Impact of surface properties on the dielectric breakdown for polycrystalline and multilayered BaTiO3 thin films

Abstract

The dielectric reliability for polycrystalline and multilayered BaTiO 3 thin films has been evaluated using time-zero and time-dependent dielectric breakdown techniques. The histogram of dielectric breakdown for multilayered BaTiO 3 thin films showed a typical Weibull distribution in contrast to a random distribution when compared with polycrystalline BaTiO 3 thin films. The measurement resulted in that the 400 nm-thick multilayered BaTiO 3 thin film sustained about 10 5 hour-long operation at 1 MV/cm, showing superior properties when compared with polycrystalline. The smaller leakage current level was obtained for a multilayered BaTiO 3 film having a relatively thick underlayer of polycrystalline BaTiO 3 film. The value of the breakdown field was smaller at the thicker multilayered BaTiO 3 while the distribution of the breakdown widened for thicker film. Analysis of the roughness for the films confirmed that the field breakdown mechanism ͑e.g., lowering and spreading͒ is related to the surface roughness of the topmost layer which varies with the thickness of underlying polycrystalline BaTiO 3. The reduced leakage current at the thick multilayered BaTiO 3 was due to the presence of a wide transition layer between polycrystalline and amorphous BaTiO 3 .

Electrode Defects in Multilayer Capacitors Part I: Modeling the Effect of Electrode Roughness and Porosity on Electric Field Enhancement and Leakage Current

“…13,26,32,33 The Poole-Frenkel current is given as: The Poole-Frenkel mechanism is dominant when the leakage current is governed by a large number of charged traps in the bulk.…”

“…The presence of rough interfaces and electrode discontinuities has been found to be detrimental to the miniaturization of such devices in many ways. [12][13][14][15][16] The interface roughness has also been found to influence the conductivity of metallic and semiconducting films. Previous works have revealed roughness at metal-insulator interface as sites of electric field enhancement.…”

Effect of Firing Rates on Electrode Morphology and Electrical Properties of Multilayer Ceramic Capacitors

“…[4][5][6][7][8][9] Local field enhancements arising from electrode discontinuities and rough interfaces lead to a lower dielectric breakdown strength, a higher steady-state leakage current, and limited performance in terms of operating voltage, yield, and capacitance levels for specific geometries. [10][11][12][13] Prior studies by Gaillard et al and Lopes et al demonstrated the dependence of leakage current on the metal-insulator interface morphology due to local electric field enhancements around roughness. 7,14 In the past, some of these observations have been quantified by calculating the electric field distribution in the presence of electrode defects such as porosities and roughness.…”

“…Microstructural defects such as rough interfaces and electrode discontinuities have been found to affect the device properties adversely . Local field enhancements arising from electrode discontinuities and rough interfaces lead to a lower dielectric breakdown strength, a higher steady‐state leakage current, and limited performance in terms of operating voltage, yield, and capacitance levels for specific geometries . Prior studies by Gaillard et al .…”

Influence of self-affine and mound roughness on the surface impedance and skin depth of conductive materials

“…For example, random rough surfaces have been shown to influence drastically the image potential of a charge situated in the vicinity of the interface plane between vacuum and a dielectric [3], as well as inversion layers at semiconductor/oxide interfaces, because roughness induces a shift of the electronic levels [4]. Also surface/interface roughness has been shown to influence strongly the electrical conductivity of semiconducting and metallic thin film [5], as well as the electric field breakdown mechanism at a metal/insulator interface [6].…”