CN117457523A - Method for detecting minority carrier lifetime of silicon single crystal - Google Patents
Method for detecting minority carrier lifetime of silicon single crystal Download PDFInfo
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- CN117457523A CN117457523A CN202311500431.XA CN202311500431A CN117457523A CN 117457523 A CN117457523 A CN 117457523A CN 202311500431 A CN202311500431 A CN 202311500431A CN 117457523 A CN117457523 A CN 117457523A
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- Prior art keywords
- silicon wafer
- single crystal
- silicon
- minority carrier
- carrier lifetime
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 149
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 148
- 239000010703 silicon Substances 0.000 title claims abstract description 148
- 239000013078 crystal Substances 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 30
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 30
- 238000012545 processing Methods 0.000 claims abstract description 18
- 238000012360 testing method Methods 0.000 claims abstract description 16
- 238000004140 cleaning Methods 0.000 claims abstract description 15
- 238000001514 detection method Methods 0.000 claims abstract description 15
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000001035 drying Methods 0.000 claims abstract description 8
- 238000002791 soaking Methods 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 6
- 238000005530 etching Methods 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 4
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052740 iodine Inorganic materials 0.000 claims description 3
- 239000011630 iodine Substances 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 238000002161 passivation Methods 0.000 claims 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 abstract description 6
- 230000001105 regulatory effect Effects 0.000 abstract description 5
- 238000005215 recombination Methods 0.000 abstract description 3
- 230000006798 recombination Effects 0.000 abstract description 3
- 229910021421 monocrystalline silicon Inorganic materials 0.000 abstract description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000005498 polishing Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000013256 coordination polymer Substances 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000011010 flushing procedure Methods 0.000 description 2
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 2
- 238000012805 post-processing Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/10—Measuring as part of the manufacturing process
- H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
Abstract
The invention provides a detection method for minority carrier lifetime of silicon single crystal, which relates to the technical field of monocrystalline silicon crystal pulling, and comprises the steps of selecting P-or N-type silicon single crystal, slicing the silicon single crystal to obtain an original silicon wafer, putting the original silicon wafer into alkaline corrosive liquid, soaking for a preset time at a preset temperature to generate orthosilicic acid, and obtaining the corroded silicon wafer so as to regulate and control the surface state of the silicon wafer; cleaning the corroded silicon wafer, and drying to obtain a cleaned silicon wafer; and passivating the cleaned silicon wafer, performing a mu PCD method test, wherein the original silicon wafer is in sodium hydroxide corrosive liquid, silicon atoms are combined with hydroxyl groups, unpaired electrons on the silicon wafer can be combined with the hydroxyl groups to form silicon-oxygen bonds, covalent bonds are formed with other atoms after the silicon-oxygen bonds are broken, and finally orthosilicic acid is formed, so that the surface state of the silicon wafer is regulated and controlled, the recombination rate due to the interference of the surface state of the silicon wafer is reduced to the greatest extent when the surface state is passivated again, and the real minority carrier lifetime value of the silicon wafer before processing can be obtained during the test.
Description
Technical Field
The invention belongs to the technical field of monocrystalline silicon detection, and particularly relates to a detection method for minority carrier lifetime of a silicon single crystal.
Background
In a semiconductor silicon single crystal, minority carrier lifetime test is an important detection means for judging whether a P-or N-type product has defects, metal pollution exists or not, and the influence degree on a silicon wafer in the processing process can be judged through the change of a minority carrier lifetime test value. However, in the existing minority carrier lifetime test process, the sample pretreatment mode cannot represent the true value of the minority carrier lifetime of the silicon wafer, so that the influence of the subsequent silicon wafer processing process on the minority carrier lifetime cannot be judged through the change of the minority carrier lifetime test value.
Disclosure of Invention
In view of the above, the present invention provides a method for detecting minority carrier lifetime of a silicon single crystal, which can determine the influence of a processing process on minority carrier lifetime.
The technical scheme adopted for solving the technical problems is as follows:
a method for detecting minority carrier lifetime of silicon single crystal, which carries out minority carrier lifetime detection before processing silicon wafer, comprises the following steps:
s1: selecting P-or N-type silicon single crystal, and slicing the silicon single crystal to obtain an original silicon wafer;
s2: placing an original silicon wafer into alkaline etching solution, and soaking for a preset time at a preset temperature to generate orthosilicic acid to obtain an etched silicon wafer so as to regulate and control the surface state of the silicon wafer;
s3: cleaning the corroded silicon wafer, and drying to obtain a cleaned silicon wafer;
s4: and passivating the cleaned silicon wafer, and testing by a mu PCD method to obtain the minority carrier lifetime of the silicon single crystal.
Preferably, the alkaline etching solution is a sodium hydroxide solution.
Preferably, the concentration of the sodium hydroxide solution is 45% -55%.
Preferably, in the step S2, the predetermined temperature is 70 ℃ or higher.
Preferably, in the step S2, the predetermined time is 5min to 20min.
Preferably, in the step S1, the thickness of the original silicon wafer is less than 400mm.
Preferably, in the step S3, the etched silicon wafer needs to be cleaned for several times, so as to clean the alkaline etching solution and other impurities.
Preferably, in the step S3, the etched silicon wafer is washed with pure water for the last time in a plurality of times of washing.
Preferably, in the step S4, the cleaning silicon wafer is passivated by using iodine.
Preferably, in the step S4, the cleaning silicon wafer is passivated by preparing a heat-treated oxide film on the surface of the cleaning silicon wafer.
Compared with the prior art, the invention has the beneficial effects that:
according to the method for detecting the minority carrier lifetime of the silicon single crystal, P-type or N-type silicon single crystal is selected, the silicon single crystal is sliced to obtain an original silicon wafer, the original silicon wafer is placed into alkaline etching solution, and is soaked for a preset time at a preset temperature to generate orthosilicic acid, so that the etched silicon wafer is obtained, and the surface state of the silicon wafer is regulated and controlled; cleaning the corroded silicon wafer, and drying to obtain a cleaned silicon wafer; and passivating the cleaned silicon wafer, performing a mu PCD method test, wherein the original silicon wafer is in sodium hydroxide corrosive liquid, silicon atoms are combined with hydroxyl groups, unpaired electrons on the silicon wafer can be combined with the hydroxyl groups to form silicon-oxygen bonds, covalent bonds are formed with other atoms after the silicon-oxygen bonds are broken, and finally orthosilicic acid is formed, so that the surface state of the silicon wafer is regulated and controlled, the recombination rate due to the interference of the surface state of the silicon wafer is reduced to the greatest extent when the surface state is passivated again, and the real minority carrier lifetime value of the silicon wafer before processing can be obtained during the test.
Drawings
Fig. 1 is a detection diagram of an embodiment.
Fig. 2 is a second detection diagram of the embodiment.
Fig. 3 is a test chart one of the comparative examples.
Fig. 4 is a detection chart two of the comparative example.
Detailed Description
The technical scheme and technical effects of the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.
A method for detecting minority carrier lifetime of silicon single crystal, which carries out minority carrier lifetime detection before processing silicon wafer, comprises the following steps:
s1: selecting P-or N-type silicon single crystal, and slicing the silicon single crystal to obtain an original silicon wafer;
s2: placing an original silicon wafer into alkaline etching solution, and soaking for a preset time at a preset temperature to generate orthosilicic acid to obtain an etched silicon wafer so as to regulate and control the surface state of the silicon wafer;
s3: cleaning the corroded silicon wafer, and drying to obtain a cleaned silicon wafer;
s4: and passivating the cleaned silicon wafer, and testing by a mu PCD method to obtain the minority carrier lifetime of the silicon single crystal.
Compared with the prior art, the invention has the beneficial effects that:
according to the method for detecting the minority carrier lifetime of the silicon single crystal, P-type or N-type silicon single crystal is selected, the silicon single crystal is sliced to obtain an original silicon wafer, the original silicon wafer is placed into alkaline etching solution, and is soaked for a preset time at a preset temperature to generate orthosilicic acid, so that the etched silicon wafer is obtained, and the surface state of the silicon wafer is regulated and controlled; cleaning the corroded silicon wafer, and drying to obtain a cleaned silicon wafer; and passivating the cleaned silicon wafer, performing a mu PCD method test, wherein the original silicon wafer is in sodium hydroxide corrosive liquid, silicon atoms are combined with hydroxyl groups, unpaired electrons on the silicon wafer can be combined with the hydroxyl groups to form silicon-oxygen bonds, covalent bonds are formed with other atoms after the silicon-oxygen bonds are broken, and finally orthosilicic acid is formed, so that the surface state of the silicon wafer is regulated and controlled, the recombination rate due to the interference of the surface state of the silicon wafer is reduced to the greatest extent when the surface state is passivated again, and the real minority carrier lifetime value of the silicon wafer before processing can be obtained during the test.
Further, the alkaline etching solution is sodium hydroxide solution.
Further, the concentration of the sodium hydroxide solution is 45% -55%.
Further, in the step S2, the predetermined temperature is 70 ℃ or higher.
Further, in the step S2, the predetermined time is 5min to 20min, and the alkaline etching solution with too low temperature and too short time cannot react with the silicon wafer to generate orthosilicic acid, so that the minority carrier lifetime real value of the silicon wafer cannot be detected.
Further, in the step S1, the thickness of the original silicon wafer is smaller than 400mm.
Further, in the step S3, the etched silicon wafer needs to be cleaned for several times, so as to clean the alkaline etching solution and other impurities.
In the step S3, the etched silicon wafer is washed with pure water for the last time during the multiple times of washing.
Further, in the step S4, the cleaning silicon wafer is passivated by using iodine.
Further, in the step S4, the cleaning silicon wafer is passivated by preparing a heat-treated oxide film on the surface of the cleaning silicon wafer.
Example 1
S1: selecting a P-silicon single crystal product, and cutting off a silicon wafer with the thickness of 0.5-3 mm by using a cutting machine to obtain an original silicon wafer;
s2: adding NaOH with the concentration of 49% into an alkali corrosion machine, wherein the solution volume can submerge the whole sample, heating the alkali liquor to 70-90 ℃, placing the original silicon wafer into a basket, placing the basket into the alkali liquor, and soaking for 10min to obtain the corrosion silicon wafer.
S3: after the etched silicon wafer is obtained, the etched flower basket is quickly transferred to a warm water tank with the temperature of 60-80 ℃ to be soaked for 10-30 min; and after the soaking is finished, transferring the corroded basket to a pure water overflow tank for continuous flushing, and finally spin-drying the sample to obtain the cleaned silicon wafer.
S4: placing the cleaned silicon wafer into a furnace body, feeding the silicon wafer into the furnace at 600-700 ℃, raising the temperature to 1000 ℃ at the temperature rising rate of 5 ℃ per minute, keeping the temperature for 10min, lowering the temperature to 700 ℃ at the temperature lowering rate of 3 ℃ per minute, so that a heat treatment oxide film is generated on the surface of the silicon wafer, and testing the silicon wafer by using a mu PCD method to obtain a minority carrier lifetime detection value before processing, as shown in figure 1.
And then carrying out subsequent processing on the silicon wafer: after chamfering, lapping, CP etching, DK/CVD, BSD, and mechanochemical polishing, the surface of the processed silicon wafer was passivated with iodine, and tested by detecting μpcd to obtain a post-processing minority carrier lifetime detection value, as shown in fig. 2.
As can be seen from fig. 1 and 2, the influence of the processing on the minority carrier lifetime of the silicon wafer can be determined by detecting the minority carrier lifetime.
Comparative example:
s1: selecting a P-silicon single crystal product, and cutting off a silicon wafer with the thickness of 0.5-3 mm by using a cutting machine to obtain an original silicon wafer;
s2: the original silicon wafer is put into mixed acid for mirror polishing, and the mixed acid is prepared by the following proportion: hydrofluoric acid 13%: 37% of nitric acid: acetic acid 20%: 30% of water, soaking the silicon wafer in hydrofluoric acid with the concentration of 49% for 10min after polishing, and finally, overflowing the silicon wafer in pure water to obtain the etched silicon wafer.
S3: after the etched silicon wafer is obtained, the etched flower basket is quickly transferred to a warm water tank with the temperature of 60-80 ℃ to be soaked for 10-30 min; and after the soaking is finished, transferring the corroded basket to a pure water overflow tank for continuous flushing, and finally spin-drying the sample to obtain the cleaned silicon wafer.
S4: placing the cleaned silicon wafer into a furnace body, feeding the silicon wafer into the furnace at 600-700 ℃, raising the temperature to 1000 ℃ at the temperature rising rate of 5 ℃ per minute, keeping the temperature for 10min, lowering the temperature to 700 ℃ at the temperature lowering rate of 3 ℃ per minute, so that a heat treatment oxide film is generated on the surface of the silicon wafer, and testing the silicon wafer by using a mu PCD method to obtain a minority carrier lifetime detection value before processing, as shown in figure 3.
And then carrying out subsequent processing on the silicon wafer: after chamfering, lapping, CP etching, DK/CVD, BSD, and mechanochemical polishing, the surface of the processed silicon wafer was passivated with iodine, and tested by detecting μpcd to obtain a post-processing minority carrier lifetime detection value, as shown in fig. 4.
As can be seen from fig. 3 and 4, the minority carrier lifetime value measured before processing is lower than the minority carrier lifetime value after processing in fig. 4, so that the influence of the processing on the minority carrier lifetime of the silicon wafer cannot be judged by the detection of the minority carrier lifetime.
According to the embodiment and the comparative example, the problem that the life of the body cannot be monitored due to the poor surface state of the sample is avoided to the greatest extent through pretreatment, so that the true value of the minority carrier lifetime can be measured, and the influence of subsequent processing on the minority carrier lifetime can be obtained.
The foregoing disclosure is illustrative of the preferred embodiments of the present invention, and is not to be construed as limiting the scope of the invention, as it is understood by those skilled in the art that all or part of the above-described embodiments may be practiced with equivalents thereof, which fall within the scope of the invention as defined by the appended claims.
Claims (10)
1. A method for detecting minority carrier lifetime of silicon single crystal is characterized in that: the minority carrier lifetime detection is carried out before the processing of the silicon wafer, and the method comprises the following steps:
s1: selecting P-or N-type silicon single crystal, and slicing the silicon single crystal to obtain an original silicon wafer;
s2: placing an original silicon wafer into alkaline etching solution, and soaking for a preset time at a preset temperature to generate orthosilicic acid to obtain an etched silicon wafer so as to regulate and control the surface state of the silicon wafer;
s3: cleaning the corroded silicon wafer, and drying to obtain a cleaned silicon wafer;
s4: and passivating the cleaned silicon wafer, and testing by a mu PCD method to obtain the minority carrier lifetime of the silicon single crystal.
2. The method for detecting minority carrier lifetime of silicon single crystal according to claim 1, wherein: the alkaline corrosive liquid is sodium hydroxide solution.
3. The method for detecting minority carrier lifetime of silicon single crystal according to claim 2, wherein: the concentration of the sodium hydroxide solution is 45% -55%.
4. The method for detecting minority carrier lifetime of silicon single crystal according to claim 1, wherein: in the step S2, the preset temperature is above 70 ℃.
5. The method for detecting minority carrier lifetime of silicon single crystal according to claim 1, wherein: in the step S2, the preset time is 5-20 min.
6. The method for detecting minority carrier lifetime of silicon single crystal according to claim 1, wherein: in the step S1, the thickness of the original silicon wafer is smaller than 400mm.
7. The method for detecting minority carrier lifetime of silicon single crystal according to claim 1, wherein: in the step S3, the etched silicon wafer needs to be cleaned for a plurality of times so as to clean alkaline etching liquid and other impurities.
8. The method for detecting minority carrier lifetime of silicon single crystal according to claim 7, wherein: in the step S3, the etched silicon wafer is washed by pure water for the last time in a plurality of times of washing.
9. The method for detecting minority carrier lifetime of silicon single crystal according to claim 1, wherein: in the step S4, when the cleaning silicon wafer is passivated, iodine is used for passivation.
10. The method for detecting minority carrier lifetime of silicon single crystal according to claim 1, wherein: in the step S4, the cleaning silicon wafer is passivated by preparing a heat treatment oxide film on the surface of the cleaning silicon wafer.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311500431.XA CN117457523A (en) | 2023-11-13 | 2023-11-13 | Method for detecting minority carrier lifetime of silicon single crystal |
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| CN202311500431.XA CN117457523A (en) | 2023-11-13 | 2023-11-13 | Method for detecting minority carrier lifetime of silicon single crystal |
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| CN117457523A true CN117457523A (en) | 2024-01-26 |
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| CN202311500431.XA Pending CN117457523A (en) | 2023-11-13 | 2023-11-13 | Method for detecting minority carrier lifetime of silicon single crystal |
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- 2023-11-13 CN CN202311500431.XA patent/CN117457523A/en active Pending
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