High-purity germanium single crystal quality detection method

Abstract

The high-purity germanium single crystal quality detection method comprises the following steps: S1, sampling the tail parts of qualified sections of shallow-energy-level impurities, deep-energy-level impurities and crystal defects of high-purity germanium single crystals; s2, sequentially performing grinding, polishing, annealing and liquid nitrogen soaking on the sample wafer; s3, after liquid nitrogen soaking is finished, performing XRT test on the (400) crystal face on the central position and the edge position of the sample wafer to obtain X-ray diffraction patterns of the (400) crystal face at the central position and the edge position of the sample wafer; and S4, based on the X-ray diffraction pattern of each (400) crystal face, determining whether the diffraction peak of the (400) crystal face is a plurality of diffraction peaks or a single diffraction peak, if the diffraction peak is a plurality of diffraction peaks, determining that the quality of the germanium single crystal is poor, and if the diffraction peak is a single diffraction peak, calculating the half-peak width. According to the quality detection method for the high-purity germanium single crystal, the quality of the high-purity germanium single crystal can be detected and evaluated, and then a performance analysis basis is provided for a high-purity germanium detector prepared from the high-purity germanium single crystal.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of germanium crystals, and more particularly to a high-purity germanium single crystal quality detection method. BACKGROUND

[0002] High-purity germanium crystal (i.e. high-purity (13N) germanium single crystal) is the core material for manufacturing high-purity germanium detectors, which are widely used in the fields of nuclear physics, particle physics, astrophysics, nuclear safety and national defense. In the process of manufacturing high-purity germanium detectors, it is found that in addition to the shallow level impurities, deep level impurities and crystal defects of high-purity germanium single crystal affecting the performance of high-purity germanium detectors, the quality of high-purity germanium single crystal also affects the performance of high-purity germanium detectors. Therefore, it is necessary to develop a high-purity germanium single crystal quality detection method. SUMMARY

[0003] In view of the problems in the background art, an object of the present disclosure is to provide a high-purity germanium single crystal quality detection method which can detect and evaluate the quality of high-purity germanium single crystal, and further provide performance analysis basis for high-purity germanium detectors prepared from high-purity germanium single crystal.

[0004] Therefore, a high-purity germanium single crystal quality detection method includes the following steps: S1, sampling a tail piece of a qualified section of shallow level impurities, deep level impurities and crystal defects of high-purity germanium single crystal; S2, the sample piece is sequentially ground, polished, annealed and immersed in liquid nitrogen; S3, after the liquid nitrogen immersion is completed, the center position and the edge position of the sample piece are subjected to (400) crystal plane XRT test, and (400) crystal plane X-ray diffraction patterns of the center position and the edge position of the sample piece are obtained; S4, based on the (400) crystal plane X-ray diffraction patterns, it is confirmed whether the diffraction peak of the (400) crystal plane is multiple or single, if it is multiple, it is determined that the quality of the germanium single crystal is poor, and if it is single, the half peak width is calculated.

[0005] The present disclosure has the following beneficial effects: through the high-purity germanium single crystal quality detection method according to the present disclosure, the quality of high-purity germanium single crystal can be detected and evaluated, and further performance analysis basis for high-purity germanium detectors prepared from high-purity germanium single crystal can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 is a case where the diffraction peak of the (400) crystal plane of a sample piece of a high-purity germanium single crystal detected in Example 1 is multiple diffraction peaks.

[0007] Figure 2 is a case where the diffraction peak of the (400) crystal plane of a sample piece of another high-purity germanium single crystal detected in Example 2 is a single diffraction peak.

[0008] Figure 3This is the case where the diffraction peak of the (400) crystal plane of another high-purity germanium single crystal sample tested in Example 3 is a single diffraction peak.

[0009] Figure 4 This is the case where the diffraction peak of the (400) crystal plane of another high-purity germanium single crystal sample tested in Example 4 is a single diffraction peak. Detailed Implementation

[0010] It will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.

[0011] [Quality Testing Methods for High-Purity Germanium Single Crystals]

[0012] The method for testing the quality of high-purity germanium single crystals according to this disclosure includes the following steps:

[0013] S1 is a sample taken from the tail end of the qualified section of shallow energy level impurities, deep energy level impurities, and crystal defects in a high-purity germanium single crystal.

[0014] S2, the sample is successively ground, polished, annealed and immersed in liquid nitrogen;

[0015] S3. After the liquid nitrogen immersion is completed, XRT tests of the (400) crystal plane are performed on the center and edge positions of the sample to obtain the X-ray diffraction patterns of the (400) crystal plane at the center and edge positions of the sample.

[0016] S4. Based on the X-ray diffraction patterns of each (400) crystal plane, confirm whether the diffraction peak of the (400) crystal plane is a multiple diffraction peak or a single diffraction peak. If it is a multiple diffraction peak, determine that the germanium single crystal is of poor quality. If it is a single diffraction peak, calculate the half-peak width.

[0017] In the high-purity germanium single crystal quality testing method according to this disclosure, step S2 is set based on the fact that when high-purity germanium single crystals are used to make high-purity germanium detectors, the high-purity germanium single crystals need to undergo Li diffusion and are used under liquid nitrogen conditions. The sample processing in step S2 simulates the conditions of high-purity germanium detectors, and the single crystal quality determined in this way is more in line with the manufacturing and use conditions of high-purity germanium detectors.

[0018] In the high-purity germanium single crystal quality testing method according to the present disclosure, in step S3, the (400) crystal plane is a high-index crystal plane with a large diffraction angle (2θ) and a small corresponding interplanar spacing (d-spacing). It is more sensitive to crystal defects, has high angular resolution, reduces peak overlap, and is suitable for evaluating the perfection of the single crystal. Therefore, the full width at half maximum (FWHM) of the (400) diffraction peak can reflect the crystallization integrity of the high-purity germanium single crystal.

[0019] In the high-purity germanium single crystal quality testing method according to the present disclosure, step S3 involves performing XRT testing on the (400) crystal plane at the center and edge positions of the sample. By comparing the X-ray diffraction patterns of the (400) crystal plane at the two positions, the uniformity of the high-purity germanium single crystal quality can be further evaluated in the case of a single diffraction peak.

[0020] Therefore, by using the high-purity germanium single crystal quality testing method according to this disclosure, the quality of high-purity germanium single crystals can be detected and evaluated, thereby providing a basis for performance analysis of high-purity germanium detectors prepared from high-purity germanium single crystals.

[0021] In step S1, shallow-level impurities are detected by Hall effect to determine carrier concentration, with a carrier concentration ≤ 2E10cm⁻¹. -3 As a standard for qualification, the Hall effect test sample collection test can be performed in accordance with CN115825682A.

[0022] In step S1, the crystal defect sampling test and the qualification criteria refer to CN114088707A.

[0023] In step S1, the sampling and testing of deep-level impurity content can be referenced in CN115825682A. For example, for p-type high-purity germanium single crystals, the deep-level impurity content (i.e., deep-level impurity concentration) ≤ 4.5E+09cm⁻¹ -3 For n-type high-purity germanium single crystals, the deep-level impurity content is <5.0E+08cm. -3 .

[0024] In step S1, for example, the sample is a circular piece with a thickness of 0.5-1 mm and a diameter of 30-120 mm.

[0025] In step S2, for example, the grinding process is as follows: grinding is performed using a diamond liquid prepared with 5μm diamond powder and pure water until the roughness is less than 5μm. For example, the mass ratio of diamond powder to pure water is 1:(2-4).

[0026] In step S2, for example, the polishing process is as follows: polishing is performed using a diamond solution prepared with diamond powder no larger than 0.5 μm and pure water until the roughness is less than 50 nm. For example, the mass ratio of diamond powder to pure water is 1:(2-4).

[0027] In step S2, in one example, the annealing process is: 1×10 at 300-400℃ -2 Vacuum annealing for 30-60 minutes.

[0028] In step S2, in one embodiment, the liquid nitrogen is used for immersion for 30-60 minutes.

[0029] [test]

[0030] Example 1

[0031] Example 1 uses the following steps:

[0032] S1 is a sample taken from the tail end of the qualified section of a high-purity germanium single crystal, including shallow-level impurities, deep-level impurities, and crystal defects.

[0033] in,

[0034] The high-purity germanium single crystal was a p-type 13N germanium single crystal obtained by the Czochralski method.

[0035] Shallow level impurities are detected by Hall effect measurement of carrier concentration; carrier concentration ≤

[0036] 2E10cm -3 As a standard for qualification, the Hall effect test sample testing shall be conducted in accordance with CN115825682A.

[0037] Crystal defect sampling and testing, and acceptance criteria, refer to CN114088707A.

[0038] The sampling and testing of deep-level impurity content shall be conducted in accordance with CN115825682A, and the deep-level impurity content (i.e., deep-level impurity concentration) shall be ≤4.5E+09cm. -3 To be qualified,

[0039] The sample is a circular piece with a thickness of 0.75 mm and a diameter of 75 mm;

[0040] S2, the sample is sequentially ground, polished, annealed, and immersed in liquid nitrogen.

[0041] in,

[0042] The grinding process is as follows: use diamond liquid prepared by mixing 5μm diamond powder and pure water at a mass ratio of 1:3 to grind until the roughness is less than 5μm;

[0043] The polishing process is as follows: polishing is performed using a diamond liquid prepared by mixing 0.5μm diamond powder and pure water at a mass ratio of 1:3 until the roughness is less than 50nm.

[0044] The annealing process is as follows: 1×10 at 350℃ -2 Vacuum annealing for 45 minutes;

[0045] Immerse in liquid nitrogen for 45 minutes;

[0046] S3. After the liquid nitrogen immersion is completed, XRT tests of the (400) crystal plane are performed on the center and edge positions of the sample to obtain the X-ray diffraction patterns of the (400) crystal plane at the center and edge positions of the sample.

[0047] S4. Based on the X-ray diffraction patterns of each (400) crystal plane, confirm whether the diffraction peak of the (400) crystal plane is a multiple diffraction peak or a single diffraction peak. If it is a multiple diffraction peak, determine that the germanium single crystal is of poor quality. If it is a single diffraction peak, calculate the half-peak width.

[0048] Example 2

[0049] Except for the fact that the high-purity germanium single crystal in step S1 came from another batch, the rest is the same as in Example 1.

[0050] Example 3

[0051] Except for the fact that the high-purity germanium single crystal in step S1 comes from another batch, the rest is the same as in Example 1.

[0052] Example 4

[0053] Except that the high-purity germanium single crystal in step S1 comes from another batch, the rest is the same as in Example 1.

[0054] Figure 1 The diffraction peaks of the (400) crystal plane of a high-purity germanium single crystal sample tested in Example 1 show that both the diffraction peaks at the center and the edge are two diffraction peaks, indicating that the diffraction peaks are split. This indicates that the quality of the high-purity germanium single crystal is poor and the Czochralski method for growing high-purity germanium single crystals needs to be improved.

[0055] Figure 2 The diffraction peak of the (400) crystal plane of another high-purity germanium single crystal sample detected in Example 2 is a single diffraction peak with an edge half-width of 0.0140 and a center half-width of 0.0115, which differs from the other by 0.0025.

[0056] Figure 3 The diffraction peak of the (400) crystal plane of another high-purity germanium single crystal sample tested in Example 3 is a single diffraction peak with an edge half-width of 0.0180 and a center half-width of 0.0124, which differs from each other by 0.0056.

[0057] Figure 4 The diffraction peak of the (400) crystal plane of another high-purity germanium single crystal sample tested in Example 4 is a single diffraction peak with an edge half-width of 0.0110 and a center half-width of 0.0078, which differs from the edge half-width of 0.0032.

[0058] from Figures 2 to 4 It can be seen that the high-purity germanium single crystal in Example 4 has the narrowest half-width at half-maximum (WHM), while the difference in WHM between Example 2 and Example 4 is the smallest.

[0059] Several exemplary embodiments have been described in detail above, but this document is not intended to limit itself to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.

Claims

1. A method for quality testing of high-purity germanium single crystals, characterized in that, Including the following steps: S1 is a sample taken from the tail end of the qualified section of shallow energy level impurities, deep energy level impurities, and crystal defects in a high-purity germanium single crystal. S2, the sample is successively ground, polished, annealed and immersed in liquid nitrogen; S3. After the liquid nitrogen immersion is completed, XRT tests of the (400) crystal plane are performed on the center and edge positions of the sample to obtain the X-ray diffraction patterns of the (400) crystal plane at the center and edge positions of the sample. S4. Based on the X-ray diffraction patterns of each (400) crystal plane, confirm whether the diffraction peak of the (400) crystal plane is a multiple diffraction peak or a single diffraction peak. If it is a multiple diffraction peak, determine that the germanium single crystal is of poor quality. If it is a single diffraction peak, calculate the half-peak width.

2. The method for detecting the quality of high-purity germanium single crystals according to claim 1, characterized in that, In step S1, the sample is a circular piece with a thickness of 0.5-1 mm and a diameter of 30-120 mm.

3. The method for detecting the quality of high-purity germanium single crystals according to claim 1, characterized in that, In step S2, the grinding process is as follows: grinding is performed using diamond liquid prepared with 5μm diamond powder and pure water until the roughness is less than 5μm.

4. The method for detecting the quality of high-purity germanium single crystals according to claim 3, characterized in that, The mass ratio of diamond powder to pure water is 1:(2-4).

5. The method for detecting the quality of high-purity germanium single crystals according to claim 1, characterized in that, In step S2, the polishing process is as follows: polishing is performed using diamond powder with a diameter of no more than 0.5 μm and pure water to prepare diamond liquid until the roughness is less than 50 nm.

6. The method for detecting the quality of high-purity germanium single crystals according to claim 4, characterized in that, The mass ratio of diamond powder to pure water is 1:(2-4).

7. The method for detecting the quality of high-purity germanium single crystals according to claim 1, characterized in that, In step S2, the annealing process is as follows: 1×10 at 300-400℃ -2 Vacuum annealing for 30-60 minutes.

8. The method for detecting the quality of high-purity germanium single crystals according to claim 1, characterized in that, In step S2, the sample is immersed in liquid nitrogen for 30-60 minutes.

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