CN115101633A - InGaN-based optoelectronic device and preparation method thereof - Google Patents

Abstract

The invention relates to an InGaN-based optoelectronic device and a preparation method thereof. The preparation method of the InGaN-based optoelectronic device comprises the following steps: forming an AlN transition layer on the crystal substrate, wherein the AlN transition layer consists of a plurality of first three-dimensional growth islands; epitaxially growing a GaN transition layer on the AlN transition layer, wherein the GaN transition layer consists of a plurality of second three-dimensional growth small islands, and the second three-dimensional growth small islands in the GaN transition layer are the continuation of the first three-dimensional growth small islands in the AlN transition layer to obtain a composite substrate of the InGaN-based optoelectronic device; epitaxially growing a nitride conversion layer on a composite substrate of the InGaN-based optoelectronic device in a two-dimensional epitaxial mode; and forming other device structure layers of the InGaN-based optoelectronic device on the nitride conversion layer to obtain the InGaN-based optoelectronic device. The preparation method can improve the incorporation efficiency of the In component In the InGaN-based optoelectronic device. In addition, the invention also relates to an InGaN-based optoelectronic device prepared by the preparation method of the InGaN-based optoelectronic device.

Description

InGaN-based optoelectronic device and preparation method thereof

technical field

The invention relates to the technical field of optoelectronic devices, in particular to an InGaN-based optoelectronic device and a preparation method thereof.

Background technique

The wavelength range corresponding to InGaN materials extends from the infrared band to the ultraviolet band and is continuously adjustable. At the same time, InGaN materials have the advantages of direct band gap, high electron mobility, good mechanical and chemical stability, excellent radiation resistance and temperature characteristics. The field of optoelectronics has received extensive attention. In recent years, InGaN materials have achieved great success in the fields of solid-state lighting, ultraviolet sterilization, visible light communication and LED display. However, in InGaN-based optoelectronic devices, with the gradual increase of In composition, the crystal quality of InGaN material decreases sharply, and the application of InGaN material with high In composition is greatly restricted.

The preparation of high-quality and high-In composition InGaN materials is still very difficult. The main reasons are: 1. There is a lack of lattice-matched substrates. At present, InGaN materials are mainly prepared by epitaxy on GaN substrates or templates. The epitaxial layers and substrates The lattice mismatch between them will not only generate a large number of misfit dislocations, but also introduce huge compressive stress during the epitaxy process of InGaN thin films and quantum structures. Second, with the increase of In composition, the growth temperature of InGaN materials It gradually decreases, resulting in insufficient ammonia cracking efficiency and insufficient migration distance of atoms on the surface of the substrate, making the epitaxial crystal quality of the high In composition InGaN material worse.

The key to improving the epitaxial crystal quality of InGaN thin films and quantum structures in InGaN-based optoelectronic devices is to improve the incorporation efficiency of In atoms, which in turn increases the epitaxial growth temperature of InGaN materials. Theoretical calculations show that the incorporation efficiency of In atoms is highest when the GaN substrate or template is in a weak tensile stress state. Various schemes have been proposed internationally to release the compressive stress in GaN heteroepitaxial films, such as two-dimensional material transition layers, porous GaN templates, InGaNOS templates, etc. The experimental results also prove that by releasing the compressive stress in GaN films, The crystal quality of the high In composition InGaN material is significantly improved. However, these methods are complex, expensive, and not fully compatible with the existing InGaN material preparation methods, so they are still in the laboratory research and development stage, and there is still a distance from practical application.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide an InGaN-based optoelectronic device and a preparation method for the technical problem of how to improve the incorporation efficiency of the In component in the InGaN-based optoelectronic device.

A preparation method of an InGaN-based optoelectronic device, comprising the following steps:

A physical vapor deposition method is used to form an AlN transition layer on the crystal substrate, and the AlN transition layer is composed of several first three-dimensional growth islands;

A GaN transition layer is epitaxially grown on the AlN transition layer, the GaN transition layer consists of several second three-dimensional growth islands, and the several second three-dimensional growth islands in the GaN transition layer are in the AlN transition layer The continuation of several first three-dimensional growth islands obtained by the composite substrate of InGaN-based optoelectronic devices;

A nitride conversion layer is epitaxially grown in a two-dimensional epitaxial mode on the composite substrate of the InGaN-based optoelectronic device, so that the grain boundaries of the second three-dimensional grown islands in the GaN transition layer merge, and the nitride conversion layer is Tensile stress induced by grain boundary mergers is provided in the layer; and

Other device structure layers of the InGaN-based optoelectronic device are formed on the nitride conversion layer to obtain an InGaN-based optoelectronic device.

The preparation method of the above-mentioned InGaN-based optoelectronic device has a simple process. During the preparation process, the AlN transition layer and the GaN transition layer form a composite transition layer, which can modulate the stress state in the nitride conversion layer and improve the InGaN-based optoelectronic device. In the process of InGaN material epitaxy Incorporation efficiency of atoms, thereby improving the epitaxial crystal quality of InGaN thin films and quantum structures. The preparation method of the InGaN-based optoelectronic device of the present invention has high compatibility with the epitaxial process of the existing commercial InGaN-based optoelectronic device, and the preparation method of the InGaN-based optoelectronic device of the present invention is easy to be directly applied to large-scale industrial production.

In a feasible implementation manner, the operation of forming an AlN transition layer on the crystal substrate by physical vapor deposition is as follows: using a target material with a purity of ≥99.99%, in a mixed atmosphere of argon and nitrogen, sputtering on the crystal substrate The AlN transition layer is formed by sputtering; wherein, the working pressure is 0.1Pa～1Pa, the volume fraction of nitrogen in the mixed atmosphere is 10%～90%, the temperature of the crystal substrate is 20℃～800℃, and the sputtering power is 1000W ~5000W.

In a feasible implementation manner, in the operation of epitaxially growing the GaN transition layer on the AlN transition layer, the growth temperature is 500°C to 600°C.

In a feasible implementation manner, in the operation of epitaxially growing the nitride conversion layer in the two-dimensional epitaxial mode on the composite substrate of the InGaN-based optoelectronic device, the growth temperature is 600°C to 1200°C.

In a feasible implementation manner, the thickness of the AlN transition layer ranges from 0.5 nm to 500 nm.

In a feasible implementation manner, the thickness of the GaN transition layer is 0.5 nm to 500 nm.

In a feasible implementation manner, the crystal substrate is selected from at least one of a sapphire substrate, a gallium nitride substrate, an aluminum nitride substrate, a silicon substrate, a silicon carbide substrate, and a gallium oxide substrate.

In a feasible implementation manner, the nitride conversion layer is a GaN layer, an AlN layer, an AlGaN layer or an InGaN layer; and/or the thickness of the nitride conversion layer is 0.1 μm˜10 μm.

An InGaN-based optoelectronic device is prepared by using any of the above-mentioned preparation methods for an InGaN-based optoelectronic device.

In the InGaN-based optoelectronic device of the present invention, the incorporation efficiency of In atoms during the epitaxial process of the InGaN material is high, thereby improving the epitaxial crystal quality of the InGaN thin film and the quantum structure, so that the overall efficiency of the InGaN-based optoelectronic device is high.

In a feasible implementation manner, the InGaN-based optoelectronic device is an InGaN-based LED, an InGaN-based solar cell, or an InGaN-based laser.

Description of drawings

1 is a flow chart of a method for preparing an InGaN-based optoelectronic device according to an embodiment of the present invention;

2 is a schematic diagram of a composite substrate of an InGaN-based optoelectronic device according to an embodiment of the present invention;

3 is a schematic diagram of a template of an InGaN-based optoelectronic device according to an embodiment of the present invention;

4 is a schematic diagram of an InGaN-based optoelectronic device according to an embodiment of the present invention;

5 is a schematic diagram of the InGaN-based optoelectronic device of Comparative Example 1;

6 is a schematic diagram of the InGaN-based optoelectronic device of Comparative Example 2;

7 is an atomic force microscope image of the surface of the GaN transition layer of the InGaN-based optoelectronic device of Example 1;

8 is an atomic force microscope image of the surface of the AlN transition layer of the InGaN-based optoelectronic device of Comparative Example 1;

9 is an atomic force microscope image of the surface of the GaN transition layer of the InGaN-based optoelectronic device of Comparative Example 2;

10 is the reflectivity recorded during the epitaxial growth in steps 5) to 6) in Example 1, and steps 4) to 5) in Comparative Example 1 and Comparative Example 2;

11 is the in-situ monitoring curve of warpage recorded in the epitaxial growth process in steps 5) to 6) in Example 1, and steps 4) to 5) in Comparative Example 1 and Comparative Example 2;

12 is an electroluminescence spectrum of the InGaN-based optoelectronic devices of Example 1 and Comparative Example 1. FIG.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to FIG. 1, a method for preparing an InGaN-based optoelectronic device according to an embodiment of the present invention includes the following steps:

S1. A physical vapor deposition method is used to form an AlN transition layer on the crystal substrate, and the AlN transition layer is composed of several first three-dimensional growth islands.

Please refer to FIG. 2 together. In step S1, the crystal substrate 110 refers to that the material of the substrate is crystal, and the crystal substrate 110 is used to support other layers located on the upper layer.

In one possible implementation manner, the crystal substrate 110 is selected from at least one of a sapphire substrate, a gallium nitride substrate, an aluminum nitride substrate, a silicon substrate, a silicon carbide substrate, and a gallium oxide substrate. That is to say, the crystal substrate 110 may be a single-layer sapphire substrate, a gallium nitride substrate, an aluminum nitride substrate, a silicon substrate, a silicon carbide substrate or a gallium oxide substrate, or may be stacked from the same or different substrates mentioned above. composed of multilayer substrates.

In step S1, the AlN transition layer 120 formed on the crystal substrate 110 by the physical vapor deposition method is composed of a large number of dense crystal grains (ie, the first three-dimensional growth islands), and the c-axis orientation of the crystal grains is highly consistent. The AlN transition layer 120 provides an initial growth state and increases the uniformity of grain orientation in a certain direction. In addition, the AlN transition layer 120 can also prevent Ga from corroding the crystal substrate 110 during the subsequent growth of GaN. The process parameters and deposition time of the film deposition can be adjusted to achieve the control of the thickness, surface morphology and crystal quality of the AlN transition layer. The AlN transition layer can also be annealed at high temperature to improve its crystalline quality.

In one of the possible implementations, the operation of forming the AlN transition layer 120 on the crystal substrate 110 by using the physical vapor deposition method is as follows: using a target material with a purity of ≥99.99%, in a mixed atmosphere of argon and nitrogen, in the crystal The AlN transition layer is formed by sputtering on the substrate; wherein, the working pressure is 0.1Pa～1Pa, the volume fraction of nitrogen in the mixed atmosphere is 10%～90%, the temperature of the crystal substrate is 20℃～800℃, and the sputtering power is 1000W～ 5000W. Among them, high-purity aluminum can be selected as the target material; argon in the mixed atmosphere is a sputtering gas, which can be high-purity argon, and nitrogen is a reactive gas, which can be high-purity nitrogen. Specifically, high-purity argon is used as a sputtering gas to discharge to form ions, which are accelerated by an electric field and bombard high-purity aluminum as a sputtering target, so that the aluminum atoms of the target are sputtered out and the high-purity nitrogen as a reactive gas forms aluminum nitride. deposited on the surface of a heated crystalline substrate.

In one possible implementation manner, the thickness of the AlN transition layer 120 is 0.5 nm˜500 nm. For example, the thickness of the AlN transition layer 120 may be 0.5 nm, 1 nm, 5 nm, 10 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, or 500 nm.

S2. The GaN transition layer is epitaxially grown on the AlN transition layer. The GaN transition layer is composed of several second three-dimensional growth islands, and several second three-dimensional growth islands in the GaN transition layer are several first three-dimensional growths in the AlN transition layer The continuation of the island leads to the composite substrate of the InGaN-based optoelectronic device.

Please refer to FIG. 2 together. In step S2, the heteroepitaxial substrate plated with the AlN transition layer 120 can be loaded on the heating base of the epitaxial equipment. Under appropriate temperature and other process parameters, the AlN transition layer 120 The GaN transition layer 130 is prepared by top epitaxy. By controlling the process conditions and growth time of the GaN transition layer 130 , the size and grain boundary density of the second three-dimensional growth islands in the GaN transition layer 130 can be controlled.

Wherein, the epitaxy equipment may be metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE) or other forms of epitaxy equipment. The process conditions include parameters such as temperature, chamber pressure, V/III ratio, rotational speed of the substrate base, flow rate of the reaction source, and the like.

In one possible implementation manner, in the operation of epitaxially growing the GaN transition layer 130 on the AlN transition layer 120 , the growth temperature is 500° C.˜600° C. At this time, the formation of the second three-dimensional growth islands and grain boundaries in the GaN transition layer 130 can be promoted.

In one possible implementation manner, the thickness of the GaN transition layer 130 is 0.5 nm˜500 nm. For example, the thickness of the GaN transition layer 130 may be 0.5 nm, 1 nm, 5 nm, 10 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, or 500 nm.

After step S2, the composite substrate 100 of the InGaN-based optoelectronic device as shown in FIG. 2 can be obtained.

S3. The nitride conversion layer is epitaxially grown in a two-dimensional epitaxial mode on the composite substrate of the InGaN-based optoelectronic device, so that the grain boundaries of the second three-dimensional growth islands in the GaN transition layer merge and provide crystallinity in the nitride conversion layer. bound and induced tensile stress.

Please refer to FIG. 3 together. In step S3, in the process of epitaxially growing the nitride conversion layer 210 on the composite substrate 100 of the InGaN-based optoelectronic device in a two-dimensional epitaxial mode, the AlN transition layer 120 can be grown from several first three-dimensional layers. The grain boundaries of the islets and the second three-dimensionally grown islets in the GaN transition layer 130 merge rapidly. At the same time, a grain boundary and induced tensile stress is provided in the continuous epitaxial thin film (ie, the nitride conversion layer), enabling modulation of the stress state in the nitride heteroepitaxial thin film.

In one possible implementation manner, in the operation of epitaxially growing the nitride conversion layer 210 , the growth temperature is 600° C.˜1200° C. In this step, the stress state in the continuous nitride conversion layer 210 can be monitored in real time by monitoring the warpage of the composite substrate 100 of the InGaN-based optoelectronic device in situ.

In one possible implementation manner, the thickness of the nitride conversion layer 210 is 0.1 μm˜10 μm.

After step S3, the template 200 of the InGaN-based optoelectronic device as shown in FIG. 3 can be obtained. The template 200 of the InGaN-based optoelectronic device sequentially includes the composite substrate 100 of the InGaN-based optoelectronic device and the nitride conversion layer 210 from bottom to top. The composite substrate 100 of the InGaN-based optoelectronic device includes a crystal substrate 110 , an AlN transition layer 120 and a GaN transition layer 130 in order from bottom to top.

S4, forming other device structure layers of the InGaN-based optoelectronic device on the nitride conversion layer to obtain an InGaN-based optoelectronic device.

In step S4, other device structure layers may be formed on the nitride conversion layer by using a process commonly used in the art, and other device structure layers may be selected according to specific InGaN-based optoelectronic devices.

Please refer to FIG. 4 together. In one feasible implementation manner, the InGaN-based optoelectronic device 300 is an InGaN-based red LED, and other device structure layers of the InGaN-based optoelectronic device include an n-type GaN layer 310, an InGaN/GaN multiple quantum well layer 320 and p-type GaN layer 330 .

The preparation method of the above-mentioned InGaN-based optoelectronic device has a simple process. During the preparation process, the AlN transition layer and the GaN transition layer form a composite transition layer, which can modulate the stress state in the nitride conversion layer and improve the InGaN-based optoelectronic device. In the process of InGaN material epitaxy Incorporation efficiency of atoms, thereby improving the epitaxial crystal quality of InGaN thin films and quantum structures. The preparation method of the InGaN-based optoelectronic device of the present invention has high compatibility with the epitaxial process of the existing commercial InGaN-based optoelectronic device, and the preparation method of the InGaN-based optoelectronic device of the present invention is easy to be directly applied to large-scale industrial production.

Referring to FIG. 4 , an InGaN-based optoelectronic device 300 according to an embodiment of the present invention is prepared by using any of the above-mentioned preparation methods for an InGaN-based optoelectronic device.

In one of the possible implementations, the InGaN-based optoelectronic device 300 is an InGaN-based red LED, which sequentially includes the template 200 of the InGaN-based optoelectronic device, the n-type GaN layer 310 , the InGaN/GaN multiple quantum well layer 320 and the p- type GaN layer 330 . Wherein, the template 200 of the InGaN-based optoelectronic device sequentially includes the composite substrate 100 of the InGaN-based optoelectronic device and the nitride conversion layer 210 from bottom to top. The composite substrate 100 of the InGaN-based optoelectronic device includes a crystal substrate 110 , an AlN transition layer 120 and a GaN transition layer 130 in order from bottom to top.

Of course, the InGaN-based optoelectronic device of the present invention is not limited to the above-mentioned InGaN-based LED, but can also be an InGaN-based solar cell or an InGaN-based laser.

Further, the InGaN-based optoelectronic device 300 of the present invention includes a high-In composition InGaN film and a quantum structure and related auxiliary structures, wherein the high-In composition InGaN film and quantum structure and related auxiliary structures can be a current injection layer and a long-wavelength InGaN-based structure. Active region structures of optoelectronic devices such as LEDs, InGaN-based solar cells, and long-wavelength InGaN-based lasers, or other forms of accessory structures.

In the InGaN-based optoelectronic device of the present invention, the incorporation efficiency of In atoms during the epitaxial process of the InGaN material is high, thereby improving the epitaxial crystal quality of the InGaN thin film and the quantum structure, so that the overall efficiency of the InGaN-based optoelectronic device is high.

Referring to the above implementation content, in order to make the technical solution of the present application more specific, clear and easy to understand, the technical solution of the present application is now given as an example, but it should be noted that the content to be protected by the present application is not limited to the following embodiment 1.

Example 1

Referring to FIG. 4 , the InGaN-based optoelectronic device 300 of Embodiment 1 is an InGaN-based red light emitting diode, which includes, from bottom to top, a template 200 of the InGaN-based optoelectronic device, an n-type GaN layer 310 , an InGaN/GaN multiple quantum well layer 320 and p-type GaN layer 330 . The template 200 of the InGaN-based optoelectronic device sequentially includes the composite substrate 100 of the InGaN-based optoelectronic device and the nitride conversion layer 210 from bottom to top, wherein the nitride conversion layer 210 is made of GaN. The composite substrate 100 of the InGaN-based optoelectronic device sequentially includes a crystal substrate 110 , an AlN transition layer 120 and a GaN transition layer 130 from bottom to top, wherein the crystal substrate 110 is made of c-plane sapphire.

The preparation method of the InGaN-based red light-emitting diode of Embodiment 1 includes the following steps:

1) High-purity argon gas is used as sputtering gas to discharge to form ions, which are accelerated by electric field and bombard high-purity aluminum (purity ≥99.99%) as sputtering target, so that the aluminum atoms of the target are sputtered out and the high-purity reaction gas Nitrogen gas forms aluminum nitride and is deposited on the heated crystal substrate 110 to obtain an AlN transition layer 120 with a thickness of 25 nm. The working pressure in the above process is 0.67 Pa, the volume fraction of nitrogen is 25%, and the temperature of the crystal substrate 110 is 550° C. , the sputtering power is 3000W. The formed AlN transition layer 120 is composed of a large number of dense first three-dimensional growth islands, and the c-axis orientation of the first three-dimensional growth islands has a high degree of uniformity.

2) After ultrasonically cleaning the crystal substrate 110 coated with the AlN transition layer 120 in acetone, alcohol and deionized water for 10 minutes each, dry the surface with dry nitrogen.

3) Load the dried crystal substrate 110 coated with the AlN transition layer 120 on the heating base of the MOCVD equipment, and after the temperature is raised to 1080° C., perform a high-temperature surface thermal cleaning process in a hydrogen atmosphere for 10 minutes.

4) Cool the heating base to 550°C, pass trimethylgallium and ammonia gas into the reaction chamber, and prepare a GaN transition layer 130 composed of second three-dimensional growth islands on the AlN transition layer 120 to obtain an InGaN base Composite substrate 100 for optoelectronic devices. In this embodiment, the thickness of the GaN transition layer 130 is 5 nm.

5) Raise the temperature of the heating susceptor to 1075°C, set the MOCVD chamber pressure to 200 torr, the V/III ratio to 2500 and the heating susceptor rotational speed to 1200 rpm, and perform epitaxy on the GaN/AlN composite transition layer in two-dimensional epitaxy mode The continuous nitride conversion layer 210 is prepared so that the grain boundaries in the GaN transition layer 130 are rapidly merged, and tensile stress induced by the grain boundary merger is provided in the nitride conversion layer 210 to obtain a template 200 for an InGaN-based optoelectronic device. In this embodiment, the thickness of the nitride conversion layer 210 is 2 μm.

6) On the basis of step 5), set the temperature of the heating susceptor to 1060° C., the MOCVD chamber pressure to 200 torr, the V/III ratio to 2500 and the rotational speed of the heating susceptor to 1200 rpm, and to epitaxially grow the n-type GaN layer 310 as The current injection layer of the first conductivity type of the InGaN-based red light emitting diode. In this embodiment, the thickness of the n-type GaN layer 310 is 2 μm.

7) On the basis of step 6), the MOCVD chamber pressure is set to 200torr, the V/III ratio is 4000, and the rotation speed of the heating base is 1200rpm, and an InGaN/GaN multiple quantum well layer 320 is epitaxially grown in a nitrogen carrier gas atmosphere as In the light-emitting active region of the InGaN red LED, the growth temperature of the InGaN well layer is 700°C, and the growth temperature of the GaN barrier layer is 800°C; the temperature of the heating base is set to 950°C, and the MOCVD cavity pressure is 200torr, The V/III ratio was 2500 and the rotation speed of the heating base was 1200 rpm. The p-type GaN layer 330 was epitaxially prepared as the current injection layer of the second conductivity type of the InGaN-based red light emitting diode, and the InGaN-based optoelectronic device 300 of Example 1 was obtained.

Comparative Example 1

Referring to FIG. 5 , the InGaN-based optoelectronic device 100 ′ of Comparative Example 1 is an InGaN-based red light-emitting diode, which sequentially includes a sapphire substrate 110 ′, an AlN transition layer 120 ′, a GaN conversion layer 130 ′, and an n-type GaN layer from bottom to top 140', an InGaN/GaN multiple quantum well layer 150' and a p-type GaN layer 160', wherein the material of the sapphire substrate 110' is c-plane sapphire.

The preparation method of the InGaN-based red light-emitting diode of Comparative Example 1 includes the following steps:

1) High-purity argon gas is used as sputtering gas to discharge to form ions, which are accelerated by electric field and bombard high-purity aluminum (purity ≥99.99%) as sputtering target, so that the aluminum atoms of the target are sputtered out and the high-purity reaction gas Nitrogen gas forms aluminum nitride and is deposited on the heated sapphire substrate 110' to obtain an AlN transition layer 120' with a thickness of 25 nm. The working pressure in the above process is 0.67 Pa, the volume fraction of nitrogen is 25%, and the temperature of the sapphire substrate 110' is is 550°C, and the sputtering power is 3000W. The formed AlN transition layer 120' is composed of a large number of dense first three-dimensional growth islands, and the c-axis orientation of the first three-dimensional growth islands has a high degree of uniformity.

2) After ultrasonically cleaning the sapphire substrate 110' coated with the AlN transition layer 120' in acetone, alcohol and deionized water for 10 minutes each, dry the surface with dry nitrogen.

3) The dried sapphire substrate 110' coated with the AlN transition layer 120' is loaded on the heating base of the MOCVD equipment, and after the temperature is raised to 1080°C, a high-temperature surface thermal cleaning process is performed in a hydrogen atmosphere for 10 minutes.

4) Adjust the temperature of the heating susceptor to 1075°C, set the MOCVD chamber pressure to 200 torr, the V/III ratio to 2500 and the heating susceptor speed to 1200 rpm, and epitaxially prepare continuous GaN on the AlN transition layer in two-dimensional epitaxy mode conversion layer 130'. In this comparative example, the thickness of the GaN conversion layer 130' is 2 µm.

5) On the basis of step 4), set the temperature of the heating susceptor to 1060°C, the MOCVD chamber pressure to 200 torr, the V/III ratio to 2500 and the rotational speed of the heating susceptor to 1200 rpm, and the n-type GaN layer 140' as the InGaN base. The current injection layer of the first conductivity type of the red light emitting diode. In this comparative example, the thickness of the n-type GaN layer was 2 μm.

6) On the basis of step 5), the MOCVD chamber pressure is set to 200torr, the V/III ratio is 4000, and the rotation speed of the heating base is 1200rpm, and the InGaN/GaN multiple quantum well layer 150' is epitaxially grown in a nitrogen carrier gas atmosphere. As the light-emitting active region of the InGaN red LED, the growth temperature of the InGaN well layer is 700°C, and the growth temperature of the GaN barrier layer is 800°C; the temperature of the heating base is set to 950°C, and the pressure of the MOCVD cavity is 200torr , V/III ratio is 2500 and the rotation speed of the heating base is 1200rpm, the p-type GaN layer 160' is epitaxially prepared as the current injection layer of the second conductivity type of the InGaN-based red light emitting diode, and the InGaN-based optoelectronic device of Comparative Example 1 is obtained. 100'.

Comparative Example 2

Referring to FIG. 6 , the InGaN-based optoelectronic device 200 ′ of Comparative Example 2 is an InGaN-based red light-emitting diode, which includes a sapphire substrate 210 ′, a GaN transition layer 220 ′, a GaN conversion layer 230 ′, and an n-type GaN layer in order from bottom to top 240', the InGaN/GaN multiple quantum well layer 250' and the p-type GaN layer 260', wherein the material of the sapphire substrate 210' is c-plane sapphire.

The preparation method of the InGaN-based red light-emitting diode of Comparative Example 2 includes the following steps:

1) After ultrasonically cleaning the sapphire substrate 210' in acetone, alcohol and deionized water for 10 minutes each, dry the lining surface with dry nitrogen.

2) The dry sapphire substrate 210' is loaded on the heating base of the MOCVD equipment, and after the temperature is raised to 1080°C, a high-temperature surface thermal cleaning process is performed in a hydrogen atmosphere for 10 minutes.

3) The heating base is cooled to 550° C., and trimethylgallium and ammonia gas are introduced into the reaction chamber. As shown in FIG. 2 , a GaN transition layer 220 consisting of three-dimensionally grown islands is prepared on the sapphire substrate 210 ′. '. In this comparative example, the thickness of the GaN transition layer 220' is 5 nm.

4) Raise the temperature of the heating susceptor to 1075°C, set the MOCVD chamber pressure to 200 torr, the V/III ratio to 2500 and the rotational speed of the heating susceptor to 1200 rpm, and epitaxially prepare the GaN transition layer 220' in a two-dimensional epitaxy mode Continuous GaN conversion layer 230'. In this comparative example, the thickness of the GaN conversion layer 230' is 2 µm.

5) On the basis of step 4), the temperature of the heating base is set to 1060°C, the pressure of the MOCVD chamber is 200torr, the V/III ratio is 2500 and the rotation speed of the heating base is 1200rpm, and the n-type GaN layer 240' is epitaxially grown. As the current injection layer of the first conductivity type of the InGaN-based red light emitting diode. In this comparative example, the thickness of the n-type GaN layer 240' is 2 µm.

6) On the basis of step 5), the MOCVD chamber pressure is set to 200torr, the V/III ratio is 4000, and the rotation speed of the heating base is 1200rpm, and the InGaN/GaN multiple quantum well layer 250' is epitaxially grown in a nitrogen carrier gas atmosphere. As the light-emitting active region of the InGaN red LED, the growth temperature of the InGaN well layer is 700°C, and the growth temperature of the GaN barrier layer is 800°C; the temperature of the heating base is set to 950°C, and the pressure of the MOCVD cavity is 200torr , V/III ratio is 2500 and the rotation speed of the heating base is 1200rpm, the p-type GaN layer 260' is epitaxially prepared as the current injection layer of the second conductivity type of the InGaN-based red light-emitting diode, and the InGaN-based optoelectronic device of Comparative Example 2 is obtained. 200'.

Performance Testing:

The surface of the GaN transition layer of the InGaN-based optoelectronic device of Example 1, the surface of the AlN transition layer of the InGaN-based optoelectronic device of Comparative Example 1, and the surface of the GaN transition layer of the InGaN-based optoelectronic device of Comparative Example 2 were respectively scanned by atomic force microscopy, and the graphs were obtained. 7 to Figure 9. It can be seen from Figures 7 to 9 that the transition layers of different structures have different surface topographic characteristics. The GaN transition layer of the InGaN-based optoelectronic device of Example 1 is composed of second-dimensional growth islands with larger sizes, and the three-dimensional small islets. The islands are connected to each other and there are voids, while the AlN transition layer of the InGaN-based optoelectronic device of Comparative Example 1 is composed of small three-dimensional growth islands to form a dense quasi-continuous film, and the GaN transition layer of the InGaN-based optoelectronic device of Comparative Example 2 It consists of three-dimensional growth islands of smaller size and lower density.

In-situ monitoring of reflectivity and warpage during the epitaxial growth process of steps 5) to 6) in Example 1 and steps 4) to 5) in Comparative Example 1 and Comparative Example 2 was performed, and FIGS. 10 and 11 were obtained. It can be seen from FIG. 10 and FIG. 11 that for the case of using the GaN transition layer in Comparative Example 2, the continuous GaN thin film described in steps 4 to 5) in Comparative Example 2 cannot be prepared in two-dimensional epitaxy mode. According to the in-situ monitoring curves of warpage of Example 1 and Comparative Example 1, it can be deduced that the tensile stress in the n-type GaN layer of Example 1 and the n-type GaN layer of Comparative Example 1 are 1.72GPa and 1.51GPa, respectively.

The electroluminescence spectra of the InGaN-based optoelectronic devices of Example 1 and Comparative Example 1 are shown in FIG. 12 . It can be seen from FIG. 12 that the LED epitaxial structure of the InGaN-based optoelectronic device prepared in Example 1 using the GaN/AlN composite transition layer has a longer emission wavelength, that is, a higher incorporation efficiency of the In composition.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. A preparation method of an InGaN-based optoelectronic device is characterized by comprising the following steps:

forming an AlN transition layer on the crystal substrate by adopting a physical vapor deposition method, wherein the AlN transition layer consists of a plurality of first three-dimensional growth islands;

epitaxially growing a GaN transition layer on the AlN transition layer, wherein the GaN transition layer consists of a plurality of second three-dimensional growth small islands, and the plurality of second three-dimensional growth small islands in the GaN transition layer are the continuations of the plurality of first three-dimensional growth small islands in the AlN transition layer, so as to obtain a composite substrate of the InGaN-based optoelectronic device;

epitaxially growing a nitride conversion layer on the composite substrate of the InGaN-based optoelectronic device in a two-dimensional epitaxial mode, so that grain boundaries of the second three-dimensional growth island in the GaN transition layer are merged, and providing tensile stress formed by grain boundary merging induction in the nitride conversion layer; and

and forming other device structure layers of the InGaN-based optoelectronic device on the nitride conversion layer to obtain the InGaN-based optoelectronic device.

2. The method of fabricating an InGaN-based optoelectronic device as set forth in claim 1, wherein the forming of the AlN transition layer on the crystal substrate by physical vapor deposition is performed by: sputtering a target material with the purity of more than or equal to 99.99 percent on a crystal substrate to form an AlN transition layer in the mixed atmosphere of argon and nitrogen; wherein the working pressure is 0.1 Pa-1 Pa, the volume fraction of nitrogen in the mixed atmosphere is 10% -90%, the temperature of the crystal substrate is 20-800 ℃, and the sputtering power is 1000-5000W.

3. The method for manufacturing an InGaN-based optoelectronic device according to claim 1, wherein the growth temperature in the operation of epitaxially growing the GaN transition layer on the AlN transition layer is 500 to 600 ℃.

4. The method of manufacturing an InGaN-based optoelectronic device according to claim 1, wherein the growth temperature in the operation of epitaxially growing the nitride epitaxial layer in the two-dimensional epitaxial mode on the composite substrate of the InGaN-based optoelectronic device is 600 to 1200 ℃.

5. The method of fabricating an InGaN-based optoelectronic device of claim 1, wherein the AlN transition layer has a thickness of 0.5nm to 500 nm.

6. The method of claim 1, wherein the GaN transition layer has a thickness of 0.5nm to 500 nm.

7. The method of manufacturing an InGaN-based optoelectronic device of claim 1, wherein the crystal substrate is at least one selected from a sapphire substrate, a gallium nitride substrate, an aluminum nitride substrate, a silicon carbide substrate, and a gallium oxide substrate.

8. The method of manufacturing an InGaN-based optoelectronic device according to claim 1, wherein the nitride epitaxial layer is a GaN layer, an AlN layer, an AlGaN layer, or an InGaN layer; and/or the thickness of the nitride epitaxial layer is 0.1-10 μm.

9. An InGaN-based optoelectronic device, characterized in that the InGaN-based optoelectronic device is prepared by the method of any one of claims 1 to 8.

10. InGaN-based optoelectronic device according to claim 9, wherein the InGaN-based optoelectronic device is an InGaN-based LED, an InGaN-based solar cell or an InGaN-based laser.

Images