Hydrogenated Amorphous Silicon Thin Films as Passivation Layers Deposited by Microwave Remote-PECVD for Heterojunction Solar Cells

An intrinsic silicon thin film passivation layer is deposited by the microwave remote-plasma enhanced chemical vapor deposition at temperature of 175 oC and various gas ratios for solar cell applications. The good quality amorphous silicon films were formed at silane (SiH4) gas flow rates above 15 sccm. The highest effective carrier lifetime was obtained at the SiH4 flow rate of 20 sccm and the value was about 3 times higher compared with the bulk lifetime of 5.6 μs at a fixed injection level of Δn = 5×1014 cm-3. An annealing treatment was performed and the carrier life times were increased approximately 5 times compared with the bulk lifetime. The optimal annealing temperature and time were obtained at 250 oC and 60 sec respectively. This indicates that the combination of the deposition of an amorphous thin film at a low temperature and the annealing treatment contributes to the excellent surface and bulk passivation. KCI Citation Count: 1