Analysis of the Ge1 xCx films deposited by MFMST

Ge1 xCx films deposited by using a medium frequency magnetron sputtering technique (MFMST) were analyzed with X-ray photoelectron and Raman spectroscopy. The deposited Ge1 xCx films consist of C, Ge, GeC and GeOy. The GeC content in the Ge1 xCx films linearly decreases, and the C content linearly increases with increasing deposition temperature from 150 to 350 8C. The GeC content decreases from 11.6% at a substrate bias of 250 V to a lowest value of 9.6% at 350 V, then increases again to 10.4% at 450 V. While the C content increases from 49.0% at the bias of 250 V to a largest value of 58.0% at 350 Vand then maintains this level at 450 V. It is found that selecting a bias parameter seems more effective than deposition temperature if we want to obtain a higher content of GeC in the deposited films. In addition, a new method is presented in this paper to estimate the changes of GeC content in the Ge1 xCx films by observing the shifts of Ge–Ge LO phonon peak in Raman spectra for the Ge1 xCx films. The related mechanism is also discussed in this paper.