Nanocrystalline silicon film grown by LEPECVD for photovoltaic applications

This work deals with the characterization of nanocrystalline (nc) silicon films, grown using
the plasma enhanced chemical vapour deposition (PECVD) process based on a lowvoltage-
high-current arc discharge plasma named LEPECVD (low-energy PECVD).
The structural, electrical and chemical properties of the LEPECVD grown films have been
studied as a function of the deposition parameters (substrate temperature, growth rate, silane
dilution). The results show that the films consist of elongated nanocrystals along the
/11 1Sdirection, embedded in an amorphous matrix. The crystallite size along the /1 11S
direction is in the range of 9-20 nm. The volume fraction of crystallinity (wc) varies between
51% and 78%, depending on preparation conditions. Conductivity values of the order of
106O1 cm1 for the layers were measured, making the material suitable for the p-i-n
junction application.