Electrochemical Impedance Spectroscopy of Dense Silica and Porous Silicon Oxycarbide

Analysis of Nanoporosity in Moisture Permeation Barrier Layers by Electrochemical Impedance Spectroscopy

“…This parameter is correlated with the surface area exposed to the surrounding environment and, hence, to the through-porosity. In the literature, porosity values have been measured for inorganic layers, such as SiO 2 , Al 2 O 3 , Ta 2 O 5 , and TiN. − Härkönen et al reported values down to 0.02% for ultrathin ALD deposited Al 2 O 3 layers, confirmed by the porosity calculated by means of linear scan voltammetry measurements. Tato et al detected porosity values down to 0.08% for thick sputtered TiN layers and compared them with the porosity values calculated with both dc and polarization methods.…”

Ellipsometric Porosimetry and Electrochemical Impedance Spectroscopy Characterization for Moisture Permeation Barrier Layers

“…In order to improve the fit and due to the presence of porosity, a constant phase element (CPE) is used to substitute all the system capacitances. A CPE can be defined as where i is the imaginary number, Q layer is a value independent of frequency, and α is the CPE power, which gives an indication of the layer inhomogeneity/porosity.…”

“…However, the EIS measurement highlighted differences in the macro‐scale defect level of the layers (Figure d). A second time constant developed in the Bode plot for the TVTSO‐deposited SiO 2 n 1.446 , which is generally attributed to the formation of an interface between the substrate and the electrolyte solution . To better highlight the differences in the macro‐scale defects content, the permeation of water was followed with EIS, as change of the C layer with the immersion time.…”

“…Next to EP, another technique is often used for microstructural analysis, namely electrochemical impedance spectroscopy (EIS) . The high sensitivity acknowledged to EIS makes it suitable for the characterization of a broad spectrum of thin films, in fields ranging from corrosion protection, to dye‐sensitized solar cells, fuel cells and batteries, and (bio‐) sensors . EIS has been already successfully applied in literature for the development and application of (ceramic) layers for the detection of water vapor, typically studied in a solid‐state configuration.…”

“…This parameter correlates with the surface area exposed to the environment and, hence, to the through‐porosity. In literature, porosity values have been measured for inorganic layers, such as SiO 2 , Al 2 O 3 , Ta 2 O 5 , and TiN …”