Chemical reactions in polymers induced by ion beam mixing: fluorescence X-ray measurements

Fluorescent soft X-ray emission spectroscopy (XES) is used to study chemica l reactions in polyimide (PI), polyethersulphone (PES) and polycarbosilane (PCS) films induced by ion-beam mixing. It is found that the fine structure of the carbon XES of the PI and PES films is modified after irradiation wi th fluences above 1x10(14) cm(-2), which is attributed to the degradation o f the molecular structure in amorphous C:N:O, The width of the electronic g ap decreases with the ion fluence, in correlation with reported increase of conductivity and optical absorption. The bonding configuration of free car bon precipitated in a matrix of a-SiC after irradiation of PCS is closer to that of diamond-like carbon than in a film submitted to combined treatment s of irradiation+annealing or direct annealing. Nevertheless clusters forme d in the annealed PCS films are less sp(2)-hybridized than in silicidated g raphite or sputtered Si:C:H films. (C) 2000 Elsevier Science BN. All rights reserved.