Direct current conduction properties of sputtered Pt/(Ba0.7Sr0.3)TiO3/Pt thin films capacitors

Abstract

Current flow through Pt/(Ba0.7Sr0.3)TiO3/Pt stack consists of both polarization current and electronic leakage current, which were separated by monitoring the discharging current when applied voltage was turned off. Electronic current comes from electrical field enhanced Schottky emission at the electrode–dielectric interface, and dominates the current flow at high electric field. At low electric field, polarization current prevails. The voltage and time dependence of the polarization current can be modeled by a distribution of Debye-type relaxations. The relaxation time and capacitance derived from current–time measurements were applied to simulate the current–voltage behavior, where good fitting to experimental result was obtained.

Temperature and voltage stress dependent dielectric relaxation process of the doped Ba0.67Sr0.33TiO3 ceramics

“…[2][3][4] This is referred to as the dielectric bolometer mode, in which the current evolution in the time domain after a constant voltage is applied on would exert a great influence upon the sensitivity of the device. A current decay regime has been observed by Hus et al 5 and H€ olbling et al 6,7 in BST thin films and p-type ST ceramics, respectively. The decay is usually thought to be caused by the relaxation process, which is analytically modeled by Debye-type relaxation 8 or Curie-von Schweidler law.…”

“…The relaxation time s i does not show significant dependence on the applied voltage, while the capacitance C i indicates downward trend with the increase of the voltage, which is different from the voltage independent capacitances derived from the BST thin film because no voltage suppressing effect on the permittivity is mentioned. 5 This downward trend derived here is easy to be understood by taking into consideration the dielectric nonlinearity induced by the voltage stress just above the Curie temperature, as shown in the inset of Fig. 1.…”

“…It is usual to replace the polarization current, induced by the relaxation process when the voltage is applied, with the depolarization current after the voltage removal to eliminate the influence of the leakage current. 5,11,12 However, as this method is only available to linear dielectric systems and certain relaxation mechanisms, previous research mainly focuses on the temperature range much over Curie temperature where the dielectric nonlinearity can be ignored, 11 which is deviated from the modified BST ceramics studied here. In this paper, a simple approach of more universality, through curve fitting, is developed to differentiate the leakage current and polarization current in-site when the voltage is applied.…”

The temperature dependence of the transient current in ferroelectric Pb(ZrxTi1−x)O3 thin films for memory devices applications

“…This type of transient current in PZT films has been observed previously. [14][15][16] The increase of transient current at high stress voltages is most likely due to the trapping of holes. The accumulation of trapped holes causes an enhancement of a͒ Electronic mail: ymlee@ee.nthu.edu.tw the local electric field in the film, thus increasing the conduction current.…”

“…The transient curves are polarization type at 100, 120, and 140°C. The transient current at room temperature (V app ϭ3 V) and at high temperatures ͑100-140°C, V app ϭ10 V͒ can be well fitted using a Debye-type relaxation model as shown in: 16,17 J͑t ͒ϭ…”