Effects of low-temperature annealing phosphorous gettering process on the electrical properties of multi-crystalline silicon with a low minority carrier lifetime

Abstract

A new low-temperature annealing phosphorous gettering process (LTAPGP) was developed to improve the electrical properties of multi-crystalline silicon which has a low minority carrier lifetime. LTAPGP combined a multi-plateau temperature phosphorous gettering process and a low-temperature annealing process. LTAPGP can remove the iron impurities and crystallographic defects of multi-crystalline silicon, and improve the electrical properties of silicon solar cells that were produced from low minority carrier lifetime silicon wafers. Compared with multi-plateau and two-plateau temperature phosphorous gettering process, LTAPGP was more effective in gettering iron impurities and repairing crystallographic defects. The multi-crystalline silicon wafers with a low minority carrier lifetime went through an LTAPGP process were utilized to produce solar cells. The IV-measurement data prove that the efficiency of the new solar cells is 0.2% higher than that of specimens subject to the multi-plateau and two-plateau temperature processes. The results indicat that LTAPGP can make the low minority carrier lifetime silicon wafers to be used in solar cell industry, improve the utilization ratio and reduce the production cost of cast polysilicon.