Multi-channel Poly-Si film thickness tester based on solar thin film cell

Abstract

The utility model discloses a multi-channel Poly-Si film thickness tester based on a solar thin film cell. The multi-channel Poly-Si film thickness tester comprises a main shell and a bracket, a voltage-stabilized power supply, an LED light source, a transmission optical fiber and a spectrograph are arranged in the main shell; the LED light source is connected with the transmission optical fiber; the transmission optical fiber comprises a main optical fiber, an auxiliary optical fiber and a branch optical fiber, the main optical fiber is connected with the LED light source, and the auxiliary optical fiber comprises a plurality of incident light cores and a reflection light core; the reflection optical core is connected with the spectrograph through a branch optical fiber; the incident optical core transmits an optical signal to a tested sample, and the optical signal reflected by the tested sample is collected by the reflective optical core and transmitted to the spectrograph through the branch optical fiber; a calibration platform is arranged on the main shell, and an incident light hole is formed in the calibration platform; and the calibration platform is also provided with a reflector. According to the utility model, multi-channel high-efficiency measurement can be realized, high test convenience and high efficiency are realized, calibration and test integration is realized, and high accuracy and stability of test data points are ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of solar thin-film battery film thickness testing, in particular to a multi-channel Poly-Si film thickness tester based on solar thin-film batteries. Background Art

[0002] Improving the efficiency of crystalline silicon solar cells is an eternal topic. The Fraunhofer Institute in Germany first mentioned the concept of tunneling oxide passivation contact (TOPCon) at the 28th European Energy and Photovoltaic Solar Energy Exhibition (EU-PVSEC) in 2013. The purpose is to improve the passivation of the back surface of crystalline silicon cells. Compared with the previous PERC process, the efficiency of TOPCon technology can exceed 26%. In terms of the specific process of TOPCon cells, firstly, a layer of ultra-thin silicon oxide (i.e., tunneling oxide layer) less than 1.5nm is grown on the back of the cell using a wet chemical method; the tunneling oxide layer can eliminate the dangling bonds on the surface of crystalline silicon and play a role in chemical passivation. Then a layer of phosphorus-doped amorphous silicon of about 30nm is deposited. After high-temperature heat treatment, the amorphous silicon is transformed into polycrystalline silicon, and the doped phosphorus atoms are activated; due to the different doping levels of polycrystalline silicon and crystalline silicon substrates, that is, the different Fermi levels, the energy band will bend, which can achieve a field passivation effect, effectively prevent minority carriers from reaching the interface, and effectively collect majority carriers. Related studies have shown that as the thickness of the Poly-Si (polycrystalline silicon) layer increases, the passivation effect will be improved, that is, the open circuit voltage will first increase and then tend to saturation. At the same time, free carrier absorption will also increase, thereby reducing Jsc (short circuit current density), so the efficiency will first increase and then decrease with the thickness. Therefore, monitoring the thickness of the Poly-Si layer is a key link in improving the photoelectric conversion efficiency of the cell.

[0003] Nowadays, the methods of measuring film thickness are mainly divided into two categories: contact type and non-contact type. Among them, the contact type measuring instrument is mainly a step meter, which is characterized by high test accuracy. Its disadvantage is that it has special requirements for the sample to be measured, requires special sample preparation, and cannot realize online testing. Non-contact measuring instruments are mainly ellipsometers and reflective film thickness measuring instruments. There are differences in the testing principles of the two. The ellipsometer uses the elliptical polarization method (polarization method) to analyze the film thickness and optical constants of the film according to the change of the polarization state of light. The film thickness, refractive index and extinction coefficient of the sample can be tested. The reflective film thickness measuring instrument uses the principle of optical interference to analyze the reflection spectrum formed by the interference of the reflected light on the surface of the film and the reflected light at the interface between the film and the substrate, and quickly and accurately measures the film thickness, optical constants and other information. Compared with the ellipsometer, the reflective measuring instrument can be perfectly coupled with the TOPCon production line due to its structural advantages, and finally realize high-precision and high-efficiency online testing.

[0004] The existing reflective film thickness measuring instrument needs to be calibrated before testing, and the calibration operation is inconvenient. In addition, the testing convenience, automation and integration level need to be improved, and the accuracy and stability of the test data points also need to be improved. Utility Model Content

[0005] In order to solve the above technical problems, the purpose of the utility model is to provide a multi-channel Poly-Si film thickness tester based on solar thin-film cells, which has a high degree of integration and automation, can realize high-efficiency measurement of multiple channels, has high testing convenience and efficiency, realizes the integration of calibration and testing, and also ensures high test data point accuracy and stability.

[0006] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0007] A multi-channel Poly-Si film thickness tester based on solar thin-film cells, comprising a main housing and a bracket mounted on the main housing; a voltage-stabilized power supply, an LED light source, a transmission optical fiber and a spectrometer are installed in the main housing;

[0008] The LED light source is connected to the transmission optical fiber; the transmission optical fiber includes a main optical fiber, a secondary optical fiber and a branch optical fiber, the outer end of the main optical fiber is connected to the LED light source, and a plurality of secondary optical fibers are provided, each of which includes a plurality of incident optical cores and a reflection optical core; the reflection optical core is connected to the spectrometer through a branch optical fiber; the incident optical core transmits the optical signal to the surface of the sample to be measured, and the optical signal reflected by the sample to be measured is collected by the reflection optical core and transmitted to the spectrometer through the branch optical fiber;

[0009] The main shell is provided with a calibration platform, and the calibration platform is provided with an incident light hole for the optical signal to pass through; the calibration platform is also provided with a reflector; the calibration platform can move the reflector to place the reflector on the optical signal transmission path to perform light source calibration.

[0010] Furthermore, a solid-state relay is installed in the main housing.

[0011] Furthermore, a photoelectric sensor is also provided in the main housing, and the photoelectric sensor is connected to the solid-state relay.

[0012] Furthermore, the output wavelength of the LED light source is 320-1100 nm.

[0013] Furthermore, the number of the auxiliary optical fibers is set to 5, each of which includes 6 incident optical cores and 1 reflected optical core, and the reflected optical core is located at the center of the auxiliary optical fiber.

[0014] Furthermore, the calibration platform is provided with five reflectors corresponding to the five secondary optical fibers.

[0015] Furthermore, the spectrometer is connected to a HUB hub, and the HUB hub is connected to an external computer.

[0016] Furthermore, a slide rail is installed on the main shell, a slider is installed on the calibration platform, the calibration platform is slidably installed on the slide rail through the slider, a driving mechanism is installed in the main shell, and the driving mechanism is connected to the calibration platform to drive the calibration platform to move.

[0017] Furthermore, the film thickness tester is placed across the battery cell production line via the bracket.

[0018] The beneficial effects of the utility model are:

[0019] The utility model is based on the principle of optical interference. By analyzing the reflection spectrum formed by the interference of the reflected light on the surface of the film and the reflected light at the interface between the film and the substrate, the utility model can quickly and accurately measure information such as the thickness of the film, thereby avoiding the shortcomings of the contact-type film thickness measuring instrument, such as low efficiency and easy damage to the tested sample.

[0020] The film thickness tester of the utility model can cooperate with the production line to realize online testing. It can directly test without specific mathematical modeling of the Poly-Si layer. The overall testing convenience and automation level are much higher than the same type of non-contact film thickness testing equipment.

[0021] The utility model has a reflector for optical calibration, and the calibration and test switching can be realized by simply moving the calibration platform axially, thus realizing the integration of calibration and test and ensuring the accuracy and stability of the test data points;

[0022] During testing, the incident light can be vertically irradiated to the Poly-Si film layer through optical fiber transmission, and the distance between the instrument and the sample to be tested can be fixed by a bracket, which can effectively avoid the influence of external light on the test.

[0023] The utility model can realize multi-channel testing, can realize global monitoring of the Poly-Si layer of the sample, and is beneficial to monitoring the uniformity of the film layer after the CVD process section. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of the overall structure of the multi-channel Poly-Si film thickness tester of the present utility model.

[0025] Figure 2 This is a schematic structural diagram of the multi-channel Poly-Si film thickness tester of the utility model from another perspective.

[0026] Figure 3 The figure is a schematic diagram of the internal structure of the multi-channel Poly-Si film thickness tester of the present utility model.

[0027] Figure 4 It is a structural schematic diagram of the calibration platform in the multi-channel Poly-Si film thickness tester of the utility model.

[0028] Figure 5 It is a schematic diagram of the structure of the transmission optical fiber in the multi-channel Poly-Si film thickness tester of the utility model.

[0029] Figure 6 It is a schematic diagram of the arrangement structure of the reflection optical core and the incident optical core in the auxiliary optical fiber of the present invention.

[0030] Figure 7 This is a schematic diagram of the cooperation between the multi-channel Poly-Si film thickness tester of the utility model and the battery cell production line.

[0031] In the figure, 1: main shell; 2: bracket; 3: voltage-stabilized power supply; 4: LED light source; 5: transmission optical fiber, 51: main optical fiber, 52: auxiliary optical fiber, 521: incident optical core, 522: reflection optical core, 53: branch optical fiber; 6: photoelectric sensor; 7: spectrometer; 8: solid-state relay; 9: HUB hub; 10: calibration platform, 1001: incident light hole; 11: reflector; 12: cylinder; 13: slider; 14: slide rail; 15: cooling fan. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0033] like Figures 1 to 6 A preferred embodiment of a multi-channel Poly-Si film thickness tester based on solar thin-film cells is shown, which includes a main shell 1 and a bracket 2 installed on the main shell 1; a voltage-stabilized power supply 3, an LED light source 4, a transmission optical fiber 5, a photoelectric sensor 6, a spectrometer 7 and a solid-state relay 8 are installed in the main shell 1.

[0034] The voltage-stabilized power supply 3 provides a constant current for the light source, spectrometer and other modules inside the instrument, ensuring the stability of the light source and the normal operation of other modules.

[0035] The solid-state relay 8 has the functions of short-circuit protection, overload protection and overheat protection. Through the set combination logic solidification package, the intelligent control of the optical path system can be realized.

[0036] The photoelectric sensor 6 is connected to the solid-state relay 8 to detect whether there is an empty cell (whether there is a missed cell).

[0037] The LED light source 4 is connected to the transmission optical fiber 5, and the LED light source 4 can stably and continuously output a stable light source with a wavelength of 320-1100nm; the main body of the transmission optical fiber 5 is 2750mm long, and it includes a main optical fiber 51, a secondary optical fiber 52 and a branch optical fiber 53, the outer end of the main optical fiber 51 is connected to the LED light source 4, and the secondary optical fibers 52 are provided with 5; the 5 secondary optical fibers 52 are connected to the 5 interfaces of the bottom plate of the main housing 1 through a connector; each secondary optical fiber 52 includes 5 incident light cores 521 and 1 A reflective optical core 522 is provided, and the reflective optical core 522 is located at the center of the auxiliary optical fiber 52; the reflective optical core 522 is connected to the spectrometer 7 through a branch optical fiber 53; the incident optical core 521 transmits the optical signal to the surface of the sample to be tested, and the optical signal reflected by the sample to be tested is collected by the reflective optical core 522, transmitted to the branch optical fiber 53, and transmitted to the spectrometer 7 through the branch optical fiber 53; the spectrometer 7 is connected to the HUB hub 9, and the HUB hub 9 is connected to an external computer to form an optical signal data analysis module. In this embodiment, there are 5 spectrometers 7.

[0038] The main shell 1 is provided with a calibration platform 10, and the calibration platform 10 is provided with an incident light hole 1001 for the optical signal to pass through; corresponding to the five auxiliary optical fibers 52, the calibration platform 10 is provided with five incident light holes 1001; five reflectors 11 are also installed on the calibration platform 10; each reflector 11 is respectively close to the position of the incident light hole 1001; the calibration platform 10 can move the reflector 11 to place the optical signal transmission path to calibrate the light source.

[0039] The five incident light holes 1001 correspond to the upper left corner, upper right corner, lower left corner, lower right corner and geometric center of the sample under test, respectively, so as to realize global monitoring of the Poly-Si layer of the sample under test.

[0040] The movement of the calibration platform 10 is driven by a driving mechanism installed in the main shell 1; specifically, a slide rail 14 is installed on the main shell 1, and a slider 13 is installed on the calibration platform 10. The calibration platform 10 is slidably installed on the slide rail 14 through the slider 13, and the driving mechanism is connected to the calibration platform 10; in this embodiment, the driving mechanism is a cylinder 12, and the cylinder 12 drives the calibration platform 10 to move with the cooperation of the slide rail 14 and the slider 13.

[0041] The main housing 1 of the film thickness tester is provided with brackets 2 on both sides, and the brackets 2 are trapezoidal brackets; the film thickness tester is placed across the battery cell production line through the brackets 2. Specifically, the brackets are fixedly connected to the screw holes reserved at the base of the battery cell production line, ensuring that the incident light irradiates the sample to be tested vertically while ensuring the overall stability of the instrument in actual application.

[0042] The main housing 1 is also provided with a cooling fan 15 for cooling the instrument.

[0043] The dimensions of the film thickness tester of the utility model are: 385 mm in length, 284.7 mm in top width, 351 mm in bottom width, and 519.2 mm in total height.

[0044] The utility model is a multi-channel poly-Si film thickness tester, which is mainly used for detecting the thickness of the Poly-Si film layer of the battery cell after CVD coating in the TOPCon process; the film thickness tester is straddled above the battery cell production line through a bracket 2, and its outside is connected to the automatic power supply, and the instrument test instruction is triggered by the automatic signal. During the test, firstly, the internal LED light source 4 is powered by the internal voltage-stabilized power supply 3 of the instrument, and the LED light source 4 is connected to the "one-to-five" transmission optical fiber 5, and the five auxiliary optical fibers 52 are respectively connected to the bottom of the instrument (the bottom of the main shell) The five interfaces are connected, and the light source first irradiates the reflector 11 through the incident light hole 1001 of the calibration platform 10 for calibration. After calibration, the software controls the calibration platform 10 to move under the drive of the cylinder 12, and the reflector 11 is removed. The light source can directly irradiate the battery cell of the production line. The light is irradiated to the silicon substrate through the Poly-Si layer of the battery cell and then reflected. The reflected light is received by the reflective optical core 522. The optical fiber transmits the reflected interference light to the five internal spectrometers 7 for analysis. Finally, the analysis signal is integrated and transmitted to the external computer through the HUB hub 9.

[0045] The utility model applies the principle of optical interference to the Poly-Si film thickness test in the TOPCon battery process, arranges the light source module, the test module, the data analysis module and the motion module in a structural layout, and realizes a simple integrated test instrument.

[0046] The optical fiber structure of the utility model is unique, and adopts a one-to-five structural design to achieve high-efficiency measurement of multiple channels.

[0047] The optical fiber and the spectrometer of the utility model are connected one by one in a 5-5 form, and a hub is used to aggregate digital information to a data analysis computer. This data testing, analysis and processing process is convenient and efficient.

[0048] The utility model realizes the connection between the instrument and the production line and at the same time has a light source calibration module (calibration platform and reflector), thus realizing high automation of the instrument.

[0049] The utility model adopts LED spectrum light source, which ensures light intensity and life while improving test compatibility.

[0050] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0051] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A multi-channel Poly-Si film thickness tester based on solar thin film cells, characterized in that: It includes a main housing and a bracket installed on the main housing; a voltage-stabilized power supply, an LED light source, a transmission optical fiber and a spectrometer are installed in the main housing; The LED light source is connected to the transmission optical fiber; the transmission optical fiber includes a main optical fiber, a secondary optical fiber and a branch optical fiber, the outer end of the main optical fiber is connected to the LED light source, and a plurality of secondary optical fibers are provided, each of which includes a plurality of incident optical cores and a reflection optical core; the reflection optical core is connected to the spectrometer through a branch optical fiber; the incident optical core transmits the optical signal to the surface of the sample to be measured, and the optical signal reflected by the sample to be measured is collected by the reflection optical core and transmitted to the spectrometer through the branch optical fiber; The main shell is provided with a calibration platform, and the calibration platform is provided with an incident light hole for the optical signal to pass through; the calibration platform is also provided with a reflector; the calibration platform can move the reflector to place the reflector on the optical signal transmission path to perform light source calibration.

2. A multi-channel Poly-Si film thickness tester based on solar thin film cells according to claim 1, characterized in that: A solid-state relay is also installed in the main housing.

3. A multi-channel Poly-Si film thickness tester based on solar thin film cells according to claim 2, characterized in that: A photoelectric sensor is also provided in the main housing, and the photoelectric sensor is connected to the solid-state relay.

4. A multi-channel Poly-Si film thickness tester based on solar thin film cells according to claim 1, characterized in that: The output wavelength of the LED light source is 320-1100nm.

5. A multi-channel Poly-Si film thickness tester based on solar thin film cells according to claim 1, characterized in that: The number of the auxiliary optical fibers is 5, and each auxiliary optical fiber includes 6 incident optical cores and 1 reflection optical core, and the reflection optical core is located at the center of the auxiliary optical fiber.

6. A multi-channel Poly-Si film thickness tester based on solar thin film cells according to claim 5, characterized in that: The calibration platform is provided with five reflectors corresponding to the five secondary optical fibers.

7. A multi-channel Poly-Si film thickness tester based on solar thin film cells according to claim 1, characterized in that: The spectrometer is connected to a HUB hub, and the HUB hub is connected to an external computer.

8. The multi-channel Poly-Si film thickness tester based on solar thin film cells according to claim 1, characterized in that: A slide rail is installed on the main shell, a slider is installed on the calibration platform, the calibration platform is slidably installed on the slide rail through the slider, a driving mechanism is installed in the main shell, and the driving mechanism is connected to the calibration platform to drive the calibration platform to move.

9. A multi-channel Poly-Si film thickness tester based on solar thin film cells according to claim 1, characterized in that: The film thickness tester is placed across the battery cell production line via the bracket.

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