Technology Outline (Process Description)

“Passivated Emitter and Rear Contact” solar cells, known as PERC solar cells, has rapidly gained market share in the PV industry and became dominating technology. The major advantages of the PERC over the Al-BSF cell are reduced rear-surface recombination and improved rear surface reflectivity. p‐type CZ wafers (180 μm) was taken and processed through damage etching, alkaline texturing, and RCA cleaning, homogeneous emitter is diffused in a liquid POCl₃ diffusion tube. The PSG layer is removed in 5% HF solution. RIE have been used to polish the rear side of the wafer followed by KOH treatment for removal of damage instead of Single Side etcher polishing. AlO_x have been deposited through PECVD. SiNx has been deposited both surface (Top and Rear) through PECVD route as ARC and capping layer respectively. IR laser (1024nm) has been used instead of green laser (532nm) to carry out the laser ablation of stacked dielectric layer followed by KOH treatment in order to remove the laser damage. Metallization has been done by screen printing technology.