Effects of hydrogen dilution and B-doping on the density of Si–C bonds and properties of a-SixC1-x:H films
Keywords:
Plasma-enhanced chemical vapor deposition, hydrogenated amorphous silicon carbon alloy, material propertiesAbstract
This work presents a study on the effects of hydrogen dilution and boron doping on the formation of Si–C and Si–H bonds during the deposition of hydrogenated amorphous silicon carbon alloy films by plasma-enhanced chemical vapor deposition. Low power densities of 25 mW/cm2 and 50 mW/cm2, high pressure of 1.5 Torr, temperatures of 150 °C and 200 °C, and methane-silane gas flow ratios of 0.70 and 0.85 were chosen in order to obtain suitable films for biomedical and biological applications. FTIR spectroscopy, UV-Vis spectroscopy, atomic force microscopy and electrical dark conductivity measurements were carried out to characterize the films. The results show that hydrogen dilution decreases CHn groups in the films and increases the Si–C and Si–H bond densities, whereas B-doping decreases the Si–C and Si–H bond densities. Undoped films with optical band gap of 2.47 eV and conductivity around of 5x10-10 S/cm, and B-doped films with a root mean square roughness of about 1 nm and a conductivity of the order of 10-6 S/cm were obtained.References
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