Dielectric Breakdown and Post-Breakdown Dissolution of Si/SiO2 Cathodes in Acidic Aqueous Electrochemical Environment

Jeongse Yun, Yun Bin Cho, Woohyuk Jang, Jae Gyeong Lee, Samuel Jaeho Shin, Seok Hee Han, Youngmi Lee, Taek Dong Chung

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2 Scopus citations

Abstract

Understanding the conducting mechanisms of dielectric materials under various conditions is of increasing importance. Here, we report the dielectric breakdown (DB) and post-breakdown mechanism of Si/SiO2, a widely used semiconductor and dielectric, in an acidic aqueous electrochemical environment. Cathodic breakdown was found to generate conduction spots on the Si/SiO2 surface. Using scanning electrochemical microscopy (SECM), the size and number of conduction spots are confirmed to increase from nanometer to micrometer scale during the application of negative voltage. The morphologies of these conduction spots reveal locally recessed inverted-pyramidal structures with exposed Si{111} sidewalls. The pits generation preceded by DB is considered to occur via cathodic dissolution of Si and exfoliation of SiO2 that are induced by local pH increases due to the hydrogen evolution reaction (HER) at the conduction spots. The HER at the conduction spots is more sluggish due to strongly hydrogen-terminated Si{111} surfaces.

Original languageEnglish
Article number1911
JournalScientific Reports
Volume8
Issue number1
DOIs
StatePublished - 1 Dec 2018

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