Ultraviolet dual-band photoelectric detector based on integrated wide bandgap semiconductor junction and preparation method thereof

Abstract

The invention relates to an integrated wide bandgap semiconductor junction-based ultraviolet dual-band photoelectric detector and a preparation method thereof. An intrinsic semiconductor layer, a p-type semiconductor layer, a barrier layer, an intrinsic Ga2O3 layer and an n-type Ga2O3 layer are partially etched to form a first step; the intrinsic semiconductor layer, the p-type semiconductor layer and the barrier layer which are adjacent to the first step are etched to form a second step, the barrier layer, the intrinsic Ga2O3 layer and the n-type Ga2O3 layer which are adjacent to the second step form a third step, and the n-type semiconductor material layer at the top of the first step is in ohmic contact with the first metal electrode. The p-type wide-band-gap semiconductor layer at the top of the second step is in ohmic contact with the second metal electrode, and the n-type Ga2O3 layer at the top of the third step is in ohmic contact with the third metal electrode. According to the invention, external bias voltage is applied between two different electrodes selected from the three electrodes, and detection of light of three different ultraviolet bands can be realized through permutation and combination.

Description

Technical Field

[0001] The invention relates to the technical field of ultraviolet light detection devices, and in particular to an ultraviolet dual-band photoelectric detector based on an integrated wide-bandgap semiconductor junction and a preparation method thereof. Background Art

[0002] Ultraviolet light detection is another emerging research field after infrared and visible light detection. Compared with visible and infrared, ultraviolet detection has low background noise and high sensitivity, and can be widely used in environmental monitoring, flame monitoring, ozone hole monitoring and other fields.

[0003] Among the many photoelectric detection device structures, the same structure can often only achieve detection in a certain band. However, different bands of ultraviolet light have their own application fields. In order to achieve light detection in different bands, different devices often need to be combined together, which increases the complexity of photoelectric detectors and makes it difficult to meet people's demand for miniaturization and integration of devices. Summary of the invention

[0004] The present invention designs an ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction and a preparation method thereof, which solves the technical problem that in the photoelectric detection device structure in the prior art, the same structure can often only realize detection of a certain band and cannot meet the various needs of users.

[0005] In order to solve the above-mentioned technical problems, the present invention adopts the following solutions: An ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction is characterized in that: the semiconductor junction structure includes: a substrate, a buffer layer, an n-type semiconductor layer, an intrinsic semiconductor layer, a p-type semiconductor layer, a barrier layer, an intrinsic Ga2O3 layer and an n-type Ga2O3 layer; a portion of the intrinsic semiconductor layer, the p-type semiconductor layer, the barrier layer, the intrinsic Ga2O3 layer and the n-type Ga2O3 layer is etched away to form a first step, the intrinsic semiconductor layer, the p-type semiconductor layer and the barrier layer adjacent to the first step are etched away to form a second step, the barrier layer, the intrinsic Ga2O3 layer and the n-type Ga2O3 layer adjacent to the second step constitute a third step, the n-type semiconductor material layer at the top of the first step is in ohmic contact with the first metal electrode, the p-type wide bandgap semiconductor layer at the top of the second step is in ohmic contact with the second metal electrode, and the n-type Ga2O3 layer at the top of the third step is in ohmic contact with the third metal electrode.

[0006] Preferably, the substrate is made of sapphire, silicon, gallium nitride, silicon carbide or aluminum nitride.

[0007] Preferably, the buffer layer has a thickness of 0-2000nm. The n-type semiconductor layer is made of GaN or SiC; has a thickness of 0-3000nm; and has a carrier concentration of 10 17 -1019 cm -3 When the thickness of the buffer layer and the n-type semiconductor layer are both 0, the first metal electrode is directly connected to the substrate.

[0008] Preferably, the intrinsic semiconductor layer is GaN or SiC; the thickness is 100-3000nm; the carrier concentration is 10 17 -10 19 cm -3 .

[0009] Preferably, the p-type semiconductor layer is made of GaN or SiC; has a thickness of 50-1000 nm; and a carrier concentration of 10 16 -10 18 cm -3 .

[0010] Preferably, the barrier layer is AlN, MgO, AlGaO, MgZnO or SiO2, and has a thickness of 0-300 nm.

[0011] A method for preparing an ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction comprises the following steps: Step 1, growing a buffer layer on a substrate; Step 2, growing an n-type semiconductor layer on the buffer layer in step 1; Step 3, growing an intrinsic semiconductor layer on the n-type semiconductor layer in step 2; Step 4, growing a p-type semiconductor layer on the intrinsic semiconductor layer in step 3; Step 5, growing a barrier layer on the p-type semiconductor layer in step 4; Step 6, growing an intrinsic Ga2O3 layer on the barrier layer in step 5; Step 7, growing an n-type Ga2O3 layer on the intrinsic Ga2O3 layer of step 6 to form a multilayer structure; Step 8, etching a portion of the area above the n-type semiconductor layer and the p-type semiconductor layer in the multilayer structure in step 7 to expose the n-type semiconductor layer and the p-type semiconductor layer below the etched area; Step 9: Prepare different metal electrodes on the exposed n-type semiconductor layer and p-type semiconductor layer in step 8 and on the upper part of the n-type Ga2O3 layer that has not been etched, respectively. The metal electrodes are in ohmic contact with the material layer therebelow.

[0012] An application of an ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction in detecting short-wave ultraviolet light is characterized in that the positive and negative electrodes of the power supply are connected between a third metal electrode and a second metal electrode.

[0013] An application of an ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction in detecting long-wave ultraviolet light is characterized in that the positive and negative electrodes of the power supply are connected between a first metal electrode and a second metal electrode.

[0014] An application of an ultraviolet dual-band photodetector based on an integrated wide-bandgap semiconductor junction in wide-spectrum ultraviolet light, characterized in that the positive and negative electrodes of the power supply are connected between a third metal electrode and a first metal electrode.

[0015] The ultraviolet dual-band photodetector based on integrated wide bandgap semiconductor junction and its preparation method have the following beneficial effects: The present invention integrates homojunctions and heterojunctions formed by different semiconductor materials into the same device structure. External bias is applied between two different electrodes selected from three electrodes, and the detection of three different ultraviolet bands of light can be achieved through arrangement and combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the device provided in Example 1 of the present invention.

[0017] Figure 2 This is a schematic diagram of the wiring of the device provided in Example 1 of the present invention for short-wave ultraviolet detection.

[0018] Figure 3 This is a wiring diagram of the device provided in Example 1 of the present invention for detecting long-wave ultraviolet light.

[0019] Figure 4 This is a schematic diagram of the wiring of the device provided in Example 1 of the present invention for detecting wide-spectrum ultraviolet light.

[0020] Description of reference numerals: 1—substrate, 2—buffer layer, 3—n-type semiconductor layer, 4—intrinsic semiconductor layer, 5—p-type semiconductor layer, 6—barrier layer, 7—intrinsic Ga2O3 layer, 8—n-type Ga2O3 layer, 9—first metal electrode, 10—second metal electrode, 11—third metal electrode. DETAILED DESCRIPTION

[0021] Combine the following Figures 1 to 4 , the present invention is further described: Embodiment 1: See also Figure 1 , Figure 1A schematic diagram of the structure of an ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction provided in an embodiment of the present invention includes: a substrate 1, a buffer layer 2, an n-type semiconductor layer 3, an intrinsic semiconductor layer 4, a p-type semiconductor layer 5, a barrier layer 6, an intrinsic Ga2O3 layer 7, an n-type Ga2O3 layer 8, a first metal electrode 9, a second metal electrode 0, and a third metal electrode 11. The substrate 1, the buffer layer 2, the n-type semiconductor layer 3, the intrinsic semiconductor layer 4, the p-type semiconductor layer 5, the barrier layer 6, the intrinsic Ga2O3 layer 7, and the n-type Ga2O3 layer 8 are arranged in sequence from bottom to top.

[0022] The substrate 1 is an α-Al2O3 substrate. The buffer layer 2 is an intrinsic AlN layer with a thickness of 40 nm.

[0023] The n-type semiconductor layer 3 is Si-doped n-type GaN, the crystal structure is hexagonal, and the surface crystal orientation is <002> , the electron concentration is 1×10 18 cm -3 The first metal electrode 9 on the n-type semiconductor layer 3 is a double-layer stacked structure, which is Ti and Au from bottom to top, with thicknesses of 30nm and 120nm respectively.

[0024] The intrinsic semiconductor layer 4 is intrinsic GaN and has a thickness of 300 nm.

[0025] The material of the p-type semiconductor layer 5 is Mg-doped p-type GaN with a hole concentration of 1×10 17 cm -3 The second metal electrode 10 on the P-type semiconductor layer 5 is a double-layer stacked structure, which is Ni and Au from bottom to top, with thicknesses of 30nm and 100nm respectively.

[0026] The barrier layer 6 is AlN and has a thickness of 50 nm.

[0027] The Ga2O3 crystal structure in the intrinsic Ga2O3 layer 7 is monoclinic, the surface crystal orientation is <-201>, and the thickness is 300nm The n-type Ga2O3 layer 8 is Si-doped Ga2O3 with a monoclinic crystal structure, a surface crystal orientation of <-201>, and an electron concentration of 1×10 18 cm -3 The third metal electrode 11 above the n-type Ga2O3 layer 8 is a double-layer stacked structure, which is Ti and Au from bottom to top, with thicknesses of 30nm and 100nm respectively.

[0028] The material of each layer of the semiconductor junction structure in the present invention is not fixed, and different materials and different carrier concentrations may be involved. For example, when a certain material, such as an n-type SiC single crystal substrate, is used as the substrate 1, the buffer layer 2 and the n-type semiconductor layer 3 may not be needed, and the thickness of the buffer layer 2 and the n-type semiconductor layer 3 may be set to 0. When the thickness of the buffer layer 2 and the n-type semiconductor layer 3 is 0, that is, when they do not exist, the first metal electrode 9 is directly connected to the substrate 1, such as an n-type SiC single crystal substrate. When an intrinsic non-conductive substrate is used, the buffer layer 2 and the n-type semiconductor layer 3 must exist.

[0029] Embodiment 2: The second embodiment provides a method for preparing an ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction, comprising the following steps: Step 1: growing a buffer layer 2 on a substrate 1, the specific method is as follows: An α-Al2O3 substrate with a diameter of 2 inches and single-sided polishing along the c-plane was ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water for 10 minutes in sequence, and blown dry with nitrogen to form a substrate 1; an AlN layer with a thickness of 40 nm was grown on the substrate 1 using a metal organic chemical vapor deposition method.

[0030] Step 2: epitaxially grow Si-doped GaN as the n-type semiconductor layer 3 on the AlN buffer layer 2 in step 1 by using a metal organic chemical vapor deposition method, with a thickness of 2 μm.

[0031] Step 3: epitaxially grow intrinsic GaN with a thickness of 300 nm as the intrinsic semiconductor layer 4 on the n-type semiconductor layer 3 of step 2 by using a metal organic chemical vapor deposition method.

[0032] Step 4: epitaxially grow Mg-doped GaN with a thickness of 200 nm as the p-type semiconductor layer 5 on the intrinsic semiconductor layer 4 of step 3 by using a metal organic chemical vapor deposition method.

[0033] Step 5: epitaxially grow AlGaO with a thickness of 30 nm as a barrier layer 6 on the p-type semiconductor layer 5 of step 4 by using a metal organic chemical vapor deposition method.

[0034] Step 6: epitaxially grow an intrinsic Ga2O3 layer 7 with a thickness of 300 nm on the barrier layer 6 in step 5 using a metal organic chemical vapor deposition method.

[0035] Step 7: epitaxially grow an n-type Ga2O3 layer 8 with a thickness of 100 nm on the intrinsic Ga2O3 layer 7 in step 6 using a metal organic chemical vapor deposition method.

[0036] Step 8, dissociate the 2-inch sample obtained in step 7 into 1 cm×1 cm squares; then use a plasma etching process to etch a portion of the n-type Ga2O3 layer 8 to expose the p-type semiconductor layer 5 below the etched portion, and then etch a portion of the exposed p-type semiconductor layer 5 to expose the n-type semiconductor layer 3 below.

[0037] Step 9: Prepare different metal electrodes on the unetched n-type Ga2O3 layer 8 and the exposed p-type semiconductor layer 5 and n-type semiconductor layer 3, respectively. The metal electrodes are in ohmic contact with the material layer. The specific method is as follows: A magnetron sputtering process is used to sputter metal Ti and Au in sequence on the area above the unetched n-type Ga2O3 layer 8, with thicknesses of 30nm and 100nm respectively, to form a third metal electrode 11 with a double-layer structure; a magnetron sputtering process is used to sputter metal Ni and Au in sequence on a partial area above the exposed p-type semiconductor layer 5, with thicknesses of 30nm and 100nm respectively, to form a second metal electrode 10 with a double-layer structure; a magnetron sputtering process is used to sputter metal Ti and Au in sequence on a partial area above the exposed n-type semiconductor layer 3, with thicknesses of 30nm and 100nm respectively, to form a first metal electrode 9 with a double-layer structure.

[0038] Figure 2 The schematic diagram of the wiring of the prepared heterojunction when detecting short-wave ultraviolet light is shown in FIG.

[0039] Figure 3 The schematic diagram of the wiring of the prepared heterojunction when detecting long-wave ultraviolet light is shown in FIG.

[0040] Figure 4 Schematic diagram of the wiring of the prepared heterojunction when subjected to broadband ultraviolet light. The positive and negative electrodes of the power supply are connected between the third metal electrode 11 and the first metal electrode 9.

[0041] Embodiment 3: The difference between the third embodiment and the first embodiment is that the substrate 1 is insulating SiC; the thickness of the buffer layer 2 is 0; the n-type semiconductor material 3 is n-type SiC, and the electron concentration is 1×10 19 cm -3 ; Intrinsic semiconductor material 4 is intrinsic SiC; p-type semiconductor material 5 is p-type SiC, with a hole concentration of 1×10 18 cm -3 ; The barrier layer 6 is AlN with a thickness of 50nm.

[0042] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. An ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction, characterized in that: The semiconductor junction structure comprises: a substrate (1), a buffer layer (2), an n-type semiconductor layer (3), an intrinsic semiconductor layer (4), a p-type semiconductor layer (5), a barrier layer (6), an intrinsic Ga2O3 layer (7) and an n-type Ga2O3 layer (8); A portion of the intrinsic semiconductor layer (4), the p-type semiconductor layer (5), the barrier layer (6), the intrinsic Ga2O3 layer (7) and the n-type Ga2O3 layer (8) is etched away to form a first step. The intrinsic semiconductor layer (4), the p-type semiconductor layer (5) and the barrier layer (6) adjacent to the first step are etched away to form a second step. The barrier layer (6), the intrinsic Ga2O3 layer (7) and the n-type Ga2O3 layer (8) adjacent to the second step form a third step, and the n-type semiconductor material layer (3) at the top of the first step is in ohmic contact with the first metal electrode (9). The p-type wide bandgap semiconductor layer (5) at the top of the second step is in ohmic contact with the second metal electrode (10), and the n-type Ga2O3 layer (8) at the top of the third step is in ohmic contact with the third metal electrode (11).

2. The ultraviolet dual-band photodetector based on integrated wide bandgap semiconductor junction according to claim 1, characterized in that: The material of the substrate (1) is sapphire, silicon, gallium nitride, silicon carbide or aluminum nitride.

3. The ultraviolet dual-band photodetector based on integrated wide bandgap semiconductor junction according to claim 1, characterized in that: The buffer layer (2) has a thickness of 0-2000 nm, the n-type semiconductor layer (3) is made of GaN or SiC; has a thickness of 0-3000 nm; and has a carrier concentration of 10 17 -10 19 cm -3 When the thicknesses of the buffer layer (2) and the n-type semiconductor layer (3) are both 0, the first metal electrode (9) is directly connected to the substrate (1).

4. The ultraviolet dual-band photodetector based on integrated wide bandgap semiconductor junction according to claim 1, characterized in that: The intrinsic semiconductor layer (4) is GaN or SiC; has a thickness of 100-3000 nm; and a carrier concentration of 10 17 -10 19 cm -3 .

5. The ultraviolet dual-band photodetector based on integrated wide bandgap semiconductor junction according to claim 1, characterized in that: The p-type semiconductor layer (5) is made of GaN or SiC; has a thickness of 50-1000 nm; and a carrier concentration of 10 16 -10 18 cm -3 .

6. The ultraviolet dual-band photodetector based on integrated wide bandgap semiconductor junction according to claim 1, characterized in that: The barrier layer (6) is AlN, MgO, AlGaO, MgZnO or SiO2, and has a thickness of 0-300 nm.

7. A method for preparing an ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction according to any one of claims 1 to 6, comprising the following steps: Step 1: growing a buffer layer (2) on a substrate (1); Step 2, growing an n-type semiconductor layer (3) on the buffer layer (2) in step 1; Step 3, growing an intrinsic semiconductor layer (4) on the n-type semiconductor layer (3) in step 2; Step 4, growing a p-type semiconductor layer (5) on the intrinsic semiconductor layer (4) in step 3; Step 5, growing a barrier layer (6) on the p-type semiconductor layer (5) of step 4; Step 6, growing an intrinsic Ga2O3 layer (7) on the barrier layer (6) in step 5; Step 7, growing an n-type Ga2O3 layer (8) on the intrinsic Ga2O3 layer (7) of step 6 to form a multilayer structure; Step 8, etching a portion of the area above the n-type semiconductor layer (3) and the p-type semiconductor layer (5) in the multilayer structure in step 7 to expose the n-type semiconductor layer (3) and the p-type semiconductor layer (5) below the etched area; Step 9, respectively preparing different metal electrodes on the exposed n-type semiconductor layer (3) and p-type semiconductor layer (5) in step 8 and the upper part of the unetched n-type Ga2O3 layer (8), and the metal electrodes are in ohmic contact with the material layer below them.

8. An application of the ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction according to any one of claims 1 to 6 in detecting short-wave ultraviolet light, characterized in that: The positive and negative electrodes of the power supply are connected between the third metal electrode (11) and the second metal electrode (10).

9. An application of the ultraviolet dual-band photodetector based on an integrated wide bandgap semiconductor junction according to any one of claims 1 to 6 in detecting long-wave ultraviolet light, characterized in that: The positive and negative electrodes of the power supply are connected between the first metal electrode (9) and the second metal electrode (10).

10. An application of the ultraviolet dual-band photodetector based on integrated wide bandgap semiconductor junction according to any one of claims 1 to 6 in wide-spectrum ultraviolet light, characterized in that: The positive and negative electrodes of the power supply are connected between the third metal electrode (11) and the first metal electrode (9).

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