Boron nitride nanosheet stacked neutron detector and preparation method thereof

Abstract

The invention belongs to the technical field of semiconductor device preparation, and discloses a boron nitride nanosheet stacked neutron detector and a preparation method thereof. The boron nitride nanosheet stacked neutron detector comprises a ceramic substrate, an ohmic contact lower electrode, quartz, an etching region, boron nitride nanosheets and an ohmic contact upper electrode, the surface of the ceramic substrate is rectangular or square; the ohmic contact lower electrode is positioned on the upper surface of the ceramic substrate; the quartz is positioned on the upper surface of the ohmic contact lower electrode; the etching region is a region, which needs to be etched, of quartz; the boron nitride nanosheet is positioned in the etching region; and the ohmic contact upper electrode is positioned on the upper surface of the quartz and boron nitride nanosheet. The invention designs a boron nitride nanosheet stacking device structure, and provides an effective, simple and low-cost process manufacturing technology, so that the preparation problem of the boron nitride neutron detector is solved, and the development of the boron nitride neutron detector with a relatively large area is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor device preparation, and relates to a method for preparing a neutron detector with a boron nitride nanosheet stacking structure. Background Art

[0002] Boron nitride is a wide-bandgap semiconductor material. Compared with silicon materials, it has excellent properties such as high melting point, high critical displacement threshold energy, high breakdown electric field strength and high thermal conductivity, which makes it show broad application potential in high-power devices, high-temperature devices and radiation detection. In the field of neutron detection, silicon materials are inefficient in detecting thermal neutrons, have poor energy resolution, and have weak radiation tolerance. In contrast, boron nitride materials can not only serve as neutron conversion layers, but also collect and transmit carriers; especially because the neutron capture cross section of boron-10 is extremely high (3840 barns), boron nitride has become an ideal material for manufacturing neutron detectors.

[0003] With the continuous progress of nuclear science and technology, the development trend of radiation detectors is moving towards a larger detection area and lower manufacturing cost. At present, the preparation technology of boron nitride (BN) materials mainly includes methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). However, based on the current technology, the preparation of BN materials with a sufficiently large area and thickness faces certain challenges. To overcome this problem, the present invention proposes a neutron detector preparation technology based on BN nanosheet stacking. This technology uses low-cost BN nanosheets as the main raw material, and uses its unique stacking structure to significantly reduce the material cost and realize the production of large-area detectors. In addition, this technology simplifies the traditional preparation process, avoids complex thin film deposition and fine processing steps, thereby greatly reducing the difficulty of operation and production costs. By optimizing the stacking method and groove design of the nanosheets, the present invention further improves the sensitivity and resolution of the detector, making it have broad application prospects in the field of nuclear science and technology. Compared with other preparation methods, the advantages of the present invention are: 1. No BN film deposition equipment is required, and the cost is controllable; 2. The operation is simple; 3. It is easy to achieve a large detection area; 4. By selecting appropriate nanosheets and groove sizes, the vertical arrangement of nanosheets in the grooves is achieved, mainly utilizing the anisotropic characteristics of carrier transport in boron nitride materials. Therefore, the present invention innovatively proposes a low-cost, large-area neutron detector preparation method based on boron nitride nanosheet stacking. Summary of the invention

[0004] The purpose of the present invention is to propose a method for preparing a boron nitride nanosheet stacked neutron detector in response to the many problems and technical difficulties encountered in the process of preparing the above-mentioned boron nitride neutron detection device.

[0005] The technical solution of the present invention:

[0006] A boron nitride nanosheet stacked neutron detector comprises a ceramic substrate 1, an ohmic contact lower electrode 2, a quartz 3, an etched region 4, a boron nitride nanosheet 5 and an ohmic contact upper electrode 6;

[0007] The surface shape of the ceramic substrate 1 is rectangular or square;

[0008] The ohmic contact lower electrode 2 is located on the upper surface of the ceramic substrate 1;

[0009] The quartz 3 is located on the upper surface of the ohmic contact lower electrode 2;

[0010] The etching area 4 is the area of ​​the quartz 3 that needs to be etched;

[0011] The boron nitride nanosheet 5 is located inside the etching area 4;

[0012] The ohmic contact upper electrode 6 is located on the upper surface of the quartz 3 and the boron nitride nanosheet 5;

[0013] The device body is composed of quartz 3, etching area 4, and boron nitride nanosheets 5.

[0014] A method for preparing a boron nitride nanosheet stacked neutron detector, comprising the following steps:

[0015] Step 1: Prepare an ohmic contact lower electrode 2 on the upper surface of a ceramic substrate 1 by a deposition or growth method;

[0016] Step 2: using a laser etching method to etch a rectangular groove-shaped through hole on the quartz surface;

[0017] Step 3: placing the etched quartz sheet on the upper surface of the ceramic substrate 1 on which the ohmic contact lower electrode 2 is deposited, so that the quartz sheet contacts the ohmic contact lower electrode 2, and bonding the two by hot pressing;

[0018] Step 4: Use a 10 μm-1 mm standard sieve to screen out the boron nitride nanosheets 5 whose diameter is larger than the groove width;

[0019] Step 5: Mix the screened boron nitride nanosheets 5 with the ethanol solution to prepare a suspension, and then drip it into the rectangular groove-shaped through hole for filling, and fill it multiple times until it is flush with the surface of the quartz 3;

[0020] Step 6: Place the filled device on a heating table to dry;

[0021] Step 8: Prepare an ohmic contact upper electrode 6 on the surface of the quartz 3 and the boron nitride nanosheet 5 by a deposition or growth method;

[0022] Step 9: Prepare the lead electrode 7 on the ohmic contact lower electrode 2 by using a deposition or growth method in combination with a mask;

[0023] Step 10: Prepare the lead electrode 7 on the surface of the ohmic contact upper electrode 6 by using a deposition or growth method in combination with a mask.

[0024] The deposition methods include thermal evaporation, electron beam evaporation, magnetron sputtering, laser pulse deposition, and atomic layer deposition.

[0025] The thickness of the ohmic contact lower electrode 2 and the ohmic contact upper electrode 6 is 10 nm to 10 μm.

[0026] Beneficial effects of the present invention: The present invention designs a boron nitride nanosheet stacking device structure and proposes an effective, simple and low-cost process manufacturing technology, which solves the preparation problem of boron nitride neutron detectors and realizes the development of larger-area boron nitride neutron detection devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the top-down structure of quartz after etching.

[0028] Figure 2 This is a schematic diagram of the cross-sectional structure of quartz after etching.

[0029] Figure 3 It is a top view schematic diagram of the quartz plate and the ceramic substrate with the surface growth electrode bonded together.

[0030] Figure 4 Schematic diagram of the cross section of the device after filling with boron nitride nanosheets.

[0031] Figure 5 This is a schematic diagram of the cross-section of the structure of a neutron detection device composed of stacked boron nitride nanosheets.

[0032] Figure 6 This is a top-down schematic diagram of the structure of a neutron detection device made of stacked boron nitride nanosheets.

[0033] Figure 7 This is a statistical diagram of thermal neutron counts obtained in Example 1 under a bias voltage of 80V.

[0034] Figure 8 This is a diagram of the neutron pulse signal collected in Example 1 under a bias voltage of 80V.

[0035] In the figure: 1 ceramic substrate, 2 ohmic contact lower electrode, 3 quartz, 4 etching area, 5 boron nitride nanosheet, 6 ohmic contact upper electrode, 7 cathode electrode. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is further described below in conjunction with the technical scheme and the accompanying drawings.

[0037] Example 1

[0038] Example

[0039] A method for preparing a boron nitride nanosheet stacked neutron detector comprises the following steps:

[0040] Step 1: Prepare a ceramic substrate with a length of 4 cm, a width of 2 cm, and a thickness of 2 mm;

[0041] Step 2: Using magnetron sputtering method to evaporate a 10 μm thick tin gold electrode on the surface of the ceramic substrate;

[0042] Step 3: A groove-shaped through hole with a width of 80 μm and a length of 10 mm is etched on a quartz sheet with a size of 2×2 cm and a thickness of 100 μm by laser etching;

[0043] Step 4: Place the etched quartz sheet on the upper surface of the ceramic substrate with the electrode evaporated, so that it contacts the ohmic contact lower electrode 2, and place it in an annealing furnace for annealing at 280°C in a nitrogen environment for 5 minutes to bond the two;

[0044] Step 5: Use a standard sieve with a pore size of 80 μm to screen nanosheets with a diameter of more than 80 μm;

[0045] Step 6: Mix 5 g of the screened boron nitride nanosheets with 300 ml of ethanol solution to make a suspension, then drip it into the groove for filling, and fill it multiple times;

[0046] Step 7: Place the filled device on a heating table to dry (50°C, 10 min);

[0047] Step 8: Using an electron beam deposition method, a titanium / gold electrode with a thickness of 5 μm is evaporated on the upper surface of the groove in combination with a mask;

[0048] Step 9: Using an electron beam deposition method in combination with a mask, a gold lead electrode 7 with a diameter of 2 mm and a thickness of 1 μm is prepared on the surface of the ohmic contact lower electrode and the ohmic contact upper electrode.

[0049] The neutron test data of Example 1 is as follows: Figure 7 and Figure 8 As shown, the test is based on the spallation neutron source test platform, and the average emitted neutron energy is 0.025eV; Figure 7 The thermal neutron counts obtained in Example 1 under a bias voltage of 80 V, with a test time of 300 seconds; Figure 8 This is the neutron pulse signal collected in Example 1 under a bias voltage of 80 V, which proves that the nanosheet stack neutron detector prepared in Example 1 has good neutron detection capability.

Claims

1. A boron nitride nanosheet stack neutron detector, characterized in that: The boron nitride nanosheet stacked neutron detector comprises a ceramic substrate (1), an ohmic contact lower electrode (2), quartz (3), an etched region (4), a boron nitride nanosheet (5) and an ohmic contact upper electrode (6); The ohmic contact lower electrode (2) is located on the upper surface of the ceramic substrate (1); The quartz (3) is located on the upper surface of the ohmic contact lower electrode (2); The etching area (4) is the area of ​​the quartz (3) that needs to be etched away; The boron nitride nanosheet (5) is located inside the etching area (4); The ohmic contact upper electrode (6) is located on the upper surface of the quartz (3) and the boron nitride nanosheet (5).

2. A method for preparing a boron nitride nanosheet stacked neutron detector, characterized in that: Here are the steps: Step 1: preparing an ohmic contact lower electrode (2) on the upper surface of a ceramic substrate (1); Step 2: Etching a rectangular groove-shaped through hole on the quartz; Step 3: placing the etched quartz plate on the upper surface of the ohmic contact lower electrode (2), and bonding the two by hot pressing; Step 4: After mixing the boron nitride nanosheets (5) with the ethanol solution to form a suspension, the suspension is dripped into the rectangular groove-shaped through hole for filling, and the suspension is filled multiple times until the suspension is flush with the surface of the quartz (3); Step 5: Place the filled device on a heating table to dry; Step 8: preparing an ohmic contact upper electrode (6) on the surface of the quartz (3) and the boron nitride nanosheet (5); Step 9: Prepare a lead electrode (7) on the ohmic contact lower electrode (2) in combination with a mask; Step 10: Prepare a lead electrode (7) on the surface of the ohmic contact upper electrode (6) in combination with a mask.

3. The preparation method according to claim 2, characterized in that: The boron nitride nanosheets (5) are screened out using a 10 μm-1 mm standard sieve and have a diameter greater than the groove width.

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