A deep ultraviolet transparent high conductivity gallium oxide electrode and its preparation method

Abstract

This invention relates to the field of transparent conductive electrodes, specifically disclosing a deep ultraviolet transparent high-conductivity gallium oxide electrode and its fabrication method. The electrode includes a substrate and a high-conductivity gallium oxide epitaxial film formed thereon. The epitaxial film has a high carrier concentration, high mobility, and low resistivity. The fabrication method includes: providing a substrate; providing a metal source precursor formed by powder-coated metal, an oxygen source gas, and a dopant; and using a vapor-phase epitaxy process, under conditions of 900-1400℃ in the growth region and 1100-1500℃ in the source region, transporting gaseous gallium suboxide and gaseous dopant to the substrate surface via a carrier gas to react and grow with the oxygen source gas.

Description

Technical Field

[0001] This invention belongs to the field of transparent conductive electrodes, specifically a deep ultraviolet transparent highly conductive gallium oxide electrode and its preparation method. Background Technology

[0002] Transparent conductive electrodes are core components of optoelectronic devices, and their performance directly affects device efficiency. In deep ultraviolet applications, traditional materials such as ITO, FTO, and AZO are no longer sufficient due to intrinsic absorption limitations. Gallium oxide... With its unique 4.9 eV wide bandgap characteristic, it has become an ideal alternative material. This material system simultaneously possesses high light transmittance and tunable conductivity, and has enormous application potential in the field of optoelectronic materials and devices. , , n-type doped gallium oxide can achieve carrier concentrations of up to Compared to traditional transparent conductive materials, β-phase gallium oxide exhibits a high breakdown field strength of 8 MV / cm and a melting point of ~1800℃, demonstrating significant advantages in high-temperature, high-power, and strong-radiation environments. This technology shows important application value in fields such as deep ultraviolet detectors, deep ultraviolet LEDs, and military early warning systems. Currently, the main technologies for preparing conductive gallium oxide epitaxial films include metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and pulsed laser deposition (PLD). However, these technologies require expensive equipment, are complex to operate, and operate under harsh conditions. The equipment structure and gas path are complex, and it is difficult to grow highly conductive gallium oxide epitaxial films with high carrier concentration and high mobility. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a deep ultraviolet transparent high-conductivity gallium oxide electrode and its preparation method, thereby solving the problems of traditional transparent conductive electrodes being opaque in the deep ultraviolet band, having high preparation costs, complex preparation processes, and difficulty in simultaneously obtaining high carrier concentration and high mobility.

[0004] This invention provides a deep ultraviolet transparent high conductivity gallium oxide electrode, comprising:

[0005] A substrate and a highly conductive gallium oxide epitaxial film formed on the substrate;

[0006] The carrier concentration of the highly conductive gallium oxide epitaxial film is higher than The migration rate is higher than Resistivity is lower than .

[0007] Preferably, the substrate includes any one of a gallium oxide single crystal substrate with arbitrary crystal orientation, a heterogeneous substrate, or a heterogeneous substrate having a gallium oxide homogeneous buffer layer.

[0008] Preferably, the heterostructure substrate is a c-plane sapphire single crystal substrate with an oblique cut of 0°~6° along the a-axis, or a (100) plane. Any one of the following: single crystal substrate, r-plane sapphire single crystal substrate, m-plane sapphire single crystal substrate, a-plane sapphire single crystal substrate, or (001)-plane yttrium-stabilized zirconium oxide single crystal substrate.

[0009] The present invention also provides a method for preparing a deep ultraviolet transparent high conductivity gallium oxide electrode as described above, comprising the following steps:

[0010] S1. Provide a substrate;

[0011] S2, providing metal Oxygen source precursor, oxygen source gas, and dopant;

[0012] S3. Employs vapor phase epitaxy (VPE) with metal... Highly conductive gallium oxide epitaxial films are grown on substrate surfaces using source precursors, oxygen source gas, and dopants as raw materials.

[0013] Preferably, in step S2, the metal Source precursor as Metal with uniform powder coating Small droplets, the dopant being , , It may contain at least one of its oxides in various valence states or may not use any dopant.

[0014] Preferably, the dopant and The molar ratio of the elements is (0:100) to (10:90), the aforementioned Powder and Metal The molar ratio is 1:1 to 1:6.

[0015] Preferably, in step S3, the vapor phase epitaxy process is carried out in a multi-temperature zone crystal growth furnace;

[0016] The multi-temperature zone crystal growth furnace includes a source region and a growth region, as well as an outer tube and an inner tube;

[0017] The built-in tube is used for introducing carrier gas and loading metal. The precursor contains an interlayer formed between the outer wall of the inner tube and the outer tube, which is used to introduce oxygen source gas.

[0018] The built-in tube has a flow guide port on the side near the growth zone.

[0019] Preferably, step S3 specifically includes:

[0020] S31. Place the substrate in the growth region and apply the metal. A mixture of source precursor and dopant is placed in the source region;

[0021] S32. After evacuation, fill with inert gas to near atmospheric pressure;

[0022] S33. Heat the growth zone to 900~1400℃ and the source zone to 1100~1500℃;

[0023] S34. Introduce carrier gas and oxygen source gas to transport gaseous gallium suboxide and gaseous dopant to the substrate surface to grow a highly conductive gallium oxide epitaxial film.

[0024] Preferably, both the carrier gas and the inert gas are... or At least one of the following, wherein the oxygen source gas is .

[0025] Preferably, during the growth process, the flow ratio of carrier gas to oxygen source gas is 4:1 to 4:5, and the gas pressure inside the multi-temperature zone crystal growth furnace is controlled at... .

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

[0027] The deep ultraviolet transparent high conductivity gallium oxide electrode provided by this invention uses a strongly reducing suboxide. O source and weak oxidizing O source Gallium is grown and donor doped. Under these preparation conditions, gallium interstitial (GaN) ) and oxygen vacancy ( It has a low formation energy and is prone to spontaneous formation. As a donor defect occupying a gap-filling position, In a high-energy state within the crystal lattice, there is a tendency to ionize and release electrons to lower the system energy; the released free electrons enhance n-type conductivity. This is also a defect of the donor, equivalent to removal. An O atom in the crystal lattice leaves behind electrons. These electrons are easily excited to the conduction band at room temperature, becoming free electrons, thereby increasing the electron concentration and enhancing n-type conductivity; simultaneously, by... Incorporating donor dopant, the donor doped atoms ionize towards The lattice introduces additional electrons, further enhancing n-type conductivity. The synergistic effect of these three conductivity mechanisms results in a total electron concentration exceeding that provided by conventional doping relying solely on a single conductivity mechanism. As a result, the deep ultraviolet transparent, highly conductive gallium oxide electrode prepared by this invention exhibits a significantly higher electron concentration than electrodes prepared using conventional techniques. The electron concentration of the epitaxial film can reach... The deep ultraviolet transparent high conductivity gallium oxide electrode prepared by this invention is (-310) oriented. The single crystal, without any post-processing, exhibits a rocking curve full width at half maximum (FWHM) of as low as 0.102° on the (-620) crystal plane, demonstrating excellent crystal quality. Thanks to this superior crystal quality, its electron mobility is significantly higher than that of conductive materials prepared using traditional methods. The electron mobility of epitaxial films can reach The combined effect of high electron concentration and high mobility gives the deep ultraviolet transparent high-conductivity gallium oxide electrode of this invention a higher conductivity than that produced by traditional processes. Epitaxial films have even lower resistivity, with resistivity as low as [missing information]. Combining With an ultrawide direct bandgap of ~4.9 eV, the deep ultraviolet transparent high-conductivity gallium oxide electrode prepared by this invention exhibits excellent transmittance to deep ultraviolet light, with a transmittance exceeding 40% for light in the 260 nm~320 nm wavelength range. Compared to traditional transparent electrodes (such as ITO, FTO, and AZO), the deep ultraviolet transparent high-conductivity gallium oxide electrode of this invention not only expands the application range of transparent electrodes in the 260 nm~320 nm ultraviolet light range but also meets the application requirements for high conductivity.

[0028] The method for preparing a deep ultraviolet transparent high conductivity gallium oxide electrode provided by this invention requires simple equipment and operating procedures, and the raw materials are inexpensive and readily available, which can meet the requirements of large-scale industrial production. Attached Figure Description

[0029] Figure 1 This is a process flow diagram of the preparation method of the deep ultraviolet transparent highly conductive gallium oxide electrode of the present invention;

[0030] Figure 2 This is a simplified structural diagram of the deep ultraviolet transparent high conductivity gallium oxide electrode fabrication device of the present invention;

[0031] Figure 3 The image shows an HADDF-STEM atomic-resolution image of the interface of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 1 of this invention, and a fast Fourier transform spectrum of the gallium oxide region.

[0032] Figure 4 The images show HADDF-STEM atomic-resolution images of the unfilled and filled defect regions of the deep ultraviolet transparent high-conductivity gallium oxide electrode prepared in Example 1 of the present invention, along with their corresponding intensity contours.

[0033] Figures 5a-5e The XRD patterns of the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 1-5 of this invention were tested respectively.

[0034] Figures 6a-6e The XRD rocking curves of the (-620) crystal plane of the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 1-5 of the present invention are respectively tested.

[0035] Figures 7a-7e The transmission spectra of the deep ultraviolet transparent highly conductive gallium oxide electrodes prepared in Examples 1-5 of this invention were measured respectively.

[0036] Figures 8a-8e The deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 1-5 of this invention were tested respectively. and Relationship diagram;

[0037] Figures 9a-9b The image shows the Hall effect ohmic contact detection IV characteristic curves of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Examples 1-2 of this invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] In the field of materials science, the determination of semiconductor band gap by transmittance is usually based on the Tauc plot method, which first uses the transmittance T and sample thickness d to determine the band gap using the formula... Calculate the absorption coefficient Then, based on the type of interband transition (direct bandgap) Indirect band gap Constructing Tauc Relations Finally, through drawing Photon energy The relationship curve is obtained by extrapolating the linear portion to the intersection of the horizontal axis, thereby obtaining the optical bandgap. The optical band gap of the gallium oxide epitaxial film in this invention is calculated using this method.

[0040] This invention provides a deep ultraviolet transparent high-conductivity gallium oxide electrode, wherein the electrode comprises a substrate and a high-conductivity gallium oxide epitaxial film formed on the substrate. The carrier concentration of the high-conductivity gallium oxide epitaxial film is higher than that of the substrate. The migration rate is higher than Resistivity is lower than .

[0041] Preferably, the substrate includes any one of a gallium oxide single crystal substrate with arbitrary crystal orientation, a heterogeneous substrate, or a heterogeneous substrate having a gallium oxide homogeneous buffer layer.

[0042] Preferably, the heterostructure substrate is a c-plane sapphire single crystal substrate with an oblique cut of 0°~6° along the a-axis, or a (100) plane. Any one of the following: single crystal substrate, r-plane sapphire single crystal substrate, m-plane sapphire single crystal substrate, a-plane sapphire single crystal substrate, or (001)-plane yttrium-stabilized zirconium oxide single crystal substrate.

[0043] It should be noted that the deep ultraviolet transparent high conductivity gallium oxide electrode provided by this invention uses a strongly reducing suboxide. O source and weak oxidizing O source Gallium is grown and donor doped. Under these preparation conditions, gallium interstitial (GaN) ) and oxygen vacancy ( It has a low formation energy and is prone to spontaneous formation. As a donor defect occupying a gap-filling position, In a high-energy state within the crystal lattice, there is a tendency to ionize and release electrons to lower the system energy; the released free electrons enhance n-type conductivity. This is also a defect of the donor, equivalent to removal. An O atom in the crystal lattice leaves behind electrons. These electrons are easily excited to the conduction band at room temperature, becoming free electrons, thereby increasing the electron concentration and enhancing n-type conductivity; simultaneously, by... Incorporating donor dopant, the donor doped atoms ionize towards The lattice introduces additional electrons, further enhancing n-type conductivity. The three conductivity mechanisms work synergistically, resulting in a total electron concentration exceeding that provided by conventional doping relying solely on a single conductivity mechanism. The deep ultraviolet transparent, highly conductive gallium oxide electrode prepared in this invention has a (-310) orientation. Single crystals possess excellent crystal quality, resulting in a much higher electron mobility than conductive materials prepared using traditional methods. Electron mobility of the epitaxial film. The combined effect of high electron concentration and high mobility gives the deep ultraviolet transparent high conductivity gallium oxide electrode of this invention a higher conductivity than that produced by traditional processes. The epitaxial film has lower resistivity. Combined with... With the advantage of an ultrawide direct bandgap of ~4.9 eV, the deep ultraviolet transparent high conductivity gallium oxide electrode prepared by this invention has good transmittance to deep ultraviolet light.

[0044] Based on the same inventive concept, this invention provides a method for preparing a gallium oxide-based deep ultraviolet transparent conductive epitaxial film, such as... Figure 1 As shown, it includes the following steps:

[0045] S1. Provide a substrate;

[0046] S2, providing metal Oxygen source precursor, oxygen source gas, and dopant;

[0047] S3. Employs vapor phase epitaxy (VPE) with metal... Highly conductive gallium oxide epitaxial films are grown on substrate surfaces using source precursors, oxygen source gas, and dopants as raw materials.

[0048] Preferably, in step S2, the metal Source precursor as Metal with uniform powder coating Small droplets, the dopant being , , It may contain at least one of its oxides in various valence states or may not use any dopant.

[0049] Preferably, the dopant and The molar ratio of the elements is (0:100) to (10:90), the aforementioned Powder and Metal The molar ratio is 1:1 to 1:6.

[0050] Step S2, in some embodiments, specifically means: no dopant.

[0051] at this time, The main chemical reactions upon which source gas phase transport depends are:

[0052]

[0053] Step S2, in some embodiments, specifically involves: the dopant being... .

[0054] at this time, dopants The main chemical reactions upon which source gas phase transport depends are:

[0055]

[0056]

[0057] Step S2, in some embodiments, specifically involves: the dopant being Sn and... .

[0058] at this time, dopants The main chemical reactions upon which source gas phase transport depends are:

[0059]

[0060]

[0061] Step S2, in some embodiments, specifically involves: the dopant being... and .

[0062] at this time, dopants The main chemical reactions upon which source gas phase transport depends are:

[0063]

[0064]

[0065] Step S3, in some embodiments, specifically means: no dopant.

[0066] At this point, the main chemical reaction upon which the growth of undoped, highly conductive gallium oxide epitaxial films depends is:

[0067]

[0068] Step S3, in some embodiments, specifically involves: the dopant being... .

[0069] At this point, the main chemical reaction upon which the growth of Si-doped highly conductive gallium oxide epitaxial films depends is:

[0070]

[0071] Step S3, in some embodiments, specifically involves: the dopant being Sn and... .

[0072] At this point, the main chemical reaction upon which the growth of Sn-doped highly conductive gallium oxide epitaxial film depends is:

[0073]

[0074] Step S3, in some embodiments, specifically involves: the dopant being Ge and .

[0075] At this point, the main chemical reaction upon which the growth of Ge-doped highly conductive gallium oxide epitaxial films depends is:

[0076]

[0077] Step S3, in some embodiments, specifically involves: the vapor phase epitaxy process being performed in a multi-temperature zone crystal growth furnace, the simplified structure of which is shown in the figure below. Figure 2 As shown.

[0078] Preferably, the multi-temperature zone crystal growth furnace includes a source zone and a growth zone, as well as an outer tube and an inner tube.

[0079] Preferably, the multi-temperature zone crystal growth furnace further includes an outer tube for constructing the chamber required for growing a highly conductive gallium oxide epitaxial film, and a tube for introducing a carrier gas and loading the metal. The source precursor has an internal tube, the outer wall of which forms an interlayer with the inner wall of the outer tube, the interlayer being used to introduce the oxygen source gas.

[0080] Preferably, the built-in tube includes a support for the metal. The source precursor crucible and the conduit connected to the crucible are provided with a flow guide on the side of the conduit near the substrate. The flow guide is located in the growth region, specifically 5-7 cm away from the substrate.

[0081] Preferably, metal The source precursor is transferred to the crucible in the source region of the multi-temperature zone crystal growth furnace, while the substrate is placed in the growth region of the multi-temperature zone crystal growth furnace.

[0082] Specifically, before placing the substrate in the growth zone of the multi-temperature zone crystal growth furnace, the process also includes: sequentially cleaning the substrate with acetone, anhydrous ethanol, and deionized water, and then using high-purity... Gas is blown dry to ensure the cleanliness of the substrate.

[0083] Preferably, the multi-temperature zone crystal growth furnace is subjected to vacuum treatment, and both the source region and the growth region are heated from room temperature.

[0084] Specifically, this step also includes:

[0085] First, the multi-temperature zone crystal growth furnace is evacuated to bring the internal pressure to the limit pressure of the evacuation equipment (0.01~5 Pa). Then, the temperature of the multi-temperature zone crystal growth furnace is increased from room temperature to a first preset temperature at a rate of 2~5℃ / min using the furnace's heating program. This first preset temperature does not exceed the metal's... The temperature at which the precursor reacts. Preferably, the first preset temperature is 150°C to 200°C. During the above heating process, continuous evacuation is maintained to keep the gas pressure inside the multi-temperature zone crystal growth furnace at 0.01 to 5 Pa, which helps to remove air and other impurity gases from the multi-temperature zone crystal growth furnace and create a clean environment.

[0086] Inert gas is introduced into the multi-temperature zone crystal growth furnace, and the growth zone is heated to 900~1400℃, while the source zone is heated to 1100~1500℃.

[0087] Specifically, when the temperature of the multi-zone crystal growth furnace reaches the first preset temperature, 1 atm of inert gas is introduced into the furnace and all gas valves are closed to bring the gas pressure inside the furnace to near atmospheric pressure. Introducing inert gas at this time serves to protect and stabilize the reaction environment, preventing metal from entering the furnace. The source precursor evaporates in large quantities during the heating process, which would otherwise waste raw materials. This ensures the utilization rate of raw materials for subsequent single crystal growth and reduces production costs.

[0088] Then, the temperature of the source region is raised from the first preset temperature to 1100-1500℃ at a heating rate of 5-10℃ / min using the heating program of the multi-temperature zone crystal growth furnace. At the same time, the temperature of the growth region is raised from the first preset temperature to 900-1400℃ at a heating rate of 5-10℃ / min using the heating program of the multi-temperature zone crystal growth furnace, so as to ensure that the temperature of the source region is higher than that of the growth region.

[0089] In this step, by setting the temperature of the source region higher than that of the growth region, the required temperature distribution for the reaction is provided. On the one hand, the higher temperature accelerates the evaporation rate of the metal suboxides, allowing them to be transported to the substrate surface more quickly. On the other hand, when the oxygen source gas is... At that time, ensure The metal suboxide exhibits reducing properties in the source region and oxidizing properties in the growth region, thus making it almost unaffected by the metal suboxide in the source region. The reaction occurs on the substrate surface with... A reaction occurs.

[0090] Keeping the source and growth regions at constant temperatures, a carrier gas and an oxygen source gas are introduced into the multi-temperature zone crystal growth furnace. The carrier gas carries the metal... The metal suboxide formed by the reaction of the source precursor after heating is directionally transported to the substrate surface, fully mixed with the oxygen source gas, and an oxide epitaxial film is grown on the substrate surface.

[0091] Specifically, this step also includes: first, maintaining the temperature of each zone in the multi-temperature zone crystal growth furnace constant, continuously introducing carrier gas into the internal tube, and continuously introducing oxygen source gas or a mixture of oxygen source gas and inert gas in any proportion into the interlayer; the reacted gas is continuously discharged through the exhaust port below the growth zone; wherein the carrier gas and inert gas are both... as well as At least one of them, the oxygen source gas is .

[0092] Specifically, the carrier gas will carry the metal The gaseous metal suboxides or solid or liquid metal suboxides with high saturated vapor pressure formed by the reaction of the source precursor after heating are directionally transported to the substrate of the growth zone. Oxygen source gas enters the substrate of the growth zone from the interlayer, and the two are uniformly mixed. At this time, the gas pressure inside the multi-temperature zone crystal growth furnace is atmospheric pressure or near-atmospheric pressure. Specifically… The reaction time is 10~60 min, and a deep ultraviolet transparent high conductivity gallium oxide electrode epitaxial film is obtained.

[0093] Specifically, in order to improve the crystal quality of epitaxial films and study the conductivity mechanism, the samples can be annealed.

[0094] The following specific embodiments further illustrate the deep ultraviolet transparent highly conductive gallium oxide electrode and its preparation method of the present invention.

[0095] Example 1: This invention provides a deep ultraviolet transparent high conductivity gallium oxide electrode, wherein the deep ultraviolet transparent high conductivity gallium oxide electrode is an undoped electrode grown on a substrate. Epitaxial film, the chemical formula of the epitaxial film is .

[0096] It should be noted that the deep ultraviolet transparent highly conductive gallium oxide electrode provided in Example 1 uses a strongly reducing suboxide. source With weak oxidizing O source Growth. Under these preparation conditions, gallium interstitial ( ) and oxygen vacancy ( It has a low formation energy and is prone to spontaneous formation. As a donor defect occupying a gap-filling position, In a high-energy state within the crystal lattice, there is a tendency to ionize and release electrons to lower the system energy; the released free electrons enhance n-type conductivity. This is also a defect of the donor, equivalent to removal. An O atom in the crystal lattice leaves behind electrons. These electrons are easily excited to the conduction band at room temperature, becoming free electrons, thereby increasing the electron concentration and enhancing n-type conductivity.

[0097] Based on the same inventive concept, this invention provides a method for preparing a gallium oxide-based deep ultraviolet transparent conductive epitaxial film, such as... Figure 1 As shown, it includes the following steps:

[0098] S1. Provide a sapphire single crystal substrate with a c-plane obliquely cut at 6° along the a-axis. Clean the c-plane sapphire single crystal substrate with a c-plane obliquely cut at 6° along the a-axis sequentially using acetone, anhydrous ethanol, and deionized water, and then use high-purity... Dry the gas and set aside for later use.

[0099] S2, providing metal Source precursor. Powder and Metal The molar ratio is 1:(1~6), providing oxygen source gas.

[0100] S3. Utilizing vapor phase epitaxy (VPE) technology, with metal... Highly conductive gallium oxide epitaxial films are grown on the substrate surface using source precursors and oxygen source gas as raw materials.

[0101] Specifically, step S2 involves: metal Source precursor as Metal with uniform powder coating Small droplets; the aforementioned high-purity metal Small particles of elemental and high purity The powders were purchased from the market or produced through simple processing, and their price was much lower than that of high-valence stable phase gallium oxide single crystals.

[0102] Preferably, Powder and metallic elements The molar ratio of the particles is 1:4; at this time, Powder, metal The elemental particles react at high temperature to generate gaseous gallium suboxide, which is then transported to the substrate surface by the carrier gas.

[0103] In step S3, vapor phase epitaxy is used to extract metal... Using source precursors and oxygen source gas as raw materials, a highly conductive gallium oxide epitaxial film is grown on the substrate surface, specifically as follows:

[0104] metal The source precursor is transferred to the crucible in the source region of the multi-temperature zone crystal growth furnace, while the substrate is placed in the growth region of the multi-temperature zone crystal growth furnace.

[0105] In this embodiment of the invention, the multi-temperature zone crystal growth furnace further includes an outer tube for constructing the chamber required for growing a highly conductive gallium oxide epitaxial film, and a tube for introducing a carrier gas and loading the metal. The source precursor has an internal tube, the outer wall of which forms an interlayer with the inner wall of the outer tube, the interlayer being used to introduce the oxygen source gas.

[0106] Specifically, the built-in tube includes a structure for carrying the metal. The source precursor crucible and the conduit connected to the crucible are provided with a flow guide on the side of the conduit near the substrate. The flow guide is located in the growth region, specifically 5 cm away from the substrate.

[0107] The multi-temperature zone crystal growth furnace was evacuated, and both the source region and the growth region were heated from room temperature.

[0108] Specifically, this step also includes:

[0109] First, the multi-zone crystal growth furnace is evacuated to bring the internal pressure to the vacuum equipment's limit of 0.01 Pa. Then, the furnace temperature is increased from room temperature to 150°C at a rate of 5°C / min using the furnace's heating program. Throughout this heating process, continuous evacuation is maintained to keep the internal pressure at 0.01 Pa, which helps to remove air and other impurities, creating a clean environment.

[0110] An inert gas was introduced into the multi-temperature zone crystal growth furnace, and the growth zone was heated to 1000°C, while the source zone was also heated to 1000°C.

[0111] Specifically, when the temperature of the multi-zone crystal growth furnace reaches 150℃, 1 atm of inert gas is introduced into the furnace and all gas valves are closed to bring the gas pressure inside the furnace to near atmospheric pressure. Introducing inert gas at this point can protect and stabilize the reaction environment, preventing metal from entering the furnace. The source precursor evaporates in large quantities during the heating process, which would otherwise waste raw materials. This ensures the utilization rate of raw materials for subsequent single crystal growth and reduces production costs.

[0112] Then, the temperature of the source region is raised from 1000℃ to 1400℃ at a heating rate of 5℃ / min using the heating program of the multi-temperature zone crystal growth furnace. At the same time, the temperature of the growth region is raised from 1000℃ to 1300℃ at a heating rate of 5℃ / min using the heating program of the multi-temperature zone crystal growth furnace, so as to ensure that the temperature of the source region is higher than that of the growth region.

[0113] In this step, by setting the temperature of the source region higher than that of the growth region, the required temperature distribution for the reaction is provided. On the one hand, the higher temperature accelerates the evaporation rate of the metal suboxides, allowing them to be transported to the substrate surface more quickly. On the other hand, when the oxygen source gas is... At that time, ensure The metal suboxide exhibits reducing properties in the source region and oxidizing properties in the growth region, thus making it almost unaffected by the metal suboxide in the source region. The reaction occurs on the substrate surface with... A reaction occurs.

[0114] Keeping the source and growth regions at constant temperatures, a carrier gas and an oxygen source gas are introduced into the multi-temperature zone crystal growth furnace. The carrier gas carries the metal... The metal suboxide formed by the reaction of the source precursor after heating is directionally transported to the substrate surface, fully mixed with the oxygen source gas, and an oxide epitaxial film is grown on the substrate surface.

[0115] Specifically, this step also includes: first, maintaining the temperature of each zone in the multi-temperature zone crystal growth furnace constant, continuously introducing carrier gas into the internal tube and continuously introducing oxygen source gas into the interlayer, with a carrier gas to oxygen source gas flow ratio of 4:3; and continuously discharging the reacted gas through the exhaust port below the growth zone; wherein the carrier gas and the inert gas are both... The oxygen source gas is .

[0116] Specifically, the carrier gas will carry the metal The gaseous metal suboxides or solid or liquid metal suboxides with high saturated vapor pressure formed by the reaction of the source precursor after heating are directionally transported to the substrate of the growth zone. Oxygen source gas enters the substrate of the growth zone from the interlayer, and the two are uniformly mixed. At this time, the gas pressure inside the multi-temperature zone crystal growth furnace is atmospheric pressure or near-atmospheric pressure. Specifically… .

[0117] The selected samples were annealed. Specifically, the annealing temperature was 1300℃, the annealing time was 6 h, and the annealing pressure was 1.2 atm. Atmosphere.

[0118] Example 2: This invention provides a deep ultraviolet transparent high conductivity gallium oxide electrode, wherein the deep ultraviolet transparent high conductivity gallium oxide electrode is... Doped An n-type conductive epitaxial film or a pure gallium oxide epitaxial film, wherein the chemical formula of the conductive epitaxial film is [formula missing]. .

[0119] It should be noted that, based on Example 1, Example 2 involves... Incorporation of donor dopant , Atomic ionization The lattice introduces additional electrons, further enhancing n-type conductivity.

[0120] Based on the same inventive concept, this invention provides a method for preparing a gallium oxide-based deep ultraviolet transparent conductive epitaxial film, such as... Figure 1 As shown, it includes the following steps:

[0121] S1. Provide a sapphire single crystal substrate with a c-plane obliquely cut at 6° along the a-axis. Clean the c-plane sapphire single crystal substrate with a c-plane obliquely cut at 6° along the a-axis sequentially using acetone, anhydrous ethanol, and deionized water, and then use high-purity... Dry the gas and set aside for later use.

[0122] S2, providing dopant Powder, metal Source precursor, Powder and Metal The molar ratio of the source precursor is (0:100) to (10:90). Powder and Metal The molar ratio is 1:(1~6), providing oxygen source gas.

[0123] S3. Utilizing vapor phase epitaxy (VPE) technology, with metal... Highly conductive gallium oxide epitaxial films are grown on substrate surfaces using source precursors, oxygen source gas, and dopants as raw materials.

[0124] Specifically, step S2 involves: metal Source precursor as Metal with uniform powder coating Small droplets; the aforementioned high-purity metal Small particles of elemental and high purity Powders and high-purity elements The powder is purchased from the market or produced through simple processing, and its price is much lower than that of high-valence stable phase gallium oxide single crystal.

[0125] Preferably, metal In the source precursor Powder and Metal and The molar ratio of the powders is (1:99). Powder and metallic elements The molar ratio of the particles is 1:4; at this point, an appropriate amount pink, Powder, metal The elemental particles react at high temperature to generate gaseous gallium suboxide and gaseous dopant, which are then transported to the substrate surface by the carrier gas.

[0126] In step S3, vapor phase epitaxy is used to extract metal... Using source precursors, oxygen source gas, and dopants as raw materials, a highly conductive gallium oxide epitaxial film is grown on the substrate surface, specifically as follows:

[0127] metal The source precursor is transferred to the crucible in the source region of the multi-temperature zone crystal growth furnace, while the substrate is placed in the growth region of the multi-temperature zone crystal growth furnace.

[0128] In this embodiment of the invention, the multi-temperature zone crystal growth furnace further includes an outer tube for constructing the chamber required for growing a highly conductive gallium oxide epitaxial film, and a tube for introducing a carrier gas and loading the metal. The source precursor has an internal tube, the outer wall of which forms an interlayer with the inner wall of the outer tube, the interlayer being used to introduce the oxygen source gas.

[0129] Specifically, the built-in tube includes a structure for carrying the metal. The source precursor crucible and the conduit connected to the crucible are provided with a flow guide on the side of the conduit near the substrate. The flow guide is located in the growth region, specifically 5 cm away from the substrate.

[0130] The multi-temperature zone crystal growth furnace was evacuated, and both the source region and the growth region were heated from room temperature.

[0131] Specifically, this step also includes:

[0132] First, the multi-zone crystal growth furnace is evacuated to bring the internal pressure to the vacuum equipment's limit of 0.01 Pa. Then, the furnace temperature is increased from room temperature to 150°C at a rate of 5°C / min using the furnace's heating program. Throughout this heating process, continuous evacuation is maintained to keep the internal pressure at 0.01 Pa, which helps to remove air and other impurities, creating a clean environment.

[0133] An inert gas was introduced into the multi-temperature zone crystal growth furnace, and the growth zone was heated to 1000°C, while the source zone was also heated to 1000°C.

[0134] Specifically, when the temperature of the multi-zone crystal growth furnace reaches 150℃, 1 atm of inert gas is introduced into the furnace and all gas valves are closed to bring the gas pressure inside the furnace to near atmospheric pressure. Introducing inert gas at this point can protect and stabilize the reaction environment, preventing metal from entering the furnace. The source precursor evaporates in large quantities during the heating process, which would otherwise waste raw materials. This ensures the utilization rate of raw materials for subsequent single crystal growth and reduces production costs.

[0135] Then, the temperature of the source region is raised from 1000℃ to 1400℃ at a heating rate of 5℃ / min using the heating program of the multi-temperature zone crystal growth furnace. At the same time, the temperature of the growth region is raised from 1000℃ to 1300℃ at a heating rate of 5℃ / min using the heating program of the multi-temperature zone crystal growth furnace, so as to ensure that the temperature of the source region is higher than that of the growth region.

[0136] In this step, by setting the temperature of the source region higher than that of the growth region, the required temperature distribution for the reaction is provided. On the one hand, the higher temperature accelerates the evaporation rate of the metal suboxides, allowing them to be transported to the substrate surface more quickly. On the other hand, when the oxygen source gas is... At that time, ensure The metal suboxide exhibits reducing properties in the source region and oxidizing properties in the growth region, thus making it almost unaffected by the metal suboxide in the source region. The reaction occurs on the substrate surface with... A reaction occurs.

[0137] Keeping the source and growth regions at constant temperatures, a carrier gas and an oxygen source gas are introduced into the multi-temperature zone crystal growth furnace. The carrier gas carries the metal... The metal suboxide formed by the reaction of the source precursor after heating is directionally transported to the substrate surface, fully mixed with the oxygen source gas, and an oxide epitaxial film is grown on the substrate surface.

[0138] Specifically, this step also includes: first, maintaining the temperature of each zone in the multi-temperature zone crystal growth furnace constant, continuously introducing carrier gas into the internal tube and continuously introducing oxygen source gas into the interlayer, with a carrier gas to oxygen source gas flow ratio of 4:3; and continuously discharging the reacted gas through the exhaust port below the growth zone; wherein the carrier gas and the inert gas are both... The oxygen source gas is .

[0139] Specifically, the carrier gas will carry the metal The gaseous metal suboxides or solid or liquid metal suboxides with high saturated vapor pressure formed by the reaction of the source precursor after heating are directionally transported to the substrate of the growth zone. Oxygen source gas enters the substrate of the growth zone from the interlayer, and the two are uniformly mixed. At this time, the gas pressure inside the multi-temperature zone crystal growth furnace is atmospheric pressure or near-atmospheric pressure. Specifically… .

[0140] The selected samples were annealed. Specifically, the annealing temperature was 1300℃, the annealing time was 6 h, and the annealing pressure was 1.2 atm. Atmosphere.

[0141] Example 3: The method for preparing a deep ultraviolet transparent high conductivity gallium oxide electrode provided in this example is basically the same as that in Example 2, except that the heating temperature of the growth region is set to 1250℃ and no annealing treatment is performed.

[0142] Example 4: The method for preparing the deep ultraviolet transparent high conductivity gallium oxide electrode provided in this example is exactly the same as that in Example 3. It is an independent batch to verify the stability and repeatability of the process.

[0143] Example 5: The method for preparing the deep ultraviolet transparent high conductivity gallium oxide electrode provided in this example is exactly the same as that in Example 3. It is an independent batch to verify the stability and repeatability of the process.

[0144] Performance testing:

[0145] The unannealed deep ultraviolet transparent high-conductivity gallium oxide electrode prepared in Example 1 was subjected to aberration-corrected transmission electron microscopy. The test results are as follows: Figure 3 , Figure 4 As shown.

[0146] from Figure 3 As can be seen from the data, the unannealed deep ultraviolet transparent high-conductivity gallium oxide electrode prepared in Example 1 of this invention exhibits a clear interface between the grown gallium oxide and the substrate, with long-range ordered atomic arrangement. The Fast Fourier Transform (FFT) spectrum of the gallium oxide region shows a clearly visible dot matrix without stray signals. This proves that the prepared deep ultraviolet transparent high-conductivity gallium oxide electrode is a high-quality gallium oxide single crystal. Figure 3Atomic-level defects can be observed in the data. Defect-free regions and defective regions are marked with "Normal" and "Defect," respectively. By comparison, it can be seen that there is an interstitial defect in the prepared deep ultraviolet transparent high-conductivity gallium oxide electrode.

[0147] Figure 4 Further comparison was made between the defect-free region and the defective region, and intensity profiles were collected for each. The intensity profile of the defect-free region showed four intensity peaks: the two outer peaks corresponded to O atoms, and the two inner peaks corresponded to... Atoms. In the intensity profile of the defect region, there are 5 intensity peaks. The intensity of the two outer O atom peaks is almost unchanged compared to the defect-free region, while the intensity of the two inner peaks... The intensity of the atomic peak is significantly lower than that of the defect-free region. Meanwhile, a new intensity peak appears at the center of the defect-free region, with an intensity approximately equal to... The intensity of the weakening atomic peaks indicates that the interstitial atoms are... Atom, that is .

[0148] The XRD spectra of the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 1-5 above were measured respectively, and the results are as follows: Figure 5a As shown in ~e.

[0149] from Figure 5a As can be seen from ~b, in the full spectrum before and after annealing of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Examples 1-2 of the present invention, apart from the single crystal substrate diffraction peak at 41.7°, only the diffraction peaks of the (-310) and (-620) crystal planes of the epitaxial film appear in the spectrum, indicating that the deep ultraviolet transparent high conductivity gallium oxide electrode prepared has a (-310) orientation.

[0150] from Figure 5c As can be seen from ~e, in the full spectrum of the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 3 to 5 of the present invention, apart from the single crystal substrate diffraction peak at 41.7°, only the diffraction peaks of the (-310) and (-620) crystal planes of the epitaxial film appear in the spectrum, indicating that the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared have a (-310) orientation.

[0151] The XRD rocking curve spectra of the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 1-5 above were measured respectively. The results are as follows: Figure 6a As shown in ~e.

[0152] from Figure 6aAs can be seen from ~b, the crystal quality of the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 1 and 2 of this invention was improved after annealing, and the half-width at half maximum (WHM) of the rocking curve of their (-620) crystal plane was reduced. After annealing, the WHM of the rocking curve of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 1 decreased from 0.127° to 0.084°; after annealing, the WHM of the rocking curve of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 2 decreased from 0.154° to 0.143°. Annealing, Repair The defects and crystal quality of the deep ultraviolet transparent high conductivity gallium oxide electrode were improved.

[0153] from Figure 6c As can be seen from ~e, the half-width at half-maximum (WHM) of the rocking curves of the (-620) crystal plane of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Examples 3 to 5 of the present invention are 0.102°, 0.114°, and 0.111°, respectively, which proves the stability and repeatability of the process.

[0154] The transmission spectra of the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 1-5 above were measured respectively, and the results are as follows: Figure 7a As shown in ~e.

[0155] from Figure 7a As can be seen from the data, the deep ultraviolet transparent highly conductive gallium oxide electrode prepared in Example 1 had an average transmittance of over 30% for light in the wavelength range of 260 nm to 800 nm before annealing, and after annealing, the average transmittance of the deep ultraviolet transparent highly conductive gallium oxide electrode for light in the wavelength range of 260 nm to 800 nm reached over 80%. This indicates that the prepared deep ultraviolet transparent highly conductive gallium oxide electrode has high transmittance for both ultraviolet and visible light.

[0156] from Figure 7b As can be seen from the above, the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 2 had an average transmittance of more than 20% for light in the wavelength range of 260 nm to 800 nm before annealing, and an average transmittance of more than 40% for light in the wavelength range of 260 nm to 800 nm after annealing. This indicates that the prepared deep ultraviolet transparent high conductivity gallium oxide electrode has high transmittance for both ultraviolet and visible light.

[0157] from Figure 7c , Figure 7d , Figure 7eAs can be seen from the above, the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 3, 4 and 5 of the present invention have average transmittance of more than 30%, 30% and 20% for light in the wavelength range of 260 nm to 800 nm, respectively, indicating that the prepared deep ultraviolet transparent high conductivity gallium oxide electrodes have high transmittance for ultraviolet and visible light.

[0158] Test calculations were performed on the deep ultraviolet transparent highly conductive gallium oxide electrodes prepared in Examples 1-5 of this invention. and Relationship, result as Figure 8a As shown in ~e. Figure 8a The intersection of the straight line portion of the curve in ~e with the x-axis represents the approximate optical band gap of the deep ultraviolet transparent highly conductive gallium oxide electrode.

[0159] from Figure 8a As can be seen from the data, the optical band gap of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 1 reached 4.72 eV before annealing and 4.75 eV after annealing.

[0160] from Figure 8b As can be seen from the data, the optical bandgap of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 2 reached 4.62 eV before annealing and 4.65 eV after annealing.

[0161] from Figure 8c As can be seen from ~e, the optical band gaps of the deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in Examples 3 to 5 are 4.69 eV, 4.70 eV, and 4.66 eV, respectively.

[0162] The deep ultraviolet transparent high conductivity gallium oxide electrodes (unannealed) prepared in Examples 1-5 were subjected to Hall effect testing, and the results are shown in Table 1 below. The ohmic verification of the Hall effect tests in Examples 1-2 is as follows: Figure 9a As shown in ~b. Figure 9a The IV curve shown in ~b demonstrates a good linear relationship between the test voltage and current, proving that the prepared electrode has a high-quality ohmic contact.

[0163] Table 1 - Hall effect test results of deep ultraviolet transparent high conductivity gallium oxide electrodes prepared in different embodiments

[0164] Example (unannealed) Carrier type resistivity ) migration rate ) Carrier concentration ( ) Example 1 n 32.8 Example 2 n 63.3 Example 3 n 71.2 Example 4 n 74 Example 5 n 65

[0165] As shown in Table 1, the resistivity of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 1 is... The carrier mobility is The carrier concentration is This indicates that the prepared deep ultraviolet transparent highly conductive gallium oxide electrode has good conductivity; the resistivity of the deep ultraviolet transparent highly conductive gallium oxide electrode prepared in Example 2 is... The carrier mobility is The carrier concentration is This indicates that the prepared deep ultraviolet transparent high conductivity gallium oxide electrode has good conductivity; the resistivity of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 3 is... The carrier mobility is The carrier concentration is This indicates that the prepared deep ultraviolet transparent high conductivity gallium oxide electrode has good conductivity; the resistivity of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 4 is... The carrier mobility is The carrier concentration is This indicates that the prepared deep ultraviolet transparent high conductivity gallium oxide electrode has good conductivity; the resistivity of the deep ultraviolet transparent high conductivity gallium oxide electrode prepared in Example 5 is... The carrier mobility is The carrier concentration is This demonstrates that the prepared deep ultraviolet transparent high-conductivity gallium oxide electrode has good conductivity. As can be seen from the conductivity properties of Examples 1-5 above, the deep ultraviolet transparent high-conductivity gallium oxide electrode prepared by this invention has higher carrier concentration, carrier mobility, and lower resistivity, i.e., better conductivity.

[0166] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A deep ultraviolet transparent high conductive gallium oxide electrode, characterized by, include: A substrate and a highly conductive gallium oxide epitaxial film formed on the substrate; The high-conductivity gallium oxide epitaxial film has a carrier concentration higher than , a mobility higher than , and a resistivity lower than .

2. The deep ultraviolet transparent high conductive gallium oxide electrode according to claim 1, wherein The substrate includes any one of the following: a gallium oxide single crystal substrate with arbitrary crystal orientation, a heterogeneous substrate, or a heterogeneous substrate with a gallium oxide homogeneous buffer layer.

3. The deep ultraviolet transparent high conductive gallium oxide electrode according to claim 2, wherein The heterostructure substrate is any one of the following: a c-plane sapphire single crystal substrate with an oblique cut of 0°~6° along the a-axis, a (100)-plane MgO single crystal substrate, a r-plane sapphire single crystal substrate, a m-plane sapphire single crystal substrate, a-plane sapphire single crystal substrate, or a (001)-plane yttrium-stabilized zirconium oxide single crystal substrate.

4. A method for preparing the deep-ultraviolet transparent high-conductivity gallium oxide electrode according to any one of claims 1 to 3, characterized by, Includes the following steps: S1. Provide a substrate; S2, providing a metal source precursor, an oxygen source gas, and a dopant S3, a metal A high-conductivity gallium oxide epitaxial film is grown on a substrate surface using a metal source precursor, an oxygen source gas, and a dopant as raw materials.

5. The method according to claim 4, characterized in that, In step S2, the metal The source precursor is at least one of The metal Small droplets, the dopant is 、 、 at least one of its valence oxides or without using a dopant.

6. The method according to claim 5, characterized in that, The dopant and The molar ratio of the elements is (0:100) to (10:90), and the The molar ratio of the powder and the metal is 1:1 to 1:

6.

7. The method of claim 4, wherein, In step S3, the vapor phase epitaxy process is carried out in a multi-temperature zone crystal growth furnace; The multi-temperature zone crystal growth furnace includes a source region and a growth region, as well as an outer tube and an inner tube; The built-in tube is used for passing in carrier gas and loading metal A source precursor, a sandwich layer is formed between the outer wall of the built-in tube and the outer layer tube, used for passing in oxygen source gas; The built-in tube has a flow guide port on the side near the growth zone.

8. The method according to claim 7, characterized in that, Step S3 specifically includes: S31. Place the substrate in the growth region and apply the metal. A mixture of source precursor and dopant is placed in the source region; S32. After evacuation, fill with inert gas to near atmospheric pressure; S33. Heat the growth zone to 900~1400℃ and the source zone to 1100~1500℃; S34. Introduce carrier gas and oxygen source gas to transport gaseous gallium suboxide and gaseous dopant to the substrate surface to grow a highly conductive gallium oxide epitaxial film.

9. The method according to claim 8, characterized in that, Both the carrier gas and the inert gas are or At least one of the following, wherein the oxygen source gas is .

10. The method according to claim 8, characterized in that, During the growth process, the flow ratio of carrier gas to oxygen source gas is 4:1 to 4:5, and the gas pressure inside the multi-temperature zone crystal growth furnace is controlled at... .

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