Infrared detector based on mixed structure

Abstract

The utility model provides an infrared detector based on a mixed structure. The infrared detector comprises a substrate, a first electrode, a first photosensitive layer, a mask layer, a second photosensitive layer and a second electrode which are stacked in sequence, the first electrode is a vertical structure device, and the second electrode is a horizontal structure device; the first electrode is provided with a reflecting surface, and the first photosensitive layer is in a strip shape with a recess; the utilization of the surface plasmon enhancement effect of the first electrode and the second electrode is facilitated; the first electrode is used as a reflecting surface, so that the absorption efficiency of incident light is improved; the long-strip-shaped first photosensitive layer with the concave part is beneficial to multiple times of reflection and absorption of incident light, and the sensitivity and the accuracy of the infrared detector are improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of sensors, and in particular to an infrared detector based on a hybrid structure. Background Art

[0002] Current infrared detectors are made based on photosensitive films, but the photosensitive films of infrared detectors are usually of a single structure, the photosensitive films of infrared detectors are of a vertical structure, or the photosensitive films of infrared detectors are of a horizontal structure; in addition, the growth area of ​​the photosensitive films of infrared detectors is relatively large, and it is easy to produce more defects or dislocation density, which makes the infrared detector absorb insufficient light and reduces the sensitivity of the infrared detector. Utility Model Content

[0003] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0004] The purpose of the present application is to solve one of the technical problems existing in the related art to at least a certain extent. The embodiment of the present application provides an infrared detector based on a hybrid structure, which improves sensitivity and accuracy.

[0005] An embodiment of the present application is an infrared detector based on a hybrid structure, comprising: a substrate, a first electrode, a first photosensitive layer, a mask layer, a second photosensitive layer and a second electrode stacked in sequence; the first electrode is a vertical structure device, and the second electrode is a horizontal structure device; the first electrode is provided with a reflective surface, and the first photosensitive layer is a long strip with a depression.

[0006] According to some embodiments of the present application, the width of the first photosensitive layer ranges from 50 nanometers to 900 nanometers, and the length of the first photosensitive layer ranges from 500 nanometers to 70,000 nanometers.

[0007] According to some embodiments of the present application, the first photosensitive layer and the second photosensitive layer are made of gallium arsenide.

[0008] According to some embodiments of the present application, the mask layer is in the shape of a long strip, the width of the mask layer ranges from 2 micrometers to 20 micrometers, and the length of the mask layer ranges from 600 micrometers to 70,000 micrometers.

[0009] According to some embodiments of the present application, the mask layer is made of silicon dioxide.

[0010] According to some embodiments of the present application, the second electrode is an interdigitated electrode.

[0011] According to some embodiments of the present application, a width of the second electrode ranges from 50 nanometers to 300 nanometers, and a gap distance between adjacent interdigitated fingers of the second electrode ranges from 200 nanometers to 1000 nanometers.

[0012] According to some embodiments of the present application, the substrate and the first electrode protrude from the first photosensitive layer, the mask layer, and the second photosensitive layer on the first side of the infrared detector.

[0013] According to some embodiments of the present application, the substrate, the first electrode and the first photosensitive layer protrude from the mask layer and the second photosensitive layer on a second side of the infrared detector; wherein the second side is an opposite side to the first side.

[0014] According to certain embodiments of the present application, the second electrode includes a first upper electrode and a second upper electrode; the first upper electrode includes a first interdigitated piece and the first palm piece, and a plurality of the first interdigitated pieces are connected to the first palm piece; the second upper electrode includes a second interdigitated piece and the second palm piece, and a plurality of the second interdigitated pieces are connected to the second palm piece; the first interdigitated pieces and the second interdigitated pieces are interlaced with each other; the first palm piece is located on the second photosensitive layer, and the second palm piece is located on the protruding portions of the first photosensitive layer and the second photosensitive layer.

[0015] The above scheme has at least the following beneficial effects: using the first electrode as a vertical structure device and the second electrode as a horizontal structure device is conducive to utilizing the surface plasmon enhancement effect of the first electrode and the second electrode; using the first electrode as a reflective surface improves the absorption efficiency of incident light; the first photosensitive layer with a concave long strip is conducive to multiple reflections and absorption of incident light, thereby improving the sensitivity and accuracy of the infrared detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0017] Figure 1 is a structural diagram of an infrared detector based on a hybrid structure provided in an embodiment of the present application;

[0018] Figure 2 This is another structural diagram of an infrared detector based on a hybrid structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] It should be noted that, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first", "second", etc. in the specification, claims or the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0021] Current infrared detectors are made based on photosensitive films, but the photosensitive films of infrared detectors are usually of a single structure, the photosensitive films of infrared detectors are of a vertical structure, or the photosensitive films of infrared detectors are of a horizontal structure; in addition, the growth area of ​​the photosensitive films of infrared detectors is relatively large, and it is easy to produce more defects or dislocation density, which makes the infrared detector absorb insufficient light and reduces the sensitivity of the infrared detector.

[0022] In order to solve the above problems, an embodiment of the present application provides an infrared detector based on a hybrid structure.

[0023] Reference Figure 1 and Figure 2 The infrared detector includes: a substrate 100, a first electrode 200, a first photosensitive layer 300, a mask layer 400, a second photosensitive layer 500 and a second electrode stacked in sequence; the first electrode 200 is a vertical structure device, and the second electrode is a horizontal structure device; the first electrode 200 is provided with a reflective surface, and the first photosensitive layer 300 is a long strip with a depression.

[0024] In this embodiment, the first electrode 200 is used as a vertical structure device, and the second electrode is used as a horizontal structure device, which is beneficial to utilizing the surface plasmon enhancement effect of the first electrode 200 and the second electrode; the first electrode 200 is used as a reflective surface to improve the absorption efficiency of incident light; the first photosensitive layer 300 with a concave long strip is beneficial to multiple reflections and absorption of incident light, thereby improving the sensitivity and accuracy of the infrared detector.

[0025] The hybrid structure combining the vertical structure and the horizontal structure also fully utilizes the area of ​​the mask layer 400 without causing a reduction in the light absorption area.

[0026] The substrate 100 and the first electrode 200 protrude from the first photosensitive layer 300, the mask layer 400 and the second photosensitive layer 500 on the first side of the infrared detector. In addition, the substrate 100 and the first electrode 200 are aligned in the first side direction of the infrared detector, and the first photosensitive layer 300, the mask layer 400 and the second photosensitive layer 500 are aligned in the first side direction of the infrared detector, which is convenient for production.

[0027] The substrate 100, the first electrode 200 and the first photosensitive layer 300 protrude from the mask layer 400 and the second photosensitive layer 500 on the second side of the infrared detector. In addition, the substrate 100, the first electrode 200 and the first photosensitive layer 300 are aligned on the second side of the infrared detector, and the mask layer 400 and the second photosensitive layer 500 are aligned on the second side of the infrared detector, which is convenient for production.

[0028] The second side of the infrared detector is the opposite side of the first side of the infrared detector. For example, the first side of the infrared detector is the left side of the infrared detector, and the second side of the infrared detector is the right side of the infrared detector.

[0029] The substrate 100 is made of silicon. Of course, in other embodiments, the substrate 100 can also be made of other types of materials according to actual production requirements.

[0030] The first electrode 200 and the second electrode are made of gold. Of course, in other embodiments, the first electrode 200 and the second electrode can also be made of other types of materials with high conductivity, such as copper, etc., according to actual production requirements.

[0031] The first photosensitive layer 300 and the second photosensitive layer 500 are made of gallium arsenide. Gallium arsenide is a black-gray solid with a melting point of 1238°C. It can stably exist in the air below 600°C and is not corroded by non-oxidizing acids. The refractive index of gallium arsenide is 3.57. Gallium arsenide has excellent optical properties, which are mainly reflected in its nanowire crystal structure and photoluminescence spectrum. Of course, in other embodiments, according to actual production requirements, the first photosensitive layer 300 and the second photosensitive layer 500 can also be made of other materials with good optical properties, such as cadmium selenide.

[0032] The mask layer 400 is made of silicon dioxide. Of course, in other embodiments, the mask layer 400 can also be made of other types of materials according to actual production requirements.

[0033] The first photosensitive layer 300 is in the shape of a strip, and the size of the first photosensitive layer 300 is in the nanometer level. The width of the first photosensitive layer 300 ranges from 50 nanometers to 900 nanometers, and the length of the first photosensitive layer 300 ranges from 500 nanometers to 70,000 nanometers. For example, the width of the first photosensitive layer 300 is 100 nanometers, and the length of the first photosensitive layer 300 is 1,000 nanometers. Of course, in other embodiments, the length and width of the first photosensitive layer 300 can be set according to actual production requirements.

[0034] The mask layer 400 is in the shape of a long strip, and the size of the mask layer 400 is in the micron level. The width of the mask layer 400 ranges from 2 microns to 20 microns, and the length of the mask layer 400 ranges from 600 microns to 70000 microns. For example, the width of the mask layer 400 is 10 microns, and the length of the mask layer 400 is 1000 microns. Of course, in other embodiments, the width and width of the mask layer 400 can be set according to actual production requirements.

[0035] The first electrode 200 and the second electrode are both nanometer-sized, and their surface plasmon enhancement effect can be further utilized to improve the performance of the device.

[0036] The second electrode is a forked electrode. The forked electrode is an electrode with a periodic pattern in a finger-like or comb-like surface. The width of the second electrode ranges from 50 nanometers to 300 nanometers, and the gap distance between adjacent forked fingers of the second electrode ranges from 200 nanometers to 1000 nanometers. For example, the width of the second electrode ranges from 100 nanometers, and the gap distance between adjacent forked fingers of the second electrode is 500 nanometers. Of course, in other embodiments, the number of pairs of forked electrode pairs, the forked finger width, the gap distance between adjacent forked fingers, and the thickness of the forked electrode can be set according to actual production requirements.

[0037] The second electrode includes a first upper electrode 610 and a second upper electrode 620; the first upper electrode 610 includes a first interdigital piece 611 and a first palm piece 612, and a plurality of first interdigital pieces 611 are connected to the first palm piece 612; the second upper electrode 620 includes a second interdigital piece 621 and a second palm piece 622, and a plurality of second interdigital pieces 621 are connected to the second palm piece 622; the first interdigital pieces 611 and the second interdigital pieces 621 are interlaced with each other.

[0038] It can be understood that, for the interdigital electrode, a plurality of longitudinal interdigital elements are connected to a transverse strip, and the strip is the palm element of the interdigital electrode.

[0039] The first palm piece 612 is located on the second photosensitive layer 500; the second palm piece 622 is located on the protruding parts of the first photosensitive layer 300 and the second photosensitive layer 500, and there is a connecting part between the second palm piece 622 located on the first photosensitive layer 300 and the second palm piece 622 located on the protruding part of the second photosensitive layer 500 on the first photosensitive layer 300, and the connecting part covers the side surfaces of the second photosensitive layer 500 and the mask layer 400.

[0040] The infrared detector based on the hybrid structure can be prepared according to the following preparation method steps.

[0041] Step S1, epitaxially growing a thin film of the first electrode 200 on the substrate 100;

[0042] Step S2, sputtering a mask layer 400 on the thin film of the first electrode 200 by magnetron sputtering;

[0043] Step S3, applying photoresist on the mask layer 400, and using the mask layer 400 to etch the thin film of the first electrode 200 to obtain the region of the first electrode 200;

[0044] Step S4, removing the photoresist, cleaning and drying, forming a mask layer 400 of micrometer-scale strips and a first electrode 200 of nanometer-scale strips;

[0045] Step S5, transferring the sample prepared in step S4 to a magnetron sputtering device, setting the sputtering power of the magnetron sputtering device to 80 W and the argon pressure to 0.1 Pa, sputtering for 2 hours at room temperature, and then annealing at 750° C. for 2 hours in high vacuum, forming a first photosensitive layer 300 on the first electrode 200, and forming a second photosensitive layer 500 on the mask layer 400;

[0046] Step S6, vapor-depositing the sample prepared in step S5 in a vapor deposition machine to form a second electrode on the surface of the sample, and performing alloying treatment on the second electrode to form an interdigitated electrode;

[0047] Step S7: using laser etching to expose the first electrode 200.

[0048] Through micro-region confinement, it is beneficial to release the growth stress of the crystal and improve the quality of the film.

[0049] The following is a specific description with reference to Embodiment 1 and Embodiment 2.

[0050] Example 1

[0051] The Au film of the first electrode 200 is epitaxially grown on the Si substrate 100, and the thickness of the Au film is 30 nanometers. SiO2 with a thickness of 300 nanometers is sputtered on the Au film by magnetron sputtering. 2A photoresist is applied to the mask layer 400, and the Au region where the nano-strips grow is etched on the Au film using the mask layer 400. The photoresist is removed, and the film is cleaned and dried to obtain a micron-strip SiO 2 and nano-strips of Au; the nano-strips are 300 nanometers wide and 1000 nanometers long; the micron-strips of SiO 2 The width is 2 microns and the length is 1000 nanometers. The sample is transferred to a magnetron sputtering device, sputtered for 2 hours under the conditions of argon pressure of 0.1Pa, sputtering power of 80W and room temperature, and then annealed at 750℃ in situ for 2 hours in high vacuum, so as to form a first photosensitive layer 300 on the first electrode 200, and a second photosensitive layer 500 on the mask layer 400. The first photosensitive layer 300 and the second photosensitive layer 500 are GaAs photosensitive layers with a thickness of 100 nanometers. In the evaporator, the surface of the sample is evaporated to obtain a 100-nanometer second electrode Au electrode, and alloying treatment is performed to prepare a micron-long nano-interdigitated electrode to obtain a horizontal structure infrared detector. The Au film is exposed by laser etching as the lower electrode of the vertical structure infrared detector. So far, an infrared detector with a metal-semiconductor-metal structure mixed with a horizontal structure and a vertical structure is obtained.

[0052] Example 2

[0053] The Au film of the first electrode 200 is epitaxially grown on the Si substrate 100, and the thickness of the Au film is 200 nanometers. SiO2 with a thickness of 500 nanometers is sputtered on the Au film by magnetron sputtering. 2 A photoresist is applied to the mask layer 400, and the Au region where the nano-strips grow is etched on the Au film using the mask layer 400. The photoresist is removed, and the film is cleaned and dried to obtain a micron-strip SiO 2 and nano-strips of Au; the nano-strips are 900 nanometers wide and 5000 nanometers long; the micron-strips of SiO 2 The width is 2 microns and the length is 5000 nanometers. The sample is transferred to a magnetron sputtering device, sputtered for 4 hours under the conditions of argon pressure of 1Pa, sputtering power of 80W and room temperature, and then annealed at 750℃ in situ for 2 hours in a high vacuum, so as to form a first photosensitive layer 300 on the first electrode 200, and a second photosensitive layer 500 on the mask layer 400. The first photosensitive layer 300 and the second photosensitive layer 500 are GaAs photosensitive layers with a thickness of 300 nanometers. In the evaporator, the surface of the sample is evaporated to obtain a 300-nanometer second electrode Au electrode, and alloying treatment is performed to prepare a micron-long nano-interdigitated electrode to obtain a horizontal structure infrared detector. The Au film is exposed by laser etching as the lower electrode of the vertical structure infrared detector. So far, an infrared detector with a metal-semiconductor-metal structure mixed with a horizontal structure and a vertical structure is obtained.

[0054] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the embodiments. Technical personnel familiar with the field can make various equivalent modifications or substitutions without violating the spirit of the present application. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. An infrared detector based on a hybrid structure, characterized in that: include: A substrate, a first electrode, a first photosensitive layer, a mask layer, a second photosensitive layer and a second electrode are stacked in sequence; the first electrode is a vertical structure device, and the second electrode is a horizontal structure device; the first electrode is provided with a reflective surface, and the first photosensitive layer is a long strip with a depression.

2. The infrared detector based on a hybrid structure according to claim 1, characterized in that: The width of the first photosensitive layer ranges from 50 nanometers to 900 nanometers, and the length of the first photosensitive layer ranges from 500 nanometers to 70,000 nanometers.

3. The infrared detector based on a hybrid structure according to claim 1, characterized in that: The first photosensitive layer and the second photosensitive layer are made of gallium arsenide.

4. The infrared detector based on a hybrid structure according to claim 1, characterized in that: The mask layer is in the shape of a long strip, the width of the mask layer ranges from 2 micrometers to 20 micrometers, and the length of the mask layer ranges from 600 micrometers to 70,000 micrometers.

5. The infrared detector based on a hybrid structure according to claim 1, characterized in that: The mask layer is made of silicon dioxide.

6. The infrared detector based on a hybrid structure according to claim 1, characterized in that: The second electrode is an interdigitated electrode.

7. The infrared detector based on a hybrid structure according to claim 6, characterized in that: The width of the second electrode is in a range of 50 nanometers to 300 nanometers, and the gap distance between adjacent interdigits of the second electrode is in a range of 200 nanometers to 1000 nanometers.

8. The infrared detector based on a hybrid structure according to claim 1, characterized in that: The substrate and the first electrode protrude from the first photosensitive layer, the mask layer, and the second photosensitive layer at a first side of the infrared detector.

9. The infrared detector based on a hybrid structure according to claim 8, characterized in that: The substrate, the first electrode and the first photosensitive layer protrude from the mask layer and the second photosensitive layer on a second side of the infrared detector; wherein the second side is an opposite side to the first side.

10. The infrared detector based on a hybrid structure according to claim 9, characterized in that: The second electrode includes a first upper electrode and a second upper electrode; the first upper electrode includes a first interdigitated piece and a first palm piece, and a plurality of the first interdigitated pieces are connected to the first palm piece; the second upper electrode includes a second interdigitated piece and a second palm piece, and a plurality of the second interdigitated pieces are connected to the second palm piece; the first interdigitated pieces and the second interdigitated pieces are interlaced with each other; the first palm piece is located on the second photosensitive layer, and the second palm piece is located on the protruding portions of the first photosensitive layer and the second photosensitive layer.

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