Silicon wafer for solar energy-silicon wafer for solar cells

　　Silicon wafer is one of the important raw materials used in the production of solar photovoltaic cells. The so-called silicon wafer is a process of cutting after single crystal rod and polycrystalline ingot. Usually there are several kinds of silicon wafers, single crystal 125, 156, polycrystalline 125, 156, of which polycrystalline 125 is a square.

　　Production Grade of Solar Silicon Wafers

　　Class A (the highest level of solar wafer production);

　　Grade A-1 (slightly defective);

　　Level 3, B (can be used reluctantly);

　　4. Grade C (can be sliced);

　　Level 5, D (no difference from debris).

　　How to Select Silicon Chips for Solar Cells

　　1. Appearance: There must be no crack, no hard injury, no hole, no edge collapse;

　　2. Physical indicators: Physical indicators include crystal orientation, deviation of crystal orientation, type, thickness, edge length, verticality. The type and orientation of silicon wafer are determined by corresponding measuring instruments, and the thickness, tolerance, edge length, diagonal length, tolerance and perpendicularity of 5 points are measured by corresponding measuring instruments. The most important thing is to check the thickness and thickness variation of silicon wafer (TTV). When the minimum thickness is lower than the initial production, the fragmentation rate will increase. In addition, the content of carbon and oxygen is very important for the quality of silicon wafers, so it is necessary to carry out spot testing.

　　3. Electrical indicators: mainly the minority electron lifetime and resistivity of silicon wafer, the grade of silicon wafer is determined by these two indicators. For example, the minority carrier lifetime and resistivity of grade A single crystal silicon wafers are required to be greater than 10_s and 0-6_.cm.