Characterization of laser-fired contacts processed on wafers with different resistivity

To evaluate the feasibility of transferring the patented Laser-Fired Contact (LFC) process scheme into industrial solar cell production investigations of highly efficient and LFC contacted silicon solar cells on different resistivities have been carried out. These cells feature inverted pyramids on the front side and a thermally grown silicon oxide as surface passivation. Besides the higher efficiencies (up to 21.4% on 0.5 /spl Omega/cm material) of the LFC cells compared to the PERC references (20.9% on 0.5 /spl Omega/cm material), especially the superior value for V/sub oc/ (57.2 mV higher V/sub oc/ on 10 /spl Omega/cm) is an indication for the formation of a local aluminium BSF. The laser alloying process of aluminium into the silicon was studied by L-SNMS measurements and visualised by EBIC scans of solar cell test structures processed on n-type FZ silicon bulk material.