Annealing effects on the properties of HfO_2 films grown by metalorganic molecular beam epitaxy

摘要

We present the annealing effects on the properties of HfO_2 dielectrics grown by metalorganic molecular beam epitaxy. From the comparison of the line shapes of core-level spectra for the N_2-annealed samples with different annealing temperatures, the concentrations of SiO and Hf-silicate with high dielectric constant are found to be highest for HfO_2 film annealed at 700℃. Therefore, this result supports that the accumulation capacitance of the sample annealed at 700℃ in N_2 ambient is not deteriorated in spite of the steep increase of interfacial layer thickness. For the O_2-annealed samples, SiO_2 with low dielectric constant is widely spread throughout the samples as the annealing temperature increases. Therefore, the accumulation capacitance density is degraded due to the increase in the thickness of the interfacial layer which mainly consists of SiO_2.