CN119133329B

CN119133329B - LED epitaxial wafer, LED chip and method for preparing LED epitaxial wafer

Info

Publication number: CN119133329B
Application number: CN202411582980.0A
Authority: CN
Inventors: 丁昊; 谢志文; 陈铭胜; 文国昇; 金从龙
Original assignee: Jiangxi Zhao Chi Semiconductor Co Ltd
Current assignee: Jiangxi Zhao Chi Semiconductor Co Ltd
Filing date: 2024-11-07
Publication date: 2025-04-04
Anticipated expiration: 2044-11-07

Abstract

The invention provides an LED epitaxial wafer, an LED chip and a preparation method of the LED epitaxial wafer, which belong to the technical field of light-emitting diodes, wherein the LED epitaxial wafer comprises a substrate and an epitaxial layer, the epitaxial layer comprises an n-type window layer, an n-type semiconductor layer, an active layer, a P-type semiconductor layer and a P-type window layer which are sequentially stacked, the P-type window layer comprises superlattice units which are periodically distributed, the superlattice unit comprises an Al _xIn_1‑x P sublayer, a Ga _xIn_1‑x P sublayer and a GaP sublayer which are sequentially stacked, wherein the forbidden band widths and the doping concentrations of three sublayers in the same superlattice unit are different, the doping concentration of the Ga _xIn_1‑x P sublayer in the same superlattice unit is higher than the doping concentration of the other two sublayers, and the doping concentration of the same sublayer in the superlattice unit is gradually increased along the stacking direction. According to the invention, the superlattice structure is introduced into the p-type window layer, so that the current injection efficiency can be improved, and the light absorption degree can be reduced.

Description

LED epitaxial wafer, LED chip and preparation method of LED epitaxial wafer

Technical Field

The invention relates to the technical field of light emitting diodes, in particular to an LED epitaxial wafer, an LED chip and a preparation method of the LED epitaxial wafer.

Background

In recent years, alGaInP quaternary high-brightness light-emitting diodes (LEDs) are widely applied, and compared with the traditional GaP, gaAs and GaAlAs materials, the AlGaInP quaternary high-brightness light-emitting diodes (LEDs) have the advantages of wide direct transition band GaP, high luminous efficiency, strong current bearing capacity, good stability, good temperature resistance and the like, and play an increasingly important role in the fields of signal lamps, vehicle interior and exterior indicator lamps, traffic lamps, mobile phones, electronic instruments, indoor and outdoor display, information processing, communication and the like.

The conventional structure of the AlGaInP quaternary high-brightness light-emitting diode comprises a substrate, an epitaxial wafer, an n-type electrode and a p-type electrode, wherein the conventional structure of the epitaxial wafer comprises an n-type window layer, an n-type semiconductor layer, active layers alternately distributed by GaInP/AlGaInP, a p-type semiconductor layer and a p-type window layer, the main component of the p-type window layer is GaP doped Mg, and the p-type window layer mainly plays a role of a current expansion layer.

But during operation of the light emitting diode the current is laterally spread through the p-type window layer, during which process the current is injected into the active layer. Because the current expansion capability of the p-type window layer with the main component GaP is limited, the current density of the region of the p-type current expansion layer near the lower part of the p-type electrode is higher, and the current density of the region far away from the p-type electrode is lower, the overall current injection efficiency is lower, the light emitting efficiency of the LED is reduced, and the thickness of the p-type window layer with the main component GaP is generally set thicker, so that the light emitting efficiency of the LED is further reduced due to the fact that the emergent light is absorbed to a larger extent.

Disclosure of Invention

Based on the above, the invention aims to provide an LED epitaxial wafer, an LED chip and a preparation method of the LED epitaxial wafer, which aim to innovate a p-type window layer so as to improve the current injection efficiency of the p-type window layer and reduce the light absorption degree of the p-type window layer, thereby realizing the aim of improving the light emitting efficiency of a light emitting diode.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

In a first aspect, the invention provides an LED epitaxial wafer, including a substrate and an epitaxial layer, where the epitaxial layer is disposed on one side of the substrate, the epitaxial layer includes an n-type window layer, an n-type semiconductor layer, an active layer, a P-type semiconductor layer, and a P-type window layer that are sequentially stacked, the P-type window layer includes superlattice units periodically distributed along a stacking direction, the superlattice units include Al _xIn_1-x P sublayers, ga _xIn_1-x P sublayers, and GaP sublayers that are sequentially stacked, where the forbidden band widths and doping concentrations of three sublayers in the same superlattice unit are different, the x range is 0.5 +.x1, the doping concentration of Ga _xIn_1-x P sublayers in the same superlattice unit is high Yu Tongyi, and the doping concentration of the same sublayers in the superlattice unit is gradually increased along the stacking direction.

Further, the doping sources of the Al _xIn_1-x P sub-layer, the Ga _xIn_1-x P sub-layer and the GaP sub-layer are Mg or Zn.

Further, the doping concentration of the doping source is 1.0×10 ¹⁸atoms/cm³~1.0×10²⁰atoms/cm³.

Further, the thickness of the Al _xIn_1-x P sub-layer is 20 nm-50 nm, the thickness of the Ga _xIn_1-x P sub-layer is 50 nm-100 nm, and the thickness of the GaP sub-layer is 50 nm-100 nm.

Further, the period of the superlattice unit is 10-50.

In a second aspect, the invention provides an LED chip, including the foregoing LED epitaxial wafer, and a connection electrode formed on the LED epitaxial wafer.

In a third aspect, the invention provides a method for preparing an LED epitaxial wafer, including the following steps:

Providing a substrate;

growing an n-type window layer on the substrate;

growing an n-type semiconductor layer on the n-type window layer;

growing an active layer on the n-type semiconductor layer;

Growing a p-type semiconductor layer on the active layer;

And growing a P-type window layer on the P-type semiconductor layer, wherein the P-type window layer comprises superlattice units periodically distributed along the stacking direction, the superlattice units comprise Al _xIn_1-x P sublayers, ga _xIn_1-x P sublayers and GaP sublayers which are sequentially stacked, the forbidden band widths and doping concentrations of three sublayers in the same superlattice unit are different, the value range of x is 0.5-1, the doping concentration of Ga _xIn_1-x P sublayers in the same superlattice unit is higher than that of other sublayers in the Yu Tongyi superlattice unit, and the doping concentration of the same sublayers in the superlattice unit is gradually increased along the stacking direction.

Further, a MOVCD technology is adopted to grow a p-type window layer on the active layer, wherein the growth temperature is set to 650-800 ℃, the growth pressure is set to 40-60 mbar, the doping source is Mg or Zn, and the doping concentration is set to 1.0X10 ¹⁸atoms/cm³~1.0×10²⁰atoms/cm³.

The LED chip has the advantages that the LED chip at least comprises the P-type window layers comprising the Al _xIn_1-x P sub-layers, the Ga _xIn_1-x P sub-layers and the GaP sub-layers which are alternately arranged and have different forbidden band widths and doping concentrations, so that energy band bending and potential barriers are formed at the interfaces of the sub-layers, the transmission characteristics of carriers can be regulated and controlled by energy band change, the current expansion effect is improved, meanwhile, the activation of doping sources In the relevant sub-layers can be promoted by adding In, the energy band structures are optimized, the conductivity of the energy band structures is improved, and compared with the conventional P-type window layers with the GaP main component, the thickness of the P-type window layers can be greatly reduced while the light absorption degree of the P-type window layers is reduced, and the light emitting efficiency of the LED chip is further improved.

Drawings

Fig. 1 is a schematic structural diagram of an LED epitaxial wafer according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an LED chip according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a p-type window layer according to an embodiment of the present invention;

fig. 4 is a flowchart of a method for manufacturing an LED epitaxial wafer according to an embodiment of the present invention;

description of main reference numerals:

The semiconductor device comprises a substrate-100, a buffer layer-110, a stop layer-120, an epitaxial layer-200, an n-type window layer-210, an n-type semiconductor layer-220, an active layer-230, a P-type semiconductor layer-240, a P-type window layer-250, a superlattice unit-251, an Al _xIn_1-x P sub-layer-2511, a Ga _xIn_1-x P sub-layer-2512, a GaP sub-layer-2513, a contact layer-260, a DBR reflection layer-270, an n-type electrode-500, a P-type electrode-600 and a bonding pad 700;

The invention will be further described in the following detailed description in conjunction with the above-described figures.

Detailed Description

In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "mounted" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.

Unless defined otherwise, 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 terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

The AlGaInP material has the property of direct transition, the efficiency of composite luminescence is high, so that the luminous efficiency is high, the AlGaInP material belongs to a wide forbidden band material, the forbidden band width can be adjusted continuously along with the change of an In component, and therefore high-brightness luminescence of an LED In an ultra-wide wavelength range from red light to blue-green light, from 560nm to 650nm, can be realized, and In addition, the AlGaInP material can be transited from a direct band gap to an indirect band gap, and the energy level range is 1.9eV to 2.3eV.

Based on the content in the background art, the main component of the p-type window layer of the traditional light-emitting diode prepared based on AlGaInP material is GaP doped with Mg, and when the light-emitting diode works, current transversely expands through the p-type window layer, so that the current is injected into the active layer. However, the current expansion capability of the p-type window layer with the GaP as the main component is limited, so that the current density of the region of the p-type window layer near the lower part of the p-type electrode is higher, and the current density of the region far away from the p-type electrode is lower, which finally results in lower overall current injection efficiency and reduces the light emitting efficiency of the LED. Moreover, in order to provide better current distribution and reduce current collection, the thickness of the p-type window layer with the main component GaP is usually set relatively thick, which results in a greater absorption of outgoing light by the p-type window layer, further reducing the light-emitting efficiency of the light-emitting diode.

Based on the structure, the application provides an LED epitaxial wafer, an LED chip and a preparation method of the LED epitaxial wafer, the current expansion effect is improved by setting the p-type window layer as a superlattice structure, meanwhile, the thickness of the p-type window layer can be reduced, the light absorption effect of the p-type window layer is reduced, and the aim of improving the light emitting efficiency of the light emitting diode is achieved.

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.

Referring to fig. 1, an LED epitaxial wafer according to an embodiment of the present invention includes a substrate 100 and an epitaxial layer 200, wherein the epitaxial layer 200 is disposed on one side of the substrate 100, and the epitaxial layer 200 includes an n-type window layer 210, an n-type semiconductor layer 220, an active layer 230, a p-type semiconductor layer 240, and a p-type window layer 250 stacked in sequence.

The substrate 100 may be any one or any combination of a sapphire substrate, a silicon carbide substrate, a gallium nitride substrate, a gallium oxide substrate, and a gallium arsenide substrate. In addition, since AlGaInP lattice is perfectly matched with that of the GaAs substrate, a high quality LED epitaxial wafer can be manufactured on the GaAs substrate, for which the substrate 100 is preferably a GaAs substrate. The n-type window layer 210 may be any one of an AlInP window layer having n-type doping, an AlGaInP window layer having n-type doping, or a combination of both. The n-type semiconductor layer 220 may be any one of an AlGaInP layer having n-type doping, an AlInP layer having n-type doping, or a combination of both. The active layer 230 may be a multiple quantum well structure, specifically, active layers alternately arranged of GaInP/AlGaInP, and the forbidden bandwidth of the AlGaInP material may be changed by changing the In composition. The p-type semiconductor layer 240 may be any one of an AlGaInP layer having p-type doping, an AlInP layer having p-type doping, or a combination of both. The P-type window layer 250 includes superlattice units 251 periodically distributed in the stacking direction, and the superlattice units 251 include an Al _xIn_1-x P sub-layer 2511, a Ga _xIn_1-x P sub-layer 2512, and a GaP sub-layer 2513, which are stacked in this order.

In order to achieve the object of the present application, the structure of the p-type window layer 250 is optimized in this embodiment, which is specifically expressed in the following aspects:

first, because the value range of x is related to the forbidden bandwidth of the quantum well layer in the active layer 230 of the multi-quantum well structure, in order to ensure that the forbidden bandwidth of the p-type window layer 250 is always larger than the forbidden bandwidth of the quantum well layer in the active layer 230, the non-radiative recombination generated by light absorption due to the small forbidden bandwidth is avoided. Therefore, in this embodiment, the value range of x is set to 0.5+.x <1.

Secondly, first, since the forbidden bandwidths of the Al _xIn_1-x P sub-layer 2511, the Ga _xIn_1-x P sub-layer 2512, and the GaP sub-layer 2513 are related to the respective doping concentrations. In addition, the Al _xIn_1-x P sub-layer 2511 with a large forbidden bandwidth and a high potential barrier can further reduce the overflow of electrons to the P-type layer to generate non-radiative recombination, so that the light emitting efficiency of the light emitting diode is improved, a certain potential barrier difference is generated between the Ga _xIn_1-x P sub-layer 2512 and the GaP sub-layer 2513, the inflow of holes to the active layer 230 can be promoted, and the injection efficiency of the holes is improved. Meanwhile, the activation energy of the doping source is positively correlated with the Al component, the higher the Al component is, the higher the activation energy of the doping source is, the In is used for reducing the activation energy of the doping source, and the proper In can effectively reduce the activation energy of the doping source and improve the concentration of the activated doping source. Therefore, in the present embodiment, the forbidden bandwidths and doping concentrations of the Al _xIn_1-x P sub-layer 2511, the Ga _xIn_1-x P sub-layer 2512, and the GaP sub-layer 2513 in the same superlattice unit 251 are all set to be different, and the doping concentration of the Ga _xIn_1-x P sub-layer 2512 in the same superlattice unit 251 is set to be higher than the doping concentration of the Al _xIn_1-x P sub-layer 2511 in the Yu Tongyi superlattice unit 251, while the doping concentration of the Ga _xIn_1-x P sub-layer 2512 in the same superlattice unit 251 is set to be higher than the doping concentration of the GaP sub-layer 2513 in the Yu Tongyi superlattice unit 251.

Thirdly, along with the increase of the growth period of the superlattice unit 251, the doping concentration of the Ga _xIn_1-x P sub-layer 2512 gradually rises, so that the crystal quality of the P-type window layer 250 can be improved, and the abnormal problems of coarsening, protruding and the like on the surface of the epitaxial wafer caused by high doping concentration are avoided. Meanwhile, as the doping concentration of the Ga _xIn_1-x P sub-layer 2512 is gradually increased, the uniformity of holes flowing from the P-type layer to the active layer 230 can be improved, so that the thickness of the P-type window layer 250 can be reduced, the degree of light emitted by the P-type window layer 250 can be reduced, and the light emitting efficiency of the light emitting diode can be further improved. In addition, the higher the doping concentration of the p-type window layer 250 near the electrode side, the contact resistance can be reduced, and the electro-optical conversion efficiency can be improved. Accordingly, the doping concentration of the Al _xIn_1-x P sub-layer 2511 in all the superlattice cells 251 is set to be gradually increased in the stacking direction in the present embodiment, the doping concentration of the Ga _xIn_1-x P sub-layer 2512 in all the superlattice cells 251 is also set to be gradually increased in the stacking direction, and the doping concentration of the GaP sub-layer 2513 in all the superlattice cells 251 is also set to be gradually increased in the stacking direction.

In some alternative embodiments, the doping sources of Al _xIn_1-x P sub-layer 2511, ga _xIn_1-x P sub-layer 2512, and GaP sub-layer 2513 are each Mg or Zn, with a doping concentration of 1.0×10 ¹⁸atoms/cm³~1.0×10²⁰atoms/cm³.

In some alternative embodiments, the Al _xIn_1-X P sub-layer 2511 has a thickness of 20nm to 50nm, the Ga _xIn_1-x P sub-layer 2512 has a thickness of 50nm to 100nm, and the GaP sub-layer 2513 has a thickness of 50nm to 100nm.

In some alternative embodiments, the period of the superlattice unit 251 is 10-50.

In a second aspect, as shown in fig. 2, the present invention further provides an LED chip, including the foregoing LED epitaxial wafer, and an n-type electrode 500 and a p-type electrode 600 formed on the LED epitaxial wafer. Illustratively, the LED chip is constructed in a flip-chip structure including a sapphire substrate, an epitaxial layer 200 bonded on the sapphire substrate, and n-type electrodes 500 and p-type electrodes 600 connected to the epitaxial layer 200. The epitaxial layer 200 includes a contact layer 260, a P-type window layer 250, a P-type semiconductor layer 240, an active layer 230, an n-type semiconductor layer 220, an n-type window layer 210, and a DBR reflection layer 270, where the P-type window layer 250 includes superlattice units 251 periodically distributed along a stacking direction, the superlattice units 251 include Al _xIn_1-x P sub-layers 2511, ga _xIn_1-x P sub-layers 2512, and GaP sub-layers 2513 stacked in sequence, a value range of x is set to 0.5 + <1, a forbidden band width and a doping concentration of Al _xIn_1-x P sub-layers 2511, ga _xIn_1-x P sub-layers 2512, and GaP sub-layers 2513 in the same superlattice unit 251 are different, and a doping concentration of Ga _xIn_1-x P sub-layers 2512 in the same superlattice unit 251 is high Yu Tongyi, a doping concentration of Ga _xIn_1-x P sub-layers 2511 in the same superlattice unit 251 is high, a doping concentration of Ga _xIn_1-x P sub-layers 2512 in the same superlattice unit 251 is high, and a doping concentration of all the superlattice units 2513 in the same superlattice unit 251 is gradually increased along a stacking direction, and the doping concentrations of all the superlattice units 251 are gradually increased along the stacking direction of the superlattice units 251.

In a third aspect, as shown in fig. 4, the embodiment of the present invention further provides a method for preparing the foregoing LED epitaxial wafer, which specifically includes steps S10 to S60:

S10, providing a substrate 100, where the substrate 100 may be any one or any combination of a sapphire substrate, a silicon carbide substrate, a gallium nitride substrate, a gallium oxide substrate, and a gallium arsenide substrate. Because the AlGaInP crystal lattice is perfectly matched with the crystal lattice of the gallium arsenide substrate, a high-quality LED epitaxial wafer can be manufactured on the gallium arsenide substrate, the gallium arsenide substrate is mature in manufacturing process and high in stability, the cost performance is high, and the gallium arsenide substrate is preferred as the substrate 100.

And S20, growing an n-type window layer 210 on the substrate 100, wherein the n-type window layer 210 is mainly used for forming an n-type contact semiconductor layer so as to finish injection and export of current. Alternatively, the n-type window layer 210 may be any one or a combination of an AlInP window layer and an AlGaInP window layer.

The n-type window layer 210 is an AlGaInP window layer with n-type doping, and the specific deposition process of the Metal Organic Chemical Vapor Deposition (MOCVD) technology is that the temperature of a reaction chamber is controlled to be 600-700 ℃, TMAL (trimethylaluminum) is used as an aluminum source, TMGa (trimethylgallium) is used as a gallium source, TMIn (trimethylindium) is used as an indium source, PH ₃ (phosphine) is used as a phosphorus source, and the growth thickness of the deposited AlGaInP window layer is controlled to be 200-500 nm.

S30, an n-type semiconductor layer 220 is grown on the n-type window layer 210, and the n-type semiconductor layer 220 is mainly used for providing n-type carriers. Alternatively, the n-type semiconductor layer 220 may be any one of an AlGaInP layer having n-type doping, an AlInP layer having n-type doping, or a combination of both.

The n-type semiconductor layer 220 is an AlInP layer with n-type doping, and the specific deposition process of the Metal Organic Chemical Vapor Deposition (MOCVD) technology is that the temperature of a reaction chamber is controlled to be 650-750 ℃, the pressure of the reaction chamber is controlled to be 40-60 mbar, TMAL (trimethylaluminum) is used as an aluminum source, TMIn (trimethylindium) is used as an indium source, PH ₃ (phosphine) is used as a phosphorus source, si ₂H₆ (disilane) is used as a dopant, the doping concentration of Si is 1.0x10 ¹⁷atoms/cm³～1.0×10¹⁹atoms/cm³, and the growth thickness of the deposited AlInP layer is controlled to be 100-450 nm.

S40, an active layer 230 is grown on the n-type semiconductor layer 220, specifically, the active layer 230 is an active layer with GaInP/AlGaInP alternately arranged, and the forbidden bandwidth of the AlGaInP material can be changed by changing the In composition.

The specific deposition process of the Metal Organic Chemical Vapor Deposition (MOCVD) technology is that the temperature of a reaction chamber is controlled to be 620-720 ℃, TMAL (trimethylaluminum) is used as an aluminum source, TMGa (trimethylgallium) is used as a gallium source, TMIn (trimethylindium) is used as an indium source, PH ₃ (hydrogen phosphide) is used as a phosphorus source, the thickness of an AlGaInP barrier layer is 60-200A, the thickness of a GaInP well layer is 30-80A, and the period of the alternate arrangement is 8-18.

S50, a p-type semiconductor layer 240 is grown on the active layer 230, and the p-type semiconductor layer 240 is mainly used to provide p-type carriers. Alternatively, the p-type semiconductor layer 240 may be any one of an AlGaInP layer having p-type doping, an AlInP layer having p-type doping, or a combination of both.

Since the n-type semiconductor layer 220 and the p-type semiconductor layer 240 each have a composition of a high A1 component, a forbidden bandwidth is larger than that of the active layer 230, and thus a minority carrier confinement effect can be achieved, so that electron-hole pairs are effectively confined in the active layer 230, thereby increasing the probability of electron-hole recombination, improving the luminous efficiency of the LED, and since the forbidden bandwidths of the n-type semiconductor layer 220 and the p-type semiconductor layer 240 are large, most of light emitted from the light emitting region is not absorbed when passing through the n-type semiconductor layer 220 and the p-type semiconductor layer 240, thereby improving the external quantum efficiency of the LED.

The p-type semiconductor layer 240 is an AlInP layer with p-type doping, and the specific deposition process of the Metal Organic Chemical Vapor Deposition (MOCVD) technology is that the temperature of a reaction chamber is controlled to be 700-800 ℃, the pressure of the reaction chamber is controlled to be 40-60 mbar, TMAL (trimethylaluminum) is used as an aluminum source, TMIn (trimethylindium) is used as an indium source, PH ₃ (phosphine) is used as a phosphorus source, CP ₂ Mg (dipentylmagnesium) is used as a dopant, the doping concentration of Mg is 1.0x10 ¹⁷atoms/cm³～1.0×10¹⁹atoms/cm³, and the thickness of the grown AlInP layer is 100-550 nm.

S60, a p-type window layer 250 is grown on the p-type semiconductor layer 240.

Specifically, as shown in fig. 3, the P-type window layer 250 includes superlattice units 251 periodically distributed in the stacking direction, and the superlattice units 251 include Al _xIn_1-x P sub-layer 2511, ga _xIn_1-x P sub-layer 2512, and GaP sub-layer 2513, which are stacked in this order.

The P-type window layer 250 is formed by a Metal Organic Chemical Vapor Deposition (MOCVD) technique, wherein the temperature of the reaction chamber is controlled to 650-800 ℃, the pressure of the reaction chamber is controlled to 40-60 mbar, TMAL (trimethylaluminum) is used as an aluminum source, TMIn (trimethylindium) is used as an indium source, TMGa (trimethylgallium) is used as a gallium source, PH ₃ (phosphine) is used as a phosphorus source, CP ₂ Mg (dipentaerythritol magnesium) is used as a dopant, al _xIn_1-x P sub-layer 2511 with the thickness of 20-50 nm, mg doping concentration in the Al _xIn_1-x P sub-layer 2511 is 1.0x10 ¹⁸atoms/cm³～1.0×10²⁰atoms/cm³, ga _xIn_1-x P sub-layer 2512 with the thickness of 50-100 nm, mg doping concentration in the Ga _xIn_1-x P sub-layer 2512 is 1.0x10 ¹⁸atoms/cm³～1.0×10²⁰atoms/cm³, and Mg doping concentration in the GaP sub-layer 2513 with the thickness of 50-100 nm is 1.0x10. And repeating the steps, and finally depositing 10-50 alternately arranged Mg-doped Al _xIn_1-x P sublayers 2511, ga _xIn_1-x P sublayers 2512 and GaP sublayers 2513.

The forbidden bandwidths and doping concentrations of the Al _xIn_1-x P sub-layer 2511, the Ga _xIn_1-x P sub-layer 2512 and the GaP sub-layer 2513 in the same superlattice unit 251 are different, and the value range of x is 0.5-1. In addition, the doping concentration of the Ga _xIn_1-x P sub-layer 2512 in the same superlattice unit 251 is higher than the doping concentration of the Al _xIn_1-x P sub-layer 2511 in the Yu Tongyi superlattice unit 251, and is also higher than the doping concentration of the GaP sub-layer 2513 in the same superlattice unit 251, the doping concentration of the Al _xIn_1-x P sub-layer 2511 in all superlattice units 251 in the stacking direction is gradually increased, the doping concentration of the Ga _xIn_1-x P sub-layer 2512 in all superlattice units 251 in the stacking direction is also gradually increased, and the doping concentration of the GaP sub-layer 2513 in all superlattice units 251 in the stacking direction is also gradually increased.

In some alternative embodiments, the following step S11 is further included between steps S10 and S20:

Step S11 is to grow the buffer layer 110 on the substrate 100, where the purpose of the buffer layer 110 is to provide an intermediate layer between two different materials to improve the interface characteristics between them, reduce defects, and improve the stability and performance of the overall structure, so that the buffer layer 110 needs to be dependent on the materials used for the substrate 100 and the n-type window layer 210.

Illustratively, the substrate 100 is a GaAs substrate, the n-type window layer 210 is an AlGaInP window layer with n-type doping, the buffer layer 110 is a GaAs buffer layer with Si doping, and a specific deposition process of a Metal Organic Chemical Vapor Deposition (MOCVD) technology is that the temperature of a reaction chamber is controlled to be 600-700 ℃, TMGa (trimethylgallium) is used as a gallium source, asH ₃ (arsine) is used as an arsenic source, si ₂H₆ (disilane) is used as a dopant, the doping concentration of Si is 1.0x ¹⁶atoms/cm³～1.0×10¹⁹atoms/cm³, and the GaAs buffer layer with the thickness of 100-400 nm is grown.

In some alternative embodiments, the following step S12 is further included between steps S11 and S20:

In step S12, a stop layer 120 is grown on the buffer layer 110, wherein the stop layer 120 is mainly used for improving the selectivity when the GaAs substrate is stripped by wet etching, and preventing the epitaxial layer 200 from being corroded by corrosive liquid medicine. Alternatively, the cut-off layer 120 may be any one or any combination of AlGaInP cut-off layers and GaInP cut-off layers.

The stop layer 120 is illustratively a Si-doped GaInP stop layer, and a specific deposition process using a Metal Organic Chemical Vapor Deposition (MOCVD) technique is to control the temperature of a reaction chamber to 650 ℃ to 750 ℃, to use TMGa (trimethylgallium) as a gallium source, TMIn (trimethylindium) as an indium source, PH ₃ (phosphine) as a phosphorus source, si ₂H₆ (disilane) as a dopant, si doping concentration to 1.0×10 ¹⁶atoms/cm³～1.0×10¹⁹atoms/cm³, and to grow an inp stop layer with a thickness of 250nm to 800 nm.

In some alternative embodiments, as shown in fig. 2, a contact layer 260 is deposited on the p-type window layer 250, the contact layer 260 primarily serving to form an ohmic contact.

Because the GaAs substrate absorbs the outgoing light to a larger extent, the light-emitting efficiency of the LED is reduced, and therefore, in this embodiment, the sapphire substrate is bonded on the contact layer 260, the LED epitaxial wafer is inverted, the GaAs substrate, the GaAs buffer layer, and the GaInP cut-off layer are stripped and removed until the n-type window layer 210 is exposed, then the n-type window layer 210 is etched until the p-type window layer 250 is exposed, then the n-type electrode 500 is fabricated on the n-type window layer 210, and the p-type electrode 600 is fabricated on the exposed p-type window layer 250.

In some alternative embodiments, as shown in fig. 2, in order to further improve the light emitting efficiency of the light emitting diode, a DBR reflective layer 270 is evaporated on the epitaxial layer 200 on the n-type window layer 210 side, and the DBR reflective layer 270 may be made of AlAs/AlGaAs material, where the DBR reflective layer 270 mainly performs passivation and reflection functions. Meanwhile, in order to lead out the connection electrode, the DBR reflection layer 270 is further perforated so that the pad 700 electrically connects the n-type electrode 500 and the p-type electrode 600. Finally, the sapphire substrate is thinned, and then laser cutting is carried out to separate the AlGaInP light-emitting diode chip with the flip-chip structure of the designed size.

The invention is further illustrated by the following examples:

embodiment one:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, which includes a sapphire substrate and an epitaxial layer 200 bonded on the sapphire substrate, wherein the epitaxial layer 200 includes a contact layer 260, a p-type window layer 250, a p-type semiconductor layer 240, an active layer 230, an n-type semiconductor layer 220, and an n-type window layer 210, which are stacked in order. The P-type window layer 250 includes superlattice units 251 periodically distributed along the stacking direction, the growth period of the superlattice units 251 is 30, and the superlattice units 251 include an Al _xIn_1-x P sub-layer 2511, a Ga _xIn_1-x P sub-layer 2512, and a GaP sub-layer 2513 that are stacked in sequence. Specifically, the value of x is 0.5, the doping concentration of the Al _xIn_1-x P sub-layer 2511 doped with Mg in the first grown superlattice unit 251 is 1.1x10 ¹⁸atoms/cm³,Al_xIn_1-x P sub-layer 2511, the forbidden band width of the Al _xIn_1-x P sub-layer 2511 is 1.9ev, the thickness of the Al _xIn_1-x P sub-layer 2511 is 32nm, the doping concentration of the Ga _xIn_1-x P sub-layer 2512 doped with Mg in the first grown superlattice unit 251 is 1.2x10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512, the forbidden band width of the Ga 38362P sub-layer 2512 is 1.6ev, the thickness of the Ga _xIn_1-x P sub-layer 2512 is 73nm, the doping concentration of the GaP sub-layer 2513 doped with Mg in the first grown superlattice unit 251 is 1.1x10 ¹⁸atoms/cm³, the forbidden band width of the GaP sub-layer 2513 is 1.85ev, and the thickness of the GaP sub-layer 2513 is 68nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by a magnitude of 5%.

Embodiment two:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the first embodiment, in this embodiment, the growth period of the superlattice unit 251 is 27, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 1.0×10 ¹⁸atoms/cm³,Al_xIn_1-x P sub-layer 2511 with a thickness of 25nm, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 1.5×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 with a thickness of 82nm, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.3×10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 59nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by 3%.

Embodiment III:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the first embodiment, in this embodiment, the growth period of the superlattice unit 251 is 34, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 29nm, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 2.0×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 doped with elemental Mg is 63nm, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.2×10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 71nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by 6%.

Embodiment four:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the first embodiment, in this embodiment, the growth period of the superlattice unit 251 is 31, the value of x is 0.6, the doping concentration of the doping element Mg of the Al _xIn_1-x P sub-layer 2511 in the first grown superlattice unit 251 is 1.6x10 ¹⁸atoms/cm³,Al_xIn_1-x P sub-layer 2511, the bandgap width of the Al _xIn_1-x P sub-layer 2511 is 2.01ev, the thickness of the Al _xIn_1-x P sub-layer 2511 is 38nm, the doping concentration of the doping element Mg of the Ga _xIn_1-x P sub-layer 2512 in the first grown superlattice unit 251 is 2.1x10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512, the thickness of the Ga _xIn_1-x P sub-layer 2512 is 69nm, the doping concentration of the doping element Mg of the GaP sub-layer 2513 in the first grown superlattice unit 251 is 1.6x10 ¹⁸atoms/cm³, and the thickness of the GaP sub-layer 2513 is 57nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by 4%.

Fifth embodiment:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the fourth embodiment, in this embodiment, the growth period of the superlattice unit 251 is 28, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 26nm in thickness, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 1.3×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 doped with elemental Mg in thickness is 73nm, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.1×10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 69nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by a magnitude of 5%.

Example six:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the fourth embodiment, in this embodiment, the growth period of the superlattice unit 251 is 29, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 27nm, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 1.7x10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 doped with elemental Mg is 58nm, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.3x10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 75nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the superlattice unit 251 adjacent in the stacking direction increases by 7%.

Embodiment seven:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the first embodiment, in this embodiment, the growth period of the superlattice unit 251 is 33, the value of x is 0.7, the band GaP width of the Al _xIn_1-x P sub-layer 2511 in the first grown superlattice unit 251 is 2.12ev, the thickness of the Al _xIn_1-x P sub-layer 2511 is 28nm, the doping concentration of the Ga _xIn_1-x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 1.9×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512, the band GaP width of the Ga _xIn_1-x P sub-layer 2512 is 1.7ev, the thickness of the Ga _xIn_1-x P sub-layer 2512 is 65nm, the doping concentration of the GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.5×10 ¹⁸atoms/cm³, and the thickness of the GaP sub-layer 2513 is 73nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by 3%.

Example eight:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the seventh embodiment, in this embodiment, the growth period of the superlattice unit 251 is 27, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 25nm in thickness, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 2.5×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 is 71nm in thickness, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.2×10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 65nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by a magnitude of 5%.

Example nine:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the seventh embodiment, in this embodiment, the growth period of the superlattice unit 251 is 31, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 31nm in thickness, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 2.3×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 is 53nm in thickness, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.7×10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 82nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by 6%.

Example ten:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the first embodiment, in this embodiment, the growth period of the superlattice unit 251 is 35, the value of x is 0.8, the doping concentration of the doping element Mg of the Al _xIn_1-x P sub-layer 2511 in the first grown superlattice unit 251 is 1.9x10 ¹⁸atoms/cm³,Al_xIn_1-x P sub-layer 2511, the bandgap width of the Al _xIn_1-x P sub-layer 2511 is 2.23ev, the thickness of the Al _xIn_1-x P sub-layer 2511 is 39nm, the doping concentration of the doping element Mg of the Ga _xIn_1-x P sub-layer 2512 in the first grown superlattice unit 251 is 2.7x10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512, the thickness of the Ga _xIn_1-x P sub-layer 2512 is 68nm, the doping concentration of the doping element Mg of the GaP sub-layer 2513 in the first grown superlattice unit 251 is 1.9x10 ¹⁸atoms/cm³, and the thickness of the GaP sub-layer 2513 is 58nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the superlattice unit 251 adjacent in the stacking direction increases by 7%.

Example eleven:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the tenth embodiment, in this embodiment, the growth period of the superlattice unit 251 is 29, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 32nm in thickness, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 2.3×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 is 87nm in thickness, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.1×10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 71nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by 4%.

Embodiment twelve:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the tenth embodiment, in this embodiment, the growth period of the superlattice unit 251 is 36, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 35nm in thickness of the first 1×10 ¹⁸atoms/cm³,Al_xIn_1-x P sub-layer 2511, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 2.6× 10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 is 75nm in thickness, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.2× 10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 75nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by a magnitude of 5%.

Embodiment thirteen:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the first embodiment, in this embodiment, the growth period of the superlattice unit 251 is 34, the value of x is 0.9, the doping concentration of the doping element Mg of the Al _xIn_1-x P sub-layer 2511 in the first grown superlattice unit 251 is 1.5x ¹⁸atoms/cm³,Al_xIn_1-x P sub-layer 2511, the bandgap width of the Al _xIn_1-x P sub-layer 2511 is 2.34ev, the thickness of the doping element Mg of the Ga _xIn_1-x P sub-layer 2512 in the first grown superlattice unit 251 is 26nm, the bandgap width of the doping element Mg of the Ga _xIn_1-x P sub-layer 2512 in the first grown superlattice unit 251 is 1.9x ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 is 1.8ev, the thickness of the Ga _xIn_1-x P sub-layer 2512 is 79nm, and the thickness of the GaP sub-layer 2513 in the first grown superlattice unit 251 is 73nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by 4%.

Fourteen examples:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the thirteenth embodiment, in this embodiment, the growth period of the superlattice unit 251 is 35, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 29nm in thickness, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 2.5×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 is 65nm in thickness, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.7×10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 65nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by a magnitude of 5%.

Example fifteen:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the thirteenth embodiment, in this embodiment, the growth period of the superlattice unit 251 is 31, the doping concentration of Al _xIn_1-x P sub-layer 2511 doped with elemental Mg in the first grown superlattice unit 251 is 31nm in thickness, the doping concentration of Ga _xIn_1- _x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 2.9×10 ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 is 72nm in thickness, the doping concentration of GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.3×10 ¹⁸atoms/cm³, and the thickness of GaP sub-layer 2513 is 68nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by 6%.

Comparative example one:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the seventh embodiment, in this embodiment, the value of x is 0.45, the bandgap of the Al _xIn_1-x P sub-layer 2511 in the first grown superlattice unit 251 is 1.845ev, the thickness of the Al _xIn_1-x P sub-layer 2511 is 38nm, the doping concentration of the Ga _xIn_1-x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 2.1x ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512, the bandgap of the Ga _xIn_1-x P sub-layer 2512 is 1.575ev, the thickness of the Ga _xIn_1-x P sub-layer 2512 is 58nm, the doping concentration of the GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.2x10 ¹⁸atoms/cm³, and the thickness of the GaP sub-layer 2513 is 57nm. Further, as the growth period of the superlattice unit 251 increases, the doping concentration of the doping element Mg of the same sub-layer in the adjacent superlattice unit 251 in the stacking direction increases by a magnitude of 5%.

Comparative example two:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chip of the flip-chip structure provided in the second embodiment, in this embodiment, the value of x is 1.0, the bandgap of the Al _xIn_1-x P sub-layer 2511 in the first grown superlattice unit 251 is 2.45ev, the thickness of the Al _xIn_1-x P sub-layer 2511 is 28nm, the doping concentration of the Ga _xIn_1-x P sub-layer 2512 doped with elemental Mg in the first grown superlattice unit 251 is 1.9x ¹⁸atoms/cm³,Ga_xIn_1-x P sub-layer 2512 bandgap is 1.85ev, the thickness of the Ga _xIn_1-x P sub-layer 2512 is 69nm, the doping concentration of the GaP sub-layer 2513 doped with elemental Mg in the first grown superlattice unit 251 is 1.6x10 ¹⁸atoms/cm³, and the thickness of the GaP sub-layer 2513 is 69nm.

Comparative example three:

The present embodiment provides an AlGaInP light emitting diode chip of a flip-chip structure, unlike the AlGaInP light emitting diode chips of the flip-chip structures provided in the first to fifteen embodiments and the first and second comparative examples, in the present embodiment, the p-type window layer 250 is a p-type GaP window layer, and the doping concentration of the doping element Mg of the p-type GaP window layer is 2.1×10 ¹⁸atoms/cm³, and the thickness of the p-type GaP window layer is 6500nm.

The AlGaInP light emitting diode chips of flip-chip structures provided in examples I to fifteen and comparative examples I to III were tested under the same conditions to obtain the results of the light emission intensities obtained in the respective examples, and the degree of improvement in the light emission intensities of examples I to fifteen and comparative examples I to II was obtained with reference to the light emission intensity obtained in comparative example III, and the specific data are shown in Table 1:

TABLE 1

As can be seen from table 1, under the same test conditions, since the AlGaInP light emitting diode chip of the flip-chip structure provided in the first to fifteen embodiments of the present invention employs the p-type window layer 250 of superlattice structure to improve the current spreading effect, compared with the three p-type window layers of conventional main component GaP, the light emitting intensity is improved, and the sum of the thicknesses of the sub-layers of the p-type window layer 250 is far smaller than that of the p-type window layer of conventional main component GaP, which is beneficial to reducing the cost and avoiding the p-type window layer 250 from absorbing the outgoing light.

Meanwhile, since x in the first comparative example is set to 0.45 and x in the second comparative example is set to 1, the values of x are both outside the range of x being 0.5-1 in the AlGaInP light-emitting diode chips of the flip-chip structure provided in the first to fifteen embodiments of the present invention, and the light-emitting intensity is reduced, and the light-emitting intensity is lower than that of the AlGaInP light-emitting diode chip of the flip-chip structure of the p-type window layer with the GaP as the main component, which is likely to be caused by the fact that the x value is too high or too low and the corresponding Al content is too high or too low, thereby reducing the performance of the material.

In summary, the P-type window layer 250 is set to be the superlattice units 251 with periodic distribution, the superlattice units 251 comprise Al _xIn_1-x P sub-layers 2511, ga _xIn_1-x P sub-layers 2512 and GaP sub-layers 2513, the forbidden band widths and doping concentrations of the Al _xIn_1-x P sub-layers 2511, ga _xIn_1-x P sub-layers 2512 and GaP sub-layers 2513 In the same superlattice unit 251 are set to be different, the value range of x is set to be 0.5 less than or equal to x <1, the doping concentration of the Ga _xIn_1-x P sub-layers 2512 In the same superlattice unit 251 is high Yu Tongyi, the doping concentration of the Al _xIn_1-x P sub-layers 2511 In the superlattice unit 251 is also higher than the doping concentration of the GaP sub-layers 2513 In the same superlattice unit 251, the doping concentration of the Al _xIn_1-x P sub-layers 2511 In the superlattice unit 251 In the stacking direction is gradually increased, the doping concentration of the Ga _xIn_1-x P sub-layers 2512 In the stacking direction is also gradually increased, the doping concentrations of the GaP sub-layers 2513 In the superlattice unit 251 In the stacking direction are gradually increased, the light absorption band performance of the light absorption layer can be greatly improved, the light absorption layer can be formed, the light absorption layer performance can be greatly is improved, the light absorption performance can be greatly improved, the light absorption performance can be realized, and the performance of the light absorption layer can be greatly is improved, compared with the window performance can be formed, and the performance of the interface performance can be improved, and the performance of the performance can be improved, and the performance can be improved, compared with the performance and the performance of the performance can be well.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above examples merely represent a few embodiments of the present invention, which are described in more detail and are not to be construed as limiting the scope of the present invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. An LED epitaxial wafer, characterized in that the LED epitaxial wafer comprises:

substrate;

an epitaxial layer, arranged on one side of the substrate, the epitaxial layer comprising an n-type window layer, an n-type semiconductor layer, an active layer, a p-type semiconductor layer, and a p-type window layer stacked in sequence, the p-type window layer comprising a superlattice unit periodically distributed along a stacking direction, the superlattice unit comprising an _AlxIn1 _-xP sublayer, a _GaxIn1 _-xP sublayer, and a GaP sublayer stacked in sequence;

Among them, the doping sources of the _AlxIn1 _- xP sublayer, the _GaxIn1 _-xP sublayer and the GaP sublayer are all Mg or Zn, the bandgap width and doping concentration of the three sublayers in the same superlattice unit are different, the value range of x is 0.5≤x＜1, the doping concentration of the _GaxIn1 _-xP sublayer in the same superlattice unit is higher than the doping concentration of the other sublayers in the same superlattice unit, and the doping concentration of the same sublayer in the superlattice unit gradually increases along the stacking direction.

2 . The LED epitaxial wafer according to claim 1 , wherein the doping concentration of the doping source is 1.0×10 ¹⁸ atoms/cm ³ to 1.0×10 ²⁰ atoms/cm ³ .

3. The LED epitaxial wafer according to claim 1, characterized in that the thickness of the _AlxIn1 _-xP sublayer is 20nm~50nm, the thickness of the _GaxIn1 _-xP sublayer is 50nm~100nm, and the thickness of the GaP sublayer is 50nm~100nm.

4 . The LED epitaxial wafer according to claim 1 , wherein a period of the superlattice unit is 10 to 50.

5. An LED chip, characterized in that it comprises the LED epitaxial wafer according to any one of claims 1 to 4, and a connecting electrode formed on the LED epitaxial wafer.

6. A method for preparing an LED epitaxial wafer, characterized in that the preparation method comprises the following steps:

providing a substrate;

growing an n-type window layer on the substrate;

growing an n-type semiconductor layer on the n-type window layer;

growing an active layer on the n-type semiconductor layer;

growing a p-type semiconductor layer on the active layer;

A p-type window layer is grown on the p-type semiconductor layer, wherein the p-type window layer includes a superlattice unit periodically distributed along a stacking direction, the superlattice unit includes an _AlxIn1 _-xP sublayer, a _GaxIn1 _- xP sublayer and a GaP sublayer stacked in sequence, the doping sources of the _AlxIn1 _-xP sublayer, the _GaxIn1 _-xP sublayer and the GaP sublayer are all Mg or Zn, the bandgap widths and doping concentrations of the three sublayers in the same superlattice unit are different, the value range of x is 0.5≤x＜1, the doping concentration of the _GaxIn1 _-xP sublayer in the same superlattice unit is higher than the doping concentrations of the remaining sublayers in the same superlattice unit, and the doping concentration of the same sublayer in the superlattice unit gradually increases along the stacking direction.

7. The method for preparing an LED epitaxial wafer according to claim 6, characterized in that the p-type window layer is grown on the active layer using MOVCD technology, wherein the growth temperature is set to 650°C-800°C, the growth pressure is set to 40mbar-60mbar, the doping source is Mg or Zn, and the doping concentration is set to 1.0×10 ¹⁸ atoms/cm ³ -1.0×10 ²⁰ atoms/cm ³ .