Nickel oxide-doped buried alpha particle detector and preparation method thereof

Abstract

The invention belongs to the technical field of semiconductor device preparation, and relates to a doped nickel oxide buried alpha particle detector and a preparation method thereof. The doped nickel oxide buried type alpha particle detector comprises an aluminum oxide single crystal, a zinc-doped weak P-type nickel oxide buried region, a strong P-type nickel oxide buried region, a low-resistance zinc oxide region, an insulating layer, a collecting electrode and a gate electrode. According to the invention, the doped nickel oxide buried alpha particle detector structure is designed, a gain current channel is controlled, an effective and simple process manufacturing technology is provided, the preparation problem of the oxide alpha particle detector with the internal gain characteristic is solved, and the development of the novel doped nickel oxide buried structure alpha particle detector is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor device preparation, and relates to a doped nickel oxide buried type alpha particle detector and a preparation method. BACKGROUND

[0002] Alpha particles, beta particles and protons and other charged particles have wide applications in radiation environment detection, nuclear energy utilization, deep space exploration and high energy physics experimental research, and with the progress of technology, higher requirements are put forward for detection equipment in the above-mentioned fields. The current mainstream gas detector and scintillator detector have problems of large volume, high energy consumption and the like, while the silicon-based semiconductor detector, although excellent in sensitivity, faces defects of insufficient radiation resistance and unstable performance in high temperature environment. This technical bottleneck prompts researchers to turn the research direction to the development of new semiconductor material detectors. Wide band gap oxide semiconductors represented by zinc oxide, nickel oxide and gallium oxide become ideal candidate materials for breaking through the limitations of existing technologies due to their excellent intrinsic radiation resistance and excellent high temperature stability. However, in the development of alpha particle detectors, oxide semiconductors still face two key difficulties: firstly, the electrical parameters of the material are difficult to accurately control, and there are problems such as single conduction type and difficulty in regulating resistivity by doping, which limits the diversity and functionality of the developed devices; secondly, the electric signal generated by alpha particles in the semiconductor material is relatively weak, and the existing device structure is simple and lacks effective signal amplification mechanism, which ultimately leads to poor signal-to-noise ratio of the detector.

[0003] In the prior art, a hole conduction type (P-type) nickel oxide is prepared by using an acceptor doping method, and a PN and PIN junction type device structure with a vertical structure (i.e. two end electrodes) is formed based on the nickel oxide and other electron conduction type (N-type) materials. The doped nickel oxide is usually not used as a detection sensitive area. This method has a lattice mismatch problem of two materials, and the defects caused thereby reduce the response signal strength, and the prepared detector can only collect the electron holes generated by the signal source as the response signal, without an amplification mechanism.

[0004] Based on the above problems, the application develops a doped nickel oxide buried type alpha particle detector, wherein the doped nickel oxide area directly serves as a detection sensitive area and is divided into a high resistance area and a low resistance area, the resistivity of the nickel oxide detection sensitive area in the high resistance area is regulated by a donor doping method so as to apply a collection electric field, and the free holes in the low resistance area are used to deplete the local free electrons in the signal amplification layer above the low resistance area to form a local semi-insulating area; and the same surface electrodes are prepared on both sides of the semi-insulating area in the signal amplification layer, a voltage is applied, the transient reduction of the resistivity of the semi-insulating area is caused by the response signal, and the transient output of the equivalent amplified current signal is realized. As can be seen, the application directly uses the doped nickel oxide as the detection sensitive area to prepare, which is simpler, solves the lattice adaptation problem, realizes the signal amplification function, and has prominent technical innovation. SUMMARY

[0005] The application aims at the key problem of further significantly improving the performance of the above-mentioned limited oxide alpha particle detector, and proposes an alpha particle detector and a preparation method based on a doped nickel oxide buried structure to realize a controllable gain channel and further reduce the gain voltage.

[0006] The technical scheme of the application is as follows:

[0007] A doped nickel oxide buried type alpha particle detector, comprising an aluminum oxide single crystal 1 (thickness 360 μm), a zinc-doped weak P-type nickel oxide buried area 2 (the concentration of zinc doping is 1×10 15 cm -3 -1×10 18 cm -3 , the concentration of holes is 1×10 15 cm -3 -1×10 17 cm -3 , the thickness is 1 μm-30 μm), a strong P-type nickel oxide buried area 3 (the concentration of holes is 1×10 17 cm -3 -1×10 19 cm -3 , the thickness is 1 μm-5 μm), a low resistance zinc oxide area 4 (the thickness is 10 μm-100 μm, the resistivity is 10 -1 -10 5 Ω·cm), an insulating layer 5 (the thickness is 0.01 μm-10 μm), a collection electrode 6 (the thickness is 0.01 μm-3 μm) and a gate electrode 7 (the thickness is 0.01 μm-3 μm).

[0008] The surface of the alumina single crystal 1 has a ladder structure composed of a zinc-doped weak P-type nickel oxide buried region 2 and a strong P-type nickel oxide buried region 3 arranged from bottom to top; a low-resistance zinc oxide region 4 is covered on the surface of the alumina single crystal 1 and the strong P-type nickel oxide buried region 3; an insulating layer 5 is arranged on the surface of the low-resistance zinc oxide region 4, two holes are opened in the insulating layer 5 to form a collecting electrode 6, and the collecting electrode 6 is in contact with the low-resistance zinc oxide region 4; a gate electrode 7 is arranged on the insulating layer 5 directly above the strong P-type nickel oxide buried region 3, and the size of the gate electrode 7 is smaller than that of the strong P-type nickel oxide buried region 3.

[0009] The distance between the upper surface of the low-resistance zinc oxide region 4 on the strong P-type nickel oxide buried region 3 and the lower surface of the insulating layer 5 is 1-3 μm.

[0010] The angle between the waist of the ladder structure and the lower base is 30-60°.

[0011] A preparation method of a doped nickel oxide buried type alpha particle detector, comprising the following steps:

[0012] Step 1: epitaxially growing a zinc-doped weak P-type nickel oxide buried region 2 on an alumina single crystal 1;

[0013] Step 2: depositing a strong P-type nickel oxide buried region 3 on the zinc-doped weak P-type nickel oxide buried region 2 by using a physical or chemical method;

[0014] Step 3: using photoresist mask and dry etching or wet etching to make a ladder structure;

[0015] Step 4: after cleaning, preparing a low-resistance zinc oxide region 4 by using a physical deposition or chemical vapor deposition method;

[0016] Step 5: performing surface leveling by using a chemical mechanical polishing or dry etching method, and reserving a ZnO channel above the ladder structure;

[0017] Step 6: preparing an insulating layer 5 by using a physical deposition method;

[0018] Step 7: preparing a photoresist mask, and opening slots in the insulating layer 5 on the low-resistance zinc oxide region 4 by using a dry etching or wet etching method to expose part of the low-resistance zinc oxide region 4;

[0019] Step 8: preparing a collecting electrode 6 by using a photoresist mask, a physical deposition method and a mask stripping method;

[0020] Step 9: preparing a gate electrode 7 by using a photoresist mask, a physical deposition method and a mask stripping method.

[0021] The beneficial effects of the present application are as follows: the present application designs a doped nickel oxide buried alpha particle detector structure, directly uses the doped nickel oxide area as a detection sensitive area, and divides the doped nickel oxide area into a high-resistance area and a low-resistance area, adjusts the resistivity of the nickel oxide detection sensitive area in the high-resistance area through a donor doping method, and is conducive to the application of an electric field. At the same time, the free holes in the low-resistance area are used to deplete the local free electrons in the signal amplification layer above the low-resistance area, to form a local semi-insulating area, so that no signal is output when there is no signal source excitation. The same surface electrodes are prepared on both sides of the semi-insulating area in the signal amplification layer, a voltage is applied, the transient decrease of the resistivity of the semi-insulating area is caused through a response signal, and the transient output of the equivalent amplified current signal is realized. As can be seen, the present application proposes an effective and simple process manufacturing technology, solves the preparation difficulty of the oxide alpha particle detector with internal gain characteristics, and realizes the development of a new type of doped nickel oxide buried structure alpha particle detector. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structure schematic diagram of a doped nickel oxide buried alpha particle detector.

[0023] In the figure: 1, alumina single crystal; 2, zinc-doped weak P-type nickel oxide buried area; 3, strong P-type nickel oxide buried area; 4, low-resistance zinc oxide area; 5, insulating layer; 6, collection electrode; 7, gate electrode. DETAILED DESCRIPTION

[0024] The specific implementation manners of the present application are further described below in combination with the technical solutions and the drawings.

[0025] Example 1

[0026] A preparation method of a doped nickel oxide buried alpha particle detector, comprising the following process steps:

[0027] Step 1: a zinc-doped weak P-type nickel oxide buried area 2 with a thickness of 1 μm, a zinc doping concentration of 1×10 15 cm -3 , and a hole concentration of 1×10 15 cm -3 is epitaxially grown on an alumina single crystal with a thickness of 360 μm;

[0028] Step 2: a strong P-type nickel oxide buried area 3 with a thickness of 1 μm and a hole concentration of 1×10 17 cm -3 is prepared on the zinc-doped weak P-type nickel oxide buried area 2 by using a magnetron sputtering method;

[0029] Step 3: a photoresist mask is prepared, a dry etching is used to make a ladder structure, and the included angle between the waist and the lower bottom of the ladder structure is controlled to be 60°;

[0030] Step 4: After cleaning, chemical vapor deposition is used to prepare a low-resistance zinc oxide region 4, i.e., a ZnO layer, with a thickness of 10 μm and a resistivity of 1 Ω·cm;

[0031] Step 5: Chemical mechanical polishing is used to perform surface leveling, and the thickness of the ZnO layer above the stepped structure is retained at 1 μm, and the thickness of the low-resistance zinc oxide region 4 on both sides of the stepped structure is 22 μm;

[0032] Step 6: A 0.01 μm-thick silicon dioxide insulating layer 5 is prepared by using a magnetron sputtering method;

[0033] Step 7: A photoresist mask is prepared, and a wet etching method is used to groove the insulating layer 5 on the ZnO layer to expose part of the ZnO layer;

[0034] Step 8: A 0.01 μm-thick aluminum electrode 6 is prepared by using a photoresist mask, an electron beam evaporation method, and a mask stripping method;

[0035] Step 9: A 0.01 μm-thick aluminum electrode 7 is prepared by using a photoresist mask, an electron beam evaporation method, and a mask stripping method.

[0036] Example 2

[0037] A preparation method of a doped nickel oxide buried α-particle detector includes the following process steps:

[0038] Step 1: A zinc-doped weak P-type nickel oxide buried region 2 with a thickness of 30 μm, a zinc doping concentration of 1×10 18 cm -3 , and a hole concentration of 1×10 17 cm -3 is epitaxially grown on an aluminum oxide single crystal with a thickness of 360 μm;

[0039] Step 2: A strong P-type nickel oxide buried region 3 with a thickness of 5 μm and a hole concentration of 1×10 19 cm -3 is prepared on the zinc-doped weak P-type nickel oxide buried region 2 by using a magnetron sputtering method;

[0040] Step 3: A photoresist mask is prepared, and a dry etching method is used to make a stepped structure, and the included angle between the waist and the lower bottom of the stepped structure is controlled to be 50°;

[0041] Step 4: After cleaning, a chemical vapor deposition method is used to prepare a low-resistance zinc oxide region 4, i.e., a ZnO layer, with a thickness of 100 μm and a resistivity of 10 5 Ω·cm;

[0042] Step 5: A chemical mechanical polishing method is used to perform surface leveling, and the thickness of the ZnO layer above the stepped structure is retained at 3 μm, and the thickness of the low-resistance zinc oxide region 4 on both sides of the stepped structure is 22 μm;

[0043] Step 6: A 10 μm thick silicon dioxide insulating layer 5 is prepared by magnetron sputtering method;

[0044] Step 7: A photoresist mask is prepared, and a groove is etched in the insulating layer 5 on the ZnO layer by wet etching method, exposing part of the ZnO layer;

[0045] Step 8: A 3 μm thick aluminum electrode 6 is prepared by photoresist mask, electron beam evaporation and mask stripping method;

[0046] Step 9: A 3 μm thick aluminum electrode 7 is prepared by photoresist mask, electron beam evaporation and mask stripping method.

[0047] Example 3

[0048] A preparation method of a doped nickel oxide buried α particle detector, comprising the following process steps:

[0049] Step 1: A 18 μm, zinc-doped weak P-type nickel oxide buried region 2 with a zinc doping concentration of 1×10 16 cm -3 and a hole concentration of 1×10 16 cm -3 is epitaxially grown on an alumina single crystal with a thickness of 360 μm;

[0050] Step 2: A 2 μm thick, strong P-type nickel oxide buried region 3 with a hole concentration of 1×10 18 cm -3 is prepared on the region 2 by magnetron sputtering method;

[0051] Step 3: After a photoresist mask is prepared, a ladder structure is made by dry etching, and the included angle between the waist of the ladder structure and the lower bottom is controlled to be 30°;

[0052] Step 4: After cleaning, a 30 μm thick, low-resistance zinc oxide region 4 with a resistivity of 10 3 Ω·cm is prepared by chemical vapor deposition, which is the ZnO layer;

[0053] Step 5: Surface leveling is performed by chemical mechanical polishing method, the thickness of the ZnO layer above the ladder structure is reserved to be 2 μm, and the thickness of the zinc oxide in the low-resistance zinc oxide region 4 on both sides of the ladder structure is 22 μm;

[0054] Step 6: A 0.5 μm thick silicon dioxide insulating layer 5 is prepared by magnetron sputtering method;

[0055] Step 7: A photoresist mask is prepared, and a groove is etched in the insulating layer 5 on the ZnO layer by wet etching method, exposing part of the ZnO;

[0056] Step 8: A 2 μm thick aluminum electrode 6 is prepared using photolithographic masking, e-beam evaporation, and lift-off.

[0057] Step 9: A 2 μm thick aluminum electrode 7 is prepared using photolithographic masking, e-beam evaporation, and lift-off.

Claims

1. A doped nickel oxide buried alpha particle detector, characterized in that, The structure of the doped nickel oxide buried alpha particle detector is as follows: The alumina single crystal (1) has a ladder structure composed of a zinc-doped weak P-type nickel oxide buried region (2) and a strong P-type nickel oxide buried region (3) arranged from bottom to top on the surface of the alumina single crystal (1); a low-resistance zinc oxide region (4) is covered on the region without covering on the surface of the alumina single crystal (1) and the strong P-type nickel oxide buried region (3); an insulating layer (5) is arranged on the surface of the low-resistance zinc oxide region (4), two holes are opened on the insulating layer (5) to form a collecting electrode (6), and the collecting electrode (6) is in contact with the low-resistance zinc oxide region (4); a gate electrode (7) is arranged on the insulating layer (5) directly above the strong P-type nickel oxide buried region (3), and the size of the gate electrode (7) is smaller than that of the strong P-type nickel oxide buried region (3).

2. The doped nickel oxide buried alpha particle detector of claim 1, wherein, The thickness of the alumina single crystal (1) is 360 μm; The concentration of zinc doping in the zinc-doped weak P-type nickel oxide buried region (2) is 1 x 10 15 cm -3 -1 x 10 18 cm -3 , and the concentration of holes is 1 x 10 15 cm -3 -1 x 10 17 cm -3 , and the thickness is 1 μm-30 μm; The concentration of holes in the buried region (3) of strongly P-type nickel oxide is 1 x 1018cm-3 17 cm -3 -1 x 1018cm-3 19 cm -3 with a thickness of 1 μm - 5 μm; The thickness of the low resistance zinc oxide region (4) is 10 μm to 100 μm, and the resistivity is 10 -1 -10 5 Ω-cm; The thickness of the insulating layer (5) is 0.01 μm-10 μm; The thickness of the collecting electrode (6) is 0.01 μm-3 μm; The thickness of the gate electrode (7) is 0.01 μm-3 μm.

3. The doped nickel oxide buried alpha particle detector according to claim 1, wherein The distance between the upper surface of the low-resistance zinc oxide region (4) on the strong P-type nickel oxide buried region (3) and the lower surface of the insulating layer (5) is 1 μm-3 μm.

4. The doped nickel oxide buried alpha particle detector of claim 1, wherein, The angle between the waist of the ladder structure and the lower base is 30°-60°.

5. A method of producing the doped nickel oxide buried alpha particle detector of claim 1, characterized by, The steps are as follows: Step 1: epitaxially growing a zinc-doped weak P-type nickel oxide buried region (2) on the alumina single crystal (1); Step 2: depositing a strong P-type nickel oxide buried region (3) on the zinc-doped weak P-type nickel oxide buried region (2) by using a physical or chemical method; Step 3: after preparing a photoresist mask, a dry etching or wet etching method is used to make the ladder structure; Step 4: after cleaning, a low-resistance zinc oxide region (4) is prepared by using a physical deposition or chemical vapor deposition method; Step 5: a surface is flattened by using a chemical mechanical polishing or dry etching method, and a ZnO channel is reserved above the ladder structure; Step 6: an insulating layer (5) is prepared by using a physical deposition method; Step 7: after preparing a photoresist mask, a dry etching or wet etching method is used to groove the insulating layer (5) on the low-resistance zinc oxide region (4) to expose part of the low-resistance zinc oxide region (4); Step 8: a collecting electrode (6) is prepared by using a photoresist mask, a physical deposition method and a mask stripping method; Step 9: a gate electrode (7) is prepared by using a photoresist mask, a physical deposition method and a mask stripping method.

Images