Amorphous Silicon-germanium Thin Films Prepared By VHF-PECVD

Compared to the amorphous Si:H thin film material with taebler-Wronskieffects(light-induced degradation effect), the silicon germanium film, as a narrow bandgap material,has the ability to increase the absorption of solar and improve the conversionefficiency of the solar cells. Due to the requirement of low cost, high efficiency, energysaving, the silicon germanium has gradually been in a hot research.The silicon germanium film was prepared with SiH4+GeH4and H2by VHF-PECVD.The microstructure and the properties of films were researched with the substratetemperature,discharge powers,reactive pressure,hydrogen dilution ratio and gasconcentrations, trying to finding the optimal conditions of preparing the silicongermanium film and improving the parameters.After the experimental sample preparation and test analysis, the results showed thatthe excellent hydrogenated microcrystalline silicon germanium film with0.45nm/sdoposition rate,10-9-10-7S/cm optical conductivity,10-9-10-5S/cm dark conductivity and102-103photosensitivity was obtained with5%GeH4concentration, hydrogen dilutionratio of96%, substrate temperature between350℃to400℃, discharge power of40W,deposition pressure of100Pa.