Proceedings Article | 3 May 2007
KEYWORDS: Polymers, Polymethylmethacrylate, Heterojunctions, Diodes, Capacitors, Metals, Silicon, Aluminum, Lithography, Semiconductors
In this work, conducting polymer-based heterojunctions, diodes and capacitors have been generated using an
intermediate-layer lithography (ILL) approach which has been recently developed in our group. Polypyrrole (PPy) and
poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), Poly(methyl methacrylate) (PMMA) and
aluminum were used as component materials in these devices. Compared with Si-based devices, conducting polymerbased
devices have distinctive advantages of low weight and good flexibility, and may potentially replace the
corresponding Si-based devices. A challenge is how to fabricate the conducting polymer-based microsystems. Most
conducting polymers are sensitive to the environment, and their electrical properties tend to deteriorate over time due to
overoxidation (air), moisture, high temperature and chemical alteration. The current fabrication techniques (e.g. lift-off,
dry and wet etching processes) used in lithographic approaches involve ultra-violet, electron-beam, x-ray, gases (e.g.,
oxygen and nitrogen), DI water, and/or chemical solution (e.g. photoresist and acetone), making them improper to
pattern conducting polymers. Since the ILL method does not involve aggressive chemistry in generation of patterns, it
has been employed in this work to fabricate conducting polymer-based microdevices, particularly diodes and capacitors.
In fabrication of the devices, multiple layers of polymers (e.g., PPy and PEDOT) and metals (e.g., Al) are coated on a
PMMA sheet followed by the patterning with the insertion of Si molds. The detailed fabrication procedure and testing
results are given in this paper.
