Microfabrication of Glassy Carbon by Electrochemical Etching

Abstract

Due to the broad impact of microfabrication technology on chemistry and biology, new methods to pattern and etch a variety of materials are being explored in a number of laboratories. We have developed a method for the etching of glassy carbon ͑GC͒ that opens pathways for the creation of new electrode patterns and devices. The method involves standard pattern transfer to a photoresist layer and anodization of the exposed GC substrate in basic electrolyte. The electrode reaction results in a breakup of the carbon lattice and likely involves the intercalation of hydroxide anions. The depth of etching can be controlled with potential, time or charge. The etching process is isotropic due to the nano-scale graphitic microcrystallite size of GC. We demonstrate the fabrication of microchannel structures directly into GC and the preparation of arrays of submicrometer sized carbon electrodes via the etching of patterned carbon films.

Highly sensitive determination of chlorpromazine by electrochemically treated pencil graphite fiber as both solid-phase microextraction fiber and working electrode for use in voltammetry method

“…[23][24][25] Formation of carbonyl, phenolic groups, lactone, ether, quinine, hydroxyl and carboxyl as a graphite oxide lm has been previously reported. [23][24][25] Formation of carbonyl, phenolic groups, lactone, ether, quinine, hydroxyl and carboxyl as a graphite oxide lm has been previously reported.…”

“…[23][24][25] Formation of carbonyl, phenolic groups, lactone, ether, quinine, hydroxyl and carboxyl as a graphite oxide lm has been previously reported. This lm increases the electrode surface area 23 and contains many anionic sites, and it is permeable to solvent and small molecules. This lm increases the electrode surface area 23 and contains many anionic sites, and it is permeable to solvent and small molecules.…”

A Comprehensive Review of Micro/Nano Precision Glass Molding Molds and Their Fabrication Methods

“…Mekaru et al [ 114 ] reported an etch rate of 1.8 nm/s with oxygen and sulfur hexafluoride plasma, which was attributed to the fact that the dry etching of GC material is very slow. Moreover, solution-based chemical etching is rarely utilized for GC mold fabrication because GC exhibits isotropic etching behavior due to its amorphous structure [ 115 ].…”

Glassy Carbon: A Promising Material for Micro- and Nanomanufacturing

“…However, FIB milling [ 30 ] and various dry [ 31 ] and wet [ 28 ] etching methods have been effectively used to pattern it. Its exceptional inertness makes the chemical (wet) etching challenging, but an electrochemically assisted wet etch is generally possible [ 28 ], since glassy carbon does exhibit an electrochemical corrosion [ 121 ]. Dry etching is often carried out with the aid of reactive ions and/or high-density plasma.…”

“…In addition to the carbonization of patterned polymers, device-compatible micro/nano structures can be realized by directly machining glassy carbon. Although this material is difficult to machine, methods, such as electrochemical [ 28 ] and thermochemical [ 29 ] etching, Focused Ion Beam (FIB) milling [ 30 ], and laser machining [ 31 ] have been employed to pattern it. In this contribution, some recent glassy carbon micro/nano devices fabricated using both strategies are described.…”