| AVS 66th International Symposium & Exhibition | |
| Thin Films Division | Monday Sessions |
| Session TF+EM+MI+MN+OX+PS-MoM |
| Session: | Functional Thin Films: Ferroelectric, Multiferroics, and Magnetic Materials |
| Presenter: | John Hayden, Pennsylvania State University |
| Authors: | J. Hayden, Pennsylvania State University F. Scurti, Pennsylvania State University J. Schwartz, Pennsylvania State University J.-P. Maria, Pennsylvania State University |
| Correspondent: | Click to Email |
Modern ferroelectric technologies utilize perovskite structured materials, which have limited Si compatibility and modest bandgaps requiring thick films to reduce leakage current, hindering their implementation in realizable thin film devices. HfO2 has been extensively researched as a gate dielectric thin film with excellent Si processing compatibility and has recently been found to exhibit ferroelectricity induced by a combination of impurity substitution, mechanical confinement by capping, intergranular surface area, and film thickness effects. This work investigates the microstructural characteristics, the ferroelectric response, and the potential for concomitant magnetic properties in sputtered Gd:HfO2 thin films.
Gd-substituted HfO2 thin films are a promising candidate as a multiferroic material, due to the presence of the magnetically active Gd3+ ion. Though substituting with Gd is known to induce ferroelectricity in HfO2, the magnetic properties of Gd:HfO2 have yet to be studied in depth. In this study, Gd:HfO2 films are fabricated on TaN substrates by radio frequency sputtering of a composite Gd metal and HfO2 oxide target in a mixed Ar and O2 atmosphere. Grazing incidence x-ray diffraction is used to evaluate the suppression of the paraelectric monoclinic phase and stabilization of the ferroelectric orthorhombic phase. Electrical polarization measurements are used to study the room temperature spontaneous polarization in TaN/Gd:HfO2/TaN metal-insulator-metal capacitors. Surface morphology of the films is characterized using atomic force microscopy, while magnetic properties are measured by variable temperature magnetometry. Initial magnetometry shows that Gd-substituted HfO2 exhibits remnant magnetization at room temperature.
The scalability and simplicity of Gd:HfO2, if it exhibits magnetoelectric coupling, make it an attractive model system for future developments in thin film multiferroics, having potential impacts for spintronics and other magnetoelectronic devices.