摘要： We develop processes for advanced phosphorus doping profiles in order to reduce the emitter saturation current density Jo,e of industrial bifacial PERC+ solar cells. With an in-situ oxidation, which takes place in the POCl3 furnace in between the deposition and the drive-in step, the surface concentration was lowered from 3 × 1020 cm-3 to 1.7 × 1020 cm-3. With an additional ex-situ oxidation, which takes place after the phosphorus silicate glass is removed, the phosphorus surface concentration was further reduced to 3 × 1019 cm- 3. The decreased phosphorus surface concentration drastically reduces Jo,e from 106 fA/cm2 down to 22 fA/cm2. The reduced Jo,e increases the implied open circuit voltage up to 712 mV of unmetallized PERC+ test structures and the Voc of PERC+ solar cells up to 678 mV and efficiencies up to 21.8%. However, our solar cell analysis reveals for the first time, that with increasing thermal budget of the applied POCl3 and oxidation recipes the pseudo fill factor (pFF) decreases by up to 1.5%. This corresponds to an efficiency loss of approximately 0.5%abs. We analyse the pFF loss based on different lifetime test structures representing the emitter or the bulk of the PERC+ solar cell. From the lifetime measurements we calculate I-V curves representing the implied fill factor (iFF) of the different parts of the PERC+ solar cell as well as a combined one for the whole cell, which compares well to the measured pFF. The iFF values clearly show that the pFF is mainly limited by wafer bulk material. However, also the iFF values of the emitter slightly decrease with increasing thermal budget.