Evaluation of the Burnout Phase of the Contact Firing Process for Industrial PERC

In this work, we investigated the burnout phase of the firing process for industrial monofacial p-type Cz PERC type solar cells by varying the burnout phase thermal budget. The burnout phase was investigated regarding potential thermal budget reduction without performance loss and influence on contact formation. Within this research, the burnout phase does seem to have an influence on contact formation, as higher thermal budget seems to result in an increased thickness of the interfacial glass layer at the front side metal-semiconductor contact. The latter trend is assumed to happen due to increasing glass accumulation via decreasing glass viscosity with higher burnout temperature and longer accumulation time with higher burnout duration. With higher thermal budget, the increasing glass layer thickness seems to cause an increasing series resistance and decreasing solar cell conversion efficiency - although rather slightly within this research -, in turn. This investigation shows that the thermal budget and process energy can be potentially reduced up to half while the wafer throughput can be potentially increased up to double without performance loss.