LED epitaxial wafer structure with high luminous efficiency

Abstract

A high luminous efficiency LED epitaxial wafer structure belongs to the technical field of light emitting diodes, and comprises a substrate, and a buffer layer, an unintentional doping layer, an N-GaN layer, a first well layer, a second well layer, a built-in EBL layer, a quantum well light emitting layer, a P-type electron blocking layer and a P-GaN layer which are sequentially deposited on the substrate, the unintentional doping layer is a U-type GaN layer, the built-in EBL layer is an ALGaN layer, and the P-GaN layer is a P-type GaN layer; the temperature of the first well layer and the second well layer is increased in the epitaxial process, H2 is introduced into the first well layer and the H2 introduction amount of the first well layer is greater than that of the second well layer, so that the epitaxial quality of the quantum barrier is improved, and the dislocation defect is reduced; the built-in EBL layer is arranged, the built-in EBL layer is an ALGaN layer, electrons can be effectively blocked by utilizing the characteristic that the forbidden band width of AlGaN is large, and the electron utilization rate can be further improved; the interface processing layer is arranged, bottom layer derivation dislocation is eliminated through pause discontinuous barrier crystal annihilation, the lattice quality is improved, the composite luminous efficiency is improved, and finally the luminous efficiency of the product is greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of light emitting diodes, and in particular relates to a high-light-efficiency LED epitaxial wafer structure. Background Art

[0002] Light Emitting Diode (LED) is a semiconductor electronic component that can emit light. As an efficient, energy-saving and environmentally friendly solid-state lighting source, LED is widely used in fields such as traffic lights, automobile interior and exterior lights, urban landscape lighting, daily lighting and display screens.

[0003] How to improve the quality and luminous efficiency of LED epitaxy has always been a pain point and difficulty in the semiconductor industry. The existing structure has low quantum well IN atom doping temperature and obvious penetration, resulting in unsatisfactory final epitaxy quality. In addition, the electron blocking layer in the existing technology usually prevents electrons from overflowing quickly by doping Al, but Al and GaN lattice are highly compatible, the lattice quality will deteriorate and affect the luminous efficiency. Utility Model Content

[0004] In order to solve the defects existing in the background, the utility model provides a high-light-efficiency LED epitaxial wafer structure, which can improve the lattice quality, increase the electron utilization rate, and ultimately improve the composite luminous efficiency.

[0005] To achieve the above purpose, the technical solution of the utility model is as follows:

[0006] A high-light-efficiency LED epitaxial wafer structure, characterized by comprising a substrate, a buffer layer, an unintentionally doped layer, an N-GaN layer, a well layer 1, a well layer 2, an interface treatment layer, a built-in EBL layer, a quantum well light-emitting layer, a P-type electron blocking layer, and a P-GaN layer sequentially deposited on the substrate;

[0007] Among them, the unintentionally doped layer is a U-type GaN layer, the N-GaN layer is an N-type GaN layer, the well layer 1 and the well layer 2 are GaN barrier layers, the thickness range of the well layer 1 is 0.3-0.4nm, the thickness range of the well layer 2 is 0.2-0.3nm, the interface treatment layer is located between the well layer 2 and the built-in EBL layer, the built-in EBL layer is an ALGaN layer, the thickness range of the built-in EBL layer is 1-5nm, and the P-GaN layer is a P-type GaN layer.

[0008] Preferably, the substrate is a sapphire substrate, and the buffer layer is a GaN buffer layer.

[0009] Preferably, the thickness of the first well layer is 0.3 nm, and the thickness of the second well layer is 0.2 nm.

[0010] Preferably, the interface treatment layer is generated by introducing H2 between the second well layer and the built-in EBL layer, the duration of introducing H2 is 10-60 seconds, and the reaction temperature ranges from 750-900°C.

[0011] Preferably, the thickness of the built-in EBL layer is 1 nm.

[0012] Preferably, H2 is introduced into the well layer 1 and the well layer 2 during the epitaxial process, the amount of H2 introduced into the well layer 1 is greater than that introduced into the well layer 2, and the temperature of the epitaxial process is 750-900°C.

[0013] Beneficial effects:

[0014] 1. The device is provided with a built-in EBL layer, which is an AlGaN layer with a thickness ranging from 1 to 5 nm. The large bandgap width of AlGaN can effectively block electrons, improve electron utilization, and further improve luminous efficiency.

[0015] 2. The device is provided with an interface treatment layer, which is generated by introducing H2 into the reaction between the second well layer and the built-in EBL layer. The duration is 10-60 seconds. The discontinuous barrier crystal is paused to annihilate the dislocation derived from the bottom layer. The combination of gradual H2 can not only isolate the IN atoms precipitated from the quantum well light-emitting layer from penetrating into the barrier area, but also make the interface between the quantum well and the quantum barrier steeper and clearer, thereby achieving the ultimate goal of improving the lattice quality and improving the composite luminescence efficiency.

[0016] 3. The device is provided with a first well layer and a second well layer, wherein the first well layer and the second well layer are GaN barrier layers. During the epitaxial process, the temperature of the first well layer and the second well layer is increased and an appropriate amount of H2 is introduced, which can greatly improve the epitaxial quality of the GaN quantum barrier, reduce dislocation defects, and ultimately greatly improve the luminous efficiency of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the utility model.

[0018] Among them: 1. substrate, 2. buffer layer, 3. unintentional doping layer, 4. N-GaN layer, 5. well layer 1, 6. well layer 2, 7. interface treatment layer, 8. built-in EBL layer, 9. quantum well light-emitting layer, 10. P-type electron blocking layer, 11. P-GaN layer. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0023] like Figure 1 The high-light-efficiency LED epitaxial wafer structure is characterized by comprising a substrate 1, a buffer layer 2, an unintentionally doped layer 3, an N-GaN layer 4, a well layer 5, a well layer 2 6, an interface treatment layer 7, a built-in EBL layer 8, a quantum well light-emitting layer 9, a P-type electron blocking layer 10, and a P-GaN layer 11 sequentially deposited on the substrate 1;

[0024] Among them, the unintentionally doped layer 3 is a U-type GaN layer, the N-GaN layer 4 is an N-type GaN layer, the well layer 5 and the well layer 6 are GaN barrier layers, the thickness range of the well layer 5 is 0.3-0.4nm, and the thickness range of the well layer 6 is 0.2-0.3nm. In this embodiment, as a preferred scheme, the thickness of the well layer 5 is 0.3nm, the thickness of the well layer 6 is 0.2nm, and the interface treatment layer 7 is a discontinuous barrier layer, located between the well layer 6 and the built-in EBL layer 8, and the thickness of the interface treatment layer is 0.1-0.2nm. The function of the interface treatment layer is to use the paused discontinuous barrier layer to annihilate the bottom layer derived dislocations, and the combination of the gradual H2 can not only isolate the IN atoms precipitated from the quantum well light-emitting layer from penetrating into the barrier area, but also make the interface between the quantum well and the quantum barrier more steep and clear, thereby achieving the ultimate purpose of improving the lattice quality and improving the composite luminescence efficiency. The built-in EBL layer 8 is an AlGaN layer, and the thickness range of the built-in EBL layer 8 is 1-5nm. Preferably, in this embodiment, the thickness is set to 1nm. The quantum well light-emitting layer 9 mainly includes an INGaN layer. The built-in EBL layer 8 is inserted in front of the quantum well light-emitting layer 9. The electrons are blocked by the large bandgap width of AlGaN, which can improve the electron utilization rate and further improve the luminous efficiency. The P-GaN layer 11 is a P-type GaN layer. In this embodiment, sapphire (high-purity α-alumina) is selected as the substrate 1 for epitaxial growth of crystal thin films, and GaN is used as the bottom material attached to the substrate 1 as a buffer layer 2.

[0025] The specific preparation method of the structure of the utility model includes: growing a buffer layer 2 on a substrate 1, growing an unintentionally doped layer 3 on the buffer layer 2, growing an N-GaN layer 4 on the unintentionally doped layer 3, growing a well layer 5 on the N-GaN layer 4, growing a well layer 2 6 on the well layer 5, growing a built-in EBL layer 8 on the well layer 2 6, arranging an interface treatment layer 7 between the well layer 2 6 and the built-in EBL layer 8, growing a quantum well light-emitting layer 9 on the built-in EBL layer 8, growing a P-type electron blocking layer 10 on the quantum well light-emitting layer 9, and growing a P-GaN layer 11 on the P-type electron blocking layer 10. Through the design of the above structure, the utility model wherein the well layer 5 and the well layer 2 6 are heated up and gradually H2 is introduced during the epitaxial process, To reduce dislocation defects in the crystal stacking process, the amount of H2 introduced into the first well 5 is more than that into the second well 6; the amount of H2 introduced into the first well is set to be the highest, which is set at 20-50L, and is 30L in this embodiment; followed by the amount of H2 introduced into the second well, which is set at 10-30L, and is 15L in this embodiment; the introduction of H2 can greatly improve the epitaxial quality of the GaN quantum barrier, and inserting the built-in EBL layer 8 can block electrons by utilizing the large bandgap width of AlGaN, thereby improving the electron utilization rate and further improving the luminescence efficiency, thereby achieving the ultimate goal of improving the lattice quality and improving the composite luminescence efficiency, and the epitaxial temperature setting: the first well 5 is higher than the second well 6, and the temperature is set at 750-900°C, and the preferred temperature is 800°C.

[0026] The design idea of ​​the interface treatment layer 7 in this embodiment is as follows: the design idea is that the MO source is not introduced on the basis of the above structure, and the position is between the second well layer 6 and the built-in EBL layer 8. The interface treatment layer 7 is generated by introducing H2 between the second well layer and the built-in EBL layer. In this embodiment, the H2 introduced is 5L, and the duration of introducing H2 is 10-60 seconds, preferably 30 seconds. The reaction temperature range is 750-900°C, and the preferred temperature is 800°C. Under this reaction condition, an interface treatment layer with a thickness of about 0.1nm is generated between the contact surface of the second well layer 6 and the built-in EBL layer 8. The purpose of setting the interface treatment layer 7 is to annihilate the dislocations derived from the bottom layer and greatly improve the lattice quality.

[0027] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with this technology to understand the content of the utility model and implement it accordingly. They cannot be used to limit the protection scope of the utility model. All equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

[0028] In summary, the utility model achieves the expected effect.

Claims

1. A high-light-efficiency LED epitaxial wafer structure, characterized in that: It includes a substrate, a buffer layer, an unintentionally doped layer, an N-GaN layer, a well layer 1, a well layer 2, an interface treatment layer, a built-in EBL layer, a quantum well light-emitting layer, a P-type electron blocking layer, and a P-GaN layer sequentially deposited on the substrate; Among them, the unintentionally doped layer is a U-type GaN layer, the N-GaN layer is an N-type GaN layer, the well layer 1 and the well layer 2 are GaN barrier layers, the thickness range of the well layer 1 is 0.3-0.4nm, the thickness range of the well layer 2 is 0.2-0.3nm, the interface treatment layer is located between the well layer 2 and the built-in EBL layer, the built-in EBL layer is an ALGaN layer, the thickness range of the built-in EBL layer is 1-5nm, and the P-GaN layer is a P-type GaN layer.

2. A high light-efficiency LED epitaxial wafer structure as claimed in claim 1, characterized in that: The substrate is a sapphire substrate, and the buffer layer is a GaN buffer layer.

3. The high light-efficiency LED epitaxial wafer structure according to claim 1, characterized in that: The thickness of the first well layer is 0.3 nm, and the thickness of the second well layer is 0.2 nm.

4. The high light-efficiency LED epitaxial wafer structure according to claim 1, characterized in that: The interface treatment layer is generated by introducing H2 between the second well layer and the built-in EBL layer, the duration of introducing H2 is 10-60 seconds, and the reaction temperature range is 750-900°C.

5. The high light-efficiency LED epitaxial wafer structure according to claim 1, characterized in that: The thickness of the built-in EBL layer is 1 nm.

6. The high light-efficiency LED epitaxial wafer structure according to claim 1, characterized in that: H2 is introduced into the well layer 1 and the well layer 2 during the epitaxial process, the amount of H2 introduced into the well layer 1 is greater than that introduced into the well layer 2, and the temperature of the epitaxial process is 750-900°C.

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