Scanning Electrochemical Microscopy versus Scanning Ion Conductance Microscopy for Surface Patterning

Scanning electrochemical microscopy (SECM) offers an alternative approach for precise local electrodeposition of micro- and nanometer structures driven by electrochemistry. The tip generation and substrate collection mode of SECM has been applied to deposit sub-micron palladium structures by using a Pd microelectrode. This was compared with a different approach based on scanning ion conductance microscopy (SICM). The latter was utilized also for the localized electrochemical deposition of Pd patterns using a pulled micropipette as a tip. The micropipette was filled with PdCl₄ ²⁻ and biased versus a reference electrode placed in a NaCl solution. The application of a negative potential to the micropipette causes negatively charged ions, PdCl₄ ²⁻, to egress the pipette, which were electrochemically reduced on a conducting surface. The Pd patterns locally deposited by SECM and SICM were used for the local electroless deposition of Cu. Comparison between the two techniques shows that SICM is superior to SECM in terms of resolution and ease of tip preparation.