Metal-induced growth of poly-Si on foreign substrates for solar cell applications

A new technological method of producing 0.5-6 μm thick device-quality poly-Si films at temperatures below 600°C has been developed. The technique relies on the epitaxial columnar growth of the Si crystals on the lattice-matching NiSi₂ formed as a result of the Si deposition on a Ni prelayer, whose thickness is shown to influence the Si structure. The Si was sputtered onto the heated substrate which was previously coated with 25 nm of Ni. Such metal-induced growth (MIG) of polysilicon is proven to be applicable to a variety of inexpensive, lightweight foreign substrates, with Ni disilicide providing a good back ohmic contact to the Si film. The MIG-diode performance is promising for solar cell applications