Polymers in Integrated Circuits

The last three decades have seen an explosive growth in silicon-based microelectronics. In search of flexible and low-cost substrates, organic semiconductorbased integrated circuits (ICs) have been suggested as an alternate to silicon ICs. The discovery that the electrical conductivity of some polymers can be increased from insulator to semiconductor range or metallic range by doping, has been driving force for research in this area [1]. The main processing techniques employed in the deposition of polymer films on glass or silicon substrates are electropolymeriztion, solution-processed deposition by casting, and vacuum evaporation [1]. Organic semiconductors (OSECs), which are usually divided into the classes of small molecular weight compounds and macromolecular polymers, have been used to manufacture promising devices such as organic lightemitting diodes (OLEDs) [2] and field-effect transistors [3][4]. Research into the electronic and optical properties of conjugated polymers began in the 1970s after a number of seminal experimental achievements. First, the synthesis of polyacetylene thin films and the subsequent success in doping these polymers to create conducting polymers established the field of synthetic metals. Second, the synthesis of phenyl-based polymers (e.g., polyfluorene (PFO)) and discovery of electroluminescence (EL) in these systems established the field of polymer optoelectronics. Polymers exhibit electronic properties that are quite different from those observed in inorganic metals or semiconductors [5].