Method for doping n-type gallium oxide Si and n-type gallium oxide Si doped material
Si doping is carried out during the growth process of gallium oxide films through electron beam evaporation technology, which solves the problem of modulating the conductivity of gallium oxide materials, achieves uniform distribution and high repeatability of Si elements, and is suitable for industrial production.
Patent Information
- Application Number
- CN202210048361.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-01-17
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2042-01-17
AI Technical Summary
The prior art is difficult to achieve continuous controllable n-type doping and conductive modulation of gallium oxide materials, resulting in limited performance of gallium oxide devices.
Electron beam evaporation technology is used to do Si doping during the growth process of the gallium oxide film. By controlling the electron beam current and carrier concentration, the continuous doping of Si and the adjustable ratio are achieved.
It achieves uniform distribution and high repeatability of Si elements in the material, can continuously adjust the doping ratio, solves the problem of conductivity modulation, and is suitable for industrial production.
Smart Images
Figure CN114400185B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a method for n-type gallium oxide Si doping and an n-type gallium oxide Si doping material. Background Art
[0002] With the rapid development and widespread application of wide bandgap semiconductor devices, more and more attention has been paid to the research of ultra-wide bandgap oxide semiconductor materials. For example, single-crystal gallium oxide is considered to be one of the most promising emerging materials after gallium nitride. However, the key problem that currently limits the performance of gallium oxide devices is the modulation of their conductive properties. How to achieve controllable doping of gallium oxide materials has become a core technology that needs to be broken through.
[0003] Gallium oxide semiconductor materials have a bandgap of 4.8 eV and a Baliga figure of merit of 3214, making them ideal materials for ultraviolet optoelectronics and power devices. However, it is still difficult to achieve continuous and controllable n-type doping, especially the regulation of conductivity by continuous and controllable doping, for the current control of material conductivity. Therefore, it is crucial to develop a simple and effective new technology for continuous and controllable doping to solve the problem of n-type doping and conductivity modulation of gallium oxide.
[0004] As for epitaxially grown gallium oxide thin film materials, the existing doping methods are mainly divided into three categories: (1) Molecular beam epitaxy (MBE) technology uses the k-cell method to discontinuously dope Si to obtain n-type doped gallium oxide. However, the MBE technology Si discontinuous doping method has the problem of uneven distribution of Si in the film. (2) The metal oxide vapor phase epitaxy (MOCVD) method uses silane to dope gallium oxide. However, the C impurities in gallium oxide grown by MOCVD are high, which has a great impact on the doping effect. (3) Magnetron sputtering or pulsed laser epitaxy (PLD) technology is to achieve n-type doping of thin film gallium oxide by pre-doping the target material. The relationship between the doping concentration in the target material of magnetron sputtering or PLD method and the doping actually transferred to the thin film material is relatively complex, and the process conditions have a great impact on it, making it difficult to accurately control.
[0005] In view of this, the present invention is proposed. Summary of the invention
[0006] The purpose of the present invention is to provide a method for doping n-type gallium oxide Si and an n-type gallium oxide Si doped material. The doping method provided in the embodiment of the present invention can realize continuous doping of silicon, and the doping ratio of silicon is continuously adjustable, and the silicon element is evenly distributed in the formed material. At the same time, the process has high repeatability, the size of the prepared material is not limited, and industrial production can be realized.
[0007] The present invention is achieved in that:
[0008] In a first aspect, the present invention provides a method for doping n-type gallium oxide with Si, comprising: doping Si by electron beam evaporation during epitaxial growth of a gallium oxide film on a substrate.
[0009] In an optional embodiment, the method includes: annealing the substrate before performing epitaxial growth.
[0010] In an optional embodiment, the annealing conditions include: a temperature of 900-1400° C. and a time of 2-4 hours;
[0011] Preferably, during the annealing process the substrate is not in contact with an annealing apparatus.
[0012] In an optional embodiment, the method includes: before the annealing treatment, cleaning the substrate;
[0013] Preferably, the cleaning process comprises: cleaning the substrate with a ketone solvent, an alcohol solvent and water in sequence, and then drying.
[0014] In an alternative embodiment, the epitaxial growth is molecular beam epitaxial growth.
[0015] In an optional embodiment, the conditions for epitaxial growth include: the temperature of the gallium source is 900-1100° C., the pressure is 1E-6 to 2E-5 mbar, and the time is 1-6 hours.
[0016] In an optional embodiment, the gallium source used in the epitaxial growth is selected from pure metallic gallium or gallium oxyoxide, and the oxygen source used in the epitaxial chamber is selected from any one of a plasma oxygen source, a gaseous oxygen source and a liquid oxygen source;
[0017] Preferably, the oxygen source is selected from any one of an oxygen plasma source, gaseous ozone and liquid ozone.
[0018] In an optional embodiment, the Si doping source is controlled by electron beam evaporation;
[0019] Preferably, the conditions for electron beam evaporation include: electron beam current of 30-75 mA, carrier concentration of 2.5×10 15 -5×10 20 cm -3 .
[0020] In an optional embodiment, the material forming the substrate is selected from any one of gallium oxide, aluminum oxide and silicon carbide.
[0021] In a second aspect, the present invention provides an n-type gallium oxide Si-doped material, which is prepared by the n-type gallium oxide Si-doping method described in any one of the aforementioned embodiments.
[0022] In a third aspect, the present invention provides a wide bandgap semiconductor device, which includes the n-type gallium oxide Si doped material described in the above embodiment.
[0023] The present invention has the following beneficial effects: The method provided in the embodiment of the present invention utilizes the specific characteristics of electron beam evaporation to perform n-type Si doping, and can achieve continuous and controllable concentration of silicon element doping. The method has high repeatability, the obtained Si doping ratio is continuously adjustable, and is not limited by size, and can achieve industrial production, and the silicon element is evenly distributed in the material formed by the method. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.
[0025] Figure 1 A schematic diagram of a method for Si doping of n-type gallium oxide provided by an embodiment of the present invention;
[0026] Figure 2 A result diagram showing that different electron beam currents can control the amount of Si incorporated in n-type gallium oxide Si doped according to an embodiment of the present invention;
[0027] Figure 3 This is an XRD spectrum of the n-type gallium oxide Si-doped material provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.
[0029] An embodiment of the present invention provides a method for doping n-type gallium oxide Si, comprising:
[0030] First, the substrate is cleaned, and the cleaning step includes sequentially cleaning the substrate with a ketone solvent, an alcohol solvent and water, and then drying. For example, the substrate is ultrasonically cleaned in acetone, isopropanol, alcohol and deionized water for 5-15 minutes each, and then dried with nitrogen.
[0031] The cleaning process can remove stains on the substrate, ensuring that the gallium oxide film formed by subsequent epitaxial growth can be stably combined with the substrate. It is also beneficial to the subsequent doping of silicon elements without introducing impurities, thereby ensuring the performance of the formed material.
[0032] Furthermore, the material forming the substrate is selected from any one of gallium oxide, aluminum oxide and silicon carbide. For example, a sapphire wafer or a gallium oxide wafer can be used.
[0033] It should be noted that the size of the substrate can range from 1 cm*1 cm to several inches, etc., and the size of the substrate is not limited.
[0034] Then, the cleaned substrate is annealed. Specifically, the substrate is placed on a crucible, and the crucible is placed in the constant temperature area of the annealing furnace. During the placement process, the wafer should be prevented from contacting the annealing furnace, and the crucible must be placed in the middle of the constant temperature area. The temperature of the annealing furnace is controlled within the range of 900-1400°C (for example, 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1350°C and 1400°C, etc., any value between 900-1400°C), and after reaching the preset temperature, the temperature is kept for 2-4 hours (for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours and 4 hours, etc., any value between 2-4 hours) to obtain an atomically flat wafer.
[0035] Annealing the substrate can make the substrate surface atomically flat and achieve atomic-level epitaxial growth.
[0036] Next, a gallium oxide thin film is formed by epitaxial growth on the substrate after the annealing treatment, and during the epitaxial growth process, Si is doped by electron beam evaporation. Figure 1 Specifically, the annealed substrate is quickly introduced into the oxide molecular beam epitaxy equipment, and the gallium source temperature is controlled to be 900-1100°C (for example, 900°C, 920°C, 940°C, 960°C, 980°C, 1000°C, 1020°C, 1040°C, 1060°C, 1080°C and 1100°C, etc., any value between 900-1100°C), and an oxygen source is introduced into the chamber to maintain the pressure in the chamber at 1E-6 to 2E-5 mbar. During the epitaxial growth process, the Si doping source is controlled by electron beam evaporation, and the electron beam current is controlled to be 30-75 mA (for example, 30 mA, 35 mA, 40 mA, 45 mA, 50 mA, 55 mA, 60 mA, 65 mA, 70 mA and 75 mA, etc., any value between 35-75 mA), and the carrier concentration is 2.5×10 15 -5×10 20 cm -3(For example, 2.5×10 15 cm -3 , 5×10 15 cm -3 , 1×10 16 cm -3 , 5×10 16 cm -3 , 1×10 17 cm -3 , 5×10 17 cm -3 , 1×10 18 cm -3 , 3×10 18 cm -3 , 5×10 18 cm -3 , 1×10 19 cm -3 , 5×10 19 cm -3 , 1×10 20 cm -3 and 5×10 20 cm -3 2.5×10 15 -5×10 20 cm -3 The gallium oxide film is continuously doped with Si under the above conditions for 1-6 hours (e.g., 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, etc., any value between 1-6 hours) to achieve n-type Si doping of the gallium oxide.
[0037] Furthermore, the gallium source is selected from pure metallic gallium or gallium oxide, the oxygen source is selected from any one of a plasma oxygen source, a gaseous oxygen source and a liquid oxygen source; the oxygen source is selected from any one of an oxygen plasma source, gaseous ozone and liquid ozone.
[0038] In a second aspect, an embodiment of the present invention provides an n-type gallium oxide Si-doped material, which is prepared by the above-mentioned n-type gallium oxide Si-doping method.
[0039] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.
[0040] Example 1
[0041] This embodiment provides a method for doping n-type gallium oxide Si, comprising:
[0042] Sapphire was selected as the substrate. The substrate was ultrasonically cleaned in acetone, isopropanol, alcohol and deionized water for 8 minutes each and then dried with nitrogen. Then the sapphire substrate was placed on the crucible, and the crucible was placed in the constant temperature area of the annealing furnace. During the placement process, the wafer should be prevented from contacting the annealing furnace, and the crucible must be placed in the middle of the constant temperature area. The temperature of the annealing furnace was controlled at 1000°C, and it was kept warm for 4 hours after reaching the preset temperature to obtain an atomically flat wafer. Subsequently, the processed substrate was quickly transferred to the oxide molecular beam epitaxy equipment, and the gallium source (gallium source is Ga metal) temperature was controlled at 1020°C. At the same time, an oxygen source (ozone or plasma oxygen source) was introduced into the chamber to maintain the pressure in the chamber at 5E-6-2E-5Pa. During the epitaxial growth process, the technology uses electron beam evaporation to control the Si doping source, and the electron beam current is controlled at 50mA to continuously dope Si into the gallium oxide film. Under the above conditions, the epitaxy was performed for 4 hours to achieve n-type Si doping of gallium oxide.
[0043] This embodiment provides an n-type gallium oxide Si-doped material, which is prepared by the method of this embodiment.
[0044] Example 2-Example 8
[0045] Examples 2 to 8 all provide a method for n-type gallium oxide Si doping, which is basically the same as the method of Example 1 in operation, except that the current of the electron beam used in the electron beam evaporation is different, see Table 1 for details.
[0046] Example 9
[0047] This embodiment provides a method for doping n-type gallium oxide Si, comprising:
[0048] Sapphire was selected as the substrate. The substrate was ultrasonically cleaned in acetone, isopropanol, alcohol and deionized water for 15 minutes each and then dried with nitrogen. Then the sapphire substrate was placed on the crucible, and the crucible was placed in the constant temperature area of the annealing furnace. During the placement process, the wafer should be prevented from contacting the annealing furnace, and the crucible must be placed in the middle of the constant temperature area. The temperature of the annealing furnace was controlled at 1000°C, and after reaching the preset temperature, it was kept warm for 4 hours to obtain an atomically flat wafer. Subsequently, the processed substrate was quickly transferred to the oxide molecular beam epitaxy equipment, and the gallium source (gallium source is Ga metal) temperature was controlled at 1060°C. At the same time, an oxygen source (ozone or plasma oxygen source) was introduced into the chamber to maintain the pressure in the chamber at 5E-6-2E-5Pa. During the epitaxial growth process, the technology uses electron beam evaporation to control the Si doping source, and the electron beam current is controlled at 60mA to continuously dope Si into the gallium oxide film. Under the above conditions, the epitaxy was performed for 3 hours to achieve n-type Si doping of gallium oxide.
[0049] This embodiment provides an n-type gallium oxide Si-doped material, which is prepared by the method of this embodiment.
[0050] Example 10
[0051] This embodiment provides a method for doping n-type gallium oxide Si, comprising:
[0052] Sapphire was selected as the substrate. The substrate was ultrasonically cleaned in acetone, isopropanol, alcohol and deionized water for 10 minutes each and then dried with nitrogen. Then the sapphire substrate was placed on the crucible, and the crucible was placed in the constant temperature area of the annealing furnace. During the placement process, the wafer should be prevented from contacting the annealing furnace, and the crucible must be placed in the middle of the constant temperature area. The temperature of the annealing furnace was controlled at 1000°C, and it was kept warm for 6 hours after reaching the preset temperature to obtain an atomically flat wafer. Subsequently, the processed substrate was quickly transferred to the oxide molecular beam epitaxy equipment, and the gallium source (gallium source is Ga metal) temperature was controlled at 960°C. At the same time, an oxygen source (ozone or plasma oxygen source) was introduced into the chamber to maintain the chamber pressure at 5E-6-2E-5Pa. During the epitaxial growth process, the technology uses electron beam evaporation to control the Si doping source, and the electron beam current is controlled at 30mA to continuously dope Si into the gallium oxide film. Under the above conditions, the epitaxy was performed for 6 hours to achieve n-type Si doping of gallium oxide.
[0053] This embodiment provides an n-type gallium oxide Si-doped material, which is prepared by the method of this embodiment.
[0054] Detection 1
[0055] The current carrier concentrations of Examples 1-8 were detected, and the specific results are shown in Table 1.
[0056] Table 1
[0057]
[0058]
[0059] According to Table 1, different currents can achieve different Si incorporation, and ultimately achieve control of carrier concentration. Figure 2 It was demonstrated that different electron beam currents can control the amount of Si incorporated.
[0060] Detection 2
[0061] X-ray diffraction was performed on the n-type gallium oxide Si-doped materials of Examples 1-8. The test results are shown in Figure 3 ,according to Figure 3 It can be seen that the electron beam current can control the incorporation of Si to a certain amount without changing the material quality. When it exceeds a certain amount, that is, the electron beam current reaches 75 mA, serious segregation of other crystal phases will occur, which is not conducive to improving the material quality.
[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for doping n-type gallium oxide Si, characterized in that: include: In the process of epitaxially growing a gallium oxide film on a substrate, electron beam evaporation is used to dope Si; Wherein, the substrate is subjected to annealing treatment before epitaxial growth; The conditions for epitaxial growth include: a gallium source temperature of 900-1100°C, a pressure of 1E-6 to 2E-5 mbar, and a time of 1-6 hours; The Si doping source is controlled by electron beam evaporation; The conditions for electron beam evaporation include: electron beam current is 30-75 mA.
2. The method for doping n-type gallium oxide Si according to claim 1, characterized in that: The annealing conditions include: a temperature of 900-1400° C. and a time of 2-4 hours.
3. The method for doping n-type gallium oxide Si according to claim 1, characterized in that: During the annealing process the substrate is not in contact with the equipment performing the annealing process.
4. The method for doping n-type gallium oxide Si according to claim 2, characterized in that: include: Before the annealing process, the substrate is cleaned.
5. The method for doping n-type gallium oxide Si according to claim 4, characterized in that: The cleaning process includes: using a ketone solvent, an alcohol solvent and water to clean the substrate in sequence, and then drying.
6. The method for doping n-type gallium oxide Si according to claim 1, characterized in that: The epitaxial growth is molecular beam epitaxial growth.
7. The method for doping n-type gallium oxide Si according to claim 1, characterized in that: The gallium source used in epitaxial growth is selected from pure metallic gallium or gallium oxyoxide, and the oxygen source used in the epitaxial chamber is selected from any one of a plasma oxygen source, a gaseous oxygen source and a liquid oxygen source.
8. The method for doping n-type gallium oxide Si according to claim 7, characterized in that: The oxygen source is selected from any one of an oxygen plasma source, gaseous ozone and liquid ozone.
9. The method for doping n-type gallium oxide Si according to claim 7, characterized in that: The material forming the substrate is selected from any one of gallium oxide, aluminum oxide and silicon carbide.
10. An n-type gallium oxide Si-doped material, characterized in that: The n-type gallium oxide is prepared by the Si-doping method described in any one of claims 1 to 9.
11. A wide bandgap semiconductor device, characterized in that: It comprises the n-type gallium oxide Si-doped material as claimed in claim 10.