Photodefinable carbon films: Electrical properties

Carbon images were prepared by the thermal decomposition of photodefined novalac resist (HPR-206) patterns. The electrical resistivity of the films decreased over 18 orders of magnitude as the pyrolysis temperature was increased to 1050°C. The electrical characteristics of the pyrolyzed photoresist patterns (carbon images) undergo a series of transitions over this temperature range; from insulating, to semiconducting, to semimetallic states. These properties may be understood in terms of the tunneling of charge carriers between isolated, conductive regions in the film where trigonal bonding dominates. This is the first example of the direct lithography of semiconducting and semimetallic features.