Low temperature deposition of hydrogenated nanocrystalline SiC films by helicon wave plasma enhanced chemical vapor deposition

Abstract

Hydrogenated nanocrystalline silicon carbide (nc-SiC:H) films have been deposited by using helicon wave plasma enhanced chemical vapor deposition technique at low substrate temperature. The influences of radio frequency (rf) power and substrate temperature on the properties of the deposited nc-SiC:H films were investigated. It is found that hydrogenated amorphous SiC films were fabricated at a low rf power, while the nc-SiC:H films with a microstructure of SiC nanocrystals embedded in amorphous counterpart could be deposited when the rf power is 400 W or more. The plasma transition from the capacitive dominated discharge to the helicon wave discharge with high plasma intensity influences the film microstructure and surface morphology. The analysis of the films deposited at various substrate temperatures reveals that the onset of SiC crystallization occurs at the substrate temperature as low as 150 °C. The low temperature deposition of nc-SiC:H films enables the fabrication of silicon-based thin-film solar cells onto flexible plastic substrates using nc-SiC:H film as a window layer.