Localized Electrochemical Deposition of Copper Microstructures

Abstract

Nanostructures are becoming increasingly important for technology and basic science. 1 Fabrication techniques currently employed for material deposition include low-pressure chemical vapor deposition (LPCVD), 2 laser-assisted chemical vapor deposition (LCVD), 3 plasma-enhanced chemical vapor deposition (PECVD), 4,5 ultraviolet stereo lithography, 6 spinning, 7 dipping, 8 spraying, 9 and electrodeposition. [10][11][12][13][14][15] Electrodeposition methods have many advantages over the other stated techniques and are attractive, as they are simple, inexpensive, reproducible, and damage-free. In addition, many materials can be deposited using electrodeposition, including metals, metal alloys, conducting polymers, and semiconductors with essentially no limitations on the size of the substrate or on the thickness of the deposited material. 16 Scanning probe microscopy (SPM) such as scanning tunneling microscopy (STM), 17 atomic force microscopy (AFM), 18 and scanning electrochemical microscopy (SECM) 19 has been widely used as a tool for surface imaging with atomic resolution. Furthermore, creation of structures using SPM has lately attracted considerable attention. 20-23 Using SPM for surface modification has advantages in that the modification process can be followed in real time and submicrometer resolution can be achieved. 24-25 SPM-based nanofabrication has potential uses in applications such as high-density information storage, high-resolution lithography, and production of nanoscale integrated chemical systems and electronic devices.Several groups have employed SPM to deposit metal and polymer microstructures. [28][29][30][31] Bard et al. 32 used the SECM to deposit different metals (e.g., Cu, Ag, Au, Pd) on polymer-coated substrates, whereas Shahat and Mandler et al. used the same technique to deposit Ni(OH) 2 structures 33 from aqueous solutions by changing the pH locally on the substrate and gold patterns by the controlled dissolution of a gold ultramicroelectrode (UME) tip. 34 Wipf and Zhou 35 used the "microreagent" SECM mode to deposit conducting polyaniline patterns on different substrates. Lagraff and Gewirth 36 employed the tip of an AFM to direct the growth of nanoscopic copper protrusions, whereas Madden and Hunter used a tip-directed scheme to deposit several micrometer-scale nickel structures. 25 In tip-directed localized deposition, 32 a faradaic current flows through the solution between a UME tip and a metal substrate electrode all immersed in an ionically conducting electrolyte when a bias voltage is applied between these two electrodes. If reducible metal ions are present in the electrolyte (e.g., Cu 2ϩ ions) and the substrate electrode potential is negative with respect to the tip electrode, then the passage of the faradaic current results in the deposition of metal on the substrate and an oxidation process at the tip. The magnitude of the faradaic current is kept constant by means of a conventional feedback control that monitors the current and adjusts the interelectrode spacing according...

Scanning electrochemical microscopy: study of the deposition and stripping mechanism of lead in the presence of copper

“…A variety of in situ techniques are now available, including the electrochemical quartz crystal microbalance (EQCM), [1][2][3] electrochemical scanning tunnelling microscopy (STM) 4,5 and scanning electrochemical microscopy (SECM). [6][7][8][9][10] The SECM is a scanning probe microscopy (SPM), and as all SPMs, they operate by scanning or "rastering" a small probe tip over a surface to be investigated. In the SECM, the tip is an ultramicroelectrode (UME), which can be operated under amperometric or potentiometric conditions.…”

Investigation of Localized Catalytic and Electrocatalytic Processes and Corrosion Reactions with Scanning Electrochemical Microscopy (SECM)

“…The UME current is balanced by i S that is of the same size and opposite direction. If i S can be confined to a small area close to the UME, local surface modification or analysis can be performed [120][121][122][123] (Figure 9). The confinement of the reaction is achieved by one of the following concepts: -The experiment is performed with a probe penetrating or touching a thin polymeric electrolyte [120,124].…”

Silver and Copper Microstructures: The Workfunction’s Effect

“…Currently, the synthesis of nanowires by the electrochemical deposition is of great interest. To fabricate and investigate the growth mechanisms of metal nanowires in the cylindrical pores of a template is of essential and technological interests [7][8][9][10][11][12]. The template-assisted synthesis of nanowires is a conceptually simple and intuitive way to fabricate nanostructures [13,14].…”