Solar-blind ultraviolet photoelectric detector array based on gallium oxide and nickel oxide heterojunction and preparation method of solar-blind ultraviolet photoelectric detector array

Abstract

The invention provides a solar-blind ultraviolet photoelectric detector array based on gallium oxide and nickel oxide heterojunction, which comprises a single crystal Ga2O3 substrate, a plurality of array type Ga2O3 mesas are etched on the surface of the single crystal Ga2O3 substrate, and silicon oxide is filled among the Ga2O3 mesas; the NiO thin film covers one side of the upper surface of each Ga2O3 mesa, and the NiO thin film and the Ga2O3 mesa form a light absorption layer; the interdigital electrode structures are respectively arranged on the upper surface of the Ga2O3 table board and the upper surface of the NiO thin film; the electrode interconnection structure is arranged on the silicon oxide and comprises a row interconnection structure and a column interconnection structure, the row interconnection structure is used for connecting the first electrode groups of each row of Ga2O3 mesa in the array, and the column interconnection structure is used for connecting the second electrode groups of each column of Ga2O3 mesa in the array; and the packaging layer is arranged on the upper surfaces of the Ga2O3 mesa, the NiO thin film, the interdigital electrode structure and the electrode interconnection structure, and a connecting window of the electrode interconnection structure is exposed. The detector works at reverse bias voltage, and can obtain large photoelectric response.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor device technology, and more specifically, to a solar-blind ultraviolet photodetector array based on a gallium oxide and nickel oxide heterojunction and a preparation method thereof. Background Art

[0002] Solar-blind UV photodetectors, due to their solar-blind nature, can detect UV light with high sensitivity in atmospheric environments. They can maintain detection accuracy and stability even in strong surface light conditions, leading to their widespread application in environmental monitoring, industrial production, agricultural conservation, and medical imaging. Wide-bandgap semiconductor materials are often used in the fabrication of solar-blind UV photodetectors. Ga2O3, as an ultra-wide-bandgap material (4.2-4.9 eV), effectively absorbs solar-blind UV light. It exhibits excellent thermal stability, a high breakdown voltage, high responsivity, and a rapid response speed, making it an ideal material for solar-blind UV photodetectors.

[0003] Compared to other ultra-wide-bandgap materials, Ga2O3 can be grown as single crystals using the VB method. Current preparation techniques are becoming increasingly mature, making it viable for large-scale production. β-phase Ga2O3 is the most stable and can survive in atmospheric environments. The material itself contains numerous oxygen vacancies and gallium ions, which generate electrons. Therefore, gallium oxide is an n-type semiconductor, exhibiting a fast response speed. However, the valence band of Ga2O3's band structure prevents efficient hole conduction, making it difficult to fabricate p-type Ga2O3. NiO, a naturally occurring p-type semiconductor with a wide bandgap (3.6-4.0 eV), exhibits a small lattice mismatch with Ga2O3. Therefore, we chose to fabricate a heterojunction of Ga2O3 and NiO to fabricate a pn-junction photodetector. The band shift created by the heterojunction of Ga2O3 and NiO facilitates carrier separation. Both materials possess wide band gaps, resulting in a low electron-hole recombination rate and improved carrier mobility.

[0004] In summary, the Ga2O3 / NiO heterojunction photodetector has high response speed, stability and responsiveness, can quickly and accurately detect and convert solar-blind ultraviolet light signals, and has good application prospects. Summary of the Invention

[0005] In view of this, the present disclosure provides a solar-blind ultraviolet photodetector array based on a heterojunction of gallium oxide and nickel oxide.

[0006] One aspect of the present disclosure provides a solar-blind ultraviolet photodetector array based on a heterojunction of gallium oxide and nickel oxide, comprising: a single-crystal Ga2O3 substrate, with multiple array-type Ga2O3 mesas etched on the surface, and silicon oxide filled between the Ga2O3 mesas; a NiO film, covering one side of the upper surface of each of the Ga2O3 mesas, and forming a light absorption layer together with the Ga2O3 mesas; an interdigitated electrode structure, respectively provided on the upper surface of the Ga2O3 mesas and the upper surface of the NiO film; an electrode interconnection structure, provided on the silicon oxide, comprising a row interconnection structure and a column interconnection structure, the row interconnection structure being used to connect the first electrode group of the Ga2O3 mesas in each row of the array, and the column interconnection structure being used to connect the second electrode group of the Ga2O3 mesas in each column of the array; and an encapsulation layer, provided on the upper surfaces of the Ga2O3 mesas, the NiO film, the interdigitated electrode structure, and the electrode interconnection structure, exposing a connection window of the electrode interconnection structure.

[0007] According to an embodiment of the present disclosure, the single crystal Ga2O3 substrate includes a (010) plane substrate, a (001) plane substrate, a (100) plane substrate and a (-201) plane substrate.

[0008] According to an embodiment of the present disclosure, the work function of the electrode material of the interdigitated electrode structure matches the heterojunction formed by the Ga2O3 mesa and the NiO thin film.

[0009] According to an embodiment of the present disclosure, the intersection region between the row interconnection structure and the column interconnection structure is isolated by silicon oxide.

[0010] According to an embodiment of the present disclosure, the spacing between the Ga2O3 mesas is equal.

[0011] According to an embodiment of the present disclosure, at the connection between the electrode interconnection structure and the interdigital electrode structure, the area of ​​the electrode interconnection structure is larger than the area of ​​the interdigital electrode structure.

[0012] On the other hand, the present disclosure provides a method for preparing a solar-blind ultraviolet photodetector array based on a heterojunction of gallium oxide and nickel oxide, comprising: magnetron sputtering a NiO film on a single-crystal Ga2O3 substrate; etching the single-crystal Ga2O3 substrate using an inductively coupled plasma technique to form an array-type mesa Ga2O3 covered with a NiO film; etching the NiO film on one side of the Ga2O3 mesa; depositing silicon oxide to the same depth as the Ga2O3 mesa, and etching away the silicon oxide on the Ga2O3 mesa to expose the mesa; soaking the single-crystal Ga2O3 substrate in a chemical solvent, and repairing etching damage to the mesa surface by wet etching; preparing an interdigitated electrode structure on the Ga2O3 mesa and the NiO film, and depositing metal on the silicon oxide to form an electrode interconnection structure; depositing silicon oxide on the Ga2O3 mesa, the NiO film, the interdigitated electrode structure, and the electrode interconnection structure, and etching a connection window for the electrode interconnection structure to form an encapsulation layer.

[0013] At least one of the above technical solutions adopted in the embodiments of the present disclosure can achieve the following beneficial effects:

[0014] The disclosed embodiments provide a solar-blind ultraviolet photodetector array based on a Ga2O3 / NiO heterojunction. The ultra-wide-bandgap Ga2O3 material has high carrier mobility. After forming a heterojunction with NiO, the band shift accelerates carrier separation, resulting in a high detector response speed. Fabricated using semiconductor micro-nanotechnology, the Ga2O3 / NiO heterojunction detector array exhibits a fast response time and high responsiveness to solar-blind ultraviolet light, and holds great promise for applications in environmental monitoring, industrial production, agricultural protection, and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0016] Figure 1A Schematically shows a top view of a single Ga2O3 / NiO heterojunction solar-blind ultraviolet photodetector provided by an embodiment of the present disclosure;

[0017] Figure 1B Schematically shows a side view of a single Ga2O3 / NiO heterojunction solar-blind ultraviolet photodetector provided by an embodiment of the present disclosure;

[0018] Figure 2 The structure diagram of a 10×10 array of solar-blind ultraviolet photodetectors based on Ga2O3 / NiO heterojunction provided by an embodiment of the present disclosure is schematically shown;

[0019] Figure 3The flowchart of the method for preparing the solar-blind ultraviolet photodetector array based on gallium oxide provided by an embodiment of the present disclosure is schematically shown.

[0020] Description of reference numerals:

[0021] 11-Ga2O3 mesa; 12-NiO thin film; 13-interdigitated electrode structure; 14-column interconnection structure; 15-row interconnection structure; 16-silicon oxide; 17-encapsulation layer. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0023] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0024] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0025] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0026] The present disclosure provides a solar-blind ultraviolet photodetector array based on a gallium oxide and nickel oxide heterojunction, comprising: a single crystal Ga2O3 substrate, a plurality of array-type Ga2O3 mesas 11 etched on the surface ( Figure 1A and Figure 1B Each Ga2O3 mesa 11 is filled with silicon oxide 16. A single detector in the detector array is formed on each Ga2O3 mesa 11. Figure 1A and Figure 1BOne side of the upper surface of each Ga2O3 mesa 11 is covered with a NiO film 12, which constitutes a light absorption layer together with the Ga2O3 mesa 11; the surfaces of the Ga2O3 mesa 11 and the NiO film 12 are respectively provided with a first electrode group and a second electrode group of an interdigitated electrode structure 13; an electrode interconnection structure, an electrode interconnection structure is provided on the silicon oxide 16, and the electrode interconnection structure includes a row interconnection structure 15 and a column interconnection structure 14, wherein the row interconnection structure 15 is used to connect the first electrode group of each row of Ga2O3 mesas 11 in the array, and the column interconnection structure 14 is used to connect the second electrode group of each column of NiO film 12 in the array; an encapsulation layer 17 is provided on the upper surfaces of the Ga2O3 mesa 11, the NiO film 12, the interdigitated electrode structure 13 and the electrode interconnection structure, exposing a connection window of the electrode interconnection structure.

[0027] Optionally, the single crystal Ga2O3 substrate may be a (010) plane substrate, a (001) plane substrate, a (100) plane substrate or a (-201) plane substrate.

[0028] The work function of the electrode material of the interdigitated electrode structure 13 matches the heterojunction formed by the Ga2O3 mesa 11 and the NiO thin film 12. Suitable metal materials (such as titanium, platinum, titanium, and nickel) can be selected to form ohmic contacts with Ga2O3 and NiO, respectively. The contact resistance can be measured, and the metal with the lowest contact resistance can be selected to improve device performance.

[0029] The intersection area of ​​the row interconnection structure 15 and the column interconnection structure 14 is isolated by silicon oxide 16 to avoid short circuit.

[0030] The spacing between the Ga2O3 mesas 11 is equal to ensure the uniformity of the detector array.

[0031] At the connection between the electrode interconnection structure and the interdigital electrode structure 13 , the area of ​​the electrode interconnection structure is larger than the area of ​​the interdigital electrode structure 13 .

[0032] In this embodiment, the Ga2O3 / NiO heterojunction photodetector is responsive to light in the solar-blind ultraviolet band. The mesas 11, formed by ICP etching, are separated by silicon oxide 16, forming a light-absorbing layer. Before depositing the metal electrodes, the sample is soaked in a chemical solvent to repair the etched surface, ensuring better contact between the metal electrode and the semiconductor and preventing the introduction of defects due to etching that could affect device performance.

[0033] like Figure 2 As shown, in the embodiment of the present disclosure, taking a 10×10 array as an example, the devices form a photodetector array through a row and column interconnection structure, and 10 row electrodes and 10 column electrodes are respectively connected to the readout circuit, so that the electrical and photoelectric performance of all devices can be tested.

[0034] According to the disclosed embodiments, a solar-blind ultraviolet photodetector array based on a Ga2O3 / NiO heterojunction is constructed. Beta-phase gallium oxide, a fourth-generation semiconductor material with an ultra-wide bandgap and high thermal stability, forms a heterojunction with NiO to create a pn-junction photodetector with fast response speed, high responsivity, and low dark current. Therefore, photodetectors based on the Ga2O3 / NiO heterojunction can be used in various applications, including industrial production, medical imaging, and environmental monitoring.

[0035] Specifically, the present disclosure provides a method for testing the photoelectric performance of a solar-blind ultraviolet photodetector array based on gallium oxide, including:

[0036] The light source options include either a mercury lamp with a solar-blind UV filter or a 266nm laser. The first option provides a larger spot size, covering the entire array device, while the second offers a higher power and adjustable output, allowing for testing individual device responses to varying light powers.

[0037] Three performance tests are conducted on the device: 1. Electrical performance test: the IV curve of the device is tested to observe its rectification effect. Individual devices in the array are tested separately, and the uniformity of the electrical performance of the device is observed through statistical data. 2. Photoelectric performance test: the light response time, detection rate, and responsiveness of the device are tested using a semiconductor analyzer, and the uniformity of the photoelectric performance of the device is observed through statistical data. 3. Photocurrent mapping test: the light response mechanism of the photodetector is verified through the mapping current of the detector.

[0038] like Figure 3 As shown, another aspect of the present disclosure provides a method for preparing a solar-blind ultraviolet photodetector array based on a heterojunction of gallium oxide and nickel oxide, including S310 to S316.

[0039] S310, magnetron sputtering a NiO film 12 on a single crystal Ga2O3 substrate.

[0040] S311 , using inductively coupled plasma technology to etch the single crystal Ga2O3 substrate to form an array-type mesa Ga2O3 covered with a NiO film 12 .

[0041] S312 , etching the NiO film 12 on one side of the Ga 2 O 3 mesa 11 .

[0042] S313 , depositing silicon oxide 16 to the same depth as the Ga 2 O 3 mesas 11 , and etching away the silicon oxide 16 on the Ga 2 O 3 mesas 11 to expose the mesas 11 .

[0043] S314, soaking the single crystal Ga2O3 substrate in a chemical solvent, and repairing the etching damage on the surface of the mesa 11 by a wet etching method.

[0044] The sample is soaked in a chemical solvent to repair the etched surface, thereby improving the contact between the metal electrode and the semiconductor and preventing defects introduced by etching from affecting the performance of the device.

[0045] S315 , preparing an interdigitated electrode structure 13 on the Ga 2 O 3 mesa 11 and the NiO film 12 , and depositing metal on the silicon oxide 16 to form an electrode interconnection structure.

[0046] The electrodes are interdigitated electrode structures 13. After photolithography to form the electrode patterns at both ends, electron beam evaporation is performed to deposit a metal that matches the work function of the Ga2O3 / NiO heterojunction. The electrode patterns are then removed after lift-off. The row and column interconnect patterns are then photolithographically formed, and metal is deposited to form the interconnect structure.

[0047] The interdigital electrode structure 13 is made of a suitable metal material (titanium, platinum titanium, nickel gold, etc.) to form ohmic contacts with Ga2O3 and NiO respectively. The contact resistance is tested and the metal with the smallest contact resistance is selected.

[0048] S316, depositing silicon oxide 16 on the Ga2O3 mesa 11, the NiO film 12, the interdigitated electrode structure 13 and the electrode interconnection structure, and etching a connection window of the electrode interconnection structure to form a packaging layer.

[0049] The solar-blind ultraviolet photodetector array based on Ga2O3 / NiO is packaged with silicon oxide 16, which can ensure that the photodetector can be used for a long time in complex environments without affecting its performance.

[0050] The entire process flow of the preparation method provided by the embodiment of the present disclosure is simple, the array-type photodetector has higher accuracy in responding to day-blind ultraviolet light, and the performance of the device is stable after packaging, which is conducive to large-scale construction of devices to achieve batch production.

[0051] The above describes the embodiments of the present disclosure. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A solar-blind ultraviolet photodetector array based on a gallium oxide and nickel oxide heterojunction, comprising: A single crystal Ga2O3 substrate, with a plurality of array-type Ga2O3 mesas (11) etched on the surface, and silicon oxide (16) filled between the Ga2O3 mesas (11); A NiO film (12) covers one side of the upper surface of each Ga2O3 mesa (11) and forms a light absorption layer together with the Ga2O3 mesa (11); An interdigitated electrode structure (13), wherein a first electrode group and a second electrode group are arranged on the upper surface of the Ga2O3 table (11) and the upper surface of the NiO film (12); an electrode interconnection structure, provided on the silicon oxide (16), comprising a row interconnection structure (15) and a column interconnection structure 14, wherein the row interconnection structure (15) is used to connect the first electrode group of the Ga2O3 mesas (11) in each row of the array, and the column interconnection structure 14 is used to connect the second electrode group of the Ga2O3 mesas (11) in each column of the array; The encapsulation layer (17) is provided on the upper surfaces of the Ga2O3 table (11), the NiO film (12), the interdigitated electrode structure (13) and the electrode interconnection structure, exposing a connection window of the electrode interconnection structure.

2. The solar-blind ultraviolet photodetector array based on gallium oxide and nickel oxide heterojunction according to claim 1, wherein: The single crystal Ga2O3 substrate includes a (010) surface substrate, a (001) surface substrate, a (100) surface substrate and a (-201) surface substrate.

3. The solar-blind ultraviolet photodetector array based on gallium oxide and nickel oxide heterojunction according to claim 1, wherein: The work function of the electrode material of the interdigitated electrode structure (13) matches the heterojunction formed by the Ga2O3 table (11) and the NiO film (12).

4. The solar-blind ultraviolet photodetector array based on gallium oxide and nickel oxide heterojunction according to claim 1, wherein: The intersection area between the row interconnection structure (15) and the column interconnection structure 14 is isolated by silicon oxide (16).

5. The solar-blind ultraviolet photodetector array based on gallium oxide and nickel oxide heterojunction according to claim 1, wherein: The spacing between the Ga2O3 mesas (11) is equal.

6. The solar-blind ultraviolet photodetector array based on gallium oxide and nickel oxide heterojunction according to claim 1, wherein: At the connection between the electrode interconnection structure and the interdigital electrode structure (13), the area of ​​the electrode interconnection structure is larger than the area of ​​the interdigital electrode structure (13).

7. A method for preparing a solar-blind ultraviolet photodetector array based on a gallium oxide and nickel oxide heterojunction, comprising: Magnetron sputtering of NiO thin films on single crystal Ga2O3 substrates (12); Etching the single crystal Ga2O3 substrate using an inductively coupled plasma technique to form an array-type Ga2O3 mesa (11) covered with a NiO film (12); Etching the NiO film (12) on one side of the Ga2O3 table (11); Depositing silicon oxide (16) to the same depth as the Ga2O3 mesa (11), and etching away the silicon oxide (16) on the Ga2O3 mesa (11) to expose the mesa; soaking the single crystal Ga2O3 substrate in a chemical solvent and repairing the etching damage on the mesa surface by wet etching; preparing an interdigitated electrode structure (13) on the Ga2O3 table (11) and the NiO film (12), and depositing metal on the silicon oxide (16) to form an electrode interconnection structure; Silicon oxide (16) is deposited on the Ga2O3 table (11), the NiO film (12), the interdigitated electrode structure (13), and the electrode interconnection structure, and a connection window of the electrode interconnection structure is etched to form an encapsulation layer (17).

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