Effect of Al₂O₃ Buffer Layers on the Properties of Sputtered VO₂ Thin Films

VO₂ thin films were grown on silicon substrates using Al₂O₃ thin films as the buffer layers. Compared with direct deposition on silicon, VO₂ thin films deposited on Al₂O₃ buffer layers experience a significant improvement in their microstructures and physical properties. By optimizing the growth conditions, the resistance of VO₂ thin films can change by four orders of magnitude with a reduced thermal hysteresis of 4 °C at the phase transition temperature. The electrically driven phase transformation was measured in Pt/Si/Al₂O₃/VO₂/Au heterostructures. The introduction of a buffer layer reduces the leakage current and Joule heating during electrically driven phase transitions. The C-V measurement result indicates that the phase transformation of VO₂ thin films can be induced by an electrical field.