Silicon wafers are the main raw material for solar cell production. At present, they account for nearly 70-80% of the total cost, which belongs to large-scale transactions. Therefore, it is particularly cautious to purchase silicon wafers; if it is inadvertent, it will bring a lot to the company. Big loss. So how can we buy the corresponding grade of qualified silicon, without being deceived? The following is for reference only
The above indicators need to determine the instruments and meters such as low life tester, four-probe tester, etc., if the manufacturers do not have their own, you can commission a number of professional institutions such as the Chinese Academy of Sciences Electrician, 18, measuring institutes and other measurements.
Finally, looking at the electrical indicators, mainly the minority life and resistivity, the level of silicon is mainly determined by these two indicators. For example, the current life expectancy of A-grade single-crystal silicon chips is greater than 10μs and the resistivity is 0-6Ω.cm.
First look at the appearance, must be no cracks, no hard wounds, no holes, no breakage;
Second, look at physical indicators, physical indicators, including crystal orientation, crystal orientation deviation, type, thickness, side length, verticality, and so on. Determine the type, crystal orientation, etc. with the corresponding test equipment; measure 5 thicknesses, tolerances, side lengths and diagonal lengths and tolerances, and verticality with corresponding measuring instruments. Here is the most important aspect for the solar cell process. Silicon wafer thickness and thickness variation (TTV), because many solar cell production lines are required by the thickness of the silicon wafer, and below the minimum thickness for production, the fragmentation rate will increase, and profit will be tossed into the debris. In addition, the carbon and oxygen content is very important for the quality of silicon wafers. It must be tested. Of course, normally, these two indicators will not be a problem. If there is any problem, they will be directly reflected in the electricity mentioned later. Indicators are.
What is a TSA customs lock?
Customs TSA lock means that US Customs transit cargo and baggage transport customs cargo safety testing, the need to ensure universal TSA baggage security and the use of international customs GSM dedicated key.
Why use TSA customs lock?
Starting in January 2003, TSA requires all airport baggage entering the United States must be opened for inspection, but TSA issued a warning: unless TSA certified locks, or do not otherwise be checked baggage unlocked or destroyed by customs have the right to pry check luggage locks.
Benefits Customs TSA lock?
Check how TSA lock Customs: Customs inspector has a TSA lock key hand, be very careful when you open the baggage inspection to ensure safety, but also to re-lock after checking luggage.
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