A system and method for nanoscale depth-resolved analysis of electrode surfaces

Abstract

The application belongs to the technical field of material surface analysis, and discloses a pole surface nanoscale depth resolution analysis system and method. The application filters out deep-layer scattered electrons and air stray interference of a material, and only retains effective resonance Auger electron signals of a pole surface layer. The application uses the extremely shallow escape characteristic of resonance Auger electrons, combines a directional collimation gating assembly to perform structure depth limiting, cooperates with high-precision angle-variable sample table high-precision angle-variable regulation and control and an electron escape depth formula to perform depth conversion, realizes continuous atomic layer gradient scanning in the range of the pole surface layer, and avoids problems of angle deviation, depth drift and signal distortion by real-time correction of sample posture deviation, so as to ensure the detection depth accuracy and signal stability in the scanning process. The application has high anti-interference capability and high signal-to-noise ratio detection advantages, can identify weak characteristic signals such as sub-nanometer defects, low-concentration doping and single-atom adsorption, improves the reliability of weak signal detection of a pole surface, and realizes depth resolution detection of the pole surface.

Description

Technical Field

[0001] This invention relates to the field of material surface analysis technology, specifically to an extreme surface nanoscale depth resolution analysis system and method. Background Technology

[0002] The polar surface of a material refers to the structure and chemical state of the outermost 1-2 nm atomic layer. It is the only interface through which the material exchanges matter, transfers energy, and transfers charge with the outside world. In fields such as catalysis, corrosion, energy, semiconductors, two-dimensional materials, and biological interfaces, key reactions, active sites, interfacial electron transfer, atomic diffusion, and defect evolution all occur within the 1-2 nm range of the polar surface. The atomic arrangement, elemental distribution, electronic structure, chemical valence state, and defect type of the polar surface directly determine whether the material has core properties such as high catalytic activity, high corrosion resistance, high interfacial stability, and high carrier mobility.

[0003] Achieving atomic-level depth resolution, simultaneous analysis of electronic structure and chemical state, and high-sensitivity detection of weak signals on 1-2nm polar surfaces is a key prerequisite for modern materials science to break through the bottleneck of mechanism understanding and achieve precise materials design. Existing mainstream surface analysis techniques, such as AR-XPS variable-angle X-ray photoelectron spectroscopy, methods for distinguishing depths by different yields, and methods for distinguishing depths by different electron yields, all have certain shortcomings.

[0004] Variable-angle X-ray photoelectron spectroscopy (XPS) achieves depth detection by exciting surface photoelectrons with X-rays and utilizing the characteristic that photoelectron scattering varies with the exit angle. By changing the sample angle, the exit angle of the photoelectrons is altered. The flatter the exit angle (grazing angle), the shorter the path of the photoelectrons in the material, indicating they can only escape from a more superficial layer. Conversely, the more perpendicular the exit angle, the longer the path, indicating they originate from a deeper layer. This allows for detection at different depths. Under conventional conditions, depth resolution of 3–5 nm can be achieved, obtaining elemental composition and chemical valence state information at different depths. However, due to limitations in photoelectron scattering characteristics, it is difficult to stably reach the 1–2 nm extreme surface layer. Furthermore, in oxides and semiconductors, extreme surface layer signals are easily masked by deeper layer signals, providing only static chemical valence state information. This fails to reflect dynamic electronic structure processes such as electronic excitation, transitions, and de-excitation. The detection sensitivity and signal-to-noise ratio for weak signals such as sub-nanometer defects, single-atom adsorption, and low-concentration doping are insufficient, making reliable identification difficult.

[0005] The method of differentiating depths by different yields utilizes the significant difference in penetration ability between the fluorescence signal and the electron signal generated after synchrotron radiation excitation to achieve depth resolution. Although fluorescence photons have extremely strong penetrating ability and can detect depths of hundreds of nanometers, mainly reflecting bulk phase information of materials, the electrons generated by excitation have weak penetrating ability and can detect depths of only tens of nanometers, which can only reflect shallow surface information. By comparing the ratio of fluorescence yield to electron yield, the difference between surface and bulk phase composition can be indirectly reflected. However, this method is only suitable for a rough distinction between tens of nanometers of surface layer and hundreds of nanometers of bulk phase, and cannot penetrate 1-2 nm of the extreme surface layer. Moreover, the obtained signal is a large-scale average signal, which cannot reflect fine changes at the atomic layer scale. The resolution and sensitivity cannot meet the requirements of precise characterization of extreme surface information in catalysis, corrosion, and other processes.

[0006] The method of distinguishing depth by different electron yields achieves relative depth resolution by collecting two types of signals: total electron yield and partial electron yield. Total electron yield collects all emitted electrons, with a detection depth of about 10-20 nm, reflecting the average information of a thicker surface layer. Partial electron yield only collects electrons emitted at specific energies or angles, with a detection depth of about 3-5 nm, corresponding to a shallower surface region. By comparing the signal intensities of the two, a certain range of depth distinction can be achieved. The conventional resolution capability is between 5-10 nm. Due to the limitations of electron energy distribution and scattering characteristics, it cannot stably reach the 1-2 nm polar surface layer. Moreover, the signal is still an average result within a certain thickness, making it difficult to distinguish the differences of single atomic layers. It also cannot simultaneously obtain the synergistic information of electronic structure and chemical state, and cannot support the systematic study of the atomic-level evolution law of the polar surface.

[0007] Therefore, existing technologies are all unable to achieve stable coverage of 1-2nm extreme surfaces, atomic-level depth gradient resolution, simultaneous analysis of electronic structure and chemical state, and high-sensitivity detection of sub-nanometer weak signals, and cannot meet the technical requirements of fields such as catalytic mechanism analysis, corrosion mechanism research, two-dimensional material interface regulation, and energy material surface optimization.

[0008] In view of this, this application provides a nanoscale depth-resolution analysis system and method for polar surfaces. Summary of the Invention

[0009] The purpose of this invention is to provide a nanoscale depth-resolution analysis system and method for polar surfaces, which is suitable for the synergistic characterization of atomic-level electronic structure and chemical state of metals, oxides, semiconductors, two-dimensional materials, etc.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A polar surface nanoscale depth-resolution analysis system includes: a synchrotron radiation photon modulation component, a high-precision variable angle sample stage, a sample surface normal self-alignment mechanism, a directional collimation gating component, an electron energy analyzer, and an ultra-high vacuum environment chamber;

[0012] The ultra-high vacuum environment cavity is used to provide and maintain an ultra-high vacuum working environment;

[0013] The synchrotron radiation photonic modulation component is used to receive a broadband beam of synchrotron radiation, and after monochromatization, slit modulation and superfocusing, output a soft X-ray beam with continuously adjustable energy, monochromaticity and stable brightness.

[0014] The high-precision variable-angle sample stage is set in an ultra-high vacuum chamber to stably support the sample to be tested and to adjust the spatial position and angular orientation of the sample to be tested.

[0015] The sample surface normal self-alignment mechanism is integrated into the high-precision variable angle sample stage. It is used to detect and correct the attitude of the high-precision variable angle sample stage in real time during the angle adjustment process of the high-precision variable angle sample stage, and control the spatial orientation of the sample surface normal to the receiving center of the orientation collimation selection component.

[0016] The directional collimation and gating component is coaxially arranged between the high-precision variable-angle sample stage and the electron energy analyzer. It is used to filter out large-angle scattered electrons and deep stray electron signals, suppress deep signal interference, and only allow resonant Auger electrons emitted at small angles near the sample surface normal to pass through.

[0017] The electron energy analyzer is located at the rear end of the directional collimation gating component. It is used to receive the screened resonant Auger electrons, perform high-precision resolution and signal acquisition of the electron energy, identify the electronic energy level structure, orbital hybridization characteristics and defect electronic state information corresponding to Auger electrons of different energies, and form a deep-resolution resonant Auger electron spectrum.

[0018] Preferably, the synchrotron photonic modulation component includes:

[0019] A grating monochromator is used to disperse and separate a broadband beam of synchrotron radiation according to photon energy, thereby selecting a monochromatic beam with a single energy.

[0020] Slit elements are used to spatially confine and intensity-regulate monochromatic beams, eliminating stray light and higher-order diffraction light from the edges, and obtaining collimated beams with regular cross-sections, small divergence angles, and higher energy purity.

[0021] Focusing optical elements are used to converge a collimated beam into a focused spot, forming a soft X-ray beam with continuously adjustable energy, monochromaticity, and stable brightness.

[0022] Preferably, the sample surface normal self-alignment mechanism includes:

[0023] The dual laser reflection alignment unit is used to receive the detection beam reflected from the sample surface and to identify the normal direction of the sample surface in real time through the laser reflection of the detection beam.

[0024] A four-quadrant detector is used to capture the positional deviation of the reflected spot of the detection beam;

[0025] A closed-loop fine-tuning radio is used to output a control signal based on the position deviation of the reflected light spot detected by the four-quadrant detector, drive the high-precision variable-angle sample stage to adjust its attitude, and control the spatial orientation of the sample surface normal to the receiving center of the directional collimation gating component.

[0026] Preferably, the high-precision variable-angle sample stage includes:

[0027] A rotary drive element is used to drive the sample to rotate continuously within a set angle range, so as to change the angle between the sample surface and the incident soft X-ray beam and synchronously control the emission angle of resonant Auger electrons.

[0028] An attitude adjustment element is used to adjust the spatial orientation of the sample surface normal according to the control signal output by the closed-loop fine-tuning radio.

[0029] Preferably, the directional collimation and gating component includes:

[0030] The multi-level adjustable aperture aperture is a group of multiple coaxially arranged micro-aperture apertures with progressively converging apertures, used to progressively screen, match and output a resonant Auger electron beam with uniform flux and appropriate density.

[0031] Angle-limiting collimating cylinder is a hollow cylindrical structure with a fixed inner diameter and axial length. It is used to limit the electron receiving solid angle, allowing only resonant Auger electrons emitted at a small angle near the normal to the sample surface to pass through.

[0032] The background suppression baffle is a ring-shaped light-shielding baffle structure used to block residual scattered electrons and large-angle diffuse reflection electrons in the outer region of the directional collimation gating component.

[0033] Preferably, the ultra-high vacuum environment cavity comprises:

[0034] Vacuum chambers are used to provide ultra-high vacuum working spaces;

[0035] A vacuum valve is used to achieve graded sealing and gas path switching within the vacuum chamber;

[0036] A vacuum gauge is used to monitor the vacuum level inside the vacuum chamber in real time.

[0037] The vacuum pump unit is used to continuously remove residual gas from the vacuum chamber and maintain the ultra-high vacuum working environment within the vacuum chamber.

[0038] This invention also discloses a method for nanoscale depth-resolution analysis of polar surfaces, comprising the following steps:

[0039] S1. Sample pretreatment and vacuum loading: The sample to be tested is cleaned to remove surface oil, dust and adsorbed impurities. The pretreated sample is fixed on a high-precision variable angle sample stage. The ultra-high vacuum environment cavity provides and maintains a working environment with a preset ultra-high vacuum degree. After standing and stabilizing, the sample pretreatment is completed.

[0040] S2. Automatic alignment and calibration of sample normals: The sample surface normal self-alignment mechanism is activated to detect and correct the attitude of the high-precision variable angle sample stage, and to control the spatial orientation of the sample surface normals to the receiving center of the orientation collimation selection component, thus completing the attitude calibration before testing.

[0041] S3. Synchrotron radiation beam modulation and resonant excitation: The synchrotron radiation photonic modulation component receives an external synchrotron radiation broadband beam, which, after monochromaticization, slit modulation and superfocusing, outputs a soft X-ray beam with continuously adjustable energy, monochromaticity and stable brightness. It matches the resonant absorption energy of the element to be measured and performs specific resonant excitation on the 1-2nm polar surface layer of the sample to generate a high-intensity resonant Auger electron signal.

[0042] S4. Variable Angle Gradient Scanning and Depth-Resolved Acquisition: The high-precision variable angle sample stage is continuously rotated within a preset step size in the range of 0-90°. Based on the depth conversion relationship, the Auger electron escape depth is continuously changed. The directional collimation gating component filters out large-angle scattered electrons and deep stray electron signals, suppresses deep signal interference, and only allows resonant Auger electrons emitted at small angles near the sample surface normal to pass through. The electron energy analyzer receives the screened resonant Auger electrons and performs high-precision resolution and signal acquisition on the electron energy. It identifies the electronic energy level structure, orbital hybridization characteristics and defect electronic state information corresponding to Auger electrons of different energies, forming a depth-resolved resonant Auger electron spectrum.

[0043] S5. Data Fusion and Polar Surface Characterization Analysis: Normalize, correct, noise-remove and fit peak shapes of multiple sets of angle-depth-electron energy spectrum data of the acquired resonance Auger electron spectrum to construct 1-2nm atomic-level depth-resolution electronic structure spectrum of the polar surface, analyze the electronic state density, orbital hybridization and defect electronic state evolution law of different atomic layers, and complete the high-precision analysis and characterization of the polar surface.

[0044] Preferably, the step of activating the sample surface normal self-alignment mechanism to detect and correct the attitude of the high-precision variable-angle sample stage includes:

[0045] The dual laser reflection alignment unit receives the detection beam reflected from the sample surface, and the laser reflection of the detection beam identifies the normal direction of the sample surface in real time.

[0046] The four-quadrant detector captures the position deviation of the reflected light spot of the detection beam and feeds back the position deviation of the reflected light spot;

[0047] The closed-loop fine-tuning radio outputs a control signal based on the position deviation of the reflected light spot fed back by the four-quadrant detector, which drives the high-precision variable-angle sample stage to adjust its attitude and control the spatial orientation of the sample surface normal to the receiving center of the orientation collimation gating component.

[0048] Preferably, the receiving of an external synchrotron radiation broadband beam, after monochromaticization, slit modulation, and superfocusing, outputs a soft X-ray beam with continuously adjustable energy, stable monochromaticity, and stable brightness, comprising:

[0049] The grating monochromator disperses the received external synchrotron radiation broadband beam according to photon energy, and filters out monochromatic beams with single energy.

[0050] The slit element spatially confines and intensifies the monochromatic beam, eliminating stray light from the edges and higher-order diffraction light, and obtaining a collimated beam with a regular cross-section, small divergence angle, and higher energy purity.

[0051] Focusing optical elements converge the collimated beam into a focused spot, forming a soft X-ray beam with continuously adjustable energy, monochromaticity, and stable brightness.

[0052] Preferably, the filtering of large-angle scattered electrons and deep-layer stray electron signals, suppressing deep-layer signal interference, and allowing only resonant Auger electrons emitted at small angles near the sample surface normal to pass through includes:

[0053] Through the multi-stage adjustable aperture aperture group with multiple coaxial arrangement and progressively converging apertures, a resonant Auger electron beam with uniform flux and appropriate density is output by step-by-step screening, matching and output.

[0054] Angle-limiting collimating cylinder restricts the electron receiving solid angle, allowing only resonant Auger electrons emitted at small angles near the sample surface normal to pass through;

[0055] Background suppression baffles block residual scattered electrons and large-angle diffuse reflection electrons in the outer region of the directional collimation gating component.

[0056] Beneficial effects

[0057] This invention utilizes the extremely shallow escape characteristics of resonant Auger electrons, combined with a directional collimation gating component for structural depth limiting, and with the high-precision variable angle control of a high-precision variable angle sample stage and the depth conversion using the electron escape depth formula, it can achieve continuous atomic layer gradient scanning within the 1-2nm polar surface range. This overcomes the shortcomings of traditional technologies, such as high lower depth limits and inability to distinguish single atomic layers, and achieves ultra-fine depth resolution detection of the polar surface.

[0058] This invention employs multiple methods, including directional small-angle electron screening, background stray signal suppression, and ultra-high vacuum environment noise reduction, to filter out deep-layer scattered electrons and air stray interference from the material, retaining only the effective resonant Auger electron signal on the electrode surface. It possesses strong anti-interference capabilities and high signal-to-noise ratio detection advantages, and can accurately identify weak characteristic signals such as sub-nanometer defects, low-concentration doping, and single-atom adsorption, significantly improving the reliability of weak signal detection on the electrode surface.

[0059] This invention solves the problems of angle offset, depth drift, and signal distortion in traditional variable angle testing by adding a sample surface normal self-alignment mechanism and real-time closed-loop correction of sample attitude deviation. It ensures accurate detection depth and stable signal during scanning, resulting in excellent system detection stability and repeatability, and provides reliable data support for the study of the evolution law of atomic layers on the polar surface.

[0060] This invention employs an ultra-high vacuum non-destructive testing method, which eliminates the need for etching and damage to the original surface structure of the sample, and completely preserves the true atomic and electronic states of the 1-2nm polar surface layer. This enables non-destructive, in-situ, and highly universal polar surface characterization, and can be widely applied to the characterization of the electronic structure of polar surfaces of various materials such as metals, oxides, semiconductors, and two-dimensional materials. It has extremely high application value in the fields of catalysis, corrosion, energy, and semiconductor interface research. Attached Figure Description

[0061] Figure 1 A schematic diagram of a polar surface nanoscale depth resolution analysis system provided by the present invention;

[0062] Figure 2 A schematic diagram of the structure of an extreme surface nanoscale depth resolution analysis system provided by the present invention;

[0063] Figure 3 A schematic diagram illustrating the steps of a nanoscale depth-resolution analysis method for polar surfaces provided by this invention. Detailed Implementation

[0064] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. The following embodiments are used to illustrate the present invention, but should not be used to limit the scope of protection of the present invention. The conditions in the embodiments can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention are all within the scope of protection claimed by the present invention.

[0065] Example 1

[0066] Please refer to Figures 1-2 This embodiment provides a polar surface nanoscale depth resolution analysis system, including a synchrotron radiation photon modulation component, a high-precision variable angle sample stage, a sample surface normal self-alignment mechanism, a directional collimation gating component, an electron energy analyzer, and an ultra-high vacuum environment chamber;

[0067] Ultra-high vacuum environment chamber, used to provide and maintain an ultra-high vacuum working environment;

[0068] Synchrotron radiation photonic modulation component is used to receive synchrotron radiation broadband beams, and after monochromatization, slit modulation and superfocusing, output soft X-ray beams with continuously adjustable energy, monochromaticity and stable brightness.

[0069] The high-precision variable-angle sample stage is set in an ultra-high vacuum chamber to stably support the sample to be tested and to adjust the spatial position and angular orientation of the sample to be tested.

[0070] The sample surface normal self-alignment mechanism is integrated into the high-precision variable angle sample stage. It is used to detect and correct the attitude of the high-precision variable angle sample stage in real time during the angle adjustment process, and control the spatial orientation of the sample surface normal to the receiving center of the orientation collimation gating component.

[0071] The directional collimation and gating component is coaxially arranged between the high-precision variable-angle sample stage and the electron energy analyzer. It is used to filter out large-angle scattered electrons and deep stray electron signals, suppress deep signal interference, and only allow resonant Auger electrons emitted at small angles near the sample surface normal to pass through.

[0072] The electron energy analyzer is located at the rear end of the directional collimation gating component. It is used to receive the screened resonant Auger electrons, perform high-precision resolution and signal acquisition of electron energy, identify the electronic energy level structure, orbital hybridization characteristics and defect electronic state information corresponding to Auger electrons of different energies, and form a deep-resolution resonant Auger electron spectrum.

[0073] It enables continuous gradient detection and high-purity electronic structure signal acquisition of the 1-2nm polar surface layer, meeting the needs of precise characterization of the evolution of atomic-level electronic structure of the polar surface with depth in fields such as catalysis, corrosion, and two-dimensional materials.

[0074] The ultra-high vacuum environment chamber includes: a vacuum chamber for providing an ultra-high vacuum working space; a vacuum valve for achieving staged sealing and gas path switching within the vacuum chamber; a vacuum gauge for real-time monitoring of the vacuum level within the vacuum chamber; and a vacuum pump unit for continuously removing residual gas from the vacuum chamber to maintain the ultra-high vacuum working environment. The ultra-high vacuum environment chamber maintains a vacuum level of 5 × 10⁻⁶. -10 mBar-1×10 -9 The ultra-high vacuum working atmosphere of mBar avoids the adsorption and contamination of samples by air impurities, eliminates the scattering interference of residual gases on low-energy Auger electrons, and ensures stable and lossless transmission of electron signals on the electrode surface, providing a basic environmental guarantee for high-precision electrode surface depth resolution testing.

[0075] The synchrotron radiation photon modulation assembly includes: a grating monochromator, used to disperse the synchrotron radiation broadband beam according to photon energy and filter out monochromatic beams of single energy; a slit element, used to spatially confine and intensify the monochromatic beam, eliminating stray light and higher-order diffraction light at the edges, and obtaining a collimated beam with a regular cross-section, small divergence angle, and higher energy purity; and a focusing optical element, used to converge the collimated beam into a focused spot to form a soft X-ray beam with continuously adjustable energy, monochromaticity, and stable brightness.

[0076] Specifically, the synchrotron radiation broadband beam comes from the continuous broadband electromagnetic radiation generated by the synchrotron radiation device, covering the vacuum ultraviolet to soft X-ray bands, with an energy range of 100 eV to 1200 eV.

[0077] When a synchrotron radiation broadband beam passes through a grating monochromator, the continuous broadband beam is dispersed according to photon energy based on Bragg's diffraction theorem. A monochromatic beam with a single central energy and extremely narrow energy bandwidth is selected, achieving precise selection and continuous adjustment of photon energy. When the monochromatic beam passes through a slit element, the slit element spatially confines and intensifies the beam, eliminating stray light and higher-order diffracted light from the edges, resulting in a collimated beam with a regular cross-section, small divergence angle, and higher energy purity. When the collimated beam passes through a focusing optics element, it converges into a small, uniformly sized, concentrated, and stable focused spot, forming a soft X-ray beam with continuously adjustable energy, monochromaticity, and stable brightness. This soft X-ray beam can precisely irradiate the test area on the surface of the sample. The energy of the formed soft X-ray beam can be adjusted to monochromatic light from 100 eV to 1200 eV according to usage requirements, and the size of the focused spot is 0.8*0.3 mm. 2 luminous flux greater than 10 10 phs / s.

[0078] The high-precision variable angle sample stage includes: a rotary drive element, used to drive the sample to rotate continuously within a set angle range to change the angle between the sample surface and the incident soft X-ray beam, and synchronously control the emission angle of resonant Auger electrons; and an attitude adjustment element, used to adjust the spatial orientation of the sample surface normal according to the control signal output by the closed-loop fine-tuning radio.

[0079] The high-precision variable-angle sample stage has the ability to continuously rotate from 0 to 90° and adjust the three-dimensional precision displacement. The rotation angle control accuracy is ±0.01°, which can accurately change the angle between the sample surface and the incident soft X-ray beam, and simultaneously control the emission angle of resonant Auger electrons, thereby changing the electron escape path length. It can realize continuous gradient scanning at the atomic level depth within the 1-2nm polar surface range, providing a precise and controllable angle adjustment basis for polar surface depth resolution detection.

[0080] Specifically, the electron escape depth follows the electron escape depth formula:

[0081]

[0082] In the formula, The mean free path of electron inelastic scattering. The emission angle of the resonant Auger electrons, The smaller the angle, The smaller the value, the shallower the electron escape depth, and vice versa.

[0083] Specifically, the high-precision variable angle sample stage was purchased from PREVAC in Poland. The corresponding model on the official website is TransportBoxes, which includes four adjustment axes: X, Y, Z, and R.

[0084] The sample surface normal self-alignment mechanism includes: a dual laser reflection alignment unit, used to receive the detection beam reflected from the sample surface and identify the direction of the sample surface normal in real time through the laser reflection of the detection beam; a four-quadrant detector, used to capture the position deviation of the reflected spot of the detection beam; and a closed-loop fine-tuning radio, used to output a control signal according to the position deviation of the reflected spot detected by the four-quadrant detector, drive the high-precision variable angle sample stage to adjust its attitude, and control the spatial orientation of the sample surface normal to the receiving center of the orientation collimation gating component.

[0085] The dual laser reflection alignment unit receives the detection beam reflected from the sample surface, and the laser reflection of the detection beam identifies the normal direction of the sample surface in real time; the four-quadrant detector captures the position deviation of the reflected spot of the detection beam and feeds back the position deviation of the reflected spot; the closed-loop fine-tuning radio outputs a control signal based on the position deviation of the reflected spot fed back by the four-quadrant detector, drives the high-precision variable angle sample stage to adjust its attitude, and controls the spatial orientation of the sample surface normal to the receiving center of the orientation collimation gating component.

[0086] Specifically, the sample surface normal self-alignment mechanism is basically the same as the laser positioning, spot deviation detection, and closed-loop attitude correction mechanism used in existing laser interferometers, precision optical alignment systems, and beam pointing stabilization systems. It is a common method for beam positioning, deviation detection, and attitude correction in this field. It can ensure that the surface normal of the sample under test always accurately points to the receiving center of the orientation collimation and gating component during the 0-90° rotation process, and make the angle alignment error less than ±0.05°. It effectively avoids the emission angle deviation of resonant Auger electrons and the drift of detection depth caused by sample attitude deviation.

[0087] The directional collimation and gating assembly includes: a multi-stage adjustable aperture aperture, which is a group of multiple coaxially arranged microaperture apertures with progressively converging apertures, used to progressively screen, match, and output a resonant Auger electron beam with uniform flux and appropriate density; an angle-limiting collimating cylinder, which is a hollow cylindrical structure with a fixed inner diameter and axial length, used to limit the electron receiving solid angle, allowing only resonant Auger electrons emitted at small angles near the sample surface normal to pass through; and a background suppression baffle, which is a ring-shaped light-shielding baffle structure used to block residual scattered electrons and large-angle diffuse reflection electrons in the external region of the directional collimation and gating assembly.

[0088] By employing multiple coaxially arranged microaperture groups with progressively converging apertures, the aperture size of the microaperture group can be adjusted according to testing requirements. By changing the effective size of the aperture, the cross-sectional area of ​​the passing electron beam is constrained, intercepting stray electrons with excessive radial deviation and disordered scattering. This allows for the selection, matching, and output of a resonant Auger electron beam with uniform flux and appropriate density. An angle-limiting collimating cylinder restricts the electron receiving solid angle, allowing only resonant Auger electrons emitted at small angles near the sample surface normal to pass through, while those emitted at large angles deviating from the normal and with inclined transmission trajectories... Scattered electrons at an angle are absorbed and intercepted by the inner wall of the angle-limited collimating tube, forming a fixed electron receiving solid angle threshold, thus limiting the electron receiving solid angle from a geometrical spatial dimension. The background suppression baffle is fixed at the front end of the angle-limited collimating tube and the gap position of the multi-level adjustable aperture stop, blocking the external area of ​​the directional collimating and gating component, thereby filtering out residual scattered electrons and large-angle diffuse reflection electrons in the ultra-high vacuum environment cavity. This effectively suppresses deep signal interference, ensuring that the electron signals entering the electron energy analyzer all come from the outermost atomic layer, significantly improving signal purity and signal-to-noise ratio.

[0089] The electron energy analyzer receives the screened resonant Auger electrons and performs high-precision resolution and signal acquisition of the electron energy. It identifies the electronic energy level structure, orbital hybridization characteristics and defect electronic state information corresponding to Auger electrons of different energies, forming a deep-resolution resonant Auger electron spectrum.

[0090] Specifically, the electron energy analyzer is a commercially available device purchased from ScientaOmicron, model HiPP-2. This electron energy analyzer is a hemispherical electrostatic energy analyzer, which is a standard and universal detection device for Auger electron spectroscopy and X-ray photoelectron spectroscopy in the field of surface analysis.

[0091] Example 2

[0092] Please refer to Figure 3 This embodiment provides a method for nanoscale depth-resolution analysis of polar surfaces, including the following steps:

[0093] S1. Sample pretreatment and vacuum loading: The sample to be tested is cleaned to remove surface oil, dust and adsorbed impurities. The pretreated sample is fixed on a high-precision variable angle sample stage. The ultra-high vacuum environment cavity provides and maintains a working environment with a preset ultra-high vacuum degree. After standing and stabilizing, the sample pretreatment is completed.

[0094] The ultra-high vacuum environment chamber includes: a vacuum chamber for providing an ultra-high vacuum working space; a vacuum valve for achieving staged sealing and gas path switching within the vacuum chamber; a vacuum gauge for real-time monitoring of the vacuum level within the vacuum chamber; and a vacuum pump unit for continuously removing residual gas from the vacuum chamber to maintain the ultra-high vacuum working environment. The ultra-high vacuum environment chamber maintains a vacuum level of 5 × 10⁻⁶. -10 mBar-1×10 -9 The ultra-high vacuum working atmosphere of mBar avoids the adsorption and contamination of samples by air impurities, eliminates the scattering interference of residual gases on low-energy Auger electrons, and ensures stable and lossless transmission of electron signals on the electrode surface, providing a basic environmental guarantee for high-precision electrode surface depth resolution testing.

[0095] S2. Automatic alignment and calibration of sample normals: The sample surface normal self-alignment mechanism is activated to detect and correct the attitude of the high-precision variable angle sample stage, and to control the spatial orientation of the sample surface normals to the receiving center of the orientation collimation gating component, thus completing the attitude calibration before testing.

[0096] The sample surface normal self-alignment mechanism includes: a dual laser reflection alignment unit, used to receive the detection beam reflected from the sample surface and identify the direction of the sample surface normal in real time through the laser reflection of the detection beam; a four-quadrant detector, used to capture the position deviation of the reflected spot of the detection beam; and a closed-loop fine-tuning radio, used to output a control signal according to the position deviation of the reflected spot detected by the four-quadrant detector, drive the high-precision variable angle sample stage to adjust its attitude, and control the spatial orientation of the sample surface normal to the receiving center of the orientation collimation gating component.

[0097] The dual laser reflection alignment unit receives the detection beam reflected from the sample surface, and the laser reflection of the detection beam identifies the normal direction of the sample surface in real time; the four-quadrant detector captures the position deviation of the reflected spot of the detection beam and feeds back the position deviation of the reflected spot; the closed-loop fine-tuning radio outputs a control signal based on the position deviation of the reflected spot fed back by the four-quadrant detector, drives the high-precision variable angle sample stage to adjust its attitude, and controls the spatial orientation of the sample surface normal to the receiving center of the orientation collimation gating component.

[0098] Specifically, the sample surface normal self-alignment mechanism is basically the same as the laser positioning, spot deviation detection, and closed-loop attitude correction mechanism used in existing laser interferometers, precision optical alignment systems, and beam pointing stabilization systems. It is a common method for beam positioning, deviation detection, and attitude correction in this field. It can ensure that the surface normal of the sample under test always accurately points to the receiving center of the orientation collimation and gating component during the 0-90° rotation process, and make the angle alignment error less than ±0.05°. It effectively avoids the emission angle deviation of resonant Auger electrons and the drift of detection depth caused by sample attitude deviation.

[0099] S3. Synchrotron radiation beam modulation and resonant excitation: The synchrotron radiation photonic modulation component receives an external synchrotron radiation broadband beam, which, after monochromaticization, slit modulation and superfocusing, outputs a soft X-ray beam with continuously adjustable energy, monochromaticity and stable brightness. It matches the resonant absorption energy of the element to be measured and performs specific resonant excitation on the 1-2nm polar surface layer of the sample to generate a high-intensity resonant Auger electron signal.

[0100] The synchrotron radiation photon modulation assembly includes: a grating monochromator, used to disperse the synchrotron radiation broadband beam according to photon energy and filter out monochromatic beams of single energy; a slit element, used to spatially confine and intensify the monochromatic beam, eliminating stray light and higher-order diffraction light at the edges, and obtaining a collimated beam with a regular cross-section, small divergence angle, and higher energy purity; and a focusing optical element, used to converge the collimated beam into a focused spot to form a soft X-ray beam with continuously adjustable energy, monochromaticity, and stable brightness.

[0101] When a synchrotron radiation broadband beam passes through a grating monochromator, the continuous broadband beam is dispersed according to photon energy based on Bragg's diffraction theorem. A monochromatic beam with a single central energy and extremely narrow energy bandwidth is selected, achieving precise selection and continuous adjustment of photon energy. When the monochromatic beam passes through a slit element, the slit element spatially confines and intensifies the beam, eliminating stray light and higher-order diffracted light from the edges, resulting in a collimated beam with a regular cross-section, small divergence angle, and higher energy purity. When the collimated beam passes through a focusing optics element, it converges into a small, uniformly sized, concentrated, and stable focused spot, forming a soft X-ray beam with continuously adjustable energy, monochromaticity, and stable brightness. This soft X-ray beam can precisely irradiate the test area on the surface of the sample. The energy of the formed soft X-ray beam can be adjusted to monochromatic light from 100 eV to 1200 eV according to usage requirements, and the size of the focused spot is 0.8*0.3 mm. 2 luminous flux greater than 10 10 phs / s.

[0102] The high-precision variable angle sample stage includes: a rotary drive element, used to drive the sample to rotate continuously within a set angle range to change the angle between the sample surface and the incident soft X-ray beam, and synchronously control the emission angle of resonant Auger electrons; and an attitude adjustment element, used to adjust the spatial orientation of the sample surface normal according to the control signal output by the closed-loop fine-tuning radio.

[0103] The high-precision variable-angle sample stage has the ability to continuously rotate from 0 to 90° and adjust the three-dimensional precision displacement. The rotation angle control accuracy is ±0.01°, which can accurately change the angle between the sample surface and the incident soft X-ray beam, and simultaneously control the emission angle of resonant Auger electrons, thereby changing the electron escape path length. It can realize continuous gradient scanning at the atomic level depth within the 1-2nm polar surface range, providing a precise and controllable angle adjustment basis for polar surface depth resolution detection.

[0104] Specifically, the electron escape depth follows the electron escape depth formula:

[0105]

[0106] In the formula, The mean free path of electron inelastic scattering. The emission angle of the resonant Auger electrons, The smaller the angle, The smaller the value, the shallower the electron escape depth, and vice versa.

[0107] S4. Variable Angle Gradient Scanning and Depth-Resolved Acquisition: The high-precision variable angle sample stage is continuously rotated within a preset step size in the range of 0-90°. Based on the depth conversion relationship, the Auger electron escape depth is continuously changed. The directional collimation gating component filters out large-angle scattered electrons and deep stray electron signals, suppresses deep signal interference, and only allows resonant Auger electrons emitted at small angles near the sample surface normal to pass through. The electron energy analyzer receives the screened resonant Auger electrons and performs high-precision resolution and signal acquisition on the electron energy. It identifies the electronic energy level structure, orbital hybridization characteristics and defect electronic state information corresponding to Auger electrons of different energies, forming a depth-resolved resonant Auger electron spectrum.

[0108] The directional collimation and gating assembly includes: a multi-stage adjustable aperture aperture, which is a group of multiple coaxially arranged microaperture apertures with progressively converging apertures, used to progressively screen, match, and output a resonant Auger electron beam with uniform flux and appropriate density; an angle-limiting collimating cylinder, which is a hollow cylindrical structure with a fixed inner diameter and axial length, used to limit the electron receiving solid angle, allowing only resonant Auger electrons emitted at small angles near the sample surface normal to pass through; and a background suppression baffle, which is a ring-shaped light-shielding baffle structure used to block residual scattered electrons and large-angle diffuse reflection electrons in the external region of the directional collimation and gating assembly.

[0109] By employing multiple coaxially arranged microaperture groups with progressively converging apertures, the aperture size of the microaperture group can be adjusted according to testing requirements. By changing the effective size of the aperture, the cross-sectional area of ​​the passing electron beam is constrained, intercepting stray electrons with excessive radial deviation and disordered scattering. This allows for the selection, matching, and output of a resonant Auger electron beam with uniform flux and appropriate density. An angle-limiting collimating cylinder restricts the electron receiving solid angle, allowing only resonant Auger electrons emitted at small angles near the sample surface normal to pass through, while those emitted at large angles deviating from the normal and with inclined transmission trajectories... Scattered electrons at an angle are absorbed and intercepted by the inner wall of the angle-limited collimating tube, forming a fixed electron receiving solid angle threshold, thus limiting the electron receiving solid angle from a geometrical spatial dimension. The background suppression baffle is fixed at the front end of the angle-limited collimating tube and the gap position of the multi-level adjustable aperture stop, blocking the external area of ​​the directional collimating and gating component, thereby filtering out residual scattered electrons and large-angle diffuse reflection electrons in the ultra-high vacuum environment cavity. This effectively suppresses deep signal interference, ensuring that the electron signals entering the electron energy analyzer all come from the outermost atomic layer, significantly improving signal purity and signal-to-noise ratio.

[0110] The electron energy analyzer receives the screened resonant Auger electrons and performs high-precision resolution and signal acquisition of the electron energy. It identifies the electronic energy level structure, orbital hybridization characteristics and defect electronic state information corresponding to Auger electrons of different energies, forming a deep-resolution resonant Auger electron spectrum.

[0111] Specifically, the electron energy analyzer is a commercially available device purchased from ScientaOmicron, model HiPP-2. This electron energy analyzer is a hemispherical electrostatic energy analyzer, which is a standard and universal detection device for Auger electron spectroscopy and X-ray photoelectron spectroscopy in the field of surface analysis.

[0112] S5. Data Fusion and Polar Surface Characterization Analysis: Normalize, correct, noise-remove and fit peak shapes of multiple sets of angle-depth-electron energy spectrum data of the acquired resonance Auger electron spectrum to construct 1-2nm atomic-level depth-resolution electronic structure spectrum of the polar surface, analyze the electronic state density, orbital hybridization and defect electronic state evolution law of different atomic layers, and complete the high-precision analysis and characterization of the polar surface.

[0113] Specifically, for the collected resonant Auger electron spectrum data, multiple sets of angle-depth-electron energy spectrum data are normalized by returning the edge to 0 and the edge to 1 using the standard processing method for absorption spectra. This unifies the baselines and intensity scales of multiple energy spectra and eliminates intensity deviations caused by test fluctuations. Random abrupt changes and abnormal noise points in the data are identified and removed to eliminate non-physical noise interference and ensure the continuity and reliability of the spectral data. Furthermore, Auger characteristic peaks are fitted using standard methods according to conventional absorption spectrum fitting techniques to accurately extract core parameters such as peak position, peak height, full width at half maximum (FWHM), and peak area, and to correct for minor peak shape distortions.

[0114] Based on the fitted multi-set of angle and depth dimension energy spectrum parameters, and by comparing standard spectroscopic features and electronic structure theory, the electronic state density and orbital hybridization degree of different atomic layers are analyzed by using spectral peak shift, peak broadening and intensity changes commonly used in existing technologies. Combined with the defect-type spectral peak distortion characteristics, the evolution law of defect electronic states with the depth of the polar surface is analyzed.

[0115] Specifically, a shift in peak position towards higher energies corresponds to an increase in elemental valence, a shortening of chemical bonds, and an enhanced degree of orbital hybridization, and vice versa; an increase in peak half-width at half-maximum and a more pronounced broadening correspond to an increase in defect electronic states, an increase in local structural disorder, and an enhanced inhomogeneity of the electronic environment within the atomic layer, and vice versa; an increase in signal intensity corresponds to an increase in the density of electronic states in the corresponding atomic layer, a higher atomic concentration, and an enhanced contribution of the polar surface signal, and vice versa.

[0116] The above description is merely a preferred embodiment of this application and is not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A polar surface nanoscale depth-resolution analysis system, characterized in that, include: Synchrotron radiation photonic modulation assembly, high-precision variable angle sample stage, sample surface normal self-alignment mechanism, orientation collimation gating assembly, electron energy analyzer, and ultra-high vacuum environment chamber; The ultra-high vacuum environment cavity is used to provide and maintain an ultra-high vacuum working environment; The synchrotron radiation photonic modulation component is used to receive a broadband beam of synchrotron radiation, and after monochromatization, slit modulation and focusing, output a soft X-ray beam with continuously adjustable energy, monochromaticity and stable brightness. The high-precision variable-angle sample stage is set in an ultra-high vacuum chamber to stably support the sample to be tested and to adjust the spatial position and angular orientation of the sample to be tested. The sample surface normal self-alignment mechanism is integrated into the high-precision variable angle sample stage. It is used to detect and correct the attitude of the high-precision variable angle sample stage in real time during the angle adjustment process of the high-precision variable angle sample stage, and control the spatial orientation of the sample surface normal to the receiving center of the orientation collimation selection component. The directional collimation and gating component is coaxially arranged between the high-precision variable-angle sample stage and the electron energy analyzer. It is used to filter out large-angle scattered electrons and deep stray electron signals, suppress deep signal interference, and only allow resonant Auger electrons emitted at small angles near the sample surface normal to pass through. The electron energy analyzer is located at the rear end of the directional collimation gating component. It is used to receive the screened resonant Auger electrons, perform high-precision resolution and signal acquisition of the electron energy, identify the electronic energy level structure, orbital hybridization characteristics and defect electronic state information corresponding to Auger electrons of different energies, and form a deep-resolution resonant Auger electron spectrum.

2. The polar surface nanoscale depth resolution analysis system according to claim 1, characterized in that, The synchrotron photonic modulation component includes: A grating monochromator is used to disperse and separate a broadband beam of synchrotron radiation according to photon energy, thereby selecting a monochromatic beam with a single energy. Slit elements are used to spatially confine and intensity-regulate monochromatic beams, eliminating stray light and higher-order diffraction light from the edges, and obtaining collimated beams with regular cross-sections, small divergence angles, and higher energy purity. Focusing optical elements are used to converge a collimated beam into a focused spot, forming a soft X-ray beam with continuously adjustable energy, monochromaticity, and stable brightness.

3. The polar surface nanoscale depth resolution analysis system according to claim 1, characterized in that, The sample surface normal self-alignment mechanism includes: The dual laser reflection alignment unit is used to receive the detection beam reflected from the sample surface and to identify the normal direction of the sample surface in real time through the laser reflection of the detection beam. A four-quadrant detector is used to capture the positional deviation of the reflected spot of the detection beam; A closed-loop fine-tuning radio is used to output a control signal based on the position deviation of the reflected light spot detected by the four-quadrant detector, drive the high-precision variable-angle sample stage to adjust its attitude, and control the spatial orientation of the sample surface normal to the receiving center of the directional collimation gating component.

4. The polar surface nanoscale depth resolution analysis system according to claim 3, characterized in that, The high-precision variable angle sample stage includes: A rotary drive element is used to drive the sample to rotate continuously within a set angle range, so as to change the angle between the sample surface and the incident soft X-ray beam and synchronously control the emission angle of resonant Auger electrons. An attitude adjustment element is used to adjust the spatial orientation of the sample surface normal according to the control signal output by the closed-loop fine-tuning radio.

5. The polar surface nanoscale depth resolution analysis system according to claim 1, characterized in that, The directional collimation and gating component includes: The multi-level adjustable aperture aperture is a group of multiple coaxially arranged micro-aperture apertures with progressively converging apertures, used to progressively screen, match and output a resonant Auger electron beam with uniform flux and appropriate density. Angle-limiting collimating cylinder is a hollow cylindrical structure with a fixed inner diameter and axial length. It is used to limit the electron receiving solid angle, allowing only resonant Auger electrons emitted at a small angle near the normal to the sample surface to pass through. The background suppression baffle is a ring-shaped light-shielding baffle structure used to block residual scattered electrons and large-angle diffuse reflection electrons in the outer region of the directional collimation gating component.

6. The polar surface nanoscale depth resolution analysis system according to claim 1, characterized in that, The ultra-high vacuum environment cavity includes: Vacuum chambers are used to provide ultra-high vacuum working spaces; A vacuum valve is used to achieve graded sealing and gas path switching within the vacuum chamber; A vacuum gauge is used to monitor the vacuum level inside the vacuum chamber in real time. The vacuum pump unit is used to continuously remove residual gas from the vacuum chamber and maintain the ultra-high vacuum working environment within the vacuum chamber.

7. A resolution analysis method for a polar surface nanoscale depth resolution analysis system according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Sample pretreatment and vacuum loading: The sample to be tested is cleaned to remove surface oil, dust and adsorbed impurities. The pretreated sample is fixed on a high-precision variable angle sample stage. The ultra-high vacuum environment cavity provides and maintains a working environment with a preset ultra-high vacuum degree. After standing and stabilizing, the sample pretreatment is completed. S2. Automatic alignment and calibration of sample normals: The sample surface normal self-alignment mechanism is activated to detect and correct the attitude of the high-precision variable angle sample stage, and to control the spatial orientation of the sample surface normals to the receiving center of the orientation collimation selection component, thus completing the attitude calibration before testing. S3. Synchrotron radiation beam modulation and resonant excitation: The synchrotron radiation photonic modulation component receives an external synchrotron radiation broadband beam, which, after monochromaticization, slit modulation and superfocusing, outputs a soft X-ray beam with continuously adjustable energy, monochromaticity and stable brightness. It matches the resonant absorption energy of the element to be measured and performs specific resonant excitation on the 1-2nm polar surface layer of the sample to generate a high-intensity resonant Auger electron signal. S4. Variable Angle Gradient Scanning and Depth-Resolved Acquisition: The high-precision variable angle sample stage is continuously rotated within a preset step size in the range of 0-90°. Based on the depth conversion relationship, the Auger electron escape depth is continuously changed. The directional collimation gating component filters out large-angle scattered electrons and deep stray electron signals, suppresses deep signal interference, and only allows resonant Auger electrons emitted at small angles near the sample surface normal to pass through. The electron energy analyzer receives the screened resonant Auger electrons and performs high-precision resolution and signal acquisition on the electron energy. It identifies the electronic energy level structure, orbital hybridization characteristics, and defect electronic state information corresponding to Auger electrons of different energies, forming a depth-resolved resonant Auger electron spectrum. S5. Data Fusion and Polar Surface Characterization Analysis: Normalize, correct, noise-remove and fit peak shapes of multiple sets of angle-depth-electron energy spectrum data of the acquired resonance Auger electron spectrum to construct 1-2nm atomic-level depth-resolution electronic structure spectrum of the polar surface, analyze the electronic state density, orbital hybridization and defect electronic state evolution law of different atomic layers, and complete the high-precision analysis and characterization of the polar surface.

8. The method for nanoscale depth-resolution analysis of polar surfaces according to claim 7, characterized in that, The activation of the sample surface normal self-alignment mechanism, and the detection and correction of the high-precision variable-angle sample stage attitude, include: The dual laser reflection alignment unit receives the detection beam reflected from the sample surface, and the laser reflection of the detection beam identifies the normal direction of the sample surface in real time. The four-quadrant detector captures the position deviation of the reflected light spot of the detection beam and feeds back the position deviation of the reflected light spot; The closed-loop fine-tuning radio outputs a control signal based on the position deviation of the reflected light spot fed back by the four-quadrant detector, which drives the high-precision variable-angle sample stage to adjust its attitude and control the spatial orientation of the sample surface normal to the receiving center of the orientation collimation gating component.

9. The method for nanoscale depth-resolution analysis of polar surfaces according to claim 7, characterized in that, The received synchrotron radiation broadband beam, after monochromaticization, slit modulation, and superfocusing, outputs a soft X-ray beam with continuously adjustable energy, stable monochromaticity, and stable brightness, comprising: The grating monochromator disperses the received external synchrotron radiation broadband beam according to photon energy, and filters out monochromatic beams with single energy. The slit element spatially confines and intensifies the monochromatic beam, eliminating stray light from the edges and higher-order diffraction light, and obtaining a collimated beam with a regular cross-section, small divergence angle, and higher energy purity. Focusing optical elements converge the collimated beam into a focused spot, forming a soft X-ray beam with continuously adjustable energy, monochromaticity, and stable brightness.

10. The method for nanoscale depth-resolution analysis of polar surfaces according to claim 7, characterized in that, The process of filtering out large-angle scattered electrons and deep-layer stray electron signals, suppressing deep-layer signal interference, and allowing only resonant Auger electrons emitted at small angles near the sample surface normal to pass through includes: Through the multi-stage adjustable aperture aperture group with multiple coaxial arrangement and progressively converging apertures, a resonant Auger electron beam with uniform flux and appropriate density is output by step-by-step screening, matching and output. Angle-limiting collimating cylinder restricts the electron receiving solid angle, allowing only resonant Auger electrons emitted at small angles near the sample surface normal to pass through; Background suppression baffles block residual scattered electrons and large-angle diffuse reflection electrons in the outer region of the directional collimation gating component.

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