Zinc oxide / magnesium zinc oxide structure alpha particle detector and preparation method thereof

Abstract

The invention belongs to the technical field of semiconductor device preparation, and discloses a zinc oxide / magnesium zinc oxide alpha particle detector and a preparation method. The zinc oxide / magnesium-zinc-oxygen alpha particle detector comprises an aluminum oxide single crystal, a high-resistance magnesium-zinc-oxygen region, a hole conductive oxide layer region, a low-resistance zinc oxide region, an insulating layer, a collecting electrode and a gate electrode. The invention designs the structure of the alpha particle detector with the zinc oxide / magnesium zinc oxide structure, provides an effective and simple process manufacturing technology, solves the preparation problem of the alpha particle detector with the internal gain characteristic, and realizes the development of the novel alpha particle detector with the zinc oxide / magnesium zinc oxide structure.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device fabrication technology, and relates to a zinc oxide / magnesium zinc oxygen alpha particle detector and its fabrication method. Background Technology

[0002] In recent years, with the rapid development of nuclear energy development, space exploration, and high-energy physics experiments, the performance requirements for charged particle (such as alpha particles, beta particles, and protons) detectors have been increasing. Traditional gas detectors and scintillator detectors suffer from drawbacks such as large size and high energy consumption. While commercial silicon-based semiconductor detectors have high sensitivity, they face problems such as low radiation damage threshold and insufficient high-temperature stability. Therefore, charged particle detectors based on novel semiconductor materials are needed. Oxide semiconductor materials, such as zinc oxide (ZnO) and magnesium zinc oxide (MgZnO), have become ideal candidates for next-generation detectors due to their large band gap, intrinsic radiation resistance, and high-temperature stability. The main problems currently facing the development of oxide semiconductor alpha particle detectors are, firstly, the difficulty in controlling the electrical properties of oxide semiconductors, i.e., the materials often exhibit high or low resistance characteristics, resulting in a limited range of device types that can be fabricated; secondly, the carrier signal excited by alpha particles in the detector is relatively small, and due to the limited device structure, there is currently no structural design for signal amplification within the device, leading to a low signal-to-noise ratio.

[0003] Existing technologies employ single-layer Schottky structures or PN / PIN heterojunction vertical structures to fabricate detectors. These detectors can only collect electrons and holes generated by the signal source as response signals and lack detection amplification capabilities. This invention utilizes magnesium zinc oxide (MgZO) as the detection sensitive region. By controlling the ratio of magnesium and zinc atoms, the MgZO material exhibits high resistivity, with adjustable resistivity and mobility. Simultaneously, by designing a hole-conducting layer on the MgZO layer, free electrons in the MgZO are spontaneously depleted while ensuring sufficient mobility, further increasing resistivity and thus improving the device's collection electric field strength. Unlike vertical device structures, this invention designs a lateral current amplification mechanism. The amplified current transport channel is controlled through contact electrodes on the insulating layer of the MgZO. Electron-conducting zinc oxide regions are fabricated on both sides of the MgZO sensitive region, with electrodes on the same surface. When a voltage is applied, the response signal causes a transient decrease in resistivity near the MgZO region, achieving instantaneous output of the amplified current signal. Therefore, it can be seen that the present invention directly uses magnesium, zinc and oxygen as the detection sensitive area, which is simpler to prepare, solves the problem of controllable transmission path of amplified signal, and can realize high-quality amplification of detection signal, with outstanding technical innovation. Summary of the Invention

[0004] The purpose of this invention is to address the key issues that limit the further significant improvement of alpha particle detector performance by proposing an alpha particle detector based on a zinc oxide / magnesium zinc oxygen structure that can achieve high-quality gain of the detection signal and its fabrication method.

[0005] The technical solution of the present invention:

[0006] A zinc oxide / magnesium zinc oxygen structure alpha particle detector includes an aluminum oxide (Al2O3) single crystal 1 (thickness 360 μm) and a high-resistivity magnesium zinc oxygen (MgZnO) region 2 (thickness 10 μm-100 μm, resistivity 10). 6 -10 12 Ω·cm), hole conductivity (P-type, hole concentration 1×10 17 cm -3 -5×10 18 cm -3 Oxide layer region 3 (thickness 0.01μm-5μm), low-resistivity zinc oxide (ZnO) region 4 (thickness 10μm-100μm, resistivity 10) -1 -10 5 Ω·cm), insulating layer 5 (thickness 0.01μm-10μm), collecting electrode 6 (thickness 0.01μm-3μm) and gate electrode 7 (thickness 0.01μm-3μm).

[0007] The surface of the alumina single crystal 1 has a stepped structure from bottom to top, consisting of a high-resistivity magnesium zinc oxide (MgZnO) region 2 and an oxide layer region 3. On both sides of the stepped structure are low-resistivity zinc oxide (ZnO) regions 4, and the upper surface of the low-resistivity zinc oxide (ZnO) regions 4 is flush with the upper surface of the oxide layer region 3. Between the oxide layer region 3 and the low-resistivity zinc oxide (ZnO) regions 4 is an insulating layer 5, with openings in the insulating layer 5. The openings are for metal electrodes 6, and the collecting electrodes 6 are in contact with the low-resistivity zinc oxide (ZnO) regions 4. Above the oxide layer region 3 is a gate electrode 7, and the size of the gate electrode 7 is smaller than that of the oxide layer region 3.

[0008] Among them, the high-resistivity magnesium zinc oxide (MgZnO) region 2 is associated with hole conduction (P-type, hole concentration 1×10⁻⁶). 17 cm -3 -5×10 18 cm -3 The thickness ratio of oxide layer region 3 is between 1000:1 and 10:1.

[0009] The ratio of magnesium atoms to zinc atoms in MgZnO is between 1000:1 and 1:100.

[0010] A method for fabricating a zinc oxide / magnesium zinc oxygen structure alpha particle detector, comprising the following steps:

[0011] Step 1: Epitaxially grow a high-resistivity magnesium zinc oxide (MgZnO) region 2 and an oxide layer region 3 sequentially on alumina single crystal 1;

[0012] Step 2: After applying a photoresist mask, the ladder structure is fabricated using dry etching or wet etching.

[0013] Step 3: After cleaning, prepare low-resistivity zinc oxide (ZnO) regions 4 by physical deposition or chemical vapor deposition.

[0014] Step 4: Smooth the surface using chemical mechanical polishing or dry etching methods;

[0015] Step 5: Prepare insulating layer 5 using physical deposition method;

[0016] Step 6: Prepare a photoresist mask and use dry etching or wet etching to create grooves in the insulating layer 5 on the low-resistivity zinc oxide (ZnO) region 4 to expose part of the ZnO.

[0017] Step 7: Prepare a photoresist mask, and fabricate the metal electrode 6 using physical deposition and mask lift-off methods;

[0018] Step 8: Prepare a photoresist mask, and fabricate the gate electrode 7 by physical deposition and mask stripping.

[0019] The beneficial effects of this invention are as follows: This invention designs a zinc oxide / magnesium zinc oxide (MgZO) alpha particle detector structure, utilizing MgZO as the sensitive detection region. By controlling the ratio of magnesium and zinc atoms, the MgZO material exhibits high resistivity, and its resistivity and mobility are adjustable. Simultaneously, by designing a hole-conducting layer on the MgZO layer, the free electrons in the MgZO layer are spontaneously depleted while ensuring sufficient mobility, further increasing the resistivity and thus improving the collection electric field strength of the device. Unlike vertical device structures, this invention designs a lateral current amplification mechanism. The amplified current transport channel is controlled through the contact electrodes of the insulating layer on the MgZO layer. Electron-conducting zinc oxide regions are prepared on both sides of the MgZO sensitive region, and electrodes on the same surface are prepared. When a voltage is applied, the resistivity of the region near the MgZO region transiently decreases, achieving instantaneous output of the amplified current signal. Therefore, this invention proposes an effective and simple manufacturing process, solving the fabrication problem of oxide alpha particle detectors with internal gain characteristics, and realizing the development of a novel zinc oxide / MgZO alpha particle detector. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an alpha particle detector based on a zinc oxide / magnesium zinc oxygen structure.

[0021] In the figure: 1. Alumina single crystal; 2. High-resistivity magnesium zinc oxide region; 3. Hole-conducting (P-type) oxide layer region; 4. Low-resistivity zinc oxide (ZnO) region; 5. Insulating layer; 6. Collecting electrode; 7. Gate electrode. Detailed Implementation

[0022] The specific embodiments of the present invention will be further described below in conjunction with the technical solutions and accompanying drawings.

[0023] Example 1

[0024] A method for fabricating a zinc oxide / magnesium zinc oxygen structure alpha particle detector includes the following process steps:

[0025] Step 1: Epitaxially grow 10 μm thick alumina single crystal with a resistivity of 10 ohms on a 360 μm thick alumina single crystal. 6 High-resistivity magnesium-zinc-oxygen region 2 with Ω·cm and a thickness of 0.01μm and a hole concentration of 1×10 17 cm -3 Hole-conducting oxide layer region 3;

[0026] Step 2: After preparing the photoresist mask, the ladder structure is fabricated using dry etching.

[0027] Step 3: After cleaning, a low-resistivity zinc oxide region with a thickness of 10 μm and a resistivity of 1 Ω·cm is prepared by chemical vapor deposition 4;

[0028] Step 4: Use chemical mechanical polishing to smooth the surface and expose the upper surface of the stepped nickel oxide.

[0029] Step 5: Prepare a 0.01 μm thick silicon dioxide insulating layer 5 using magnetron sputtering;

[0030] Step 6: Prepare a photomask and use a wet etching method to create a groove in the insulating layer 5 on the low-resistivity zinc oxide region 4 to expose part of the ZnO;

[0031] Step 7: Prepare a photoresist mask, and fabricate an aluminum electrode 6 with a thickness of 0.01 μm by electron beam evaporation and mask stripping.

[0032] Step 8: Prepare a photoresist mask, and prepare an aluminum electrode 7 with a thickness of 0.01 μm by electron beam evaporation and mask stripping.

[0033] Example 2

[0034] A method for fabricating a zinc oxide / magnesium zinc oxygen structure alpha particle detector includes the following process steps:

[0035] Step 1: Epitaxially grow 100 μm thick alumina single crystal with a resistivity of 10⁻⁶ on a 360 μm thick alumina single crystal. 12High-resistivity magnesium-zinc-oxygen region 2 with Ω·cm and a thickness of 5μm and a hole concentration of 5×10 18 cm -3 Hole-conducting oxide layer region 3;

[0036] Step 2: After preparing the photoresist mask, the ladder structure is fabricated using dry etching.

[0037] Step 3: After cleaning, chemical vapor deposition is performed to prepare a film with a thickness of 100 μm and a resistivity of 10. 5 Low-resistivity zinc oxide region 4 with Ω·cm;

[0038] Step 4: Use chemical mechanical polishing to smooth the surface and expose the upper surface of the stepped nickel oxide.

[0039] Step 5: Prepare a 10 μm thick silicon dioxide insulating layer 5 using magnetron sputtering;

[0040] Step 6: Prepare a photomask and use a wet etching method to create a groove in the insulating layer 5 on the low-resistivity zinc oxide region 4 to expose part of the ZnO;

[0041] Step 7: Prepare a photoresist mask, and fabricate a 3μm thick aluminum electrode 6 by electron beam evaporation and mask stripping.

[0042] Step 8: Prepare a photoresist mask, and fabricate a 3μm thick aluminum electrode 7 by electron beam evaporation and mask stripping.

[0043] Example 3

[0044] A method for fabricating a zinc oxide / magnesium zinc oxygen structure alpha particle detector includes the following process steps:

[0045] Step 1: Epitaxially grow 20 μm thick alumina single crystal with a resistivity of 10⁻⁶ on a 360 μm thick alumina single crystal. 9 High-resistivity magnesium-zinc-oxygen region 2 with Ω·cm and a thickness of 1μm and a hole concentration of 1×10 18 cm -3 P-type nickel oxide layer 3;

[0046] Step 2: After applying a photoresist mask, the ladder structure is fabricated using dry etching.

[0047] Step 3: After cleaning, a low-resistivity zinc oxide region with a thickness of 20 μm and a resistivity of 10 Ω·cm is prepared by chemical vapor deposition 4;

[0048] Step 4: Use chemical mechanical polishing to smooth the surface and expose the upper surface of the stepped nickel oxide.

[0049] Step 5: Prepare a 1 μm thick silicon dioxide insulating layer 5 using magnetron sputtering;

[0050] Step 6: Prepare a photomask and use a wet etching method to create a groove in the insulating layer 5 on the low-resistivity zinc oxide region 4 to expose part of the ZnO;

[0051] Step 7: Prepare a photoresist mask, and fabricate a 1μm thick aluminum electrode 6 by electron beam evaporation and mask stripping.

[0052] Step 8: Prepare a photoresist mask, and prepare an aluminum electrode with a thickness of 1 μm by electron beam evaporation and mask stripping.

Claims

1. A zinc oxide / magnesium zinc oxygen structure alpha particle detector, characterized in that, The structure of the zinc oxide / magnesium zinc oxygen structure-based neutron detector is as follows: The surface of the alumina single crystal (1) is composed of a high-resistivity magnesium zinc oxide region (2) and a hole-conducting oxide layer region (3) from bottom to top. On both sides of the stepped structure are low-resistivity zinc oxide regions (4), and the upper surface of the low-resistivity zinc oxide region (4) is flush with the upper surface of the hole-conducting oxide layer region (3). On the upper surface of the hole-conducting oxide layer region (3) and the low-resistivity zinc oxide region (4) is an insulating layer (5), and a hole is opened in the insulating layer (5). The opening is a collecting electrode (6), and the collecting electrode (6) is in contact with the low-resistivity zinc oxide region (4). A gate electrode (7) is located directly above the hole-conducting oxide layer region (3) on the insulating layer (5), and the size of the gate electrode (7) is smaller than that of the hole-conducting oxide layer region (3).

2. The zinc oxide / magnesium zinc oxygen structure alpha particle detector according to claim 1, characterized in that, The thickness of the alumina single crystal (1) is 360 μm; The thickness of the high-resistivity magnesium-zinc-oxygen region (2) is 10μm-100μm, and the resistivity is 10. 6 -10 12 Ω·cm; The thickness of the hole-conducting oxide layer region (3) is 0.01 μm-5 μm, and its hole concentration is 1 × 10⁻⁶. 17 cm -3 -5×10 18 cm -3 ; The thickness of the low-resistivity zinc oxide region (4) is 10μm-100μm, and the resistivity is 10. -1 -10 5 Ω·cm; The thickness of the insulating layer (5) is 0.01μm-10μm; The thickness of the collecting electrode (6) is 0.01 μm-3 μm; The thickness of the gate electrode (7) is 0.01μm-3μm.

3. The zinc oxide / magnesium zinc oxygen structure alpha particle detector according to claim 1, characterized in that, The thickness ratio of the high-resistivity magnesium zinc oxide region (2) to the hole-conducting oxide layer region (3) is between 1000:1 and 10:

1.

4. The zinc oxide / magnesium zinc oxygen structure alpha particle detector according to claim 1, characterized in that, The ratio of magnesium atoms to zinc atoms in MgZnO is between 1000:1 and 1:

100.

5. A method for fabricating a zinc oxide / magnesium zinc oxygen structure alpha particle detector, characterized in that, The steps are as follows: Step 1: A high-resistivity magnesium zinc oxide region (2) and a hole-conducting oxide layer region (3) are epitaxially grown sequentially on an alumina single crystal (1); Step 2: After preparing the photoresist mask, the ladder structure is fabricated using dry etching or wet etching. Step 3: After cleaning, prepare low-resistivity zinc oxide regions by physical deposition or chemical vapor deposition (4); Step 4: Smooth the surface using chemical mechanical polishing or dry etching methods; Step 5: Prepare the insulating layer using physical deposition (5); Step 6: Prepare a photoresist mask and use dry etching or wet etching to create grooves in the insulating layer (5) on the low-resistivity zinc oxide region (4) to expose part of the ZnO; Step 7: Prepare a photoresist mask, and prepare the collecting electrode by physical deposition and mask stripping (6); Step 8: Prepare a photoresist mask, and fabricate the gate electrode by physical deposition and mask stripping (7).

Images