A method and a measuring platform for second harmonic characterization of semiconductor materials

Abstract

The application discloses a method and a measuring platform for characterizing semiconductor materials by using second harmonic waves, and the method comprises the following steps: splitting an initial light beam into a measurement light beam and a working light beam; irradiating the semiconductor material by using the working light beam to obtain a second harmonic signal for characterizing the semiconductor material; and correcting the second harmonic signal by using fluctuation data obtained by monitoring the measurement light beam, so as to take the corrected second harmonic signal as a characterization signal of the semiconductor material. The method and the measuring platform are used to solve the technical problem that the power fluctuation of an existing laser output light beam affects the stability of an SHG signal, and further affects the accuracy of defect parameter extraction of subsequent semiconductor materials. The technical effect of improving the stability of the SHG signal is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, and in particular to a method for characterizing semiconductor materials by second harmonic and a measuring platform. BACKGROUND

[0002] A large number of progress has been made in the field of semiconductor material characterization by using the nonlinear effect of the interaction between high-energy laser and materials by second harmonic (SHG).

[0003] However, when using SHG to characterize defects of semiconductor materials, the power of the laser output beam will fluctuate due to factors such as fluctuation of the injection current of the laser, change of the working temperature of the laser, change of the shape of the laser resonant cavity caused by external vibration, which will affect the stability of the SHG signal and the accuracy of the subsequent extraction of the defect parameters of the semiconductor materials. SUMMARY

[0004] In view of the above problems, the present application is proposed in order to provide a method for characterizing semiconductor materials by second harmonic and a measuring platform which overcome the above problems or at least partially solve the above problems.

[0005] In a first aspect, a method for characterizing semiconductor materials by second harmonic is provided, comprising:

[0006] splitting an initial light beam into a metrology light beam and a working light beam;

[0007] using the working light beam to irradiate the semiconductor material to obtain a second harmonic signal for characterizing the semiconductor material;

[0008] using fluctuation data obtained by monitoring the metrology light beam to correct the second harmonic signal, and using the corrected second harmonic signal as a characterization signal of the semiconductor material.

[0009] Optionally, the power ratio of the metrology light beam to the working light beam is 1:9.

[0010] Optionally, the fluctuation data is power fluctuation data.

[0011] Optionally, the initial light beam is a laser fundamental light beam.

[0012] Optionally, the using the fluctuation data obtained by monitoring the metrology light beam to correct the second harmonic signal comprises: aligning the fluctuation data with the second harmonic signal in time, and using the fluctuation data at the time points aligned with each other to correct the corresponding second harmonic signal.

[0013] In a second aspect, a second harmonic characterization measuring platform is provided, comprising: a laser, a beam splitter, a monitoring unit, a detector, and a sample stage.

[0014] The laser is used for emitting an initial light beam;

[0015] The beam splitter is used for splitting the initial light beam into a measurement light beam and a working light beam;

[0016] The detector is used for collecting a second harmonic signal reflected after the working light beam irradiates the semiconductor material placed on the sample table;

[0017] The monitoring unit is used for monitoring the measurement light beam to obtain fluctuation data, and the fluctuation data is used for correcting the second harmonic signal to obtain a characterization signal of the semiconductor material.

[0018] Optionally, the second harmonic characterization measurement platform further comprises a polarizer and a first objective lens between the beam splitter and the sample table; the polarizer is used for polarizing the working light beam; and the first objective lens is used for collimating the working light beam.

[0019] Optionally, the second harmonic characterization measurement platform further comprises a second objective lens, an analyzer and a filter between the sample table and the detector; the second objective lens is used for collimating a reflected light beam of the working light beam; the analyzer is used for analyzing the reflected light beam; and the filter is used for filtering out a fundamental wave light beam in the reflected light beam to obtain the second harmonic signal.

[0020] Optionally, the beam splitter is further used for splitting the initial light beam into the measurement light beam and the working light beam with a power ratio of 1:9.

[0021] Optionally, the detector is further used for receiving fluctuation data output by the monitoring unit, correcting the second harmonic signal according to the fluctuation data, and outputting the corrected second harmonic signal as the characterization signal of the semiconductor material.

[0022] The technical scheme provided in the embodiment of the application has at least the following technical effects or advantages:

[0023] The method and the measurement platform for characterizing the semiconductor material by the second harmonic provided in the embodiment of the application split the initial light beam into the measurement light beam and the working light beam, and obtain fluctuation data by monitoring the measurement light beam. Since the working light beam and the measurement light beam are both derived from the initial light beam, the fluctuation data of the measurement light beam can also represent the fluctuation state of the working light beam. The second harmonic signal obtained by the working light beam irradiating the semiconductor material is corrected by the fluctuation data, so that the instability interference caused by the fluctuation of the initial light beam on the second harmonic signal is removed, and the stability of the second harmonic signal and the accuracy of the characteristic parameters extracted subsequently are improved.

[0024] The above description is only a summary of the technical solutions of the present application. In order to enable a more thorough understanding of the technical means of the present application, the present application can be implemented according to the content of the specification, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more apparent and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Moreover, the same reference numerals in the drawings indicate the same or similar elements. In the drawings:

[0026] Figure 1 A structural diagram of a second harmonic characterization measurement platform in an embodiment of the present application;

[0027] Figure 2 A flowchart of a method for characterizing a semiconductor material by a second harmonic in an embodiment of the present application. DETAILED DESCRIPTION

[0028] Exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art.

[0029] Before introducing the method for characterizing a semiconductor material by a second harmonic provided by the present application, a second harmonic characterization measurement platform provided by the present application to which the method is applied will be introduced. As shown in Figure 1 The second harmonic characterization measurement platform includes a laser 1, a beam splitter 12, a monitoring unit 15, a detector 9 and a sample stage 11. The laser 1 is used to emit an initial light beam; the beam splitter 12 is used to split the initial light beam into a measurement light beam and a working light beam; the detector 9 is used to collect a second harmonic signal reflected after the working light beam irradiates a semiconductor material placed on the sample stage 11; and the monitoring unit 15 is used to monitor the measurement light beam to obtain fluctuation data, which is used to correct the second harmonic signal to obtain a characterization signal of the semiconductor material.

[0030] The present embodiment provides a method for characterizing a semiconductor material by a second harmonic, which is applied to Figure 1 As shown in the system, Figure 2 The method includes:

[0031] Step S201, splitting the initial light beam into a measurement light beam and a working light beam;

[0032] Step S202, irradiating the semiconductor material with the working light beam to obtain a second harmonic signal characterizing the semiconductor material;

[0033] Step S203, correcting the second harmonic signal by using fluctuation data obtained by monitoring the metrology light beam, and taking the corrected second harmonic signal as the signal characterizing the semiconductor material.

[0034] It should be noted that the type of the characteristic of the semiconductor material characterized by the second harmonic in the embodiment can be various, for example, by the relationship between the SHG intensity and the sample azimuth angle under different polarization configuration conditions, information of Si interface and bulk material can be obtained; reflected SHG can also characterize information of GaN surface layer crystal quality; SHG can also quickly characterize SiC hexagonal and cubic layer defect; SHG scanning can characterize SOI multi-layer dielectric film system copper ion contamination. This is not limited, and will not be listed one by one.

[0035] The method for characterizing the semiconductor material by the second harmonic provided in the embodiment will be described in detail below in combination with Figure 1 and Figure 2

[0036] Firstly, the laser 1 emits an initial light beam, which is a laser fundamental light beam.

[0037] Then, step S201 is performed, and the initial light beam is split into a metrology light beam 13 and a working light beam 14 by the beam splitter 12.

[0038] It should be noted that since the working light beam 14 and the metrology light beam 13 are both derived from the initial light beam emitted by the laser 1, the fluctuation states of the two light beams are synchronized.

[0039] Preferably, the power ratio of the metrology light beam split by the beam splitter 12 and the working light beam is 1:9, so as to ensure the laser intensity incident on the semiconductor material on the basis of ensuring the monitoring accuracy of the fluctuation data, and further ensure the test accuracy.

[0040] ​The metering beam 13 after beam splitting is collected by the monitoring unit 15. The monitoring unit 15 monitors the metering beam 13 to obtain fluctuation data. This fluctuation data can be power fluctuation data (e.g., power is P at time t0, power is 0.99P at time t1, power is 1.01P at time t2, etc.). The corresponding monitoring unit 15 is a power meter. The monitoring unit 15 monitors the real-time power fluctuation data by receiving the metering beam 13. Since the fluctuation of the laser 1 is often due to power fluctuation, the power fluctuation ratio of the working beam 14 and the metering beam 13 is the same. That is, the power fluctuation ratio of the beam that finally hits the sample and meets the test requirements is the same as the power fluctuation ratio of the metering beam 13 monitored by the monitoring unit 15. Therefore, setting the fluctuation data to power fluctuation data can better achieve the correction of the subsequent second harmonic signal and improve the characterization accuracy. Of course, the fluctuation data can also be wavelength fluctuation data. The corresponding monitoring unit 15 is a wavelength detector. No limitation is made here.

[0041] After beam splitting, the working beam 14 enters step S202, where the working beam 14 is used to irradiate the semiconductor material to obtain the second harmonic signal characterizing the semiconductor material.

[0042] like Figure 1 As shown, the semiconductor material 10 is placed on the sample stage 11. In the incident light path: a polarizer 2 and a first objective lens 3 can also be disposed between the beam splitter 12 and the sample stage 11. The polarizer 2 is used to polarize the working beam 14 to give it a specific polarization state, and the first objective lens 3 is used to focus and collimate the working beam 14. The working beam after polarization and collimation better meets the requirements of characterization testing.

[0043] The working beam interacts with defects in the semiconductor material 10 to generate a second harmonic signal, and a reflected beam is reflected from the semiconductor material 10. The reflected beam contains the fundamental wave beam and the second harmonic signal from the working beam 14.

[0044] In the reflected light path, a second objective lens 5, an analyzer 6, and a filter 7 can be arranged between the sample stage 11 and the detector 9. The second objective lens 5 is used to collimate the reflected beam of the working beam; the analyzer 6 is used to analyze the reflected beam to obtain a beam with a specific polarization state; and the filter 7 is used to filter out the fundamental wave beam in the reflected beam to obtain the second harmonic signal. This second harmonic signal, carrying sample defect information, is collected by the detector 9.

[0045] In the specific implementation process, the defects at different positions of the semiconductor material 10 can also be detected by moving the sample table 11 or the semiconductor material 10 on the sample table 11. Moreover, the instrument on the incident light path can be arranged to cooperate with the instrument on the reflected light path to adjust the incident angle of the working light beam 14 to the semiconductor material 10, so that the second harmonic signal under different incident angles can be obtained, thereby obtaining more abundant quantitative analysis defect information.

[0046] Then, the step S203 is entered, and the fluctuation data obtained by monitoring the metering light beam is used to correct the second harmonic signal, and the corrected second harmonic signal is used as the characterization signal of the semiconductor material.

[0047] Specifically, after the monitoring unit 15 monitors the fluctuation data obtained by the metering light beam 13, the fluctuation data can be sent to the detector 9, and the detector 9 corrects the second harmonic signal according to the fluctuation data, thereby outputting the corrected second harmonic signal as the characterization signal of the semiconductor material 10 (for example, the detector 9 detects and records the SHG intensity carrying the defect information; the SHG signal is automatically corrected according to the fluctuation of the real-time power P in the fluctuation data; and finally, the SHG signal corrected without being affected by the fluctuation of the output power of the laser is output). The monitoring unit 15 can also send the fluctuation data to the computing device, and the detector 9 also sends the second harmonic signal to the computing device, and the computing device corrects the second harmonic signal according to the fluctuation data, thereby outputting the corrected second harmonic signal as the characterization signal of the semiconductor material 10 (for example, the computing device first acquires the real-time power P of the metering light beam 13 monitored by the monitoring unit 15 and judges the fluctuation of P, wherein the fluctuation proportion of the power of the metering light beam 13 is the same as that of the incident fundamental wave light beam meeting the test requirements of the sample, and then the computing device acquires the SHG signal carrying the defect information of the sample from the detector 9, automatically corrects the SHG signal according to the fluctuation of P, and finally outputs the SHG signal corrected without being affected by the fluctuation of the output power of the laser), which is not limited herein.

[0048] In the specific implementation process, the fluctuation data and the second harmonic signal can be aligned in time, and the fluctuation data at the aligned time points is used to correct the corresponding second harmonic signal. Alternatively, it is directly assumed that the fluctuation data and the second harmonic signal are synchronous, and synchronous correction is performed.

[0049] The specific correction method of the second harmonic can be various. Preferably, since the second harmonic signal is proportional to the square of the power of the fundamental wave signal, the second harmonic signal can be divided by the square of the fluctuation ratio of the fundamental wave power to offset the fluctuation of the power. For example, if the ideal output power of the laser is P, the second harmonic signal is proportional to P 2But the laser output power fluctuation is 1.01P due to the temperature change, current change and resonant cavity shape change mentioned above, so the second harmonic signal is proportional to 1.01 2 P 2 Therefore, the second harmonic signal is corrected to 1.01 2 P 2 / 1.01 2 , that is, the second harmonic signal is divided by the square of the fluctuation ratio of the fundamental wave power.

[0050] Specifically, the application adopts a measurement platform combining monitoring laser power fluctuation and automatic correction of data, realizes real-time monitoring of the output power of the laser, and corrects the SHG signal carrying sample defect information according to the fluctuation of the output power, eliminates the influence of the output power fluctuation of the laser on the SHG signal, and improves the stability of the SHG signal.

[0051] Based on the same inventive concept, the embodiments of the application also provide a second harmonic characterization measurement platform, as shown in Figure 1 , comprising a laser 1, a beam splitter 12, a monitoring unit 15, a detector 9 and a sample stage 11.

[0052] The laser 1 is used to emit an initial light beam.

[0053] The beam splitter 12 is used to split the initial light beam into a measurement light beam 13 and a working light beam 14.

[0054] The detector 9 is used to collect the second harmonic signal 8 reflected after the working light beam 14 irradiates the semiconductor material 10 placed on the sample stage 11.

[0055] The monitoring unit 15 is used to monitor the measurement light beam 13 to obtain fluctuation data, and the fluctuation data is used to correct the second harmonic signal 8 to obtain a characterization signal of the semiconductor material 10.

[0056] In an optional embodiment, the second harmonic characterization measurement platform further comprises:

[0057] A polarizer 2 and a first objective lens 3 located between the beam splitter 12 and the sample stage 11.

[0058] The polarizer 2 is used to polarize the working light beam 14, and the first objective lens 3 is used to collimate the working light beam 14.

[0059] In an optional embodiment, the second harmonic characterization measurement platform further comprises:

[0060] A second objective lens 5, an analyzer 6 and a filter 7 located between the sample stage 11 and the detector 9.

[0061] The second objective 5 is used to collimate the reflected light beam of the working light beam 14; the polarizer 6 is used to detect the polarization of the reflected light beam, and the filter 7 is used to filter the fundamental light beam in the reflected light beam to obtain the second harmonic signal 8.

[0062] In an optional embodiment, the beam splitter 12 is also used to split the initial light beam into the metering light beam 13 and the working light beam 14 with a power ratio of 1:9.

[0063] In an optional embodiment, the probe 9 is also used to:

[0064] Receive the fluctuation data output by the monitoring unit 15, and correct the second harmonic signal 8 according to the fluctuation data, so as to output the corrected second harmonic signal as the characterization signal of the semiconductor material 10.

[0065] Since the measurement platform introduced in the embodiments of the present application is the measurement platform used for implementing the method of the embodiments of the present application, the specific structure and deformation of the measurement platform can be understood by those skilled in the art based on the method introduced in the embodiments of the present application, and therefore will not be described here. Any measurement platform used by the method of the embodiments of the present application belongs to the scope of the present application.

[0066] The technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0067] The method and measurement platform for characterizing semiconductor materials by using the second harmonic provided in the embodiments of the present application split the initial light beam into a metering light beam and a working light beam, obtain fluctuation data by monitoring the metering light beam, since the working light beam and the metering light beam are both derived from the initial light beam, the fluctuation data of the metering light beam can also characterize the fluctuation state of the working light beam, and the second harmonic signal obtained by irradiating the semiconductor material with the working light beam is corrected by using the fluctuation data, which can remove the unstable interference caused by the fluctuation of the initial light beam on the second harmonic signal, and improve the stability of the second harmonic signal and the accuracy of the characteristic parameters extracted therefrom.

[0068] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not described in detail in order not to obscure the understanding of the present specification.

[0069] Similarly, it is to be understood that the embodiments of the present application can be placed into practice notwithstanding modifications to form yet further embodiments of the present application. As such, the terms and expressions of the foregoing description are used solely by way of the example thereof, but to the extent possible no limitation is intended to the details of the construction described herein other than as described in the claims. In this manner, the embodiments of the present application as described herein are susceptible to modifications and alternative forms known to those skilled in the art. It is, therefore, desired to be protected in the broadest scope of the appended claims as they can be interpreted to cover the subject matter of the above description.

[0070] Those skilled in the art can appreciate that modules in the apparatus in the embodiments can be adaptively changed and disposed in one or more apparatuses different from the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and further can be divided into multiple sub-modules or sub-units or sub-components. Any combination of all the features disclosed in the specification (including the accompanying claims, abstract and drawings), and any method or apparatus of all the processes or units disclosed in the specification as such can be adopted in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless explicitly stated otherwise, each feature disclosed in the specification (including the accompanying claims, abstract and drawings) can be replaced by an alternative feature providing the same, equivalent or similar function.

[0071] Furthermore, those skilled in the art will appreciate that the features of the various embodiments can be combined with each other, as the combinations of features from different embodiments are within the scope of the present application and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0072] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps not listed in a claim. The word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a unitary claim, several devices or means can be listed, comprising means which can be implemented by one and the same hardware item. The use of the word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The word 'first','second', 'third' etc. can merely be used for distinguishing between similar elements, and do not imply any order or priority.

Claims

1. A method of characterizing a semiconductor material by second harmonic generation, the method comprising: The method comprises: splitting an initial light beam into a measurement light beam and a working light beam, the working light beam having the same power fluctuation proportion as the measurement light beam; irradiating the semiconductor material with the working light beam to obtain a second harmonic signal representing the semiconductor material; correcting the second harmonic signal by using fluctuation data obtained by monitoring the measurement light beam, and taking the corrected second harmonic signal as the representation signal of the semiconductor material; the fluctuation data comprises power fluctuation data used for representing the fluctuation of real-time power.

2. The method of claim 1, wherein, The power ratio of the measurement light beam and the working light beam is 1:

9.

3. The method of claim 1, wherein, The fluctuation data further comprises wavelength fluctuation data.

4. The method of claim 1, wherein, The initial light beam is a laser fundamental light beam.

5. The method of claim 1, wherein, The method of correcting the second harmonic signal by using the fluctuation data obtained by monitoring the measurement light beam comprises: aligning the fluctuation data and the second harmonic signal in time, and correcting the corresponding second harmonic signal with the fluctuation data at the aligned time points.

6. A second harmonic characterisation measurement platform, characterised in that, The apparatus comprises: a laser, a beam splitter, a monitoring unit, a detector and a sample stage; the laser is configured to emit an initial light beam; the beam splitter is configured to split the initial light beam into a measurement light beam and a working light beam, the working light beam having the same power fluctuation proportion as the measurement light beam; the detector is configured to collect a second harmonic signal reflected after the working light beam irradiates a semiconductor material placed on the sample stage; the monitoring unit is configured to monitor the measurement light beam to obtain fluctuation data, the fluctuation data being used for correcting the second harmonic signal, and the corrected second harmonic signal being used as the representation signal of the semiconductor material; the fluctuation data comprises power fluctuation data used for representing the fluctuation of real-time power.

7. The second harmonic characterization measurement platform of claim 6, wherein, The apparatus further comprises: a polarizer and a first objective lens located between the beam splitter and the sample stage; the polarizer is configured to polarize the working light beam; the first objective lens is configured to collimate the working light beam.

8. The second harmonic characterization measurement platform of claim 6, wherein, The apparatus further comprises: a second objective lens, an analyzer and a filter located between the sample stage and the detector; the second objective lens is configured to collimate a reflected light beam of the working light beam; the analyzer is configured to analyze the reflected light beam, and the filter is configured to filter out a fundamental light beam in the reflected light beam to obtain the second harmonic signal.

9. The second harmonic characterization measurement platform of claim 6, wherein, The beam splitter is further configured to split the initial light beam into the measurement light beam and the working light beam, the power ratio of the measurement light beam and the working light beam being 1:

9.

10. The second harmonic characterization measurement platform of claim 6, wherein, The detector is further configured to: receive the fluctuation data output by the monitoring unit, correct the second harmonic signal according to the fluctuation data, and output the corrected second harmonic signal as the representation signal of the semiconductor material.

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