Structural and electrical properties of Al/sub 2/O/sub 3/-ZrO/sub 2/ gate dielectrics on silicon-on-insulator

Al/sub 2/O/sub 3/-ZrO/sub 2/ 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 N/sub 2/ ambient were studied by x-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The amorphous structure of the Al/sub 2/O/sub 3/-ZrO/sub 2/ film is maintained up to a post-annealing temperature of 900/spl deg/C and the expansion of the interfacial layer at high temperature is suppressed. Moreover, the current-voltage characteristic was measured with an Al/Al/sub 2/O/sub 3/-ZrO/sub 2//Si MIS structure fabricated on the films, and the result indicates excellent leakage current properties.