Photoresist-derived carbon for microelectromechanical systems and electrochemical applications

Photopatterned resists pyrolyzed at different temperatures and different ambient atmospheres can be used as a carbonaceous material for microelectromechanical systems. Carbon films were prepared by pyrolysis of photoresists at temperatures ranging from 600 to 1100 degrees C. The carbon films were characterized by several analytical techniques, viz., profilometry, thermogravimetric analysis, four-point probe measurements, scanning electron microscopy, transmission electron microscopy, atomic force microscopy. X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. In addition, cyclic voltammetry was performed on the carbon film electrodes, and the carbon films were compared to glassy carbon (GC) for their electrochemical behavior. Electron-transfer rate constants for the benchmark Fe(CN)(6)(3-/4-) and Ru(NH3)(6)(3+/2+) redox systems increased with increasing heat-treatment temperature, and approached those observed on GC following treatment at 1100 degrees C. The pyrolyzed films have low capacitance and background current, approximately one-fourth of that observed on GC. The oxygen/carbon atomic ratio determined from XPS was low (similar to 1% for 1100 degrees C pretreatment), and increased more slowly upon exposure to air than that for GC treated under identical conditions. Pyrolysis of photoresist Alms permits photolithographic fabrication of carbon electrode devices, and also appears to yield a carbon film with a smooth surface and unusual surface chemistry. (C) 2000 The Electrochemical Society. S0013-4651(99)02-055-8. All rights reserved.