CN119133334A

CN119133334A - Light emitting diode and light emitting device

Info

Publication number: CN119133334A
Application number: CN202411214798.XA
Authority: CN
Inventors: 王宥楠; 张中英; 刘信佑; 赖昭序
Original assignee: Xiamen Sanan Optoelectronics Technology Co Ltd
Current assignee: Xiamen Sanan Optoelectronics Technology Co Ltd
Priority date: 2024-08-30
Filing date: 2024-08-30
Publication date: 2024-12-13

Abstract

The present application provides a light-emitting diode and a light-emitting device, the light-emitting diode includes a semiconductor stack, the semiconductor stack includes a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence; wherein the active layer is a quantum well structure, having a plurality of pairs of barrier layers and well layers arranged alternately, the barrier layers containing Al components; along the growth direction of the semiconductor stack, the average content of the Al component in at least part of the barrier layers is greater than the average content of the Al component in the next barrier layer adjacent thereto. The light-emitting diode with a variable Al component in the barrier layer provided by the present application can alleviate the drastic change of the energy band close to the P-side semiconductor layer, avoid the formation of a two-dimensional electron gas to bind the carriers, enable the holes to be smoothly injected and evenly distributed, effectively suppress the electron overflow phenomenon in the quantum well layer, and ultimately improve the carrier recombination efficiency and the luminous brightness of the product.

Description

Light emitting diode and light emitting device

Technical Field

The present application relates to the field of semiconductor manufacturing technology, and in particular, to a light emitting diode and a light emitting device.

Background

A light emitting Diode (LIGHT EMITTING Diode, LED) is a semiconductor device whose basic structure includes a PN junction between a P-type semiconductor and an N-type semiconductor, and when a forward voltage is applied to the LED, electrons and holes recombine at the junction of the PN junction to release energy, which is emitted in the form of photons, forming optical radiation.

In the prior art, an active layer of an LED is a quantum well structure, wherein a barrier layer is generally doped with an Al component so as to effectively limit the recombination luminescence of carriers in a potential well layer, generally, the Al component content is uniformly distributed or presents an increasing trend in the barrier layer of the active layer from an N-type semiconductor layer to a P-type semiconductor layer so as to reduce electron overflow, however, due to the difference of Al components of an electron blocking layer at one side of the active layer and the P-type semiconductor layer, the lattice constant mismatch between the semiconductor layers can cause the problem of stress concentration, so that a significant piezoelectric effect is generated at the interface of an electron blocking layer of the light emitting layer and the P-type semiconductor layer, the uneven distribution of carriers in the quantum well directly influences the radiation recombination process in the quantum well, the photon generation efficiency is reduced, and the overall luminescence performance is reduced.

In the process of designing and manufacturing LEDs, there is a need to provide an improved technical solution for the above-mentioned deficiencies in the prior art, so as to mitigate or eliminate the piezoelectric effect, and further improve the photoelectric conversion efficiency and/or the light-emitting brightness of the LED product.

Disclosure of Invention

In view of the above-mentioned drawbacks and disadvantages of the prior art, an object of the present application is to provide a light emitting diode and a light emitting device, which solve one or more of the above-mentioned problems.

According to an aspect of the present application, there is provided a light emitting diode comprising a semiconductor stack including a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked, wherein,

The active layer is of a quantum well structure and is provided with a plurality of pairs of barrier layers and potential well layers which are alternately arranged, the barrier layers contain Al components, and the average content of the Al components in at least part of the barrier layers is larger than that of the next barrier layer adjacent to the barrier layers along the growth direction of the semiconductor lamination.

According to an aspect of the present application, there is also provided a light emitting device including:

Packaging a substrate;

the light-emitting diode is arranged on the surface of the packaging substrate, the packaging substrate is electrically connected with the electrode structure of the light-emitting diode, and the light-emitting diode is the light-emitting diode in the technical scheme.

Compared with the prior art, the light-emitting diode and the light-emitting device provided by the application have at least the following beneficial effects:

According to the technical scheme, the average content of the Al component in the active layer is regulated and controlled to be larger than that of the next adjacent barrier layer, so that the average content of the Al component in the barrier layer in the active layer is ensured not to be reduced from P side to N side all the time, the severe change of a conductive energy band close to P side is relieved, the formation of the restraint of carrier caused by similar two-dimensional electron gas is avoided, holes can be smoothly injected in the direction of a valence band, and the hole distribution is more uniform due to the fact that the energy band piezoelectric field is relieved, in addition, the electron overflow phenomenon in the quantum well layer is effectively restrained, and the carrier concentration and the composite efficiency in the active layer are obviously improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained according to the drawings without any inventive effort for a person skilled in the art, where the positional relationship described in the drawings in the following description, unless otherwise specified, are all based on the directions in which the components are depicted in the drawings.

The thickness and size of each layer shown in the drawings can be exaggerated, omitted, or schematically drawn for convenience or clarity. In addition, the size of the light emitting diode does not completely reflect the actual size.

FIG. 1 is a graph showing the Al component content versus depth for a partial range of a prior art LED;

FIG. 2 is a schematic cross-sectional view of a light emitting diode according to an embodiment of the application;

Fig. 3 is a schematic cross-sectional view of an active layer according to an embodiment of the application;

FIG. 4 is a graph showing the Al composition content versus depth for a partial range of a light emitting diode according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a light emitting device according to an embodiment of the application.

List of reference numerals:

100. Substrate and method for manufacturing the same

210. Buffer layer

220. First semiconductor layer

230. Stress relief layer

300. Active layer

310. Barrier layer

320. Potential well layer

410. Tie layer

420. Electron blocking layer

430. Hole providing layer

440. Second semiconductor layer

500. Insulating layer

610. First electrode

620. Second electrode

10. Light emitting device

101. Packaging substrate

102. Light-emitting element

Detailed Description

In the prior art, the active layer of the LED is a quantum well structure, and the barrier layer of the LED generally has a relatively high band gap so as to effectively limit the recombination luminescence of carriers in the potential well layer, so that a certain amount of Al (such as AlGaN) is often added into the barrier layer to increase the band gap of the material. As shown in fig. 1, the position of the peak with highest Al content on the left side (peak of the first Al on the left side in the figure) is a P-type semiconductor electron blocking layer (P-EBL) which is generally doped with a large amount of Al component to suppress electron leakage and improve hole injection efficiency, and 10 peaks with Al content on the right side are 10 quantum well layers, i.e., 10 barrier layers included. The abscissa represents, from left to right, the direction from the P-type layer to the N-type layer, in which the Al content of the barrier layers of different layers is currently designed to be gradient-distributed from high to low in the direction from the P-type layer to the N-type layer in the quantum well structure, or the Al content of each barrier layer is controlled at a relatively close level to maintain the uniformity of the product, i.e., the Al composition in the barrier layer closest to the N-side is necessarily the lowest Al composition, which is excessively different from the Al composition of the P-type semiconductor electron blocking layer. The problem of stress concentration caused by lattice constant mismatch between the semiconductor layers cannot be relieved by the design, a remarkable piezoelectric effect exists at the interface of the light-emitting layer and the electron blocking layer of the P-type semiconductor layer, the carrier in the quantum well is unevenly distributed, the radiation recombination process in the quantum well is directly influenced, the photon generation efficiency is reduced, and the overall light-emitting performance is reduced.

Based on the background technology and the technical defects, the application provides a light-emitting diode, which comprises a semiconductor lamination layer, wherein the semiconductor lamination layer comprises a first semiconductor layer, an active layer and a second semiconductor layer which are sequentially laminated,

The active layer is of a quantum well structure and is provided with a plurality of pairs of barrier layers and potential well layers which are alternately arranged, the barrier layers contain Al components, and the average content of the Al components in at least part of the barrier layers is larger than the average content of the Al components in the next adjacent barrier layers along the growth direction of the semiconductor lamination, namely the direction from the first semiconductor layer (N-type layer) to the second semiconductor layer (P-type layer).

According to the technical scheme, according to the direction from the first semiconductor layer to the second semiconductor layer, the average content of Al components in at least part of barrier layers is larger than that of the next barrier layer adjacent to the first semiconductor layer, so that the situation that the Al components of barrier layers of different layers are always reduced or invariable is avoided, the piezoelectric effect is formed between the active layer and the electron barrier layer on the P side is reduced, carriers can be more uniformly distributed in the quantum well, and the carrier recombination efficiency is further improved.

In some embodiments, the average Al component content in each of the barrier layers is greater than the average Al component content in the next barrier layer adjacent thereto along the growth direction of the semiconductor stack. And gradient gradual change exists in the Al components from the barrier layers of the first pair of quantum well structures to the barrier layers of the last pair in the active layer, so that the distribution of the Al components is optimized, and the piezoelectric effect is further improved.

In some embodiments, the active layer comprises a quantum well structure with 2-20 periods alternately arranged, the material of the barrier layer comprises Al _x1In_y1Ga_1-x1-y1 N, and the material of the potential well layer comprises Al _x2In_y2Ga_1-x2-y2 N, wherein 0-x 2< x 1-1, and 0-y 1< y 2-1. By setting proper quantum well cycle number to obtain better threshold current, the quaternary material precisely controls the energy band gaps of the barrier layer and the potential well layer, thereby optimizing the energy band structure and the carrier transmission characteristic of the device.

In some embodiments, the Al component content at any position inside each barrier layer is 80% -120% of the average value of the Al component content of the barrier layer. The relatively uniformly distributed Al component in each layer helps to form a stable energy band structure, improves the distribution of carriers in the quantum well layer, and also helps to reduce lattice defects and impurities in the barrier layer and improve the crystal growth quality of the active layer.

In some embodiments, the average Al composition differences of adjacent barrier layers are equal or unequal along the growth direction of the semiconductor stack, i.e., the Al composition changes of adjacent barrier layers may be uniform or non-uniform. On the premise of keeping the overall gradual change trend of the Al component in the active layer, the gradual change mode and the gradual change degree can be optimized according to requirements, and the carrier distribution condition in the active layer is further improved.

In some embodiments, the barrier layers have opposite lower and upper surfaces along a growth direction of the semiconductor stack, each barrier layer having a starting content and a terminating content of an Al component from the lower surface to the upper surface, wherein the terminating content is less than the starting content and the terminating content of each barrier layer is greater than or equal to the starting content of the next barrier layer adjacent thereto. The method is favorable for forming smooth energy band transition between adjacent layers, reduces energy band discontinuity at an interface, reduces scattering and recombination loss of carriers at the interface, reduces lattice stress accumulation caused by abrupt change of Al components, and improves long-term stability and reliability of the device.

In some embodiments, the barrier layer of the active layer has an Al component content of between 30% -0%.

In some embodiments, the barrier layer of the active layer has an Al component content of between 5×10 ¹⁹atom/cm³ to 0. The component content range can provide a certain band gap width without excessively affecting the mobility of carriers and the reliability of the device.

In some embodiments, the barrier layer has a thickness betweenBetween them. The proper thickness enables formation of a sufficient barrier height, prevents carriers from leaking from the quantum well layer to the barrier layer or other region, and avoids interlayer or intra-layer stress concentration problems.

In some embodiments, the barrier layers are each equal or unequal in thickness. The thickness of some barrier layers may be adjusted separately for different types of semiconductor devices to achieve better performance of the product.

In some embodiments, a stress relief layer is further included, the stress relief layer being located between the first semiconductor layer and the active layer.

In some embodiments, an electron blocking layer is further included, the electron blocking layer being located between the active layer and the second semiconductor layer. By restricting the flow of electrons from the active layer to the P-type semiconductor layer, electron overflow is reduced to thereby improve carrier recombination efficiency.

In the above embodiment, the method further includes a bonding layer between the active layer and the electron blocking layer.

In some embodiments, the semiconductor stack has a first mesa exposing the first semiconductor layer, the semiconductor stack adjacent to the first mesa forming a light emitting mesa, further comprising:

An insulating layer located above and on the side wall of the semiconductor stack, the insulating layer having a through hole penetrating to the light emitting mesa of the first semiconductor layer and the first mesa of the second semiconductor layer, respectively;

And the pad electrode comprises a first electrode and a second electrode, the first electrode and the first semiconductor layer are in electrical contact, and the second electrode and the second semiconductor layer are in electrical contact.

In some embodiments, the wavelength of the light emitted by the light emitting diode is 400 nm-760 nm. The technical scheme is particularly suitable for white light and blue-green light emitting diodes.

The present application also provides a light emitting device including:

Packaging a substrate;

The LED is arranged on the surface of the packaging substrate, the packaging substrate is electrically connected with the electrode structure of the LED, and the LED is any one of the LED in the technical scheme. The light-emitting device comprises the light-emitting diode, so that the light-emitting device has good photoelectric conversion efficiency and light-emitting brightness.

The composition of each layer and dopant contained in the light emitting diode of the present application may be analyzed in any suitable manner, such as secondary ion mass spectrometry (secondary ion mass spectrometer, SIMS). The thickness of each layer included in the light emitting diode of the present application may be analyzed in any suitable manner, such as a Transmission Electron Microscope (TEM) or Scanning Electron Microscope (SEM), for example, to match the depth position of each layer on a SIMS map.

Further advantages and effects of the present application will become apparent to those skilled in the art from the disclosure of the present application, which is described by the following specific examples. The application may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present application. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.

For convenience of description, the growth direction of the semiconductor stack is defined as upper and the opposite direction is defined as lower, i.e., the growth direction of the semiconductor stack is the direction from the first semiconductor layer (i.e., N-type layer) to the second semiconductor layer (P-type layer).

As shown in fig. 2 to 3, the present embodiment provides a light emitting diode, which includes a semiconductor stack formed on a substrate 100, and the semiconductor stack includes at least a first semiconductor layer 220, an active layer 300, and a second semiconductor layer 440 sequentially stacked.

The substrate 100 is a transparent substrate including a sapphire substrate, a silicon carbide substrate, a silicon substrate, a gallium nitride substrate, an aluminum nitride substrate, or the like, and has a thickness ranging from 500 μm to 2000 μm. As an example, the substrate 100 is a sapphire substrate, which helps to improve the light efficiency and luminous intensity of the blue-green or white LEDs. In some embodiments, the substrate 100 may also be a patterned sapphire substrate.

With continued reference to fig. 2 to 3, the n-side semiconductor layer may be provided in a multilayer structure composed of a nitride semiconductor such as GaN, inGaN, alGaN. The N-side semiconductor layer includes a buffer layer 210, a first semiconductor layer 220, and a stress release layer 230 sequentially stacked on the substrate 100. The N-side semiconductor layer may be provided with other layers than the above layers, or may be partially omitted, as required.

In some embodiments, a buffer layer 210 is formed over the substrate 100, the buffer layer 210 being located between the substrate 100 and the first semiconductor layer 220. The buffer layer 210 is an n-type material layer made of a GaN-based group III-V nitride semiconductor, or an undoped material layer, such as an unintentionally doped GaN layer (undroped GaN, u-GaN), to relieve stress due to lattice constant mismatch between the substrate 100 and the first semiconductor layer 220, and to optimize the process for better formation of a semiconductor stack over the substrate 100.

In some embodiments, the first semiconductor layer 220 is formed over the buffer layer 210 as an N-type semiconductor layer for providing electrons, and the N-type doped nitride layer in the first semiconductor layer 220 may include one or more N-type impurities of group IV elements, which may include one or a combination of Si, ge, and Sn.

In some embodiments, a stress relief layer 230 is formed on the first semiconductor layer 220, the stress relief layer 230 is located between the first semiconductor layer 220 and the active layer 300, and has a thickness betweenThe stress relief layer 230 contains an In component, such as InGaN, to reduce lattice defects due to lattice constant mismatch, effectively transfer the lattice constant from the first semiconductor layer 220 to the InGaN quantum well layer In the active layer 300, improve interface flatness of the active layer 300, reduce V-bits generation, and provide a better growth environment for the quantum well layer, thereby improving crystal quality of the active layer 300.

In some embodiments, the active layer 300 is formed on the stress releasing layer 230, the active layer 300 is in a quantum well structure, and has a plurality of pairs of barrier layers 310 and potential well layers 320 which are alternately arranged, the barrier layers 310 contain Al components, the materials of the barrier layers comprise Al _x1In_y1Ga_1-x1-y1 N, the materials of the potential well layers comprise Al _x2In_y2Ga_1-x2-y2 N, wherein x2 is more than or equal to 0 and less than or equal to 1, y1 is more than or equal to 0 and less than or equal to 1, and a proper quantum well cycle number is set to obtain a better threshold current, and the quaternary material precisely controls the energy band gaps of the barrier layers and the potential well layers, so that the energy band structure and the carrier transmission characteristics of the device are optimized. The barrier layer 310 may be a nitride semiconductor having an In content lower than the potential well layer 320 but an Al content higher than the potential well layer 320, such as AlInGaN or AlGaN. If the potential well layer 320 and the barrier layer 310 are alternately stacked, the first and last layers may be well layers or barrier layers.

Along the growth direction of the semiconductor stack, at least part of the barrier layer 310 has an average Al component content greater than the average Al component content in the next barrier layer 310 adjacent thereto. That is, for the active layer 300 having the two pairs of quantum well structures, the Al composition content of the barrier layer 310 near the N side is greater than that of the barrier layer 310 near the P side, so that the Al content in the barrier layer 310 near the P side semiconductor layer is lower than that of the layer in the existing product, to reduce the composition difference between the active layer 300 and the P side electron blocking layer 420, reduce the piezoelectric effect between the active layer 300 and the electron blocking layer 420, and improve the product performance stability. For quantum well structures having more than two pairs, the Al composition of a portion of the barrier layer 310 may be selectively set to a graded profile from high to low.

Table 1 is a design of Al composition distribution for a barrier layer provided in this embodiment, the barrier layer 310 is defined as a first barrier layer, a second barrier layer. Correspondingly, the potential well layer 320 is defined as a first well layer, a second well layer. As an example, the active layer of the product provided in this embodiment has 10 pairs of quantum wells, namely ten barrier layers, the Al component content in the barrier layers is between 20% and 30%, the Al components in the first to fifth barrier layers are uniformly distributed, the Al component content in the first to fifth barrier layers is 30%, the Al doping concentration is 5×10 ¹⁹atom/cm³, the Al component content in the sixth to tenth barrier layers is 20%, the Al doping concentration is 3.3×10 ¹⁹atom/cm³, and the Al components in the latter five barrier layers are uniformly distributed and are lower than the Al component content of the former five barrier layers. Compared with the high Al content of the first five layers, the Al content of the last five layers, especially the last barrier layer, close to the P-type semiconductor layer is reduced, the composition difference between the layer and the P-side electron blocking layer 420 is reduced, the interlayer piezoelectric effect is correspondingly reduced, and the product stability is improved.

TABLE 1 parameter Table of the Al component content and doping concentration of the barrier layer in sample one

Barrier layer number	Content of Al component (%)	Al doping concentration (E19)
			1	30	5
2	30	5
			3	30	5
4	30	5
			5	30	5
6	20	3.3
			7	20	3.3
8	20	3.3
			9	20	3.3
10	20	3.3

In an alternative embodiment, the Al composition content of the first barrier layer close to the N-side semiconductor layer is the layer with the highest Al composition content of all barrier layers 310 in the active layer 300, and the Al content decreases sequentially from the second barrier layer until the i-th barrier layer, i < k, and the Al composition content from the i+1th barrier layer to the k-th barrier layer remains unchanged. In an alternative embodiment, the Al component content of the barrier layers close to the N-side semiconductor layer is the same and is the layer with the highest Al component content of all barrier layers 310 in the active layer 300, and the Al content decreases from one barrier layer to the kth barrier layer in sequence.

In an alternative embodiment, some barrier layers are arranged in groups with a decreasing content or a leveling content, so as to realize that the overall Al content of the active layer 300 shows a decreasing trend from high to low, and ensure that the Al content of the last barrier layer near the P-side semiconductor layer is the lowest value of the barrier layer 310 in the active layer 300.

In an alternative embodiment, the Al component content at any location inside each barrier layer 310 is 80% -120% of the average value of the Al component content in the barrier layer 310, so as to maintain a relatively constant Al component content, thereby forming a relatively stable energy band structure and reducing crystal defects of the active layer 300. In an alternative embodiment, the specific difference of the Al content in each barrier layer 310 is not limited to the gradual trend from high to low, but may be in the form of low to high, high to low, or multiple doping peaks or in the form of irregular component distribution, so that any position in each barrier layer 310 has an Al component content 80% -120% of the average Al component content in the barrier layer 310, which is not described herein.

In some embodiments, the average Al component content in each barrier layer is greater than the average Al component content in the next barrier layer adjacent thereto along the growth direction of the semiconductor stack. That is, the Al content in the barrier layer of the active layer is designed to be a trend of gradually decreasing from the N side to the P side, the Al content in the barrier layer near the P side semiconductor layer is lowest, and gradually increasing near the N side to alleviate the drastic change of the conductive energy band near the P side, avoid the formation of a two-dimensional-like electron gas to bind carriers, and holes can be smoothly injected in the valence band direction, and the hole distribution is more uniform because the energy band piezoelectric field is alleviated.

In some embodiments, the average content difference of the Al components of the adjacent barrier layers 310 is equal or different along the growth direction of the semiconductor stack, and the gradual change mode and the gradual change degree are optimized on the premise of keeping the overall gradual change trend of the Al components of the barrier layers 310 in the active layer 300, so as to further improve the carrier distribution situation in the active layer. That is, the Al content gradient trend of the barrier layer 310 in the active layer 300 may be an equal difference decrease or a non-equal difference decrease, for example, the Al content difference in the several barrier layers 310 near the N-side or P-side semiconductor layer may be lower than the Al content difference in the several barrier layers 310 in the middle of the active layer 300. When the Al content in the adjacent barrier layers is designed to be gradually changed from high to low, the Al content of the i-th barrier layer is [ x-x (i-1)/(k-1) ]%, x is the maximum value of the Al content, and k is the number of cycles of the barrier layer 310.

Along the growth direction of the semiconductor stack, the barrier layers 310 have opposite lower and upper surfaces, from the lower surface to the upper surface, each barrier layer 310 has an initial content and a final content of an Al component, and at the final content of each barrier layer 310, the content of each barrier layer is greater than or equal to the initial content of the next barrier layer 310 adjacent thereto, the above component distribution helps to form a smooth energy band transition between adjacent layers, and reduces energy band discontinuity at the interface, thereby reducing scattering and recombination loss of carriers at the interface, reducing lattice stress accumulation due to abrupt Al component, and improving long-term stability and reliability of the device.

In some embodiments, the active layer 300 includes quantum well structures with 2-20 periods alternately arranged, and the Al component content in the barrier layer 310 is at a maximum of 30%, i.e., the maximum initial content is 30%, and the minimum value is 0, i.e., the minimum end content is 0. As an example, the start content and the end content of the barrier layer 310 may be 30% and 5%, or 25% and 10%, or 20% and 10%, or 15% and 10%, respectively, and so on. It can be appreciated that when the initial content of the barrier layer 310 is less than 20%, the termination content thereof should not be too low, so that the occurrence of insufficient barrier height is avoided, and carrier leakage cannot be effectively prevented, thereby reducing the internal quantum efficiency of the LED, for example, the termination content of the barrier layer 310 may be within a range of 5% -15%, so as to ensure that the total amount of Al elements in the whole active layer 300 is suitable. It is understood that when the initial content of the barrier layer 310 is higher than 20%, the termination content thereof may be correspondingly reduced until the last barrier layer is not doped with Al component, so as to reduce lattice mismatch and stress concentration between layers, or reduce defect or impurity concentration, thereby avoiding the problem of crystal quality degradation, for example, the termination content of the barrier layer 310 may be within a range of 0-15%.

In an alternative embodiment, the Al content in the barrier layers 310 is between 30% and 0%, and the Al content between adjacent barrier layers 310 is equal and decreasing, i.e. uniformly varies. As an example, the Al content of the first barrier layer is 30% and the Al content of the k barrier layer is 0 (k=20), the Al content in the adjacent barrier layers is designed in a gradual progression from high to low, the Al content of the second barrier layer is [ 30-30/(20-1) ]2% = 28.4%, the Al content of the third barrier layer is 26.8%, and so on until the Al content of the last barrier layer decreases to 0.

Table 2 shows the Al composition distribution design of the barrier layer provided in this embodiment, and it can be seen that the active layer of the product provided in the following table has 10 pairs of quantum wells, and comprises 10 barrier layers, wherein the Al composition content in the barrier layers is between 3% and 30%, and the doping concentration is between 0.5X10 ¹⁹atom/cm³～5×10¹⁹atom/cm³. The Al component content of the first barrier layer is 30%, the Al doping concentration is 5 multiplied by 10 ¹⁹atom/cm³, the Al content is uniformly decreased from the first barrier layer, so that carriers can be more uniformly distributed in the quantum well until the Al component content of the tenth barrier layer is reduced to 3%, and the Al doping concentration is reduced to 0.5 multiplied by 10 ¹⁹atom/cm³. The distribution of Al components of the barrier layer which is uniformly decreased can relieve the severe change of the conductive energy band near the P-type semiconductor layer, avoid the formation of a similar two-dimensional electron gas to bind carriers, enable holes to be smoothly injected into the active layer to be composited with electrons, and enable the hole distribution to be more uniform because the energy band piezoelectric field is relieved.

TABLE 2 parameter Table of the Al component content and doping concentration of the barrier layer in sample two

Barrier layer number	Content of Al component (%)	Al doping concentration (E19)
			1	30	5
2	27	4.5
			3	24	4
4	21	3.5
			5	18	3
6	15	2.5
			7	12	2
8	9	1.5
			9	6	1
10	3	0.5

In an alternative embodiment, the Al content in the barrier layer 310 is between 30% and 0%, and the Al content in the barrier layer 310 tends to decrease in a non-equal difference. As an example, the Al content range of the first barrier layer may be any one of [30%,25% ], the Al content range of the second barrier layer may be any one of [25%,20% ]. Further, the Al component content of the different barrier layers 310 is adjusted according to the thickness of the layers, the thickness of the barrier layers 310 is betweenIn between, a lower Al content parameter may be provided for a relatively thicker barrier layer 310, and a higher Al content parameter may be provided for a relatively thinner barrier layer 310 to meet the forbidden bandwidth requirement, thereby providing an effective barrier effect.

Table 3 shows the Al composition distribution design of the barrier layer provided in this embodiment, and it can be seen that the active layer of the product provided in the following table has 10 barrier layers, the Al composition content in the barrier layers is between 0% and 30%, and the doping concentration is between 0% and 5×10 ¹⁹atom/cm³. The Al component content of the first barrier layer is 30%, the Al doping concentration is 5×10 ¹⁹atom/cm³, and the Al content is unevenly decreased from the first barrier layer until the Al component content of the tenth barrier layer is reduced to 0. Through tests, the sample III with the non-uniform decreasing Al component in the barrier layer has better photoelectric performance, and the luminous brightness is obviously improved compared with the prior product.

TABLE 3 parameter Table of the Al component content and doping concentration of the barrier layer in sample III

Barrier layer number	Content of Al component (%)	Al doping concentration (E19)
			1	30	5
2	25	4.17
			3	22	3.67
4	18	3
			5	17	2.83
6	15	2.5
			7	12	2
8	9	1.5
			9	5	0.83
10	0	0

Further, the active layer 300 includes quantum well structures with 4-16 periods alternately arranged, and as an example, the number of periods of the quantum well structures of the active layer may be 6, 8, 10, 12 or 14, and quantum well layer designs with different structures are selected according to different device performance requirements. Fig. 4 shows an ion concentration curve of a quantum well structure with 10 periods alternately arranged, the first peak on the left is a P-type electron blocking layer, the S1 segment is a thickness region where the active layer 300 is located, the Al content is between 5×10 ¹⁸atom/cm³～1×10¹⁹atom/cm³, the Al content in each adjacent barrier layer 310 is nearly equal and decreasing, compared with a comparative sample with the same average Al content, the light emitting efficiency of the product shown in fig. 4 is improved from 1.752 to 1.841, the brightness improvement can reach 5.08%, and the operating voltage is uniform through testing.

In an alternative embodiment, the content of the Al component in the barrier layer 310 is between 5×10 ¹⁹atom/cm³ to 0. Corresponding to the content parameter of the Al component in the barrier layer 310 between 30% and 0%, the description thereof will be omitted.

In an alternative embodiment, the thicknesses of the barrier layers in the active layer 300 may be the same or different, and the thicknesses of the well layers may be the same or different, and the thicknesses of some barrier layers 310 may be independently adjusted for different types of semiconductor devices to obtain product performance with better performance. According to the thickness difference of different barrier layers 310 and potential well layers 320, the content of Al components in the corresponding layers is further adjusted to achieve better carrier recombination efficiency and light-emitting brightness.

It is to be understood that, in the active layer 300 of the multiple quantum well structure, the barrier layers in the two well layers are not particularly limited to 1 layer (well layer/barrier layer/well layer), and different barrier layers such as a multi-layer composition impurity amount may be provided in such a manner that 2 or more barrier layers are well layer/barrier layer a/barrier layer b/. Degree./well layer, and the Al composition in the continuous barrier layers in contact is set to decrease from high to low, respectively, while the Al content design scheme in the above embodiment is still followed for the design of the continuous barrier layers. Referring to fig. 4, the number of well layers is 10, and the number of barrier layers is 10 in this embodiment, but the present invention is not limited thereto. For example, the number of well layers may be increased to 12 layers or reduced to a smaller number of layers, for example, 8 layers instead of 10 layers, and the number of barrier layers may be increased to 16 layers or reduced to a smaller number of layers, for example, 4 layers instead of 10 layers.

In some embodiments, the average Al component content in each barrier layer 310 is greater than the average Al component content in the next barrier layer 310 adjacent thereto along the growth direction of the semiconductor stack. That is, in order to make the active layer 300 have a decreasing trend of the overall Al content with the Al composition inside each barrier layer 310 kept constant, the Al content at any point in the i-th barrier layer is greater than or equal to the Al content in the i+1th barrier layer. The uniformly distributed Al composition within each layer helps to form a stable energy band structure, improves the distribution of carriers within the quantum well layer, and also helps to reduce lattice defects and impurities in the barrier layer 310, improving the overall crystal growth quality of the active layer 300.

The barrier layers 310 have opposite lower and upper surfaces along the growth direction of the semiconductor stack, each barrier layer 310 has an initial content and a termination content of an Al component from the lower surface to the upper surface, wherein the termination content of each layer is smaller than the initial content of the layer, that is, the Al component content in each barrier layer 310 also keeps a decreasing trend from high to low, and the termination content of each barrier layer 310 is greater than or equal to the initial content of the next barrier layer 310 adjacent thereto. For example, for a quantum well structure with 20 periods, the Al composition in barrier layers 310 is between 30% -0%, the Al composition between adjacent barrier layers 310 and within each barrier layer 310 is uniformly varied, the Al content of the first barrier layer gradually decreases from 30% to 28.4%, the Al content of the second barrier layer gradually decreases from 28.4% to 26.8%, and so on until the Al content of the last barrier layer decreases to 0.

Table 4 shows the design of the Al composition of the first barrier layer of the barrier layer according to the present embodiment, the first barrier layer thickness of the sample isThe initial content of the Al component of the first barrier layer is 30%, the doping concentration is 5 multiplied by 10 ¹⁹atom/cm³, the final content of the Al component of the first barrier layer is 25%, and the doping concentration is 4.17 multiplied by 10 ¹⁹atom/cm³. Inside the first barrier layer, the Al component is distributed in a decreasing manner from bottom to top. The initial content of the Al component of the second barrier layer is less than or equal to 25%, and the concentration of each barrier layer from the second barrier layer to the last barrier layer is gradually changed, so that smoother energy band transition is formed, and the long-term stability and reliability of the device are improved.

TABLE 4 parameter Table of the Al component content and doping concentration of the first barrier layer of the barrier layer in sample four

Depth of	Content of Al component (%)	Al doping concentration (E19)
			0	30	5
10	29	4.83
			20	28	4.67
30	27	4.5
			40	26	4.33
50	25	4.17

In the above embodiment, the thicknesses of the barrier layers 310 may be the same or different, for example, they are allOr may be provided in other thicknesses as desired,Or alternativelyIn an alternative embodiment, the thickness of the barrier layer 310 near the N-side semiconductor layer is smaller, so that electrons are injected effectively, and the rate of change of the Al composition in the layer is different for the barrier layers 310 with different thicknesses, but the range of change of the Al composition in the layer, that is, the difference of the Al composition in the layer is still the same. In an alternative embodiment, to ensure the band continuity at the interface and the crystal quality at the interface, the rate of change of the Al component content in the barrier layer 310 with different thicknesses is kept the same, the element content is changed with the change of the thickness, and the difference between the initial content and the termination content of the Al component in the barrier layer 310 with different thicknesses is different, but the composition and the structural stability of the barrier layer 310 can be improved.

In some embodiments, the barrier layer 310 has a thickness betweenIn between, a suitable thickness can form a sufficient barrier height, prevent carriers from leaking from the quantum well layer to other regions, and avoid interlayer or intra-layer stress concentration problems. In an alternative embodiment, the thickness of each barrier layer 310 is the same to optimize the process. In an alternative embodiment, the thickness of each barrier layer 310 may also be partially different, for example, the barrier layer 310 near the N-side semiconductor layer is relatively thinner, the thicknesses of several barrier layers located in the middle of the active layer 300 are the same, the barrier layer 310 located near the P-side semiconductor layer is relatively thicker, and for thinner barrier layers 310, the content of Al components in the layer should be relatively smaller or be uniformly distributed, so as to reduce the process difficulty and improve the distribution accuracy of Al components. It can be appreciated that the thickness of the barrier layer 310 at different positions can be designed independently according to the actual requirement, and the Al component content thereof can also be designed independently according to the actual thickness, which is not shown here. Further, the barrier layer 310 has a thickness betweenBetween them.

In some embodiments, the P-side semiconductor layer is formed over the active layer 300, and may Be formed in a single-layer or multi-layer structure formed of a nitride semiconductor layer containing P-type impurities such as Mg, zn, be, and the like. The P-side semiconductor layer includes a junction layer 410, an electron blocking layer 420, a hole providing layer 430, and a second semiconductor layer 440, which are sequentially stacked. The P-side semiconductor layer may be formed by other layers than the above layers, and a part of the layers may be omitted.

In some embodiments, the junction layer 410 is first formed on the active layer 300, where the junction layer 410 is located between the active layer 300 and the electron blocking layer 420, and is made of AlGaN or GaN, so that the P-side semiconductor layer grows well on the active layer 300, and structure and quality defects caused by lattice mismatch between layers are reduced, and by adjusting doping elements and doping concentration, the energy band structure can be adjusted, so that energy level matching is better achieved, and thus, the recombination efficiency and the light emitting performance of carriers are improved.

In some embodiments, an electron blocking layer 420 is first formed on the junction layer 410, to confine electrons in the active layer 300, and prevent electrons from overflowing, and the component may be P-doped AlGaN.

In some embodiments, a hole providing layer 430 and a second semiconductor layer 440 are formed on the electron blocking layer 420, the hole providing layer 430 is used to inject holes into the active layer 300, so as to reduce the recombination loss of electrons and holes in the transmission process, improve the carrier recombination efficiency, and the Al component content of the hole providing layer 430 is lower than the average Al component content of the barrier layer 310, and the second semiconductor layer 440 may be p-GaN.

The light emitting diode provided by the application further comprises an electrode structure, specifically, the semiconductor lamination is provided with a first table top exposing the N side semiconductor layer, the semiconductor lamination adjacent to the first table top forms a light emitting table top, and the light emitting diode further comprises:

an insulating layer 500 located above and on the side wall of the semiconductor stack, the insulating layer 500 having a through hole penetrating to the first mesa of the N-side semiconductor layer and the light emitting mesa of the P-side semiconductor layer, respectively;

The pad electrode, including a first electrode 610 and a second electrode 620, is positioned over the insulating layer 500 and fills the through holes, respectively, the first electrode 610 makes electrical contact with the first semiconductor layer 220, and the second electrode 620 makes electrical contact with the second semiconductor layer 440.

The wavelength of the radiation light of the light emitting diode provided by the embodiment is 400-760 nm, and the light emitting diode is particularly suitable for white light and blue-green light emitting diodes.

The embodiment also provides a light-emitting device 10, referring to fig. 5, the light-emitting device 10 includes a package substrate 101, at least one light-emitting diode disposed on a surface of the package substrate 101, and the package substrate 101 is electrically connected with an electrode structure of the light-emitting diode. The light emitting element 102 may be a light emitting diode provided in the above embodiment of the present application, and the light emitting diode is electrically connected to the package substrate 101 through the first electrode 610 and the second electrode 620. The light-emitting device 10 thus has good light-emitting brightness and good quality reliability as the light-emitting diode.

In summary, the light emitting diode and the light emitting device provided by the application effectively overcome various defects in the prior art and have high industrial utilization value.

The above embodiments are merely illustrative of the principles of the present application and its effectiveness, and are not intended to limit the application. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the application. Accordingly, it is intended that all equivalent modifications and variations of the application be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. A light emitting diode is characterized by comprising a semiconductor lamination layer, wherein the semiconductor lamination layer comprises a first semiconductor layer, an active layer and a second semiconductor layer which are sequentially laminated,

2. The light-emitting diode according to claim 1, wherein an average Al component content in each of the barrier layers is larger than an average Al component content in a next one of the barrier layers adjacent thereto in a growth direction of the semiconductor stack.

3. The light-emitting diode according to claim 1, wherein the active layer comprises a quantum well structure with 2 to 20 periods alternately arranged, the material of the barrier layer comprises Al _x1In_y1Ga_1-x1-y1 N, and the material of the potential well layer comprises Al _x2In_y2Ga_1-x2-y2 N, wherein 0.ltoreq.x2 < x1.ltoreq.1, 0.ltoreq.y1 < y2.ltoreq.1.

4. The led of claim 1, wherein the Al composition content at any location within each barrier layer is 80% -120% of the average Al composition content of the barrier layer.

5. The light-emitting diode according to claim 1, wherein the average Al component content difference between adjacent barrier layers is equal or unequal along the growth direction of the semiconductor stack.

6. The led of claim 1, wherein each barrier layer has a starting content and a terminating content of an Al composition from the lower surface to the upper surface along a growth direction of the semiconductor stack, wherein the terminating content is less than the starting content and the terminating content of each barrier layer is greater than or equal to the starting content of a next barrier layer adjacent thereto.

7. The light-emitting diode according to claim 1, wherein an Al component content in the barrier layer of the active layer is between 30% and 0%.

8. The light-emitting diode according to claim 1, wherein the Al component content in the barrier layer of the active layer is between 5 x 10 ¹⁹atom/cm³ to 0.

9. The led of claim 1, wherein the barrier layer has a thickness between Between them.

10. The light emitting diode of claim 1, wherein each barrier layer has an equal or unequal thickness.

11. The light emitting diode of claim 1, further comprising a stress relief layer between the first semiconductor layer and the active layer.

12. The light emitting diode of claim 1, further comprising an electron blocking layer positioned between the active layer and the second semiconductor layer.

13. The light emitting diode of claim 12, further comprising a tie layer between the active layer and the electron blocking layer.

14. The light emitting diode of claim 1, wherein the semiconductor stack has a first mesa exposing the first semiconductor layer, the semiconductor stack adjacent to the first mesa forming a light emitting mesa, further comprising:

an insulating layer located above and on the side wall of the semiconductor stack, the insulating layer having a through hole penetrating to the first mesa of the first semiconductor layer and the light-emitting mesa of the second semiconductor layer, respectively;

15. A light emitting device, the light emitting device comprising:

Packaging a substrate;

at least one light emitting diode arranged on the surface of the packaging substrate, wherein the packaging substrate is electrically connected with the electrode structure of the light emitting diode, and the light emitting diode is the light emitting diode according to any one of claims 1-14.