Laser Annealing of Ion-Implanted CZ Silicon for Solar-Cell-Junction Formation. Final Report

摘要

An investigation was conducted which evaluated the merits of large spot size pulsed laser annealing of phosphorus implanted, Czochralski grown silicon for junction formation of solar cells. The feasibility and requirements were also determined to scale-up a laser system to anneal 7.62 cm diameter wafers at a rate of 1 wafer/second. Laser parameters were developed for optimized performance as substantiated by surface analysis. Functional cells with AM1 conversion efficiencies up to 15.4% for 2 x 2 cm and 2 x 4 cm sizes were attained, and conversion efficiencies ranged up to 14.5% for cells of 7.62 cm diameter. Texture etched surfaces are found incompatible with pulsed laser anneaing due to surface melting. Laser annealed cells are generally found to exhibit conversion efficiencies equal to or better than those of furnace annealed cells. (ERA citation 06:026992)