n-Type, ion implanted silicon solar cells and modules

Summary form only given. This paper describes ion-implanted, screen-printed, high efficiency, stable, n-base silicon cells fabricated from readily available 156 mm n-Cz wafers, along with prototype modules assembled from such cells. Two approaches are described. The first approach, which involves a single phosphorus implant, has been used to produce cells (239 cm²) having a tight distribution of J_sc, V_oc, and FF over a wide range of wafer resistivity (factor of 10), with Fraunhofer-certified efficiencies up to 18.5%. In spite of the full screen-printed and alloyed Al back, a method has been developed for soldering such cells in a module. The second approach, which involves implanting both phosphorus for BSF and boron for front emitter, has been used to produce n-base cells having local back contacts and dielectric (SiN_x/SiO₂) surface passivation. Efficiencies up to 19.1%, certified by Fraunhofer, have been realized on 239 cm² cells.