Fluence dependence of the interband critical points in ion-implanted silicon

bFluence (Phi) dependence of interband critical points (CPs) can help to mo nitor the variation of band structure in crystalline-amorphous (c-a) silico n interfaces under ion implantation. Silicon wafers (1 0 0) were implanted in the range of 200-900 keV with Si, Ar, Kr and Xe ions with different flue nces. The techniques used and the damage profiles have been demonstrated el sewhere [1]. Real and imaginary parts of the dielectric constant were calcu lated from the recently measured ellipsometric parameters (phase difference triangle and amplitude ratio Psi) [1,2]. The observed structures are analy zed by fitting the second-derivative spectra for complete line shape for bo th real and imaginary parts of the dielectric function d(2)epsilon/dw(2) wi th analytic critical point line shapes. The interband critical point parame ters (strength, threshold energy, broadening and excitonic phase angle) hav e been considered. The variations of these parameters were used to monitor crystalline-amorphous transformation. Obtained results of unimplanted cryst als were in fair agreement with previously published data [3-13]. (C) 2000 Elsevier Science B.V. All rights reserved.