Material contrast studies of conductive thin films on semiconductor substrates using scanning electrochemical microscopy
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In this paper, a mediator-free scanning electrochemical microscopy (SECM) imaging concept is presented, which is capable of generating high electrochemical contrast and high spatial resolution between two conductive materials. The methodical approach is based on the hydrogen evolution reaction which shows potential dependent material selectivity. Various conductive thin films deposited on silicon substrates were studied. The investigated materials included copper, ruthenium, platinum, tantalum nitride, and titanium nitride. The hydrogen evolution was studied with chronoamperometry (Esubstrate = 1 V vs. Ag/AgCl/3 M KCl) to characterize the material selectivity of this reaction for the above-listed thin films. SECM imaging in the substrate generation-tip collection (SG/TC) mode was carried out and applied to study the boundary regions of thin copper films in combination with the aforementioned thin film materials. In addition, the spatial resolution of hydrogen based SG/TC SECM imaging was characterized using lithographically fabricated platinum/copper structures as test substrates. For comparison, the common feedback mode was also applied for SECM imaging of the conducting thin film combinations. It was found, that only the hydrogen based SG/TC mode enabled SECM imaging with clear material contrast between different conductive materials which was not possible in the feedback mode.
KeywordsScanning electrochemical microscopy Hydrogen evolution reaction Thin film metals Substrate generation-tip collection mode
Timo Raith gratefully acknowledges the financial support from the Studienstiftung des deutschen Volkes.
- 19.Vielstich W, Gasteiger HA, Yokokawa H (2009) Handbook of fuel cells: fundamentals technology and applications: advances in electrocatalysis, materials, diagnostics and durability. John Wiley & Sons, HobokenGoogle Scholar
- 26.Fernández JL, Zoski CG (2018) Voltammetric and scanning electrochemical microscopy investigations of the hydrogen evolution reaction in acid at nanostructured ensembles of ultramicroelectrode dimensions: theory and experiment. J Phys Chem C 122:71–82. https://doi.org/10.1021/acs.jpcc.7b08976 CrossRefGoogle Scholar
- 30.Hanekamp P, Robl W, Matysik FM (2017) Development and application of a multipurpose electrodeposition cell configuration for studying plating processes on wafer specimen and for characterizing surface films by scanning electrochemical microscopy. J Appl Electrochem 47:1305–1312. https://doi.org/10.1007/s10800-017-1124-8 CrossRefGoogle Scholar
- 37.Smith FG, King TA (2007) Optics and photonics: an introduction. John Wiley & Sons, HobokenGoogle Scholar