Ferroelectric Materials for Electron Devices: The Crucial Role of Material Compatibility with Highly Developed Fabrication Processes

Ferroelectricity is a material property that consists of a switchable, non-zero polarization without applied electric file. It is a rare material property that exists only in certain no-centrosymmetric crystals. However, ferroelectricity opens up a large number of exiting possibilities in electron devices since it combines nonvolatility with a low power switching operation. Unfortunately, typical ferroelectric materials like lead zirconium titanate (PZT) or strontium bismuth tantalate (SBT) having the perovskite or layered perovskite structure are very difficult to integrate into state-of-the-art electronic processes. Therefore, integrated devices utilizing ferroelectricity have stopped scaling around the 90nm technology node and are therefore limited to niche applications. The discovery of ferroelectricity in the binary oxide HfO₂ doped with dopants like Si, Al, Y, etc. or mixed with its sister oxide ZrO₂ has therefore attracted an incredible interest from both research communities and the semiconductor industry. This talk will start with a short history of ferroelectric applications in electron devices, mainly ferroelectric memories, explaining the difficulties that arise when integrating PZT or SBT into an electronic device process. It will then introduce newly discovered, semiconductor compatible ferroelectrics with a focus on fluorite structured hafnia-based ferroelectrics and some outlook towards wurtzite structured ferroelectrics like AlScN. Finally, the state of the art in memory devices, non-von Neumann computing and selected other applications will be highlighted showing some interesting device applications.