Microscopic imaging device and method for characterizing photocurrent diffusion of photoelectric detector

Abstract

The invention discloses a device and a method for characterizing photocurrent diffusion microscopic imaging of a photoelectric detector. The device comprises a first laser source, a second laser source, a light path assembly, a sample table, a camera module and a processing module, the first laser source generates a first laser beam which irradiates a semiconductor sample carried by the sample table through the light path assembly; the second laser source generates a second laser beam which irradiates the semiconductor sample carried by the sample table through the light path assembly; the camera module is used for shooting the surface of the semiconductor sample carried by the sample table; the processing module is connected with the semiconductor sample; the processing module is used for determining a diffusion light current area of the semiconductor sample according to a light current signal generated when the semiconductor sample is irradiated by the first laser beam; controlling the first laser beam and the second laser beam to irradiate a diffusion light current area of the semiconductor sample by using a camera module so as to obtain a diffusion light current signal of the semiconductor sample; and obtaining photocurrent distribution information of the semiconductor sample according to the diffusion photocurrent signal of the semiconductor sample.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor device testing and characterization, and in particular to a device and method for characterizing photocurrent diffusion microscopy of a photodetector. Background Art

[0002] Laser Beam Induced Current (LBIC) is a method for detecting photocurrent diffusion microscopy imaging of semiconductor samples. This method can provide detailed information about the photocurrent distribution and transmission characteristics inside the semiconductor sample, thereby helping to analyze the performance of the device and identify possible defects. The principle of this method is to use a focused laser to irradiate the surface of the semiconductor sample, and control the position of the laser spot on the surface of the semiconductor sample through a precise mobile mechanical device (such as an XY platform) to achieve a systematic scan of the entire surface. Under laser irradiation, the semiconductor sample will generate a photocurrent. By connecting to a current signal measuring device (such as a computer device) connected to the semiconductor sample, the size of the photocurrent generated can be measured at each spot position. The photocurrent data measured at different positions are collected, and the data are analyzed by software to obtain a spatial distribution image of the photocurrent.

[0003] LBIC technology has the advantages of high resolution, non-direct contact, and easy operation, and is widely used in the research of photovoltaic devices such as solar cells and photodetector arrays. However, the currently public LBIC can only obtain the photocurrent signal of semiconductor samples, and the accuracy of the photocurrent distribution information obtained based only on the photocurrent signal is low. Summary of the invention

[0004] To this end, this application discloses the following technical solutions:

[0005] The first aspect of the present application provides a microscopic imaging device for characterizing photocurrent diffusion of a photodetector, comprising:

[0006] A first laser source, a second laser source, an optical path component, a sample stage, a camera module and a processing module;

[0007] The first laser source is used to generate a first laser beam that is irradiated to the semiconductor sample carried by the sample stage through the optical path component;

[0008] The second laser source is used to generate a second laser beam that passes through the optical path component and irradiates the semiconductor sample carried by the sample stage;

[0009] The camera module is used to photograph the surface of the semiconductor sample carried by the sample stage;

[0010] The processing module is connected to the semiconductor sample;

[0011] The processing module is used for:

[0012] determining a diffusion photocurrent region of the semiconductor sample according to a photocurrent signal when the semiconductor sample is irradiated by a first laser beam;

[0013] Using the camera module to control the first laser beam and the second laser beam to irradiate the diffuse photocurrent region of the semiconductor sample to obtain a diffuse photocurrent signal of the semiconductor sample;

[0014] Photocurrent distribution information of the semiconductor sample is obtained according to the diffuse photocurrent signal of the semiconductor sample.

[0015] Optionally, the optical path assembly includes a first reflector, a laser beam combiner, a laser beam expander, a second reflector, a beam splitter and a microscope objective lens;

[0016] The first laser beam is irradiated to the semiconductor sample carried by the sample stage through the optical path component, including:

[0017] The first laser beam passes through the laser beam combiner, the laser beam expander, the second reflector, the beam splitter and the microscope objective lens in sequence, and irradiates the semiconductor sample carried by the sample stage;

[0018] The second laser beam is irradiated to the semiconductor sample carried by the sample stage through the optical path component, including:

[0019] After being reflected by the first reflector, the second laser beam passes through the laser beam combiner, the laser beam expander, the second reflector, the beam splitter and the microscope objective lens in sequence, and irradiates the semiconductor sample carried by the sample stage.

[0020] Optionally, the optical path component further includes a chopper, which is located between the laser beam combiner and the laser beam expander, and is used to chop and modulate the continuous laser beam passing through the laser beam combiner to obtain a pulsed laser beam.

[0021] Optionally, it further comprises a lock-in amplifier, wherein the lock-in amplifier is connected to the chopper;

[0022] The processing module is connected to the semiconductor sample via the lock-in amplifier;

[0023] The lock-in amplifier is used to amplify the target frequency signal in the photocurrent signal and the diffused photocurrent signal generated by the semiconductor sample according to the target frequency output by the chopper.

[0024] Optionally, the first laser source includes a supercontinuum laser and a supercontinuum laser light source control power supply, and the second laser source includes a continuous laser light source.

[0025] Optionally, the wavelength of the second laser beam generated by the continuous laser light source is any one of 1064 nm, 852 nm, 532 nm and 405 nm.

[0026] Optionally, the processing module is further used for:

[0027] Different scanning step lengths are configured for different areas of the semiconductor sample.

[0028] The second aspect of the present application provides a method for characterizing photocurrent diffusion microscopy of a photodetector, comprising:

[0029] determining a diffusion photocurrent region of the semiconductor sample according to a photocurrent signal when the semiconductor sample is irradiated by a first laser beam;

[0030] Using a camera module to control the first laser beam and the second laser beam to irradiate the diffuse photocurrent region of the semiconductor sample to obtain a diffuse photocurrent signal of the semiconductor sample;

[0031] Photocurrent distribution information of the semiconductor sample is obtained according to the diffuse photocurrent signal of the semiconductor sample.

[0032] Optionally, the step of controlling the first laser beam and the second laser beam to irradiate the diffused photocurrent region of the semiconductor sample using a camera module to obtain a diffused photocurrent signal of the semiconductor sample includes:

[0033] Using a camera module to control the first laser beam to irradiate the diffuse photocurrent region of the semiconductor sample to obtain a first diffuse photocurrent signal of the semiconductor sample;

[0034] Using a camera module to control the first laser beam and the second laser beam to simultaneously irradiate the diffusion photocurrent region of the semiconductor sample to obtain a second diffusion photocurrent signal of the semiconductor sample;

[0035] The step of obtaining the photocurrent distribution information of the semiconductor sample according to the diffused photocurrent signal of the semiconductor sample comprises:

[0036] Obtaining first photocurrent distribution information of the semiconductor sample according to a first diffuse photocurrent signal of the semiconductor sample;

[0037] Second photocurrent distribution information of the semiconductor sample is obtained according to the second diffused photocurrent signal of the semiconductor sample.

[0038] Optionally, also include:

[0039] Comparative information characterizing the photoelectric characteristics inside the semiconductor sample is obtained based on the first photocurrent distribution information and the second photocurrent distribution information.

[0040] The beneficial effects of this solution are:

[0041] This solution can not only obtain the photocurrent signal of the semiconductor sample, but also quickly calibrate the diffuse photocurrent area based on the photocurrent signal, and then control the first laser beam and the second laser beam to irradiate the diffuse photocurrent area of ​​the semiconductor sample through the camera module to obtain the diffuse photocurrent signal of the semiconductor sample, and then obtain photocurrent distribution information with higher precision and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0043] Figure 1 It is a structural schematic diagram of a photocurrent diffusion microscopic imaging device for characterizing a photodetector provided in an embodiment of the present application;

[0044] Figure 2 This is a workflow diagram of a device for characterizing photocurrent diffusion microscopy of a photodetector provided in an embodiment of the present application;

[0045] Figure 3 It is a flow chart of a method for characterizing photocurrent diffusion microscopy imaging of a photodetector provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] The semiconductor sample used in any embodiment of the present application may be a semiconductor sample used to manufacture a solar cell or a semiconductor sample used to manufacture a photodetector.

[0048] The present application embodiment provides a microscopic imaging device for characterizing the diffusion of photocurrent of a photodetector, see Figure 1 , which is a schematic diagram of the structure of the device.

[0049] The device may include a first laser source, a second laser source 3 , an optical path component, a sample stage 12 , a camera module 13 and a processing module 15 .

[0050] The first laser source is used to generate a first laser beam that is irradiated to the semiconductor sample carried by the sample stage through the optical path component;

[0051] The second laser source is used to generate a second laser beam that is irradiated to the semiconductor sample carried by the sample stage through the optical path component;

[0052] The camera module is used to photograph the surface of the semiconductor sample carried by the sample stage;

[0053] Processing module and semiconductor sample connection;

[0054] Processing modules are used to:

[0055] determining a diffusion photocurrent region of the semiconductor sample according to a photocurrent signal when the semiconductor sample is irradiated by the first laser beam;

[0056] Using a camera module to control the first laser beam and the second laser beam to irradiate the diffusion photocurrent region of the semiconductor sample to obtain a diffusion photocurrent signal of the semiconductor sample;

[0057] The photocurrent distribution information of the semiconductor sample is obtained according to the diffuse photocurrent signal of the semiconductor sample.

[0058] The processing module 15 may be a computer device or other device with equivalent processing and control capabilities.

[0059] The camera module 13 may be a CCD camera or other device with camera capability.

[0060] Further, such as Figure 1 As shown, the optical path component may include a first reflecting mirror 4 , a laser beam combiner 5 , a laser beam expander 7 , a second reflecting mirror 8 , a beam splitter 9 and a microscope objective 10 .

[0061] The first laser beam is irradiated to the semiconductor sample carried by the sample stage through the optical path component, including:

[0062] The first laser beam passes through a laser beam combiner, a laser beam expander, a second reflector, a beam splitter and a microscope objective lens in sequence, and irradiates a semiconductor sample carried by a sample stage.

[0063] That is to say, the light beam generated by the first laser source passes through the beam combiner 5 to the beam expander 7, and then passes through the second reflector 8 to the beam splitter 9, enters the microscope objective 10 and is focused to the surface of the semiconductor sample 11 placed on the electric two-dimensional translation stage 12, so as to excite electron-hole pairs in the sample, thereby generating photocurrent and determining the diffusion area.

[0064] The second laser beam is irradiated to the semiconductor sample carried by the sample stage through the optical path component, including:

[0065] After being reflected by the first reflecting mirror, the second laser beam passes through the laser beam combiner, the laser beam expander, the second reflecting mirror, the beam splitter and the microscope objective lens in sequence, and irradiates the semiconductor sample carried by the sample stage.

[0066] The light beam generated by the second laser source passes through the first reflector 4 and the beam combiner 5 to enter the first optical axis (i.e., the optical axis where the first laser beam is located), and then passes through the beam expander 7 and is reflected by the second reflector 8, enters the beam splitter 9 and then is incident on the microscope objective lens 10, and is irradiated onto the semiconductor sample 11 through the microscope objective lens 10 to characterize the photocurrent signal of the diffusion area.

[0067] Among them, Figure 1 As shown, optionally, the first laser source may include a supercontinuum laser 1 and a supercontinuum laser light source control power supply 2, and the second laser source includes a continuous laser light source. The supercontinuum laser light source control power supply is used to provide a signal source for the supercontinuum laser, and the supercontinuum laser 1 outputs laser light under the control of the signal source.

[0068] The laser beam combiner 5 is placed after the first laser source and the second laser source, and is used to combine the two laser beams to ensure that the positions where the two laser beams are irradiated on the sample are consistent.

[0069] The microscope objective 10 is used to focus the laser beams output by the first laser source and the second laser source, so as to form a micrometer-scale light spot on the surface of the semiconductor sample. Compared with the shortcomings of the traditional scanning photocurrent spectrum system such as low resolution and sensitivity, the use of the microscope objective 10 to focus the laser beam to obtain a micrometer-scale light spot can greatly improve the spatial resolution of the photocurrent test system.

[0070] The camera module 13 is used to monitor the spot size on the sample to optimize the size and position of the focused spot.

[0071] The sample stage 12 can be an electric two-dimensional translation stage, which can be connected to the processing module and move along the two-dimensional direction at a certain step length under the control of the processing module, so as to realize the movement of the two-dimensional plane of the sample and realize two-dimensional imaging. The minimum translation distance of the translation stage can be 200nm.

[0072] The processing module 15 can be connected to the sample stage 12 and the semiconductor sample 11 carried by the sample stage 12 to read the photocurrent signal generated by the semiconductor sample being irradiated by the laser beam on one hand, and to control the movement of the sample stage 12 on the other hand.

[0073] Optional, see Figure 1The optical path component may further include a chopper 6, which is located between the laser beam combiner and the laser beam expander. The chopper is used to chop and modulate the continuous laser beam passing through the laser beam combiner to obtain a pulsed laser beam.

[0074] In this case, the light beam generated by the first laser source will pass through the beam combiner 5 and the chopper 6 to the beam expander 7, and then pass through the second reflector 8 to the beam splitter 9, enter the microscope objective 10 and focus onto the surface of the semiconductor sample 11 placed on the electric two-dimensional translation stage 12.

[0075] The light beam generated by the second laser source enters the first optical axis through the first reflector 4 and the beam combiner 5, and then passes through the chopper 6 and the beam expander 7, is reflected by the second reflector 8, enters the beam splitter 9, and then is incident on the microscope objective 10 to irradiate the semiconductor sample 11.

[0076] The chopper 6 is used to perform chopper modulation on the light beams generated by the first laser source 1 and the second laser source 3 so that the continuous light signal is converted into a pulse signal, so as to improve the sensitivity and accuracy of signal detection.

[0077] See also Figure 1 , the device of this embodiment may further include a lock-in amplifier 14, the lock-in amplifier is connected to the chopper;

[0078] Furthermore, the processing module is connected to the semiconductor sample via a lock-in amplifier.

[0079] The lock-in amplifier is used for amplifying the target frequency signals in the photocurrent signal and the diffused photocurrent signal generated by the semiconductor sample according to the target frequency output by the chopper.

[0080] Specifically, the chopper 6 can provide a target frequency for reference by the phase-locked amplifier 14. After receiving the current signal generated by the semiconductor sample, the phase-locked amplifier can amplify the signal at the target frequency and shield the noise signals at other frequencies, so as to improve the accuracy of the data obtained by the processing module.

[0081] Optionally, the wavelength of the second laser beam generated by the continuous laser light source is any one of 1064 nm, 852 nm, 532 nm and 405 nm. The specific wavelength of the laser beam generated can be controlled by the processing module according to the user's configuration or a specific control strategy.

[0082] As mentioned above, the processing module can control the sample stage to move at a certain step length to achieve two-dimensional imaging of the semiconductor sample carried by the sample stage. Furthermore, the processing module can also be used to configure different scanning step lengths for different areas of the semiconductor sample. Thus, depending on the current scanning area, the processing module can control the movement of the sample stage according to the scanning step length corresponding to the area.

[0083] Exemplarily, the scanning step length of area A of the semiconductor sample can be 200 nanometers (nm), and the scanning step length of area B can be 260nm. When the light spot is located in area A of the semiconductor sample, the processing module can control the movement of the sample stage at a scanning step length of 200nm. When the light spot is located in area B of the semiconductor sample, the processing module can control the movement of the sample stage at a scanning step length of 260nm.

[0084] In the device of this embodiment, after the supercontinuum laser 1 is started, the first laser beam generated passes through the laser beam combiner 5, the chopper 6, and the beam expander 7, and then is reflected to the beam splitter 9 by the reflector 8, and then passes through the microscope objective lens to hit the semiconductor sample 11 placed on the sample stage 12.

[0085] The optical path of the first laser beam passing through the beam combiner 5, chopper 6, and beam expander 7 is recorded as the first optical axis, and the optical path of the first laser beam reflected from the reflector 8 to the beam splitter 9, and then passing through the microscope objective lens to hit the semiconductor sample 11 placed on the sample stage 12 is recorded as the second optical axis.

[0086] The light beam generated by the continuous laser light source enters the first optical axis after passing through the reflector 4 and the laser beam combiner 5, and then irradiates the surface of the detection sample 11 along the same optical path as the light beam of the supercontinuum laser light source, which is used to characterize the regulation of light by the photocurrent diffusion area. The right end of the second optical axis is split by the beam splitter 9 to the right end and irradiates into the camera module 13, and the optical path from the beam splitter to the camera module can be recorded as the third optical axis.

[0087] The continuous laser light source 3 generally emits invisible light with wavelengths of 1064nm and 852nm. Therefore, before using the device of this embodiment to detect semiconductor samples, a dedicated color display card can be used to modulate the optical path; before building the subsequent optical path, the optical path must be collimated so that the laser emitted by the laser becomes parallel light, and then the light spot formed by the laser on the semiconductor sample is expanded by the beam expander 7. The process of modulating the optical path to achieve optical path collimation can be called the process of modulating the optical path component. The specific modulation method can be referred to the relevant prior art, which will not be repeated in this embodiment.

[0088] Combine the following Figure 2 The working principle of the device of this embodiment is described. Figure 2 A workflow diagram for characterizing a photocurrent diffusion microscopic imaging device for a photodetector is provided in an embodiment of the present application. The workflow may include the following steps.

[0089] S1. Start the first laser source.

[0090] S2. Provide a pulse light signal through a chopper.

[0091] S3. Modulate the optical path components to illuminate the light spot on the semiconductor sample.

[0092] S4. Adjust the sample stage according to the scanning step length.

[0093] S5. Monitor the light spot position through the camera module to determine the diffuse photocurrent area.

[0094] S6, collecting the photocurrent signal through a phase-locked amplifier to obtain a photocurrent distribution diagram.

[0095] S7, turn on the second laser source.

[0096] S8. Compare the photocurrent distribution diagrams before and after turning on the second laser source to obtain comparative information of the semiconductor sample.

[0097] In steps S1 and S2, the processing module can start the supercontinuum laser light source control power supply to excite the supercontinuum laser to generate a first laser beam, and simultaneously start the chopper to convert the continuous first laser beam into a pulse signal.

[0098] Then in step S3, the optical path component may be modulated according to the aforementioned process of modulating the optical path component to obtain a light spot irradiated on the semiconductor sample.

[0099] After the supercontinuum laser light source 1 passes through the laser beam combiner 5 and the chopper 6 to form a pulse light, it passes through the beam expander 7, the second reflector 8 to the beam splitter 9, and enters the microscope objective 10 to focus on the surface of the semiconductor sample 11. At this time, the processing module can move the sample stage in a two-dimensional plane according to a certain scanning step in step S4, so that the light spot scans the surface of the semiconductor sample, and receives the photocurrent signal generated when the semiconductor sample is irradiated by the light spot through the phase-locked amplifier. At the same time, the processing module can monitor the light spot position through the camera module in S5, and determine the diffuse photocurrent area of ​​the semiconductor sample in combination with the photocurrent signal and the light spot position.

[0100] Specifically, when the laser beam irradiates the PN junction interface of the semiconductor sample, the semiconductor sample will generate a photocurrent. When the irradiation point (light spot) is within a diffusion length from the depletion region, the semiconductor sample will also generate a photocurrent signal. Based on this, the processing module can control the movement of the sample stage so that the light spot is irradiated to different positions on the surface of the semiconductor sample, and obtain the photocurrent signal generated at each position when the light spot is irradiated through a phase-locked amplifier. Based on these signals, it is determined in real time whether the current position of the light spot is within the diffuse photocurrent region of the semiconductor sample, and then the position of the light spot on the semiconductor surface is determined in combination with the image taken by the camera module. In this way, it is possible to determine which positions on the surface of the semiconductor sample belong to the diffuse photocurrent region and which positions do not belong to the diffuse photocurrent region, thereby determining the diffuse photocurrent region.

[0101] Different semiconductor samples may have different depletion regions and diffusion lengths, and the depletion region and diffusion length may be inherent parameters of the semiconductor sample detected in advance by other detection methods.

[0102] Optionally, before step S6, a continuous laser light source 3 can be used to pass through a first reflector 4 into a laser beam combiner 5, then through a chopper 6 and a beam expander 7, and then reflected by a second reflector 8 into a beam splitter 9, and then into a microscope objective 10 to be focused and irradiated onto a sample 11, and a camera module 13 is used to determine the diffusion current region irradiated thereto.

[0103] In step S6, the processing module can use a supercontinuum laser to scan the diffuse photocurrent region of the sample 11. After the scanning is completed, the diffuse photocurrent signal of the diffuse photocurrent region of the sample 11 is obtained. These signals are transmitted to the processing module 15 after noise reduction processing by the phase-locked amplifier 14. The processing module 15 processes the obtained diffuse photocurrent signal to obtain a photocurrent distribution diagram of the diffuse photocurrent region of the semiconductor sample 11.

[0104] In step S7, the processing module can turn on the continuous laser light source so that the laser generated by the continuous laser light source and the laser generated by the supercontinuum laser simultaneously scan the diffuse photocurrent area on the surface of the semiconductor sample. After the scanning is completed, the diffuse photocurrent signal of the diffuse photocurrent area of ​​the sample 11 is obtained. These signals are transmitted to the processing module 15 after noise reduction processing by the phase-locked amplifier 14. The processing module 15 processes the obtained diffuse photocurrent signal to obtain a photocurrent distribution diagram of the diffuse photocurrent area of ​​the semiconductor sample 11.

[0105] The method of obtaining the photocurrent distribution diagram of the corresponding diffuse photocurrent area according to the diffuse photocurrent signal can be referred to the relevant prior art and will not be described in detail.

[0106] In step S8, the photocurrent distribution diagram of the diffuse photocurrent area obtained before turning on the continuous laser light source can be recorded as the first photocurrent distribution information, and the photocurrent distribution diagram of the diffuse photocurrent area obtained after turning on the continuous laser light source can be recorded as the second photocurrent distribution information. The processing module can compare the intensity of the diffuse photocurrent signal at the same position in the first photocurrent distribution information and the second photocurrent distribution information, and use the intensity difference obtained at each position as comparison information of the semiconductor sample.

[0107] Optionally, the intensity differences obtained at each position can be used to generate a corresponding image in the form of software drawing, where the pixels in the image correspond to each position on the surface of the semiconductor sample, and the grayscale value of each pixel is related to the difference in photocurrent signal intensity before and after the continuous laser light source is turned on at the corresponding position on the surface of the semiconductor sample.

[0108] This contrast information can reveal the optoelectronic properties inside the semiconductor sample.

[0109] The present application also provides a method for characterizing the diffusion of photocurrent in a photodetector by microscopic imaging. Figure 3 , the method may include the following steps.

[0110] S301, determining a diffusion photocurrent region of a semiconductor sample according to a photocurrent signal when the semiconductor sample is irradiated by a first laser beam.

[0111] S302, using a camera module to control the first laser beam and the second laser beam to irradiate a diffuse photocurrent region of the semiconductor sample to obtain a diffuse photocurrent signal of the semiconductor sample.

[0112] S303, obtaining photocurrent distribution information of the semiconductor sample according to the diffused photocurrent signal of the semiconductor sample.

[0113] Step S301 is equivalent to steps S1 to S5 of the aforementioned embodiment.

[0114] Steps S302 and S303 are equivalent to steps S6 and S7 of the aforementioned embodiment.

[0115] Optionally, using a camera module to control the first laser beam and the second laser beam to irradiate a diffusion photocurrent region of the semiconductor sample to obtain a diffusion photocurrent signal of the semiconductor sample, including:

[0116] Using a camera module to control a first laser beam to irradiate a diffusion photocurrent region of the semiconductor sample to obtain a first diffusion photocurrent signal of the semiconductor sample;

[0117] Using a camera module to control the first laser beam and the second laser beam to simultaneously irradiate the diffusion photocurrent region of the semiconductor sample to obtain a second diffusion photocurrent signal of the semiconductor sample;

[0118] The photocurrent distribution information of the semiconductor sample is obtained according to the diffuse photocurrent signal of the semiconductor sample, including:

[0119] Obtaining first photocurrent distribution information of the semiconductor sample according to a first diffuse photocurrent signal of the semiconductor sample;

[0120] Second photocurrent distribution information of the semiconductor sample is obtained according to the second diffusion photocurrent signal of the semiconductor sample.

[0121] The first photocurrent distribution information is equivalent to the photocurrent distribution diagram obtained by irradiating the diffuse photocurrent region of the semiconductor sample with only the supercontinuum laser before turning on the continuous laser light source. The second photocurrent distribution information is equivalent to the photocurrent distribution diagram obtained by irradiating the diffuse photocurrent region of the semiconductor sample with the continuous laser light source and the supercontinuum laser at the same time after turning on the continuous laser light source.

[0122] Optionally, also include:

[0123] Comparative information characterizing the photoelectric characteristics inside the semiconductor sample is obtained according to the first photocurrent distribution information and the second photocurrent distribution information.

[0124] The specific implementation method of this step can refer to step S8 of the above embodiment and will not be described in detail.

[0125] The specific implementation method of the method for characterizing the photocurrent diffusion microscopy of a photodetector in this embodiment can be found in the working principle of the device for characterizing the photocurrent diffusion microscopy of a photodetector provided in the embodiment of the present application, which will not be described in detail.

[0126] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0127] For the convenience of description, the above system or device is described by dividing it into various modules or units according to its functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0128] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0129] Finally, it should be noted that, in this article, relational terms such as first, second, third and fourth are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0130] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A microscopic imaging device for characterizing the diffusion of photocurrent of a photodetector, characterized in that: include: A first laser source, a second laser source, an optical path component, a sample stage, a camera module and a processing module; The first laser source is used to generate a first laser beam that is irradiated to the semiconductor sample carried by the sample stage through the optical path component; The second laser source is used to generate a second laser beam that passes through the optical path component and irradiates the semiconductor sample carried by the sample stage; The camera module is used to photograph the surface of the semiconductor sample carried by the sample stage; The processing module is connected to the semiconductor sample; The processing module is used for: determining a diffusion photocurrent region of the semiconductor sample according to a photocurrent signal when the semiconductor sample is irradiated by a first laser beam; Using the camera module to control the first laser beam and the second laser beam to irradiate the diffuse photocurrent region of the semiconductor sample to obtain a diffuse photocurrent signal of the semiconductor sample; Photocurrent distribution information of the semiconductor sample is obtained according to the diffuse photocurrent signal of the semiconductor sample.

2. The device according to claim 1, characterized in that The optical path assembly includes a first reflector, a laser beam combiner, a laser beam expander, a second reflector, a beam splitter and a microscope objective lens; The first laser beam is irradiated to the semiconductor sample carried by the sample stage through the optical path component, including: The first laser beam passes through the laser beam combiner, the laser beam expander, the second reflector, the beam splitter and the microscope objective lens in sequence, and irradiates the semiconductor sample carried by the sample stage; The second laser beam is irradiated to the semiconductor sample carried by the sample stage through the optical path component, including: After being reflected by the first reflector, the second laser beam passes through the laser beam combiner, the laser beam expander, the second reflector, the beam splitter and the microscope objective lens in sequence, and irradiates the semiconductor sample carried by the sample stage.

3. The device according to claim 2, characterized in that The optical path component also includes a chopper, which is located between the laser beam combiner and the laser beam expander. The chopper is used to chop and modulate the continuous laser beam passing through the laser beam combiner to obtain a pulsed laser beam.

4. The device according to claim 3, characterized in that It also includes a lock-in amplifier, which is connected to the chopper; The processing module is connected to the semiconductor sample via the lock-in amplifier; The lock-in amplifier is used to amplify the target frequency signal in the photocurrent signal and the diffused photocurrent signal generated by the semiconductor sample according to the target frequency output by the chopper.

5. The device according to claim 1, characterized in that The first laser source includes a supercontinuum laser and a supercontinuum laser light source control power supply, and the second laser source includes a continuous laser light source.

6. The device according to claim 5, characterized in that The wavelength of the second laser beam generated by the continuous laser light source is any one of 1064 nm, 852 nm, 532 nm and 405 nm.

7. The device according to claim 1, characterized in that The processing module is also used for: Different scanning step lengths are configured for different areas of the semiconductor sample.

8. A method for characterizing the diffusion of photocurrent in a photodetector by microscopic imaging, characterized in that: include: determining a diffusion photocurrent region of the semiconductor sample according to a photocurrent signal when the semiconductor sample is irradiated by a first laser beam; Using a camera module to control the first laser beam and the second laser beam to irradiate the diffuse photocurrent region of the semiconductor sample to obtain a diffuse photocurrent signal of the semiconductor sample; Photocurrent distribution information of the semiconductor sample is obtained according to the diffuse photocurrent signal of the semiconductor sample.

9. The method according to claim 8, characterized in that The method of using a camera module to control the first laser beam and the second laser beam to irradiate the diffuse photocurrent region of the semiconductor sample to obtain a diffuse photocurrent signal of the semiconductor sample includes: Using a camera module to control the first laser beam to irradiate the diffuse photocurrent region of the semiconductor sample to obtain a first diffuse photocurrent signal of the semiconductor sample; Using a camera module to control the first laser beam and the second laser beam to simultaneously irradiate the diffusion photocurrent region of the semiconductor sample to obtain a second diffusion photocurrent signal of the semiconductor sample; The step of obtaining the photocurrent distribution information of the semiconductor sample according to the diffused photocurrent signal of the semiconductor sample comprises: Obtaining first photocurrent distribution information of the semiconductor sample according to a first diffuse photocurrent signal of the semiconductor sample; Second photocurrent distribution information of the semiconductor sample is obtained according to the second diffused photocurrent signal of the semiconductor sample.

10. The method according to claim 9, characterized in that Also includes: Comparative information characterizing the photoelectric characteristics inside the semiconductor sample is obtained based on the first photocurrent distribution information and the second photocurrent distribution information.

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