Growth and characterization of ultrathin zirconia dielectrics grown by ultraviolet ozone oxidation

Abstract

In this letter, we report on the growth of ultrathin films of zirconia on silicon oxide and silicon oxynitride passivated (001) Si by ultraviolet ozone oxidation of Zr metal precursor layers. The oxidation kinetics has been measured using an accelerator-based nuclear reaction analysis. It was found that oxide films up to 55 Å could be grown at room temperature by oxidation at 600 Torr while oxidation at 80 mTorr is self-limiting at 20 Å. The interfaces between the dielectric and the substrate have been characterized by scanning transmission electron microscopy. The ZrO2 films were found to be crystalline as grown. Electrical measurements on capacitor structures with 30-Å-thick ZrO2 films grown on native oxide on silicon show a capacitance–voltage hysteresis of 15 mV and a capacitance-based equivalent oxide thickness of 17 Å at 100 kHz.

Determination of Optical Properties of Thin Films from Ketteler-Helmholtz Dispersion Relations: Application to the Case of Ultraviolet Irradiated Zirconium Oxide

“…The mechanism of photon-assisted oxidation is the main hypothesis behind this part of the study. Indeed, we have chosen the wavelengths specifically in regard of their activation ability [45][46][47]. The fact that we observe the expected increase in transmittance is a strong indication that the current interpretation is truthful.…”

“…Other postdeposition processes that can be used to complete the oxidation of the films are worth being considered and could give very different outcomes. Photonassisted oxidation has been reported to improve the quality of ultrathin (few tens of nanometres) oxide films [45][46][47]. These studies indicate that the rate of oxygen incorporation is enhanced by the action of ultraviolet (UV) photons by reducing the chemical activation barriers.…”

Zirconia grown by ultraviolet ozone oxidation on germanium (100) substrates

“…6,[9][10][11][12] In this technique a thin Zr metal precursor is deposited by physical vapor deposition ͑PVD͒ on a de-ionized ͑DI͒ water-rinsed Ge substrate. Ultrahigh vacuum dc magnetron sputtering was used for these experiments.…”

“…Films of Zr metal in this thickness range have been demonstrated to become fully oxidized under the UVO conditions described above. 12 Both XPS and high-resolution TEM ͑HRTEM͒ were used to characterize the gate stacks. XPS measurements were performed with a Surface Science S-Probe instrument that utilizes monochromatized Al K␣ radiation ͑1486 eV͒.…”

Mechanism of Interstitial Oxygen Diffusion in Hafnia

“…If we consider the case where oxygen incorporates from a molecular source, we find defect energies of 1:6 eV for incorporation of atomic oxygen and 4:2 eV for molecular oxygen, favoring incorporation of two atoms over one molecule by 1 eV. However, for incorporation from an atomic source, such as in ultraviolet ozone oxidation processes (see, for example, [21]), the defect energy for atomic incorporation drops to ÿ1:3 eV, and it is now favored over molecular incorporation by almost 7 eV. In VOLUME 89, NUMBER 22 P…”