CN115876774A - Method for detecting surface dislocation density of c-surface of high-purity sapphire wafer - Google Patents
Method for detecting surface dislocation density of c-surface of high-purity sapphire wafer Download PDFInfo
- Publication number
- CN115876774A CN115876774A CN202111146198.0A CN202111146198A CN115876774A CN 115876774 A CN115876774 A CN 115876774A CN 202111146198 A CN202111146198 A CN 202111146198A CN 115876774 A CN115876774 A CN 115876774A
- Authority
- CN
- China
- Prior art keywords
- sapphire
- etch pits
- detecting
- pits
- test points
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The invention relates to the field of wafer processing, in particular to a method for detecting c-plane dislocation of sapphire, which comprises the following steps: putting the sapphire wafer to be detected into molten potassium hydroxide for corrosion, and observing a corrosion pit on the c surface of the sapphire wafer by using a microscope after cleaning; and selecting N test points on the c surface to shoot corresponding pictures, counting the sapphire etch pits by adopting a method for calculating the area, and calculating the surface dislocation density of the c surface of the sapphire wafer to be detected. The device provided by the invention is low in cost, can be used for rapidly detecting sapphire sheets of enterprises, and is high in precision.
Description
Technical Field
The invention relates to the field of wafer processing, in particular to a method for detecting the c-surface growth dislocation density of a high-purity sapphire wafer.
Background
The sapphire being alpha-Al 2 O 3 Crystals, commonly known as corundum, also known as white gem, are one of the earliest utilized natural minerals by humans. Artificially produced pure alpha-Al 2 O 3 Second to diamond, with a Mohs hardness of 9, and a crystal structure thereofThe oxygen atoms in the alloy are arranged in a mode of approximate Hexagonal Close Packed (HCP), and the aluminum atoms are filled in octahedral coordination among the oxygen atoms and have about 2/3 of gaps, so that the alloy has the advantages of high strength, high hardness, high temperature resistance (the melting point reaches 2050 ℃), strong abrasion resistance, strong corrosion resistance, stable chemical property and the like; it is insoluble in water, is not generally corroded by acid and alkali, and can be corroded by phosphoric acid, hydrofluoric acid or molten potassium hydroxide (KOH) only under a specific high-temperature condition (above 400 ℃); meanwhile, the material has the characteristics of good lattice matching with semiconductor materials such as GaN and the like, high transmittance to light, excellent electrical insulation and the like.
The sapphire is widely applied to military and civil fields such as materials, microelectronics, aerospace industry and the like: such as for the manufacture of rotors, pistons, high pressure sodium tubes, multilayer integrated circuit substrates, multilayer capacitors, microwave devices, LED substrate materials, lasers, chemical sensors, fairings for missile windows and satellites, high mach missile fairings, antenna windows, bioceramics, and the like.
Wherein, the fairing made of sapphire and the optical window are widely applied in the field of military aviation and are the key points of research in many countries in the world; the LED substrate material is an important application object of the sapphire, and according to statistics, the application of the LED substrate material accounts for more than 75% of the demand of the sapphire, and the application of the non-substrate material accounts for about 25%; and every 1% increase in LED illumination penetration will directly pull the growing demand of about 107 thousands of sheets of sapphire substrate. With the rapid growth of the application field of the downstream industry of the LED, the demand of upstream substrate material sapphire is increased.
At present, the technology for preparing sapphire by a kyropoulos method is in the front of the world at home, 450kg of world maximum sapphire is successfully prepared in 2018 by certain inner Mongolia companies, and 400kg of sapphire crystals are industrially produced in high quantity in 2019 by certain Ningxia companies, which are all higher than 350kg reported in Russia in 2017.
However, during the production and processing of sapphire, a certain amount of dislocation is introduced into sapphire due to temperature difference, impurities, seed crystal morphology, uneven stress, environmental factors during use and the like, so that oxygen atoms deviate from HCP arrangement, and the mechanical, chemical, thermodynamic and optical properties of the sapphire finished product are reduced. Therefore, it is necessary to detect the processed sapphire to determine its use value. The method in the prior art mainly carries out point dislocation detection on the surface of the sapphire C surface so as to calculate the dislocation density of the sapphire crystal block, but the counting difficulty of the method is high and the method is inaccurate.
Disclosure of Invention
The invention aims to solve the problem of difficult counting in the existing sapphire c-surface dislocation detection method, and forms a new method for detecting the sapphire c-surface dislocation density by calculating the area of a corrosion region. The method adopts an area counting method during counting, and makes up for the adverse effect of point dislocation in the prior art on the dislocation density counting result of the original sapphire crystal block.
Therefore, the technical scheme of the invention is as follows:
a method of detecting c-plane dislocations in sapphire, comprising the steps of:
s1, corroding a sapphire wafer to be detected in molten potassium hydroxide, and observing a corrosion pit on the c surface of the sapphire wafer by using a microscope after cleaning;
s2, selecting N test points on the c surface to shoot corresponding pictures, calculating the total area of the corrosion pits in the N pictures, and calculating the surface dislocation density of the c surface of the sapphire wafer to be tested.
According to the invention, the step of selecting N test points on the c surface to shoot corresponding pictures specifically comprises the following steps: observing the corrosion pits on the c surface of the sapphire wafer by using a metallographic microscope, selecting N test points with the area of A1 on the c surface, and shooting photos of all the test points;
preferably, N.gtoreq.5, preferably N.gtoreq.8, such as 9, 13; preferably, the N test points are uniformly distributed, for example, uniformly distributed along the center of the c-plane, for example, the N test points are uniformly distributed on a circle centered on the center of the c-plane.
Preferably, the area A1 of each selected test point is 0.005cm 2 -0.05cm 2 Preferably, the area A1 of the test point is 0.01cm 2 -0.04cm 2 E.g. the saidThe area A1 of the test point is 0.02cm 2 -0.03cm 2 。
Preferably, there is at least one etch pit on each of the test points.
According to the invention, the step of calculating the total area of the etch pits in the N pictures and the step of calculating the surface dislocation density of the c surface of the sapphire wafer to be measured specifically comprises the following steps: and calculating the total area A2 of the etch pits in all the test points according to the pictures of the test points, selecting N1 etch pits as standard etch pits, calculating the average area A3 of the standard etch pits, and obtaining the surface dislocation density of the c surface of the sapphire sample according to the ratio of (A2/A3)/(N x A1).
Preferably, N1. Gtoreq.3, preferably N1. Gtoreq.4, for example 5 or 6.
Preferably, the standard etch pits have a regular triangle shape, a deformed polygon with regular edges similar to the regular triangle shape, or a structure with parallel lines spaced by regularly arranged triangles, and preferably, the standard etch pits are solid regular triangle etch pits; preferably, the areas of N1 of said standard etch pits are similar, e.g. not more than 20% apart.
More preferably, the standard etch pits have an area that deviates by no more than 15%, and even more preferably, the standard etch pits have an area that does not exceed 10%.
According to the invention, in step S1, the etching is performed under constant temperature conditions, the etching temperature is 330 ℃ to 400 ℃, the etching time is 10 to 30min, preferably the etching temperature is 350 ℃ to 380 ℃, and the etching time is 15 to 25min, for example 20min.
According to the invention, the etching is carried out in a crucible, for example, the potassium hydroxide is put into the crucible in advance and is heated and melted, and then the c-surface of the sapphire wafer to be tested is put into the crucible facing to the etching solution for etching, preferably, the etching is carried out in high-temperature equipment, such as a muffle furnace or a tube furnace.
According to the invention, the sapphire wafer to be measured is cooled (air-cooled) in air before being cleaned, and the air-cooling time is 30-120s, such as 60s.
According to the invention, the cleaning of the sapphire to be measured comprises the step of cleaning the corroded sapphire by using an acid solution.
Preferably, the acid solution is dilute hydrochloric acid, dilute nitric acid or dilute sulfuric acid, preferably dilute hydrochloric acid, the concentration of the dilute hydrochloric acid is 1% -20%, the dilute hydrochloric acid is configured by adopting concentrated hydrochloric acid and water according to a volume ratio of 1:1-1:5, for example, the concentrated hydrochloric acid and water according to a volume ratio of 1:3. Preferably, an acid solution formulated with a premium grade pure feedstock is used.
According to the invention, after the sapphire is cleaned by using the acid solution, the method also comprises the step of ultrasonic cleaning or cleaning by using a surfactant.
Preferably, the surfactant comprises a surfactant selected from a cationic surfactant, a nonionic surfactant or an amphoteric surfactant or a combination of two or more thereof; preferably, the detergent composition comprises a surfactant selected from sodium linear alkylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, ammonium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl sulfate, lauroyl glutamic acid, polyoxyethylene nonylphenol ether, stearic acid monoglyceride, lignosulfonate, heavy alkylbenzene sulfonate or alkyl sulfonate or a combination of two or more thereof, for example, a detergent solution, a laundry detergent solution.
Preferably, after the surfactant washing, a step of washing with water or an alcohol solution is further included, specifically, the step of washing with purified water, deionized water or methanol is included, and the washing manner is washing or ultrasonic washing, for example, ultrasonic washing with purified water.
According to the invention, the standard etch pits have a structure substantially as shown in fig. 2.
According to the invention, the metallographic microscope has a magnification of 50 to 500 times, more preferably a magnification of 100 times; preferably, the camera photograph exceeds 2,000,000 pixels.
According to the invention, the area of the etch pits and/or standard etch pits is calculated by using an etch pit image pixel integration method, preferably, when the etch pits and/or standard etch pits are regular triangles, the etch pit area is calculated by the side length of the etch pits.
Advantageous effects
1. The invention heats KOH in advance and then heats KOH and sapphire wafers together, thereby preventing KOH heating time with different volumes from influencing corrosion time and ensuring detection precision.
2. The dislocation density is calculated by calculating the corrosion pits through the area, and compared with the prior art that linear triangles are connected into a string or hollow triangles are difficult to count and then screened out for calculation, the dislocation density is calculated by bringing all the areas of the corrosion pits into a calculation range, and the accuracy of the obtained result is higher.
Meanwhile, the dislocation density detected by the invention comprises the internal dislocation density of the sapphire and the dislocation density caused by uneven stress, uneven stress and the like in production and processing.
3. The erosion method is simple to operate, low in equipment cost and capable of being used for rapid detection of sapphire wafers of enterprises.
Drawings
FIG. 1 is a point diagram of a surface to be measured;
FIG. 2 is a diagram of crystal etch pits;
FIG. 3 is a picture of partially etched pits in sapphire crystal from Tiantong silver Xiamen corporation in example 1;
FIG. 4 is a picture of partially etched pits in sapphire crystal from Tiantong silver Xiamen corporation in example 2;
FIG. 5 is a picture of partially etched pits in a sapphire crystal of Aureode in example 3;
FIG. 6 is a photograph of partially etched pits in sapphire crystal from Tiantong silver Xiamen, inc. in example 4.
Detailed Description
The method and application of the present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.
Example 1:
the sample to be tested is sapphire produced by Tiantong Yinxiao company, the sample to be tested is a crystal wafer with the diameter of 200mm multiplied by 1mm, the crystal wafer is put in melted KOH at the temperature of 360 ℃, the crystal wafer is taken out after being corroded for 20min, the crystal wafer is cleaned by hydrochloric acid and purified water after being cooled for 60s, and the average corrosion pit size is calculated to be 2485 mu m 2 The average dislocation density was 197.5 dislocations/cm 2 。
The partially etched pit picture is shown in fig. 3.
Example 2:
the sample to be tested is sapphire produced by Tiantong Yinxiao, the sample phi 200mm x 1mm wafer to be tested is taken from the side surface of a crystal column, is put into molten KOH at 360 ℃, is taken out after being corroded for 15min, is cleaned by hydrochloric acid and purified water after being air-cooled for 60s, and the average corrosion pit size is calculated to be 1582 mu m 2 Average dislocation density of 442.2/cm 2 。
The partially etched pit picture is shown in fig. 4.
Example 3:
the sample to be tested is sapphire produced by Orude company, the sample to be tested is taken, a wafer with the diameter of 20mm multiplied by 1mm is placed in molten KOH at the temperature of 360 ℃, the wafer is taken out after being corroded for 10min, the wafer is cleaned by hydrochloric acid and purified water after being cooled in air for 60s, and the average corrosion pit size is calculated to be 334 mu m 2 The average dislocation density is 3117.1/cm 2 。
The partially etched pit picture is shown in fig. 5.
Example 4:
the sample to be tested is sapphire produced by Tiantong Yinxiao, the sample to be tested is a crystal plate with the diameter of 200mm multiplied by 1mm, the crystal plate is placed in molten KOH at the temperature of 360 ℃, the crystal plate is taken out after being corroded for 25min, the crystal plate is cleaned by hydrochloric acid and purified water after being cooled for 60s, and the average corrosion pit size is calculated to be 3614 mu m 2 The average dislocation density is 197.4/cm 2 。
The partially etched pit picture is shown in fig. 6.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method of detecting c-plane dislocations in sapphire, comprising the steps of:
s1, corroding a sapphire wafer to be detected in molten potassium hydroxide, and observing a corrosion pit on the c surface of the sapphire wafer by using a microscope after cleaning;
s2, selecting N test points on the c surface to shoot corresponding pictures, calculating the total area of the corrosion pits in the N pictures, and calculating the surface dislocation density of the c surface of the sapphire wafer to be tested.
2. The method for detecting c-plane dislocations in sapphire according to claim 1, wherein the step of selecting N test points on the c-plane to take corresponding pictures specifically comprises the steps of: observing the corrosion pits on the c surface of the sapphire wafer by using a metallographic microscope, selecting N test points with the area of A1 on the c surface, and shooting photos of all the test points;
preferably, N is more than or equal to 5, preferably N is more than or equal to 8 and is evenly distributed, for example, 9, 13; preferably, the N test points are uniformly distributed along the center of the c plane, for example, the N test points are uniformly distributed on a circle with the center of the c plane as the center of the circle;
preferably, the area A1 of each test point is 0.005cm 2 -0.05cm 2 Preferably, the area A1 of the test point is 0.01cm 2 -0.04cm 2 More preferably, the area A1 of the test point is 0.02cm 2 -0.03cm 2 ；
Preferably, there is at least one etch pit on each of the test points.
3. The method for detecting c-plane dislocations in sapphire as claimed in claim 1, wherein the step of calculating the total area of etch pits in the N photographs and calculating the c-plane dislocation density of the sapphire wafer to be detected specifically comprises the steps of: calculating the total area A2 of the etch pits in all the test points according to the photos of the test points, selecting N1 etch pits as standard etch pits, calculating the average area A3 of the standard etch pits, and obtaining the surface dislocation density of the c surface of the sapphire sample according to the (A2/A3)/(N x A1);
preferably, N1. Gtoreq.3, preferably N1. Gtoreq.4, for example 5 or 6.
4. The method for detecting c-plane dislocations in sapphire as claimed in claim 3 wherein the standard etch pits have a regular triangular, distorted polygonal with regular edges approximating a regular triangular or a structure with parallel line spacing ordered by triangles, preferably the standard etch pits are solid regular triangular etch pits; the standard etch pits have the structure shown in fig. 2.
5. The method of detecting c-plane dislocations in sapphire according to claim 3 or claim 4, wherein the areas of N1 of said standard etch pits are similar, for example with a deviation of no more than 20%;
more preferably, the standard etch pits have an area that deviates by no more than 15%, and even more preferably, the standard etch pits have an area that does not exceed 10%.
6. The method for detecting c-plane dislocations in sapphire according to any one of claims 1 to 3, wherein in step S1, the etching is carried out under constant temperature conditions, the etching temperature is 330 ℃ to 400 ℃, the etching time is 10 to 30min, preferably, the etching temperature is 350 ℃ to 380 ℃, and the etching time is 15 to 25min, such as 20min.
Preferably, the etching is performed in a crucible, for example, the potassium hydroxide is put into the crucible in advance and heated to be melted, and then the c-plane of the sapphire wafer to be tested is put into the crucible facing the etching solution to be etched, preferably, the etching is performed in a high-temperature apparatus, for example, a muffle furnace or a tube furnace.
7. The method of claim 1, wherein the sapphire wafer to be tested is cooled in air for 30-120s, such as 60s, before being cleaned.
8. The method for detecting c-plane dislocations in sapphire to be detected according to claim 1, wherein the cleaning of the sapphire to be detected comprises sequentially cleaning the sapphire after etching with an acid solution.
Preferably, the acid solution is dilute hydrochloric acid, dilute nitric acid or dilute sulfuric acid, preferably dilute hydrochloric acid, the concentration of the dilute hydrochloric acid is 1% -20%, the dilute hydrochloric acid is configured by adopting concentrated hydrochloric acid and water according to a volume ratio of 1:1-1:5, for example, the concentrated hydrochloric acid and water according to a volume ratio of 1:3.
9. The method for detecting c-plane dislocations in sapphire as claimed in claim 8, further comprising the step of washing the sapphire with a surfactant solution after washing the sapphire with an acid solution in sequence;
preferably, the surfactant is selected from the group comprising cationic, nonionic or amphoteric surfactants or a combination of two or more thereof; preferably selected from the group comprising sodium linear alkylbenzene sulphonate, sodium fatty alcohol polyoxyethylene ether sulphate, ammonium fatty alcohol polyoxyethylene ether sulphate, sodium lauryl sulphate, lauroyl glutamate, nonylphenol polyoxyethylene ether, stearic acid monoglyceride, lignosulphonate, heavy alkylbenzene sulphonate or alkyl sulphonate or a combination of two or more thereof, for example a laundry powder or a laundry liquor;
preferably, the surfactant solution further comprises a step of washing with water or an alcohol solution, such as purified water, deionized water or methanol, after washing, and the washing is selected from washing or ultrasonic washing, such as ultrasonic washing with purified water.
10. The method for detecting c-plane dislocations in sapphire according to claim 1, wherein the areas of the etch pits and/or standard etch pits are calculated using an etch pit image pixel integration method, preferably the etch pit areas are calculated from the side lengths of the etch pits when the etch pits and/or standard etch pits are regular triangles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111146198.0A CN115876774A (en) | 2021-09-28 | 2021-09-28 | Method for detecting surface dislocation density of c-surface of high-purity sapphire wafer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111146198.0A CN115876774A (en) | 2021-09-28 | 2021-09-28 | Method for detecting surface dislocation density of c-surface of high-purity sapphire wafer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115876774A true CN115876774A (en) | 2023-03-31 |
Family
ID=85755751
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111146198.0A Pending CN115876774A (en) | 2021-09-28 | 2021-09-28 | Method for detecting surface dislocation density of c-surface of high-purity sapphire wafer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115876774A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116577340A (en) * | 2023-05-28 | 2023-08-11 | 兰州大学 | Method for distinguishing threading screw dislocation and threading edge dislocation in silicon carbide |
-
2021
- 2021-09-28 CN CN202111146198.0A patent/CN115876774A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116577340A (en) * | 2023-05-28 | 2023-08-11 | 兰州大学 | Method for distinguishing threading screw dislocation and threading edge dislocation in silicon carbide |
| CN116577340B (en) * | 2023-05-28 | 2024-01-05 | 兰州大学 | Method for distinguishing threading screw dislocation and threading edge dislocation in silicon carbide |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Dash | Copper precipitation on dislocations in silicon | |
| Kinoshita et al. | Zirconium diboride (0001) as an electrically conductive lattice-matched substrate for gallium nitride | |
| US9598790B2 (en) | Pellicle frame and process for manufacturing same | |
| CN104900758A (en) | Method for detecting microdefects of quasi monocrystalline silicon sheets | |
| CN115876774A (en) | Method for detecting surface dislocation density of c-surface of high-purity sapphire wafer | |
| Schwuttke | Study of copper precipitation behavior in silicon single crystals | |
| CN103215632A (en) | Method for growing large-size c-orientation sapphire single crystals | |
| Bruni et al. | Will Czochralski growth of sapphire once again prevail? | |
| CN100451632C (en) | Method for testing GaN single-crystal fault kind and density | |
| Augusto et al. | Residual stress and dislocations density in silicon ribbons grown via optical zone melting | |
| Markovskyi et al. | Structural, luminescence and photoconversion properties of Lu3Al5O12: Ce single crystalline film phosphors for WLED application | |
| Wolny et al. | Reduced metal contamination from crucible and coating using a silicon nitride based diffusion barrier for the growth of cast quasi-single crystalline silicon ingots | |
| McClelland et al. | Surface tension and density measurements for indium and uranium using a sessile-drop apparatus with glow discharge cleaning | |
| Kokubo et al. | Nondestructive visualization of threading dislocations in GaN by micro raman mapping | |
| Yonenaga et al. | Dislocation velocity in GeSi alloy | |
| CN114965468B (en) | Method for distinguishing 4H-silicon carbide surface | |
| Kupka et al. | Influence of different nucleation layers on the initial grain structure of multicrystalline silicon ingots | |
| Kim et al. | Electron backscatter diffraction characterization of microstructure evolution of electroplated copper film | |
| Chen et al. | Defect-related energy structures of AlN nanotips probed by photoluminescence | |
| CN104790032A (en) | Method for laser pulse sputtering deposition preparation of polycrystalline silicon thin film | |
| Guo et al. | Nondestructive nanofabrication on monocrystalline silicon via site-controlled formation and removal of oxide mask | |
| Togashi et al. | Thermal and chemical stabilities of group-III sesquioxides in a flow of either N2 or H2 | |
| CN102503381A (en) | Al2O3 (aluminum oxide) transparent ceramic as substrate material of GaN (gallium nitride)-based LED and preparation method for same | |
| Ding et al. | Comparison study of GaN films grown on porous and planar GaN templates | |
| Hu et al. | Removal of surface residual stress in a sapphire substrate by etching |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |