Light-emitting diode epitaxial structure and preparation method thereof, and light-emitting diode

Abstract

The invention provides a light-emitting diode epitaxial structure, a manufacturing method thereof and a light-emitting diode, and relates to the field of semiconductor manufacturing. The light-emitting layer is arranged on one side of the first type semiconductor layer; the second type semiconductor layer is arranged on the side, away from the first type semiconductor layer, of the light-emitting layer; wherein the first-type semiconductor layer comprises a first-type ohmic contact layer and an arsenide first-type reflecting layer, the first-type reflecting layer is arranged between the first-type ohmic contact layer and the light-emitting layer, current expansion is carried out on the first-type ohmic contact layer through the first-type reflecting layer, and the arsenide first-type reflecting layer is arranged between the first-type ohmic contact layer and the light-emitting layer. And the light of the light-emitting layer is reflected. The light-emitting efficiency of the light-emitting diode can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a light emitting diode epitaxial structure and a preparation method thereof, and a light emitting diode. Background Art

[0002] A light emitting diode (LED) is a semiconductor element that can convert electric current into light of a specific wavelength range. Its light emitting principle is the energy difference between electrons moving between n-type semiconductors and p-type semiconductors, and releases energy in the form of light. Therefore, a light emitting diode is called a cold light source. It has the advantages of low power consumption, small size, high brightness, easy matching with integrated circuits, and high reliability, and is widely used as a light source. In addition, with the maturity of LED technology, the technology of LED displays or Micro LED (micro light emitting diode) displays that directly use LEDs as self-luminous display pixels is gradually being widely used.

[0003] Micro LEDs with small size and matrix structure have more advantages than LCD and OLED in wearable products and high-resolution displays. The main problem encountered by Micro LED is the low brightness under the condition of micro current density. The only way to improve the overall brightness is to use matrix structure, which increases the difficulty of the process. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention proposes a light emitting diode epitaxial structure and a preparation method thereof, and a light emitting diode, which mainly solve the problem of low light emitting brightness of the prior light emitting diode.

[0005] In order to achieve the above purpose and other purposes, the technical solution adopted by the present invention is as follows.

[0006] The present application provides a light-emitting diode epitaxial structure, comprising: a first-type semiconductor layer; a light-emitting layer, arranged on one side of the first-type semiconductor layer; and a second-type semiconductor layer, arranged on the side of the light-emitting layer away from the first-type semiconductor layer; wherein the first-type semiconductor layer comprises a first-type ohmic contact layer and a first-type reflective layer of an arsenide system, the first-type reflective layer is arranged between the first-type ohmic contact layer and the light-emitting layer, and the first-type reflective layer is used to expand the current of the first-type ohmic contact layer and reflect the light of the light-emitting layer.

[0007] In an embodiment of the present application, the first type reflective layer includes a plurality of substructure layers, each of the substructure layers includes a plurality of cyclic pairs, and each of the cyclic pairs is obtained by stacking a first reflective sublayer and a second reflective sublayer.

[0008] In one embodiment of the present application, the material of the first reflective sublayer includes Al x1 Ga 1-x1 As, the material of the second reflective sublayer includes Al x2 Ga 1-x2 As, the value range of x1 is between 0.5 and 0.55, and the value range of x2 is between 0.9 and 0.95.

[0009] In one embodiment of the present application, the Al component in each of the cycle pairs is the same.

[0010] In one embodiment of the present application, the first type reflective layer includes a first substructure layer, a second substructure layer and a third substructure layer stacked in sequence toward the light-emitting layer, and the first substructure layer, the second substructure layer and the third substructure layer have the same doping concentration range and doping elements.

[0011] In one embodiment of the present application, the doping element includes magnesium, and the doping concentration range is between 9×10 17 cm -3 to 2x10 18 cm -3 The growth thickness of the first sub-reflection layer and the second sub-reflection layer of the first sub-structure layer is between 45nm and 55nm, the growth thickness of the first sub-reflection layer and the second sub-reflection layer of the second sub-structure layer is between 40nm and 50nm, and the growth thickness of the first sub-reflection layer and the second sub-reflection layer of the third sub-structure layer is between 35nm and 45nm.

[0012] In one embodiment of the present application, the number of cyclic pairs of the first substructure layer is between 3 and 8 pairs, the number of cyclic pairs of the second substructure layer is between 3 and 8 pairs, and the number of cyclic pairs of the third substructure layer is between 17 and 22 pairs.

[0013] The present application also provides a method for preparing an epitaxial structure of a light-emitting diode, comprising: providing a substrate; making an epitaxial structure on the substrate, the epitaxial structure comprising: a first-type semiconductor layer, the first-type semiconductor layer being arranged on one side of the substrate; a light-emitting layer being arranged on one side of the first-type semiconductor layer; and a second-type semiconductor layer being arranged on a side of the light-emitting layer away from the first-type semiconductor layer; wherein the first-type semiconductor layer comprises a first-type ohmic contact layer and a first-type reflective layer formed by stacking a plurality of arsenide-based semiconductor layers, the first-type reflective layer being arranged between the first-type ohmic contact layer and the light-emitting layer, and current expansion of the first-type ohmic contact layer is performed through the first-type reflective layer, and light of the light-emitting layer is reflected.

[0014] In one embodiment of the present application, the preparation process of the first type reflective layer includes: setting the temperature of the reaction chamber to 650-670°C and the pressure to 50 mbar, and respectively introducing arsine as a Group V source, hydrogen as a carrier gas, trimethylaluminum and trimethylgallium as Group III sources into the first type ohmic contact layer to form the first type reflective layer composed of a plurality of substructure layers, wherein each of the substructure layers includes a plurality of groups of cyclic pairs, and each group of the cyclic pairs is obtained by stacking a first reflective sublayer and a second reflective sublayer.

[0015] The present application also provides a light-emitting diode, comprising: an epitaxial structure, the epitaxial structure comprising: a first-type semiconductor layer; a light-emitting layer, arranged on one side of the first-type semiconductor layer; and a second-type semiconductor layer, arranged on the side of the light-emitting layer away from the first-type semiconductor layer; wherein the first-type semiconductor layer comprises a first-type ohmic contact layer and a first-type reflective layer of an arsenide system, the first-type reflective layer being arranged between the first-type ohmic contact layer and the light-emitting layer, and the first-type reflective layer being used to expand the current of the first-type ohmic contact layer and reflect the light of the light-emitting layer; a first electrode, being electrically connected to the first-type ohmic contact layer; and a second electrode, being electrically connected to the second-type semiconductor layer.

[0016] As described above, the light-emitting diode epitaxial structure and the preparation method thereof, and the light-emitting diode provided in the present application have the following beneficial effects.

[0017] In the present application, a first type reflective layer is arranged between the ohmic contact layer and the light emitting layer. The first type reflective layer can not only play a role in current expansion but also improve the reflection effect on the light source, thereby enhancing the light emitting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of the light emitting diode epitaxial structure in one embodiment of the present application.

[0019] Figure 2 Schematic diagram of the structure of the first type reflective layer in one embodiment of the present application.

[0020] Figure 3 This is a method for preparing a light emitting diode epitaxial structure in an embodiment of the present application.

[0021] Figure 4 Schematic diagram of the structure of a light emitting diode in one embodiment of the present application.

[0022] Description of Figure Numbers:

[0023] 101-first type semiconductor layer, 1011-P type buffer layer, 1012-P type corrosion stop layer, 1013-P type ohmic contact layer, 1014-P type reflective layer, 1015-P type confinement layer, 1016-P type waveguide layer, 102-light emitting layer, 103-second type semiconductor layer, 1031-N type waveguide layer, 1032-N type confinement layer, 1033-N type window layer, 104-first electrode, 105-second electrode. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0025] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0026] See also Figure 1 , Figure 1 Schematic diagram of the structure of the light-emitting diode epitaxial structure in one embodiment of the present application. The light-emitting diode epitaxial structure provided in the present application includes a first-type semiconductor layer 101, a light-emitting layer 102, and a second-type semiconductor layer 103, wherein the light-emitting layer 102 can be arranged on one side of the first-type semiconductor layer 101, and the second-type semiconductor layer 103 can be arranged on the side of the light-emitting layer 102 away from the first-type semiconductor layer 101. The first-type semiconductor layer 101 includes a first-type ohmic contact layer and a first-type reflective layer of an arsenide system, and the first-type reflective layer is arranged between the first-type ohmic contact layer and the light-emitting layer 102, and the first-type reflective layer is used to expand the current of the first-type ohmic contact layer and reflect the light of the light-emitting layer 102.

[0027] See also Figure 1In one embodiment, the first type mentioned above can be P-type, and the second type can be N-type. The first type semiconductor layer 101 may include a P-type buffer layer 1011, a P-type corrosion stop layer 1012, a P-type ohmic contact layer 1013, a P-type reflective layer 1014, a P-type confinement layer 1015, and a P-type waveguide layer 1016 stacked in sequence. The light-emitting layer 102 may use a multi-quantum well structure as a light source. The second type semiconductor layer 103 includes an N-type waveguide layer 1031, an N-type confinement layer 1032, and an N-type window layer 1033 stacked in sequence, wherein the P-type waveguide layer 1016 and the N-type waveguide layer 1031 are respectively arranged on opposite sides of the light-emitting layer 102. The material of the P-type buffer layer 1011 can be P-type doped gallium arsenide GaAs, the material of the P-type corrosion stop layer 1012 can be P-type doped gallium phosphide GaP, the material of the P-type ohmic contact layer 1013 can be P-type doped GaAs gallium arsenide, the materials of the P-type confinement layer 1015 and the N-type confinement layer 1032 can both be aluminum indium phosphide AlInP, the N-type window layer 1033 can be N-type doped gallium phosphide GaP, and the P-type reflective layer 1014 can be arsenide-based materials. Conventional red light diodes usually use aluminum gallium indium phosphide AlGaInP as a current spreading layer, while the embodiment of the present application replaces the conventional current spreading layer with an arsenide-based P-type reflective layer 1014, which can not only play a role in current spreading, but also reflect the light of the multi-quantum well light source, thereby improving the luminous efficiency of the single diode.

[0028] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of the first type of reflective layer in one embodiment of the present application. The first type of reflective layer may include multiple substructure layers, each substructure layer includes multiple groups of cyclic pairs, and each group of cyclic pairs is obtained by stacking a first reflective sublayer and a second reflective sublayer. Specifically, each substructure layer can be used as a distributed Bragg reflector (DBR). When the light emitted by the multi-quantum well light source passes through the substructure layer, since the first reflective sublayer and the second reflective sublayer are alternately stacked, the first reflective sublayer and the second reflective sublayer have different refractive indices, so the light reflected back by each sublayer interferes due to the change in phase angle, forming a strong reflected light. The luminous efficiency of the light-emitting diode can be effectively improved by periodically stacking multiple cyclic pairs.

[0029] In one embodiment, the first type reflective layer can be divided into three groups, namely, a first substructure layer, a second substructure layer and a third substructure layer. Specifically, the three groups of substructure layers can be formed by growing aluminum gallium arsenide AlGaAs. The material of the first reflective sublayer may include Al x1 Ga 1-x1 As, the material of the second reflective sublayer includes Al x2 Ga 1-x2As, where x1 has a value range of 0.5 to 0.55, and x2 has a value range of 0.9 to 0.95. A cycle pair can be formed by the first reflective sublayer and the second reflective sublayer, and the cycle pair can be periodically grown to obtain the first substructure layer, the second substructure layer and the third substructure layer in sequence. The growth thickness of the cycle pairs of the three substructure layers is different. The growth thickness of the first subreflective layer and the second subreflective layer of the first substructure layer is between 45nm and 55nm, the growth thickness of the first subreflective layer and the second subreflective layer of the second substructure layer is between 40nm and 50nm, and the growth thickness of the first subreflective layer and the second subreflective layer of the third substructure layer is between 35nm and 45nm. The Al component of each cycle pair in the first substructure layer, the second substructure layer and the third substructure layer is the same, that is, the proportion of the Al component in each cycle pair is the same. For example, the proportion of the Al component in the cycle pair is 40%, and the specific Al component proportion can be configured and adjusted according to actual application requirements. During the growth of the first substructure layer, the second substructure layer, and the third substructure layer, each substructure layer can be doped. The doping element of the three substructure layers can be magnesium, and the doping concentration is between 9x10 17 cm -3 to 2x10 18 cm -3 . The number of cyclic pairs of the three substructure layers can also be set according to actual application requirements. For example, the first substructure layer can be formed by periodically stacking 3 to 8 pairs of cyclic pairs, the second substructure layer can also be formed by periodically stacking 3 to 8 pairs of cyclic pairs, and the third substructure layer can be formed by periodically stacking 17 to 22 pairs of cyclic pairs. Of course, the number of substructure layers in the first type of reflective layer can also be adjusted according to actual application requirements, and there is no restriction here. By designing the thickness and composition of different substructure layers in the first type of reflective layer, the reflection ability of the multi-quantum well light source can be effectively improved, thereby improving the luminous efficiency.

[0030] See also Figure 3 , Figure 3 A method for preparing a light emitting diode epitaxial structure in an embodiment of the present application comprises the following steps:

[0031] Step S300, providing a substrate; gallium arsenide GaAs may be used as the substrate to grow an epitaxial structure on the gallium arsenide substrate.

[0032] Step S310, fabricating an epitaxial structure on a substrate. The epitaxial structure includes a first-type semiconductor layer 101, a light-emitting layer 102, and a second-type semiconductor layer 103, wherein the light-emitting layer 102 can be disposed on one side of the first-type semiconductor layer 101, and the second-type semiconductor layer 103 can be disposed on the side of the light-emitting layer 102 away from the first-type semiconductor layer 101. The first-type semiconductor layer 101 includes a first-type ohmic contact layer and an arsenide-based first-type reflective layer, the first-type reflective layer is disposed between the first-type ohmic contact layer and the light-emitting layer 102, and the first-type reflective layer is used to expand the current of the first-type ohmic contact layer and reflect the light of the light-emitting layer 102.

[0033] In one embodiment, the first type may be P-type, and the second type may be N-type. The first type semiconductor layer 101 may include a P-type buffer layer 1011, a P-type corrosion stop layer 1012, a P-type ohmic contact layer 1013, a P-type reflective layer 1014, a P-type confinement layer 1015, and a P-type waveguide layer 1016. The light emitting layer 102 may use a multi-quantum well structure as a light source. The second type semiconductor layer 103 includes an N-type waveguide layer 1031, an N-type confinement layer 1032, and an N-type window layer 1033. The material of the P-type buffer layer 1011 may be gallium arsenide GaAs, the material of the P-type corrosion stop layer 1012 may be gallium phosphide GaP, the material of the P-type ohmic contact layer 1013 may be gallium arsenide GaAs, the materials of the P-type confinement layer 1015 and the N-type confinement layer 1032 may both be aluminum indium phosphide AlInP, the N-type window layer 1033 may be gallium phosphide GaP, and the P-type reflective layer 1014 may be an arsenide material. Specifically, a P-type buffer layer 1011, a P-type corrosion stop layer 1012, a P-type ohmic contact layer 1013, a P-type reflective layer 1014, a P-type confinement layer 1015 and a P-type waveguide layer 1016, a light-emitting layer 102, an N-type waveguide layer 1031, an N-type confinement layer 1032 and an N-type window layer 1033 can be sequentially grown on a gallium arsenide substrate. A conventional light-emitting diode epitaxial layer structure is usually first doped with an N-type doping source to form an N-type semiconductor layer, then a multi-quantum well light-emitting layer 102 is grown, and finally a P-type doping source is doped to form a P-type semiconductor layer. The N-type doping source is usually monosilane or disilane. The light-emitting diode epitaxial structure of the present application is different from the preparation method of the existing epitaxial structure. The epitaxial structure of the present application preferentially grows a P-type doped P-type semiconductor layer on a gallium arsenide substrate, and finally grows an N-type doped N-type semiconductor layer. The chip process flow can be shortened by doping reversal, and the production efficiency can be improved.

[0034] In one embodiment, the preparation process of the first type of reflective layer includes: setting the temperature of the reaction chamber to 650-670°C and the pressure to 50 mbar, respectively introducing arsine as a Group V source, hydrogen as a carrier gas, trimethylaluminum and trimethylgallium as Group III sources into the first type ohmic contact layer to form a first type of reflective layer composed of multiple substructure layers, wherein each substructure layer includes multiple groups of cycle pairs, and each group of cycle pairs is obtained by stacking a first reflective sublayer and a second reflective sublayer. Specifically, the number of substructure layers of the first type of reflective layer can be set and adjusted according to actual application requirements, and is not limited here. Taking the first type of reflective layer including three substructure layers as an example, the preparation method of the first type of reflective layer includes the following steps.

[0035] Preparation of the first substructure layer: Alternately grow the first reflective sublayer and the second reflective sublayer on a p-type GaAs substrate. The first reflective sublayer and the second reflective sublayer form a cycle pair. The first substructure layer is obtained by periodically growing multiple cycle pairs. The main process conditions are: set the temperature to 650-670°C, the chamber pressure to 50mbar, use arsine as a group V source, use hydrogen as a carrier gas, and introduce a certain amount of trimethylaluminum and trimethylgallium as group III sources. The amount of trimethylaluminum and trimethylgallium as group III sources can be adjusted according to actual component requirements and is not limited here. The growth material of the first substructure layer is AlGaAs. Specifically, the material of the first reflective sublayer is Al x1 Ga 1-x1 As, the material of the second reflective sublayer is Al x2 Ga 1-x2 As, where x1 is in the range of 0.5-0.55, and x2 is in the range of 0.9-0.95. The growth thickness of the first reflective sublayer is 45-55nm, and the growth thickness of the second reflective sublayer can also be set to 45-55nm. In the process of alternating the growth of the first reflective sublayer and the second reflective sublayer, each sublayer is doped with bismuthocene magnesium as a doping source, and the doping concentration is 9x10 17 cm -3 to 2x10 18 cm -3 , the doping element is magnesium, and the cycle pairs consisting of the first reflective sublayer and the second reflective sublayer are repeatedly grown for 3 to 8 pairs, wherein the Al component of each cycle pair in the first substructure layer is the same, that is, the proportion of Al component in each cycle pair is the same, and illustratively the proportion of Al component can be configured to be 50%, and the specific proportion of Al component can be configured and adjusted according to actual application requirements without limitation here.

[0036] Preparation of the second substructure layer: the same amount of trimethylaluminum and trimethylgallium as that used in the growth of the first substructure layer is introduced, and the first reflective sublayer and the second reflective sublayer are grown in sequence as a cycle pair. The growth thickness range of the first reflective sublayer and the second reflective sublayer of the second substructure layer is different from the growth thickness range of the first reflective sublayer and the second reflective sublayer of the first substructure layer. Specifically, the growth thickness of the first reflective sublayer and the second reflective sublayer of the second substructure layer can be set to 40-50nm. Magnesium bis(cyclopentadienyl)sulfate is also used as the doping source, the doping element is magnesium, and the doping concentration is 9x10 17 cm -3 to 2x10 18 cm -3 , the cycle pairs consisting of the first reflective sublayer and the second reflective sublayer are repeatedly grown for 3 to 8 pairs, wherein the Al component of each cycle pair in the second substructure layer is the same, that is, the proportion of Al component in each cycle pair is the same, and illustratively the proportion of Al component can be configured to be 60%, and the specific proportion of Al component can be configured and adjusted according to actual application requirements without limitation here.

[0037] Preparation of the third substructure layer: introducing the same amount of trimethylaluminum and trimethylgallium as that used in the growth of the second substructure layer, and sequentially growing the first reflective sublayer and the second reflective sublayer as a cycle pair, the growth thickness range of the first reflective sublayer and the second reflective sublayer of the third substructure layer is different from the growth thickness range of the first reflective sublayer and the second reflective sublayer of the second substructure layer, specifically, the growth thickness of the first reflective sublayer and the second reflective sublayer of the third substructure layer can be set to 35-45nm, and bismuthocene magnesium is also used as the doping source, the doping element is magnesium, and the doping concentration is 9x10 17 cm -3 to 2x10 18 cm -3 , the cycle pairs consisting of the first reflective sublayer and the second reflective sublayer are repeatedly grown 17 to 22 pairs, wherein the Al component of each cycle pair in the third substructure layer is the same, that is, the proportion of Al component in each cycle pair is the same, and illustratively the proportion of Al component can be configured to be 60%, and the specific proportion of Al component can be configured and adjusted according to actual application requirements without limitation here.

[0038] After the growth of the first substructure layer, the second substructure layer and the third substructure layer is completed, the p-type AlInP confinement layer, the P-type waveguide layer 1016 , the light-emitting layer 102 , the N-type waveguide layer 1031 , the n-type AlInP confinement layer and the N-type window layer 1033 are grown in sequence.

[0039] Based on the epitaxial structure preparation method of the embodiment of the present application, the arsenide-based P-type reflective layer 1014 replaces the traditional AlGaInP current expansion layer, which can not only play the role of current expansion, but also enhance the luminous efficiency and improve the brightness of a single light-emitting diode by reflecting the light of the multi-quantum well light source. When the brightness of a single light-emitting diode is improved, multiple light-emitting diodes are matrixed to improve the overall brightness, thereby greatly reducing the threshold of matrixing and improving production efficiency. By doping reversal, the P-type doping source is first doped and the N-type doping source is then doped, which is conducive to shortening the process flow of the chip and improving production efficiency.

[0040] See also Figure 4 , Figure 4 Schematic diagram of the structure of a light emitting diode in one embodiment of the present application. The light emitting diode includes an epitaxial structure, a first electrode 104 and a second electrode 105. The epitaxial structure includes a first type semiconductor layer 101, a light emitting layer 102 and a second type semiconductor layer 103, wherein the light emitting layer 102 can be arranged on one side of the first type semiconductor layer 101, and the second type semiconductor layer 103 can be arranged on the side of the light emitting layer 102 away from the first type semiconductor layer 101. The first type semiconductor layer 101 includes a first type ohmic contact layer and a first type reflective layer of an arsenide system, and the first type reflective layer is arranged between the first type ohmic contact layer and the light emitting layer 102, and the first type reflective layer is used to expand the current of the first type ohmic contact layer and reflect the light of the light emitting layer 102. The first electrode 104 can be electrically connected to the first type ohmic contact layer in the first type semiconductor layer 101, and the second electrode 105 can be electrically connected to the second type semiconductor layer 103.

[0041] In one embodiment, the first type may be P-type, the second type may be N-type, and the first type semiconductor layer 101 may include a P-type buffer layer 1011, a P-type corrosion stop layer 1012, a P-type ohmic contact layer 1013, a P-type reflective layer 1014, a P-type confinement layer 1015, and a P-type waveguide layer 1016 stacked in sequence. The light-emitting layer 102 may use a multi-quantum well structure as a light source. The second type semiconductor layer 103 includes an N-type waveguide layer 1031, an N-type confinement layer 1032, and an N-type window layer 1033 stacked in sequence, wherein the P-type waveguide layer 1016 and the N-type waveguide layer 1031 are respectively disposed on opposite sides of the light-emitting layer 102. The material of the P-type buffer layer 1011 can be P-type gallium arsenide, the material of the P-type corrosion stop layer 1012 can be GaP, the material of the P-type ohmic contact layer 1013 can be gallium arsenide, the material of the P-type limiting layer 1015 and the N-type limiting layer 1032 can both be aluminum indium phosphide AlInP, the N-type window layer 1033 can be gallium phosphide, and the P-type reflective layer 1014 can be an arsenide material.

[0042] In one embodiment, the first electrode 104 may be a P electrode, and the second electrode 105 may be an N electrode. The first electrode 104 is disposed on a side of the P-type ohmic contact layer 1013 away from the P-type corrosion stop layer 1012 , and the second electrode 105 is disposed on a side of the N-type window layer 1033 away from the N-type restriction layer 1032 .

[0043] The first type reflective layer may include a plurality of substructure layers, each substructure layer includes a plurality of cyclic pairs, and each cyclic pair is obtained by stacking a first reflective sublayer and a second reflective sublayer.

[0044] In one embodiment, the first type reflective layer can be divided into three groups, namely, a first substructure layer, a second substructure layer and a third substructure layer. Specifically, the three groups of substructure layers can be formed by growing aluminum gallium arsenide AlGaAs. The material of the first reflective sublayer may include Al x1 Ga 1-x1 As, the material of the second reflective sublayer includes Al x2 Ga 1-x2 As, where x1 has a value range of 0.5 to 0.55, and x2 has a value range of 0.9 to 0.95. A cycle pair can be formed by the first reflective sublayer and the second reflective sublayer, and the cycle pair can be periodically grown to obtain the first substructure layer, the second substructure layer and the third substructure layer in sequence. The growth thickness of the cycle pairs of the three substructure layers is different. The growth thickness of the first subreflective layer and the second subreflective layer of the first substructure layer is between 45nm and 55nm, the growth thickness of the first subreflective layer and the second subreflective layer of the second substructure layer is between 40nm and 50nm, and the growth thickness of the first subreflective layer and the second subreflective layer of the third substructure layer is between 35nm and 45nm. The Al component of each cycle pair in the first substructure layer, the second substructure layer and the third substructure layer is the same, that is, the proportion of the Al component in each cycle pair is the same. For example, the proportion of the Al component in the cycle pair is 40%, and the specific Al component proportion can be configured and adjusted according to actual application requirements. During the growth of the first substructure layer, the second substructure layer, and the third substructure layer, each substructure layer can be doped. The doping element of the three substructure layers can be magnesium, and the doping concentration is between 9x10 17 cm -3 to 2x10 18 cm -3. The number of cyclic pairs of the three substructure layers can also be set according to actual application requirements. For example, the first substructure layer can be formed by periodically stacking 3 to 8 pairs of cyclic pairs, the second substructure layer can also be formed by periodically stacking 3 to 8 pairs of cyclic pairs, and the third substructure layer can be formed by periodically stacking 17 to 22 pairs of cyclic pairs. Of course, the number of substructure layers in the first type of reflective layer can also be adjusted according to actual application requirements, and there is no restriction here. By designing the thickness and composition of different substructure layers in the first type of reflective layer, the reflection ability of the multi-quantum well light source can be effectively improved, thereby improving the luminous efficiency.

[0045] The above embodiments are only for explaining the principle and effect of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A light emitting diode epitaxial structure, characterized in that: include: a first type semiconductor layer; A light emitting layer, disposed on one side of the first type semiconductor layer; as well as A second type semiconductor layer is disposed on a side of the light emitting layer away from the first type semiconductor layer; Among them, the first type semiconductor layer includes a first type ohmic contact layer and a first type reflective layer of an arsenide system, and the first type reflective layer is arranged between the first type ohmic contact layer and the light-emitting layer. The first type reflective layer is used to expand the current of the first type ohmic contact layer and reflect the light of the light-emitting layer.

2. The light emitting diode epitaxial structure according to claim 1, characterized in that: The first type reflection layer includes a plurality of substructure layers, each of the substructure layers includes a plurality of cyclic pairs, and each of the cyclic pairs is obtained by stacking a first reflection sublayer and a second reflection sublayer.

3. The light emitting diode epitaxial structure according to claim 2, characterized in that: The material of the first reflective sublayer includes Al x1 Ga 1-x1 As, the material of the second reflective sublayer includes Al x2 Ga 1-x2 As, the value range of x1 is between 0.5 and 0.55, and the value range of x2 is between 0.9 and 0.

95.

4. The light emitting diode epitaxial structure according to claim 3, characterized in that: The Al composition is the same in each of the cycle pairs.

5. The light emitting diode epitaxial structure according to claim 2, characterized in that: The first type reflective layer includes a first substructure layer, a second substructure layer and a third substructure layer stacked in sequence toward the light-emitting layer, and the first substructure layer, the second substructure layer and the third substructure layer have the same doping concentration range and doping elements.

6. The light emitting diode epitaxial structure according to claim 5, characterized in that: The doping element includes magnesium, and the doping concentration range is between 9x10 17 cm -3 to 2x10 18 cm -3 The growth thickness of the first sub-reflection layer and the second sub-reflection layer of the first sub-structure layer is between 45nm and 55nm, the growth thickness of the first sub-reflection layer and the second sub-reflection layer of the second sub-structure layer is between 40nm and 50nm, and the growth thickness of the first sub-reflection layer and the second sub-reflection layer of the third sub-structure layer is between 35nm and 45nm.

7. The light emitting diode epitaxial structure according to claim 6, characterized in that: The number of cyclic pairs of the first substructure layer is between 3 and 8 pairs, the number of cyclic pairs of the second substructure layer is between 3 and 8 pairs, and the number of cyclic pairs of the third substructure layer is between 17 and 22 pairs.

8. A method for preparing a light emitting diode epitaxial structure, characterized in that: include: providing a substrate; An epitaxial structure is fabricated on the substrate, the epitaxial structure comprising: a first type semiconductor layer, the first type semiconductor layer being disposed on one side of the substrate; a light emitting layer being disposed on one side of the first type semiconductor layer; and a second type semiconductor layer being disposed on a side of the light emitting layer away from the first type semiconductor layer; wherein the first type semiconductor layer comprises a first type ohmic contact layer and a first type reflective layer formed by stacking a plurality of arsenide semiconductor layers, the first type reflective layer being disposed between the first type ohmic contact layer and the light emitting layer, and current expansion of the first type ohmic contact layer is performed through the first type reflective layer, and light of the light emitting layer is reflected.

9. The method for preparing a light emitting diode epitaxial structure according to claim 8, characterized in that: The preparation process of the first type reflective layer includes: The temperature of the reaction chamber is set to 650-670°C and the pressure is set to 50 mbar. Arsine is used as a Group V source, hydrogen is used as a carrier gas, and trimethylaluminum and trimethylgallium are used as Group III sources respectively, to form the first type of reflective layer composed of a plurality of substructure layers, wherein each of the substructure layers includes a plurality of cyclic pairs, and each group of the cyclic pairs is obtained by stacking a first reflective sublayer and a second reflective sublayer.

10. A light emitting diode, characterized in that: include: An epitaxial structure, the epitaxial structure comprising: a first type semiconductor layer; a light emitting layer, arranged on one side of the first type semiconductor layer; and a second type semiconductor layer, arranged on a side of the light emitting layer away from the first type semiconductor layer; wherein the first type semiconductor layer comprises a first type ohmic contact layer and an arsenide-based first type reflective layer, the first type reflective layer is arranged between the first type ohmic contact layer and the light emitting layer, and the first type reflective layer is used to expand the current of the first type ohmic contact layer and reflect the light of the light emitting layer; a first electrode, electrically connected to the first type ohmic contact layer; The second electrode is electrically connected to the second type semiconductor layer.

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