Modification of magnetron-sputtered a-Si1-xCx : H films by implantation ofSn+ and Ge+

The review of the results on the optical contrast formation in a-Si1-xCx:H films by ion implantation of Sn+ and Ge+ is presented in this paper. The a- Si1-xCx:H films were deposited by RF magnetron co-sputtering of silicon and graphite in Ar + H-2 atmosphere. The expected optical effect which is an a bsorption edge shift to the lower photon energies accompanied by a consider able increase of the absorption coefficient was observed. This effect is mo re pronounced with an increase of the dose. Infrared (IR), photoelectron sp ectroscopy (XPS) and Mossbauer spectroscopy measurements were used to study the bond configurations of implanted films. Raman scattering and photodefl ection spectroscopy (PDS) show the increase of the short-range disorder and of the density of the states in the gap with the dose of the implanted ion s. The measurements reveal that ion implantation introduces an additional d isorder in the films as well as leads to their chemical modification, which is related to the changes of the optical properties. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.