A detector cross-sectional light response distribution detection method and system

Abstract

The present application discloses a detector cross-sectional photoresponse distribution detection method and system, which relates to the field of detector measurement. The method comprises: preparing a dissociation surface of the detector by a dissociation process; and detecting the photocurrent distribution characteristics of the dissociation surface of the detector by a photoinduced current technique to determine the photoresponse distribution of the detector cross section. The present application does not introduce an additional leakage channel after the detector is dissociated, and while fully exposing the functional structure of the detector, ensures that the detector can work normally, and can extract the photocurrent distribution characteristics of its cross section when the detector is in working state.

Description

Technical Field

[0001] The present application relates to the field of detector measurement, and in particular to a method and system for detecting the distribution of light response of a detector cross section. Background Art

[0002] In the process of photodetector research and development, the measurement of photodetectors is an indispensable part, such as dark current, response rate, spectral response detection, etc. However, so far, the information extracted by these measurement methods is difficult to directly feedback the deviation of the device structure and process implementation effect. In particular, considering that the light absorption and charge carrier collection of photodetectors are both in the depth direction, due to being far away from the surface (1μm~5μm below the surface), their spatial distribution information and the resulting impact on efficiency are difficult to directly extract experimentally, which to a certain extent limits the evaluation and optimization of photodetectors.

[0003] Related extreme spatial resolution measurement technologies, such as transmission electron microscopy, scanning tunneling microscopy, and three-dimensional atom probes, can achieve atomic-scale resolution on any cross section, and play an irreplaceable role in characterizing microstructure properties. However, these analytical methods are difficult to obtain electronic information directly related to the performance of photodetectors, such as free electrons and holes, and electric field distribution, and thus cannot meet the functional diagnosis and evaluation needs of photodetectors.

[0004] Some measurement technologies with both spatial and electronic resolution capabilities, such as scanning differential capacitance, scanning parasitic resistance, scanning electromagnetic impedance methods, etc., can distinguish the distribution and transport characteristics of charge carriers on any cross section, and have been widely used in the detection and development of photodetectors. However, these methods are all contact-based, and the measurement itself will destroy the working state of the photodetector and even introduce damage, so they are usually used to analyze the static behavior of photodetectors. Summary of the invention

[0005] The purpose of the present application is to provide a method and system for detecting the light response distribution of a detector cross section, which can extract the distribution characteristics of the photogenerated current in the cross section of the detector when the detector is in working state.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] In a first aspect, the present application provides a method for detecting a detector cross-sectional light response distribution, comprising:

[0008] A dissociation surface of the detector is prepared by using a dissociation process;

[0009] The photoinduced current technology is used to detect the photocurrent distribution characteristics of the dissociation surface of the detector to determine the photoresponse distribution of the detector cross section.

[0010] Optionally, the dissociation plane passes through a photosensitive element region of the detector.

[0011] Optionally, the dissociation plane passes through the center of the photosensitive element area of ​​the detector, so that the detector is divided into two semicircular structures.

[0012] Optionally, when a dissociation surface of the detector is prepared by a dissociation process, the dissociation is aligned with the cracking crystal direction so that the flatness of the dissociation surface of the detector reaches the atomic level.

[0013] Optionally, the detector cross-sectional light response distribution detection method further includes: fixing the detector on a circuit board by epoxy resin glue so that the dissociation surface of the detector is flush with the horizontal plane, and bonding the electrodes of the detector to the circuit board.

[0014] Optionally, a photoinduced current technique is used to detect the photogenerated current distribution characteristics of the dissociation surface of the detector, specifically including: using an excitation light source to scan the dissociation surface of the detector, and recording the photogenerated current signal at each spatial position of the dissociation surface of the detector through a cross-sectional photocurrent testing device to obtain the photogenerated current distribution characteristics.

[0015] Optionally, the cross-sectional photocurrent testing device comprises: a chopper, a first galvanometer, a second galvanometer, a lens and a phase-locked amplifier; the chopper, the first galvanometer, the second galvanometer and the lens are sequentially arranged on the optical path of the excitation light source; the phase-locked amplifier is respectively connected to the electrodes of the chopper and the detector;

[0016] The photocurrent signal at each spatial position of the detector's dissociation surface is recorded by a cross-sectional photocurrent test device, specifically including:

[0017] Modulating the excitation light source into a pulse light excitation signal by the chopper;

[0018] Controlling the pulse light excitation signal to move stepwise in two orthogonal directions through the first galvanometer and the second galvanometer, and focusing the pulse light excitation signal on the dissociation surface of the detector through the lens;

[0019] The current characteristic of the detector is read by the phase-locked amplifier, and the photocurrent signal of the detector is determined according to the reference frequency signal of the chopper and the current characteristic.

[0020] Optionally, the detector is a photodetector.

[0021] Optionally, the detector cross-sectional light response distribution detection method further comprises: drawing a two-dimensional photogenerated current distribution image according to the photogenerated current distribution characteristics of the dissociation surface of the detector.

[0022] In a second aspect, the present application provides a detector cross-sectional light response distribution detection system, comprising:

[0023] A dissociation module, used for preparing a dissociation surface of the detector by using a dissociation process;

[0024] The testing module is used to detect the photocurrent distribution characteristics of the dissociation surface of the detector by using the photoinduced current technology to determine the photoresponse distribution of the detector cross section.

[0025] According to the specific embodiments provided in this application, this application has the following technical effects:

[0026] The present application provides a method and system for detecting the photoresponse distribution of a detector cross section, wherein a dissociation process is used to prepare a dissociation surface of the detector, and no additional leakage channels are introduced after the detector is dissociated. While the functional structure of the detector is fully exposed, the normal operation of the detector is ensured. The photoinduced current technology is further used to detect the photocurrent distribution characteristics of the dissociation surface of the detector, and the photocurrent distribution characteristics of its cross section can be extracted when the detector is in a working state. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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 will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic flow chart of a method for detecting the distribution of light response of a detector cross section provided in one embodiment of the present application.

[0029] Figure 2 This is a partial microscopic enlarged image of the detector after dissociation in one embodiment of the present application.

[0030] Figure 3 This is a volt-ampere characteristic curve of the detector dissociation surface in one embodiment of the present application.

[0031] Figure 4 Schematic diagram of a cross-sectional photocurrent testing device in one embodiment of the present application.

[0032] Figure 5 This is a two-dimensional photogenerated current distribution diagram obtained on the detector cross section in one embodiment of the present application.

[0033] Figure 6 A schematic diagram of a detector cross-sectional light response distribution detection system provided in one embodiment of the present application.

[0034] Explanation of the reference numerals: 201 - photosensitive element region, 202 - substrate, 203 - epitaxial functional layer, 204 - bonding point, 205 - P electrode, 206 - N electrode, 401 - excitation light source, 402 - chopper, 403 - first galvanometer, 404 - second galvanometer, 405 - lens, 406 - phase-locked amplifier, 407 - electrode of the photosensitive element region, 408 - bottom electrode, 601 - dissociation module, 602 - test module. DETAILED DESCRIPTION

[0035] 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.

[0036] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0037] In an exemplary embodiment, Figure 1 As shown, a method for detecting the distribution of light response of a detector cross section is provided, comprising the following steps 101 and 102.

[0038] Step 101, using a dissociation process to prepare a dissociation surface of a detector, wherein the detector is a photoelectric detector.

[0039] like Figure 2 As shown, the dissociation plane passes through the photosensitive element region 201 of the detector. Specifically, the dissociation plane passes through the center of the photosensitive element region 201 of the detector, so that the detector is divided into two semicircular structures. Figure 2 One of the semicircular structures is shown in Figure 2.

[0040] In a preferred embodiment, when the dissociation surface of the detector is prepared by a dissociation process, the dissociation is aligned with the cracking crystal direction so that the flatness of the dissociation surface of the detector reaches the atomic level. Figure 2 The lower right corner of the figure shows a microscope image of the dissociation surface. Since the cleavage crystal direction is strictly aligned during dissociation, the dissociation surface is sufficiently flat, and no obvious height fluctuation is observed under 1000 times magnification. The photosensitive element region 201 of the detector is a substrate 202 and an epitaxial functional layer 203 along the z-axis, and the electrodes of the photosensitive element region 201 include a P electrode 205 and an N electrode 206.

[0041] The present application uses a fine dissociation process to obtain a dissociation surface of the detector with atomic-level flatness, and ensures that the dissociation surface passes through the photosensitive element region 201 of the detector, exposing the cross section of the photosensitive element. The dissociation surface reaches atomic-level flatness, so that the detector does not degrade in performance due to additional lattice damage, and ensures that the dissociation surface has a complete PiN and other detection functional structures.

[0042] The dissociated detector is further spot welded and fixed to the circuit board. Specifically, the detector is turned over so that the dissociated surface of the detector is flush with the horizontal plane, the detector is fixed to the circuit board by epoxy resin glue, and the electrode of the detector is bonded to the circuit board through the bonding point 204. The detector is supported and fixed to the circuit board with epoxy resin glue and silicon wafer, and then the electrode of the detector is led to the designated port of the circuit board by bonding.

[0043] Since the dissociation surface has nanometer-level flatness, no additional leakage channels are introduced after the detector is dissociated, so it can work normally. Figure 3 The figure shows the volt-ampere characteristic curve of the detector after dissociation, which shows a rectification ratio of 6 orders of magnitude, indicating that the PiN junction of the detector works normally without obvious performance degradation.

[0044] Step 102: Use a photoinduced current technique to detect the photocurrent distribution characteristics of the dissociation surface of the detector to determine the photoresponse distribution of the detector cross section.

[0045] In an exemplary embodiment, an excitation light source is used to scan the dissociation surface of the detector, and a cross-sectional photocurrent testing device is used to record the photogenerated current signal at each spatial position of the dissociation surface of the detector to obtain the photogenerated current distribution characteristics.

[0046] The present application introduces an external laser beam to stimulate the dissociation surface of the detector and simultaneously records the photocurrent signal of the detector.

[0047] Among them, Figure 4 As shown, the cross-sectional photocurrent testing device includes: a chopper 402, a first galvanometer 403, a second galvanometer 404, a lens 405 and a phase-locked amplifier 406. The chopper 402, the first galvanometer 403, the second galvanometer 404 and the lens 405 are sequentially arranged on the optical path of the excitation light source 401. The phase-locked amplifier 406 is respectively connected to the chopper 402 and the electrodes of the detector. Specifically, the phase-locked amplifier 406 is respectively connected to the chopper 402, the electrode 407 of the photosensitive element region 201 of the detector and the bottom electrode 408 of the detector.

[0048] The excitation light source 401 is modulated into a pulse light excitation signal by the chopper 402. Specifically, the output of the excitation light source 401 and the detector is periodically modulated by the chopper 402.

[0049] The first galvanometer 403 and the second galvanometer 404 control the pulse light excitation signal to move stepwise in two orthogonal directions, and the lens 405 focuses the pulse light excitation signal on the dissociation surface of the detector.

[0050] Specifically, the laser spot scanning excitation detector's dissociation surface is precisely controlled by adjusting the rotation angles of the first galvanometer mirror 403 and the second galvanometer mirror 404 .

[0051] The current characteristics of the detector are read by the lock-in amplifier 406, and the photocurrent signal of the detector is determined according to the reference frequency signal and current characteristics of the chopper 402. Specifically, the lock-in amplifier 406 extracts the detector photocurrent signal with a high signal-to-noise ratio according to the reference frequency signal of the chopper 402.

[0052] The laser beam is focused by lens 405 to a diameter of ~1μm, and is controlled by two galvanometers to move in two orthogonal directions with a stepping accuracy of ~0.2μm. Based on the above steps, the laser spot scans the dissociation surface of the detector point by point. Where ~ represents an approximate value or approximately equal to.

[0053] Furthermore, a two-dimensional photogenerated current distribution image is drawn according to the photogenerated current distribution characteristics of the dissociation surface of the detector.

[0054] A laser beam is modulated into a pulsed light excitation signal by a chopper 402. The reference frequency signal of the chopper 402 is simultaneously provided to a phase-locked amplifier 406. The pulsed light excitation signal is controlled by two galvanometers to move in steps in two orthogonal directions (x-axis direction and z-axis direction). A lens 405 or a microscope objective is placed at the rear end of the galvanometer to constrain the spot diameter of the excitation light to ~1μm. The two electrodes of the detector are connected to the phase-locked amplifier 406. Based on this configuration, when the excitation light scans the dissociation surface of the detector, the detector generates a corresponding photocurrent signal and inputs it into the phase-locked amplifier 406. The phase-locked amplifier 406 mixes the input signal with the reference frequency signal of the chopper 402, and then selects a suitable modulation frequency to keep the original signal away from the noise background to obtain a true photocurrent signal. And as the light spot moves, the phase-locked amplifier 406 will read the current characteristic values ​​one by one, and finally draw a two-dimensional photocurrent distribution image of the cross section, such as Figure 5 shown.

[0055] While fully exposing the functional structure of the detector, the present application ensures that the detector can work normally. An optical probe method can be used to stimulate and record the photogenerated current signal at each spatial position, and then a two-dimensional photogenerated current distribution image of the detector cross section can be drawn. That is, the spatial distribution characteristics of the photogenerated current in the cross section of the detector can be extracted when the detector is in a working state. The information obtained will help to extract core information such as minority carrier diffusion length, evaluate active area width, pixel crosstalk, and promote the structural and process optimization of the detector.

[0056] Based on the same inventive concept, the embodiment of the present application also provides a detector cross-sectional light response distribution detection system for implementing the detector cross-sectional light response distribution detection method involved above. The implementation scheme for solving the problem provided by the system is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more detector cross-sectional light response distribution detection system embodiments provided below can refer to the limitations of the detector cross-sectional light response distribution detection method above, and will not be repeated here.

[0057] In an exemplary embodiment, Figure 6 As shown, a detector cross-sectional light response distribution detection system is provided, including: a dissociation module 601 and a testing module 602 .

[0058] The dissociation module 601 is used to prepare the dissociation surface of the detector by using a dissociation process.

[0059] The testing module 602 is used to detect the photocurrent distribution characteristics of the dissociation surface of the detector using the photoinduced current technology to determine the photoresponse distribution of the detector cross section.

[0060] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0061] In this application, all actions to obtain signals, information or data are carried out in compliance with the relevant data protection laws and policies of the country where they are located and with the authorization given by the owner of the corresponding device.

[0062] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0063] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0064] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A detector cross-sectional light response distribution detection method, characterized in that: The detector cross-sectional light response distribution detection method comprises: The dissociation surface of the detector is prepared by a dissociation process; the dissociation surface passes through the photosensitive element area of ​​the detector, so that the cross section of the photosensitive element is exposed; The photoinduced current technology is used to detect the photocurrent distribution characteristics of the dissociation surface of the detector to determine the photoresponse distribution of the detector cross section.

2. The detector cross-sectional light response distribution detection method according to claim 1, characterized in that: The dissociation plane passes through the center of the photosensitive element area of ​​the detector, so that the detector is divided into two semicircular structures.

3. The detector cross-sectional light response distribution detection method according to claim 1, characterized in that: When the dissociation surface of the detector is prepared by the dissociation process, the dissociation is aligned with the cracking crystal direction so that the flatness of the dissociation surface of the detector reaches the atomic level.

4. The detector cross-sectional light response distribution detection method according to claim 1, characterized in that: The detector cross-sectional light response distribution detection method further comprises: Fix the detector to the circuit board by epoxy glue, make the dissociated surface of the detector flush with the horizontal plane, and bond the electrodes of the detector to the circuit board.

5. The detector cross-sectional light response distribution detection method according to claim 1, characterized in that: The photoinduced current technology is used to detect the photogenerated current distribution characteristics of the dissociation surface of the detector, specifically including: The dissociation surface of the detector is scanned by an excitation light source, and the photocurrent signal at each spatial position of the dissociation surface of the detector is recorded by a cross-sectional photocurrent testing device to obtain the distribution characteristics of the photocurrent.

6. The detector cross-sectional light response distribution detection method according to claim 5, characterized in that: The cross-sectional photocurrent testing device comprises: a chopper, a first galvanometer, a second galvanometer, a lens and a phase-locked amplifier; the chopper, the first galvanometer, the second galvanometer and the lens are sequentially arranged on the optical path of the excitation light source; the phase-locked amplifier is respectively connected to the electrodes of the chopper and the detector; The photocurrent signal at each spatial position of the detector's dissociation surface is recorded by a cross-sectional photocurrent test device, specifically including: Modulating the excitation light source into a pulse light excitation signal by the chopper; Controlling the pulse light excitation signal to move stepwise in two orthogonal directions through the first galvanometer and the second galvanometer, and focusing the pulse light excitation signal on the dissociation surface of the detector through the lens; The current characteristic of the detector is read by the phase-locked amplifier, and the photocurrent signal of the detector is determined according to the reference frequency signal of the chopper and the current characteristic.

7. The detector cross-sectional light response distribution detection method according to claim 1, characterized in that: The detector is a photoelectric detector.

8. The detector cross-sectional light response distribution detection method according to claim 1, characterized in that: The detector cross-sectional light response distribution detection method further comprises: A two-dimensional photogenerated current distribution image is drawn according to the photogenerated current distribution characteristics of the dissociation surface of the detector.

9. A detector cross-sectional light response distribution detection system, applied to the detector cross-sectional light response distribution detection method according to any one of claims 1 to 8, characterized in that: The detector cross-sectional light response distribution detection system comprises: A dissociation module, used for preparing a dissociation surface of the detector by using a dissociation process; The testing module is used to detect the photocurrent distribution characteristics of the dissociation surface of the detector by using the photoinduced current technology to determine the photoresponse distribution of the detector cross section.

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