Micro-area infrared probe

Abstract

The invention discloses a micro-area infrared probe. The micro-area infrared probe comprises a micro-area infrared light source, a reflecting mirror, a Cassegrain prism and a vacuum sample cavity, the micro-area infrared light source is used for emitting multiple beams of parallel infrared light; the reflecting mirror is arranged on a light path of the infrared light and is used for reflecting the infrared light; the Cassegrain prism is arranged on a light path of the reflected infrared light and is used for focusing the plurality of beams of parallel infrared light; the vacuum sample cavity is arranged on a light path of the focused infrared light and is used for accommodating a sample to be detected, and the infrared light can enter the vacuum sample cavity. According to the micro-area infrared probe, the Cassegrain prism is matched with the vacuum sample cavity, infrared light can be focused on the surface of a sample, the micron-level resolution ratio is achieved, the detection precision is improved, and oxidation of a two-dimensional material heterogeneous integrated device caused by factors such as moisture and oxygen is effectively avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of vacuum detection, and in particular relates to a micro-area infrared probe. Background Art

[0002] The two-dimensional material layers are combined by van der Waals forces, which are easy to dissociate and integrate, making them suitable for constructing new two-dimensional material heterogeneous integrated devices. Such devices have wide applications in new electronic and optoelectronic fields. Among them, the micro-area identification and interface contact characteristics of two-dimensional material heterogeneous integrated devices are the key basis for exploring the novel physical properties of heterojunctions. However, there are currently the following technical bottlenecks: the interface contact of two-dimensional materials will be affected by the fragility and uncertainty of their transfer and stacking process, resulting in poor interface contact. Some two-dimensional materials, such as black phosphorus, two-dimensional ferromagnetic and ferroelectric materials, are sensitive to oxygen and moisture and cannot maintain their intrinsic properties in atmospheric environment. The micro-area identification of two-dimensional material heterogeneous integrated devices is difficult and the accuracy is insufficient. The first two technical bottlenecks are mainly caused by the dissociation and stacking of two-dimensional material heterojunctions in atmospheric environment, so the use of ultra-high vacuum two-dimensional material high-precision dissociation and stacking equipment can be better solved. High-sensitivity micro-area identification and characterization of two-dimensional material heterogeneous integrated devices are still very challenging.

[0003] The existing technology usually uses the grazing incidence specular reflection absorption infrared method to perform infrared analysis on samples under ultra-high vacuum conditions, but there are still the following problems: the analysis area size is usually at the millimeter level, and can only provide statistical average infrared spectrum information, which is difficult to meet the needs of micro-area infrared analysis at the micrometer level, and the existing technology cannot focus on the sample surface. The existing technology's requirements for sample size are also limited to small-sized flag-shaped holders, and cannot adapt to large-sized 2-inch wafer samples.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a micro-area infrared probe, which can focus infrared light on the surface of a sample to be tested, thereby realizing micro-area identification of a heterojunction of a two-dimensional material.

[0006] In order to achieve the above-mentioned purpose, a technical solution provided by a specific embodiment of the present invention is as follows: a micro-area infrared probe, comprising: a micro-area infrared light source, a reflector, a Cassegrain prism and a vacuum sample chamber. The micro-area infrared light source is used to emit multiple parallel infrared light beams; the reflector is arranged on the optical path of the infrared light beams, and is used to reflect the infrared light beams; the Cassegrain prism is arranged on the optical path of the reflected infrared light beams, and is used to focus the multiple parallel infrared light beams; the vacuum sample chamber is arranged on the optical path of the focused infrared light beams, and is used to accommodate the sample to be tested, and the infrared light beams can enter the vacuum sample chamber.

[0007] In one or more embodiments of the present invention, the Cassegrain prism includes: a main prism, a first sub-prism and a second sub-prism. The infrared light reflected by the reflector can be incident from the main prism; the first sub-prism is arranged on one side of the main prism, and is used to reflect the infrared light focused and reflected by the main prism onto the sample to be tested in the vacuum sample chamber;

[0008] The second sub-prism is symmetrically arranged on the other side of the main prism relative to the first sub-prism, and is used to reflect the infrared light reflected by the sample to be tested onto the main prism; the infrared light is reflected by the main prism and emitted parallel to the incident direction.

[0009] In one or more embodiments of the present invention, the angle between the infrared light reflected by the first sub-prism and the normal line of the sample surface is 45°-60°.

[0010] In one or more embodiments of the present invention, the focal length of the Cassegrain prism is 10 mm-20 mm.

[0011] In one or more embodiments of the present invention, the micro-area infrared probe further includes an infrared detector disposed on the optical path of the emitted infrared light and configured to receive the infrared light reflected by the sample.

[0012] In one or more embodiments of the present invention, the micro-area infrared probe further comprises a visible light source coaxially arranged with the micro-area infrared light source; the optical path of the visible light emitted by the visible light source is the same as the optical path of the infrared light.

[0013] In one or more embodiments of the present invention, the micro-area infrared probe further includes a CCD camera, which is disposed on the optical path of the visible light and is used to observe the sample to be tested.

[0014] In one or more embodiments of the present invention, a spectrometer is provided between the CCD camera and the infrared detector for separating the infrared light from the visible light.

[0015] In one or more embodiments of the present invention, a knife-edge aperture is arranged between the Cassegrain prism and the beam splitter.

[0016] In one or more embodiments of the present invention, the vacuum sample chamber comprises: an ultra-high vacuum chamber, an infrared optical window and a four-axis sample holder. The infrared optical window is arranged on the ultra-high vacuum chamber to introduce the infrared light; the four-axis sample holder can translate the sample to be tested in three directions of X-axis, Y-axis and Z-axis and rotate the sample to be tested.

[0017] Compared with the prior art, the micro-area infrared probe of the present invention uses a Cassegrain prism in conjunction with a vacuum sample chamber, which can focus infrared light on the surface of the sample and achieve a resolution of micrometers, thereby improving the accuracy of detection and effectively avoiding the oxidation of two-dimensional material heterogeneous integrated devices by factors such as moisture and oxygen. The use of a four-axis sample holder realizes ultra-high vacuum micro-area infrared analysis of two-inch wafer samples, improves the control of the stacking accuracy of two-dimensional materials, broadens the applicability of the device, and thus ensures the accurate characterization of the intrinsic properties of the sample during the test. Furthermore, the use of a knife-edge aperture further improves the resolution of the micro-area infrared probe. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of a micro-area infrared probe in one embodiment of the present invention;

[0020] Figure 2 FIG. 4 is a schematic diagram of a Cassegrain prism according to an embodiment of the present invention.

[0021] Description of main reference numerals:

[0022] 1-micro-area infrared light source, 2-reflector, 3-Cassegrain prism, 31-primary prism, 32-first secondary prism, 33-second secondary prism, 4-vacuum sample chamber, 41-infrared optical window, 5-infrared detector, 6-visible light source, 7-CCD camera, 8-beam splitter, 9-knife-edge aperture. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions 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 only 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 ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0024] like Figure 1 As shown, a micro-area infrared probe in one embodiment of the present invention comprises: a micro-area infrared light source 1, a reflector 2, a Cassegrain prism 3 and a vacuum sample chamber 4. The micro-area infrared light source 1 is used to emit multiple parallel infrared light beams. The reflector 2 is arranged on the optical path of the infrared light beam, and is used to reflect the infrared light beam. The Cassegrain prism 3 is arranged on the optical path of the reflected infrared light beam, and is used to focus multiple parallel infrared light beams. The vacuum sample chamber 4 is arranged on the optical path of the focused infrared light beam, and is used to accommodate the sample to be tested, and the infrared light beam can enter the vacuum sample chamber 4.

[0025] In the above embodiment, the micro-area infrared probe of the present invention adopts a combination of a micro-area infrared light source 1 and a vacuum sample chamber 4, and utilizes the focusing characteristics of the Cassegrain prism 3 on infrared light, so as to focus the infrared light on the surface of the sample to be tested, thereby realizing high-precision, high-responsiveness, and wide-device-compatibility micro-area identification of two-dimensional material heterojunctions.

[0026] In one embodiment, the Cassegrain prism 3 includes: a main prism 31, a first sub-prism 32, and a second sub-prism 33. The infrared light reflected by the reflector 2 can be incident from the main prism 31. The first sub-prism 32 is arranged on one side of the main prism 31, and is used to reflect the infrared light focused and reflected by the main prism 31 onto the sample to be tested in the vacuum sample chamber. The second sub-prism 33 is symmetrically arranged on the other side of the main prism 31 relative to the first sub-prism 32, and is used to reflect the infrared light reflected by the sample to be tested onto the main prism 31. The infrared light is reflected by the main prism 31 and is emitted parallel to the incident direction.

[0027] The optical path of the infrared light at the Cassegrain prism 3 and the sample to be tested is as follows: the infrared light first reaches the main prism 31. The main prism 31 focuses the infrared light and reflects it onto the first sub-prism 32. The first sub-prism 32 then reflects the infrared light to the vacuum sample chamber 4, and then focuses it onto the surface of the sample to be tested. The sample to be tested then reflects the infrared light to the second sub-prism 33, and the second sub-prism 33 reflects the infrared light to the main prism 31. The main prism 31 focuses the infrared light and makes the infrared light emit parallel to its incident direction to the subsequent processing equipment. The infrared light is focused by the Cassegrain prism 3 so that the resolution of the infrared probe reaches the micrometer level, thereby realizing the micro-area infrared analysis of the sample to be tested.

[0028] Furthermore, the angle between the infrared light reflected by the first sub-prism 32 and the normal line of the sample surface is 45°-60°. It is understandable that since the second sub-prism 33 and the first sub-prism 32 are symmetrically arranged relative to the main prism 31, the angle between the infrared light reflected by the sample to the second sub-prism 33 and the normal line of the sample surface is also 45°-60°. The angle between the infrared light reflected by the first sub-prism 32 and the normal line of the sample surface is 45°-60°, which can improve the infrared light reflectivity of the sample and improve the accuracy of the probe.

[0029] In one embodiment, the focal length of the Cassegrain prism 3 is 10 mm-20 mm, so that the working distance between the sample to be tested and the Cassegrain prism 3 is 10 mm-20 mm. This distance enables the vacuum sample chamber 4 to be provided with an infrared optical window to improve the passing efficiency of infrared light.

[0030] In one embodiment, after the infrared light is reflected by the second sub-prism 33 and emitted from the Cassegrain prism 3, a corresponding processing device is required to analyze the infrared light reflected by the sample. The micro-area infrared probe also includes an infrared detector 5. The infrared detector 5 is arranged on the optical path of the infrared light emitted from the Cassegrain prism 3, and can receive the infrared light, and convert the received infrared light into a detectable electrical signal and record it so as to obtain relevant infrared data of the sample.

[0031] Since infrared light cannot be directly seen by human eyes, in order to facilitate the reflection of the focusing range of infrared light on the sample, the micro-area infrared probe is also provided with a visible light source 6. The visible light source 6 is coaxially arranged with the micro-area infrared light source 1. The optical path of the visible light emitted by the visible light source 6 is the same as the optical path of the infrared light, so that the optical field of the infrared light is replaced by the optical field of the visible light to adjust the position of the optical field or the sample.

[0032] In order to observe the sample, the micro-area infrared probe is also provided with a CCD camera 7. The CCD camera 7 is arranged on the optical path of the visible light and is used to observe the sample to be tested. Since the visible light path and the infrared light path of the CCD camera 7 are coaxially designed, when performing infrared analysis, the visible light field of view of the optical path of the CCD camera 7 will be affected and reduced to a small field of view; however, after the infrared test is completed, the visible light field of view can be restored to a normal large field of view, reaching the cm level, so as to perform macroscopic detection and observation of the entire sample.

[0033] In one embodiment, a spectrometer 8 is provided between the CCD camera 7 and the infrared detector 5 for separating infrared light from visible light, so that the infrared light is transmitted to the infrared detector 5 and the visible light is transmitted to the CCD camera 7 to reduce mutual interference between the two.

[0034] Furthermore, a knife-edge aperture 9 is provided between the Cassegrain prism 3 and the beam splitter 8. The knife-edge aperture 9 can assist the Cassegrain prism 3 to achieve a resolution of 20 μm level.

[0035] In one embodiment, the vacuum sample chamber 4 includes: an ultra-high vacuum chamber, an infrared optical window 41 and a four-axis sample holder. The ultra-high vacuum chamber, for example, can be a square or circular chamber, which effectively avoids the oxidation of the two-dimensional material heterogeneous integrated device by factors such as moisture and oxygen. The infrared optical window 41 is arranged on the ultra-high vacuum chamber for introducing infrared light. The four-axis sample holder can translate the sample in three directions of the X-axis, Y-axis and Z-axis and rotate the sample to be tested.

[0036] The four-axis sample holder can achieve a movement of ±25mm in the X direction, ±25mm in the Y direction, and ±50mm in the Z direction. It can rotate 360° and adjust its position relative to the infrared light field, so that the micro-area infrared probe can test two-inch wafer samples. And because of the use of a four-axis sample holder, the micro-area infrared probe can analyze the two-inch wafer sample one by one. The two-dimensional material heterojunctions in multiple tiny areas scattered on the two-inch wafer sample. Compared with the traditional statistical average infrared spectrum analysis, the micro-area infrared probe significantly improves the resolution of sample details and can more comprehensively reveal the intrinsic characteristics of two-dimensional material heterogeneous devices. In addition, the micro-area infrared probe also significantly improves the processing efficiency of multiple micro-areas on large-size wafers, providing a strong tool support for high-precision and high-sensitivity two-dimensional material device research.

[0037] In summary, the micro-area infrared probe of the present invention uses a Cassegrain prism 3 in conjunction with a vacuum sample chamber 4, which can focus infrared light on the surface of the sample and achieve a resolution of micrometers or even 20 μm, thereby improving the accuracy of detection and effectively avoiding the oxidation of two-dimensional material heterogeneous integrated devices by factors such as moisture and oxygen. The use of a four-axis sample holder realizes ultra-high vacuum micro-area infrared analysis of two-inch wafer samples, improves the control of the stacking accuracy of two-dimensional materials, broadens the applicability of the device, and thus ensures the accurate characterization of the intrinsic properties of the sample during the test. Furthermore, the use of a knife-edge aperture 9 further improves the resolution of the micro-area infrared probe.

[0038] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0039] 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 micro-area infrared probe, characterized in that: include: Micro-area infrared light source, used to emit multiple parallel infrared rays; A reflector, arranged on the optical path of the infrared light, for reflecting the infrared light; A Cassegrain prism, arranged on the optical path of the reflected infrared light, and used for focusing the multiple parallel infrared light beams; The vacuum sample chamber is arranged on the optical path of the focused infrared light and is used to accommodate the sample to be tested. The infrared light can enter the vacuum sample chamber.

2. The micro-area infrared probe according to claim 1, characterized in that: The Cassegrain prism comprises: A main prism, the infrared light reflected by the reflector can be incident from the main prism; A first secondary prism is disposed on one side of the main prism and is used to reflect the infrared light focused and reflected by the main prism onto the sample to be tested in the vacuum sample chamber; The second sub-prism is symmetrically arranged on the other side of the main prism relative to the first sub-prism, and is used to reflect the infrared light reflected by the sample to be tested onto the main prism; the infrared light is reflected by the main prism and emitted parallel to the incident direction.

3. The micro-area infrared probe according to claim 2, characterized in that: The angle between the infrared light reflected by the first sub-prism and the normal line of the sample surface is 45°-60°.

4. The micro-area infrared probe according to claim 1, characterized in that: The focal length of the Cassegrain prism is 10 mm-20 mm.

5. The micro-area infrared probe according to claim 1, characterized in that: It also includes an infrared detector, which is arranged on the optical path of the emitted infrared light and is used to receive the infrared light reflected by the sample.

6. The micro-area infrared probe according to claim 5, characterized in that: It also includes a visible light source, which is coaxially arranged with the micro-area infrared light source; the optical path of the visible light emitted by the visible light source is the same as the optical path of the infrared light.

7. The micro-area infrared probe according to claim 6, characterized in that: It also includes a CCD camera, which is arranged on the optical path of the visible light and is used to observe the sample to be tested.

8. The micro-area infrared probe according to claim 7, characterized in that: A spectrometer is provided between the CCD camera and the infrared detector for separating the infrared light from the visible light.

9. The micro-area infrared probe according to claim 8, characterized in that: A knife-edge aperture is arranged between the Cassegrain prism and the beam splitter.

10. The micro-area infrared probe according to claim 1, characterized in that: The vacuum sample chamber comprises: Ultra-high vacuum chamber; an infrared optical window, disposed on the ultra-high vacuum cavity, for introducing the infrared light; and The four-axis sample holder can translate the sample to be tested in three directions: X-axis, Y-axis and Z-axis, and rotate the sample to be tested.

Images