Method and system for analyzing and evaluating interface quality of easy-to-oxidize semiconductor epitaxial film

Abstract

The invention belongs to the technical field of semiconductors, and provides a method and a system for analyzing and evaluating the interface quality of an easy-to-oxidize semiconductor epitaxial thin film, and the method comprises the following steps: firstly, screening a proper material in an oxidation state through the measurement of surface potential by utilizing the operation atmosphere of high-purity inert gas, and then, carrying out differential capacitance measurement, and carrying out difference or differential processing on the measurement result to obtain related information of the interface of the material. The method is convenient to implement, high in measurement reliability and non-loss in detection, is suitable for an easily oxidized semiconductor epitaxial film, and supports high-space electrical measurement and analysis in a low-oxygen environment; the nano-scale high spatial resolution is realized, and the electrical property change of a tiny area at an interface can be captured; the method is of great significance in evaluating and analyzing the quality of the epitaxial interface of the semiconductor material and predicting and optimizing the device performance of related materials.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and specifically relates to a method and system for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial films, especially to a method and system for evaluating the quality of the oxidation of easily oxidized semiconductor materials and their epitaxy, such as the interface between the film and the substrate. Background Art

[0002] The interface quality between the film and the substrate has a significant impact on the performance of easily oxidized semiconductor materials. Easy oxidation semiconductors refer to semiconductor materials that easily react with oxygen to form oxide films when exposed to an oxygen atmosphere. Generally, easily oxidized semiconductors have the characteristics of low bond strength, high hanging bond density, and low potential energy. In applications such as photodetectors and power electronic devices, the interface quality directly determines the carrier transmission efficiency, the response speed of the device, and the overall stability. For example, defects at the interface may cause carrier scattering and recombination, thereby reducing the quantum efficiency and dynamic characteristics of the device. In addition, the interface quality will also affect the reliability of the device under extreme conditions such as high temperature and high electric field. Therefore, accurately evaluating and optimizing the interface quality between the film and the substrate is crucial to improving the performance of easily oxidized semiconductor materials.

[0003] Traditional analysis methods have many limitations in evaluating the interface quality of easily oxidized semiconductor films. Common methods include X-ray diffraction (XRD), transmission electron microscopy (TEM), etc. Although these methods can provide interface structure information, they require a complex sample preparation process and the equipment cost is high. For example, the patent document "High-throughput X-ray Diffraction Analysis Method for Oxide Semiconductor Epitaxial Films" (CN1563958A) discloses the use of a high-throughput fine-beam X-ray diffractometer to prepare a sample library, test basic data, and calculate structural data to achieve testing and analysis of structural parameters such as crystal orientation, lattice strain, and grain size of semiconductor epitaxial films. In addition, these technologies focus on macroscopic or microstructural analysis and are difficult to directly characterize the electrical properties at the interface. For example, XRD mainly reflects lattice parameters and crystallinity, and TEM can observe microscopic defects, but neither can directly obtain key electrical parameters such as carrier concentration and local potential distribution at the interface, which are crucial to understanding the charge transport mechanism at the interface and its impact on device performance.

[0004] Scanning probe technology offers new insights into the interface analysis of readily oxidizable semiconductor films. Kelvin probe force microscopy (KPFM) precisely characterizes the charge distribution and work function changes on the material surface by detecting the surface contact potential difference. Scanning capacitance microscopy (SCM) directly measures the electrical properties at the interface with nanometer-scale resolution, and its high sensitivity can capture minute electrical changes. However, the application of these technologies to the analysis of readily oxidizable semiconductor material interfaces is still in the exploratory stage, and a systematic methodology has yet to be established. This has limited their application in industry and the further improvement of material interface quality.

[0005] The patent document "Evaluation Method of Oxide Semiconductor Thin Films and Quality Management Method of Oxide Semiconductor Thin Films" (CN102313849A) discloses a method for evaluating and measuring the electrical properties of oxide semiconductor films in a non-contact manner without electrodes. Although the mobility of oxide semiconductors of various compositions can be evaluated in a short time and at low cost in the open stage, it also lacks key electrical parameters such as the carrier concentration at the interface and the local potential distribution.

[0006] Therefore, there is an urgent need for a method and system for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial films, which can provide spatial electrical information between the substrate and the epitaxial semiconductor film, and help evaluate and analyze the quality of the epitaxial interface of semiconductor materials, and predict and optimize the device performance of related materials. Summary of the Invention

[0007] In view of the defects in the prior art, the purpose of the present invention is to provide a method and system for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial thin films.

[0008] The method for analyzing and evaluating the interface quality of an easily oxidizable semiconductor epitaxial film provided by the present invention comprises:

[0009] Step S1, making an atmosphere operation box and preparing a low oxygen atmosphere;

[0010] Step S2, preparing a sample in an atmosphere operation box;

[0011] Step S3, measuring the potential of the sample surface in a low-oxygen atmosphere to obtain a potential measurement result;

[0012] Step S4: Based on the material properties of the sample and the potential measurement results, a scanning capacitance test is performed on the sample in a low-oxygen atmosphere, and the measurement results are processed and analyzed.

[0013] Preferably, the atmosphere operation box includes an oxygen monitoring device, a cleavage platform, a cleavage tool, a high-purity inert gas interface, a glove interface and a gas circulation system.

[0014] The low oxygen atmosphere has an oxygen content of less than 2%.

[0015] In step S1, the sample material is placed in an operating box, high-purity inert gas is introduced, and the value of the oxygen monitoring device is observed, and the monitoring stops when the value reaches 2.

[0016] In step S4, a sample oxidized for a suitable time is selected, and a scanning capacitance test is performed in a low-oxygen atmosphere using an electrical measurement mode of a scanning probe microscope to measure the differential capacitance distribution at the sample interface, and the measurement results are processed and analyzed.

[0017] Preferably, the electrical measurement mode includes a conductive atomic force microscopy mode, a Kelvin probe force microscopy mode and a scanning capacitance microscopy mode.

[0018] The interface is the interface region between the substrate and the epitaxial layer.

[0019] The processing and analysis is to analyze the electrical characteristics through difference calculation and differential processing. If the value of the differential capacitance signal is evenly distributed without obvious signal peaks, it indicates that the film quality is good. If the value of the differential capacitance signal has obvious signal peaks, the film quality is poor.

[0020] The scanning capacitance test uses a Si probe with a diamond conductive coating, and irradiates the cantilever with a light spot from a scanning capacitance microscope system. The value of the reflected signal is greater than 3.0, and the AC bias voltage is 1V.

[0021] The measurement result is the value of the scanning capacitance signal of the sample carrier distribution characteristic recorded by the loop.

[0022] Preferably, step S2 includes a pretreatment step and an oxidation step.

[0023] In the pretreatment step, the sample is cleaved along the natural cleavage plane in a low-oxygen atmosphere to form a nanometer-level flat surface and placed vertically upward, with the bottom fixed on the iron sheet by a conductive material to form a common electrode.

[0024] The nanoscale flat surface is a cross-section with a root mean square roughness of less than 0.2 nm.

[0025] During the oxidation step, oxygen is introduced and calibrated, and timing is started to maintain the oxygen content in the atmosphere operation box at a constant value within a specified time, and a KPFM test is performed.

[0026] Preferably, in step S3, surface potential measurements are performed on samples after different oxidation times, and the oxidation state is determined using a scanning probe microscope to obtain and process the potential measurement results.

[0027] The potential measurement results include the substrate side potential and the epitaxial side potential, and the potential difference between the substrate and the epitaxial film is obtained by processing.

[0028] The surface potential test uses an Rtesp probe with a drive amplitude of 8000 mV.

[0029] The process includes calculating and comparing the potential difference between the substrate and the epitaxial film for samples with different oxidation times. When the potential difference is less than a set value, step S4 is executed.

[0030] According to the present invention, a system for analyzing and evaluating the interface quality of an easily oxidized semiconductor epitaxial film is provided, which comprises an atmosphere operation box, a substrate, a scanning capacitance microscopy measurement circuit and a probe cantilever.

[0031] The substrate is located in an atmosphere operating box and is connected to the probe cantilever via a scanning capacitance microscopy measurement circuit;

[0032] Maintain a low oxygen atmosphere in the atmosphere operation box.

[0033] The atmosphere operation box integrates oxygen monitoring equipment, a cleavage platform, a cleavage tool, a high-purity inert gas interface, a glove interface and a gas circulation system.

[0034] Preferably, the sample is prepared in an atmosphere operation box, and the potential measurement is performed to obtain the potential measurement result;

[0035] According to the material properties of the sample and the potential measurement results, the sample is subjected to a scanning capacitance test in a low-oxygen atmosphere, and the measurement results are processed and analyzed.

[0036] The low oxygen atmosphere has an oxygen content of less than 2%.

[0037] The preparation of the low oxygen atmosphere is to place the sample material in an operating box, introduce high-purity inert gas, observe the value of the oxygen monitoring device, and stop when the monitoring value reaches 2.

[0038] The scanning capacitance test selects a sample oxidized for a suitable time, performs the scanning capacitance test in a low-oxygen atmosphere using an electrical measurement mode of a scanning probe microscope to measure the differential capacitance distribution at the sample interface, and processes and analyzes the measurement results.

[0039] Preferably, the electrical measurement mode includes a conductive atomic force microscopy mode, a Kelvin probe force microscopy mode, and a scanning capacitance microscopy mode;

[0040] The interface is the interface region between the substrate and the epitaxial layer.

[0041] The processing and analysis is to analyze the electrical characteristics through difference calculation and differential processing. If the value of the differential capacitance signal is evenly distributed without obvious signal peaks, it indicates that the film quality is good. If the value of the differential capacitance signal has obvious signal peaks, the film quality is poor.

[0042] The scanning capacitance test uses a Si probe with a diamond conductive coating, and irradiates the light spot in the scanning capacitance microscope system on the probe cantilever. The value of the reflected signal is greater than 3.0, and the AC bias voltage is 1V.

[0043] The measurement result is the value of the scanning capacitance signal of the sample carrier distribution characteristic recorded by the loop.

[0044] Preferably, the sample preparation includes a pretreatment operation and an oxidation operation.

[0045] The pretreatment operation is to cleave the sample along the natural cleavage plane in a low-oxygen atmosphere to form a nanometer-level flat surface and place it vertically upward, with the bottom fixed on the iron sheet through a conductive material to form a common electrode.

[0046] The nanoscale flat surface is a cross-section with a root mean square roughness of less than 0.2 nm.

[0047] The oxidation operation is to introduce oxygen and calibrate it, start timing, keep the oxygen content in the atmosphere operation box at a constant value within a specified time, and perform KPFM testing.

[0048] Preferably, the potential measurement is to measure the surface potential of samples after different oxidation times, determine the oxidation state using a scanning probe microscope, obtain the potential measurement results and process them.

[0049] The potential measurement results include the substrate side potential and the epitaxial side potential, and the potential difference between the substrate and the epitaxial film is obtained by processing.

[0050] The surface potential test uses an Rtesp probe with a drive amplitude of 8000 mV.

[0051] The process includes calculating and comparing the potential difference between the substrate and the epitaxial film for samples with different oxidation times, and performing scanning capacitance measurement when the potential difference is smaller than a set value.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] 1. The present invention is easy to implement, has high measurement reliability and non-destructive detection, can be repeated, is applicable to easily oxidized semiconductor epitaxial films to prevent excessive oxidation of the cross section, and supports high-space electrical measurement and analysis in a low-oxygen environment.

[0054] 2. The present invention combines surface potential measurement with the screening of materials with appropriate oxidation degrees for scanning capacitance testing. It has nanoscale high spatial resolution, can capture changes in electrical properties in tiny areas at the interface, and finely depict local differences in interface quality.

[0055] 3. The present invention obtains minority carrier distribution information inside semiconductor materials by performing difference calculations and differential calculations on carrier distribution information, which is of great significance for evaluating and analyzing the quality of the epitaxial interface of semiconductor materials and predicting and optimizing the device performance of related materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0057] Figure 1 Schematic diagram of the system structure for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial films.

[0058] Figure 2 Schematic diagram of the analysis and evaluation method and system for the interface quality of easily oxidized semiconductor epitaxial films.

[0059] Figure 3 Schematic diagram of the surface potential distribution at the interface of CdZnTe / HgCdTe material grown by molecular beam epitaxy after 15 minutes of oxidation.

[0060] Figure 4 Schematic diagram of the surface potential distribution at the interface of CdZnTe / HgCdTe material grown by molecular beam epitaxy after 12 hours of oxidation.

[0061] Figure 5 Schematic diagram of the differential capacitance distribution at the interface of CdZnTe / HgCdTe material grown by liquid phase epitaxy.

[0062] Figure 6 This is a schematic diagram of the differential capacitance distribution at the interface of CdZnTe / HgCdTe material grown by molecular beam epitaxy.

[0063] The figure shows:

[0064] 1 substrate 2 Epitaxial HgCdTe thin film 3External AC bias 4-probe cantilever 5 Scanning capacitance microscopy measurement circuit 6 Epitaxial growth direction 7. Atmosphere operation box DETAILED DESCRIPTION

[0065] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0066] According to the present invention, a method for analyzing and evaluating the interface quality of an easily oxidized semiconductor epitaxial film is provided. Figure 1For example, using an operating atmosphere of high-purity inert gas, first screen the material in the appropriate oxidation state by measuring the surface potential, and then combine it with differential capacitance measurement to obtain relevant information about the material interface by performing difference or differential processing on the measurement results.

[0067] Specifically, Figure 2 For example, the steps for obtaining information about its interface quality include:

[0068] Step S1: prepare an atmosphere operation box and a low oxygen atmosphere;

[0069] Specifically, the equipment includes an atmosphere operating box that integrates oxygen monitoring equipment, a cleavage platform, cleavage tools, and a high-purity inert gas interface. The operating box is made of 8mm thick transparent acrylic sheet and is equipped with a glove interface and a gas circulation system.

[0070] Taking the spatial distribution of carriers in CdZnTe / HgCdTe as an example, the growth direction consists of a substrate and a HgCdTe layer. The epitaxial layer is only about ten microns thick, while the substrate is several hundred microns thick. The sample material is placed in an operating chamber and a high-purity inert gas (such as nitrogen or argon) is introduced. The oxygen monitoring device is monitored and the oxygen level is stopped at 2 to ensure that the sample is pre-treated in a low-oxygen environment.

[0071] The low oxygen environment, ie, the low oxygen atmosphere, has an oxygen content of less than 2% to ensure that the material will not be oxidized relatively quickly.

[0072] Step S2, sample preparation includes two steps: sample pretreatment and oxidation treatment.

[0073] Pretreatment step: pretreating the sample in a low-oxygen atmosphere to obtain nanoscale cross-sections;

[0074] Specifically, the material is processed in a low-oxygen environment: the sample is cleaved in an inert atmosphere, and nanoscale flat cross-sections are prepared along the material's natural cleavage planes, resulting in a nanoscale flat surface with a root mean square roughness of less than 0.2nm. A sufficiently smooth cleavage surface is essential for subsequent electrical measurements.

[0075] Oxidation step, controlling oxidation time to obtain dielectric layers in different states;

[0076] Specifically, oxygen is introduced immediately after cleavage and timing is started to calibrate the oxidation time of the material, and oxide dielectric layers of different thicknesses are formed by regulating the oxidation time.

[0077] During the oxidation process, the oxygen content in the atmosphere is kept constant within a specified time, and the constant value is preferably 21%. This method is particularly suitable for semiconductor materials and devices that are easily oxidized to prevent excessive oxidation of the cross section.

[0078] In more preferred embodiments, the CdZnTe / HgCdTe material is mechanically cleaved along the

[110] crystal direction in a nitrogen operating box to obtain an atomically flat cross-section to be tested. After successful cleavage, the cross-section of the sample to be tested is placed vertically with the cross-section facing upward, and the bottom is glued to an iron sheet with conductive silver glue to form a common electrode. The oxygen content in the box is less than 2%. After the electrode is made, the nitrogen gas is turned off, allowing air to contact the prepared sample and starting the timer to calibrate the oxidation time of the material. After different oxidation times, a KPFM test is performed on it to evaluate the oxidation state of the material. A scanning capacitance test is also performed on the sample with an oxidation time of 12 hours.

[0079] Step S3, measuring the potential of the material surface at different oxidation times under an inert atmosphere;

[0080] Specifically, the surface potential of samples subjected to different oxidation times is measured to determine the oxidation state. Surface potential measurements are performed on oxidized samples in an inert atmosphere to screen for samples with an appropriate oxidation state. The potential measurement results are then processed and analyzed to determine information about the material's oxide layer.

[0081] Specifically, the controlling and measuring of the oxidation degree of the material cross section includes using a scanning probe microscope.

[0082] In more preferred embodiments, the surface potential test uses an Rtesp probe with a drive amplitude of 8000mV. The potential distribution curve of HgCdTe is obtained as follows: Figure 3 and Figure 4 As shown in the figure. For samples with different oxidation times, the potential difference across the interface—that is, the potential difference between the substrate and the epitaxial film—is calculated and compared. For epitaxial HgCdTe materials, when the potential difference is less than 5mV or a smaller set value, the surface oxide layer thickness is approximately 1 to 5nm. This oxide layer thickness can be used for scanning capacitance measurement.

[0083] The surface potential measurement results of HgCdTe materials grown by molecular beam epitaxy (MBE) were analyzed to screen samples with appropriate oxidation states. Figure 3For example, in the sample oxidized for 15 minutes, the potential difference between the substrate and the epitaxial HgCdTe film is 20mV (the substrate potential is lower), and the potential distribution is uniform. The potential curves of the two regions are parallel, indicating that the electron concentration at the interface is uniformly distributed and there is no obvious charge accumulation or depletion. The potential difference of the sample oxidized for 12 hours dropped to 5mV, and the distribution showed a gradient: the potential on the substrate side increased from -1.5mV to about 1.5mV as the distance from the interface increased (the hole concentration gradient decreased, and the p-type characteristics weakened), and the potential on the epitaxial side decreased from 3.5mV to about 1mV as the distance increased (the electron concentration gradient decreased, and the n-type characteristics weakened). This change in potential indicates the state of the oxide layer on the surface of the material, making it more suitable for subsequent scanning capacitance measurements.

[0084] Step S4: Based on the material properties and the potential measurement results, select the sample material after oxidation for a suitable time, measure the electrical distribution at the interface of the test sample using the electrical measurement mode of a scanning probe microscope under an inert atmosphere, and perform differential processing and analysis on the measurement results.

[0085] Specifically, the electrical measurement modes include conductive atomic force microscopy, Kelvin probe force microscopy, and scanning capacitance microscopy. Scanning capacitance microscopy (SCM) testing is performed on selected, oxidized sample materials, focusing on analyzing the differential capacitance distribution at the substrate-epitaxial interface. Interfacial electrical properties are analyzed through difference calculation and differential processing.

[0086] Scanning capacitance microscopy measurements are also performed in a high-purity inert atmosphere. The electrical results are then differentially processed to determine and analyze the film quality at the interface of the material.

[0087] In more preferred embodiments, the scanning capacitance test uses a diamond conductive coated Si probe, and the light spot in the scanning capacitance microscope system is irradiated on the cantilever so that the value of its reflected signal is greater than 3.0. The differential capacitance of the interface area between the film and the substrate is measured using a scanning capacitance microscope with an AC bias of 1V. The scanning capacitance data of the carrier distribution characteristics of the sample test area is recorded through a loop and differential processing is performed. The results are as follows: Figure 5 and Figure 6 If the differential capacitance signal on both sides of the interface is evenly distributed without obvious signal peaks, it indicates that the film has good quality growth and no obvious carrier recombination defects. If the differential capacitance signal has obvious signal peaks, there may be defects or uneven composition within the film.

[0088] by Figure 5For example, the analysis of the differential capacitance signal of the liquid phase epitaxy (LPE) sample shows that a strong p-type signal (150mV, width 0.5μm) appears on the interface substrate side, while the signal value away from the interface area is stable at 25mV. This abnormal signal directly corresponds to a significant decrease in the hole concentration at the interface, suggesting that the acceptor state near the interface is reduced, resulting in a decrease in the hole concentration. On the epitaxial layer side, the differential capacitance signal shows an n-type conductivity signal, and the signal is stable at -100mV, reflecting that the electron concentration distribution in the epitaxial layer is highly uniform, without local concentration gradients or abnormal fluctuations.

[0089] by Figure 6 For example, the substrate side of the MBE-grown sample has no capacitance signal peak and exhibits p-type conductivity. However, the capacitance signal increases from 10mV to 40mV as the distance from the interface increases, indicating that the hole concentration on the substrate side decreases significantly as the distance from the interface increases (the concentration gradient decreases by about 75%). A strong signal of -80mV with a width of 0.8μm appears near the interface of the epitaxial film side. The signal value in the area away from the interface is -60mV, and the signal is stable near this value. This indicates that the electron concentration in the epitaxial layer near the interface is lower than that in the area away from the interface.

[0090] By combining surface potential measurements, materials with appropriate oxidation degrees are screened for scanning capacitance testing. These two electrical evaluations have high spatial resolution and high sensitivity at the nanoscale, and can provide spatial electrical information between the substrate and the epitaxial semiconductor film. This is of great significance for evaluating and analyzing the quality of the epitaxial interface of semiconductor materials, and predicting and optimizing the device performance of related materials.

[0091] According to the present invention, a system for analyzing and evaluating the interface quality of an easily oxidized semiconductor epitaxial film is provided, which comprises an atmosphere operation box, a substrate, a scanning capacitance microscopy measurement circuit and a probe cantilever.

[0092] The substrate is located in an atmosphere operating box and is connected to the probe cantilever via a scanning capacitance microscopy measurement circuit;

[0093] Maintain a low oxygen atmosphere in the atmosphere operation box.

[0094] The atmosphere operation box integrates oxygen monitoring equipment, a cleavage platform, a cleavage tool, a high-purity inert gas interface, a glove interface and a gas circulation system.

[0095] In more preferred embodiments, a sample is prepared in an atmosphere operation box, and potential measurement is performed to obtain a potential measurement result;

[0096] According to the material properties of the sample and the potential measurement results, the sample is subjected to a scanning capacitance test in a low-oxygen atmosphere, and the measurement results are processed and analyzed.

[0097] The low oxygen atmosphere has an oxygen content of less than 2%.

[0098] The preparation of the low oxygen atmosphere is to place the sample material in an operating box, introduce high-purity inert gas, observe the value of the oxygen monitoring device, and stop when the monitoring value reaches 2.

[0099] The scanning capacitance test selects a sample oxidized for a suitable time, performs the scanning capacitance test in a low-oxygen atmosphere using an electrical measurement mode of a scanning probe microscope to measure the differential capacitance distribution at the sample interface, and processes and analyzes the measurement results.

[0100] In more preferred embodiments, the electrical measurement mode includes a conductive atomic force microscopy mode, a Kelvin probe force microscopy mode, and a scanning capacitance microscopy mode;

[0101] The interface is the interface region between the substrate and the epitaxial layer.

[0102] The processing and analysis is to analyze the electrical characteristics through difference calculation and differential processing. If the value of the differential capacitance signal is evenly distributed without obvious signal peaks, it indicates that the film quality is good. If the value of the differential capacitance signal has obvious signal peaks, the film quality is poor.

[0103] The scanning capacitance test uses a Si probe with a diamond conductive coating, and irradiates the light spot in the scanning capacitance microscope system on the probe cantilever. The value of the reflected signal is greater than 3.0, and the AC bias voltage is 1V.

[0104] The measurement result is the value of the scanning capacitance signal of the sample carrier distribution characteristic recorded by the loop.

[0105] In more preferred embodiments, the sample preparation includes a pretreatment operation and an oxidation operation.

[0106] The pretreatment operation is to cleave the sample along the natural cleavage plane in a low-oxygen atmosphere to form a nanometer-level flat surface and place it vertically upward, with the bottom fixed on the iron sheet through a conductive material to form a common electrode.

[0107] The nanoscale flat surface is a cross-section with a root mean square roughness of less than 0.2 nm.

[0108] The oxidation operation is to introduce oxygen and calibrate it, start timing, keep the oxygen content in the atmosphere operation box at a constant value within a specified time, and perform KPFM testing.

[0109] In more preferred embodiments, the potential measurement is to measure the surface potential of samples after different oxidation times, determine the oxidation state using a scanning probe microscope, and obtain and process the potential measurement results.

[0110] The potential measurement results include the substrate side potential and the epitaxial side potential, and the potential difference between the substrate and the epitaxial film is obtained by processing.

[0111] The surface potential test uses an Rtesp probe with a drive amplitude of 8000 mV.

[0112] The process includes calculating and comparing the potential difference between the substrate and the epitaxial film for samples with different oxidation times, and performing scanning capacitance measurement when the potential difference is smaller than a set value.

[0113] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0114] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A method for analyzing and evaluating the interface quality of an easily oxidizable semiconductor epitaxial film, characterized in that: include: Step S1, making an atmosphere operation box and preparing a low oxygen atmosphere; Step S2, preparing a sample in an atmosphere operation box; Step S3, measuring the potential of the sample surface in a low-oxygen atmosphere to obtain a potential measurement result; Step S4: Based on the material properties of the sample and the potential measurement results, a scanning capacitance test is performed on the sample in a low-oxygen atmosphere, and the measurement results are processed and analyzed.

2. The method for analyzing and evaluating the interface quality of an easily oxidizable semiconductor epitaxial film according to claim 1, wherein: The atmosphere operation box includes oxygen monitoring equipment, a cleavage platform, a cleavage tool, a high-purity inert gas interface, a glove interface and a gas circulation system; The low oxygen atmosphere has an oxygen content of less than 2%; In step S1, the sample material is placed in an operating box, high-purity inert gas is introduced, and the value of the oxygen monitoring device is observed, and the monitoring value is stopped when it reaches 2; In step S4, a sample oxidized for a suitable time is selected, and a scanning capacitance test is performed in a low-oxygen atmosphere using an electrical measurement mode of a scanning probe microscope to measure the differential capacitance distribution at the sample interface, and the measurement results are processed and analyzed.

3. The method for analyzing and evaluating the interface quality of an easily oxidizable semiconductor epitaxial film according to claim 2, wherein: The electrical measurement modes include conductive atomic force microscopy mode, Kelvin probe force microscopy mode and scanning capacitance microscopy mode; The interface is the interface region between the substrate and the epitaxial layer; The processing and analysis is to analyze the electrical characteristics through difference calculation and differential processing. If the value of the differential capacitance signal is evenly distributed without obvious signal peaks, it indicates that the film quality is good. If the value of the differential capacitance signal has obvious signal peaks, the film quality is poor. The scanning capacitance test uses a diamond conductive coated Si probe, and the light spot in the scanning capacitance microscope system is irradiated on the cantilever. The value of the reflected signal is greater than 3.0, and the AC bias voltage is 1V. The measurement result is the value of the scanning capacitance signal of the sample carrier distribution characteristic recorded by the loop.

4. The method for analyzing and evaluating the interface quality of an easily oxidizable semiconductor epitaxial film according to claim 1, wherein: Said step S2 includes a pretreatment step and an oxidation step; In the pretreatment step, the sample is cleaved along the natural cleavage plane in a low-oxygen atmosphere to form a nanometer-level flat surface and placed vertically upward, with the bottom fixed on the iron sheet by a conductive material to form a common electrode; The nanoscale flat surface is a cross-section with a root mean square roughness of less than 0.2 nm; During the oxidation step, oxygen is introduced and calibrated, and timing is started to maintain the oxygen content in the atmosphere operation box at a constant value within a specified time, and a KPFM test is performed.

5. The method for analyzing and evaluating the interface quality of an easily oxidizable semiconductor epitaxial film according to claim 1, wherein: In step S3, the surface potential of the samples after different oxidation times is measured, the oxidation state is determined using a scanning probe microscope, and the potential measurement results are obtained and processed; The potential measurement results include the substrate side potential and the epitaxial side potential, and the potential difference between the substrate and the epitaxial film is obtained by processing; The surface potential test uses an Rtesp probe with a drive amplitude of 8000mV; The process includes calculating and comparing the potential difference between the substrate and the epitaxial film for samples with different oxidation times. When the potential difference is less than a set value, step S4 is executed.

6. A system for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial films, characterized in that: include: Atmosphere operating box, substrate, scanning capacitance microscopy measurement circuit and probe cantilever; The substrate is located in an atmosphere operating box and is connected to the probe cantilever via a scanning capacitance microscopy measurement circuit; Maintain a low oxygen atmosphere in the atmosphere operation box; The atmosphere operation box integrates oxygen monitoring equipment, a cleavage platform, a cleavage tool, a high-purity inert gas interface, a glove interface and a gas circulation system.

7. The system for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial thin films according to claim 6, wherein: Prepare a sample in an atmosphere operation box, perform potential measurement, and obtain potential measurement results; According to the material properties of the sample and the potential measurement results, the sample is subjected to a scanning capacitance test in a low-oxygen atmosphere, and the measurement results are processed and analyzed. The low oxygen atmosphere has an oxygen content of less than 2%; The preparation of the low oxygen atmosphere is to place the sample material in an operating box, introduce high-purity inert gas, observe the value of the oxygen monitoring device, and stop when the monitoring value reaches 2; The scanning capacitance test selects a sample oxidized for a suitable time, performs the scanning capacitance test in a low-oxygen atmosphere using an electrical measurement mode of a scanning probe microscope to measure the differential capacitance distribution at the sample interface, and processes and analyzes the measurement results.

8. The system for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial thin films according to claim 7, wherein: The electrical measurement modes include conductive atomic force microscopy mode, Kelvin probe force microscopy mode and scanning capacitance microscopy mode; The interface is the interface region between the substrate and the epitaxial layer; The processing and analysis is to analyze the electrical characteristics through difference calculation and differential processing. If the value of the differential capacitance signal is evenly distributed without obvious signal peaks, it indicates that the film quality is good. If the value of the differential capacitance signal has obvious signal peaks, the film quality is poor. The scanning capacitance test uses a diamond conductive coated Si probe, and the light spot in the scanning capacitance microscope system is irradiated on the probe cantilever. The value of the reflected signal is greater than 3.0, and the AC bias voltage is 1V. The measurement result is the value of the scanning capacitance signal of the sample carrier distribution characteristic recorded by the loop.

9. The system for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial thin films according to claim 6, wherein: The sample preparation includes a pretreatment operation and an oxidation operation; The pretreatment operation is to cleave the sample along the natural cleavage plane in a low-oxygen atmosphere to form a nanometer-level flat surface and place it vertically upward, with the bottom fixed on the iron sheet by a conductive material to form a common electrode; The nanoscale flat surface is a cross-section with a root mean square roughness of less than 0.2 nm; The oxidation operation is to introduce oxygen and calibrate it, start timing, keep the oxygen content in the atmosphere operation box at a constant value within a specified time, and perform KPFM testing.

10. The system for analyzing and evaluating the interface quality of easily oxidized semiconductor epitaxial thin films according to claim 6, wherein: The potential measurement is to measure the surface potential of the samples after different oxidation times, use a scanning probe microscope to determine the oxidation state, obtain the potential measurement results and process them; The potential measurement results include the substrate side potential and the epitaxial side potential, and the potential difference between the substrate and the epitaxial film is obtained by processing; The surface potential test uses an Rtesp probe with a drive amplitude of 8000mV; The process includes calculating and comparing the potential difference between the substrate and the epitaxial film for samples with different oxidation times, and performing scanning capacitance measurement when the potential difference is smaller than a set value.

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