Growth of HfO2/TiO2 nanolaminates by atomic layer deposition and HfO2-TiO2 by atomic partial layer deposition

Abstract

A novel growth technique, called atomic partial layer deposition (APLD), has been proposed to expand the applications of, and the research in, atomic layer deposition (ALD). This technique allows the possibility for the fabrication of well-controlled alloys on a single atomic layer scale. To demonstrate the capabilities of this technique, samples of HfO2 and TiO2 were prepared as conventional ALD nanolaminates through the repeated exposure of the separated metal-precursor and reactant. Subsequently, HfO2-TiO2 APLD growth mode samples were obtained by varying the precursor doses and exposure times to obtain a fractional coverage in the monolayer of Hf and Ti. The thickness and structure of the samples were studied by X-ray reflectivity. The surface topography was studied using atomic force microscopy along with Kelvin probe force microscopy for surface potential mapping. Clear differences on the surface, compared with the conventional HfO2/TiO2 ALD nanolaminates, were observed, which confirmed the HfO2-TiO2 APLD growth. The films were analyzed using X-ray photoelectron spectroscopy (XPS) depth profile scans and angle resolved XPS, where well-defined HfO2 and TiO2 contributions were found for both the conventional and APLD mode samples, and an additional contribution, assigned to a ternary phase Hf-Ti-O, in the APLD grown films was observed. This result confirms that Hf and Ti form an alloy in a monolayer by APLD mode growth.

The Bright X‐Ray Stimulated Luminescence of HfO2 Nanocrystals Activated by Ti Ions

“…The titanium spectrum of the 1% doped HfO 2 :Ti NPs before calcination exhibits two components: one at 459.2 eV and another less intense one at 457.00 eV, assigned to Ti (IV) and Ti (III) in their corresponding oxides. These values are in agreement with those reported in the literature . It is worth noting that the peak at lower binding energy might be influenced by the presence of the Hf4p signal that is usually revealed at 454.3 eV.…”

Activation of Zr, ZrVHf and TiZrV Non-Evaporative Getters Characterized by In Situ Synchrotron Radiation Photoemission Spectroscopy

“…Figure 4 shows SRPES spectra of the V 2p, Ti 2p and Hf 4f core-level peaks of ZrVHf and TiZrV films recorded after heating at various temperatures. The peak position resolved in Figure 4 is consistent with references [31][32][33]. In Figure 4a-c, the reduction in the fully oxidized states of V 2p and Ti 2p in ZrVHf and TiZrV films occurred after heating at a temperature of only 120 • C.…”

Enhancing Short-Term Plasticity by Inserting a Thin TiO2 Layer in WOx-Based Resistive Switching Memory

“…Figure 1a-c show the XPS spectra of Ti 2p, W 4f, and Pt 4f, respectively, at different depths. For the Ti 2p core level spectra on the surface before etching, the binding energies of two peaks are centered at 459.2 and 465 eV, corresponding to Ti 2p 3/2 and Ti 2p 1/2 in Figure 1a [39]. This indicates that the ALD TiO 2 layer is close to the appropriate stoichiometry.…”