A SIMPLE SINGLE-PHOTOMASK PROCESS FOR FABRICATION OF HIGH-EFFICIENCY MULTICRYSTALLINE-SILICON SOLAR CELLS

摘要

We have developed a simplified process sequence for fabrication of high-efficiency multicrystalline-silicon (mc-Si) solar cells. Photolithography is required only to define the evaporated metal gridlines. We use this fast turn-around, high-yield baseline process to evaluate different mc-Si materials and new processing procedures. The process uses a one-step emitter diffusion/drive-in and an aluminum-alloyed back surface field to provide a well-passivated cell with excellent blue and red response. Laser-scribed cell-isolation grooves are used to define both moderate-area (4, 4.6, or 10.5 cm~2) and large-area (42 cm~2) cells. We have observed minority-carrier diffusion lengths of around 300 μm in 1.4-Ωcm mc-Si material and have achieved efficiencies of 16.8% in 4.6-cm~2 cells. Large-area cell efficiencies in the same material have reached 16.4%.