Beta-Ga2O3-based solar blind alpha particle detector and preparation method and application thereof

Abstract

The invention discloses a beta-Ga2O3-based solar blind alpha particle detector and a preparation method and application thereof, and relates to the technical field of detection.The detector comprises a Schottky contact electrode, an unintentionally doped epitaxial layer, an N-type heavily doped substrate and an ohmic contact electrode which are sequentially arranged from top to bottom, and the unintentionally doped epitaxial layer is a beta-Ga2O3 epitaxial layer; and the N type heavily doped substrate is N type beta-Ga2O3 doped with Sn. The substrate of the beta-Ga2O3-based Schottky structure solar blind alpha particle detector is heavily doped in a Sn doping mode, ohmic contact is more favorably formed, and the energy resolution capability is improved; the N-type homoepitaxy forbidden band width is large, the absorption cut-off wavelength is located in the solar-blind wave band, the method is not affected by sun illumination, and the method can be used in the more complex nuclear radiation detection field and achieve on-site detection of alpha particles.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, in particular to a β-Ga 2 O 3 Solar-blind alpha particle detector and its preparation method and application. Background Art

[0002] Alpha particles are composed of two protons and two neutrons. Alpha sources decay and emit alpha particles. There are many devices and methods in the related prior art that can identify the energy of alpha particles. Among them, semiconductor detectors identify alpha particles by monitoring the induced charge generated by the interaction between alpha particles and target atoms of semiconductor materials.

[0003] When used in deep space exploration and high-energy particle detection, the detector must work in a more complex detection environment, so higher requirements are placed on the detector's ability to withstand high temperatures and high pressures. However, the existing particle detectors are mostly made using traditional third-generation semiconductor materials such as silicon carbide and gallium nitride, which have a small bandgap and can absorb light in the solar band. Additional filters are required to get rid of the influence of sunlight, which seriously limits the development of detectors in complex environments and on-site particle detection. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a β-Ga 2 O 3 The solar-blind alpha particle detector and its preparation method and application are aimed at the application environment of extreme and on-site measurement, avoiding the shortcomings of the material itself, and proposing a β-Ga 2 O 3 The solar-blind alpha particle detector is designed to solve the problem that particle detectors made of traditional semiconductor materials are not suitable for use in complex environments with high temperature and high pressure, and require additional filters for on-site particle detection.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] One of the purposes of the present invention is to provide a β-Ga 2 O 3 Solar-blind alpha particle detector.

[0007] The β-Ga 2 O 3 A solar-blind alpha particle detector, the detector comprising a Schottky contact electrode, an unintentionally doped epitaxial layer, an N-type heavily doped substrate and an ohmic contact electrode arranged in sequence from top to bottom, wherein:

[0008] The unintentionally doped epitaxial layer is β-Ga 2 O 3Epitaxial layer; N-type homoepitaxial has a wide bandgap, and the absorption cutoff wavelength is located in the solar-blind band, which is not affected by sunlight. It can be used in more complex nuclear radiation detection fields and realize on-site detection of alpha particles.

[0009] The N-type heavily doped substrate is an N-type β-Ga doped with Sn. 2 O 3 ; The N-type heavily doped substrate is heavily doped by doping with Sn, which is more conducive to forming an ohmic contact and improving the energy resolution capability.

[0010] Due to β-Ga 2 O 3 The material has the advantages of ultra-wide bandgap, strong breakdown field, stable physical and chemical properties, absorption cutoff wavelength in the solar-blind band, and is not affected by sunlight. In terms of particle identification and energy measurement, compared with conventionally used silicon carbide detectors, it can be used in more complex irradiation environments under high temperature and high pressure.

[0011] In a preferred embodiment of the present invention:

[0012] The unintentionally doped epitaxial layer is a β-Ga with a 001 crystal orientation grown on an N-type heavily doped substrate by HVPE. 2 O 3 epitaxial layer; and / or,

[0013] The thickness of the unintentionally doped epitaxial layer is 20 μm-50 μm.

[0014] In a preferred embodiment of the present invention:

[0015] The Sn doping concentration is 1×10 18 cm -3 -6×10 19 cm -3 .

[0016] In a preferred embodiment of the present invention:

[0017] The Schottky contact electrode is deposited on the unintentionally doped epitaxial layer; and / or,

[0018] The Schottky contact electrode is a Ni / Au alloy or a Cr / Au alloy. Preferably, the thickness of the Cr or Ni metal is 10nm-50nm, and / or the thickness of the Au metal is 50nm-200nm.

[0019] In a preferred embodiment of the present invention:

[0020] The ohmic contact electrode is deposited at the bottom of the N-type heavily doped substrate; and / or,

[0021] The ohmic contact electrode is a Ti / Au alloy. Preferably, the thickness of the Ti metal is 20nm-50nm, and / or the thickness of the Au metal is 50nm-200nm.

[0022] The second object of the present invention is to provide a β-Ga 2 O 3 Preparation method of solar-blind alpha particle detector.

[0023] The β-Ga 2 O 3 A method for preparing a solar-blind alpha particle detector, the method comprising:

[0024] (1) Clean the Sn-doped N-type β-Ga 2 O 3 After a metal layer is deposited on the bottom, the ohmic contact electrode is formed after annealing;

[0025] (2) Using HVPE method to grow 001 crystal orientation β-Ga on N-type heavily doped substrate 2 O 3 an epitaxial layer, namely the unintentionally doped epitaxial layer;

[0026] (3) Depositing a metal layer on the unintentionally doped epitaxial layer to obtain the Schottky contact electrode.

[0027] In a preferred embodiment of the present invention:

[0028] In step (1):

[0029] The cleaning is carried out by ultrasonic cleaning with a solvent; and / or,

[0030] The metal layer is a Ti / Au alloy. Preferably, the metal layer is deposited by electron beam evaporation or magnetron sputtering. More preferably, Ti metal is deposited first and then Au metal is deposited; and / or,

[0031] The annealing treatment is protective Ar or N 2 Anneal at 450℃-600℃ for 1-5 minutes in a gas atmosphere.

[0032] In a preferred embodiment of the present invention:

[0033] In step (2):

[0034] The HVPE method comprises the following steps: 3 With O 2 The β-Ga 2 O 3 Epitaxial layer, preferably, the GaCl 3The flow rate is 10 sccm to 100 sccm, and / or, O 2 The flow rate is 5 sccm to 50 sccm, and / or the reaction temperature is 800° C. to 1000° C., the reaction time is 0.5 to 5 hours, and the reaction pressure is 0.01 atm to 1 atm.

[0035] In a preferred embodiment of the present invention:

[0036] In step (3):

[0037] The metal layer is a Ni / Au alloy. Preferably, the metal layer is deposited by electron beam evaporation or magnetron sputtering. More preferably, Ni metal is deposited first and then Au metal is deposited.

[0038] The third object of the present invention is to provide a β-Ga 2 O 3 The solar-blind alpha particle detector or the β-Ga prepared by the method according to the second object of the present invention 2 O 3 Application of solar-blind alpha particle detectors in on-site detection of nuclear radiation particles.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] 1. The present invention utilizes the high temperature and high pressure resistance characteristics of gallium oxide materials to ensure that the detector can still work normally under the conditions of high-energy particle radiation and deep space exploration, which is very beneficial to the detection of nuclear radiation;

[0041] 2. The present invention utilizes the characteristics of gallium oxide having a large bandgap and an absorption cutoff wavelength located in the solar-blind band, and can realize on-site measurement of α particles without the need for additional filters. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a structural schematic diagram of the detector of the present invention;

[0043] Among them, 1-Schottky contact electrode, 2-unintentionally doped epitaxial layer, 3-N-type heavily doped substrate, 4-Ohmic contact electrode;

[0044] Figure 2 This is a schematic diagram of the structure of a detector according to Embodiment 1 of the present invention;

[0045] Among them, 5-Ni metal, 6-Au metal, 7-β-Ga 2 O 3 Epitaxial layer, 8-N-type β-Ga 2 O 3 , 9-Ti metal, 10-Au metal;

[0046] Figure 3 This is a flow chart of manufacturing the detector according to Example 1 of the present invention;

[0047] Figure 4 This is a detection schematic diagram after the detector of Example 1 of the present invention is bonded to a PCB board. DETAILED DESCRIPTION

[0048] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0049] Example 1

[0050] like Figure 2 As shown, a β-Ga 2 O 3 The solar-blind alpha particle detector comprises a Schottky contact electrode, an unintentionally doped epitaxial layer, an N-type heavily doped substrate and an ohmic contact electrode arranged in sequence from top to bottom; wherein: the Schottky contact electrode is a Ni / Au alloy, with a size of 3mm×3mm and a square shape, the thickness of the Ni metal 5 is 10nm, and the thickness of the Au metal 6 is 50nm; the unintentionally doped epitaxial layer is a β-Ga with a 001 crystal orientation grown by the HVPE method 2 O 3 Epitaxial layer 7, thickness is 20 μm; N-type heavily doped substrate is Sn doping concentration is 1.0×10 18 cm -3 N-type β-Ga 2 O 3 8, the size is 10mm×10mm; the ohmic contact electrode is Ti / Au alloy, the thickness of Ti metal 9 is 20nm, and the thickness of Au metal 10 is 180nm.

[0051] like Figure 3 As shown, the above β-Ga 2 O 3 A method for making a solar-blind alpha particle detector comprises the following steps:

[0052] 1) Ultrasonic cleaning in acetone, ethanol and deionized water for 10 minutes each to remove Sn doping concentration of 1.0×10 18 cm -3 N-type β-Ga 2 O 3 8. Surface impurities to better form Schottky contact and ohmic contact;

[0053] 2) After the treatment in step 1) 2 O3 Ti / Au alloy with a thickness of 20nm / 180nm was deposited on the bottom by electron beam evaporation;

[0054] 3) The β-Ga treated in step 2) 2 O 3 Annealing was performed in a nitrogen atmosphere at 450° C. for 1 minute to form an ohmic contact electrode;

[0055] 4) Through HVPE method: GaCl 3 With O 2 The gas is introduced into the reaction chamber at a set flow rate to grow β-Ga with 001 crystal orientation. 2 O 3 Epitaxial layer, in which GaCl 3 The flow rate is 20 sccm, O 2 The flow rate is 10 sccm, the reaction temperature is 900°C, the reaction time is 2 hours, and the reaction pressure is 0.2 atm;

[0056] 5) Through electron beam evaporation, in β-Ga 2 O 3 A Ni / Au alloy with a thickness of 10 nm / 50 nm is deposited on the epitaxial layer 7 to form a Schottky contact electrode;

[0057] 6) The detector prepared in step 5) is connected to the PCB board via aluminum wire encapsulation bonding.

[0058] like Figure 4 As shown in the figure, after the α particle is vertically incident on the detector, it will pass through the epitaxial layer and the β-Ga 2 O 3 Electron-hole pairs are generated by the interaction and collected at both ends of the detector under the action of an external electric field. The signal is initially amplified by a charge-sensitive preamplifier, and the pulse-forming main amplifier further amplifies the signal, and finally forms an energy spectrum through a multi-channel pulse analyzer.

[0059] The present invention utilizes N-type β-Ga 2 O 3 The unique advantages of semiconductor materials include a larger bandgap, a higher breakdown field strength, and β-Ga grown by HVPE method. 2 O 3 Homoepitaxial wafers are heavily doped with Sn to increase the carrier concentration and promote the formation of ohmic contacts, thereby preparing Schottky structure particle detectors, which increases the possibility of high-energy particle detection, deep space detection and on-site detection of alpha particles.

[0060] Example 2

[0061] A β-Ga 2 O 3The solar-blind alpha particle detector comprises a Schottky contact electrode, an unintentionally doped epitaxial layer, an N-type heavily doped substrate and an ohmic contact electrode arranged in sequence from top to bottom; wherein: the Schottky contact electrode is a Cr / Au alloy, with a size of 3mm×3mm and a square shape, a thickness of Cr metal of 40nm, and a thickness of Au metal of 180nm; the unintentionally doped epitaxial layer is a β-Ga with a 001 crystal orientation grown by the HVPE method 2 O 3 The epitaxial layer has a thickness of 50 μm; the N-type heavily doped substrate has a Sn doping concentration of 5.0×10 19 cm -3 N-type β-Ga 2 O 3 , with a size of 10mm×10mm; the ohmic contact electrode is Ti / Au alloy, the thickness of Ti metal is 50nm, and the thickness of Au metal is 80nm.

[0062] The above β-Ga 2 O 3 A method for making a solar-blind alpha particle detector comprises the following steps:

[0063] 1) Ultrasonic cleaning in acetone, ethanol and deionized water for 10 minutes each to remove Sn doping concentration of 5.0×10 19 cm -3 N-type β-Ga 2 O 3 Surface impurities to better form Schottky contacts and ohmic contacts;

[0064] 2) After the treatment in step 1) 2 O 3 Ti / Au alloy with a thickness of 50nm / 80nm was deposited on the bottom by electron beam evaporation;

[0065] 3) The β-Ga treated in step 2) 2 O 3 Annealing was performed in a nitrogen atmosphere at 550° C. for 3 minutes to form an ohmic contact electrode;

[0066] 4) Through HVPE method: GaCl 3 With O 2 Gas reaction in β-Ga 2 O 3 β-Ga with 001 crystal orientation is grown on the surface 2 O 3 Epitaxial layer, in which GaCl 3 The flow rate is 80 sccm, O 2 The flow rate is 40 sccm, the reaction temperature is 950°C, the reaction time is 4 hours, and the reaction pressure is 0.8 atm;

[0067] 5) Through electron beam evaporation, in β-Ga 2 O 3 A Cr / Au alloy with a thickness of 40nm / 180nm is deposited on the epitaxial layer to form a Schottky contact electrode;

[0068] 6) The detector prepared in step 5) is connected to the PCB board via aluminum wire encapsulation bonding.

[0069] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A β-Ga2O3-based solar-blind α-particle detector, characterized in that The detector comprises a Schottky contact electrode, an unintentionally doped epitaxial layer, an N-type heavily doped substrate and an ohmic contact electrode arranged in sequence from top to bottom, wherein: The unintentionally doped epitaxial layer is a β-Ga2O3 epitaxial layer; The N-type heavily doped substrate is Sn-doped N-type β-Ga2O3.

2. The detector according to claim 1, characterized in that: The unintentionally doped epitaxial layer is a β-Ga2O3 epitaxial layer with a 001 crystal orientation grown on an N-type heavily doped substrate by HVPE method; and / or, The thickness of the unintentionally doped epitaxial layer is 20 μm-50 μm.

3. The detector according to claim 1, characterized in that: The Sn doping concentration is 1×10 18 cm -3 -6×10 19 cm -3 .

4. The detector according to claim 1, characterized in that: The Schottky contact electrode is deposited on the unintentionally doped epitaxial layer; and / or, The Schottky contact electrode is a Ni / Au alloy or a Cr / Au alloy. Preferably, the thickness of the Cr or Ni metal is 10nm-50nm, and / or the thickness of the Au metal is 50nm-200nm.

5. The detector according to claim 1, characterized in that: The ohmic contact electrode is deposited at the bottom of the N-type heavily doped substrate; and / or, The ohmic contact electrode is a Ti / Au alloy. Preferably, the thickness of the Ti metal is 20nm-50nm, and / or the thickness of the Au metal is 50nm-200nm.

6. A method for preparing a β-Ga2O3-based solar-blind α-particle detector as claimed in any one of claims 1 to 5, characterized in that The method include: (1) depositing a metal layer on the bottom of the cleaned Sn-doped N-type β-Ga2O3 and annealing the layer to form the ohmic contact electrode; (2) growing a β-Ga2O3 epitaxial layer with a 001 crystal orientation on an N-type heavily doped substrate using a HVPE method, i.e., the non-intentionally doped epitaxial layer; (3) Depositing a metal layer on the unintentionally doped epitaxial layer to obtain the Schottky contact electrode.

7. The method according to claim 6, characterized in that: In step (1): The cleaning is carried out by ultrasonic cleaning with a solvent; and / or, The metal layer is a Ti / Au alloy. Preferably, the metal layer is deposited by electron beam evaporation or magnetron sputtering. More preferably, Ti metal is deposited first and then Au metal is deposited; and / or, The annealing treatment is annealing at 450° C.-600° C. for 1-5 minutes in a protective Ar or N 2 gas atmosphere.

8. The method according to claim 6, characterized in that: In step (2): The HVPE method includes reacting GaCl3 with O2 gas to grow the β-Ga2O3 epitaxial layer. Preferably, the GaCl3 flow rate is 10sccm~100sccm, and / or the O2 flow rate is 5sccm~50sccm, and / or the reaction temperature is 800℃~1000℃, the reaction time is 0.5~5 hours, and the reaction pressure is 0.01atm~1atm.

9. The method according to claim 6, characterized in that: In step (3): The metal layer is a Ni / Au alloy. Preferably, the metal layer is deposited by electron beam evaporation or magnetron sputtering. More preferably, Ni metal is deposited first and then Au metal is deposited.

10. Use of the β-Ga2O3-based solar-blind α-particle detector as claimed in any one of claims 1 to 5 or the β-Ga2O3-based solar-blind α-particle detector prepared by the method as claimed in any one of claims 6 to 9 in the field of on-site detection of nuclear radiation particles.

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