Impedance and electric modulus study of amorphous TiTaO thin films: highlight of the interphase effect

The influence of phases and phase’s boundaries of TiO2 and Ta2O5 in the dielectric and electric response of TiTaO (100 nm thick) elaborated by RF magnetron sputtering was highlighted by complex impedance spectroscopy. Dielectric and electric modulus properties were studied over a wide frequency range (0.1–10 5 Hz) and at various temperatures (−160 to 120 ◦ C). The diagram of Argand (e �� versus e � ) shows the contribution of phases, phases’ boundaries and conductivity effect on the electric response of TiTaO thin films. Moreover, the resistance of the material decreases when the temperature increases, thus the material exhibits a negative temperature coefficient of resistance. The electric modulus plot indicates the presence of two peaks of relaxation. The first relaxation process appears at low temperature with activation energy of about 0.22 eV and it is related to the first ionization energy of oxygen vacancies. The second relaxation process appears at high temperature with activation energy of about 0.44 eV. This second peak is attributed to the Maxwell–Wagner–Sillars relaxation. The plots of the complex dielectric modulus and the impedance as a function of frequency allow concluding to a localized relaxation due to the long-range conductivity in the TiTaO film. (Some figures may appear in colour only in the online journal)

[1]  C. Wenger,et al.  Atomic Vapor Depositions of Ti–Ta–O thin films for Metal–Insulator–Metal applications , 2011 .

[2]  A. Chin,et al.  Leakage Current Improvement of Ni ∕ TiNiO ∕ TaN Metal-Insulator-Metal Capacitors using Optimized N + Plasma Treatment and Oxygen Annealing , 2007 .

[3]  M. Dionísio,et al.  Kinetics of free radical polymerization probed by dielectric relaxation spectroscopy under high conductivity conditions , 2011 .

[4]  Ashok Kumar,et al.  Impedance spectroscopy analysis of Ba0.7Sr03TiO3/La0.7Sr0.3MnO3 heterostructure , 2011 .

[5]  B. Tillack,et al.  Investigations of thermal annealing effects on electrical and structural properties of SrTaO based MIM capacitor , 2010 .

[6]  P. Mahapatra,et al.  Impedance spectroscopy study of Na1/2Sm1/2TiO3 ceramic , 2007 .

[7]  Rosario A. Gerhardt,et al.  Impedance and dielectric spectroscopy revisited: Distinguishing localized relaxation from long-range conductivity , 1994 .

[8]  E. Atanassova,et al.  Electrical characteristics of Ti-doped Ta2O5 stacked capacitors , 2008 .

[9]  R. Choudhary,et al.  Dielectric relaxation in Sr modified PST ceramics , 2007 .

[10]  F. Yeh,et al.  Higher-κ titanium dioxide incorporating LaAlO3 as dielectrics for MIM capacitors , 2010 .

[11]  C. Ang,et al.  Oxygen-vacancy-related low-frequency dielectric relaxation and electrical conduction in B i : S r T i O 3 , 2000 .

[12]  Li Zhang,et al.  Oxygen-vacancy-related dielectric anomaly in Ca Cu 3 Ti 4 O 12 : Post-sintering annealing studies , 2006 .

[13]  K. Jin,et al.  Effects of interfacial polarization on the dielectric properties of BiFeO3 thin film capacitors , 2008 .

[14]  Cheng-Fu Yang.  Improvement of the sintering and dielectric characteristics of surface barrier layer capacitors by CuO addition , 1996 .

[15]  M. Lagache,et al.  Study of the interfacial MWS relaxation by dielectric spectroscopy in unidirectional PZT fibres/epoxy resin composites , 2007 .

[16]  A. Sylvestre,et al.  Dielectric relaxation study of amorphous TiTaO thin films in a large operating temperature range , 2012 .

[17]  High-Performance Metal-Insulator-Metal Capacitor Using Quality Properties of High- κ TiPrO Dielectric , 2009 .

[18]  Metal-insulator-metal capacitors with MOCVD grown Ce-Al-O as a dielectric , 2011 .

[19]  K.C. Chiang,et al.  Very high-density (23 fF//spl mu/m/sup 2/) RF MIM capacitors using high-/spl kappa/ TaTiO as the dielectric , 2005, IEEE Electron Device Letters.

[20]  Friedrich Kremer,et al.  Broadband dielectric spectroscopy , 2003 .

[21]  A. Sylvestre,et al.  Impedance spectroscopic and dielectric analysis of Ba0.7Sr0.3TiO3 thin films , 2012 .