GB/T 37051-2018Test method for determination of crystal defect density in PV silicon ingot and wafer (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This standard specifies the method for determining the crystal defect density of solar grade polycrystalline silicon ingots and silicon wafers, including method summary, reagents and materials, and instruments.

And equipment, sample preparation, test procedures, data processing, precision, interference factors, and reporting.

This standard is applicable to the determination of the defect density of solar grade polycrystalline silicon ingots and silicon wafers.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 6379.2-2004 Accuracy of measurement methods and results (accuracy and precision) Part 2: Determination of standard measurement Basic method of repeatability and reproducibility

GB/T 25915.1-2010 Clean rooms and related controlled environments - Part 1: Air cleanliness

GB/T 29054 solar grade cast polycrystalline silicon block

GB/T 29055 solar cell wafer

3 Method summary

Polishing the surface of the silicon wafer with a mixture of nitric acid and hydrofluoric acid, and etching the silicon wafer with a mixture of potassium dichromate and hydrofluoric acid, silicon crystal Defects are preferentially etched, and the surface of the sample is observed using a microscope to observe the crystal defect characteristics of the silicon wafer and count the defects.

By sampling silicon wafers at different positions, the crystal defect density of silicon wafer samples at different locations is measured, and the final result can be obtained. To characterize the crystal defect density of a silicon ingot.

4 Reagents and materials

4.1 Potassium dichromate. analytically pure.

4.2 Hydrofluoric acid. 40% mass fraction, electronic grade.

4.3 Nitric acid. mass fraction of 65%, electronic grade.

4.4 Chemical etching polishing solution. V hydrofluoric acid : V nitric acid = 1:4.

4.5 Deionized water. Conductivity is less than or equal to 1 µS/cm.

4.6 Anhydrous ethanol. Density 0.79g/mL, analytically pure.

4.7 Potassium dichromate solution. mass concentration 44g/L. Weigh 44g of potassium dichromate in a beaker, completely dissolve it with deionized water, and then move in In a 1000 mL volumetric flask, dilute to the mark with deionized water and mix.

4.8 Secco etching solution. a mixture of hydrofluoric acid and potassium dichromate solution, V hydrofluoric acid : V potassium dichromate solution = 2:1.

4.9 Compressed air or nitrogen.