Semiconductor structure doping concentration distribution measurement system

Abstract

The invention relates to the technical field of optical measurement, and discloses a semiconductor structure doping concentration distribution measurement system comprising an excitation module used for generating excitation light; the light splitting module is located on a light path of the exciting light and used for splitting the exciting light into first power light and second power light, and the first power light is used for irradiating a sample to be detected; the measuring module is located on the light path of the second power light and used for measuring the power of the second power light; and the acquisition module is used for acquiring a spectral signal of the test light generated by the sample to be tested under the excitation of the first power light. According to the embodiment of the invention, non-contact and nondestructive measurement of the doping concentration distribution of the semiconductor structure can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of optical measurement, and in particular to a semiconductor structure doping concentration distribution measurement system. Background Art

[0002] The semiconductor structure has a diffusion layer, which is an important component and the key to forming a pn junction and separating free electrons and holes. The characteristics of the diffusion layer are usually characterized by the doping concentration distribution of the semiconductor structure.

[0003] In the related art, methods for measuring the doping concentration distribution of semiconductor structures generally include electrochemical capacitance-voltage profiler (ECV), secondary ion mass spectrometry (SIMS), spreading resistance profile (SRP), etc. The above measurement methods are contact-based and destructive and have limitations. Summary of the invention

[0004] In view of this, the present invention provides a semiconductor structure doping concentration distribution measurement system to solve the problem that the semiconductor structure doping concentration distribution measurement is contact- and destructive-related.

[0005] The present invention provides a semiconductor structure doping concentration distribution measurement system, comprising: an excitation module, used to generate excitation light; a spectroscopic module, located on the optical path of the excitation light, used to split the excitation light into a first power light and a second power light, wherein the first power light is used to irradiate a sample to be tested; a measuring module, located on the optical path of the second power light, used to measure the power of the second power light; and an acquisition module, used to acquire a spectral signal of a test light generated by the sample to be tested under the excitation of the first power light.

[0006] Beneficial effects: After the measurement system is calibrated using a calibration sample with a known doping concentration distribution, the doping concentration distribution of the sample to be measured can be measured. At this time, different samples to be measured can be measured without changing the measurement system. The measurement system has high applicability, is convenient and fast, and has a short measurement time and high measurement accuracy. The measurement system uses a non-contact, non-destructive measurement method, which reduces the probability of damage to the sample to be measured.

[0007] In an optional implementation, the semiconductor structure doping concentration distribution measurement system further includes: a dichroic mirror, wherein the dichroic mirror is located on the optical path of the test light, and the test light is refracted by the dichroic mirror to the acquisition module.

[0008] Beneficial effect: It can filter out stray light in the test light, avoid the measurement result being disturbed by the stray light, and improve the accuracy of the measurement structure.

[0009] In an optional embodiment, the semiconductor structure doping concentration distribution measurement system also includes: a neutral density filter, which is located on the optical path of the test light and between the dichroic mirror and the acquisition module; and a first focusing lens, which is located on the optical path of the test light and between the dichroic mirror and the neutral density filter.

[0010] Beneficial effects: It can attenuate the light intensity of the test light without changing the spectral energy distribution of the test light, so as to prevent damage to the acquisition module or inaccurate acquisition data caused by excessive light, and the first focusing lens can focus the test light to reduce the light spot of the test light incident on the acquisition module, thereby improving the reliability of data acquisition.

[0011] In an optional embodiment, the semiconductor structure doping concentration distribution structure measurement system also includes: a first objective lens, the first objective lens is located on the optical path of the first power light and the optical path of the excitation light, the dichroic mirror is located between the first objective lens and the first objective lens, the first power light irradiates the sample to be measured after passing through the first objective lens, and the excitation light passes through the first objective lens and is emitted to the dichroic mirror.

[0012] Beneficial effect: The first power light can be focused to reduce the spot size incident on the sample to be tested, so as to improve the accuracy of the excited area of ​​the sample to be tested.

[0013] In an optional embodiment, the semiconductor structure doping concentration distribution measurement system also includes: a carrying module, the carrying module having a through hole and a carrying surface, the carrying surface being movable relative to the through hole, the carrying surface being used to carry the sample to be measured, and the first power light passing through the through hole; a position control module, the position control module being connected to the carrying module, and the position control module controlling the displacement of the carrying surface relative to the through hole.

[0014] Beneficial effects: The micro-movement of the sample to be tested is achieved, the measurement position of the sample to be tested is more precise, and the measurement accuracy is high.

[0015] In an optional embodiment, the semiconductor structure doping concentration distribution measurement system also includes: an imaging light source, used to generate imaging light, wherein the imaging light is used to illuminate the area of ​​the sample to be tested that is excited by the first power light; a reflective module, wherein the imaging light is reflected by the sample to be tested to the reflective module; and an imaging module, wherein the imaging light is reflected by the reflective module to the imaging module.

[0016] Beneficial effect: The current detection area of ​​the sample to be tested can be obtained in time, so that the position of the sample to be tested can be adjusted according to the test needs, and the current detection area is ensured to meet the test needs, thereby improving the detection accuracy.

[0017] In an optional implementation, it further includes: a second objective lens, wherein the second objective lens is located on the optical path of the imaging light and between the reflective module and the imaging module.

[0018] Beneficial effect: The imaging light is focused and the spot size incident on the imaging module is reduced to improve the spatial resolution.

[0019] In an optional embodiment, the semiconductor structure doping concentration distribution measurement system further includes: a processing module, the acquisition module, the position control module and the imaging module are all connected to the processing module, and the processing module is used to process the spectral signal of the test light.

[0020] Beneficial effect: The linkage efficiency among the acquisition module, the position control module and the imaging module is higher, which is conducive to improving the test accuracy.

[0021] In an optional embodiment, the semiconductor structure doping concentration distribution measurement system also includes: a second focusing lens, which is located on the optical path of the second power light and between the spectroscopic module and the measurement module; and / or a collimator, which is located on the optical path of the excitation light and between the excitation module and the spectroscopic module.

[0022] Beneficial effects: the collimation of the excitation light is ensured, and the second power light is focused on the measurement module, thereby improving the accuracy of the measurement.

[0023] In an optional implementation, the power of the first-power light is greater than the power of the second-power light.

[0024] Beneficial effects: improving the excitation effect on the sample to be tested and reducing the cost of the measurement module. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1is a schematic structural diagram of a measurement system according to an embodiment of the present invention;

[0027] Figure 2 It is the spectrum of the sample to be tested in the excited state.

[0028] Description of reference numerals:

[0029] 1. Measurement system; 2. Sample to be measured;

[0030] 100, excitation module; 101, optical fiber; 110, beam expander group; 120, collimator;

[0031] 200, a light splitting module; 210, a first objective lens;

[0032] 300, measuring module; 310, second focusing lens;

[0033] 400, acquisition module; 410, dichroic mirror; 420, neutral density filter; 430, first focusing lens; 440, acquisition card;

[0034] 500, bearing module; 510, through hole; 520, bearing surface;

[0035] 600, position control module;

[0036] 700, imaging light source; 710, reflective module; 720, imaging module; 730, second objective lens;

[0037] 800. Processing module. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0040] In the description of the present invention, "plurality" means two or more. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Photoluminescence (PL) spectroscopy is a non-contact and non-destructive characterization tool that can be used to evaluate the basic properties of semiconductor structures. The PL spectrum is related to factors such as the sample's temperature, doping concentration distribution, interband absorption, and radiative recombination. Changes in any of these parameters will affect the intensity and shape of the PL spectrum. Therefore, in theory, changes in the PL spectrum can be used to qualitatively characterize the doping concentration distribution of the diffusion layer.

[0043] Photoluminescence technology uses laser to illuminate the surface of semiconductor structure, so that the carriers in silicon material are in a higher energy excited state. Then, in a very short time, the carriers return from the excited state to the ground state, at which time, the energy is released in the form of photons. Depending on the characteristics of the diffusion layer, the frequency and intensity of the photons emitted by the silicon material are also different. Therefore, the doping concentration distribution of the diffusion layer can be further studied by analyzing its PL spectrum.

[0044] Laser irradiates the surface of semiconductor structure, exciting the silicon substrate and diffusion layer to produce different photons. Figure 2 As shown in the curve in the middle (a) area, the PL spectrum includes three obvious components, the band-to-band emission (Si BB) spectrum peak of the silicon substrate corresponding to λ1, the band-to-band emission (HDBB) spectrum peak of the heavily doped diffusion layer corresponding to λ2, and the zone-center optical photon replica (PR of HDBB) spectrum peak of HDBB corresponding to λ3. Due to the narrowing effect of the band gap of the diffusion layer, the energy of the HDBB spectrum peak is lower (i.e., the wavelength is longer). And due to the band filling and band tailing effects in heavily doped silicon, the HDBB spectrum peak is significantly wider than the Si BB spectrum peak.

[0045] At room temperature, Figure 2As shown in the curve in the middle (b) area, due to the thermal broadening effect, the HDBB spectrum peak and the Si BB spectrum peak are difficult to distinguish and merge into a very wide spectrum peak. Due to the existence of the HDBB spectrum peak, in the long-wave band, the spectrum emitted by the diffusion layer is still significantly different from the spectrum emitted by the silicon substrate (where Figure 2 The black solid line in region (b) is the spectrum curve with the diffusion layer, and the red dotted line is the spectrum curve without the diffusion layer). Therefore, even at room temperature, this spectral characteristic can be used to study the doping concentration distribution of the diffusion layer.

[0046] After standard high-temperature diffusion, the doping concentration distribution of the semiconductor structure satisfies the Gaussian distribution, as shown in the following formula:

[0047]

[0048] Among them, N p is the peak concentration, z p is the depth of peak concentration, z f is the depth factor. f and z p There is an inherent correlation in the standard high-temperature diffusion process, that is, the deeper the peak concentration is located, the deeper the dopant atoms diffuse into the silicon substrate. If photoluminescence spectroscopy is used to characterize the diffusion layer, the PL spectrum needs to be converted into a parameter set {N p ,z p ,z f} to reconstruct the doping concentration distribution.

[0049] According to the above principles, a numerical model of PL spectrum and doping concentration distribution is established:

[0050] I1 is defined as the integrated intensity between the wavelength λ1 of the Si BB spectrum peak and the wavelength λ2 of the HDBB spectrum peak (dominated by the silicon substrate), I2 is defined as the integrated intensity between the wavelength λ2 of the HDBB spectrum peak and the wavelength λ3 of the PR of HDBB spectrum peak (dominated by the diffusion layer), and the integrated intensity ratio R=I2 / I1 is used to quantitatively characterize the diffusion layer.

[0051] Under the laser condition of wavelength λexc1, the integrated intensity ratio R1 and N are obtained. p ×(z p +z f ), under the laser bar with wavelength λexc2, the integrated intensity ratio R2 is obtained, and the relative change of the integrated intensity ratio (R1-R2) / R1 and z f The function relationship of the two functions is used to solve the parameter N p 、z p 、z f Finally, the above formula is used to reconstruct the doping concentration distribution of the diffusion layer.

[0052] Combine the following Figure 1 to Figure 2 , describing an embodiment of the present invention.

[0053] According to an embodiment of the present invention, a semiconductor structure doping concentration distribution measurement system 1 is provided. The measurement system 1 includes an excitation module 100 , a spectroscopic module 200 , a measurement module 300 and a collection module 400 .

[0054] The excitation module 100 is used to generate excitation light, the spectrometer module 200 is located on the optical path of the excitation light, the spectrometer module 200 is used to divide the excitation light into a first power light and a second power light, the first power light is used to irradiate the sample 2 to be tested, the measurement module 300 is located on the optical path of the second power light, the measurement module 300 is used to measure the power of the second power light, and the acquisition module 400 is used to acquire the spectral signal of the test light generated by the sample 2 to be tested under the excitation of the first power light.

[0055] It should be noted that the sample 2 to be tested is a semiconductor structure, wherein the sample 2 to be tested can be a crystalline silicon solar cell. The excitation module 100 can include a wavelength-adjustable laser. When the laser is a fiber laser, the excitation module 100 also includes a single-mode optical fiber 101. The laser of the laser propagates along the single-mode optical fiber 101. The single-mode optical fiber 101 has a beam shaping function to improve the beam quality of the excitation light. The acquisition module 400 can be a detector, such as a spectrometer or a spectral detector, etc. The acquisition module 400 can be connected to an acquisition card 440 for collecting spectral signals. The spectroscopic module 200 can be a device with spectroscopic capabilities such as a beam splitter.

[0056] By setting up the excitation module 100, it is possible to generate excitation light for exciting the sample 2 to be tested. The sample 2 to be tested generates test light in the excitation state. The test light is emitted to the acquisition module 400. The acquisition module 400 collects the spectral signal of the test light, thereby determining the doping concentration distribution of the sample 2 to be tested.

[0057] Specifically, before testing the sample 2, a known doping concentration distribution (i.e., a known N p 、z p 、z f , and z p and z f The calibration sample is used to generate an integral intensity ratio R1 and N, and the excitation module 100 is used to emit excitation light, so that the calibration sample generates a spectral signal under the excitation state. p ×(z p +z f ), and (R1-R2) / R1 and z fThe second functional relationship can then be used to excite different regions of the same standard sample, or to excite multiple standard samples with different doping concentration distributions, to obtain multiple first functional relationships and multiple second functional relationships, and to fit a standard curve.

[0058] After obtaining the above standard curve, the sample 2 to be tested is excited by the excitation light of the above wavelength to obtain the integrated intensity ratio R1 and the integrated intensity ratio R2 generated by the sample 2 to be tested, and the N of the sample 2 to be tested is obtained by using the above standard curve. p 、z p 、z f , combined with the above Gaussian distribution formula, the doping concentration distribution of the sample 2 to be tested is obtained.

[0059] Since the spectroscopic capability of the spectroscopic module 200 is fixed, the ratio of the power of the first-power light to the power of the second-power light is fixed. By setting the measuring module 300, the power of the second-power light can be measured in real time, and then the power of the first-power light can be confirmed, thereby achieving the effect of monitoring the power of the first-power light incident on the sample to be tested 2, ensuring that the power of the laser incident on the surface of the sample to be tested 2 is the same each time, thereby improving the accuracy of the test.

[0060] In this way, after the measurement system 1 is calibrated using a calibration sample with a known doping concentration distribution, the doping concentration distribution of the sample 2 to be measured can be measured. At this time, different samples 2 to be measured can be measured without changing the measurement system 1. The measurement system 1 has high applicability, is convenient and fast, has a short measurement time, and has high measurement accuracy. In addition, the measurement method of the measurement system 1 is non-contact and non-destructive measurement, which reduces the probability of damage to the sample 2 to be measured.

[0061] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 also includes a dichroic mirror 410, which is located on the optical path of the test light, and the test light is refracted by the dichroic mirror 410 to the acquisition module 400. By setting the dichroic mirror 410, stray light in the test light can be filtered out, the measurement result can be prevented from being disturbed by the stray light, and the accuracy of the measurement structure can be improved.

[0062] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 also includes a neutral density filter 420 and a first focusing lens 430. The neutral density filter 420 is located on the optical path of the test light, and the neutral density filter 420 is located between the dichroic mirror 410 and the acquisition module 400. The first focusing lens 430 is located on the optical path of the test light, and the first focusing lens 430 is located between the dichroic mirror 410 and the neutral density filter 420.

[0063] By setting the neutral density filter 420, the intensity of the test light can be attenuated without changing the spectral energy distribution of the test light, thereby preventing damage to the acquisition module 400 or inaccurate acquisition data caused by excessive light, which is beneficial to ensuring the reliability and service life of the data collected by the acquisition module 400.

[0064] In addition, by providing the first focusing lens 430, the test light can be focused to reduce the light spot of the test light incident on the acquisition module 400, avoid the test light being outside the acquisition area of ​​the acquisition module 400, and improve the reliability of data acquisition.

[0065] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution structure measurement system 1 also includes a first objective lens 210. The first objective lens 210 is located on the optical path of the first power light and the optical path of the excitation light. The first power light irradiates the sample 2 to be measured after passing through the first objective lens 210, and the excitation light is emitted to the dichroic mirror 410 after passing through the first objective lens 210. The dichroic mirror 410 is located between the light splitting module 200 and the first objective lens 210.

[0066] By setting the first objective lens 210, the first power light can be focused and the spot size incident on the sample to be measured 2 can be reduced to improve the accuracy of the excited area of ​​the sample to be measured 2. That is to say, by increasing at least one of the magnification and the numerical aperture of the first objective lens 210, the spot size incident on the sample to be measured 2 can be reduced, thereby improving the accuracy of the excited area of ​​the sample to be measured 2, and the reliability of the measurement result of the measurement system 1 can be improved.

[0067] In addition, the test light generated by the sample 2 under excitation can be diffused through the first objective lens 210 , so that the spot of the test light irradiating the dichroic mirror 410 is larger, which is beneficial to improving the effect of the dichroic mirror 410 in filtering out stray light.

[0068] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 also includes a carrying module 500 and a position control module 600, the carrying module 500 has a through hole 510 and a carrying surface 520, the carrying surface 520 is movable relative to the through hole 510, the carrying surface 520 is used to carry the sample to be measured 2, the first power light passes through the through hole 510, the position control module 600 is connected to the carrying module 500, and the position control module 600 controls the displacement of the carrying surface 520 relative to the through hole 510.

[0069] For example, the supporting module 500 can be a piezoelectric control platform, and the position control module 600 can be a piezoelectric processing module. The piezoelectric control platform can achieve micron-level displacement to improve the displacement accuracy of the sample 2 to be tested, thereby improving the accuracy of the area of ​​the sample 2 to be tested that is excited by the first power light, and the measurement accuracy of the measurement system 1.

[0070] By providing the carrying module 500 and the position control module 600, the sample 2 to be tested can be slightly moved, the measurement position of the sample 2 to be tested is more accurate, the measurement accuracy is high, and the first power light is directed to different areas of the sample 2 to be tested, the spectral energy diagrams of different areas of the sample 2 to be tested are obtained, and the measurement data of the sample 2 to be tested is expanded, which is conducive to obtaining more accurate measurement results. In addition, since the through hole 510 is provided, even if the sample 2 to be tested moves, it will not affect the irradiation of the sample 2 to be tested by the first power light, ensuring the normal operation of the measurement system 1.

[0071] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 also includes an imaging light source 700, a reflective module 710 and an imaging module 720. The imaging light source 700 is used to generate imaging light, and the imaging light is used to illuminate the area of ​​the sample 2 to be tested that is excited by the first power light. The imaging light is reflected by the sample 2 to the reflective module 710, and the imaging light is reflected by the reflective module 710 to the imaging module 720.

[0072] For example, the imaging light source 700 may be an LED light source, the reflective module 710 may be a semi-transparent plane mirror, and the imaging module 720 may be a camera, such as a (Charge coupled Device, CCD) camera or a CMOS (Complementary Metal Oxide Semiconductor) camera. Of course, it is understandable that the imaging light source 700 may also be other types of light sources, the reflective module 710 may also be other devices with reflective functions, and the imaging module 720 may also be other image sensors.

[0073] By setting the imaging light source 700, the reflective module 710 and the imaging module 720, the current detection area of ​​the sample 2 to be tested can be obtained in time, so that the position of the sample 2 to be tested can be adjusted according to the test needs, and the current detection area can be ensured to meet the test needs, thereby improving the detection accuracy.

[0074] In addition, the reflective module 710 can be located between the imaging light source 700 and the sample to be tested 2. The imaging light of the imaging light source 700 and the sample to be tested 2 are perpendicular to each other. The angle between the reflective module 710 and the imaging light can be 45°. The image acquired by the imaging module 720 has better accuracy and less deformation, which is conducive to improving the test accuracy.

[0075] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 also includes a second objective lens 730, and the second objective lens 730 is located on the optical path of the imaging light, and the second objective lens 730 is located between the reflective module 710 and the imaging module 720. The imaging light is collected by the imaging module 720 after passing through the second objective lens 730.

[0076] By setting the second objective lens 730, the imaging light can be focused and the spot size incident on the imaging module 720 can be reduced to improve the spatial resolution. That is to say, at least one of the magnification and the numerical aperture of the second objective lens 730 is increased to reduce the spot size incident on the imaging module 720, thereby improving the spatial resolution.

[0077] By configuring the first objective lens 210 , the carrier module 500 and the second objective lens 730 , the detection area size of the sample 2 to be measured can reach the micron level, which can be used to detect the diffusion area of ​​micron size and improve the measurement accuracy of the measurement system 1 .

[0078] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 also includes a processing module 800, and the acquisition module 400, the position control module 600 and the imaging module 720 are all connected to the processing module 800, and the processing module 800 is used to process the spectral signal of the test light fed back by the acquisition module 400.

[0079] The processing module 800 may have a display screen or a touch screen, so that the user can observe the position of the sample 2 to be tested, the state of the carrier module 500 and the data of the acquisition module 400 in real time through the processing module, thereby improving the timeliness of feedback.

[0080] By setting up the processing module 800, it is possible to timely control the position of the sample 2 to be tested by controlling the position control module 600 through the position control module 600 according to the image state of the imaging module 720, so that the position of the sample 2 to be tested meets the test requirements, and it is possible to obtain the spectrum under the excitation state corresponding to different areas of the sample 2 to be tested according to the data of the acquisition module 400 and the image state of the imaging module 720. It is also possible to control the position of the sample 2 to be tested by controlling the position control module 600 through the position control module 600 according to the data of the acquisition module 400, so as to improve the test efficiency. The linkage efficiency among the acquisition module 400, the position control module 600 and the imaging module 720 is higher, which is conducive to improving the test accuracy.

[0081] like Figure 1As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 also includes a collimator 120, which is located on the optical path of the excitation light, and the excitation light passes through the collimator 120 and is emitted to the spectroscopic module 200. The collimator 120 is located between the excitation module 100 and the spectroscopic module 200. By setting the collimator 120, the collimation of the excitation light is ensured, and the accuracy and performance of the measurement system 1 are improved.

[0082] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 further includes a beam expander group 110, which is located on the optical path of the excitation light, and the excitation light passes through the beam expander group 110 and is emitted to the spectroscopic module 200. The beam expander group 110 is located between the excitation module 100 and the spectroscopic module 200, and specifically, the beam expander group 110 is located between the collimator 120 and the spectroscopic module 200.

[0083] For example, the beam expander assembly 110 may include a first lens 111 and a second lens 112. The first lens 111 is closer to the excitation module than the second lens 112. In other words, the excitation light first passes through the first lens 111, and then passes through the second lens 112 and then is emitted to the spectroscopic module. The first lens 111 can focus the excitation light, and the second lens 112 can diverge the excitation light.

[0084] In this way, the beam expander group 110 can change the beam diameter and divergence angle of the excitation light, calibrate the excitation light passing through the collimator 120, and increase the beam diameter of the excitation light so that the excitation light is distributed over a larger area on the spectrometer module 200, and the spectrometer module 200 has a better spectroscopic effect on the excitation light.

[0085] like Figure 1 As shown, in the technical solution of this embodiment, the semiconductor structure doping concentration distribution measurement system 1 further includes a second focusing lens 310, which is located on the optical path of the second power light, and the second power light passes through the second focusing lens 310 and is emitted to the measurement module 300. The second focusing lens 310 is located between the spectroscopic module 200 and the measurement module 300.

[0086] By providing the second focusing lens 310 , the second power light can be focused, and the spot size incident on the measuring module 300 can be reduced, so that the second power light is focused on the measuring part of the measuring module 300 , thereby improving the accuracy of the measurement.

[0087] In the technical solution of this embodiment, the power of the first power light is greater than the power of the second power light. The ratio of the power of the first power light to the power of the second power light can be 6 to 9, for example, the ratio of the power of the first power light to the power of the second power light is 6, 7, 8 or 9.

[0088] In this way, the main part of the excitation light is used to excite the sample 2 to be tested, thereby improving the excitation effect on the sample 2 to be tested, so as to ensure that the sample 2 to be tested can produce a reliable spectrum under the excitation of the first power light, thereby ensuring the acquisition accuracy of the acquisition module 400. In addition, since the power of the second power light is relatively small, the power detection upper limit requirement for the measurement module 300 is relatively low, which can reduce the cost of the measurement module 300, thereby reducing the cost of the measurement system 1.

[0089] It should be noted that when at least one of the numerical aperture of the first objective lens 210 , the numerical aperture of the second objective lens 730 , the energy of the excitation light, and the power of the excitation light is increased, the sensitivity of the PL spectrum to the measurement system 1 will be higher.

[0090] The following describes a measurement method for measuring a sample 2 using a measurement system 1:

[0091] First, a calibration sample is placed in the carrier module 500. The doping concentration distribution of the calibration sample is known, that is, the parameter N of the calibration sample is p 、z p 、z f , and z p and z f The relationship is known;

[0092] Then, the excitation module 100 is controlled to generate excitation light with wavelengths λexc1 and λexc2 to obtain R1 and N respectively. p ×(z p +z f ) and the first calibration curve of (R1-R2) / R1 and z f A second calibration curve is obtained, and a corresponding functional relationship is fitted through the two calibration curves;

[0093] Next, remove the calibration sample, place the sample 2 to be tested on the carrier module 500, control the excitation module 100 to generate excitation light with wavelengths λexc1 and λexc2, obtain R1exp and R2exp of the sample 2 to be tested, and use the first calibration curve, the second calibration curve, and z p and z f The function relationship is obtained to obtain the parameter N of the sample 2 to be tested. p 、z p 、z f .

[0094] Finally, according to the parameter N of the sample 2 to be tested p 、z p 、z f , combined with Reconstruct the doping concentration distribution curve of the sample 2 to be tested.

[0095] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A semiconductor structure doping concentration distribution measurement system, characterized in that: include: An excitation module (100), used for generating excitation light; A light splitting module (200), the light splitting module (200) being located on the optical path of the excitation light and used for splitting the excitation light into a first power light and a second power light, the first power light being used for irradiating a sample to be tested (2); A measuring module (300), the measuring module (300) being located on the optical path of the second-power light and being used to measure the power of the second-power light; The acquisition module (400) is used to acquire the spectrum signal of the test light generated by the sample to be tested (2) under the excitation of the first power light.

2. The semiconductor structure doping concentration distribution measurement system according to claim 1, characterized in that: Also includes: A dichroic mirror (410), the dichroic mirror (410) is located on the optical path of the test light, and the test light is refracted by the dichroic mirror (410) to the collection module (400).

3. The semiconductor structure doping concentration distribution measurement system according to claim 2, characterized in that: Also includes: a neutral density filter (420), the neutral density filter (420) being located on the optical path of the test light and between the dichroic mirror (410) and the acquisition module (400); A first focusing lens (430) is located on the optical path of the test light and between the dichroic mirror (410) and the neutral density filter (420).

4. The semiconductor structure doping concentration distribution measurement system according to claim 3, characterized in that: Also includes: A first objective lens (210), wherein the first objective lens (210) is located on an optical path of the first-power light and an optical path of the excitation light, and the dichroic mirror (410) is located between the first objective lens (210) and the dichroic mirror (410). The first-power light irradiates the sample to be tested (2) after passing through the first objective lens (210), and the excitation light is emitted toward the dichroic mirror (410) after passing through the first objective lens (210).

5. The semiconductor structure doping concentration distribution measurement system according to claim 1, characterized in that: Also includes: A carrying module (500), the carrying module (500) having a through hole (510) and a carrying surface (520), the carrying surface (520) being movable relative to the through hole (510), the carrying surface (520) being used to carry the sample to be tested (2), and the first power light passing through the through hole (510); A position control module (600), the position control module (600) is connected to the bearing module (500), and the position control module (600) controls the displacement of the bearing surface (520) relative to the through hole (510).

6. The semiconductor structure doping concentration distribution measurement system according to claim 5, characterized in that: Also includes: An imaging light source (700) for generating imaging light, wherein the imaging light is used to illuminate the area of ​​the sample to be tested (2) excited by the light of the first power; A reflective module (710), wherein the imaging light is reflected by the sample to be tested (2) to the reflective module (710); An imaging module (720), wherein the imaging light is reflected by the reflective module (710) to the imaging module (720).

7. The semiconductor structure doping concentration distribution measurement system according to claim 6, characterized in that: Also includes: A second objective lens (730), wherein the second objective lens (730) is located on the optical path of the imaging light and between the reflective module (710) and the imaging module (720).

8. The semiconductor structure doping concentration distribution measurement system according to claim 6, characterized in that: Also includes: The processing module (800) is connected to the acquisition module (400), the position control module (600) and the imaging module (720). The processing module (800) is used to process the spectral signal of the test light.

9. The semiconductor structure doping concentration distribution measurement system according to any one of claims 1 to 8, characterized in that: Also includes: a second focusing lens (310), the second focusing lens (310) being located on the optical path of the second power light and between the light splitting module (200) and the measuring module (300); and / or A beam expander lens group (110), the beam expander lens group (110) being located on the optical path of the excitation light and between the excitation module (100) and the light splitting module (200); and / or A collimator (120), the collimator (120) is located on the optical path of the excitation light and between the excitation module (100) and the light splitting module (200).

10. The semiconductor structure doping concentration distribution measurement system according to any one of claims 1 to 8, characterized in that: The power of the first-power light is greater than the power of the second-power light.

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