A surface trap distribution testing method and device based on optical excitation

Abstract

The present application provides a surface trap distribution test method and device based on light excitation, which belongs to the technical field of dielectric property testing of solid medium materials. The method sends a preset excitation energy parameter to the electron gun device so that the electron gun device emits corresponding trapped charges to the sample to be tested within a first time period. The sample to be tested is a solid medium that is relatively arranged at the emission end of the electron gun device and the collection end of the surface potentiometer through an active connection device. When the trapped charge is injected into the sample to be tested, a light source excitation instruction is generated to enable the light source excitation device to emit preset wavelength photon streams to the sample to be tested in sequence through the light source excitation instruction. The surface potential sequence corresponding to the trapped charge is determined by the relatively arranged surface potentiometer. Based on the excitation energy parameter, the surface potential sequence, the preset trap energy level formula and the preset trap density distribution formula, the corresponding surface trap energy level value and surface trap density distribution value of the sample to be tested are determined.

Description

Technical Field

[0001] The present application relates to the technical field of dielectric property testing of solid medium materials, and in particular to a surface trap distribution testing method and device based on optical excitation. Background Art

[0002] Physical or chemical defects within semiconductor and dielectric materials manifest as localized energy levels between the valence and conduction bands in their band structures, known as traps or trap centers. The density of surface trap states in solid surfaces is much greater than that of bulk trap states due to chemical bond reconstruction, physical and chemical adsorption, and other factors. The complexity of these localized states dictates a wide energy spectrum for charge traps. Charges entering solid dielectrics are trapped by these traps, and the varying depths of these traps and the bound charges they contain significantly influence the macroscopic electrical properties of the material.

[0003] The basic principle for measuring the distribution of charge trap energy levels in dielectric materials is to first form space charge in the dielectric through charge injection, a process known as "trapping." Then, applying a stimulus (such as heat or light) to the dielectric causes the space charge to de-trap and recombine, a process known as "de-trapping." The space charge and its trapped state in the dielectric are indirectly characterized by observing changes in surface potential, current, light emission, and other related physical quantities.

[0004] Applicants have discovered that the influence of traps on the dielectric properties of materials is complex, and a clear theoretical framework describing this process is currently lacking. Therefore, accurate and in-depth testing of trap distribution is necessary. Current methods for measuring trap distribution are relatively simple, resulting in poor accuracy. These methods also tend to damage the dielectric material structure, leading to errors in the measurement results and hindering accurate performance testing, evaluation, and design of dielectric materials. Summary of the Invention

[0005] To solve the above problems, the embodiments of the present application provide a surface trap distribution testing method and device based on optical excitation, which are used to accurately and non-destructively test the trap distribution.

[0006] In one aspect, an embodiment of the present application provides a surface trap distribution testing method based on optical excitation, the method comprising:

[0007] The preset excitation energy parameters are sent to the electron gun device so that the electron gun device emits corresponding trapped charges to the sample to be tested within a first time period. The sample to be tested is a solid medium that is relatively arranged at the emission end of the electron gun device and the collection end of the surface potentiometer through an active connection device. When the trapped charges are injected into the sample to be tested, a light source excitation instruction is generated to cause the light source excitation device to sequentially emit a preset wavelength photon stream to the sample to be tested through the light source excitation instruction. The surface potential sequence corresponding to the trapped charges is determined by the relatively arranged surface potentiometer. Based on the excitation energy parameters, the surface potential sequence, the preset trap energy level formula, and the preset trap density distribution formula, the corresponding surface trap energy level value and surface trap density distribution value of the sample to be tested are determined.

[0008] In one implementation of the present application, a first drive instruction is sent to the movable connection device so that the movable connection device moves the stage to a first predetermined position and rotates the stage plane so that the center of the stage plane is located at and perpendicular to the extension line of the emission end. The stage is made of a conductive metal material, and the plane is adhered to the sample to be tested by conductive silicone grease. The shortest distance between the stage at the first predetermined position and the emission end of the electron gun device is the first predetermined distance. The method also includes: when the trapped charge is injected into the sample to be tested, a second drive instruction is sent to the movable connection device so that the movable connection device moves the stage to a second predetermined position and rotates the stage plane so that the center of the stage plane is located at and perpendicular to the surface potentiometer acquisition end. The shortest distance between the stage at the second predetermined position and the surface potentiometer acquisition end is the second predetermined distance.

[0009] In one implementation of the present application, a surface potentiometer is used to determine at least two surface potential values within a first time period, and the difference between the two surface potential values is determined as a trapping judgment value. If the trapping judgment value is less than a preset threshold, the corresponding trapped charge is determined to be injected into the sample under test. Otherwise, a trapping activation instruction is generated and sent to the electron gun device, causing the electron gun device to emit the corresponding charge into the sample under test until the trapping judgment value is less than the preset threshold.

[0010] In one implementation of the present application, a light source excitation device sequentially emits a stream of photons ranging from 215 nanometers to 2100 nanometers at a first time step. The photon stream from 215 nanometers to 2100 nanometers is monochromatic. A surface potential sequence corresponding to the trapped charge is determined using a surface potentiometer positioned opposite to the surface potentiometer. Specifically, the surface potentiometer sequentially collects surface potential values corresponding to the sample under test under illumination by the photon stream at a second time step to generate the surface potential sequence. The second time step is at least half the first time step.

[0011] In one implementation of the present application, the charge incidence depth value is determined based on the excitation energy parameters and the range empirical formula, so as to determine the corresponding surface trap energy level value and surface trap density distribution value of the sample to be tested based on the charge incidence depth value, the surface potential sequence, the trap energy level formula and the trap density distribution formula.

[0012] The empirical formula for range is as follows:

[0013]

[0014] Where δ is the charge impact depth. α, β, and γ are preset constants. E0 is the electron beam energy corresponding to the excitation energy parameter, in MeV. ρ is the density of the sample to be measured.

[0015] In one implementation of the present application, a surface potential curve equation corresponding to a second time period is determined based on the surface potential sequence. The second time period corresponds to the light source excitation duration corresponding to the light source excitation instruction. The charge incidence depth value and the surface potential curve equation are input into a trap density distribution formula to determine a number of surface trap density distribution values. Furthermore, the surface trap energy level value is determined based on a preset wavelength, photon flux frequency, and trap energy level formula corresponding to the light source excitation instruction.

[0016] The trap density distribution formula is as follows:

[0017]

[0018] Where N is the surface trap density distribution value. ε0 is the vacuum dielectric constant. r is the relative dielectric constant of the sample to be tested. L is the thickness of the sample to be tested. q is the electron charge. g is the proportional coefficient related to the charge excitation efficiency, the volume of the sample to be tested, and the electron charge. f0 is the preset initial occupancy of the electron trap. k is the Boltzmann constant. T is the absolute temperature. t is the time. V s is the surface potential curve equation.

[0019] In one implementation of the present application, the electron beam energy corresponding to the excitation energy parameter is 20 electron volts to 50 kiloelectron volts.

[0020] In one implementation of the present application, a set of charge incidence depth values is obtained from a preset database. Based on the set of charge incidence depth values and an empirical range formula, several excitation energy parameters are updated to determine several surface trap energy level values and corresponding surface trap density distribution values based on the updated excitation energy parameters. Based on the several charge incidence depth values and the corresponding surface trap energy level values and surface trap density distribution values, a trap distribution triplet is generated and transmitted to the corresponding user terminal.

[0021] In one implementation of the present application, a light source excitation device sequentially emits a photon stream ranging from 215 nanometers to 2100 nanometers at a first time step and a preset light step. Each first time step corresponds to a unique preset wavelength. The difference between the preset wavelengths of the photon streams corresponding to each first time step is an integer multiple of the light step.

[0022] On the other hand, an embodiment of the present application provides a surface trap distribution testing device based on optical excitation, the device comprising:

[0023] At least one processor; and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to:

[0024] The preset excitation energy parameters are sent to the electron gun device so that the electron gun device emits corresponding trapped charges to the sample to be tested within a first time period. The sample to be tested is a solid medium that is relatively arranged at the emission end of the electron gun device and the collection end of the surface potentiometer through an active connection device. When the trapped charges are injected into the sample to be tested, a light source excitation instruction is generated to cause the light source excitation device to sequentially emit a preset wavelength photon stream to the sample to be tested through the light source excitation instruction. The surface potential sequence corresponding to the trapped charges is determined by the relatively arranged surface potentiometer. Based on the excitation energy parameters, the surface potential sequence, the preset trap energy level formula, and the preset trap density distribution formula, the corresponding surface trap energy level value and surface trap density distribution value of the sample to be tested are determined.

[0025] The present application utilizes electron gun equipment, light source excitation equipment, and surface potentiometers to test the trapping and de-trapping processes of the sample to be tested, thereby obtaining a number of surface potential values of the sample to be tested under light excitation, and then determining the trap distribution of the sample to be tested, the trap distribution including: surface trap energy level value and surface trap density distribution value. The above scheme is used to accurately and non-destructively test the trap distribution; and the above scheme can adopt injection methods such as electron gun equipment bombardment to obtain the trap distribution by measuring the surface potential decay under light excitation conditions; and can gradually increase the output energy of the electron gun equipment to reflect the trap distribution of different charge incident depth values, and further accurately test the trap distribution. The light excitation method provided by the present application is an isothermal test, which can maintain the original characteristics of the surface trap energy level, and the trap itself is not affected during the entire measurement process.

[0026] In addition, the technical solution provided by the present application does not require the installation of metal electrodes on the stage where the sample to be tested is located, and can complete the trap distribution test, thereby avoiding the band bending problem caused by the contact between the metal electrode and the dielectric material, thereby not changing the intrinsic band results on the surface of the dielectric material, and testing the trap distribution without damaging the material, accurately reflecting the trap characteristics of the material surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 This is a structural schematic diagram of a device corresponding to a surface trap distribution testing method based on light excitation in an embodiment of the present application;

[0029] Figure 2 A schematic diagram of a flow chart of a surface trap distribution testing method based on optical excitation in an embodiment of the present application;

[0030] Figure 3 This is a top view of a vacuum chamber of a surface trap distribution testing device based on optical excitation in an embodiment of the present application;

[0031] Figure 4 This is a side view of a vacuum chamber of a surface trap distribution testing device based on optical excitation in an embodiment of the present application;

[0032] Figure 5 This is a side cross-sectional view of a vacuum chamber of a surface trap distribution testing device based on optical excitation in an embodiment of the present application;

[0033] Figure 6 This is a top-down cross-sectional view of a surface trap distribution testing device based on optical excitation in an embodiment of the present application;

[0034] Figure 7 This is a structural schematic diagram of a surface trap distribution testing device based on light excitation in an embodiment of the present application. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] In order to conduct accurate and convenient trap distribution testing and avoid the measurement drawbacks of existing measurement methods, such as the band bending caused by the contact between metal electrodes and dielectric materials, the embodiments of the present application provide a surface trap distribution testing method and equipment based on light excitation, which is used to accurately and conveniently test the surface trap distribution of solid dielectric materials.

[0037] The following describes in detail various embodiments of the present application with reference to the accompanying drawings.

[0038] The schematic diagram of the device for the surface trap distribution test method based on optical excitation is shown in Figure 1 As shown in the figure, a flow chart of a surface trap distribution test method based on optical excitation is shown in Figure 2 As shown, the device includes: a light source excitation device (a light source excitation device transmitting end 1, a light source modulation system 9: a light source 91, a beam expander 92, a spectrometer 93, a light detector 94, a light output side 95, and an optical fiber 96), a surface potentiometer acquisition end 2, a data acquisition system 10 (an electrostatic potentiometer model is TREK341B-101, and an NI acquisition card 102), an electron gun device transmitting end 3 (an electron gun device control system 8: an NI DAQ acquisition card 81, a pulse signal generating unit 82, and a timing controller 83), a sample to be tested 4, conductive silicone grease 5, a stage 6 (the stage 6 is located in a movable connection device to realize the movement and rotation of the position of the stage 6, so that the sample to be tested on the stage is relatively arranged at the electron gun device transmitting end and the surface potentiometer acquisition end through the movable connection device, such as the first predetermined position and the second predetermined position), a vacuum chamber 7, and a processing unit 11, wherein the processing unit 11 can be a server, a computer, and other equipment.

[0039] It should be noted that in the following embodiments of this application, the server is used as the execution entity of the surface trap distribution testing method based on light excitation. This is only for illustrative purposes. The execution entity is not limited to the server, and this application does not make any specific restrictions on this.

[0040] In addition, the cross-sectional view of the vacuum chamber 7 of the present application is as follows Figure 3-Figure 6 , Figure 3 This is a top view of the vacuum cavity, in which the vacuum cavity has openings at the light source excitation device emission end 1, the surface potentiometer collection end 2, and the electron gun device emission end 3. The diameters of each opening match the diameters of the light source excitation device emission end 1, the surface potentiometer collection end 2, and the electron gun device emission end 3, respectively. Figure 4 This is a side view of the vacuum chamber. There are angle deviations between the three openings. Figure 1 ; Figure 5 is a side sectional view of the vacuum chamber, where A is the central axis; Figure 6 The vacuum chamber 7 provides a vacuum degree of at least 10 -6 Pa.

[0041] The present invention provides a method for testing surface trap distribution based on optical excitation. Figure 2 As shown, the method may include steps S201-S204:

[0042] S201 : The server sends a preset excitation energy parameter to an electron gun device, so that the electron gun device emits corresponding trapped charges to a sample to be tested within a first time period.

[0043] The sample to be tested is a solid medium which is relatively arranged at the emission end of the electron gun device and the collection end of the surface potentiometer through a movable connection device.

[0044] That is, the server can send the excitation energy parameters to the electron gun device. The electron gun device control system 8, which includes the NI DAQ acquisition card 81, the pulse signal generation unit 82, and the timing controller 83, generates a trapped charge emission pulse with a pulse width and beam current intensity corresponding to the excitation energy parameters. The pulse is continuously emitted to the sample under test during a first time period, thereby emitting trapped charge to the sample under test. The first time period is preset, such as 5 minutes, and can be understood as the duration required to ensure that the trapped charge is emitted to the sample under test and the trapping process is completed.

[0045] Among them, the pulse width can be between 10 nanoseconds and 1 millisecond, the current of the electron gun device is in the nanoampere level, the electron beam energy corresponding to the excitation energy parameter can be 20eV-50keV, and there is a corresponding relationship between the excitation energy parameter and the electron beam energy. By adjusting the excitation energy parameter, the server can adjust the electron beam energy output by the electron gun device accordingly.

[0046] In one embodiment of the present application, when the electron gun device emits corresponding trapped charges to the sample to be tested, the bottom end of the emission end of the electron gun device is 50 mm away from the sample to be tested, and when the electron gun device emits a pulse, the movable connection device causes the sample to be tested carried by the stage to be located at an extension line of the emission end of the electron gun device and perpendicular to the extension line of the emission end of the electron gun device.

[0047] In another embodiment of the present application, the sample to be tested includes but is not limited to: polyimide, polyethylene, polytetrafluoroethylene, epoxy resin or alumina ceramics.

[0048] In an embodiment of the present application, the server sends a preset excitation energy parameter to the electron gun device so that the electron gun device emits corresponding trapped charges to the sample to be tested within the first time period. The method further includes:

[0049] The server sends a first drive command to the articulating mechanism, causing the articulating mechanism to move the stage to a first predetermined position and rotate the stage plane so that the center of the stage plane is located perpendicular to an extension line of the emission end. The stage is made of a conductive metal material and is adhered to the sample to be tested using conductive silicone grease. The shortest distance between the stage at the first predetermined position and the emission end of the electron gun device is the first predetermined distance.

[0050] Among them, the first predetermined position refers to the bottom end of the emission end of the above-mentioned electron gun device, which is a first predetermined distance away from the sample to be tested, such as 50 mm, and when the electron gun device emits a pulse, the movable connection device makes the position of the sample to be tested carried by the stage located on the extension line of the emission end of the electron gun device and perpendicular to the extension line of the emission end of the electron gun device.

[0051] The stage provided in this application can complete the trap distribution test without setting up metal electrodes, avoiding the band bending problem caused by the contact between the metal electrodes and the dielectric material, thereby not changing the intrinsic band results of the dielectric material surface and accurately reflecting the trap characteristics of the material surface.

[0052] In another embodiment of the present application, after the server sends the preset excitation energy parameters to the electron gun device, the method further includes:

[0053] The server can determine at least two surface potential values within the first time period through a surface potentiometer, and determine a difference between the two corresponding surface potential values as a trap determination value.

[0054] Next, when the trapping judgment value is less than a preset threshold, the server determines that the corresponding trapping charge is injected into the sample to be tested.

[0055] Otherwise, a trapping excitation instruction is generated and sent to the electron gun device, so that the electron gun device emits corresponding charges to the sample to be tested until the trapping judgment value is less than the preset threshold.

[0056] That is, during the first time period, based on the pulse interval of the electron gun device, the server can move and rotate the stage to a second predetermined position at the end of a pulse of the electron gun device. The surface potentiometer collects the surface potential value a of the sample under test after the end of the pulse and compares it with the surface potential value b collected after the end of the previous pulse to calculate a trapping judgment value. If the trapping judgment value is less than a preset threshold, it is determined that the corresponding trapped charge has been injected into the sample under test. The preset threshold is pre-set and is not specifically limited in this application.

[0057] If the trapping judgment value is less than the preset threshold, the first drive instruction is regenerated, and the electron gun device emits another pulse to the sample under test. The surface potential meter then repeats the process of collecting the surface potential value c. The difference between the surface potential value c and the surface potential value a is calculated as the trapping judgment value, and a determination is made as to whether the trapping judgment value meets the above conditions. These steps are repeated until the trapping judgment value is less than the preset threshold, confirming that the sample under test has been trapped. The first period is then determined to have ended, and the subsequent de-trapping operation continues.

[0058] In the embodiment of the present application, the server can move the position of the stage to the second predetermined position of the surface potentiometer as follows:

[0059] When trapped charge is injected into the sample to be tested, the server sends a second drive instruction to the articulating mechanism, causing the articulating mechanism to move the stage to a second predetermined position and rotate the stage plane so that the center of the stage plane is located at and perpendicular to the surface potentiometer acquisition terminal. The shortest distance between the stage and the surface potentiometer acquisition terminal at the second predetermined position is the second predetermined distance.

[0060] The surface potentiometer is preferably a high-voltage, high-speed surface potentiometer with a measurement range of 0 to ±20 kV, an accuracy better than ±0.1%, and a response speed of less than 200 microseconds per kV. The second predetermined distance may be 1 mm to 3 mm.

[0061] S202 , when the trapped charge is injected into the sample to be tested, the server generates a light source excitation instruction, so as to enable the light source excitation device to sequentially emit a preset wavelength photon stream to the sample to be tested through the light source excitation instruction.

[0062] In the embodiment of the present application, the emission end of the light source excitation device is preferably 10 mm away from the surface of the sample to be measured.

[0063] The light source excitation device can sequentially emit a photon flow of 215 nm to 2100 nm to the sample to be tested at a first time step. The photon flow of 215 nm to 2100 nm is monochromatic light. The luminous flux density of the monochromatic light is on the order of 10 24 cm -2 s -1 Above the magnitude.

[0064] In addition, the light source excitation device sequentially emits a photon stream of 215 nm to 2100 nm at a first time step, specifically including:

[0065] The light source excitation device sequentially emits a photon stream with a wavelength between 215 nanometers and 2100 nanometers at a first time step and a preset light step. Each first time step corresponds to a unique preset wavelength. The difference between the preset wavelengths of the photon streams corresponding to each first time step is an integer multiple of the light step.

[0066] In other words, if the first time step is 2 nanoseconds and the optical step size is 5 nanometers, the light source laser device can scan the sample under test with a photon flux of 215 nanometers for the first time period of 0-2 nanoseconds. At 2 nanoseconds, the first time step is met, and the wavelength of the light is adjusted. The adjustment of the light wavelength is based on the optical step size. That is, at 2 nanoseconds, the photon flux emitted by the light source excitation device has a wavelength of 220 nanometers. Following these steps, the light wavelength is adjusted sequentially until the wavelength reaches 2100 nanometers or the surface potential of the sample under test reaches zero.

[0067] The preset wavelength difference of the photon flow corresponding to each first time step is an integer multiple of the optical step length. Taking the optical step length of 5 nanometers as an example, the preset wavelength difference between the m-th and m+1-th time steps is 5, and the preset wavelength difference between the m-th and n-th time steps is 5l, where l is an integer.

[0068] S203: The server determines the surface potential sequence corresponding to the trapped charge through relatively arranged surface potentiometers.

[0069] In the embodiment of the present application, the server determines the surface potential sequence corresponding to the trapped charge through relatively arranged surface potentiometers, specifically including:

[0070] The surface potential meter sequentially collects surface potential values corresponding to the sample under the irradiation of the photon stream at a second time step to generate a surface potential sequence. The second time step is at least less than half of the first time step.

[0071] In other words, during the process of the photon flow irradiating the sample to be measured, the surface potential meter will acquire the surface potential value of the sample to be measured once in the second time step, thereby obtaining the surface potential value of the sample to be measured in real time.

[0072] The first time step is at least twice the second time step. For example, if the first time step is 2 nanoseconds, the second time step is 1 nanosecond. That is, within a first time step, the server can obtain two surface potential values, such as x1 and x2, collected under a photon flux scan of the same wavelength. The server then averages the surface potential values x1 and x2 for the same wavelength, averaging the values to obtain the surface potential value x3 (x1 + x2) / 2 for that wavelength.

[0073] Subsequently, the server arranges the surface potential values x3 corresponding to each wavelength in chronological order into a surface potential sequence, such as the surface potential sequence [a3, b3, c3, ..., x3, ..., n3].

[0074] This application does not limit the specific value of the second time step. The first time step can be 3 times, 4 times, etc. of the second time step, and this application does not impose any specific limitation on this.

[0075] S204 , the server determines the surface trap energy level value and surface trap density distribution value corresponding to the sample to be tested based on the excitation energy parameter, the surface potential sequence, the preset trap energy level formula and the preset trap density distribution formula.

[0076] In the embodiment of the present application, the server determines the surface trap energy level value and surface trap density distribution value corresponding to the sample to be tested based on the excitation energy parameter, the surface potential sequence, the trap energy level formula, and the trap density distribution formula, specifically including:

[0077] The server determines the charge incidence depth value based on the excitation energy parameter and the range empirical formula, and determines the corresponding surface trap energy level value and surface trap density distribution value of the sample to be tested based on the charge incidence depth value, surface potential sequence, trap energy level formula and trap density distribution formula.

[0078] The empirical formula for range is as follows:

[0079]

[0080] Where δ is the charge incident depth. α, β, and γ are preset constant values, and α is 0.55 g / cm 2 MeV -1 , is 0.9841, which is 3MeV -1 E0 is the electron beam energy corresponding to the excitation energy parameter, and its energy unit is MeV. ρ is the density of the sample to be measured.

[0081] That is to say, the present application relies on the above-mentioned range empirical formula to determine the charge incidence depth value corresponding to the energy output by the electron gun device.

[0082] Similarly, after the charge incident depth value is determined, the excitation energy parameters that need to be sent to the electron gun device can also be determined.

[0083] Next, the server determines the corresponding surface trap energy level value and surface trap density distribution value of the sample to be tested based on the charge incidence depth value, surface potential sequence, trap energy level formula, and trap density distribution formula, specifically including:

[0084] First, the server determines the surface potential curve equation corresponding to the second period based on the surface potential sequence. The second period is the light source excitation duration corresponding to the light source excitation instruction, that is, the scanning duration of the light source excitation device.

[0085] The server then inputs the charge incident depth value and the surface potential curve equation into the trap density distribution formula to determine several surface trap density distribution values. It also determines the surface trap energy level value based on the preset wavelength, photon flux frequency, and trap energy level formula corresponding to the light source excitation instruction.

[0086] Among them, the preset trap density distribution formula is as follows:

[0087]

[0088] Where N is the surface trap density distribution value. ε0 is the vacuum dielectric constant. r is the relative dielectric constant of the sample to be tested. L is the thickness of the sample to be tested. q is the electron charge. g is the proportional coefficient related to the charge excitation efficiency, the volume of the sample to be tested, and the electron charge. f0 is the preset initial occupancy of the electron trap. k is the Boltzmann constant. T is the absolute temperature. t is the time. V s is the surface potential curve equation.

[0089] The default trap energy level formula is as follows:

[0090]

[0091] Where h is Planck's constant, v is the frequency of the photon stream, c is the speed of light, and λ is the wavelength of the photon stream.

[0092] In order to accurately study the surface defect distribution and obtain the relationship between different charge incidence depth values and trap distribution, the following embodiments were adopted, which specifically include:

[0093] First, the server obtains a set of charge incident depth values from a preset database.

[0094] The charge incidence depth value set includes a number of different charge incidence depth values.

[0095] Next, the server updates a plurality of excitation energy parameters according to the charge incidence depth value set and the range empirical formula, so as to determine a plurality of surface trap energy level values and corresponding surface trap density distribution values according to the updated plurality of excitation energy parameters.

[0096] That is to say, by relying on different excitation energy parameters calculated by the range empirical formula, the specific steps of the above-mentioned surface trap distribution test method based on light excitation can be executed to obtain several surface trap energy level values and corresponding surface trap density distribution values.

[0097] Subsequently, the server generates a trap distribution triplet according to a number of charge incident depth values and corresponding surface trap energy level values and surface trap density distribution values, and sends the trap distribution triplet to the corresponding user terminal.

[0098] The trap distribution triplet is {charge incidence depth value, surface trap energy level value, surface trap density distribution value}. The user terminal can be a mobile phone, computer or other device of the person conducting the test. This application does not specifically limit the specific type of device.

[0099] In addition, the surface trap distribution test device based on light excitation is in a room temperature environment. This application uses the photon flow emitted by the light source excitation device to achieve light excitation, and performs surface trap distribution testing under isothermal conditions, which can maintain the original characteristics of the trap energy level, and the trap itself is not affected during the entire measurement process.

[0100] This application utilizes an electron gun device, a light source excitation device, and a surface potentiometer to test the sample's trapping and de-trapping processes, thereby obtaining a number of surface potential values of the sample under light excitation, and then determining the trap distribution of the sample, including surface trap energy level values and surface trap density distribution values. The above scheme can accurately and non-destructively test the trap distribution without the need for metal electrodes, thus avoiding the band bending problem caused by the contact between the metal electrode and the dielectric material. This does not change the intrinsic band results of the dielectric material surface, and the trap distribution is tested without material damage, accurately reflecting the trap characteristics of the material surface.

[0101] Figure 7 This is a schematic diagram of the results of a surface trap distribution test device based on optical excitation provided in an embodiment of the present application. The device includes:

[0102] At least one processor; and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to:

[0103] The preset excitation energy parameters are sent to the electron gun device so that the electron gun device emits corresponding trapped charges to the sample to be tested within a first time period. The sample to be tested is a solid medium that is relatively arranged at the emission end of the electron gun device and the collection end of the surface potentiometer through an active connection device. When the trapped charges are injected into the sample to be tested, a light source excitation instruction is generated to cause the light source excitation device to sequentially emit a preset wavelength photon stream to the sample to be tested through the light source excitation instruction. The surface potential sequence corresponding to the trapped charges is determined by the relatively arranged surface potentiometer. Based on the excitation energy parameters, the surface potential sequence, the preset trap energy level formula, and the preset trap density distribution formula, the corresponding surface trap energy level value and surface trap density distribution value of the sample to be tested are determined.

[0104] The various embodiments in this application are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the device embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0105] The device and method provided in the embodiments of the present application correspond one to one, and therefore, the device also has similar beneficial technical effects as its corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the device will not be repeated here.

[0106] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0107] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A surface trap distribution testing method based on optical excitation, characterized in that: The method comprises: Sending a preset excitation energy parameter to an electron gun device so that the electron gun device emits corresponding trapped charges to a sample to be tested within a first time period; wherein the sample to be tested is a solid medium disposed relative to an emission end of the electron gun device and a collection end of a surface potentiometer via an movable connection device; When the trapped charge is injected into the sample to be tested, a light source excitation instruction is generated, so as to enable the light source excitation device to sequentially emit a preset wavelength photon stream toward the sample to be tested through the light source excitation instruction; determining a surface potential sequence corresponding to the trapped charges by using the surface potentiometers arranged opposite to each other; Based on the excitation energy parameter, the surface potential sequence, the preset trap energy level formula and the preset trap density distribution formula, the surface trap energy level value and the surface trap density distribution value corresponding to the sample to be tested are determined.

2. The method according to claim 1, characterized in that Sending the preset excitation energy parameter to the electron gun device so that the electron gun device emits corresponding trapped charges to the sample to be tested within the first time period, the method further includes: Sending a first drive instruction to the movable connection device to cause the movable connection device to move its stage to a first predetermined position and rotate the stage plane so that the center of the stage plane is located at and perpendicular to the extension line of the emission end; wherein the stage is made of a conductive metal material and the plane is bonded to the sample to be tested by conductive silicone grease; and the shortest distance between the stage at the first predetermined position and the emission end of the electron gun device is a first predetermined distance; The method further comprises: When the trapped charge is injected into the sample to be tested, a second driving instruction is sent to the movable connection device to cause the movable connection device to move the stage to a second predetermined position and rotate the stage plane so that the center of the stage plane is located at and perpendicular to the surface potentiometer collection end; wherein the shortest distance between the stage at the second predetermined position and the surface potentiometer collection end is the second predetermined distance.

3. The method according to claim 1, characterized in that After sending the preset excitation energy parameters to the electron gun device, the method further includes: determining, by means of the surface potentiometer, at least two surface potential values within the first time period, and determining a difference between the two surface potential values as a trap determination value; When the trapping judgment value is less than a preset threshold, determining that the corresponding trapped charge is injected into the sample to be tested; Otherwise, a trapping excitation instruction is generated and sent to the electron gun device, so that the electron gun device emits corresponding charges to the sample to be tested until the trapping judgment value is less than the preset threshold.

4. The method according to claim 1, characterized in that The method includes sequentially emitting a preset wavelength photon stream to the sample to be tested, specifically comprising: The light source excitation device sequentially emits a photon stream of 215 nanometers to 2100 nanometers at a first time step; wherein the photon stream of 215 nanometers to 2100 nanometers is monochromatic light; Determining the surface potential sequence corresponding to the trapped charge by the relatively arranged surface potentiometers specifically includes: The surface potentiometer sequentially collects the corresponding surface potential values of the sample to be tested under the irradiation of the photon flow in a second time step to generate the surface potential sequence; the second time step is at least less than half of the first time step.

5. The method according to claim 1, characterized in that: Determining the surface trap energy level value and surface trap density distribution value corresponding to the sample to be tested based on the excitation energy parameter, the surface potential sequence, the trap energy level formula, and the trap density distribution formula specifically includes: Determine the charge incidence depth value according to the excitation energy parameter and the range empirical formula, and determine the surface trap energy level value and surface trap density distribution value corresponding to the sample to be tested according to the charge incidence depth value, the surface potential sequence, the trap energy level formula and the trap density distribution formula; The empirical formula for the range is as follows: Among them, δ is the charge incidence depth value; α, β, and γ are preset constant values respectively; E0 is the electron beam energy corresponding to the excitation energy parameter, and its energy unit is MeV; ρ is the density of the sample to be tested.

6. The method according to claim 5, characterized in that Determining the surface trap energy level value and surface trap density distribution value corresponding to the sample to be tested according to the charge incidence depth value, the surface potential sequence, the trap energy level formula, and the trap density distribution formula, specifically includes: Determining a surface potential curve equation corresponding to a second time period according to the surface potential sequence; the second time period being the light source excitation duration corresponding to the light source excitation instruction; Inputting the charge incidence depth value and the surface potential curve equation into the trap density distribution formula to determine a plurality of surface trap density distribution values; and Determining the surface trap energy level value according to the preset wavelength, photon flux frequency and trap energy level formula corresponding to the light source excitation instruction; The trap density distribution formula is as follows: Wherein, N is the surface trap density distribution value; ε0 is the vacuum dielectric constant; ε r is the relative dielectric constant of the sample to be tested; L is the thickness of the sample to be tested; q is the electron charge; g is the proportional coefficient related to the charge excitation efficiency, the volume of the sample to be tested, and the electron charge; f0 is the preset initial occupancy of the electron trap; k is the Boltzmann constant; T is the absolute temperature; t is the time; V s is the surface potential curve equation.

7. The method according to claim 5, characterized in that The electron beam energy corresponding to the excitation energy parameter is 20 electron volts to 50 kiloelectron volts.

8. The method according to claim 1, characterized in that: The method further comprises: Obtain a set of charge incident depth values from a preset database; updating the plurality of excitation energy parameters according to the charge incidence depth value set and the range empirical formula, so as to determine the plurality of surface trap energy level values and the corresponding surface trap density distribution values according to the updated plurality of excitation energy parameters; A trap distribution triplet is generated according to a number of charge incidence depth values and the corresponding surface trap energy level values and the surface trap density distribution value, and the trap distribution triplet is sent to a corresponding user terminal.

9. The method according to claim 4, characterized in that: The light source excitation device sequentially emits a photon stream from 215 nm to 2100 nm at a first time step, specifically comprising: The light source excitation device sequentially emits a photon stream ranging from 215 nanometers to 2100 nanometers in the first time step and the preset light step; wherein each first time step corresponds to a unique preset wavelength; and the difference in the preset wavelengths of the photon streams corresponding to each first time step is an integer multiple of the light step.

10. A surface trap distribution testing device based on optical excitation, characterized in that: The device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to: Sending a preset excitation energy parameter to an electron gun device so that the electron gun device emits corresponding trapped charges to a sample to be tested within a first time period; wherein the sample to be tested is a solid medium disposed relative to an emission end of the electron gun device and a collection end of a surface potentiometer via an movable connection device; When the trapped charge is injected into the sample to be tested, a light source excitation instruction is generated, so as to enable the light source excitation device to sequentially emit a preset wavelength photon stream toward the sample to be tested through the light source excitation instruction; determining a surface potential sequence corresponding to the trapped charges by using the surface potentiometers arranged opposite to each other; Based on the excitation energy parameter, the surface potential sequence, the preset trap energy level formula and the preset trap density distribution formula, the surface trap energy level value and the surface trap density distribution value corresponding to the sample to be tested are determined.

Images