UPGRADE OF AN INDUSTRIAL Al-BSF SOLAR CELL LINE INTO PERC USING 3600 WAFERS/HOUR ALD Al_2O_3+SiN_x SOLUTION RAMP-UP

摘要

In this paper, we present the results of the upgrade of a standard monocrystalline Aluminum Back Surface Field (Al-BSF) solar cell line to a passivated emitter and rear cell (PERC) solar cell line and ramp-up. Three additional process steps are added: spatial ALD Al_2O_3 using SoLayTec's InPassion ALD, rear side SiN_x capping layer deposited by a direct plasma system, using e.g. Tempress' SPECTRUM, and a laser to open the rear side dielectric layers, using a conventional laser system. The Al_2O_3 post-deposition anneal is integrated into the SiN_x capping layer deposition process. Besides a good PERC solar cell efficiency, also the wafer appearance of these solar cells is essential. The wafer appearance is a combination of scratches, marks and hazing. In this work, the wafer appearance is improved by optimization of the TMA consumption and the temperature of the integrated-Anneal SiN_x (iA-SiN_x) rear side capping recipe while maintaining the solar cell efficiency. Further adjustments are made in order to improve the throughput and reliability of the equipment. This results in a PERC process with a high solar cell efficiency, good wafer appearance and a throughput above 3600 wafers/hour.