Microcrystalline Silicon Solar Cells Deposited at High Rates in a Single Chamber

Hydrogenated microcrystalline silicon(μc-Si:H) thin films with deposition rate of over 2 nm/s were prepared by very high frequency plasma-enhanced chemical vapor deposition under high working pressure and high power, using a shower-head cathode. The effects of working pressure and electrode distance on the microcrystalline silicon growth rate and crystallization fraction were studied. We found that thin films with high deposition rate (Rd) and simultaneously proper crystallization fraction could be obtained only when these two parameters have good matches. After that, the intrinsic layer was further optimized by modifying silane concentration. The performance of solar cells was improved by controlling the silane input time which reduced the incubation layer thickness and then improved the quality of the p/i interface. After this initial optimization, a μc-Si:H singlejunction p-i-n solar cell with the conversion efficiency of 5.3% was deposited at the Rd of 2 nm/s in a single chamber.