Silicon–carbon thin films deposited by excimer lamp-CVD from disilane and ethylene.

Abstract Amorphous hydrogenated silicon–carbon layers have been prepared from disilane and ethylene precursors by Xe ∗ 2 excimer lamp induced-chemical vapour deposition. The influence of the substrate temperature, in the range between 100°C and 300°C, on the film properties has been determined by different characterization techniques. Ellipsometric measurements give film growth rates between 0.9 and 2.1 nm/min, and refractive index values following an increasing tendency with temperature from 2.3 to 3.9. The band gap was calculated from the optical absorption measurements, exhibiting a linear decreasing tendency with the substrate temperature from 2.5 to 1.7. Films produced from these precursors present high silicon concentration, as determined by Rutherford Backscattering Spectroscopy, the Si content being increased with the temperature of the substrate. The chemical structure was determined by infrared and Raman spectroscopies, from which analyses are deduced the presence of Si–C, C–C and Si–Si bonds and also hydrogen bonded to silicon and carbon atoms. Interpretation of the changes induced by the temperature in the structure and macroscopic properties of the films are also discussed.