Orthorhombic crystal system

Oxide

Materials science

Chromatography

Ceramic

Hafnia

Dopant

Crystal structure

Inorganic chemistry

Ferroelectricity

Physical chemistry

Polarization (electrochemistry)

Lanthanum

Organic chemistry

Dielectric

Hafnium

Doping

Zirconium

Analytical Chemistry (journal)

Crystallography

Chemistry

Cubic zirconia

Lanthanide

Optoelectronics

Inorganic Chemistry

Recently simulation groups have reported the lanthanide series elements as the dopants that have the strongest effect on the stabilization of the ferroelectric non-centrosymmetric orthorhombic phase in hafnium oxide. This finding confirms experimental results for lanthanum and gadolinium showing the highest remanent polarization values of all hafnia-based ferroelectric films until now. However, no comprehensive overview that links structural properties to the electrical performance of the films in detail is available for lanthanide-doped hafnia. La:HfO2 appears to be a material with a broad window of process parameters, and accordingly, by optimization of the La content in the layer, it is possible to improve the performance of the material significantly. Variations of the La concentration leads to changes in the crystallographic structure in the bulk of the films and at the interfaces to the electrode materials, which impacts the spontaneous polarization, internal bias fields, and with this the field cycling behavior of the capacitor structure. Characterization results are compared to other dopants like Si, Al, and Gd to validate the advantages of the material in applications such as semiconductor memory devices.

Lanthanum-Doped Hafnium Oxide: A Robust Ferroelectric Material