SOFT-X-RAY FLUORESCENCE MEASUREMENTS OF IRRADIATED POLYMER-FILMS

Fluorescent soft X-ray carbon K alpha emission spectra (XES) have been used to characterize the bonding of carbon atoms in polyimide (PI) an d polycarbosilane (PCS) films. The PI films have been irradiated with 40 keV nitrogen or argon ions, at fluences ranging from 1x10(14) to 1x 10(16) cm(-2). The PCS films have been irradiated with 5x10(15) carbon ions cm(-2) of 500 keV and/or annealed at 1000 degrees C. We find tha t the fine structure of the carbon XES of the PI films changes with im planted ion fluence above 1x10(14) cm(-2) which we believe is due to t he degradation of the PI into amorphous C:N:O. The width of the forbid den band as determined from the high-energy cut-off of the C K alpha X -ray excitation decreases with the ion fluence. The bonding configurat ion of free carbon precipitates embedded in amorphous SiC which are fo rmed in PCS after irradiation with C ions or combined treatments (irra diation and subsequent annealing) is close to either to that in diamon d-like films or in silicidated graphite, respectively. (C) 1998 Elsevi er Science B.V. All rights reserved.