Synthesis of novel p-type nanocrystalline silicon from SiH2Cl2 and SiCl4 by rf plasma-enhanced chemical vapor deposition

A novel p-type hydrogenated chlorinated nanocrystalline silicon (nc-Si:H:(Cl)) film was fabricated from chlorinated materials, i.e., SiH2Cl2 and SiCl4, by rf plasma-enhanced chemical vapor deposition. These p-type nc-Si:H:(Cl) films showed high conductivities of 10–50 S/cm under 3000–5000 ppm B2H6 mixing concentrations with lower optical absorption in the visible region, while maintaining a high film crystallinity. The origin of the low optical absorption in p-type nc-Si:H:(Cl) is demonstrated as a function of the B2H6 mixing concentration. The residual H and Cl are accumulated in amorphous silicon phase incorporated in nc-Si:H:(Cl), which results in the lower optical absorption in spite of having a high film crystallinity.