TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The solar cell further comprises an antireflective coating layer disposed on the n-type region.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The aluminum paste composition further comprises an optional additive including glass frits, amorphous silicon dioxide, organometallic compounds, boron-containing compounds, metal salts and/or siloxanes. Preferred Process: The step of applying the aluminum paste composition comprises screen printing the aluminum paste composition on the back-side of the p-type silicon substrate. The step of firing the p-type silicon substrate after the application of the aluminum paste and the step of firing the p-type silicon substrate after the application of the metal paste are done at the same time. Preferred Components: The metal phosphate further comprises a hydrate of the metal phosphate. The metal of the metal phosphate comprises at least one of lithium, sodium, potassium, rubidium, beryllium, magnesium, calcium, strontium, barium, boron, aluminum, gallium, indium, germanium, selenium, tellurium, antimony, bismuth, yttrium, lanthanum, gadolinium, erbium, cadmium, zirconium, nickel, copper and silver. The metal phosphate comprises at least one of bismuth phosphate, magnesium phosphate, strontium phosphate, calcium metaphosphate, calcium pyrophosphate, tin pyrophosphate and/or zinc pyrophosphate. The metal phosphate is present at 0.025-3 wt.%, preferably 0.05-3 wt.% so that the weight ratio of aluminum powder to metal phosphate is 32:1-2000:1. The organic vehicle is present at 20-30 wt.%. The aluminum powder comprises at least one of nodular aluminum, spherical aluminum, flake aluminum and/or irregularly shaped aluminum. The aluminum back electrode further comprises 0.1-10 wt.% of an optional additive including glass frits, amorphous silicon dioxide, metal oxides, boron-containing compounds and/or metal salts. The aluminum back electrode exhibits an electron spectroscopy for chemical analysis phosphorus 2p peak binding energy of 131-136 eV. EXAMPLE - Typical composition comprised of: pre-wet aluminum slurry (obtained by mixing aluminum (80 wt.%) and organic vehicle (including terpineol solvent (43.5 wt.%), dibutyl carbitol (43.5 wt.%), oleic acid (7.5 wt.%) and ethyl cellulose (5.5 wt.%)) (693.8 g); organic vehicle (including terpineol solvent (46.7%), dibutyl carbitol (40.9%) and ethyl cellulose (12.4%)) (18.75 g); epoxidized octyl tallate (3.75 g); oleic acid (2.25 g); and wax/hydrogenated castor oil (7.5 g).