Understanding the sprayed boric acid method for bulk doping of silicon ribbons

The sprayed boric acid (SBA) method for bulk doping of silicon ribbons is investigated. Experimental procedures and main results are reviewed. Computational fluid dynamics and experimental tests using partial spraying suggest the role of gas transported evaporated boron oxide to explain the boron incorporation profiles along the sample. The industrial applicability of the SBA method is discussed.

► Results of a bulk doping method suited for silicon ribbons for photovoltaic applications are presented.
► The method is based on the spraying of the ribbon with boric acid followed by a zone melting recrystallization.
► Experimental results are compared with furnace atmosphere computer modeling.
► Results suggest that doping occurs via two mechanisms: solid diffusion and contamination from gas phase.
► The method is easily controllable and compatible with a continuous industrial process.