Structural and electrical properties of Al2O3-ZrO2 gate dielectrics on silicon-on-insulator

Al₂O₃-ZrO₂ composite films were prepared on silicon-on-insulator (SOI) substrate by ultra-high vacuum electron-beam co-evaporation. The crystallization temperature, microstructures and surface morphology of the films during high temperature rapid thermal annealing (RTA) in N₂ ambient were studied by x-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The amorphous structure of the Al₂O₃-ZrO₂ film is maintained up to a post-annealing temperature of 900°C and the expansion of the interfacial layer at high temperature is suppressed. Moreover, the current-voltage characteristic was measured with an Al/Al₂O₃-ZrO₂/Si MIS structure fabricated on the films, and the result indicates excellent leakage current properties.