Effect of Bias on Content of GeC in Ge _1-x C_x Films

Ge _1-x C_x films with GeC content up to 11.6% can be prepared by using a medium frequency magnetron sputtering technique in our study. X-ray photoelectron analysis for these Ge _1-x C_x films shows that the Ge _1-x C_x films consist of C, Ge, GeC and GeO_y. The content of GeC increases from 10.7% at 0V to 11.6% at 250V, and decreases to 9.6% at 350V, and then increases again to 10.4% at 450V. The Raman analysis confirms the result of XPS for checking GeC in the deposited Ge _1-x C_x films. The related mechanism is discussed.