Effect of OH⁻ Doping on the Dielectric Properties of Amorphous Ta₂O₅ Thin Films: A Combined First-Principles Calculations and Experimental Study

•OH⁻ doping creates localized metallic states in amorphous Ta₂O₅, initiating dielectric breakdown.•Higher electrolyte pH increases leakage current by ∼4.5 times and degrades dielectric properties.•Elevated pH promotes OH⁻ incorporation and crystallization, leading to extensive electrical treeing.•Co...

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Vydané v:Electrochimica acta Ročník 545; s. 147741
Hlavní autori: Zhao, Jiping, Li, Shiyu, Guo, Yeting, Zhao, Yuhan, Xu, Jingsong, Li, Yanling, Xu, Youlong
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: Elsevier Ltd 01.01.2026
Predmet:
Amorphous Ta₂O₅ films
Dielectric breakdown
First-principles calculations
OH⁻ doping
Tantalum capacitors
First-principles calculations
OH⁻ doping
Dielectric breakdown
Amorphous Ta₂O₅ films
Tantalum capacitors
ISSN:0013-4686
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Shrnutí:•OH⁻ doping creates localized metallic states in amorphous Ta₂O₅, initiating dielectric breakdown.•Higher electrolyte pH increases leakage current by ∼4.5 times and degrades dielectric properties.•Elevated pH promotes OH⁻ incorporation and crystallization, leading to extensive electrical treeing.•Controlling electrolyte pH is crucial for enhancing the reliability of solid-state tantalum capacitors. The pH value of the electrolyte during anodic oxidation exerts a complex influence on the dielectric properties of amorphous Ta₂O₅ films. However, the underlying atomic-scale mechanism remains poorly understood. Combining experimental characterization with first-principles calculations, this study elucidates that OH⁻ doping introduces additional density of states near the Fermi level, leading to localized metallic behavior within the Ta₂O₅ dielectric layer. With increasing electrolyte pH, severe electrical treeing and crystallization occur, resulting in an approximately 4.5-fold increase in leakage current and significant dielectric failure. Spectral and microstructural analyses confirm enhanced incorporation of OH⁻ and intensified crystallization under high-pH conditions. Computational results further demonstrate that doped OH⁻ species act as electron emission centers under high electric fields, initiating dielectric breakdown. These findings provide profound insights into the field-induced degradation mechanism in amorphous dielectric materials and underscore the critical importance of controlling electrolyte pH to enhance the reliability of solid-state tantalum capacitors. [Display omitted]
ISSN:0013-4686
DOI:10.1016/j.electacta.2025.147741