How to choose high quality solar silicon wafer?

1. First look at the appearance, there must be no cracks, no flaws, no holes, no chipping.
2. Secondly, look at the physical indicators. There are many physical indicators, including crystal orientation, crystal orientation deviation, type, thickness, side length, perpendicularity and so on. Use the corresponding testing instruments to determine the type, crystal orientation, etc.; use the corresponding measuring instruments to measure the thickness, tolerance, side length and diagonal length and tolerance, perpendicularity, etc. of 5 points. For the solar cell process, the most important thing is Silicon wafer thickness and thickness variation (TTV), because many solar cell production lines have silicon wafer thickness requirements. If the thickness is lower than the minimum production thickness, the fragmentation rate will increase, and the profit will be tossed into the fragments. In addition, the content of carbon and oxygen is very important to the quality of silicon wafers, so random testing must be carried out. Of course, normally speaking, there will be no problems with these two indicators. If there are problems, they will be directly reflected in the electrical parameters mentioned later. The indicator is in.
3. Finally, look at the electrical indicators, mainly the minority carrier lifetime and resistivity. The grade of silicon wafers is mainly determined by these two indicators. For example, the minority carrier lifetime of A-level monocrystalline silicon wafers is required to be greater than 10μs, and the resistivity is 0-6Ω.cm.