The investigations on the properties of HfO2 dielectric layers grown by metalorganic molecular beam epitaxy were performed. Hafnium-tetra-tert-butoxide. Hf(C4H9O)(4) was used as a Hf precursor and pure oxygen was introduced to form an oxide layer. The grown film was characterized by X-ray photoelectron spectroscopy (XPS). atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), and capacitance-voltage (C-V) and current-voltage (I-V) analyses. As an experimental variable, the 0, flow rate was changed from 2 to 8 scent while the other experimental conditions; were fixed. The XPS spectra of Hf 4f and O 1s shifted to the higher binding energy due to the charge transfer effect and the density of trapped charges in the inter-facial layer was increased as the oxygen flow rate increased. The observed microstrucrure indicated the HfO2 layer was polycrystalline, and the monoclinic phases are the dominant crystal structure. From the C-V analyses, k = 14-16 and EOT = 44-52 were obtained, and the current densities of (3.2-3.3) x 10-(5) A/cm(2) were measured at -1.5 V gate voltage from the I-V analyses. (C) 2004 Elsevier B.V. All rights reserved.