac+4/5
Training: Ingenieur/Master
Continuation in PhD thesis: Yes
Application deadline: 30 november 2024
Experimental skills
Useful methods and technics:
Piezoelectric force microscopy (PFM)
Low-Energy Electron Microscopy (LEEM)
X-ray photoemission electron microscopy (PEEM)
How to apply
Candidates should send a CV and a cover letter to the e-mail addresses in the contact information.
Links: iramis.cea.fr/spec/lensis
Contact
Tutor
Lucia PEREZ RAMIREZ
Phone: 01 69 08 47 27
Email: lucia.perezramirez@cea.fr
Head of the laboratory
Nick BARRETT
Phone: 01 69 08 32 72
Email: nick.barrett@cea.fr