In recent years, there has been a renewed interest in ferroelectrics in low power integrated electronics such as memory. The discovery of ferroelectric hafnia has led to further scaling of layers to sub 10 nm thicknesses. However, the multiphasic nature of hafnia yields poor endurance and across-wafer repeatability. Complex oxides such as perovskites offer a an extremely flexible structure class of materials that offer a wide variety of ferroelectrics with tunable dielectric properties. However, dead-layer effects, negative conduction band offsets with Si, and complex stoichiometries, make the integration and scaling of these materials challenging on devices in large wafer production. Ferroelectricity has been observed in ultrathin films in epitaxy but polycrystalline films, which are preferred in production, have yet to be demonstrated.
The development of complex oxide-based materials will be undertaken targeting ferroelectricity in ultrathin layers for devices. Pulsed laser deposition (PLD) will be used on 200mm wafer scale to deposit and optimise complex oxide, perovskite-based materials. Interfacial and strain engineering will be used to minimise dead-layers, and other phenomena that could negatively effect ferroelectricity in these layers. Understanding the growth, structural mechanisms, the role of strain and interfacial chemistries on the ferroelectric response will be key to building a knowledge library and proof-of-concept for the operation of ultrathin ferroelectric complex oxides.
The candidate should have a Master's degree in physics, chemistry, materials, or related subject. Experience in thin film growth and/or complex oxides is a plus. The chosen candidate will be able to work both independently and as part of a team, will be enthusiastic and driven, and will be comfortable with presenting their work in front of their peers.
Required background: Chemistry, Physics, Engineering Science or equivalent
Type of work: 90% experimental 10% simulation
Supervisor: Ingrid De Wolf
Daily advisor: Sean McMitchell, Christoph Adelmann
The reference code for this position is 2020-020. Mention this reference code on your application form.