skip to main content

Title: Anomalous C-V response correlated to relaxation processes in TiO{sub 2} thin film based-metal-insulator-metal capacitor: Effect of titanium and oxygen defects

Capacitance-voltage (C–V) and capacitance-frequency (C–f) measurements are performed on atomic layer deposited TiO{sub 2} thin films with top and bottom Au and Pt electrodes, respectively, over a large temperature and frequency range. A sharp capacitance peak/discontinuity (C–V anomalous) is observed in the C–V characteristics at various temperatures and voltages. It is demonstrated that this phenomenon is directly associated with oxygen vacancies. The C–V peak irreversibility and dissymmetry at the reversal dc voltage are attributed to difference between the Schottky contacts at the metal/TiO{sub 2} interfaces. Dielectric analyses reveal two relaxation processes with degeneration of the activation energy. The low trap level of 0.60–0.65 eV is associated with the first ionized oxygen vacancy at low temperature, while the deep trap level of 1.05 eV is associated to the second ionized oxygen vacancy at high temperature. The DC conductivity of the films exhibits a transition temperature at 200 °C, suggesting a transition from a conduction regime governed by ionized oxygen vacancies to one governed by interstitial Ti{sup 3+} ions. Both the C–V anomalous and relaxation processes in TiO{sub 2} arise from oxygen vacancies, while the conduction mechanism at high temperature is governed by interstitial titanium ions.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Laboratory for Materials, Organization and Properties (LabMOP), 2092 Tunis (Tunisia)
  2. (France)
  3. Complexo de Laboratórios Tecnológicos, Universidade de Aveiro/CICECO, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal)
  4. University Grenoble Alpes, G2Elab, F-38000 Grenoble (France)
  5. Humboldt-Universität zu Berlin Institut für Chemie (Germany)
Publication Date:
OSTI Identifier:
22402869
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 15; 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; ACTIVATION ENERGY; CAPACITANCE; CAPACITORS; DIELECTRIC MATERIALS; ELECTRIC POTENTIAL; EV RANGE; FREQUENCY DEPENDENCE; INTERFACES; LAYERS; OXYGEN; RELAXATION; TEMPERATURE DEPENDENCE; THIN FILMS; TITANIUM; TITANIUM IONS; TITANIUM OXIDES; TRANSITION TEMPERATURE; VACANCIES