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Effect of Heating Rates during Sintering on the Electrical Properties of Ultra‐Thin Ni–BaTiO 3 Multilayer Ceramic Capacitors
Author(s) -
Polotai Anton V.,
Fujii Ichiro,
Shay Dennis P.,
Yang GaiYing,
Dickey Elizabeth C.,
Randall Clive A.
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2008.02517.x
Subject(s) - materials science , ceramic capacitor , sintering , dielectric , capacitor , composite material , electrode , ceramic , capacitance , alloy , grain size , metallurgy , optoelectronics , voltage , electrical engineering , chemistry , engineering
Microstructural control in thin‐layer multilayer ceramic capacitors (MLCCs) is one of the present day challenges for increasing capacitive volumetric efficiency and high voltage dielectric properties. The present paper continues a series of investigations aimed at engineering the stability of ultra‐thin Ni layers in base‐metal electrode MLCCs. A kinetic approach based on the control of sintering profiles is found to not only prevent Ni electrode discontinuities, but also to significantly improve the interfacial electrical properties. Increasing sintering heating rates from 200 to 3000°C/h leads to a decrease in its temperature dependence of capacitance. Faster heating rates also reduce the BaTiO 3 grain size, which is beneficial to the reliability of multilayer capacitors. A direct correlation between heating rates, the thickness of an interfacial (Ni, Ba, and Ti) alloy reaction layer and the interfacial contact resistance has been observed. The decrease in the alloy layer thickness at high heating rates leads to an increased effective Schottky barrier height between the dielectric and electrode toward its theoretical value of 1.25 eV for pure Ni–BaTiO 3 interfaces.