Electrical properties of (Ba,Sr)TiO3 thin films revisited: The case of chemical vapor deposited films on Pt electrodes

Abstract

Due to the dependence on both bulk and interface properties neither the effective dielectric constant nor the leakage current J can be scaled in a straightforward manner with film thickness for highthin film capacitors. Based on detailed investigations of different thickness series of ͑Ba, Sr͒TiO 3 films on platinized substrates the bulk and interfacial properties are separated. An approach to estimate the apparent interfacial layer thickness is discussed. The behavior of the leakage current is divided in two regions: for low voltages, ഛ1 V, the currents are very low, ഛ10−10 A/cm 2 , and dominated by the relaxation currents ͑Curie-von Schweidler behavior͒. At higher voltages the change to a very strong power law dependence is observed, J ϳ E 16 . The thickness dependence is removed by scaling with the internal field or dielectric displacement of the film, D = 0 E. Hence, a direct connection between the increase in and the increase in leakage with film thickness is revealed. This behavior is accompanied by a larger scatter of the data and seems to be controlled by a more inhomogeneous or local conductivity. Influences of the measuring temperature and of stoichiometry and interfacial properties are discussed.

Oxygen vacancy diffusion in bulk SrTiO3 from density functional theory calculations

“…A V O is generally produced during crystal growth or film deposition processes with nonstoichiometric reactants, as a result of oxygen gas release accompanying heat treatment, and in doped STO serving as a charge compensation mechanism. They form readily within STO and have been indicated to be the driving force behind STOassociated blue and green light emission 10,11 and high n-type conductivity 12,13,14,15 . Therefore, fully understanding the stability and diffusion of V O is critical for tailoring the physical properties of STO for future applications.…”

Oxygen vacancy migration in compressively strained SrTiO3

“…8 A large body of work, both the experimental and theoretical, has been directed toward an explanation for the origin of leakage current and the mechanisms underlying resistive switching. 7,[9][10][11][12] The majority of models feature oxygen vacancies, V O , in a central role. 7,[12][13][14][15] Importantly, although the involvement of V O in the electrical and other properties of SrTiO 3 films inferred from experiment may be largely circumstantial, the electronic, electrical, thermodynamic, and kinetic properties of V O have been established using quantum-chemical simulations.…”

A comprehensive study on the leakage current mechanisms of Pt/SrTiO3/Pt capacitor

“…Leakage current through transition metal oxides has been the subject of extensive discussion, and different models have been proposed to explain it. [6][7][8][9][10] Thermionic field emission equations (i.e., Schottky or Poole-Frenkel) are frequently used to explain temperature dependent characteristics of leakage current, which is mainly attributed to oxygen vacancies. 4,7,8,11,12 The conduction mechanism of the oxygen vacancies was also found to vary according to the difference in the thermionic field emission types (either Schottky or Poole-Frenkel).…”