Aqueous ionic effect on electrochemical breakdown of Si-dielectric\u2013electrolyte interface

Jeongse Yun,Kyungbae Oh,Taek Dong Chung,Kisuk Kang,Jae Gyeong Lee

doi:10.1038/s41598-020-73880-w

Abstract

The breakdown of thin dielectric films (SiO2, Si3N4, HfO2) immersed in aqueous electrolyte was investigated. The current and the kinetics of dielectric breakdown caused by large cathodic electric field applied across the dielectric layer reveal the electrochemical nature of dielectric materials. Electrolytes play a huge role in the established dielectric-electrolyte interface with respect to the overall electrical behavior of the system. Although aqueous cations are considered as spectator ions in most electrochemical systems, in dielectric interfaces the current–potential characteristics depend on the type of cation. Computer simulation based on density functional theory and molecular dynamics showed cations affect the dielectric strength. The responses of various dielectric films to solution components provide invaluable information for dielectric-incorporated electrochemical systems.

Highlights

The breakdown of thin dielectric films (SiO2, Si3N4, HfO2) immersed in aqueous electrolyte was investigated
In order to further elucidate the cation selectivity of SiO2-aqueous system, we investigated transportability of metal ions in S iO2 structure by ab-initio molecular dynamics (AIMD) simulations and theoretical calculations based on density functional theory (DFT) by assessing the relative stability of metal cations
We examined the effect of alkali metal and silver ions on the dielectric layer of Si-insulator-electrolyte (EOS) system under the condition of negative electrical bias

Summary

Introduction

The breakdown of thin dielectric films (SiO2, Si3N4, HfO2) immersed in aqueous electrolyte was investigated. The current and the kinetics of dielectric breakdown caused by large cathodic electric field applied across the dielectric layer reveal the electrochemical nature of dielectric materials. Aqueous cations are considered as spectator ions in most electrochemical systems, in dielectric interfaces the current–potential characteristics depend on the type of cation. Concerning the role of insulator as a material where the mass transport and electrochemical reactions of various species could take place, research hitherto has been focusing on mass transport and the redox process of cation species in the dielectric layer. Current leaks through the dielectric layer when applied electric field and cleaves chemical bonds which lead to local disruption and loss of insulating p roperty[19]. Ref is Ag/AgCl (3 M KCl) reference electrode with a double junction filled with 1 M K NO3. (b) Image of the electrochemical cell. (c) Typical current–potential curve of Si-insulator (10 nm)-aqueous electrolyte system

Methods

Results

Conclusion