Low through-plane thermal conductivity in amorphous HfO2/SiO2 nanolaminates

Accurate knowledge of thermal transport in amorphous oxides is essential for effective thermal management in advanced semiconductor and cryogenic electronic devices. In this work, we investigate the through-plane thermal conductivity (κz) of amorphous HfO2/SiO2 nanolaminates fabricated by atomic layer deposition across the temperature range from 30 to 315 K. These multilayers serve as a model system for studying heat transport in amorphous thin films, where interfacial effects may significantly influence thermal conduction. Thermal conductivities were determined using the differential 3ω method and analyzed within the framework of the heat equation. A composite model combining the minimum thermal conductivity approach for the individual amorphous layers with the diffuse mismatch model for interfacial effects quantitatively reproduces the experimental data. The multilayers exhibit low thermal conductivities of 0.77±0.08 and 0.050±0.0015Wm−1K−1 at 300 and 30 K, respectively.