Atomic Layer Deposition of hexagonal ErFeO₃ thin films on SiO₂/Si

Hexagonal orthoferrite h-ErFeO₃ thin films are synthesized by Atomic Layer Deposition on SiO₂(100 nm)/Si substrate, followed by rapid thermal annealing at 650–700 °C. Structural, chemical and morphological characterizations of as-deposited and annealed layers are performed by X-ray Reflectivity/Diffraction and Time-of-Flight Secondary Ion-Mass Spectrometry. The formation of the hexagonal phase, which is metastable compared to the more stable orthorhombic ErFeO₃, is explained within a simple model considering the different activation energies for the nucleation of hexagonal and orthorhombic phases. The possibility to grow h-ErFeO₃ in contact with SiO₂/Si by chemical methods opens perspective for the inclusion of new multiferroics in silicon-based devices. - Highlights: • Thin films of ternary alloy ErFeO₃ are synthesized by Atomic Layer Deposition. • The as deposited films are amorphous and crystallize with annealing at 650–700 °C. • X-ray diffraction measurements show the formation of metastable hexagonal phase. • The formation of metastable phase is explained within a simplified model. • The model considers activation energies as a function of the supplied thermal budget.