The best thing about TOPCon solar cell technology is that the manufacturing process is so similar to PERT solar cells that manufacturers can upgrade their existing production lines with only a small investment. Most manufacturing equipment can remain the same. This makes TOPCon solar cells an excellent investment for manufacturers of PERC/PERT PV modules already in the market.
1. The first step in fabricating TOPCon solar cells is to chemically texturize the wafer surface by using potassium hydroxide (KOH) to remove saw damage during c-Si wafer dicing.
2. After cleaning the wafer, it is formed on the front side of the cell by applying boron tribromide (BBr) using the diffusion method, but then the back side is removed by applying nitric acid and hydrofluoric acid (HF/HNO), and an ultra-thin oxide is produced by wet chemical dipping layer.
3. To grow the nPoly-Si layer, a phosphorus-doped amorphous silicon (n-a-Si:H) layer is grown by a plasma-enhanced chemical vapor deposition (PECVD) process. It is then converted into an nPoly-Si layer after annealing at 900ºC. + +
4. The solar cells are further cleaned and passivation and coatings are applied by PECVD.
5. Finally, the silver/aluminum contacts are coated for metallization by screen printing, using a rapid firing method with a maximum temperature of 760ºC for metallization.
After fabrication of TOPCon solar cells, I-V solar cell curve characterizations were performed to evaluate their performance.
Flow chart
TopCon solar cell technology has a similar structure and manufacturing process to PERC solar cells, with just a few extra steps, we can understand one of his process flow.
