Deposition of Microcrystalline Silicon Thin Films for Solar Cells by VHF-PECVD

摘要

Intrinsic microcrystalline silicon has been deposited by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) technique at different discharge powers and silane concentrations. The results of Raman evidently show that the transition of materials from amorphous to microcrystalline silicon with the discharge power from low to high. To fabricate microcrystalline silicon material, the lower SC needs lower power and the higher SC needs higher power. The results of photo thermal deflection (PDS) measurements also indicate that the high quality of microcrystalline silicon was fabricated because of the low 'sub-band' absorption coefficient, which is generally associated with defect densities. In addition, the results of dark conductivity and photosensitivity also evidently proved that a number of high quality microcrystalline silicon could be deposited by the optimization of experimental parameters. The results of active energy also show that material deposited by us could be used to fabricate solar cells. Preliminary results on the devices are presented: efficiency of approximately 5.3% was reached for 1 μm thick solar cells.