CN113394319B - Deep ultraviolet light-emitting element and preparation method thereof - Google Patents

Abstract

The invention provides a deep ultraviolet light-emitting element and a preparation method thereof, wherein the deep ultraviolet light-emitting element comprises: the epitaxial layer comprises a substrate and an epitaxial layer located on the substrate, wherein the epitaxial layer sequentially comprises from bottom to top: the quantum well structure comprises a first n-type semiconductor layer, a blocking layer, a quantum well layer and a P-type semiconductor layer, wherein the blocking layer comprises at least two hole blocking layers and a second n-type semiconductor layer between every two adjacent hole blocking layers. According to the invention, the blocking layer is additionally arranged between the first n-type semiconductor layer and the quantum well layer, so that the distribution of electron and hole wave functions in the quantum well layer can be regulated and controlled, the diffusion transition of a p-type hole to the first n-type semiconductor layer is reduced, meanwhile, the concentration difference degree of the electron and the hole of the quantum well layer can be reduced, the overlapping and recombination probability of the electron wave functions of the electron and the hole in the quantum well layer is improved, the quantum conversion efficiency of the deep ultraviolet light-emitting element is further improved, and the light-emitting efficiency of the deep ultraviolet light-emitting element is improved to 5% -10%.

Description

Deep ultraviolet light-emitting element and preparation method thereof

technical field

The invention relates to the technical field of semiconductor chips, in particular to a deep ultraviolet light-emitting element and a preparation method thereof.

Background technique

The deep ultraviolet light-emitting element has a wavelength range of 200nm to 300nm. The deep ultraviolet light emitted can interrupt the DNA or RNA of viruses and bacteria, and directly kill viruses and bacteria. It can be widely used in air purification, tap water sterilization, household air conditioning sterilization, Auto air conditioner sterilization and other sterilization fields.

The p-type semiconductor layer of the deep ultraviolet light emitting element uses AlGaN with high Al composition. As the Al composition increases, the doping and ionization efficiency of Mg decreases, resulting in the hole concentration of the deep ultraviolet light emitting element generally lower than 1E17cm ^-2 , while the n-type semiconductor layer is doped with Si, the doping and ionization efficiency of Si are high, and the electron concentration is generally higher than 5E18cm ^-2 . Due to the large difference in the concentration of holes and electrons between the p-type semiconductor layer and the n-type semiconductor layer, the concentration of electrons injected into the quantum well layer is much higher than the hole concentration, which in turn leads to the spatial distribution of the electron-hole wave function in the quantum well layer. Very inconsistent, the electron-hole recombination efficiency is low. In the case of large current injection, the excess electrons will overflow the quantum well layer and leak to the p-type semiconductor layer, and then generate non-radiative recombination with holes, further causing a sharp drop in luminous efficiency. Therefore, the large concentration difference and uneven distribution of electrons and holes in deep ultraviolet light-emitting elements are the important reasons for their luminous efficiency generally lower than 5%.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a deep ultraviolet light emitting element and a preparation method thereof, so as to solve the problems of large concentration difference and uneven distribution of electrons and holes in the deep ultraviolet light emitting element.

In order to achieve the above object and other related objects, the present invention provides a deep ultraviolet light-emitting element, comprising: a substrate and an epitaxial layer on the substrate, the epitaxial layer sequentially including from bottom to top: a first n-type semiconductor layer, blocking layer, quantum well layer and p-type semiconductor layer, wherein the blocking layer includes at least two hole blocking layers and a second n-type semiconductor layer between every two adjacent hole blocking layers.

Optionally, in the deep ultraviolet light emitting element, the blocking layer is a sandwich structure layer, which includes a stacked first hole blocking layer, a second n-type semiconductor layer and a second hole blocking layer.

Optionally, in the deep ultraviolet light-emitting element, the thickness of the first hole blocking layer is

Optionally, in the deep ultraviolet light-emitting element, the thickness of the second hole blocking layer is

Optionally, in the deep ultraviolet light-emitting element, the thickness of the second n-type semiconductor layer is 50 nm˜200 nm.

Optionally, in the deep ultraviolet light emitting element, the material of the hole blocking layer is at least one of AlGaN and AlN.

Optionally, in the deep ultraviolet light-emitting element, the content of the Al component in the material of the hole blocking layer is greater than 90%.

Optionally, in the deep ultraviolet light-emitting element, the material of the second n-type semiconductor layer includes AlGaN.

Optionally, in the deep ultraviolet light emitting element, the Al component content in the material of the second n-type semiconductor layer is the same as that of the first n-type semiconductor layer.

Optionally, in the deep ultraviolet light-emitting element, the Al component content in the material of the second n-type semiconductor layer is 50% to 75%.

Optionally, in the deep ultraviolet light emitting element, the material of the first n-type semiconductor layer is doped with Si, and the Si doping concentration is 8E18cm ⁻³ to 5E19cm ⁻³ .

Optionally, in the deep ultraviolet light-emitting element, the second n-type semiconductor layer is doped with Si, and the Si doping concentration in the second n-type semiconductor layer is the first n-type The Si doping concentration of the semiconductor layer is 1.6% to 62.5%.

Optionally, in the deep ultraviolet light emitting element, the Si doping concentration in the material of the second n-type semiconductor layer is 8E17cm ^-3 to 5E18cm ^-3 .

Optionally, in the deep ultraviolet light-emitting element, the p-type semiconductor layer includes a p-type electron blocking layer and a p-type contact layer on the p-type electron blocking layer.

Optionally, in the deep ultraviolet light-emitting element, the material of the p-type electron blocking layer includes AlGaN.

Optionally, in the deep ultraviolet light-emitting element, the material of the p-type contact layer includes at least one of AlGaN and GaN.

Optionally, in the deep ultraviolet light-emitting element, the epitaxial layer further includes an AlN layer located between the substrate and the first n-type semiconductor layer.

In order to achieve the above purpose and other related purposes, the present invention also provides a preparation method of a deep ultraviolet light-emitting element, including:

providing a substrate;

An epitaxial layer is formed on the substrate, and the epitaxial layer includes, from bottom to top, a first n-type semiconductor layer, a blocking layer, a quantum well layer and a p-type semiconductor layer, wherein the blocking layer includes at least two empty layers A hole blocking layer and a second n-type semiconductor layer between every two adjacent hole blocking layers.

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the blocking layer is a sandwich structure layer, which includes a stacked first hole blocking layer, a second n-type semiconductor layer and a second hole blocking layer. .

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the thickness of the first hole blocking layer is

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the thickness of the second hole blocking layer is

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the thickness of the second n-type semiconductor layer is 50 nm˜200 nm.

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the material of the hole blocking layer is at least one of AlGaN and AlN.

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the content of the Al component in the material of the hole blocking layer is greater than 90%.

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the material of the second n-type semiconductor layer includes AlGaN.

Optionally, in the preparation method of the deep ultraviolet light emitting element, the content of the Al component in the material of the second n-type semiconductor layer is the same as that of the first n-type semiconductor layer.

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the content of the Al component in the material of the second n-type semiconductor layer is 50% to 75%.

Optionally, in the preparation method of the deep ultraviolet light emitting element, the material of the first n-type semiconductor layer is doped with Si, and the Si doping concentration is 8E18cm ^-3 to 5E19cm ^-3 .

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the second n-type semiconductor layer is doped with Si, and the Si doping concentration in the second n-type semiconductor layer is the same as that of the first n-type semiconductor layer. The Si doping concentration of an n-type semiconductor layer is 1.6% to 62.5%.

Optionally, in the preparation method of the deep ultraviolet light emitting element, the Si doping concentration in the material of the second n-type semiconductor layer is 8E17cm ^-3 to 5E18cm ^-3 .

Optionally, in the method for preparing a deep ultraviolet light-emitting element, the p-type semiconductor layer includes a p-type electron blocking layer and a p-type contact layer on the p-type electron blocking layer.

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the material of the p-type electron blocking layer includes AlGaN.

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the material of the p-type contact layer includes at least one of AlGaN and GaN.

Optionally, in the method for preparing a deep ultraviolet light-emitting element, the epitaxial layer further includes an AlN layer located between the substrate and the first n-type semiconductor layer.

Optionally, in the preparation method of the deep ultraviolet light-emitting element, the process of forming the first n-type semiconductor layer, blocking layer, quantum well layer and p-type semiconductor layer is MOCVD process, molecular beam epitaxy process, HVPE process. process, plasma-assisted chemical vapor deposition, and sputtering.

Compared with the prior art, the technical scheme of the present invention has the following beneficial effects:

In the present invention, by adding a blocking layer between the first n-type semiconductor layer and the quantum well layer, the distribution of the wave function of electron holes in the quantum well layer can be regulated, and the diffusion transition of p-type holes to the first n-type semiconductor layer can be reduced. At the same time, the blocking layer forms a high electron barrier, which can reduce the injection efficiency of electrons into the quantum well layer, reduce the difference between electrons and holes in the quantum well layer, and improve the electron wave function of electrons and holes in the quantum well layer. The probability of overlap and recombination is improved, thereby improving the quantum conversion efficiency of the deep-ultraviolet light-emitting element, so that the light-emitting efficiency of the deep-violet light-emitting element is increased to 5% to 10%.

Description of drawings

1 is a schematic structural diagram of an ultraviolet semiconductor light-emitting element according to an embodiment of the present invention;

2 is a flow chart of a method for preparing an ultraviolet semiconductor light-emitting element according to an embodiment of the present invention;

Among them, in Figure 1 to Figure 2:

100-substrate, 101-first n-type semiconductor layer, 102-blocking layer, 1021-first hole blocking layer, 1022-second n-type semiconductor layer, 1023-second hole blocking layer, 103-quantum well layer, 104-p-type semiconductor layer, 1041-p-type electron blocking layer, 1042-p-type contact layer, 105-AlN layer.

Detailed ways

The concentration of holes and electrons in the p-type semiconductor layer and the n-type semiconductor layer in the deep ultraviolet light-emitting element in the prior art are quite different, resulting in that the concentration of electrons injected into the quantum well layer is much higher than the concentration of holes, which in turn leads to electron holes. The spatial distribution of the wave function in the quantum well layer is extremely inconsistent, and the electron-hole recombination efficiency is low. In the case of high current injection, the excess electrons will overflow the quantum well layer, leak into the p-type semiconductor layer, and generate non-radiative recombination with holes, further causing a sharp drop in luminous efficiency. Therefore, the large concentration difference and uneven distribution of electrons and holes in deep ultraviolet light-emitting elements are the important reasons for their luminous efficiency generally lower than 5%.

In order to solve the problems of large concentration difference and uneven distribution of electrons and holes in the ultraviolet semiconductor light-emitting element, the present invention provides an ultraviolet semiconductor light-emitting element, by adding a hole blocking layer between the first n-type semiconductor layer and the quantum well layer , which can reduce the diffusion transition of p-type holes to the first n-type semiconductor layer. At the same time, the formation of a high electron barrier can reduce the injection efficiency of electrons into the quantum well layer and reduce the concentration difference between electrons and holes in the quantum well layer. The overlapping recombination probability of the electron wave functions of electrons and holes in the quantum well layer is improved, thereby improving the quantum conversion efficiency of the deep ultraviolet semiconductor light-emitting element.

Before describing the embodiment according to the present invention, the following will be described in advance. First of all, in this specification, the Al composition ratio is not explicitly given, and when it is only marked as "AlGaN", it means that the chemical composition ratio of group III elements (the sum of Al and Ga) and N is 1:1, and the group III elements Al and An arbitrary compound in which the ratio of Ga is not fixed. In addition, when only marked with "AlN" or "GaN", it means that Ga and Al are not included in the composition ratio, respectively, but only marked with "AlGaN" does not exclude either AlN or GaN. It should be noted that the value of the Al composition ratio can be measured by photoluminescence measurement, X-ray diffraction measurement, or the like.

In addition, in this specification, the layer which functions as a p-type electrically is called a p-type layer, and the layer which functions as an n-type electrically is called an n-type layer. On the other hand, when specific impurities such as Mg and Si are not intentionally added and do not function as p-type or n-type electrically, it is referred to as "i-type" or "undoped". The undoped layer can be mixed with unavoidable impurities during the manufacturing process. Specifically, when the carrier density is small (for example, less than 4×10/cm), it is referred to as “undoped layer” in this specification. ". In addition, the value of the impurity concentration, such as Mg and Si, was obtained by SIMS analysis.

The deep ultraviolet light-emitting element and its preparation method proposed by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that, the accompanying drawings are all in a very simplified form and in inaccurate scales, and are only used to facilitate and clearly assist the purpose of explaining the embodiments of the present invention.

Referring to FIG. 1 , the deep ultraviolet light emitting element provided in this embodiment includes: a substrate 100 and an epitaxial layer located on the substrate 100 , and the epitaxial layer sequentially includes: a first n-type semiconductor layer 101 , a blocking layer from bottom to top 102 , a quantum well layer 103 and a P-type semiconductor layer 104 . The blocking layer 102 includes at least two hole blocking layers and a second n-type semiconductor layer between every two adjacent hole blocking layers.

As the substrate 100, a substrate capable of transmitting light emitted from the quantum well layer 103 and emitting deep ultraviolet light from the substrate side is preferably used, and, for example, a sapphire substrate, a single crystal AlN substrate, or the like can be used. In addition, as the substrate 100, an AlN template substrate in which an undoped AlN structure layer is epitaxially grown on the surface of a sapphire substrate can also be used. In order to improve the light extraction efficiency, the light exit side of the substrate 100 or the opposite side thereof, or the surface of the AlN structure layer of the AlN template substrate may be in a concave-convex shape. In order to reduce the dislocation of the AlN structure layer, a high temperature (for example, 1500° C. or higher) annealing treatment may be performed.

An AlN layer 105 may be disposed between the substrate 100 and the first n-type semiconductor layer 101 . The AlN layer 105 can serve as a buffer layer for alleviating the lattice mismatch between the substrate 100 and the first n-type semiconductor layer 101 . Of course, the AlN layer 105 can also be used as an unintentional doping layer or the like.

The first n-type semiconductor layer 101 is disposed on the substrate 100 through the AlN layer 105 as required, or the first n-type semiconductor layer 101 may be disposed directly on the substrate 100 . The first n-type semiconductor layer 101 may be a conventional n-type layer, for example, may be composed of n-AlGaN. The first n-type semiconductor layer 101 functions as an n-type layer by doping an n-type dopant. Specific examples of the n-type dopant include silicon (Si), germanium (Ge), Tin (Sn), sulfur (S), oxygen (O), titanium (Ti), zirconium (Zr), etc., but not limited thereto. The dopant concentration of the n-type dopant may be a dopant concentration at which the first n-type semiconductor layer 101 can function as an n-type layer. Further, the n-type dopant in the first n-type semiconductor layer 101 is preferably Si, and the doping concentration of Si is preferably 8E18cm ^-3 to 5E19cm ^-3 . In addition, the band gap of the first n-type semiconductor layer 101 is preferably wider than that of the quantum well layer 103 (well layer in the case of a multi-quantum well structure), and is transparent to emitted deep ultraviolet light. In addition, the first n-type semiconductor layer 101 may have a superlattice structure in addition to a single-layer structure or a structure composed of multiple layers.

The blocking layer 102 includes at least two hole blocking layers and a second n-type semiconductor layer between every two adjacent hole blocking layers. The blocking layer 102 may include two spatial blocking layers and one second n-type semiconductor layer, or may include three spatial blocking layers and two second n-type semiconductor layers. For example, the blocking layer 102 sequentially includes a first hole blocking layer, a second n-type semiconductor layer, and a second hole blocking layer; for another example, the blocking layer 102 sequentially includes a first hole blocking layer, a second n-type semiconductor layer, and a second hole blocking layer. type semiconductor layer, second hole blocking layer, second n-type semiconductor layer, first hole blocking layer. The first hole blocking layer and the second hole blocking layer may be completely identical or not identical, for example, at least one of parameters such as material, Al composition content and thickness are different. Of course, the blocking layer 102 may also include four or five spatial blocking layers, and the like, and the second n-type semiconductor layer is also increased accordingly, which will not be repeated here.

Preferably, the blocking layer 102 is a sandwich structure, including a first hole blocking layer 1021 , a second n-type semiconductor layer 1022 and a second hole blocking layer 1023 stacked in sequence, please refer to FIG. 1 . The following embodiments are described in detail by taking the blocking layer 102 as a sandwich structure as an example.

The blocking layer 102 includes a first hole blocking layer 1021 , a second n-type semiconductor layer 1022 and a second hole blocking layer 1023 stacked on the first n-type semiconductor layer 101 . The material of the first hole blocking layer 1021 and the second hole blocking layer 1023 can be at least one of AlGaN and AlN, that is, the material of the first hole blocking layer 1021 can be the same as the material of the second hole blocking layer 1021. The hole blocking layers 1023 are the same or different. For example, the material of the first hole blocking layer 1021 is AlGaN, and the material of the second hole blocking layer 1023 is AlN. The Al content in the material of the first hole blocking layer 1021 and the second hole blocking layer 1023 is greater than 90%, and the material of the first hole blocking layer 1021 and the second hole blocking layer 1023 The content of Al components in can be the same or different. For example, the materials of the first hole blocking layer 1021 and the second hole blocking layer 1023 are both AlGaN, and the Al composition content is 95%. For another example, the material of the first hole blocking layer 1021 is AlGaN, and the Al composition content is 95%, and the material of the second hole blocking layer 1023 is AlN.

Since the first hole blocking layer 1021 and the second hole blocking layer 1023 are structural layers with high Al composition and have relatively high electron potential barriers, electrons in the first n-type semiconductor layer 101 enter the quantum wells The layer 103 requires more energy, therefore, the first hole blocking layer 1021 and the second hole blocking layer 1023 can reduce the injection efficiency of electrons into the quantum well layer 103 . Moreover, it can be known from the Boltzmann distribution or Dirac distribution that the holes have a probability to transition to the first n-type semiconductor layer 101, and the first hole blocking layer 1021, the second n-type semiconductor layer 1022 and the second The sandwich structure composed of the hole blocking layer 1023 can reduce the diffusion transition of p-type holes to the first n-type semiconductor layer 101 through high potential barrier and energy band regulation, thereby increasing the injection efficiency of p-type holes. According to the above analysis, the blocking layer 102 , namely the sandwich structure composed of the first hole blocking layer 1021 , the second n-type semiconductor layer 1022 and the second hole blocking layer 1023 can reduce the interaction between electrons and holes in the quantum well layer 103 The degree of concentration difference and the problem of uneven distribution.

所述第二空穴阻拦层1023的厚度(设计值)优选为

Since AlGaN is a high resistance material, the higher the Al composition, the higher the electron ionization energy, the higher the resistance value and the higher the voltage, so the thickness of the first hole blocking layer 1021 and the second hole blocking layer 1023 cannot be If the thickness is too thick, the design value cannot be exceeded, otherwise, the resistance value rises sharply and the voltage rises due to the thickness of the first hole blocking layer 1021 and/or the second hole blocking layer 1023 being too thick. The thickness (design value) of the first hole blocking layer 1021 is preferably

The thickness (design value) of the second hole blocking layer 1023 is preferably

The second n-type semiconductor layer 1022 is used to control the concentration of electrons injected into the quantum well layer 103 and the current spreading. The material of the second n-type semiconductor layer 1022 includes AlGaN, but is not limited thereto. The Al composition content in the material of the second n-type semiconductor layer 1022 may be the same as or different from that of the first n-type semiconductor layer 101 . Preferably, the Al content in the material of the second n-type semiconductor layer 1022 is the same as that of the first n-type semiconductor layer 101 . The content of the Al component in the material of the second n-type semiconductor layer 1022 is preferably 50% to 75%. The second n-type semiconductor layer 1022 is doped with an n-type dopant, and the n-type dopant may be silicon (Si), germanium (Ge), tin (Sn), sulfur (S), Oxygen (O), titanium (Ti), zirconium (Zr), etc., but not limited thereto. Further, the n-type dopant is preferably Si, and the Si doping concentration in the second n-type semiconductor layer 1022 is much lower than the Si doping concentration in the first n-type semiconductor layer 101 to achieve The effect of controlling the concentration of electrons injected into the quantum well layer 103 and improving the lateral current spreading of the first n-type AlGaN layer 101 . Further, the Si doping concentration in the second n-type semiconductor layer 1022 is 1.6%˜62.5% of the Si doping concentration in the first n-type semiconductor layer 101 . Preferably, the Si doping concentration in the material of the second n-type semiconductor layer 1022 is 8E17cm ⁻³ to 5E18cm ⁻³ . The thickness of the second n-type semiconductor layer 1022 is preferably 50 nm˜200 nm.

The quantum well layer 103 is disposed on the blocking layer 102 . The quantum well layer 103 may have a single-layer structure, preferably a multiple quantum well (MQW: Multiple Quantum Well) structure formed by repeating well layers and barrier layers composed of AlGaN having different Al composition ratios. It should be noted that, in the case of the single-layer structure, the layer that emits deep ultraviolet light is the quantum well layer itself, and in the case of the multi-quantum well structure, the layer that emits deep ultraviolet light is the well layer. The quantum well layer 103 is a conventional structure, and details are not described here.

The p-type semiconductor layer 104 disposed on the quantum well layer 103 may include a p-type electron blocking layer 1041 and a p-type contact layer 1042 . The p-type electron blocking layer 1041 is used for blocking electrons, preventing electrons from overflowing into the p-type contact layer 1042, and then injecting electrons into the quantum well layer 103, so as to reduce the occurrence of non-radiative recombination and further improve the performance of the deep ultraviolet light-emitting element. Luminous efficiency.

The material of the p-type electron blocking layer 1041 is preferably AlGaN, but not limited thereto. The thickness of the p-type electron blocking layer 1041 is not particularly limited. It should be noted that the thickness of the p-type electron blocking layer 1041 is preferably thicker than the thickness of the barrier layer. In addition, magnesium (Mg), zinc (Zn), calcium (Ca), beryllium (Be), manganese (Mn), etc. are exemplified as the p-type dopant to be doped into the p-type electron blocking layer 1041, but Not limited to this. The p-type dopant is preferably Mg. The dopant concentration of the p-type electron blocking layer 1041 is not particularly limited as long as it can function as a p-type semiconductor layer.

The p-type contact layer 1042 is disposed on the p-type electron blocking layer 1041 . The p-type contact layer 1042 is a layer for reducing the contact resistance between the p-side electrode provided directly above and the p-type electron blocking layer 1041 . The material of the p-type contact layer 1042 includes at least one of AlGaN and GaN, but is not limited thereto. As the p-type contact layer of the deep ultraviolet light-emitting element, a p-type GaN layer that is easy to increase the hole concentration is generally used, and a p-type AlGaN layer can also be used. Although the hole concentration of the AlGaN layer may be slightly lower than that of the GaN layer, but Since the deep ultraviolet light emitted from the light emitting layer can pass through the p-type AlGaN layer, the light extraction efficiency of the entire deep ultraviolet light emitting element can be improved, and the light emission output of the deep ultraviolet light emitting element can be improved.

Compared with the existing deep ultraviolet light-emitting element, this embodiment has a blocking layer between the first n-type semiconductor layer and the quantum well layer. This structure can control the distribution of the electron-hole wave function in the quantum well layer, and can reduce the p-type Holes diffuse and transition to the first n-type semiconductor layer, and at the same time, the blocking layer structure forms a high electron barrier, which can reduce the injection efficiency of electrons into the quantum well layer, reduce the difference between electrons and holes in the quantum well layer, and improve the quantum well layer. The overlap and recombination probability of the electron wave functions of electrons and holes in the layer ultimately improve the quantum conversion efficiency of the deep ultraviolet light-emitting element, and increase the luminous efficiency of the deep ultraviolet light-emitting element to 5% to 10%.

In addition, the present invention also provides a preparation method of the above-mentioned deep ultraviolet light-emitting element, which specifically includes:

Step S0: providing a substrate;

Step S1 : forming an epitaxial layer on the substrate, the epitaxial layer sequentially includes from bottom to top: a first n-type semiconductor layer, a blocking layer, a quantum well layer and a p-type semiconductor layer, wherein the blocking layer includes at least Two hole blocking layers and a second n-type semiconductor layer between every two adjacent hole blocking layers.

Preferably, the blocking layer is a sandwich structure, comprising a first hole blocking layer, a second n-type semiconductor layer and a second hole blocking layer stacked in sequence.

A buffer layer may also be provided between the substrate and the first n-type semiconductor layer for relaxing the lattice mismatch between the substrate and the first n-type semiconductor layer. As the buffer layer, an undoped group III nitride semiconductor layer such as an AlN layer can be used.

The p-type semiconductor layer includes a p-type electron blocking layer and a p-type contact layer. The p-type electron blocking layer is used to block electrons. contact resistance between the electron blocking layers.

Referring to FIG. 2, the formation process of the epitaxial layer specifically includes:

Step S11: forming a buffer layer on the substrate;

Step S12: forming a first n-type semiconductor layer on the buffer layer;

Step S13: forming a blocking layer on the first n-type semiconductor layer;

Step S14: forming a quantum well layer on the blocking layer;

Step S15: forming a p-type semiconductor layer on the quantum well layer.

In the step S13, when the blocking layer is a sandwich structure including a first hole blocking layer, a second n-type semiconductor layer and a second hole blocking layer stacked in sequence, the first n-type semiconductor The specific process of forming the blocking layer includes:

Step S131: forming a first hole blocking layer on the first n-type semiconductor layer;

Step S132: forming a second n-type semiconductor layer on the first hole blocking layer;

Step S133 : forming a second hole blocking layer on the second n-type semiconductor layer.

It should be noted that, in the above preparation method, metal organic vapor deposition (MOCVD: MetAlOrganicChemicAl Vapor Deposition) method, molecular beam epitaxy (MBE:Molecular Beam Epitaxy) method, HVPE (Hydride Vapor Phase Epitaxy, hydride vapor phase epitaxy) method can be used ) method, plasma-assisted chemical vapor deposition (plasmachemic Al vapor deposition, PCVD), sputtering method and other known thin film growth methods to form the deep ultraviolet light-emitting element, for example, the buffer layer, the first n-type semiconductor can be formed by MOCVD method layer, a first hole blocking layer, a second n-type semiconductor layer, a second hole blocking layer, a quantum well layer, and a p-type semiconductor layer.

Compared with the existing technical solutions of deep ultraviolet light-emitting elements, the present invention sets a blocking layer structure between the first n-type semiconductor layer and the quantum well layer, which can regulate the distribution of the electron-hole wave function in the quantum well layer, and can Reduce the diffusion transition of p-type holes to the first n-type semiconductor layer, and at the same time, the blocking layer structure forms a high electron barrier, which can reduce the injection efficiency of electrons into the quantum well layer and reduce the concentration difference between electrons and holes in the quantum well layer. It can improve the overlap and recombination probability of the electron wave functions of electrons and holes in the quantum well layer, and finally improve the quantum conversion efficiency of the deep ultraviolet light emitting element, and improve the luminous efficiency of the deep ultraviolet light emitting element to 5% to 10%.

In addition, it should be understood that, although the present invention has been disclosed above with preferred embodiments, the above embodiments are not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, many possible changes and modifications can be made to the technical solution of the present invention by using the technical content disclosed above, or modified into equivalents of equivalent changes Example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention still fall within the protection scope of the technical solutions of the present invention.

It is also to be understood that this invention is not limited to the particular methods, compounds, materials, fabrication techniques, uses and applications described herein, which may vary. It should also be understood that the terminology described herein is used to describe particular embodiments only, and not to limit the scope of the present invention. It must be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a step" means a reference to one or more steps, and possibly including sub-steps. All conjunctions used should be understood in their broadest sense. Accordingly, the word "or" should be understood to have the definition of logical "or" rather than the definition of logical "exclusive or" unless the context clearly dictates otherwise. A structure described herein is to be understood to also refer to functional equivalents of the structure. Language that can be interpreted as approximate should be understood as such, unless the context clearly dictates otherwise.

Claims (29)

1. A deep ultraviolet light emitting element, comprising: the epitaxial layer comprises a substrate and an epitaxial layer located on the substrate, wherein the epitaxial layer sequentially comprises from bottom to top: the light-emitting diode comprises a first n-type semiconductor layer, blocking layers, a quantum well layer and a P-type semiconductor layer, wherein the blocking layers comprise at least two hole blocking layers and a second n-type semiconductor layer between every two adjacent hole blocking layers, the second n-type semiconductor layer is doped with Si, the Si doping concentration of the second n-type semiconductor layer is 1.6% -62.5% of the Si doping concentration of the first n-type semiconductor layer, the Al component content of the material of the hole blocking layers is larger than 90%, and the Al component content of the material of the second n-type semiconductor layer is 50% -75%.

2. The deep ultraviolet light emitting device of claim 1, wherein the blocking layer is a sandwich structure layer comprising a first hole blocking layer, a second n-type semiconductor layer and a second hole blocking layer stacked one on another.

3. The deep ultraviolet light emitting element of claim 2, wherein the first hole blocking layer has a thickness of 10A-30A.

4. The deep ultraviolet light emitting element of claim 2, wherein the second hole blocking layer has a thickness of 5A-50A.

5. The deep ultraviolet light emitting element according to claim 2, wherein a thickness of the second n-type semiconductor layer is 50nm to 200 nm.

6. The deep ultraviolet light emitting element according to claim 1, wherein the hole stopper layer is made of at least one of AlGaN and AlN.

7. The deep ultraviolet light emitting element according to claim 1, wherein a material of the second n-type semiconductor layer includes AlGaN.

8. The deep ultraviolet light emitting element according to claim 7, wherein a material of the second n-type semiconductor layer has the same Al composition content as that of the first n-type semiconductor layer.

9. The deep ultraviolet light emitting device of claim 1, wherein the first n-type semiconductor layer is doped with Si, and the Si doping concentration is 8E18cm ^-3 ~5E19cm ^-3 。

10. The deep ultraviolet light emitting element according to claim 9, wherein a doping concentration of Si in a material of the second n-type semiconductor layer is 8E17cm ^-3 ~5E18cm ^-3 。

11. The deep ultraviolet light emitting element according to claim 1, wherein the P-type semiconductor layer comprises a P-type electron blocking layer and a P-type contact layer on the P-type electron blocking layer.

12. The deep ultraviolet light emitting element of claim 11, wherein the p-type electron blocking layer comprises AlGaN.

13. The deep ultraviolet light emitting element according to claim 11, wherein a material of the p-type contact layer includes at least one of AlGaN and GaN.

14. The deep ultraviolet light emitting element of claim 1, wherein the epitaxial layer further comprises an AlN layer between the substrate and the first n-type semiconductor layer.

15. A method for manufacturing a deep ultraviolet light-emitting element is characterized by comprising the following steps:

providing a substrate;

forming an epitaxial layer on the substrate, wherein the epitaxial layer sequentially comprises from bottom to top: the light-emitting diode comprises a first n-type semiconductor layer, blocking layers, a quantum well layer and a P-type semiconductor layer, wherein the blocking layers comprise at least two hole blocking layers and a second n-type semiconductor layer between every two adjacent hole blocking layers, the second n-type semiconductor layer is doped with Si, the Si doping concentration of the second n-type semiconductor layer is 1.6% -62.5% of the Si doping concentration of the first n-type semiconductor layer, the Al component content of the material of the hole blocking layers is larger than 90%, and the Al component content of the material of the second n-type semiconductor layer is 50% -75%.

16. The method according to claim 15, wherein the blocking layer is a sandwich structure layer comprising a first hole blocking layer, a second n-type semiconductor layer and a second hole blocking layer stacked one on another.

17. The method for manufacturing a deep ultraviolet light-emitting element according to claim 16, wherein the first hole blocking layer has a thickness of 10 a to 30 a.

18. The method of claim 16, wherein the second hole blocking layer has a thickness of 5A-50A.

19. The method according to claim 16, wherein the second n-type semiconductor layer has a thickness of 50nm to 200 nm.

20. The method according to claim 15, wherein the hole blocking layer is made of at least one of AlGaN and AlN.

21. The method according to claim 15, wherein the second n-type semiconductor layer is made of AlGaN.

22. The method according to claim 21, wherein a material of the second n-type semiconductor layer has the same Al composition as that of the first n-type semiconductor layer.

23. The method according to claim 15, wherein the first n-type semiconductor layer is doped with Si, and the Si doping concentration is 8E18cm ^-3 ~5E19cm ^-3 。

24. The method according to claim 23, wherein the second n-type semiconductor layer is formed with a material having a Si doping concentration of 8E17cm ^-3 ~5E18cm ^-3 。

25. The method according to claim 15, wherein the P-type semiconductor layer comprises a P-type electron blocking layer and a P-type contact layer on the P-type electron blocking layer.

26. The method according to claim 25, wherein the p-type electron blocking layer comprises AlGaN.

27. The method according to claim 25, wherein the p-type contact layer comprises at least one of AlGaN and GaN.

28. The method of claim 15, wherein the epitaxial layer further comprises an AlN layer between the substrate and the first n-type semiconductor layer.

29. The method of manufacturing the deep ultraviolet light emitting element according to claim 15, wherein a process of forming the first n-type semiconductor layer, the blocking layer, the quantum well layer, and the P-type semiconductor layer is any one of an MOCVD process, a molecular beam epitaxy process, an HVPE process, a plasma-assisted chemical vapor deposition, and a sputtering method.

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