Improved reliability predictions in high permittivity dielectric oxide capacitors under high dc electric fields with oxygen vacancy induced electromigration

Abstract

This paper attempts to improve upon the range of applicability and predictability of the empirical highly accelerated lifetime testing (HALT) equation that has been traditionally used to estimate time dependent breakdown strength performance in multilayer ceramic capacitors (MLCC) and integrated thin film capacitor structures. The present and traditional HALT equation shows evidence of being limited in thin dielectric layers under high fields, for example, in high capacitance MLCCs. When the traditional HALT equations are applied to MLCCs with higher operating electric fields, there are often field dependent voltage acceleration factors resulting in ambiguous data analysis. Here, we introduce a physical model to account for a critical ionic space charge accumulation preceded by the ionic hopping or electromigration of oxygen vacancies leading to an ultimate increase in leakage current typical of dielectric resistance degradation. Mean time to failure degradation data on experimental capacitors indicates superior predictions with the new non-linear equation than with the traditional HALT equation to provide more accurate and simpler testing in future components. It is further noted that this approach may be applicable to many capacitive devices that operate under a high bias and can have ionic space charge accumulation at interfaces prior to breakdown.

Role of polaron hopping in leakage current behavior of a SrTiO3 single crystal

“…14 The main objective of this work is to test the hypothesis that polaron hopping makes important contribution to the leakage current evolution. The temporal profiles of polaron evolution were obtained by solving the diffusion equation using boundary conditions (11) and (12). The initial polaron concentration in SrTiO 3 was estimated to be 10 14 cm À3 based on literature.…”

“…9 12 Strukov et al provided a model of coupled drift-diffusion equations for electrons and ions and examined the mobile ion distributions and current-voltage characteristics of thin film semiconductor memristor. 13 With all of this interest in coupled electronic and ionic conduction in mixed oxide functional materials, there is a need for deeper understanding of the transient processes that occur on a local and macroscopic scale in these materials.…”

Formation of structural defects and strain in electrodegraded Fe‐doped SrTiO3 crystals due to oxygen vacancy migration

“…The vacancy results in a displacement of the central Fe 3+ cation and bending of the a‐ axis oxygen bonds, as shown in Figure D. This defect is positively charged with respect to the crystal lattice …”

“…Perovskite‐based (ABO 3 ) insulating and semiconducting transition metal oxides, such as SrTiO 3 (STO), BaTiO 3 , and TiO 2 , continue to garner research interests for their applications in capacitors, thermistors, actuators, sensors, and resistance random access memory devices . Although these materials exhibit desirable properties for applications in microelectronics, their reliability, lifetime, and overall performance are limited by the onset of breakdown induced by high electrical and thermal stresses . Of particular importance for improving electroceramic reliability and lifetime is to fully understand and resolve the phenomenon known as voltage‐induced resistance degradation.…”

High‐Temperature Multilayer Ceramic Capacitors Based on 100−x(94Bi1/2Na1/2TiO3–6BaTiO3)–xK0.5Na0.5NbO3

“…[6][7][8] The formation of MLCCs comprised of market dominating BaTiO 3 has been studied for many years, resulting in a steady improvement of properties. 9,10 Although some efforts have been made to increase the Curie temperature, the upper limit achieved is still below 200°C, which is too low for the type of high-temperature applications of interest. 11 There are some commercial high-temperature-MLCCs made with paraelectric materials stable to 200°C (Kemet High-Temperature C0G series).…”