Fabrication of PPF Electrodes by a Rapid Thermal Process

This work describes the fabrication of pyrolyzed photoresist films (PPFs) using a rapid thermal process for the first time. A standard positive phenolic photoresist was deposited over a silicon wafer and heated in an inert atmosphere at rates in excess of 140 degrees C/min up to a temperature of 1000 degrees C. An annealing step of 1 h at that temperature was required to obtain a more complete graphitization of the resist and thus improve its electrochemical response. The PPF synthesized by this rapid thermal process showed one of the lowest resistivities reported to date for this kind of material (ca. 4-6 X 10(-3) Omega cm) but was slightly rougher than the PPF synthesized using slower thermal ramps (1.6 vs 0.5 nm). This rapid thermal process allows the fabrication, by direct lithoghraphy, of structures down to 50 mu m in width. The electrochemical behavior of our PPF closely resembled glassy carbon, as shown by the voltammetry of Fe(CN)(6)(4-/3-), Ru(NH3)(6)(3+/2+), Fe3+/2+, and dopamine. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3515169] All rights reserved.