Properties of ZrO2 dielectric layers grown by metalorganic molecular beam epitaxy
ZrO2 dielectric layers were grown on the p-type Si (100) by metalorganic molecular beam epitaxy (MOMBE). Zirconium t-butoxide, Zr(Ot-C4H9)4 was used as a Zr precursor because of its moderate vapor pressure. The properties of the layers were evaluated by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), high resolution transmission electron microscopy (HRTEM), and capacitancevoltage (CV) and current densityvoltage (JV) analyses. Two steps in the growth, granule formation and film growth, were considered from the relation between the growth rate and the growth time. The compositional analysis confirmed the stoichiometry of the layer and typical zirconium and oxygen spectra were observed in the XPS result. RMS and average roughnesses increased due to the crystallization of the grains after the annealing treatment. HRTEM image showed that the grown layer was polycrystalline, which was closely related to the degradation of the electrical properties. From the CV and JV analyses, dielectric constant of ZrO2 layer was calculated to be 1617 and the current density was ?3.810?3 A/cm2 at a gate voltage of ?1.5 V.
zro2 metalorganic molecular beam epitaxy growth high-k dielectric thin film