Properties of carbon films produced from polyimide by high-energy ion irradiation

The changes of composition and structure of polyimide films due to irradiation-induced carbonization were studied by surface characterization techniques and electric resistance measurement. Polyimide (C22H10N2O5)(n) film specimens were irradiated with 4 MeV Ni3+ ions for the fluences from 3.5 x 10(12) cm(-2) to 1.0 x 10(16) cm(-2). After irradiation with the fluence of 1.0x 10(16) cm(-2), the ratios of N/C and O/C decreased from 0.089 and 0.244 to 0.018 and 0.086, respectively. Though the absolute quantities of bond types were not clear, the portion of carbon-carbon bonds was obviously increased from 0.62 to more than 0.82. The generation of dispersed carbonized areas in the irradiated polyimide film was also suggested by Raman spectroscopy, electric resistance measurement and elastic recoil detection (ERD) analysis. (C) 2000 Elsevier Science B.V. All rights reserved.