During ion bombardment, polymethylmethacrylate (PMMA) shows degassing of polymer components with a fluence and energy dependent contraction of the material, which leads to a material modification.
The ion beam induced chemical modification of the implanted layers was examined by means of X-ray photoelectron spectroscopy (XPS). The dependence of the chemical modification on beam current, ion fluence and ion energy was investigated for nitrogen implantations at energies ranging from 50 keV to 400 keV for ion fluences between 7×1013 / cm2 and 7×1015/cm2. Compared with the C-spectrum of virgin PMMA, the spectra of the implanted layers exhibited an increase of intensity of the 284.5 eV peak and the 286.4 eV peak. The ion beam induced modification led basically to generation of new C-o-groups. These generations show drastical changes in the dependence of the beam current and the ion fluence. Nevertheless, at a constant dose of 2×1014/cm2 the concentrations of the new groups did not indicate any energy dependence.