CVD online in-situ characterization system and method based on absorption spectrum

Abstract

A CVD online in-situ characterization system and method based on an absorption spectrum, which system and method belong to the technical field of semiconductor production devices. The CVD online in-situ characterization system comprises an absorption-spectrum detection apparatus, a spectrum movement and light-path calibration apparatus, and a tubular CVD device. By means of improving an existing tubular CVD device and in conjunction with the proposed environment compensation method, the accurate inspection of a chemical vapor deposition process in a high-temperature and low-pressure environment is realized; by means of real-time inspection, the pattern of a sample or a reaction system changing over time can be obtained; and in view of changes in the temperature and pressure of the system, the pattern of the sample or the reaction system changing over temperature and pressure is further obtained, such that optimal deposition conditions can be determined. In addition, by means of automatic light-path calibration, the system can inspect the deposition situation of the sample at any position in a quartz tube during the chemical vapor deposition process, such that an accurate growth window of the sample can be quickly determined.

Description

A CVD online in-situ characterization system and method based on absorption spectroscopy Technical Field

[0001] The invention relates to a CVD online in-situ characterization system and method based on absorption spectroscopy, belonging to the technical field of semiconductor production equipment. Background Art

[0002] Deposition is a crucial technique in semiconductor processing and manufacturing, and the equipment involved is collectively referred to as thin film deposition equipment. Common thin film deposition processes are categorized as physical vapor deposition (PVD) and chemical vapor deposition (CVD). Chemical vapor deposition (CVD) involves the interaction of reactants, or between reactants and a substrate material, under specific temperature and pressure conditions to produce the target product on the substrate. Typically, the reactants in CVD are gaseous, while the products are solid. For example, the growth of carbon nanotubes on a quartz substrate requires the introduction of CH4 gas as a reactant, while the products are solid carbon nanotubes. CVD, due to its advantages such as simple preparation, large growth area, and ease of transfer, has gradually become a key method in atomic-scale fabrication. This has led to the development of atomic layer deposition (ALD), which has been widely used in the preparation of various material systems, including graphene, carbon nanotubes, and disulfides. CVD equipment, represented by tube furnaces, is one of the core equipment for atomic-scale manufacturing.

[0003] Considering that chemical vapor deposition (CVD) and atomic layer deposition (ALD) are usually carried out at a certain temperature and under certain vacuum conditions, existing chemical vapor deposition (CVD) equipment cannot detect the thin film deposition situation in real time during the thin film deposition process. Usually, after the deposition is completed, the deposited sample is removed from the CVD equipment and then tested using various methods. This method of transferring the sample for testing is collectively referred to as non-in-situ characterization technology. However, for the atomic layer deposition (ALD) process, such as the deposition process of materials such as graphene and carbon nanotubes, it is necessary to perform in-situ detection of the thin film growth process in order to understand the structural changes and reaction mechanisms of the substances during the reaction process, and to study the microstructure of the intermediates and products in the reaction process. However, existing CVD equipment, such as tubular furnaces, cannot achieve in-situ detection.

[0004] Existing in-situ characterization technologies mainly serve electrochemical research. Most of their reaction devices are equipped with reaction cells with a small overall area, and cannot be directly applied to CVD equipment such as chemical vapor deposition, which has a larger overall experimental device. In addition, the high temperature and low pressure environment associated with chemical vapor deposition will also lead to errors in the obtained in-situ characterization results. Summary of the Invention

[0005] In order to solve the problem that existing CVD equipment cannot achieve in-situ detection, the present invention provides a CVD online in-situ characterization system and method based on absorption spectroscopy. By designing a system that can perform real-time in-situ detection of deposited samples during the vapor deposition process, and taking into account the influence of deposition parameters on the detection results and making corresponding compensation, online in-situ detection of the vapor deposition process is achieved, which makes it possible to study the microstructure of intermediates and products in the reaction process and determine the optimal deposition conditions.

[0006] The first purpose of the present application is to provide an online in-situ characterization system for CVD based on absorption spectroscopy, the system comprising: an absorption spectrum detection device, a spectrum movement and optical path calibration device and a tubular CVD device; and the online in-situ characterization of the deposited sample is achieved through the absorption spectrum detection device.

[0007] The absorption spectrum detection device includes a light source, a light source emitting device, a light source receiving device, and a spectrometer connected to the light source receiving device;

[0008] The spectrum movement and optical path calibration device includes two moving rails, on which the light source emitting device and the light source receiving device are respectively installed; the light source emitting device and the light source receiving device are moved by the moving rails, thereby realizing online in-situ characterization of samples at any position in the quartz tube.

[0009] The tubular CVD equipment includes a furnace, a quartz tube and a quartz boat in the quartz tube for carrying deposited samples; in order to enable the light emitted by the light source emitting device to pass through the furnace, and in order to realize online in-situ characterization of samples at any position in the quartz tube, two symmetrical light-through grooves parallel to the quartz tube are opened on the furnace of the present application, and the two light-through grooves are symmetrical with the axial center line of the quartz tube. The two moving tracks in the spectrum movement and optical path calibration device are respectively located at the positions corresponding to the two light-through grooves on the outside of the furnace, so that the light source emitting device and the light source receiving device can move in a straight line along the axial direction of the quartz tube to realize in-situ detection of samples at any position in the quartz tube; the light emitted by the light source emitting device passes through the light-through groove, the quartz tube and the deposited sample therein to reach the light source receiving device, and then the spectrometer performs spectral analysis according to the received light source to realize in-situ detection of the deposited sample; the width of the light-through groove is set based on the ability to allow the light emitted by the light source emitting device and the light received by the light source receiving device to pass completely.

[0010] Optionally, the spectral movement and optical path calibration device also includes four stepper motors and is equipped with a four-axis optical path automatic calibration system. The four stepper motors are respectively recorded as a first transverse stepper motor, a first longitudinal stepper motor, a second transverse stepper motor and a second longitudinal stepper motor; wherein, the first transverse stepper motor and the first longitudinal stepper motor realize the positioning of the light source emitting device in the horizontal plane through a band-pass ball screw and a movable rail, and the second transverse stepper motor and the second longitudinal stepper motor are used to control the rotation of the light source emitting device in the horizontal plane and the vertical plane.

[0011] Optionally, the four-axis optical path automatic calibration system uses a single-chip microcomputer or PLC controller to control the stepper motors. By setting the PWM wave of each motor, its speed can be controlled. By comparing the returned light intensity, the optical path can be fine-tuned to maximize the received light intensity, facilitating subsequent spectral analysis.

[0012] Optionally, the light source is a white light source with a continuous spectrum and a wavelength covering at least 200-1050nm, wherein the luminous flux in the ultraviolet band within the wavelength range of 250nm-400nm is greater than 10mW / mm 2 ·sr·nm; and the light source has strong collimation, and the light spot can be focused into a circle with a diameter of 1mm within a distance of 0.5m.

[0013] The second object of the present application is to provide a CVD online in-situ characterization method based on absorption spectroscopy, which is implemented based on the above system and includes:

[0014] Step 1: optical path calibration, using a spectrum shift and optical path calibration device to align the light source emitting device and the light source receiving device in the absorption spectrum detection device;

[0015] Step 2, using an absorption spectrum detection device to obtain the absorption spectrum of the deposited sample during the deposition process;

[0016] Step 3: Perform in-situ detection on the deposited sample based on the acquired absorption spectrum of the deposited sample.

[0017] Optionally, step 2 includes:

[0018] Step 2.1, using an absorption spectrum detection device to obtain red light compensation spectra at different interval temperatures in a tubular CVD device without placing a sample;

[0019] Step 2.2, obtaining the real-time absorption spectrum during the deposition process;

[0020] In step 2.3, the final spectrum of the deposited sample is obtained by subtracting the red light compensation spectrum at the corresponding temperature from the real-time absorption spectrum.

[0021] Optionally, the step 2.1 includes:

[0022] Without placing any sample, at room temperature, allow the light path to pass through the quartz tube and quartz boat to reach the light source receiving device to obtain a spectrum, which is recorded as the initial spectrum;

[0023] Increase the temperature gradually, starting from 100℃ Take a spectrum in degrees Celsius and subtract it from the initial spectrum to obtain the red light compensation spectrum under different temperature gradients.

[0024] Optionally, step 1 includes: using the first transverse stepper motor and the first longitudinal stepper motor to search for the position of the light source receiving device by traversal, and then using the second transverse stepper motor and the second longitudinal stepper motor to maximize the intensity of the incident light by fine-tuning the angle.

[0025] A third object of the present application is to provide a method for determining a growth window of a deposited sample, the method being implemented based on the above system and comprising:

[0026] Step S1, optical path calibration, using a spectrum shift and optical path calibration device to align the optical paths of a light source emitting device and a light source receiving device in an absorption spectrum detection device;

[0027] Step S2, controlling the light source emitting device and the light source receiving device to move along the moving track, and obtaining the absorption spectrum corresponding to the deposited sample at each position during the deposition process in real time;

[0028] Step S3, determining the growth window of the deposited sample according to the absorption spectrum corresponding to the deposited sample at each position during the deposition process.

[0029] Optionally, step S3 includes:

[0030] The material growth at different positions is analyzed based on the absorption spectra corresponding to the deposited samples at various positions during the deposition process;

[0031] The position where the material grows best is used as the growth window of the deposited sample.

[0032] The beneficial effects of the present invention are:

[0033] By improving existing tubular CVD equipment and combining it with the proposed environmental compensation method, accurate detection of chemical vapor deposition processes in high-temperature, low-pressure environments is achieved. Furthermore, because this application can achieve real-time detection, it is possible to obtain patterns of sample or reaction system changes over time. Combined with changes in system temperature and pressure, this can further reveal patterns of sample or reaction system changes with environmental factors such as temperature and pressure, thereby determining optimal deposition conditions. Furthermore, through automatic optical path calibration, the system can detect the deposition of samples at any location within the quartz tube during the chemical vapor deposition process, thereby quickly determining the exact growth window for the sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] FIG1 is a schematic diagram of a CVD online in-situ characterization system based on absorption spectroscopy provided by the present invention;

[0036] FIG2 is a top view of a furnace in a CVD online in-situ characterization system based on absorption spectroscopy provided by the present invention;

[0037] Among them, 1. furnace, 2. quartz tube, 3. quartz boat, 4. deposited sample, 5. light slot, 6. light source, 7. light source emitting device, 8. light source receiving device, 9. spectrometer, 10. track, 11. stepper motor.

[0038] FIG3 is a three-dimensional schematic diagram of a four-axis optical path calibration system;

[0039] FIG4 is a planar schematic diagram of a four-axis optical path calibration system; wherein 1101 is a first transverse stepping motor, 1102 is a first longitudinal stepping motor, 1103 is a second longitudinal stepping motor, and 1104 is a second transverse stepping motor.

[0040] Figure 5 is a spectrum diagram of a xenon lamp light source.

[0041] FIG6 is a spectrum diagram of the improved white light source used in this application.

[0042] FIG7 is a schematic diagram of the position of the light-transmitting slots on the furnace in the CVD tube furnace based on absorption spectroscopy provided by the present invention.

[0043] FIG8 is an online absorption spectrum obtained during a low growth rate experiment using the CVD online in-situ characterization system based on absorption spectroscopy provided by the present application.

[0044] Figure 9 is a photo of the samples from the low growth rate experiment.

[0045] FIG10 is an online absorption spectrum obtained during a high growth rate experiment using the CVD online in-situ characterization system based on absorption spectroscopy provided by the present application.

[0046] Figure 11 is a photo of the samples from the high growth rate experiment.

[0047] FIG12 is a Raman spectrum of the high growth rate experiment.

[0048] FIG13 is an electron microscope (SEM) image of the high growth rate experiment. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0050] Example 1:

[0051] The present embodiment provides an online in-situ characterization system for CVD based on absorption spectroscopy. As shown in FIG1 , the online in-situ characterization system for CVD based on absorption spectroscopy includes: an absorption spectrum detection device, a spectrum shifting and optical path calibration device, and a tubular CVD device; wherein the absorption spectrum detection device includes a light source 6, a light source emitting device 7, a light source receiving device 8, and a spectrometer 9 connected to the light source receiving device 8; the spectrum shifting and optical path calibration device includes two moving rails 10 and corresponding stepping motors 11, and the light source emitting device 7 and the light source receiving device 8 are respectively installed on the two moving rails 10; the tubular CVD device includes a furnace 1, a quartz tube 2, and a quartz tube. 2 is used to carry the deposited sample in a quartz boat 3; two symmetrical light-through slots 5 parallel to the quartz tube are opened on the furnace 1, as shown in Figure 2, the two light-through slots 5 take the axial center line of the quartz tube as the symmetry axis, and the two moving tracks 10 in the spectrum moving device are respectively located at the positions corresponding to the two light-through slots 5 on the outside of the furnace 1, so that the light source emitting device 7 and the light source receiving device 8 can move in a straight line along the axial direction of the quartz tube 2; the light emitted by the light source emitting device 7 passes through the light-through slots 5, the quartz tube 2 and the deposited sample 4 therein to reach the light source receiving device 8, and then the spectrometer 9 performs spectral analysis according to the received light source to realize in-situ detection of the deposited sample 4.

[0052] The length of the light-passing slot 5 can be determined according to actual conditions, and the width is set so as to allow the light emitted by the light source emitting device 7 and the light received by the light source receiving device 8 to pass through completely.

[0053] It should be noted that the tubular CVD equipment includes other conventional components in addition to the furnace, quartz tube, and quartz boat inside the quartz tube for carrying deposited samples. This application does not improve other components, so other conventional components are not described.

[0054] To ensure that the light emitted by the light source emitting device 7 can be accurately received by the light source receiving device 8, the present application has designed a four-axis optical path calibration system, which uses four stepper motors 11 to achieve optical path alignment between the light source emitting device 7 and the light source receiving device 8. Specifically, as shown in Figures 3 and 4, the first horizontal stepper motor 1101 and the first vertical stepper motor 1102 are used for coarse adjustment, and the second horizontal stepper motor 1104 and the second vertical stepper motor 1103 are used for fine adjustment. The first horizontal stepper motor 1101 and the first vertical stepper motor 1102 are positioned in the horizontal plane by a bandpass ball screw and a slide rail. The second horizontal stepper motor 1104 and the second vertical stepper motor 1103 are used to control the rotation of the light source emitting device 7 in the horizontal and vertical planes. The combination of the four motors can achieve light source calibration, and the control of the four stepper motors is achieved by a single-chip microcomputer or PLC controller. The speed can be controlled by setting the PWM wave of each motor. By comparing the returned light intensity, the optical path can be fine-tuned to maximize the received light intensity, facilitating subsequent spectral analysis.

[0055] Considering the high-temperature, low-pressure environment within the quartz tube during the chemical vapor deposition process (for example, the furnace chamber appears red under high-temperature conditions, which can affect the light source signal), the light source selection process for the aforementioned absorption spectroscopy-based CVD online in-situ characterization system is as follows: First, a xenon lamp was selected as the first white light source. Its advantages include high brightness and a wide spectral range, with a wavelength range of 200-2500 nm, covering the ultraviolet, visible, and infrared spectra. When powered on, a 150 W high-voltage, short-arc spherical xenon lamp installed within the xenon lamp source chamber generates an arc discharge under high-frequency, high-voltage excitation. This small point of light emits a strong, stable, continuous spectrum when ignited, with a visible light color very similar to sunlight. The white light is transmitted to the outside through an optical fiber at the end. Actual testing revealed that the signal from this white light source is weak in the ultraviolet band, particularly in the 200-300 nm range. The specific spectral signal is shown in Figure 5, which plots the number of photons collected for different wavelengths. A higher number of collected photons indicates a higher light intensity.

[0056] However, the ultraviolet band plays a relatively important role in the detection process, so this application replaces a laser-induced white light source with a stronger signal in the ultraviolet band to meet the experimental needs. Compared with the xenon lamp light source, the laser-induced white light source has a stronger signal, especially in the ultraviolet band. And in order to further reduce the loss in the ultraviolet band, the light source needs to be passed through with a purge gas, otherwise the oxygen in the atmosphere will form ozone, which will weaken the light output in the 220-289 nm band. Nitrogen is selected as the purge gas, and a steel cylinder is used for gas supply. The pressure reducing valve and the ball valve are installed in the air inlet line in turn, and finally the nitrogen can be introduced into the lamp house through a 4 mm quick-insert tube for purge. The specific spectral signal of the improved light source is shown in Figure 6. Compared with Figure 5, it can be seen that the signal of the improved spectral signal at 200 nm-300 nm has been enhanced.

[0057] The spectrometer 9 must meet the measurement wavelength range of 200 nm to 1050 nm and can be a StellarNet Blue-Wave UVNb spectrometer. This model of spectrometer measures wavelengths within the range of 200 nm to 1050 nm and also has the advantages of being small in size and fast in response. It can quickly read real-time spectra when used with the spectrum analysis software SpectraWiz. After receiving the incident white light, the light source receiving device 8 transmits the light to the spectrometer via optical fiber. After data analysis and processing, spectral information can be obtained. Other spectrometers may include the HORIBA iHR320, PG2000-pro, FLEX+ UV-Vis-NIR Spectrometer, and other models.

[0058] It should be noted that the light source in the CVD online in-situ characterization system based on absorption spectroscopy provided in this application may be, in addition to the improved laser-induced white light source selected above, other light sources that meet the following conditions:

[0059] 1) Continuous spectrum, wavelength covering 200-2000nm;

[0060] 2) The overall light intensity is strong enough, especially in the ultraviolet band (200nm-400nm), the luminous flux is greater than 10mW / mm 2 ·sr·nm;

[0061] 3) Strong collimation, the light spot can be focused into a circle with a diameter of 1mm within a distance of 0.5m.

[0062] For example, EQ-99-FC-S LDLS, EQ-77X-QZ-S LDLS, HPX-2000 xenon lamp light source and HGILX300 xenon lamp light source.

[0063] Example 2

[0064] This embodiment provides an online in-situ characterization method for CVD based on absorption spectroscopy. The method is implemented based on the online in-situ characterization system for CVD based on absorption spectroscopy provided in Example 1. As shown in FIG7 , which is a schematic diagram of a tubular furnace with a light-through slot 5 , the online in-situ characterization method for CVD based on absorption spectroscopy includes:

[0065] Step 1, optical path calibration;

[0066] During the optical path calibration process, the two motors at the bottom, namely the first horizontal stepper motor 1101 and the first vertical stepper motor 1102, search for the position of the light source receiving device 8, namely the spectrometer detector, by traversing, and then the two motors above, namely the second horizontal stepper motor 1104 and the second vertical stepper motor 1103, fine-tune the angle to maximize the intensity of the incident light, which is convenient for subsequent measurements.

[0067] The optical path calibration is achieved by the STM32 microcontroller. The speed of each motor can be controlled by setting the PWM wave. By comparing the light intensity received by the spectrometer detector, the optical path can be fine-tuned to maximize the received light intensity.

[0068] Step 2, obtaining a temperature gradient compensation spectrum;

[0069] Specifically include:

[0070] In step 2.1, no sample is placed, so that the light path passes through the quartz tube and the quartz boat to reach the light source receiving device 8, i.e., the spectrometer detector, and a spectrum is obtained, which is recorded as the initial spectrum.

[0071] Step 2.2, gradually increase the temperature to 900℃, starting from 100℃ and Take a spectrum and subtract it from the initial spectrum to obtain the red light compensation spectrum under different temperature gradients. An appropriate value can be selected according to actual conditions, such as 5°C, 10°C, 25°C, 50°C, etc. Subsequently, the spectrum at a certain temperature obtained in real time during the deposition process is subtracted from the corresponding red light compensation spectrum to obtain a more accurate absorption spectrum as the final spectrum.

[0072] When analyzing a substance based on absorption spectrum, the absorbance calculation formula is as follows:

[0073] Absorbance = log (incident light intensity / transmitted light intensity)

[0074] The incident light intensity is the intensity of the light emitted by the light source emitting device 7 , and the transmitted light intensity is the intensity of the light received by the light source receiving device 8 .

[0075] for example:

[0076] Before the sample is placed, light passes through the quartz boat and quartz tube. At room temperature (25°C), there is no red light. The intensity of the transmitted light at this time is recorded as L1.

[0077] After placing the sample, under the experimental environment, light passes through the quartz tube, quartz boat, and sample at a temperature of 800°C and with red light. The intensity of the transmitted light at this time is recorded as L2. Let the light intensity of the red light compensation spectrum corresponding to 800°C be recorded as L3. The absorbance (measured value) without compensation is , while the actual value (true value) , so the compensation value of the red light compensation spectrum corresponding to 800℃ is .

[0078] The above method is used to obtain the compensation value of the red light compensation spectrum corresponding to every 25 degrees Celsius starting from 100 degrees Celsius. .

[0079] In the subsequent deposition process, if the deposition temperature is set to 800°C, the obtained spectrum needs to subtract the compensation value of the red light compensation spectrum at 800°C. , and then analyze based on the final spectrum.

[0080] Step 3: Analyze the deposition status of the deposition process based on the final spectrum.

[0081] When the spectrometer 9 analyzes the deposition situation according to the final spectrum, it is implemented by using the existing spectrum analysis technology.

[0082] Since the light source emitting device 7 and the light source receiving device 8 of the present application are respectively installed on two movable rails 10, and the axial length of the light-passing groove opened on the furnace can enable the light source to reach any position in the quartz tube 2, the sample at any position in the quartz tube 2 can be detected in real time during the deposition process by moving the light source emitting device 7 and the light source receiving device 8 to obtain the sample deposition situation.

[0083] Existing in-situ techniques all focus on in-situ characterization of a single point. This application achieves movable in-situ characterization within a quartz tube by synchronously moving the white light source's light emitting device 7 and light receiving device 8. This innovation has significant implications for exploring the growth window of new materials.

[0084] In many CVD processes, after determining the temperature, pressure, carrier gas flow rate and other conditions, the material will grow at certain determined positions, which are usually called growth windows. In conventional experimental processes, it is necessary to conduct experiments repeatedly at different positions and perform offline characterization after the experiment. It may take several or even dozens of experiments to roughly determine its growth window. The process is cumbersome and takes a lot of time. The system and method of the present application can be moved arbitrarily during the experiment, and the growth window can be judged by characterizing the growth of materials at different positions, which makes it possible to quickly obtain better deposition effects.

[0085] Example 3

[0086] This embodiment provides a CVD online in-situ characterization method based on absorption spectroscopy. The method is implemented based on the CVD online in-situ characterization system based on absorption spectroscopy given in Example 1 and is described using a vertical single-walled carbon nanotube growth experiment as an example.

[0087] In traditional vertical single-walled carbon nanotube growth experiments, if you want to judge the experimental results, you need to take out the carbon nanotube sample after the experiment and observe it using a scanning electron microscope (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), etc., while the CVD online in-situ characterization system based on absorption spectroscopy provided by this application can perform real-time observation.

[0088] During the experiment, the online absorption spectrum of the entire experiment is obtained in real time.

[0089] Figure 8 shows an online absorption spectrum obtained during a low-growth-rate experiment (denoted as Experiment 1) using the absorption spectroscopy-based CVD online in-situ characterization system provided by this application. The maximum absorbance observed is around 0.135, indicating that the amount of growth is minimal. Figure 9 shows the experimental results of the low-growth-rate experiment, showing a light gray substance on the substrate surface, confirming that only a small amount of single-walled carbon nanotubes have grown on the substrate.

[0090] Figure 10 shows an online absorption spectrum obtained during a high-growth-rate experiment (denoted as Experiment 2) using the absorption-spectroscopy-based CVD online in-situ characterization system provided by this application. The maximum absorbance observed is around 1.5, indicating a significant amount of growth. Figure 11 shows the experimental results of the high-growth-rate experiment, showing the distinct presence of black material on the substrate surface. Combined with Raman spectroscopy (Figure 12) and SEM images (Figure 13), this confirms the presence of a significant number of single-walled carbon nanotubes (SWCNTs) grown on the substrate.

[0091] It should be noted that when the position of the in-situ characterization needs to be changed, the motor controlling the spectrometer detector at the top and the motor in the corresponding direction at the bottom move simultaneously for a specific distance, and then the optical path is automatically calibrated again before measurement.

[0092] According to Figures 8 and 10, the CVD online in-situ characterization system based on absorption spectroscopy provided in this application can determine the law of change of samples or reaction systems over time. Combined with the changes in system temperature and pressure over time, the law of change of samples or reaction systems with environmental changes such as temperature and pressure can be further obtained.

[0093] Some steps in the embodiments of the present invention may be implemented using software, and the corresponding software program may be stored in a readable storage medium, such as a CD or a hard disk.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A CVD online in-situ characterization system based on absorption spectroscopy, characterized in that: The system includes: an absorption spectrum detection device, a spectrum shift and optical path calibration device and a tubular CVD device; Among them, the absorption spectrum detection device includes a light source, a light source emitting device, a light source receiving device and a spectrometer connected to the light source receiving device; the spectrum movement and optical path calibration device includes two movable rails, and the light source emitting device and the light source receiving device are respectively installed on the two movable rails; the tubular CVD equipment includes a furnace, a quartz tube and a quartz boat in the quartz tube for carrying deposited samples; two symmetrical light-through grooves parallel to the quartz tube are opened on the furnace, and the two light-through grooves are symmetrical with the axial center line of the quartz tube as the axis of symmetry. The two movable rails in the spectrum movement and optical path calibration device are respectively located at the positions corresponding to the two light-through grooves on the outside of the furnace, so that the light source emitting device and the light source receiving device can move in a straight line along the axial direction of the quartz tube to realize in-situ detection of samples at any position in the quartz tube; the light emitted by the light source emitting device passes through the light-through groove, the quartz tube and the deposited sample therein to reach the light source receiving device, and then the spectrometer performs spectral analysis according to the received light source to realize in-situ detection of the deposited sample; The light source is a white light source with a continuous spectrum and a wavelength of at least 200-1050nm, wherein the ultraviolet band signal light flux within the wavelength range of 250nm-400nm is greater than 10mW / mm 2 ·sr·nm; When the spectrometer performs spectral analysis based on the received light source, the method for obtaining the absorption spectrum of the deposited sample includes: The red light compensation spectra at different interval temperatures in the tubular CVD device when no sample is placed are obtained using an absorption spectrum detection device; Obtain real-time absorption spectra during the deposition process; The final spectrum of the deposited sample was obtained by subtracting the red light compensation spectrum at the corresponding temperature from the real-time absorption spectrum.

2. The system according to claim 1, wherein: The spectral movement and optical path calibration device also includes four stepper motors and is equipped with a four-axis optical path automatic calibration system. The four stepper motors are respectively recorded as a first transverse stepper motor, a first longitudinal stepper motor, a second transverse stepper motor and a second longitudinal stepper motor; wherein, the first transverse stepper motor and the first longitudinal stepper motor realize the positioning of the light source emitting device in the horizontal plane through a band-pass ball screw and a movable track, and the second transverse stepper motor and the second longitudinal stepper motor are used to control the rotation of the light source emitting device in the horizontal plane and the vertical plane.

3. The system according to claim 2, characterized in that The four-axis optical path automatic calibration system adopts a single chip microcomputer or a PLC controller to realize the control of the stepping motor.

4. A CVD online in-situ characterization method based on absorption spectroscopy, characterized in that: The method is implemented based on the system according to any one of claims 1 to 3, and the method includes: Step 1: optical path calibration, using a spectrum shift and optical path calibration device to align the light source emitting device and the light source receiving device in the absorption spectrum detection device; Step 2, using an absorption spectrum detection device to obtain the absorption spectrum of the deposited sample during the deposition process; Step 3: performing in-situ detection on the deposited sample according to the acquired absorption spectrum of the deposited sample; The step 2 includes: Step 2.1, using an absorption spectrum detection device to obtain red light compensation spectra at different interval temperatures in a tubular CVD device without placing a sample; Step 2.2, obtaining the real-time absorption spectrum during the deposition process; In step 2.3, the final spectrum of the deposited sample is obtained by subtracting the red light compensation spectrum at the corresponding temperature from the real-time absorption spectrum.

5. The method according to claim 4, characterized in that The step 2.1 includes: Without placing any sample, at room temperature, allow the light path to pass through the quartz tube and quartz boat to reach the light source receiving device to obtain a spectrum, which is recorded as the initial spectrum; Increase the temperature gradually, starting from 100℃ Take a spectrum and subtract it from the initial spectrum to obtain the red light compensation spectrum under different temperature gradients.

6. The method according to claim 4, characterized in that The step 1 includes: using the first transverse stepper motor and the first longitudinal stepper motor to search for the position of the light source receiving device by traversing, and then using the second transverse stepper motor and the second longitudinal stepper motor to fine-tune the angle to maximize the intensity of the incident light.

7. A method for determining the growth window of a deposited sample, characterized in that: The method is implemented based on the system according to any one of claims 1 to 3, and the method includes: Step S1, optical path calibration, using a spectrum shift and optical path calibration device to align the optical paths of a light source emitting device and a light source receiving device in an absorption spectrum detection device; Step S2, controlling the light source emitting device and the light source receiving device to move along the moving track, and obtaining the absorption spectrum corresponding to the deposited sample at each position during the deposition process in real time; Step S3, determining the growth window of the deposited sample according to the absorption spectrum corresponding to the deposited sample at each position during the deposition process.

8. The method according to claim 7, characterized in that The step S3 comprises: The material growth at different positions is analyzed based on the absorption spectra corresponding to the deposited samples at various positions during the deposition process; The position where the material grows best is used as the growth window of the deposited sample.

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