Laser Assited Doping for Photovoltaic Applications

We successfully demonstrate, incorporation of phosphorus and boron in silicon using an IR semiconductor diode laser (=940 nm) in ambient air. Commercially available transparent spin on dopants were used to obtain surface concentrations higher than 5 x 10 19 atoms/cm 3 with junction depths ranging from 20 nm to 3 microns at laser operating powers of 25-39 Watts. Sheet resistances values of ~5 ohms / sq were observed for both p type and n type doping. It was also observed that the crystalline nature of the silicon was preserved and the surface remained smooth.