X-RAY PHOTOELECTRON-SPECTROSCOPY STUDY OF SN-SI1-XCX-H THIN-FILMS( IMPLANTED A)

X-ray photoelectron spectroscopy was used to characterize a-Si1-xCx:H thin films deposited by r.f. magnetron sputtering and implanted with S n ions. Tin ion implantation results in modification of the optical ba nd gap and absorption coefficient of a-Si1-xCx:H films. The non-implan ted films show the expected variety of chemical bonds: silicon-silicon and silicon-carbon bonds, carbon being three- and fourfold coordinate d. The X-ray photoelectron and Raman spectra show that tin ion implant ation leads to the introduction of additional disorder in the films. T he X-ray photoelectron spectra of implanted films show that, in additi on to already mentioned bonds, tin creates new bonds with the host ele ments, the nature of which depends on the depth. This chemical modific ation and additional disordering are the reasons for the observed chan ges in the optical properties of the films. A model based on the energ y distribution of the implanted ions is proposed to explain the depth dependence of the nature of the chemical bonds which tin ions create d uring the implantation.