Silicon films are largely used as the semiconductor material for photovoltaic effect in solar cells. A thick film is particularly useful because a thicker film can absorb more photons but this in turn increases material cost. Conversely, cells made from thin-films are prone to serious mechanical instabilities. This technology outlines a laser crystallography method that uses thin films to create epitaxially grown ( i.e. crystalline deposited) thick silicon films. As a result, this technology is able to achieve a low defect-density material at low material cost for solar cell production.
This technology comprises of methods and systems for making low defect, large-grained crystalline thick films using an alternative laser-based epitaxial process. In traditional film growth methods, lasers are used to induce full melting of an amorphous layer deposited on a high quality seed layer. This process uses backside irradiation to partially melt a thick silicon amorphous layer to induce a self-sustained "explosive" crystallization process in which heat of fusion is captured in the film to allow for high quality epitaxial growth. The product film is of sufficient (crystalline) quality and is produced using a single laser pulse.
Patent Pending (US 20140045346)
Tech Ventures Reference: IR M08-019