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

Journal Article · Tue Apr 21 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4917531· OSTI ID:22402869

Marichy, C. ^[1]; Sylvestre, A. ^[2]; Pinna, N. ^[3]

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1. Complexo de Laboratórios Tecnológicos, Universidade de Aveiro/CICECO, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal)
2. University Grenoble Alpes, G2Elab, F-38000 Grenoble (France)
3. Humboldt-Universität zu Berlin Institut für Chemie (Germany)

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.

• OSTI ID: 22402869
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 15; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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