Effect of Heating Rates during Sintering on the Electrical Properties of Ultra‐Thin Ni–BaTiO₃ Multilayer Ceramic Capacitors

Abstract

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 basemetal 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 30001C/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.

Electrical and reliability characteristics of Mn-doped nano BaTiO3-based ceramics for ultrathin multilayer ceramic capacitor application

“…1 Thus, the grain size of BT should decrease to about 200 nm or less, while at the same time the so-called "core-shell" structure should be preserved to fulfill the temperature-stable characteristics of the capacitance and a reliable performance in MLCCs. [22][23][24][25] At the same time, the reduction of the dielectric layer thickness directly implies the increase in the electric field applied to the dielectric layers. 9,26,27 Consequently, the reliability research is urgently important in ultra-thin MLCCs.…”

Low Temperature Epitaxial Growth of High Permittivity Rutile TiO[sub 2] on SnO[sub 2]

“…7 Recently, there has been extensive research on growing BST thin films on base-metal substrates to lower material cost. [10][11][12] Postdeposition annealing ͑400-750°C͒ in oxidizing ambient is necessary for making BST with a high dielectric constant, 12 but interfacial layers are introduced due to easy oxidation of base-metal electrodes, finally leading to a high EOT, which makes BST/base-metal stacks ineffective as well as complex to make.…”

A new sintering approach to ceramics at low temperature from Ba(ZrxTi1-x)O3 nanoparticles doped by ZnO

“…3, they disappear after suitable annealing at a temperature over 700 ℃. The small amount of BaCO 3 and its different contents in the as-prepared samples possibly derive from the raw material barium hydroxide, which can react with CO 2 in air during its storage. BaCO 3 can be synthesized into the perovskite structure while releasing CO 2 at a temperature as low as 500-700 ℃, because the decrease of BaCO 3 phase is clearly observed [26].…”

“…It is always important for the decrease of ceramic sintering temperature due to energy saving, co-firing of the ceramics with multiple ingredients, the necessity of certain inner electrodes for multiple layer functional ceramics, and so on. Both adding sintering aids in the ingredients and decreasing initial grain size of the ceramic powders are effective to lower sintering temperature [1][2][3]. In general, the sintering temperature theoretically decreases with the grain size of the ceramic powders.…”