A gallium oxide film and its preparation method and ultraviolet detection device

Abstract

The present invention relates to a gallium oxide film and a preparation method thereof and an ultraviolet detection device. The preparation method comprises: growing a gallium oxide buffer layer on a substrate; forming a gallium vacancy gallium oxide layer on a surface of the gallium oxide buffer layer away from the substrate; growing a gallium oxide layer on a surface of the gallium vacancy gallium oxide layer away from the substrate; obtaining the gallium oxide film; and in the process of forming the gallium vacancy gallium oxide layer, intermittently introducing an oxygen source and performing an annealing treatment. The preparation method of the present invention obtains a gallium vacancy gallium oxide layer rich in gallium vacancies by intermittently introducing an oxygen source, thereby reducing the dislocation density of the gallium oxide film. When applied to an ultraviolet detection device, the performance and reliability of the device are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor devices and relates to a gallium oxide material, in particular to a gallium oxide film and a preparation method thereof and an ultraviolet detection device. Background Art

[0002] When solar-blind ultraviolet light passes through the atmosphere, its photon target signal will react strongly with the ozone layer and be completely absorbed. Therefore, solar-blind ultraviolet light (band 200nm-280nm) is almost non-existent in the atmosphere. Based on the advantage of solar-blind ultraviolet light having almost zero background signal in the atmosphere, it has important application prospects in the fields of high-voltage transmission line detection, weather warning, fire warning, missile identification and tracking, and shipboard communications.

[0003] Gallium oxide has an ultra-wide bandgap width (4.8eV-4.9eV), high breakdown field strength (8mV / cm) and a high Baliga's Figure of Merit (BFOM). Compared with other wide-bandgap semiconductor materials, gallium oxide has a relatively suitable bandgap width, making it very suitable for solar-blind ultraviolet detection. Its absorption coefficient near the absorption edge can reach 10 5 cm -1 , is a natural material for day-blind UV detection and has good practical value.

[0004] At present, the main problems restricting the development of gallium oxide are the preparation of gallium oxide single crystal substrates, the crystal quality of gallium oxide epitaxy, and p-type doping. Improving the quality of gallium oxide films can be achieved by regulating impurities, dislocations, stacking faults or point defects during the epitaxial growth process. Dislocations and defects in gallium oxide films have a great impact on the performance and reliability of ultraviolet detection devices. How to obtain high-quality gallium oxide films is the focus of the industry.

[0005] Therefore, it is necessary to provide a gallium oxide film with low dislocation density, a preparation method thereof, and an ultraviolet detection device. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a gallium oxide film and a preparation method thereof and an ultraviolet detection device. The preparation method can reduce the dislocation density of the gallium oxide film, and when applied to an ultraviolet detection device, the performance and reliability of the device are improved.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a gallium oxide thin film, the preparation method comprising:

[0009] A gallium oxide buffer layer is grown on a substrate; a gallium vacancy gallium oxide layer is formed on a surface of the gallium oxide buffer layer away from the substrate; a gallium oxide layer is grown on a surface of the gallium vacancy gallium oxide layer away from the substrate; and the gallium oxide film is obtained.

[0010] During the process of forming the gallium vacancy gallium oxide layer, an oxygen source is intermittently introduced and annealing is performed.

[0011] The preparation method of the gallium oxide film provided by the present invention sets a gallium vacancy gallium oxide layer on the surface of the gallium oxide buffer layer, and the gallium vacancy gallium oxide layer can make the misfit dislocations generated by heteroepitaxial growth to undergo dislocation climb, form dislocation bending or annihilation, and greatly reduce the dislocation density from the bottom layer, thereby realizing the low dislocation density growth of the gallium oxide film. When the obtained gallium oxide film is applied to ultraviolet detection devices, the performance and reliability of the devices are improved.

[0012] Preferably, the intermittent introduction of the oxygen source comprises: introducing the oxygen source for 3s-10s, then stopping the introduction of the oxygen source for 2s-6s, and repeating the cycle until a gallium oxide epitaxial layer with a thickness of 10nm-500nm is obtained.

[0013] Preferably, the forming of the gallium vacancy gallium oxide layer comprises: obtaining a gallium oxide epitaxial layer under the condition of continuous introduction of a gallium source and intermittent introduction of an oxygen source, and forming the gallium vacancy gallium oxide layer through annealing.

[0014] Preferably, the annealing process is performed in a hydrogen atmosphere.

[0015] Preferably, the annealing temperature is above 600°C.

[0016] Preferably, the oxygen source has an inflow rate of 30 sccm-100 sccm.

[0017] Preferably, the inlet flow rate of the gallium source is 5 sccm-50 sccm.

[0018] Preferably, the Ga concentration in the gallium oxide epitaxial layer is 5‰-1%.

[0019] Preferably, the temperature for forming the gallium vacancy gallium oxide layer is 600°C-800°C.

[0020] Preferably, the absolute pressure for forming the gallium vacancy gallium oxide layer is 20 mbar-150 mbar.

[0021] Preferably, the growing of the gallium oxide buffer layer comprises: growing a gallium oxide buffer layer with a thickness of 20nm-100nm under the conditions of a temperature of 500°C-600°C, an absolute pressure of 20mbar-150mbar, a gallium source flow rate of 50sccm-500sccm and an oxygen flow rate of 30sccm-100sccm.

[0022] Preferably, the growing of the gallium oxide layer comprises: growing a gallium oxide layer with a thickness of 500nm-2500nm under the conditions of a temperature of 1000°C-1200°C, an absolute pressure of 50mbar-100mbar, a gallium source flow rate of 50sccm-500sccm and an oxygen flow rate of 50sccm-100sccm.

[0023] In a second aspect, the present invention provides a gallium oxide thin film, which is prepared by the preparation method described in the first aspect.

[0024] In a third aspect, the present invention provides an ultraviolet detection device, which includes the gallium oxide thin film prepared by the preparation method described in the first aspect, or includes the gallium oxide thin film described in the second aspect.

[0025] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The preparation method of the gallium oxide film provided by the present invention sets a gallium vacancy gallium oxide layer on the surface of the gallium oxide buffer layer, and the gallium vacancy gallium oxide layer can make the misfit dislocations generated by heteroepitaxial growth to undergo dislocation climb, form dislocation bending or annihilation, and greatly reduce the dislocation density from the bottom layer, thereby realizing the low dislocation density growth of the gallium oxide film. When the obtained gallium oxide film is applied to ultraviolet detection devices, the performance and reliability of the devices are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the structure of the gallium oxide film provided in Example 1 of the present invention.

[0029] Wherein: 1, sapphire substrate; 2, gallium oxide buffer layer; 3, gallium vacancy gallium oxide layer; 4, gallium oxide layer. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0031] A certain embodiment of the present invention provides a method for preparing a gallium oxide thin film, the preparation method comprising:

[0032] A gallium oxide buffer layer is grown on a substrate; a gallium vacancy gallium oxide layer is formed on a surface of the gallium oxide buffer layer away from the substrate; a gallium oxide layer is grown on a surface of the gallium vacancy gallium oxide layer away from the substrate; and the gallium oxide film is obtained.

[0033] During the process of forming the gallium vacancy gallium oxide layer, an oxygen source is intermittently introduced and annealing is performed.

[0034] The preparation method of the gallium oxide film provided by the present invention sets a gallium vacancy gallium oxide layer on the surface of the gallium oxide buffer layer, and the gallium vacancy gallium oxide layer can make the misfit dislocations generated by heteroepitaxial growth to undergo dislocation climb, form dislocation bending or annihilation, and greatly reduce the dislocation density from the bottom layer, thereby realizing the low dislocation density growth of the gallium oxide film. When the obtained gallium oxide film is applied to ultraviolet detection devices, the performance and reliability of the devices are improved.

[0035] Optionally, the substrate includes a sapphire substrate, a silicon substrate, a silicon carbide substrate or an Al 2 O 3 / Ga 2 O 3 The composite substrate is preferably a sapphire substrate.

[0036] Optionally, in the preparation method provided by the present invention, the oxygen source used includes but is not limited to oxygen (O 2 ), the gallium source used includes but is not limited to triethylgallium (TEGa) and / or trimethylgallium (TMGa), and the carrier gas used includes but is not limited to argon.

[0037] In some embodiments, the intermittent introduction of the oxygen source includes: introducing the oxygen source for 3s-10s, then stopping the introduction of the oxygen source for 2s-6s, and repeating the cycle until a gallium oxide epitaxial layer with a thickness of 10nm-500nm is obtained.

[0038] In one cycle of intermittently introducing the oxygen source, the time for introducing the oxygen source is 3s-10s, for example, 3s, 5s, 6s, 8s or 10s, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0039] In one cycle of intermittently introducing the oxygen source, the time for stopping introducing the oxygen source is 2s-6s, for example, it can be 2s, 3s, 4s, 5s or 6s, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0040] The thickness of the gallium oxide epitaxial layer obtained by intermittently introducing an oxygen source is 10 nm-500 nm, for example, 10 nm, 50 nm, 100 nm, 150 nm, 200 nm, 300 nm, 400 nm or 500 nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0041] In some embodiments, the forming of the gallium vacancy gallium oxide layer comprises: obtaining a gallium oxide epitaxial layer under the condition of continuous introduction of a gallium source and intermittent introduction of an oxygen source, and forming the gallium vacancy gallium oxide layer through annealing.

[0042] In some embodiments, the annealing process is performed in a hydrogen atmosphere.

[0043] When the oxygen source is stopped and the gallium source is continuously introduced, small-sized gallium particles will be formed on the surface. When the oxygen source is introduced, gallium oxide will continue to grow. This cycle will cause a large number of gallium particles to be present in the gallium oxide epitaxial layer. Annealing treatment is then performed in a hydrogen atmosphere to allow the gallium particles in the gallium oxide epitaxial layer to escape, forming a large number of gallium vacancies, thereby obtaining a gallium vacancy gallium oxide layer.

[0044] In some embodiments, the hydrogen flow rate during the annealing treatment is 80 slm-120 slm, for example, 80 slm, 90 slm, 100 slm, 110 slm or 120 slm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0045] In some embodiments, the temperature of the annealing treatment is above 600°C, for example, it can be 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, 1500°C, 1600°C or 1800°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also used, preferably 600°C-800°C.

[0046] In some embodiments, the annealing time is 10 min-30 min, for example, 10 min, 15 min, 20 min, 25 min or 30 min, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0047] When growing the gallium vacancy gallium oxide layer, the amount of gallium vacancies in the gallium vacancy gallium oxide layer can be controlled by controlling the flow rate of the oxygen source and the flow rate of the gallium source.

[0048] In some embodiments, the oxygen source has an inlet flow rate of 30 sccm-100 sccm, for example, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 80 sccm or 100 sccm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0049] In some embodiments, the inlet flow rate of the gallium source is 5sccm-50sccm, for example, it can be 5sccm, 10sccm, 20sccm, 30sccm, 40sccm or 50sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] In some embodiments, the Ga concentration in the gallium oxide epitaxial layer is 5‰-1%. The Ga concentration ratio in the present invention refers to the ratio of the number of atoms of the gallium element in the entire gallium oxide epitaxial layer. Under the conditions of controlling the oxygen source flow rate, the gallium source flow rate and the intermittent oxygen source flow time, the Ga concentration in the gallium oxide epitaxial layer can be 5‰-1%.

[0051] In some embodiments, the temperature for forming the gallium vacancy gallium oxide layer is 600°C-800°C, for example, 600°C, 650°C, 700°C, 750°C or 800°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0052] In some embodiments, the absolute pressure for forming the gallium vacancy gallium oxide layer is 20 mbar-150 mbar, for example, 20 mbar, 40 mbar, 50 mbar, 60 mbar, 80 mbar, 100 mbar, 120 mbar or 150 mbar, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] In some embodiments, growing the gallium oxide buffer layer includes growing a gallium oxide buffer layer with a thickness of 20nm-100nm under the conditions of a temperature of 500°C-600°C, an absolute pressure of 20mbar-150mbar, a gallium source flow rate of 50sccm-500sccm and an oxygen flow rate of 30sccm-100sccm.

[0054] The temperature for growing the gallium oxide buffer layer is 500° C.-600° C., for example, 500° C., 550° C. or 600° C., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0055] The absolute pressure for growing the gallium oxide buffer layer is 20 mbar-150 mbar, for example, 20 mbar, 50 mbar, 60 mbar, 80 mbar, 100 mbar, 120 mbar or 150 mbar, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0056] The gallium source flow rate for growing the gallium oxide buffer layer is 50 sccm-500 sccm, for example, 50 sccm, 100 sccm, 200 sccm, 300 sccm, 400 sccm or 500 sccm, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0057] The oxygen flow rate for growing the gallium oxide buffer layer is 30 sccm-100 sccm, for example, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 80 sccm or 100 sccm, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0058] The thickness of the grown gallium oxide buffer layer is 20 nm-100 nm, for example, 20 nm, 40 nm, 50 nm, 60 nm, 80 nm or 100 nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0059] In some embodiments, growing the gallium oxide layer includes growing a gallium oxide layer with a thickness of 500nm-2500nm under the conditions of a temperature of 1000°C-1200°C, an absolute pressure of 50mbar-100mbar, a gallium source flow rate of 50sccm-500sccm and an oxygen flow rate of 50sccm-100sccm.

[0060] The temperature for growing the gallium oxide layer is 1000° C.-1200° C., for example, 1000° C., 1050° C., 1100° C., 1150° C. or 1200° C., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0061] The absolute pressure for growing the gallium oxide layer is 50 mbar-100 mbar, for example, 50 mbar, 60 mbar, 80 mbar, 90 mbar or 100 mbar, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0062] The gallium source flow rate for growing the gallium oxide layer is 50 sccm-500 sccm, for example, 50 sccm, 100 sccm, 200 sccm, 300 sccm, 400 sccm or 500 sccm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0063] The oxygen flow rate for growing the gallium oxide layer is 50 sccm-100 sccm, for example, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm or 100 sccm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] The thickness of the grown gallium oxide layer is 500nm-2500nm, for example, 500nm, 600nm, 700nm, 800nm, 1000nm, 1500nm, 2000nm or 2500nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0065] A certain embodiment of the present invention provides a gallium oxide thin film, and the gallium oxide thin film is prepared by the preparation method described in any embodiment.

[0066] A certain embodiment of the present invention provides an ultraviolet detection device, which includes a gallium oxide thin film prepared by the preparation method described in any embodiment, or includes the gallium oxide thin film described in any embodiment.

[0067] Optionally, an electrode is deposited on the gallium oxide layer of the gallium oxide film to obtain the ultraviolet detection device.

[0068] Optionally, the material of the electrode includes titanium and / or gold.

[0069] Example 1

[0070] This embodiment provides a Figure 1 The method for preparing the gallium oxide film comprises the following steps:

[0071] (1) A gallium oxide buffer layer 2 is grown on one side of the sapphire substrate 1: a gallium oxide buffer layer 2 having a thickness of 60 nm is grown under the conditions of a temperature of 550° C., an absolute pressure of 80 mbar, a TEGa flow rate of 300 sccm, and an oxygen flow rate of 60 sccm.

[0072] (2) A gallium vacancy gallium oxide layer 3 is formed on the surface of the gallium oxide buffer layer 2 away from the sapphire substrate 1: Under the conditions of a temperature of 700°C and an absolute pressure of 80 mbar, TEGa is continuously introduced at a flow rate of 30 sccm, and oxygen is intermittently introduced at a flow rate of 60 sccm to obtain a gallium oxide epitaxial layer with a thickness of 150 nm and a Ga concentration of 5‰-1%; in one cycle of intermittent oxygen introduction, the oxygen introduction is first stopped for 4 s, and then oxygen is introduced for 6 s.

[0073] Hydrogen gas was introduced at a flow rate of 100 slm, and annealing treatment was performed in a hydrogen atmosphere to obtain the gallium vacancy gallium oxide layer 3; the annealing treatment temperature was 1200° C., and the time was 20 min.

[0074] (3) Growing a gallium oxide layer 4 on the surface of the gallium vacancy gallium oxide layer 3 away from the sapphire substrate 1: growing a gallium oxide layer 4 with a thickness of 2000 nm under the conditions of a temperature of 1100° C., an absolute pressure of 80 mbar, a TEGa flow rate of 250 sccm and an oxygen flow rate of 80 sccm.

[0075] Comparative Example 1

[0076] This comparative example provides a method for preparing a gallium oxide thin film, comprising the following steps:

[0077] (1) A gallium oxide buffer layer is grown on one side of the sapphire substrate: a gallium oxide buffer layer with a thickness of 60 nm is grown under the conditions of a temperature of 550°C, an absolute pressure of 80 mbar, a TEGa flow rate of 300 sccm, and an oxygen flow rate of 60 sccm.

[0078] (2) Growing a gallium oxide layer on the surface of the gallium oxide buffer layer away from the sapphire substrate: growing a gallium oxide layer with a thickness of 2000 nm under the conditions of a temperature of 1100°C, an absolute pressure of 80 mbar, a TEGa flow rate of 250 sccm and an oxygen flow rate of 80 sccm.

[0079] Performance Characterization

[0080] Electrodes were set on the surface of the gallium oxide layer of the gallium oxide film provided in the above embodiments and comparative examples to obtain an MSM (Metal-Semiconductor-Metal) day-blind ultraviolet light point detector. The transmittance, dark current and responsivity of the gallium oxide film were tested, and the results are shown in Table 1.

[0081] The transmittance is measured using an ultraviolet-visible spectrophotometer UV-VIS.

[0082] The dark current test method is: under 254nm ultraviolet light irradiation, the current and voltage of the detector are sampled to obtain an IV curve. The current with light source irradiation is called photocurrent, and the current collected without light source irradiation is dark current. The dark current in the present invention corresponds to the current at 5V voltage.

[0083] Responsivity R λ =I ph / P inc , where R λ is the responsivity of the detector under λnm wavelength light, I ph is the photocurrent of the detector under λnm wavelength light, Pinc is the incident light power; that is, the responsivity is the photocurrent generated per watt of incident radiation.

[0084] Table 1

[0085]

[0086] In summary, the preparation method of the gallium oxide film provided by the present invention sets a gallium vacancy gallium oxide layer on the surface of the gallium oxide buffer layer, and the gallium vacancy gallium oxide layer can make the misfit dislocations generated by heteroepitaxial growth to undergo dislocation climb, form dislocation bending or annihilation, and greatly reduce the dislocation density from the bottom layer, thereby achieving low dislocation density growth of the gallium oxide film. When the obtained gallium oxide film is applied to ultraviolet detection devices, the performance and reliability of the device are improved.

[0087] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a gallium oxide thin film, characterized in that: The preparation method comprises: Growing a gallium oxide buffer layer on a substrate; forming a gallium vacancy gallium oxide layer on a surface of the gallium oxide buffer layer away from the substrate; growing a gallium oxide layer on a surface of the gallium vacancy gallium oxide layer away from the substrate; obtaining the gallium oxide film; In the process of forming the gallium vacancy gallium oxide layer, an oxygen source is intermittently introduced and annealing is performed; The intermittent introduction of the oxygen source comprises: introducing the oxygen source for 3s-10s, then stopping the introduction of the oxygen source for 2s-6s, and repeating the cycle until a gallium oxide epitaxial layer with a thickness of 10nm-500nm is obtained; The forming of the gallium vacancy gallium oxide layer comprises: obtaining a gallium oxide epitaxial layer under the condition of continuous introduction of a gallium source and intermittent introduction of an oxygen source, and forming the gallium vacancy gallium oxide layer through annealing.

2. The preparation method according to claim 1, characterized in that: The annealing process is performed in a hydrogen atmosphere.

3. The preparation method according to claim 1, characterized in that: The annealing treatment is performed at a temperature of 600° C. or higher.

4. The preparation method according to claim 1, characterized in that: The oxygen source has an inflow rate of 30 sccm-100 sccm.

5. The preparation method according to claim 1, characterized in that: The inlet flow rate of the gallium source is 5 sccm-50 sccm.

6. The preparation method according to claim 1, characterized in that: The Ga concentration in the gallium oxide epitaxial layer is 5‰-1%.

7. The preparation method according to claim 1, characterized in that: The temperature for forming the gallium vacancy gallium oxide layer is 600°C-800°C.

8. The preparation method according to claim 1, characterized in that: The absolute pressure for forming the gallium vacancy gallium oxide layer is 20 mbar-150 mbar.

9. The preparation method according to claim 1, characterized in that: The growing of the gallium oxide buffer layer comprises: growing a gallium oxide buffer layer with a thickness of 20nm-100nm under the conditions of a temperature of 500°C-600°C, an absolute pressure of 20mbar-150mbar, a gallium source flow rate of 50sccm-500sccm and an oxygen flow rate of 30sccm-100sccm.

10. The preparation method according to claim 1, characterized in that: The growing of the gallium oxide layer comprises: growing a gallium oxide layer with a thickness of 500nm-2500nm under the conditions of a temperature of 1000°C-1200°C, an absolute pressure of 50mbar-100mbar, a gallium source flow rate of 50sccm-500sccm and an oxygen flow rate of 50sccm-100sccm.

11. A gallium oxide thin film, characterized in that: The gallium oxide film is prepared by the preparation method according to any one of claims 1 to 10.

12. An ultraviolet detection device, characterized in that: The ultraviolet detection device comprises a gallium oxide thin film prepared by the preparation method according to any one of claims 1 to 10, or comprises the gallium oxide thin film according to claim 11.

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