Effects of oxygen-flow rate on the characteristics of the ZrO₂ dielectric layers grown by metalorganic molecular beam epitaxy

ZrO₂ dielectric layer grown on the p-type Si substrate by MOMBE method was characterized. A large portion of the layer was composed of a polycrystalline structure. After annealing at 800°C in a N₂ ambient, the crystallinity was enhanced slightly. The crystalline structure was identified as a mixture of monoclinic and tetragonal structures. As the O₂/Ar flow ratio increased, a sharper drop at the depletion region and a flatband voltage shift in the C-V curves were observed. The calculated dielectric constant of the ZrO₂ layer was lower than the expected value and the high leakage current density was measured.