Characterization of ZrO2 and (ZrO2)x(Al2O3)1−X thin films on Si substrates: effect of the Al2O3 component

ZrO2 and (ZrO2)x(Al2O3)1-x films were deposited by the sol-gel technique on Si substrates. The effect of the Al2O3 additive on the film surface morphology was studied by atomic force microscopy (AFM). The mixed oxide films showed a smoother morphology and lower values of the root-mean-square (RMS) roughness compared to ZrO2. Further, FTIR spectra indicated that ZrO2 underwent crystallization. The electrical measurements of the MIS structure revealed that the presence of Al2O3 and the amorphization affects its dielectric properties. The MIS structure with (ZrO2)x(Al2O3)1-x showed a lower fixed charge (~ 6×1010 cm−2) and an interface state density in the middle of the band gap of 6×1011 eV−1 cm−2). The dielectric constant measured was 22, with the leakage current density decreasing to 2×10−8 A cm−2 at 1×106 V cm−1.