Thin polycrystalline silicon films on glass substrates deposited by CVD at intermediate temperatures

BUDINI, N.; BUITRAGO, R. H.; SCHMIDT, J. A.; RISSO, G.; RINALDI, P.; ARCE, R. D.

Valencia

Conferencia; 25th European Photovoltaic Solar Energy Conference and Exhibition; 2010

WIP

We worked on the solid phase epitaxial crystallization of a lightly boron doped (p–) silicon layer on a heavily phosphorous doped (n+) polycrystalline emitter seed layer. Nickel-induced crystallization and post-crystallization doping of intrinsic amorphous silicon thin films (~200 nm) were used to prepare the seed layer. Optical microscopy revealed a solid phase epitaxial growth, with grains growing in a columnar structure. UV reflectance measurements indicated that the films have a crystallinity fraction over 70 % after full crystallization. X-ray diffraction allowed us to analyze also the crystallinity of the final structure and the orientation of the crystals. Considering the design of a solar cell, we propose to obtain a polycrystalline silicon solar cell in a two step process: (1) the Ni-induced crystallization and subsequent doping of the emitter used as a seed layer (n+); (2) the deposition and solid epitaxial growth of the absorber and back surface field layers (p–/p+) onto the emitter.