[Raman spectra analysis of bromine doped hydrogenated amorphous carbon (a-C : Br : H) films deposited by RF-PECVD].

Bromine doped hydrogenated amorphous carbon (a-C : Br : H) thin films were deposited on silicon wafers by rf. -plasma enhanced chemical vapor deposition (RF-PECVD) with a frequency of 13.56 MHz at room temperature using pure bromoethane as a precursor of carbon source mixed with hydrogen (H2) as a carrier gas. The structures of the films prepared by partial pressure of mixed gas (C2 H5 Br/H2) were studied by Raman spectroscopy. The results indicate that the intensity of the Raman D peak is stronger, the Raman G peak positions shift up a little, and the value of I(D)/I(G) increases from 1.18 to 1.36, if the gas pressure of mixed C2 H5 Br/H2 is reduced gradually from 20 to 5 Pa. Meanwhile, the growth of thin film turns gradually into low energy mode promoting the transform of sp2-C from chains to rings.