Growth Characteristics and Electronic Properties of Epitaxial NdNiO₃ Thin Films by Atomic Layer Deposition

High Resolution Image Download MS PowerPoint Slide The transition to next-generation electronics is inevitable and will require innovative architectures and materials functionalities. The multifunctional and often strongly coupled behaviors of transition metal oxides can offer alternative pathways to more energy-efficient devices, such as transistors. Here, we study thin films of NdNiO 3 for its potential as a transistor channel switching material owing to the metal–insulator transition it exhibits at ∼200 K in bulk. The thin films exhibit high structural integrity and relevant functional properties when deposited by atomic layer deposition (ALD) under industrial processing conditions, thus providing a viable pathway for device integration. By varying the ratio of binary oxide subcycles, we can precisely obtain the stoichiometric NdNiO 3 composition for which the thin films become epitaxial as deposited at 225 °C on SrTiO 3 (001). Prior to annealing, the specific resistivities at room temperature show a dependence on the out-of-plane lattice parameter, c, with a nonlinear increase from 10 –4 to 10 –1 Ωcm as c increases. After annealing at 650 °C in air, both the out-of-plane lattice parameters and resistivities converge toward a narrow range ( c = 3.789–3.794 Å and 10 –4 Ωcm, respectively). X-ray diffraction and reciprocal space mapping reveal that annealing also has the effect of increasing the strain in the thin films; however, they remain partially relaxed from the substrate. A metal–insulator transition takes place at 140 K under cooling and 175 K upon heating back to room temperature.