Longitudinal space analysis method of multi-quantum well semiconductor element
By combining TOF-SIMS with an optical system, the challenge of measuring the longitudinal spatial optical properties of semiconductor devices has been solved, enabling fine spectral analysis of structures such as quantum wells and quantum dots, and improving the accuracy and precision of the measurements.
Patent Information
- Application Number
- CN202410463957.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-17
- Publication Date
- 2025-10-24
AI Technical Summary
In the existing technology, the analysis of semiconductor devices is mainly focused on the lateral direction, making it difficult to achieve accurate and precise measurement of the optical properties of quantum well materials in the vertical space, which is limited by the nanoscale structural characteristics of the multilayer overlapping arrangement.
TOF-SIMS was used to perform ion sputtering etching on the surface of semiconductor devices at an angle relative to the stacking direction. Raman and photoluminescence spectroscopy measurements were performed using an optical system. The optical properties in the longitudinal space were determined by super-resolution microscopy, and the transfer and analysis were performed using a vacuum interconnect system.
This technology enables the characterization of the optical properties of semiconductor devices in the vertical space, improving the accuracy and precision of measurements. It can be applied to the optical property analysis of quantum wells, quantum dots, and other epitaxially grown semiconductor heterostructures.
Smart Images
Figure CN120834025A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of semiconductor device analysis, and specifically relates to a longitudinal spatial analysis method for a multi-quantum well semiconductor element. Background Art
[0002] Raman spectroscopy and photoluminescence (PL) spectroscopy are optical measurement methods that are non-destructive, non-contact, and require no additional processing. They can analyze samples non-destructively and accurately and are widely used to study the composition, impurities, defects, structure, and polarization effects of semiconductor materials.
[0003] Currently, most reports on the analysis of semiconductor devices focus on lateral characterization and analysis, comparing the compositional distribution of semiconductor cross-sections with the Raman and photoluminescence spectra of semiconductor materials to determine the correlation between luminescence properties and subtle differences in luminescence characteristics caused by different micro-region morphologies. Due to technical and equipment limitations, detailed reports on the optical properties of quantum wells in the longitudinal direction are rare. Furthermore, the inherent multi-layered, overlapping structure of quantum well materials, with each functional layer mostly at the nanometer scale, pose challenges in ensuring accurate and precise measurements. Summary of the Invention
[0004] The purpose of this application is to provide a longitudinal spatial analysis method for multi-quantum well semiconductor elements to solve the problem that the existing technology can only achieve lateral characterization and analysis of semiconductor elements. Since the quantum well material itself has the structural characteristics of multi-layer overlapping arrangement, and most of the functional layers are at the nanometer scale, it brings difficulties to ensure the accuracy and precision of the measurement, and it is difficult to achieve analysis of the optical properties of the quantum well in the longitudinal space.
[0005] In order to achieve the above objectives, the technical solution adopted in this application is:
[0006] A longitudinal spatial analysis method for a multi-quantum well semiconductor element is provided, comprising:
[0007] Using TOF-SIMS, ion sputter etching is performed on the surface of the semiconductor element in a direction inclined relative to the stacking direction until the template layer of the semiconductor element is etched, thereby obtaining an etched pit with sidewalls exposing the cover layer, quantum well layer, and template layer of the semiconductor element;
[0008] transferring the semiconductor element to a sample stage of an optical system;
[0009] Determine the area where the etch pit is located based on a super-resolution microscope, and perform Raman spectrum and photoluminescence spectrum measurement on the area where the etch pit is located to obtain a Raman spectrum map and a photoluminescence spectrum map;
[0010] The corresponding areas of the cover plate layer, the quantum well layer and the template layer are determined on the Raman spectrum and the photoluminescence spectrum, and a longitudinal spatial spectrum analysis diagram of the semiconductor element is obtained.
[0011] In one or more embodiments, the TOF-SIMS and the optical system are located in a vacuum interconnection system and are connected through an ultrahigh vacuum pipeline.
[0012] The step of transferring the semiconductor element to the sample stage of the optical system specifically includes transferring the semiconductor element to the sample stage of the optical system through the ultrahigh vacuum pipeline.
[0013] In one or more embodiments, in the step of performing ion sputtering etching on the surface of the semiconductor element along a direction inclined relative to the stacking direction using TOF-SIMS, the direction of ion sputtering etching is inclined by 45° relative to the stacking direction.
[0014] In one or more embodiments, in the step of performing ion sputtering etching on the surface of the semiconductor element along a direction inclined relative to the stacking direction using TOF-SIMS until the template layer of the semiconductor element is etched, the method of controlling etching to the template layer of the semiconductor element includes:
[0015] In the ion sputtering etching, secondary ions are collected and analyzed in real time to obtain real-time secondary ion data, real-time etching layer data is determined based on the real-time secondary ion data, and etching to the template layer of the semiconductor element is controlled based on the real-time etching layer data.
[0016] In one or more embodiments, in the step of performing ion sputtering etching on the surface of the semiconductor element along a direction inclined relative to the stacking direction using TOF-SIMS, the sputtering source of ion sputtering etching is CS+ with an energy of 1 KeV and a beam current of 80 nA.
[0017] In one or more embodiments, in the step of performing Raman spectrum and photoluminescence spectrum measurement on the area where the etching pit is located, the laser wavelength of spectrum measurement is 532 nm, the power is 50 mW, and the laser spot is 100 nm.
[0018] In one or more embodiments, the step of determining the corresponding areas of the cover plate layer, the quantum well layer and the template layer on the Raman spectrum and the photoluminescence spectrum specifically includes:
[0019] Based on the structural characteristics of the semiconductor element and the etch pit, the corresponding areas of the cover layer, quantum well layer and template layer on the Raman spectrum and photoluminescence spectrum are calculated in proportion. The structural characteristics of the semiconductor element include the thickness of the cover layer, quantum well layer and template layer, and the structural characteristics of the etch pit include the slope of the side wall of the etch pit and the width of the etch pit.
[0020] In one or more embodiments, further comprising:
[0021] Raman spectroscopy scanning and photoluminescence spectroscopy scanning are performed from the surface of the semiconductor element along the sidewall of the etch pit to the bottom of the etch pit to obtain scanning data, and a 2D spectral image corresponding to the spatial dimensions of the layered structure of the sidewall of the etch pit is drawn based on the scanning data.
[0022] In one or more embodiments, in the step of obtaining a 2D spectral image corresponding to the spatial size of the layered structure of the sidewall of the etch pit based on the scanning data, the drawing is specifically performed by using origin software.
[0023] Different from the prior art, the present invention has the following advantages:
[0024] This application combines TOF-SIMS ion sputtering etching with optical system spectral measurement to achieve longitudinal spatial optical performance characterization and analysis of semiconductor components. It can give full play to the fine spatial resolution capability of ultra-high vacuum optical systems and the sensitive detection capability of time-of-flight secondary ion mass spectrometer (TOF-SIMS), and achieve a characterization effect that correlates material structure and luminescence performance.
[0025] The characterization method of the present application is universal and can be applied to characterize the optical properties of quantum wells, quantum dots and other types of epitaxially grown semiconductor heterostructures, opening up a new idea for measuring fine spectra in the longitudinal space. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] To more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.
[0027] Figure 1 This is a schematic flow chart of an embodiment of a longitudinal spatial analysis method for a multi-quantum well semiconductor device of the present application;
[0028] Figure 2is a schematic diagram of an embodiment of an etching pit of a semiconductor element after ion sputtering etching according to the present application;
[0029] Figure 3 is a structural schematic diagram of an embodiment of a semiconductor element according to the present application. DETAILED DESCRIPTION
[0030] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.
[0031] The characterization analysis of the conventional semiconductor element is limited to the lateral characterization. Due to the limitations of technology and equipment, there are few reports on the analysis of the optical performance of the quantum well in the longitudinal space. At the same time, due to the structural characteristics of the quantum well material itself with multiple layers of superimposed arrangement, and most of the functional layers are in the scale of nanometers, these all bring difficulties to ensure the accuracy and precision of the measurement.
[0032] In order to overcome the technical difficulties of the above-mentioned conventional measurement, the applicant has developed a method for characterizing the optical performance of the longitudinal space of a semiconductor element, and the characterization method can be applied to characterize the optical properties of quantum wells, quantum dots and other types of epitaxially grown semiconductor heterostructures, overcoming the technical difficulties of conventional measurement, and having a breakthrough significance for realizing the measurement of fine spectra of different depth profiles.
[0033] Specifically, please refer to Figure 1 , Figure 1 is a flowchart of an embodiment of a method for analyzing the longitudinal space of a multi-quantum well semiconductor element according to the present application.
[0034] As Figure 1 shown, the analysis method comprises:
[0035] S100, using TOF-SIMS to perform ion sputtering etching on the surface of the semiconductor element along a direction inclined with respect to the stacking direction until the template layer of the semiconductor element is etched, to obtain an etching pit exposing the cover plate layer, the quantum well layer and the template layer of the semiconductor element.
[0036] Firstly, ion sputtering etching can be performed on the surface of the semiconductor element based on the time-of-flight secondary ion mass spectrometer TOF-SIMS, and the etching direction is arranged to be inclined with respect to the stacking direction of the semiconductor element until the template layer of the semiconductor element is etched, so as to ensure that the etching pit obtained by etching can expose the cover plate layer, the complete quantum well layer and the template layer of the semiconductor element.
[0037] Please refer to Figure 2 , Figure 2 is a schematic diagram of an embodiment of the etching pit of the semiconductor element after ion sputtering etching.
[0038] As shown in Figure 2 , the sidewall of the etching pit obtained by etching is inclined and exposes the cap layer, the quantum well layer and the template layer.
[0039] In an embodiment, in order to ensure the complete exposure of each functional layer and ensure the etching precision, the etching direction can be inclined by 45° relative to the stacking direction of the semiconductor layer.
[0040] In an embodiment, the TOF-SIMS used can be TOF.SIMS5-100, and the sputtering source of ion sputtering etching can be CS+ with an energy of 1 KeV, and the beam current can be 80 nA.
[0041] S200, transferring the semiconductor element to the sample stage of the optical system.
[0042] After etching is completed, the semiconductor element can be transferred to the optical system for subsequent optical performance analysis of the exposed functional layers.
[0043] In an embodiment, in order to ensure the cleanliness of the etching surface and avoid the influence of air adsorption on the optical performance analysis structure, the TOF-SIMS and the optical system can be located in a vacuum interconnection system and connected through an ultrahigh vacuum pipeline. The semiconductor element can be transferred between the vacuum environment to the sample stage of the optical system based on the ultrahigh vacuum pipeline.
[0044] In an embodiment, in order to accurately control the etching depth of ion sputtering etching and ensure etching to the template layer, real-time secondary ions can be collected and analyzed in ion sputtering etching to obtain real-time secondary ion data. Based on the real-time secondary ion data, real-time etching layer data is determined, and based on the real-time etching layer data, etching to the template layer of the semiconductor element is controlled.
[0045] For example, as shown in Figure 3 , an InGaN quantum well semiconductor element is taken as an example, Figure 3 is a structural schematic diagram of an embodiment of the semiconductor element. Since the Al content of the known template layer is higher than the In component content of the cap layer and the quantum well layer, based on the real-time secondary ion data, the accuracy of the etching depth can be confirmed, and the etching bottom surface is ensured to be located in the template layer, thereby ensuring the complete exposure of each functional layer.
[0046] S300, determining the region where the etching pits are located based on the super-resolution microscope, and performing Raman spectrum and photoluminescence spectrum measurement on the region where the etching pits are located to obtain a Raman spectrum graph and a photoluminescence spectrum graph.
[0047] In the optical system, the region where the etching pits are located can be first determined by the super-resolution microscope, and after locating the etching region, the optical performance analysis can be performed on the region where the etching pits are located.
[0048] The optical performance analysis can include Raman spectrum analysis and photoluminescence spectrum measurement, so as to obtain the Raman spectrum graph and the photoluminescence spectrum graph of the region where the etching pits are located.
[0049] In one embodiment, the laser wavelength of the spectrum measurement can be 532 nm, the power can be 50 mW, and the laser spot can be 100 nm.
[0050] In other embodiments, the laser wavelength, power and spot size can also be adjusted based on actual working conditions.
[0051] S400, determining the corresponding regions of the cover plate layer, the quantum well layer and the template layer from the Raman spectrum graph and the photoluminescence spectrum graph to obtain a longitudinal spatial spectrum analysis graph of the semiconductor element.
[0052] The corresponding regions of each layer are determined on the obtained Raman spectrum graph and photoluminescence spectrum graph, so that the longitudinal spatial spectrum analysis graph of the semiconductor element can be obtained.
[0053] Specifically, the method of confirming the corresponding regions of each layer can be to calculate the corresponding regions of the cover plate layer, the quantum well layer and the template layer on the Raman spectrum graph and the photoluminescence spectrum graph based on the structural characteristics of the semiconductor element and the etching pits in a proportional relationship.
[0054] The structural characteristics of the semiconductor element include the thicknesses of the cover plate layer, the quantum well layer and the template layer, and the structural characteristics of the etching pits include the slope of the sidewall of the etching pit and the width of the etching pit.
[0055] For example, when the thickness of the cover plate layer is known to be 5 nm, the thickness of the quantum well layer is 20 nm, the width of the etching pit is 100 nm, and the inclination angle of the sidewall of the etching pit is 45°, the width of the corresponding regions of the cover plate layer and the quantum well layer on the spectrum graph can be calculated to be 7.07 nm and 28.28 nm respectively based on the Pythagorean theorem. Further, since the width of the template layer corresponding region is 100 nm, the corresponding regions of each functional layer can be determined from the spectrum graph to obtain the longitudinal spatial spectrum analysis graph of the semiconductor element.
[0056] In one embodiment, in order to obtain detailed information about the light emission changes of each layer of the semiconductor element, the analysis method can further include:
[0057] S500, performing Raman spectrum scanning and photoluminescence spectrum scanning from the surface of the semiconductor element along the sidewall of the etching pit to the bottom surface of the etching pit to obtain scanning data, and drawing a 2D spectrum image corresponding to the spatial size of the layered structure of the sidewall of the etching pit based on the scanning data.
[0058] Specifically, the scanning data with spatial size effect can be obtained by the method of spectrum scanning, the scanning data calculates the light emission change of different functional layers, and the scanning data can be drawn into a 2D spectrum image corresponding to the spatial size of the layered structure of the sidewall of the etching pit.
[0059] In one embodiment, the method of drawing a 2D spectrum image based on the scanning data can be drawn by origin software.
[0060] Based on the above longitudinal spatial analysis method, the fine spatial resolution capability of the ultrahigh vacuum optical system and the sensitive detection capability of the time-of-flight secondary ion mass spectrometer (TOF-SIMS) can be fully utilized, the optical performance characterization of the longitudinal space of the semiconductor element is realized, and the characterization effect of associating the material structure and the light emission performance is realized. In addition, this characterization strategy has universality and can be applied to characterize the optical properties of quantum wells, quantum dots and other types of epitaxially grown semiconductor heterostructures, and opens up a new way of thinking for measuring the fine spectrum of the longitudinal space.
[0061] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and scope of the equivalent elements of the claims. Any reference signs in the claims should not be considered as limiting the claims to which they relate.
[0062] In addition, it should be understood that although the present specification is described in terms of embodiments, each embodiment does not contain only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments which can be understood by those skilled in the art.
Claims
1. A method for longitudinal spatial analysis of a multiple quantum well semiconductor element, characterized by, The application relates to a method for analyzing a semiconductor element. The method comprises the following steps: adopting TOF-SIMS to perform ion sputtering etching on the surface of the semiconductor element along a direction inclined to the stacking direction until the template layer of the semiconductor element is etched, so as to obtain an etching pit in which the side wall of the etching pit exposes the cover plate layer, the quantum well layer and the template layer of the semiconductor element; transferring the semiconductor element to the sample table of an optical system; determining the area where the etching pit is located based on a super-resolution microscope, and performing Raman spectrum and photoluminescence spectrum measurement on the area where the etching pit is located, so as to obtain a Raman spectrum graph and a photoluminescence spectrum graph; 2. The longitudinal spatial analysis method according to claim 1, characterized in that, determining the corresponding areas of the cover plate layer, the quantum well layer and the template layer based on the Raman spectrum graph and the photoluminescence spectrum graph, so as to obtain a longitudinal spatial spectrum analysis graph of the semiconductor element. The TOF-SIMS and the optical system are located in a vacuum interconnection system and are connected through an ultrahigh vacuum pipeline; 3. The longitudinal spatial analysis method according to claim 1, characterized by, The step of transferring the semiconductor element to the sample table of the optical system is specifically transferring the semiconductor element to the sample table of the optical system through the ultrahigh vacuum pipeline.
4. The longitudinal spatial analysis method according to claim 1, characterized by, In the step of adopting TOF-SIMS to perform ion sputtering etching on the surface of the semiconductor element along a direction inclined to the stacking direction, the direction of the ion sputtering etching is inclined to the stacking direction by 45 degrees. The method for controlling the etching to the template layer of the semiconductor element in the step of adopting TOF-SIMS to perform ion sputtering etching on the surface of the semiconductor element along a direction inclined to the stacking direction until the template layer of the semiconductor element is etched comprises the following steps:
5. The longitudinal spatial analysis method according to claim 1, characterized by, collecting and analyzing secondary ions in real time during ion sputtering etching to obtain real-time secondary ion data, determining real-time etching layer data based on the real-time secondary ion data, and controlling the etching to the template layer of the semiconductor element based on the real-time etching layer data.
6. The longitudinal spatial analysis method according to claim 1, characterized in that: In the step of adopting TOF-SIMS to perform ion sputtering etching on the surface of the semiconductor element along a direction inclined to the stacking direction, the sputtering source of the ion sputtering etching is CS+ with an energy of 1 KeV and a beam current of 80 nA.
7. The longitudinal spatial analysis method of claim 1, wherein, In the step of performing Raman spectrum and photoluminescence spectrum measurement on the area where the etching pit is located, the laser wavelength of the spectrum measurement is 532 nm, the power is 50 mW, and the laser spot is 100 nm. The step of determining the corresponding areas of the cover plate layer, the quantum well layer and the template layer based on the Raman spectrum graph and the photoluminescence spectrum graph comprises the following steps:
8. The longitudinal spatial analysis method of claim 1, wherein, based on the structural characteristics of the semiconductor element and the etching pit, the corresponding areas of the cover plate layer, the quantum well layer and the template layer on the Raman spectrum graph and the photoluminescence spectrum graph are calculated in a proportional relationship, the structural characteristics of the semiconductor element include the thicknesses of the cover plate layer, the quantum well layer and the template layer, and the structural characteristics of the etching pit include the slope of the side wall of the etching pit and the width of the etching pit. The application further relates to a method for analyzing a semiconductor element. performing Raman spectrum scanning and photoluminescence spectrum scanning along the side wall of the etching pit from the surface of the semiconductor element until the bottom surface of the etching pit is reached, so as to obtain scanning data, and drawing a 2D spectrum image corresponding to the spatial size of the layered structure of the side wall of the etching pit based on the scanning data.
9. The longitudinal spatial analysis method according to claim 8, characterized in that, In the step of drawing a 2D spectral image corresponding to the spatial size of the layer structure of the sidewall of the etching pit based on the scanning data, the drawing is specifically drawing by using origin software. In the step of drawing a 2D spectral image corresponding to the spatial size of the layer structure of the sidewall of the etching pit based on the scanning data, the drawing is specifically drawing by using origin software.