CN113295616A - Comprehensive test method for SiC wafer and epitaxial layer structure thereof - Google Patents
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- 238000010998 test method Methods 0.000 title claims abstract description 18
- 230000007547 defect Effects 0.000 claims abstract description 52
- 238000003384 imaging method Methods 0.000 claims abstract description 35
- 238000000034 method Methods 0.000 claims abstract description 15
- 238000010226 confocal imaging Methods 0.000 claims abstract description 11
- 230000003746 surface roughness Effects 0.000 claims abstract description 10
- 238000004458 analytical method Methods 0.000 claims abstract description 9
- 230000003287 optical effect Effects 0.000 claims abstract description 9
- 230000005540 biological transmission Effects 0.000 claims abstract description 7
- 230000010287 polarization Effects 0.000 claims abstract description 7
- 238000012512 characterization method Methods 0.000 claims abstract description 5
- 235000012431 wafers Nutrition 0.000 claims description 72
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 58
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 57
- 238000012360 testing method Methods 0.000 claims description 14
- 239000000758 substrate Substances 0.000 claims description 13
- 238000005530 etching Methods 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 5
- 238000012921 fluorescence analysis Methods 0.000 claims description 4
- 238000001917 fluorescence detection Methods 0.000 claims description 3
- 230000003595 spectral effect Effects 0.000 claims description 3
- 238000000799 fluorescence microscopy Methods 0.000 claims description 2
- 239000013078 crystal Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 7
- 238000012876 topography Methods 0.000 description 7
- 239000004065 semiconductor Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000007517 polishing process Methods 0.000 description 3
- 229910002704 AlGaN Inorganic materials 0.000 description 2
- 102000029749 Microtubule Human genes 0.000 description 2
- 108091022875 Microtubule Proteins 0.000 description 2
- 238000005388 cross polarization Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 210000004688 microtubule Anatomy 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 238000001069 Raman spectroscopy Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 230000005516 deep trap Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004943 liquid phase epitaxy Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002488 metal-organic chemical vapour deposition Methods 0.000 description 1
- 238000001451 molecular beam epitaxy Methods 0.000 description 1
- 238000000399 optical microscopy Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000013441 quality evaluation Methods 0.000 description 1
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/9501—Semiconductor wafers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
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Abstract
The invention provides a comprehensive test method for a SiC wafer and an epitaxial layer structure thereof. By adopting the laser confocal imaging system, the microtube defects of the SiC can be observed in a transmission orthogonal polarization mode, the surface appearance of a sample can be observed through differential interference, and the spatial resolution is higher than that of a common optical lens and is as high as 120 nm. Meanwhile, the surface high-resolution three-dimensional morphology imaging can be realized by slicing and scanning in the height direction, so that the surface roughness and other height information can be obtained; it is also possible to distinguish the crystalline quality and uniformity of the epitaxial layer by fluorescence observation, and to obtain information on the distribution of defects and the distribution of polytype structures. Therefore, various characterization and analysis means are integrated, the analysis process is simplified, the working efficiency is improved, and the cost is reduced.
Description
Technical Field
The invention belongs to a comprehensive test method for SiC wafers and epitaxial layer surfaces and subsurface structures thereof, in particular to a comprehensive test method for SiC wafers and epitaxial layer structures thereof for comprehensively analyzing surface roughness and defects.
Background
The SiC material has received wide attention due to its excellent semiconductor characteristics, has a great potential as a base material in the field of electronic devices, and is widely used in high temperature, high frequency, high power, and the like.
However, the lattice defects of the semiconductor substrate or the epitaxial layer on the semiconductor substrate affect the characteristics of the electronic device such as the semiconductor device, and therefore the type and density of the defects are extremely important parameters in terms of substrate quality evaluation.
Different methods are required for analyzing the surface roughness, micropipe defects, thickness of the SiC wafer, and defects in the epitaxial layer, polytype structures. For example, the surface roughness of the SiC wafer needs to be tested by an atomic force microscope, and the test time is long, the test area is small, and the contact test may cause some damage to the surface of the sample. The defects, the thickness, the defects in the epitaxial layer and the representation of the multi-type structure respectively need to use various different testing means such as microscopes, Raman spectrometers and the like, so that the resolution is low, the working efficiency is low, switching among various devices is needed, and testers need to master the operation of different testing devices.
Disclosure of Invention
The invention aims to solve the defects that different devices and test methods are needed to be used for detecting the SiC wafer and the epitaxial layer structure thereof in the prior art, and provides a comprehensive test method for the SiC wafer and the epitaxial layer structure thereof, which integrates various characterization analysis means, simplifies the analysis process, and can correspond the defect appearance and the photoelectric property in a sample one by carrying out two-dimensional scanning, 3D imaging and fluorescence analysis on various defects, thereby improving the working efficiency and reducing the cost.
In order to achieve the purpose, the invention adopts the following technical scheme:
a comprehensive test method for SiC wafers and epitaxial layer structures thereof comprises the steps of detecting the surface roughness of the SiC wafers, the defects and thickness of micropipes and the analysis and characterization of defects and multi-type structures in the epitaxial layers by combining an optical microscope imaging mode, a fluorescence imaging mode and a laser confocal imaging mode.
As a preferable scheme of the invention, the method comprises the following steps:
1) pretreating a silicon carbide wafer sample, and selecting a light source with the wavelength of 405nm to perform side-cut scanning on the silicon carbide wafer sample after pretreatment to obtain the three-dimensional morphology and the roughness of the surface of the sample; in the whole process of cutting, grinding and polishing the wafer, three-dimensional imaging is carried out on the surface of the sample, so that the change of the surface of the sample can be reflected, and the change can also be fed back to the cutting, grinding and polishing process;
2) carrying out two-dimensional scanning on the surface of a silicon carbide wafer sample in a laser confocal imaging mode, and detecting and counting the defects of the micropipes; the surface of the sample is scanned in two dimensions, and the defects of the microtubes can be visually observed in the imaging mode. Because a larger stress field exists near the micro-tube defect, characteristic points similar to butterfly shapes can be observed through a polarization mode, and the characteristic points are the micro-tube defect;
3) detecting and counting scratches, bulges and particles on the surface of the silicon carbide wafer sample through a bright-dark field or differential interference mode; and inserting a differential interference module, namely DIC, switching a common upright metallographic microscope to a DIC imaging mode, comparing, and selecting an objective lens of 10 times to obtain an optimal surface topography image. By the DIC mode, scratches, bumps, particles, and the like on the wafer surface can be observed;
4) etching a silicon carbide wafer sample, comparing and classifying the size, depth and shape of an etching pit through a DIC imaging mode and a laser confocal 3D imaging mode, and distinguishing the types and distribution densities of different defects in the wafer; the etch rate is different due to the different stress levels around the different defects. Therefore, the sizes, depths and shapes of the etching pits can be comparatively classified through the DIC imaging mode and the laser confocal 3D imaging mode, and the types and distribution densities of different defects in the wafer can be distinguished;
5) detecting the thicknesses of the substrate and the epitaxial layer wafer by a laser confocal 3D imaging mode; and switching to a laser confocal 3D imaging mode, and observing the cross sections of the substrate and the epitaxial layer wafer grown on the substrate to measure the thickness of the substrate and the epitaxial layer wafer. The thickness of the substrate and epitaxial layers is also one of the commonly used parameters;
6) performing fluorescence detection on the surface of the silicon carbide wafer sample and the epitaxial layer in a laser confocal 3D imaging mode;
7) by performing the slicing scanning on the epitaxial layer according to the difference of the fluorescence wavelength, and analyzing the result of each slicing scanning, the distribution of the defects or the polytypes in the height direction can be observed. Meanwhile, through the difference of fluorescence wavelengths, not only can the samples be distinguished to contain a plurality of crystal forms, but also the samples can be judged to approximately contain a plurality of energy levels caused by defects, and the relative content of the defects can be confirmed through the fluorescence intensity;
8) and carrying out two-dimensional scanning, 3D imaging and fluorescence analysis on the same position on the surface of the sample, and detecting and counting the corresponding relation between the defect appearance and the photoelectric property in the sample.
As a preferred scheme of the invention, the pretreatment of the silicon carbide wafer sample in the step 1) is to cut, grind and polish the silicon carbide wafer sample to meet the requirement of a mirror surface, and clean the silicon carbide wafer sample for later use; the objective lens is 50 times.
As a preferable scheme of the invention, the thickness of the silicon carbide wafer after sample pretreatment is 300-500 μm.
As a preferred scheme of the invention, in the step 2), the transmission orthogonal polarization mode selects an upright metallographic microscope white light source, the objective lens is 20 times, and the polarizer and the analyzer are inserted.
In a preferred embodiment of the present invention, in step 3), the objective lens is 10 times.
In a preferred embodiment of the present invention, in step 4), the etching is performed by immersing the silicon carbide wafer sample in molten KOH.
As a preferable scheme of the invention, in the step 6), a laser light source with the wavelength of 405nm is selected as the light source, and the spectral resolution is 1 nm.
In a preferred embodiment of the present invention, in step 7), each layer is separated by 290nm in the layer scan.
As a preferable scheme of the invention, in the step 7), the wavelength ranges of the emitted fluorescence are 450nm-500nm, 535nm-600nm and 639nm-700nm respectively.
The invention adopts a laser confocal imaging system, can realize multiple imaging modes of a common optical lens, and comprises the following steps: transflective, bright field, dark field, partial correlation, differential interference, etc. Therefore, a common transmission orthogonal polarization imaging mode can be realized through a laser confocal imaging system, and the defects of the surface microtubes are distinguished and counted. Meanwhile, scratches, particles and the like on the surface of the sample are imaged through a bright and dark field or a differential interference mode. And the imaging of the three-dimensional topography of the surface with a large visual field can be realized, and the resolution in a plane can reach 120 nm.
The laser confocal imaging system is an optical microscopy technology which utilizes a space pinhole to filter out non-focal plane light so as to improve image contrast and obtain the three-dimensional appearance of a sample.
The imaging principle is roughly as follows: the information received by the ordinary optical mirror comes from the focal plane and the non-focal plane. The confocal imaging technology only receives the information of a focal plane, then performs point-to-line laser at a certain Z position, and the line-to-surface scanning is performed to obtain a light slice. And moving the objective table in the Z direction to perform Z-direction layer cutting and scanning on the sample to obtain a specific layer thickness light slice set. In the Z-axis scanning range, the maximum light intensity value is found for each pixel, and the height of the pixel point is positioned, so that the surface three-dimensional morphology is reconstructed.
Compared with the prior art, the invention has the following beneficial effects:
1) the invention solves the problems of low working efficiency and switching on various devices during testing;
2) the invention realizes the analysis and characterization of the surface roughness, the micro-tube defects, the thickness of the SiC wafer and the defects and the multi-type structures in the epitaxial layer on the same equipment, thereby greatly improving the working efficiency;
3) the characteristics of various parameters and structures are realized on the same equipment, so that the working efficiency is improved, the cost investment is reduced, and the economic benefit is improved for enterprises.
Drawings
FIG. 1 is a schematic diagram of a confocal laser imaging system and a structural diagram of the device;
FIG. 2 is a schematic diagram of a laser confocal imaging system for measuring surface roughness;
FIG. 3 is a representation of a micropipe defect using a transmission cross-polarization mode;
FIG. 4 is a representation of the epitaxial layer surface by differential interference and slice scanning, respectively;
FIG. 5 is a series of slice scans of the surface of the epitaxial layer by the confocal laser scanning;
FIG. 6 shows fluorescence analysis of one of the series of layers of FIG. 5.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Interpretation of terms:
i. micropipe defects: a crystal defect in the SiC wafer belongs to the category of linear defects, a physical hole with a diameter of micron order and a penetrating screw dislocation with a larger Burgers vector. The SiC crystal is a specific defect, can extend for a long distance in the crystal and even penetrate through the whole crystal, and has great influence on the performance and the yield of SiC devices.
An epitaxial layer: a thin layer of single crystal of SiC or AlN, GaN, or the like, which is epitaxially grown on a SiC wafer, called an epitaxial layer, is mainly obtained by a chemical vapor deposition technique, a liquid phase epitaxy technique, a molecular beam epitaxy technique, and the like.
The equipment used by the invention mainly adopts a Zeiss laser confocal microscope with the model of LSM 900. The composition mainly comprises: a main body is a Zeiss Axio imager.M2 positive metallographic microscope, a special laser confocal objective lens EC Plan-NEOFLUAR, a light source is a diode laser with 405nm, a detector is a double-channel gallium arsenide phosphide (GaAsP) PMT, the simultaneous spectrum detection is that more than 8 sequence confocal fluorescent channels and at most three parallel confocal fluorescent channels are based on low-noise GaAsP; adjustable in 1nm steps and with variable size pinholes suitable for short wavelength (e.g., 405nm) laser imaging, the primary function is to block out light from non-focal planes.
The invention provides a comprehensive test method of a SiC wafer and an epitaxial layer structure thereof, which comprises the following steps:
1) the SiC wafer is cut, ground and polished to be approximately 300-500 mu m in thickness, the wafer is placed on a sample table, a light source with the laser wavelength of 405nm is selected, the objective lens is 50 times, the surface of the sample is automatically subjected to side cutting scanning, and the three-dimensional shape and the roughness of the surface of the sample can be obtained. In the whole process of cutting, grinding and polishing the wafer, the surface of the sample is subjected to three-dimensional imaging, so that the change of the surface of the sample can be reflected, and the change can also be fed back to the cutting, grinding and polishing process.
2) Then, the mode is switched to a transmission orthogonal polarization mode of laser confocal, a common upright metallographic microscope white light source is selected, an objective lens is 20 times, and a polarizer and an analyzer are inserted. The surface of the sample is scanned in two dimensions, and the defects of the microtubes can be visually observed in the imaging mode. Because of the larger stress field near the microtubule defect, a characteristic point similar to a butterfly shape can be observed through a polarization mode, and the characteristic point is the microtubule defect.
3) And inserting a differential interference module, namely DIC, switching a common upright metallographic microscope to a DIC imaging mode, comparing, and selecting an objective lens of 10 times to obtain an optimal surface topography image. By the DIC mode, scratches, protrusions, particles, and the like on the wafer surface can be observed.
4) In order to investigate the various types of structural defects present in the wafer, the wafer was immersed in molten KOH for etching. The etch rate is different due to the different stress levels around the different defects. Therefore, the sizes, depths and shapes of the etching pits can be comparatively classified through the DIC imaging mode and the confocal laser 3D imaging mode, and the types and distribution densities of different defects in the wafer can be distinguished.
5) And switching to a laser confocal 3D imaging mode, and observing the cross sections of the substrate and the epitaxial layer wafer grown on the substrate to measure the thickness of the substrate and the epitaxial layer wafer. The thickness of the substrate and the epitaxial layer is also one of the commonly used parameters.
6) The epitaxial layer grown in this experiment is an AlN material, but is not limited to the AlN material. The method is characterized in that a laser confocal 3D imaging mode is used, a 405nm laser light source is selected, the spectral resolution is 1nm, fluorescence detection is carried out on the surface of a wafer and an epitaxial layer, the technical reason is limited at present, and the shortest wavelength in the equipment is only the 405nm laser light source, so that only a part of deep level defects in the wafer and the epitaxial layer can be observed. If the laser light source with the wavelength less than 380nm exists, the crystal quality, defect distribution and polytype distribution in the wafer and the epitaxial layer can be researched.
7) By analyzing the results of each slice scan, the distribution of defects, polytypes, or the like in the height direction can be observed. Meanwhile, through the difference of fluorescence wavelengths, not only can the samples be distinguished to contain a plurality of crystal forms, but also the samples can be judged to approximately contain a plurality of energy levels caused by defects, and the relative content of the defects can be confirmed through the fluorescence intensity.
Fig. 1 is a schematic diagram of a confocal laser scanning imaging technique, which is similar to the optical path of a conventional optical microscope and also integrates a conventional metallographic microscope, filters out signals from a non-focal plane through a spatial pinhole, receives signals from a focal plane by means of slicing scanning within a certain height range, and reconstructs the three-dimensional topography of the surface, as shown in fig. 2.
Since a high-resolution surface three-dimensional topography can be obtained, the surface roughness can also be obtained, which is one of the more important values in the wafer geometry. And meanwhile, the maximum peak height and the maximum depression height of the surface can be obtained. The roughness and other parameters of both front and back surfaces of the high purity 4H-SiC wafer were tested in this example as shown in table 1.
TABLE 1 measurement of roughness and maximum waviness of both front and back surfaces of SiC wafer surface
Different expression methods of surface roughness, the maximum height of the surface and the maximum depression height can be obtained from the test results, and the difference of the geometric shapes on the two surfaces of the wafer can be directly compared, so that the grinding and polishing process of the wafer can be better fed back. Meanwhile, various height tests of the surface are also certified by ISO, and the test method can be used as a common test means. And because the test is contactless, so have to have the surface of the sample not damaged, test the wide range, characteristics such as the test time is short.
In addition, micropipe defects in SiC are usually observed with a transmission cross polarization microscope in an optical microscope, as shown in fig. 3. The result is obtained in a laser confocal imaging system, and the surface high-resolution three-dimensional morphology can be realized, and the three-dimensional morphology and the three-dimensional morphology and the two-dimensional and the three-dimensional morphology and the three-dimensional and the.
In addition, by using the confocal laser imaging system, the microscopic relief (10 times of objective lens) of the surface can be obtained by using a differential interference mode, as shown in fig. 4(a), and the three-dimensional topography (20 times of objective lens) of the surface can also be obtained, as shown in fig. 4 (b). In this example, the AlGaN epitaxial layer is obtained by MOCVD on the SiC surface, because the growth process is not mature, various undulations on the epitaxial layer surface can be observed, especially, several protrusions are parallel to each other on the surface, and through the three-dimensional morphology, whether the protrusions or the pits can be visually distinguished, and the heights of the protrusions can also be estimated.
The epitaxial layers were layer-sliced 290nm apart to observe the surface topography in each layer, as shown in fig. 5. The laser confocal layer-by-layer scanning plane is highlighted, and the characteristics of high spatial resolution compared with a common optical microscope are highlighted.
In addition, a laser light source with 405nm is used, fluorescence observation is carried out on any region (shown in fig. 6 (a)) of the epitaxial layer in a laser confocal system, fluorescence can be observed in the wavelength ranges of 450nm-500nm (shown in fig. 6 (b)), 535nm-600nm (shown in fig. 6 (c)) and 639nm-700nm (shown in fig. 6(d)), and the region emitting the fluorescence has a certain corresponding relation with the real space morphology. Therefore, the defects possibly existing in the epitaxial layer material can be preliminarily judged and known, and the epitaxial layer material can be further characterized by other analysis means.
The distribution of defects on the surface of the epitaxial layer, the positions of defect levels approximately in the forbidden band, and the like can be known through fluorescence observation. Due to the large forbidden band width of the third generation semiconductor materials represented by SiC, more comprehensive information such as the uniformity of AlGaN epitaxial layers and the distribution analysis of SiC polytype structures such as 4H,6H, etc. crystal type distribution in SiC homoepitaxial layers can be obtained if a sample (e.g., 325nm) is de-excited using laser light of a shorter wavelength.
While the invention has been described with respect to a preferred embodiment, it will be understood by those skilled in the art that the foregoing and other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention. Those skilled in the art can make various changes, modifications and equivalent arrangements, which are equivalent to the embodiments of the present invention, without departing from the spirit and scope of the present invention, and which may be made by utilizing the techniques disclosed above; meanwhile, any changes, modifications and variations of the above-described embodiments, which are equivalent to those of the technical spirit of the present invention, are within the scope of the technical solution of the present invention.
Claims (10)
1. A comprehensive test method for SiC wafers and epitaxial layer structures thereof is characterized by comprising the steps of detecting the surface roughness of the SiC wafers, the defects and thickness of micropipes and the analysis and characterization of defects and multi-type structures in the epitaxial layers by combining an optical microscope imaging mode, a fluorescence imaging mode and a laser confocal imaging mode.
2. The integrated test method for the SiC wafer and the epitaxial layer structure thereof according to claim 1, characterized by comprising the following steps:
1) pretreating a silicon carbide wafer sample, and selecting a light source with the wavelength of 405nm to perform side-cut scanning on the silicon carbide wafer sample after pretreatment to obtain the three-dimensional morphology and the roughness of the surface of the sample;
2) carrying out two-dimensional scanning on the surface of a silicon carbide wafer sample in a laser confocal imaging mode, and detecting and counting the defects of the micropipes;
3) detecting and counting scratches, bulges and particles on the surface of the silicon carbide wafer sample through a bright-dark field or differential interference mode;
4) etching a silicon carbide wafer sample, comparing and classifying the size, depth and shape of an etching pit through a DIC imaging mode and a laser confocal 3D imaging mode, and distinguishing the types and distribution densities of different defects in the wafer;
5) detecting the thicknesses of the substrate and the epitaxial layer wafer by a laser confocal 3D imaging mode;
6) performing fluorescence detection on the surface of the silicon carbide wafer sample and the epitaxial layer in a laser confocal 3D imaging mode;
7) the epitaxial layer is subjected to slicing scanning through the difference of the fluorescence wavelengths, and the distribution of defects or polytypes in the height direction can be observed by analyzing the result of each slice of slicing scanning;
8) and carrying out two-dimensional scanning, 3D imaging and fluorescence analysis on the same position on the surface of the sample, and detecting and counting the corresponding relation between the defect appearance and the photoelectric property in the sample.
3. The integrated test method of the SiC wafer and the epitaxial layer structure thereof according to claim 2, wherein the pretreatment of the silicon carbide wafer sample in the step 1) is to cut, grind and polish the silicon carbide wafer sample to meet the requirement of a mirror surface, and to clean the silicon carbide wafer sample for later use; the objective lens is 50 times.
4. The integrated test method of SiC wafer and its epitaxial layer structure as defined in claim 3, wherein the thickness of the pretreated SiC wafer is 300-500 μm.
5. The integrated test method of the SiC wafer and the epitaxial layer structure thereof according to claim 2, wherein in the step 2), the transmission orthogonal polarization mode adopts an upright metallographic microscope white light source, the objective lens is 20 times, and the polarizer and the analyzer are inserted.
6. The method for comprehensively testing the structures of the SiC wafer and the epitaxial layers thereof according to claim 2, wherein in the step 3), the objective lens is 10 times.
7. The integrated test method for the SiC wafer and the epitaxial layer structure thereof according to claim 2, wherein in the step 4), the etching is to immerse the silicon carbide wafer sample into molten KOH.
8. The method for comprehensively testing the SiC wafer and the epitaxial layer structure thereof according to claim 2, wherein in the step 6), a laser source with the spectral resolution of 1nm is selected as the light source and used as the light source of 405 nm.
9. The integrated test method for the SiC wafer and the epitaxial layer structure thereof according to claim 2, wherein in the step 7), each layer is separated by 290nm in the layer scanning.
10. The integrated test method for the SiC wafer and the epitaxial layer structure thereof according to claim 2, wherein in the step 7), the wavelength ranges of the emitted fluorescence are 450nm to 500nm, 535nm to 600nm and 639nm to 700nm respectively.
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| CN114280009A (en) * | 2021-12-31 | 2022-04-05 | 北京天科合达半导体股份有限公司 | Comprehensive defect detection device and method for silicon carbide wafer |
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| CN114527143A (en) * | 2022-04-22 | 2022-05-24 | 浙江大学杭州国际科创中心 | Nondestructive testing semiconductor defect evolution method, system and device |
| CN116130377A (en) * | 2023-04-17 | 2023-05-16 | 西安奕斯伟材料科技股份有限公司 | Method, device and system for detecting defects of epitaxial wafer and manufacturing method thereof |
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