Conventionally, microelectromechanical systems (MEMS) have been based mostly on silicon. 1 In this paper, we describe work carried out to evaluate carbon films produced by the pyrolysis of photoresists for use in MEMS and as electrode materials. 2 These carbon electrodes have potential applications in batteries, electrochemical sensors, and capacitors and in electrochemically based MEMS devices. The advantage of using photoresists as the starting material is that the photoresists can be patterned by photolithography techniques, and hence complex-shaped electrodes can be produced. Photoresists are used extensively in the integrated circuits industry and are very reproducible in their behavior, and hence the carbon films produced by pyrolyzing these photoresists constitute a potentially reliable carbon source.Carbon materials have been used extensively for electroanalytical chemistry, electrosynthetic chemistry, and energy conversion; several reviews are available. [3][4][5][6][7] Directly relevant to the current report are examinations of carbon films made from pyrolysis of gases, 8-13 pyrolysis of sublimed organic films, 14,15 sputtered carbon films, 16 pyrolyzed photoresists, 2,17,18 and patterned organic films of polyacrylonitrile 19,20 and poly(furfuryl alcohol) resin. [21][22][23] The electrochemical properties of these carbon materials vary with fabrication temperature and pretreatment procedures, but most show quasi-reversible electron-transfer behavior, with rate constants for Fe(CN) 6 3Ϫ/4Ϫ in the range of 10 Ϫ3 to 10 Ϫ2 cm/s. This report deals with the preparation, characterization, and electrochemical behavior of carbon films made from a positive photoresist material. The carbon films exhibit fast electron transfer to Fe(CN) 6 3Ϫ/4Ϫ and Ru(NH 3 ) 6 3ϩ/2ϩ , but also have unusual properties with respect to surface oxidation. Of emphasis in this study is the nature of the carbon surface and its suitability for electrochemical applications. ExperimentalCarbon film preparation.-A positive photoresist, AZ4330 (Hoechst Celanese, Somerville, NJ), was used to form conductive carbon films. The carbon films obtained from the AZ4330 photoresist are referred to as the AZ film. Silicon wafers (2 in. CZ, n-type, <1-0-0> oriented, 13-17 mil, 1-20 ⍀) were dipped in a dilute hydrofluoric acid solution before being spin-coated with a thin layer of the photoresist. The photoresist was applied manually on a silicon wafer 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 1100ЊC. 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 performe...