Preparation of Al-doped hydrogenated nanocrystalline cubic silicon carbide by VHF-PECVD for heterojunction emitter of n-type crystalline silicon solar cells

Al-doped p-type hydrogenated nanocrystalline cubic silicon carbide (nc-3C-SiC:H) thin films were successfully deposited by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) using dimethylaluminum hydride (DMAH) as an Al source. A high dark conductivity of 6.88×10−4 S/cm was obtained for a 27 nm-thick film under high H2/MMS and plasma power conditions. We applied this optimized film to a heterojunction emitter of n-type c-Si solar cells. The solar cell showed high fill factor of 0.756. The internal quantum efficiency in the short wavelength region was improved to 0.87 with decreasing the thickness of a buffer layer.

► Highly conductive p-type nc-3C-SiC:H thin films were prepared by VHF-PECVD. ► Electrical properties drastically improved by increasing hydrogen dilution ratio. ► Al atoms in the film formed Al–C–O bondings and there is no metallic Al. ► This p-type nc-3C-SiC:H emitter improved the IQE of heterojunction c-Si solar cells.