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Title: Enhanced resistive switching and multilevel behavior in bilayered HfAlO/HfAlO{sub x} structures for non-volatile memory applications

In this work, hafnium aluminum oxide (HfAlO) thin films were deposited by ion beam sputtering deposition technique on Si substrate. The presence of oxygen vacancies in the HfAlO{sub x} layer deposited in oxygen deficient environment is evidenced from the photoluminescence spectra. Furthermore, HfAlO(oxygen rich)/HfAlO{sub x}(oxygen poor) bilayer structures exhibit multilevel resistive switching (RS), and the switching ratio becomes more prominent with increasing the HfAlO layer thickness. The bilayer structure with HfAlO/HfAlO{sub x} thickness of 30/40 nm displays the enhanced multilevel resistive switching characteristics, where the high resistance state/intermediate resistance state (IRS) and IRS/low resistance state resistance ratios are ≈10{sup 2} and ≈5 × 10{sup 5}, respectively. The switching mechanisms in the bilayer structures were investigated by the temperature dependence of the three resistance states. This study revealed that the multilevel RS is attributed to the coupling of ionic conduction and the metallic conduction, being the first associated to the formation and rupture of conductive filaments related to oxygen vacancies and the second with the formation of a metallic filament. Moreover, the bilayer structures exhibit good endurance and stability in time.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ; ;  [1]
  1. Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)
  2. (Brazil)
  3. (Portugal)
Publication Date:
OSTI Identifier:
22486236
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 24; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM OXIDES; COUPLING; DEPOSITION; FILAMENTS; HAFNIUM; ION BEAMS; LAYERS; OXYGEN; PHOTOLUMINESCENCE; RUPTURES; SPECTRA; SPUTTERING; SUBSTRATES; TEMPERATURE DEPENDENCE; THICKNESS; THIN FILMS; VACANCIES; VOLATILITY