GB/T 14142-2017Test method for crystallographic perfection of epitaxial layers in silicon—Etching technique (English PDF)

Foreword

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

This standard replaces GB/T 14142-1993 "silicon epitaxial crystal integrity test method corrosion." This standard compared with GB/T 14142-1993, the main technical changes are as follows.

--- revised method summary (see Chapter 4, 1993 edition Chapter 2);

--- Increasing the interference factor (see Chapter 5);

--- Increasing the chromium-free solution and its corrosion method (see 5.2,6.13,9.2.2).

1 Scope

This standard specifies the use of chemical etching display, and the use of metallographic microscope test silicon epitaxial crystal integrity of the method.

This standard applies to silicon epitaxial layer stacking fault stacking and dislocation density test, the silicon epitaxial layer thickness greater than 2µm, the defect density test Range 0 ~ 10000cm-2.

2 Normative references

The following documents for the application of this document is essential. For dated references, only the dated version applies to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 14264 semiconductor materials terminology

GB/T 30453 silicon defects of the original map

3 Terms and definitions

GB/T 14264 and GB/T 30453 defined terms and definitions apply to this document.

4 Method summary

The sample was etched with a mixed solution of chromic acid, hydrofluoric acid or hydrofluoric acid, nitric acid, acetic acid, and silver nitrate. The crystal defects of the epitaxial silicon layer were excellent Corrosion first. By observing the surface of the sample with a microscope, the defect characteristics can be observed and the defects counted.

5 Interference factors

5.1 corrosive liquid placed too long, there is volatility, precipitation phenomenon, affecting the corrosion effect.

5.2 The choice of different etching solution (chromium, chromium-free) may cause some of the silicon epitaxial wafer corrosion effect is different.

5.3 Corrosion time is too short, if the defect characteristics are not obvious, or no pit corrosion, the corrosion time should be extended, while monitoring the silicon epitaxial layer thickness.

5.4 Corrosion time is too long, corrosion pits enlarged, while the surface roughness, the microscope will result in unclear background, defect characteristics are not obvious.

5.5 one-time corrosion of more than 2 epitaxial wafer, easy to cause corrosion temperature, corrosion rate, reactant easily adsorbed on the surface of the sample Subsidence observation, should pay attention to the need to be a one-time corrosion of the epitaxial wafer etching solution ratio.

5.6 Corrosion temperature between the operating room, the amount of corrosion solution ratio will affect the corrosion temperature, corrosion rate, thus affecting the corrosion effect Observed.

5.7 Detection of silicon epitaxial layer thickness of not more than 2µm stacking faults or dislocation defects, you can refer to this standard, the need for careful operation, strict control Corrosion rate.

5.8 Contamination that can not be removed by cleaning or depositing a silicon epitaxial wafer may appear after preferential etching.

5.9 Preferential corrosion, such as the corrosive liquid with insufficient mixing, precipitation may occur, easy and crystal defects confusion.

5.10 Calibration of the field of view of the microscope will directly affect the accuracy of defect density measurement.

5.11 This method of testing, which is based on the assumption of random distribution of defects on the silicon surface, can be used depending on the size and location of the defects […]