Solar blind ultraviolet detector and preparation method and application thereof

Abstract

The invention discloses a solar blind ultraviolet detector and a preparation method and application thereof, and belongs to the technical field of semiconductor photoelectric detectors. The preparation method comprises the following steps: sequentially epitaxially growing a GaN buffer layer, an AlGaN insertion layer and a GaN transmission layer on the surface of a substrate; etching the upper surface of the GaN transmission layer to obtain a groove; depositing a first insulating layer in the groove; epitaxially growing a Ga2O3 absorption layer on the GaN transmission layer and the first insulating layer to enable the Ga2O3 absorption layer to cover the first insulating layer; etching a part of the Ga2O3 absorption layer until a part of the upper surface of the GaN transmission layer is exposed; an anode electrode is arranged on the upper surface of the exposed part of the GaN transmission layer; and a metal layer and a cathode electrode are manufactured on the upper surface of the Ga2O3 absorption layer, so that the cathode electrode is in direct contact with the upper surface of the Ga2O3 absorption layer. According to the invention, the problem that light current is reduced due to accumulation of photo-generated holes in gallium oxide as an absorption layer is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor photoelectric detectors, and more specifically, to a solar-blind ultraviolet detector and a preparation method and application thereof. Background Art

[0002] When solar radiation passes through the ozone layer, the light in the 200nm to 280nm band will be absorbed by the ozone layer and cannot reach the surface, so this band is called the solar-blind band. Due to the low background noise, solar-blind detectors have been widely used in missile warning, astronomy, chemical and biological analysis, space communications, and fire monitoring. Gallium oxide (Ga2O3) is a fourth-generation wide-bandgap semiconductor material with a bandgap width of up to 4.8eV, and the corresponding maximum cutoff absorption wavelength is about 254nm. Therefore, Ga2O3 has a natural solar-blind detection characteristic. However, the defect density of gallium oxide film is high, which will cause a large dark current, resulting in a decrease in the signal-to-noise ratio and sensitivity of the detector. In addition, the carrier mobility of gallium oxide is low, and the photogenerated carriers are prone to local crowding, resulting in poor photoelectric conversion efficiency, which in turn causes the performance parameters such as the detector's responsiveness and external quantum efficiency to decrease.

[0003] In order to improve the performance of Ga2O3-based ultraviolet detectors, Chinese patent CN 114220878 A discloses a Ga2O3 / GaN solar-blind ultraviolet detector with a carrier transport layer and a preparation method thereof. The patent uses the electric field formed by the Schottky contact between metal and gallium oxide to push photogenerated electrons from the Ga2O3 / absorption layer with many defects into the GaN transport layer with few defects, thereby achieving the purpose of improving the detector's responsiveness and response speed. However, the above-mentioned prior art does not solve the problem that gallium oxide as an absorption layer causes photogenerated holes to accumulate therein, thereby reducing the photocurrent. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the existing day-blind ultraviolet detectors using gallium oxide as an absorption layer, which easily lead to the accumulation of photogenerated holes and thus reduce the photocurrent. A preparation method of a day-blind ultraviolet detector is provided, in which a cathode electrode in direct contact is arranged on the Ga2O3 absorption layer to achieve effective collection of photogenerated holes, thereby preventing the photogenerated holes from accumulating in the Ga2O3 absorption layer and recombining with electrons. At the same time, the electric field formed by the contact between the Ga2O3 absorption layer and the metal layer is used to transport carriers to the GaN transmission layer, thereby improving the electron transport efficiency and thus improving the photocurrent of the device.

[0005] Another object of the present invention is to provide a solar-blind ultraviolet detector.

[0006] Another object of the present invention is to provide an application of a solar-blind ultraviolet detector.

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] A method for preparing a solar-blind ultraviolet detector comprises the following steps:

[0009] S1. epitaxially growing a GaN buffer layer, an AlGaN insertion layer and a GaN transmission layer on the substrate surface in sequence;

[0010] S2. Etching the upper surface of the GaN transport layer to obtain a groove;

[0011] S3. Depositing a first insulating layer in the groove;

[0012] S4. epitaxially growing a Ga2O3 absorption layer on the GaN transmission layer and the first insulating layer, so that the Ga2O3 absorption layer covers the first insulating layer;

[0013] S5. Etching a portion of the Ga2O3 absorption layer to expose a portion of the upper surface of the GaN transmission layer;

[0014] S6. An anode electrode is arranged on the upper surface of the exposed portion of the GaN transmission layer; a metal layer and a cathode electrode are fabricated on the upper surface of the Ga2O3 absorption layer so that the cathode electrode is in direct contact with the upper surface of the Ga2O3 absorption layer.

[0015] The invention discloses a solar-blind ultraviolet detector with a photogenerated hole release effect. The detector has a Ga2O3 / GaN / AlGaN / GaN structure. A cathode electrode in direct contact is arranged on a Ga2O3 absorption layer to achieve effective collection of photogenerated holes, thereby preventing the photogenerated holes from accumulating in the Ga2O3 absorption layer and recombining with electrons. At the same time, an electric field formed by the contact between the Ga2O3 absorption layer and a metal layer is used to transport carriers to a GaN transmission layer with high electron mobility, thereby improving the electron transport efficiency and thus improving the photocurrent of the device.

[0016] Moreover, in the solar-blind ultraviolet detector of the present invention, negative polarization charges exist at the interface between the AlGaN insertion layer and the GaN transport layer. A groove region is formed on the upper surface of the GaN transport layer. The depletion region formed in the groove region under no light conditions can pinch off the electron transport channel to reduce the dark current.

[0017] The operating process in the preparation method of the solar-blind ultraviolet detector in the present invention is possessed by technicians in this technical field. The raw materials involved can be obtained through general channels. The process is simple and reliable, has strong repeatability, and has low production cost. It is suitable for industrial promotion and can be applied to the field of solar-blind ultraviolet detection.

[0018] Preferably, step S6 comprises the following steps:

[0019] An anode electrode is arranged on the upper surface of the exposed portion of the GaN transport layer;

[0020] Epitaxially growing a second insulating layer on the upper surface of the exposed portion of the GaN transmission layer and the upper surface of the Ga2O3 absorption layer;

[0021] forming a metal layer on the upper surface of the second insulating layer;

[0022] A cathode electrode is fabricated on the upper surface of the Ga2O3 absorption layer, so that the cathode electrode is in direct contact with the upper surface of the Ga2O3 absorption layer.

[0023] Among them, the function of the second insulating layer is to regulate the electric field in the Ga2O3 absorption layer and protect the Ga2O3 absorption layer from physical damage and chemical corrosion, thereby extending the service life of the detector.

[0024] Preferably, the projected area of ​​the Ga2O3 absorption layer is 20% to 80% of the upper surface area of ​​the GaN transmission layer.

[0025] The projected area of ​​the Ga2O3 absorption layer is related to the responsivity of the solar-blind ultraviolet detector. A larger projected area can absorb more light, thus having a higher response characteristic in the solar-blind band.

[0026] Preferably, the projected area of ​​the groove in the GaN transmission layer is 5% to 30% of the surface area of ​​the GaN transmission layer.

[0027] The projection area of ​​the groove in the GaN transmission layer is related to the dark current of the solar-blind ultraviolet detector. The larger the projection area, the larger the depletion region formed, and more electrons are depleted.

[0028] Preferably, the depth of the groove is 0.001 μm to 1 μm, the thickness of the first insulating layer is 0.001 μm to 0.5 μm, and the thickness of the first insulating layer is less than or equal to the depth of the groove.

[0029] Preferably, the projected area of ​​the metal layer is 20% to 80% of the upper surface area of ​​the Ga2O3 absorption layer.

[0030] The projection area of ​​the metal layer is related to the photocurrent of the solar-blind ultraviolet detector. The larger the projection area, the larger the depletion region formed by the metal layer and the Ga2O3 absorption layer, so that more electrons are pushed into the GaN transmission layer.

[0031] Preferably, the projected area of ​​the second insulating layer is 20% to 80% of the upper surface area of ​​the Ga2O3 absorption layer, and the thickness of the second insulating layer is 0.001 μm to 0.5 μm.

[0032] The projection area of ​​the second insulating layer is related to the photocurrent of the day-blind ultraviolet detector. The larger the projection area, the larger the area of ​​the corresponding deposited metal layer. At the same time, the depletion region formed with the Ga2O3 absorption layer is larger, so that more electrons are pushed into the GaN transmission layer.

[0033] Preferably, the thickness of the GaN buffer layer is 1 μm to 3 μm, the thickness of the AlGaN insertion layer is 0.005 μm to 0.5 μm, the thickness of the GaN transmission layer is 0.1 μm to 5 μm, the thickness of the Ga2O3 absorption layer is 0.001 μm to 0.5 μm, and the thickness of the metal layer is 1 nm to 20 nm.

[0034] In a specific embodiment,

[0035] The material of the substrate is specifically silicon wafer, sapphire or diamond.

[0036] The AlGaN insertion layer is made of non-intentionally doped AlGaN material, and the Al component ranges from 0.1 to 0.5.

[0037] The GaN transmission layer is made of non-intentionally doped GaN material.

[0038] The material of the first insulating layer is one or more of Si3N4, SiO2, Al2O3, HfO2, Ta2O5, AlN, and LiF.

[0039] The material of the Ga2O3 absorption layer is undoped (unintentionally doped) Ga2O3.

[0040] The cathode electrode, the anode electrode and the metal layer are made of the same or different materials, and are all made of Au, Ag, Ni, ITO, Ti or Pt.

[0041] The material of the metal layer may be a stack of several metals, for example, a stack of nickel and gold, that is, nickel layer-gold layer or nickel layer-gold layer-nickel layer-gold layer.

[0042] The material of the second insulating layer is one or more of undoped SiO2, Al2O3, Si3N4, HfO2, Ta2O5, AlN, LiF, diamond or PMMA.

[0043] The patterns of the metal layer and the second insulating layer are strip, rectangle, circle, ring or matrix distribution, and the shapes of the second insulating layer and the metal layer correspond one to one.

[0044] In step S1, a GaN buffer layer, an AlGaN insertion layer and a GaN transmission layer are epitaxially grown in sequence on the surface of the substrate by a thin film epitaxial growth technique of deposition, evaporation or sputtering.

[0045] In step S2, the groove is prepared by photolithography and dry etching processes.

[0046] In step S3, the first insulating layer is prepared by thin film epitaxial growth technology of deposition, evaporation or sputtering, photolithography and wet etching.

[0047] In step S4, the Ga2O3 absorption layer is prepared by thin film epitaxial growth technology of deposition, evaporation or sputtering.

[0048] In step S5, a portion of the Ga2O3 absorption layer is photolithographically and dry-etched to expose a portion of the upper surface of the GaN transmission layer.

[0049] In step S6, the anode electrode, the cathode electrode and the metal layer are prepared by photolithography and electron beam evaporation.

[0050] In step S6, the second insulating layer is prepared by a thin film epitaxial growth technique such as deposition, evaporation or sputtering.

[0051] In step S6, the second insulating layer is patterned by photolithography and wet etching.

[0052] The present invention also protects the solar-blind ultraviolet detector prepared by the method for preparing the solar-blind ultraviolet detector described in any one of the above items.

[0053] The present invention also protects the application of the above-mentioned solar-blind ultraviolet detector in fire monitoring, missile early warning, astronomy, chemistry, biological analysis, and space communication.

[0054] Solar-blind UV detectors can be used in fire detection because they are not easily disturbed by sunlight and have a strong ability to process weak signals. Solar-blind UV flame detectors can capture flames in a timely and accurate manner to compensate for the lag of infrared flame detectors and prevent fires.

[0055] Solar-blind ultraviolet detectors can be used in missile early warning because they are not easily interfered by sunlight and have high sensitivity and strong anti-interference capabilities. "Solar-blind" ultraviolet missile early warning detectors can capture ultraviolet radiation released from missile tail flames in a timely and accurate manner, making up for the shortcomings of other early warning systems, improving the accuracy and response speed of early warning, and thus effectively preventing the occurrence of missile threats.

[0056] Solar-blind ultraviolet detectors can be used in astronomy. They can capture ultraviolet radiation from distant galaxies and celestial bodies in a timely and accurate manner, helping scientists reveal the mysteries of the universe.

[0057] Solar-blind UV detectors can be used in chemistry because of their high sensitivity to specific UV bands, which can be used to detect and analyze chemicals. For example, it can be used to detect harmful chemicals in the environment, such as ozone and nitrogen oxides, which have characteristic absorption in specific UV bands.

[0058] Solar-blind UV detectors can be used in biological analysis and can detect the luminescence or absorption characteristics of biomolecules in specific UV bands, which is crucial for analyzing the structure and function of biomolecules.

[0059] Solar-blind ultraviolet detectors can be used in space communications. Because they have extremely low background noise and ultra-high signal-to-noise ratio in ultraviolet communications, solar-blind ultraviolet detectors can achieve highly confidential data transmission in space communications, prevent information from being eavesdropped, and ensure the security of communications.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] The invention discloses a solar-blind ultraviolet detector with a Ga2O3 / GaN / AlGaN / GaN structure. The detector realizes effective collection of photogenerated holes by arranging a cathode electrode in direct contact with a Ga2O3 absorption layer, thereby preventing the photogenerated holes from accumulating in the Ga2O3 absorption layer and recombining with electrons. At the same time, the electric field formed by the contact between the Ga2O3 absorption layer and the metal layer is used to transport carriers to a GaN transmission layer with high electron mobility, thereby improving the electron transport efficiency and thus improving the photocurrent of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is one of the schematic diagrams of the solar-blind ultraviolet detector according to Example 1 of the present invention.

[0063] Figure 2 This is the second schematic diagram of the solar-blind ultraviolet detector according to Example 1 of the present invention.

[0064] Figure 3 Schematic diagram of a solar-blind ultraviolet detector according to Example 2 of the present invention.

[0065] Figure 4 Schematic diagram of the solar-blind ultraviolet detector of comparative example 1 of the present invention.

[0066] Figure 5 It is the concentration of photogenerated holes in the gallium oxide absorption layer of the solar-blind ultraviolet detector of Example 1 of the present invention and Comparative Example 1.

[0067] Figure 6 It is the photocurrent of the solar-blind ultraviolet detector of Example 1 of the present invention and Comparative Example 1.

[0068] Among them, 101. substrate, 102. GaN buffer layer, 103. AlGaN insertion layer, 104. GaN transmission layer, 105. first insulating layer, 106. Ga2O3 absorption layer, 107. metal layer, 108. cathode electrode, 109. anode electrode, 110. second insulating layer. DETAILED DESCRIPTION

[0069] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0070] 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.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0072] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0074] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0075] Example 1

[0076] like Figures 1-2 As shown, a solar-blind ultraviolet detector, the preparation method comprises the following steps:

[0077] S1. epitaxially growing a GaN buffer layer 102, an AlGaN insertion layer 103 and a GaN transport layer 104 on the surface of the substrate 101 in sequence;

[0078] S2. Etching the upper surface of the middle portion of the GaN transport layer 104 to obtain a groove;

[0079] S3. Depositing a first insulating layer 105 in the groove;

[0080] S4. epitaxially growing a Ga2O3 absorption layer 106 on the GaN transmission layer 104 and the first insulating layer 105, so that the Ga2O3 absorption layer 106 completely covers the first insulating layer 105;

[0081] S5. Etching the right portion of the Ga2O3 absorption layer 106 to expose a portion of the upper surface of the GaN transmission layer 104;

[0082] S6. An anode electrode 109 is disposed on the upper surface of the exposed portion of the GaN transport layer 104 ; a metal layer 107 and a cathode electrode 108 are fabricated on the upper surface of the Ga2O3 absorption layer 106 , so that the cathode electrode 108 is in direct contact with the upper surface of the Ga2O3 absorption layer 106 .

[0083] The upper surface of the middle portion of the Ga 2 O 3 absorption layer 106 is covered with a patterned metal layer 107 , and the cathode electrode 108 is on the left side of the upper surface of the Ga 2 O 3 absorption layer 106 .

[0084] Specifically,

[0085] In step S1, in a MOCVD reactor, a GaN buffer layer 102, an AlGaN insertion layer 103 and a GaN transport layer 104 are epitaxially grown in sequence on the surface of a substrate 101 at a growth temperature of 1050° C. and a gas pressure of 50 mbar.

[0086] In step S2, the groove is prepared by photolithography and dry etching processes.

[0087] In step S3, the first insulating layer 105 is epitaxially grown in a PECVD reactor at a growth temperature of 300° C. and a gas pressure of 0.5 mbar. The first insulating layer 105 on the surface of the GaN transport layer 104 is removed by photolithography and wet etching to prepare the first insulating layer 105 in the groove.

[0088] In step S4, the Ga2O3 absorption layer is obtained by epitaxial growth in an ALD reactor at a growth temperature of 250°C.

[0089] In step S5, a mesa is produced by photolithography and dry etching a portion of the Ga2O3 absorption layer 106 until a portion of the upper surface of the GaN transmission layer 104 is exposed.

[0090] In step S6, the anode electrode, the cathode electrode and the metal layer are prepared by photolithography technology and electron beam evaporation process.

[0091] The Ga2O3 absorption layer 106 covers the first insulating layer 105 .

[0092] The projected area of ​​the Ga 2 O 3 absorption layer 106 is 60% of the upper surface area of ​​the GaN transmission layer 104 .

[0093] The projected area of ​​the groove in the GaN transport layer 104 is 20% of the surface area of ​​the GaN transport layer 104 .

[0094] The depth of the grooves was 0.05 μm.

[0095] The projected area of ​​the metal layer 107 is 80% of the upper surface area of ​​the Ga2O3 absorption layer 106.

[0096] Specifically,

[0097] The substrate 101 is sapphire.

[0098] The thickness of the GaN buffer layer 102 is 1.8 μm.

[0099] The material of the AlGaN insertion layer 103 is undoped Al 0.2 Ga 0.8 N, the thickness of the AlGaN insertion layer 103 is 0.01 μm.

[0100] The GaN transmission layer 104 is undoped GaN, and the thickness of the GaN transmission layer 104 is 0.2 μm.

[0101] The material of the first insulating layer 105 is SiO 2 , and the thickness of the first insulating layer 105 is 0.05 μm. The thickness of the first insulating layer 105 is equal to the depth of the groove.

[0102] The material of the Ga2O3 absorption layer 106 is undoped Ga2O3, and the thickness of the Ga2O3 absorption layer 106 is 0.2 μm.

[0103] The material of the metal layer 107 is a stacked layer of a metal Ni layer and a metal Au layer; the thickness of the metal layer 107 is 110 nm. The pattern of the metal layer 107 is a rectangle.

[0104] The cathode electrode 108 and the anode electrode 109 are both made of Au.

[0105] Example 2

[0106] like Figure 3 As shown, a solar-blind ultraviolet detector, the preparation method is different from that of Example 1 in that:

[0107] Step S6. Disposing an anode electrode 109 on the upper surface of the exposed portion of the GaN transport layer 104;

[0108] Epitaxially growing a second insulating layer 110 on the upper surface of the GaN transmission layer 104 and the upper surface of the Ga2O3 absorption layer 106 that are partially exposed;

[0109] A metal layer 107 is formed on the upper surface of the second insulating layer 110;

[0110] A cathode electrode 108 is fabricated on the upper surface of the Ga 2 O 3 absorption layer 106 , so that the cathode electrode 108 is in direct contact with the upper surface of the Ga 2 O 3 absorption layer 106 .

[0111] The upper surface and right side surface of the middle part of the Ga2O3 absorption layer 106 are covered with a second insulating layer 110 , a patterned metal layer 107 is formed on the second insulating layer 110 , and the cathode electrode 108 is on the left side of the upper surface of the Ga2O3 absorption layer 106 .

[0112] Specifically,

[0113] In step S6, in an ALD reactor, a SiO2 insulating layer is deposited on the exposed upper surface of the GaN transmission layer 104 and the Ga2O3 absorption layer 106, and a second insulating layer 110 is produced on the Ga2O3 absorption layer 106 by wet etching technology, wherein a portion of the second insulating layer 110 covers the upper surface of the Ga2O3 absorption layer 106, and another portion of the second insulating layer 110 completely covers the side wall of the Ga2O3 absorption layer 106.

[0114] By using photolithography and electron beam evaporation, an anode electrode 109 is fabricated on the exposed surface of the GaN transmission layer 104, and a cathode electrode 108 is fabricated on the Ga2O3 absorption layer 106 not covered by the second insulating layer 110; a patterned metal layer 107 is fabricated on the upper surface of the second insulating layer.

[0115] The second insulating layer 110 has a rectangular shape.

[0116] The material of the second insulating layer is SiO 2 . The projection area of ​​the second insulating layer 110 is 20% to 80% of the upper surface area of ​​the Ga 2 O 3 absorption layer 106 . The thickness of the second insulating layer 110 is 0.05 μm.

[0117] The thickness of the GaN buffer layer 102 is 1.8 μm.

[0118] The thickness of the GaN transmission layer 104 is 6 μm.

[0119] Example 3

[0120] A solar-blind ultraviolet detector, which differs from Example 1 in that the cathode electrode is made of Ti.

[0121] Example 4

[0122] A solar-blind ultraviolet detector, which differs from Example 1 in that:

[0123] The projected area of ​​the Ga2O3 absorption layer 106 is 20% of the upper surface area of ​​the GaN transmission layer 104 .

[0124] The projected area of ​​the groove in the GaN transport layer 104 is 5% of the surface area of ​​the GaN transport layer 104 .

[0125] The depth of the groove is 0.001 μm, and the thickness of the first insulating layer 105 is 0.001 μm.

[0126] The projected area of ​​the metal layer 107 is 20% of the upper surface area of ​​the Ga2O3 absorption layer 106.

[0127] The projected area of ​​the second insulating layer 110 is 20% of the upper surface area of ​​the Ga2O3 absorption layer 106, and the thickness of the second insulating layer 110 is 0.001 μm.

[0128] The thickness of the GaN buffer layer 102 is 1 μm, the thickness of the AlGaN insertion layer 103 is 0.005 μm, the thickness of the GaN transmission layer 104 is 0.1 μm, the thickness of the Ga2O3 absorption layer 106 is 0.001 μm, and the thickness of the metal layer 107 is 1 nm.

[0129] Example 5

[0130] A solar-blind ultraviolet detector, which differs from Example 1 in that:

[0131] The projected area of ​​the Ga 2 O 3 absorption layer 106 is 80% of the upper surface area of ​​the GaN transmission layer 104 .

[0132] The projected area of ​​the groove in the GaN transport layer 104 is 30% of the surface area of ​​the GaN transport layer 104 .

[0133] The depth of the groove is 1 μm, and the thickness of the first insulating layer 105 is 0.5 μm.

[0134] The projected area of ​​the metal layer 107 is 80% of the upper surface area of ​​the Ga2O3 absorption layer 106.

[0135] The projection area of ​​the second insulating layer 110 is 80% of the upper surface area of ​​the Ga2O3 absorption layer 106, and the thickness of the second insulating layer 110 is 0.5 μm.

[0136] The thickness of the GaN buffer layer 102 is 3 μm, the thickness of the AlGaN insertion layer 103 is 0.5 μm, the thickness of the GaN transmission layer 104 is 5 μm, the thickness of the Ga2O3 absorption layer 106 is 0.5 μm, and the thickness of the metal layer 107 is 20 nm.

[0137] Comparative Example 1

[0138] like Figure 4 As shown, a solar-blind ultraviolet detector has the following structure:

[0139] From bottom to top, there are substrate 101, GaN buffer layer 102, AlGaN insertion layer 103, GaN transmission layer 104. A groove is opened in the middle of the transmission layer 104, and a first insulating layer 105 is deposited in the groove. The middle of the GaN transmission layer 104 and the first insulating layer 105 are covered with a Ga2O3 absorption layer 106, and a patterned metal layer 107 is formed on the Ga2O3 absorption layer 106. A cathode electrode 108 and an anode electrode 109 are respectively located on the surface of the GaN transmission layer 104.

[0140] The materials and structures of each layer are the same as those in Example 1 and will not be described again here.

[0141] Results

[0142] The relevant performance tests were performed on the solar-blind ultraviolet detectors of the above embodiments and comparative examples:

[0143] (1) Photogenerated hole concentration in the gallium oxide absorption layer: The test method is TCAD simulation software. The unit is cm -3 .

[0144] The specific test results of Example 1 and Comparative Example 1 are shown in Tables 1 and Figure 5 As shown:

[0145] Table 1

[0146]

[0147] (2) Photocurrent: In the voltage range of 1 to 6 V, the test method is TCAD simulation. The unit is A / cm 2 .

[0148] The specific test results of Example 1 and Comparative Example 1 are shown in Tables 2 and Figure 6 As shown:

[0149] Table 2

[0150] Voltage (V) 1 2 3 4 5 6 Example 1 <![CDATA[2.30*10 -3 ]]> <![CDATA[2.41*10 -3 ]]> <![CDATA[2.43*10 -3 ]]> <![CDATA[2.45*10 -3 ]]> <![CDATA[2.46*10 -3 ]]> <![CDATA[2.48*10 -3 ]]> Comparative Example 1 <![CDATA[2.25*10 -3 ]]> <![CDATA[2.34*10 -3 ]]> <![CDATA[2.36*10 -3 ]]> <![CDATA[2.38*10 -3 ]]> <![CDATA[2.40*10 -3 ]]> <![CDATA[2.44*10 -3 ]]>

[0151] It can be seen from the above results that compared with Comparative Example 1, the photocurrent of the solar-blind ultraviolet detector of the present invention is significantly improved, and the concentration of photogenerated holes in the Ga2O3 absorption layer in the solar-blind ultraviolet detector of the present invention is lower, indicating that in the solar-blind ultraviolet detector of the present invention, the cathode electrode in direct contact with the Ga2O3 absorption layer can effectively collect photogenerated holes, making it easier for photogenerated electrons to participate in downward transport.

[0152] The photocurrent and dark current of the solar-blind ultraviolet detector of the present invention are related to the materials and dimensions of the GaN buffer layer, the AlGaN insertion layer, the GaN transmission layer, the first insulating layer, the Ga2O3 absorption layer, the patterned metal layer and the second insulating layer (if any).

[0153] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a solar-blind ultraviolet detector, characterized in that: The steps include: S1. epitaxially growing a GaN buffer layer (102), an AlGaN insertion layer (103) and a GaN transport layer (104) in sequence on the surface of a substrate (101); S2. etching the upper surface of the GaN transport layer (104) to obtain a groove; S3. depositing a first insulating layer (105) in the groove; S4. epitaxially growing a Ga2O3 absorption layer (106) on the GaN transmission layer (104) and the first insulating layer (105), so that the Ga2O3 absorption layer (106) covers the first insulating layer (105); S5. etching a portion of the Ga2O3 absorption layer (106) until a portion of the upper surface of the GaN transport layer (104) is exposed; S6. An anode electrode (109) is arranged on the upper surface of the exposed portion of the GaN transmission layer (104); a metal layer (107) and a cathode electrode (108) are fabricated on the upper surface of the Ga2O3 absorption layer (106), so that the cathode electrode (108) is in direct contact with the upper surface of the Ga2O3 absorption layer (106).

2. The method for preparing a solar-blind ultraviolet detector according to claim 1, characterized in that: The step S6 comprises the following steps: An anode electrode (109) is arranged on the upper surface of the exposed portion of the GaN transport layer (104); epitaxially growing a second insulating layer (110) on the upper surface of the GaN transmission layer (104) and the upper surface of the Ga2O3 absorption layer (106) that are partially exposed; Manufacturing a metal layer (107) on the upper surface of the second insulating layer (110); A cathode electrode (108) is fabricated on the upper surface of the Ga2O3 absorption layer (106), so that the cathode electrode (108) is in direct contact with the upper surface of the Ga2O3 absorption layer (106).

3. The method for preparing a solar-blind ultraviolet detector according to claim 1, characterized in that: The projected area of ​​the Ga2O3 absorption layer (106) is 20% to 80% of the upper surface area of ​​the GaN transmission layer (104).

4. The method for preparing a solar-blind ultraviolet detector according to claim 1, characterized in that: The projection area of ​​the groove in the GaN transmission layer (104) is 5% to 30% of the surface area of ​​the GaN transmission layer (104).

5. The method for preparing a solar-blind ultraviolet detector according to claim 1, characterized in that: The depth of the groove is 0.001 μm to 1 μm, the thickness of the first insulating layer (105) is 0.001 μm to 0.5 μm, and the thickness of the first insulating layer (105) is less than or equal to the depth of the groove.

6. The method for preparing a solar-blind ultraviolet detector according to claim 1, characterized in that: The projection area of ​​the metal layer (107) is 20% to 80% of the upper surface area of ​​the Ga2O3 absorption layer (106).

7. The method for preparing a solar-blind ultraviolet detector according to claim 2, characterized in that: The projection area of ​​the second insulating layer (110) is 20% to 80% of the upper surface area of ​​the Ga2O3 absorption layer (106), and the thickness of the second insulating layer (110) is 0.001 μm to 0.5 μm.

8. The method for preparing a solar-blind ultraviolet detector according to any one of claims 1 to 7, characterized in that: The thickness of the GaN buffer layer (102) is 1 μm to 3 μm, the thickness of the AlGaN insertion layer (103) is 0.005 μm to 0.5 μm, the thickness of the GaN transmission layer (104) is 0.1 μm to 5 μm, the thickness of the Ga2O3 absorption layer (106) is 0.001 μm to 0.5 μm, and the thickness of the metal layer (107) is 1 nm to 20 nm.

9. A solar-blind ultraviolet detector prepared by the method for preparing a solar-blind ultraviolet detector according to any one of claims 1 to 8.

10. Application of the solar-blind ultraviolet detector described in claim 9 in fire monitoring, missile early warning, astronomy, chemistry, biological analysis, and space communication.

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