JP7295782B2 - Ultraviolet LED and its manufacturing method - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to the technical field of semiconductor equipment, specifically to UV LEDs and manufacturing methods thereof, and more particularly to AlGaN-based UV LEDs and manufacturing methods thereof.

Group III-V semiconductor materials are widely used in the fields of light emitting lighting, solar cells, and high-power devices.In particular, wide bandgap semiconductor materials represented by gallium nitride GaN are the third generation semiconductor materials following Si and GaAs. As such, it has attracted a great deal of attention in scientific research and industry. Aluminum gallium nitride AlGaN-based light-emitting diodes (LEDs) are widely used in the fields of disinfection, phototherapy, photocuring, etc., because they can emit ultraviolet light in the wavelength range of 200-365 nm.

The structure of the most common AlGaN-based ultraviolet LED at the present stage is shown in FIG _. Ga _1-t N layer, N-type Al _w Ga _1-w N layer, Al _x Ga _1-x N/Al _y Ga _1-y N multiple quantum well layer, P-type Al _z Ga _1-z N electron barrier layer and a hole injection layer. The hole injection layer is often a P-type GaN layer, but the P-type GaN layer has a very serious absorption of ultraviolet light, limiting the extraction of ultraviolet light.

In order to avoid absorption of ultraviolet light by the hole injection layer, a high Al content AlGaN layer with an Al content of 10% or more is adopted as the hole injection layer, and an element such as Mg is doped therein. A solution has been proposed to form the P-type doping at the However, since the hole activation energy of the AlGaN layer with a high Al content is high, it is difficult to activate the doping element such as Mg to form effective holes. The external quantum efficiency of the LED is usually less than 2%, and the luminous efficiency is low. For example, the UV LED chip with the current standard size of 1 mm x 1 mm has a light emission brightness of only about 50 mW at a driving current of 350 mA. there is

SUMMARY OF THE INVENTION In view of the above defects, it is an object of the present invention to provide an ultraviolet LED with higher luminous efficiency.

Another object of the present invention is to provide a method for manufacturing an ultraviolet LED, and by adopting the manufacturing method, the obtained ultraviolet LED can have a higher luminous efficiency.

To achieve the above objects, a first aspect of the present invention provides a substrate and an undoped Al _t Ga _1-t N layer, an N-type Al _w Ga _{1- a wN} layer, an Al _x Ga _1-x N/Al _y Ga _1-y N multiple quantum well layer, an electron blocking layer and a hole injection layer, the hole injection layer comprising at least one sublayer; The sub-layers include at least two layers of a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga _1-v N layer, and a p-type GaN layer arranged in a stack, wherein 0<t<1 , 0<w<1, 0<y<x<1, 0<v≦1, 0<u≦1, u≠v.

According to the present invention, a hole injection layer with a periodic structure is adopted to form a piezoelectric polarization field, thereby reducing the hole activation energy, increasing the hole concentration, improving the electron-hole combined efficiency, Finally, it is possible to provide an ultraviolet LED that improves the internal quantum efficiency and luminous efficiency of the ultraviolet LED.

For convenience, in the present invention, the direction from the substrate to the hole injection layer is called "upward" or "upward", and conversely, the direction from the hole injection layer to the substrate is called "downward". Call it "going down". The terms “upward” and “upward” and “downward” and “downward” are only used to clearly describe the relative positional relationships between the functional layers of the UV LED.

As one preferred form of an embodiment of the present invention, each sub-layer comprises a p-type Al _v Ga _1-v N layer and a p-type GaN layer which are sequentially stacked in an upward direction from the substrate. , 0.1≦v≦1, more preferably 0.3≦v<0.9.

As another preferred form of an embodiment of the present invention, each sub-layer is sequentially stacked with a p-type Al _u Ga _1-u N layer and a p-type AL _v Ga ₁ layer in an upward direction from the substrate. 0.1≦v≦1, 0.1≦u≦1, u≠v, more preferably 0.3≦v<u _< 0.9.

As another preferred form of the embodiment of the present invention, each sub-layer is a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga ₁ layer, which is sequentially stacked in an upward direction from the substrate. _-v Including an N layer and a P-type GaN layer, 0.1 ≤ v ≤ 1, 0.1 ≤ u ≤ 1, u ≠ v, more preferably 0.3 ≤ v < 0.9, 0.3 ≤ v ≤ 0.9; 3≦u<0.9, u≠v.

The hole injection layer is formed by periodically arranging two or three of the P-type Al _u Ga _1-u N layer, the P-type Al _v Ga _1-v N layer and the P-type GaN layer. By adopting it, the formation of the piezoelectric polarization field is more favorable, the hole activation energy is reduced, the hole concentration is increased, the electron-hole combined efficiency is improved, and the internal quantum efficiency and luminous efficiency of the ultraviolet LED are further enhanced. can be improved.

Specifically, the periodic number of the hole injection layer should not exceed 100, or the number of sub-layers of the hole injection layer does not exceed 100 at most, and the sub-layers are generally 2 to 12 layers. Preferably 4 to 10 layers.

Specifically, the thickness of the P-type Al _u Ga _1-u N layer is 1 to 50 nm, preferably 1 to 10 nm, and the thickness of the P-type Al _v Ga _1-v N layer is 1 to 50 nm, preferably 1 to 10 nm, and the thickness of the P-type GaN layer is 1 to 50 nm, preferably 1 to 10 nm.

Specifically, the total thickness of the hole injection layer is generally 10-500 nm, preferably 40-120 nm, and the thickness of each sub-layer is specifically 4-50 nm, preferably 6-15 nm.

In the present invention, the doping concentration of the hole injection layer is generally controlled between 1×10 ¹⁷ and 5×10 ²⁰ cm ⁻³ and may preferably be controlled between 1×10 ¹⁸ and 1×10 ²⁰ cm ⁻³ . . For example, if Mg is employed as a doping element, the doping concentration of Mg can be controlled to 1×10 ¹⁷ to 5×10 ²⁰ cm ⁻³ , preferably 1×10 ¹⁸ to 1×10 ²⁰ cm ⁻³ .

In the present invention, the general method for forming the hole injection layer is not particularly limited, and conventional methods such as metal organic chemical vapor deposition (MOCVD) equipment, molecular beam epitaxy (MBE) equipment, One of the hydride vapor phase epitaxy (HVPE) devices and the like can be employed. In a preferred embodiment of the invention, the hole injection layer is obtained by forming one or more sublayers on the electron blocking layer and then performing an annealing, the annealing being a sequential high temperature annealing. Includes low temperature annealing. The temperature of the high temperature annealing is 850-950° C., and the time is 10 s-20 min, preferably 30 s-10 min, more preferably 30 s-5 min. The temperature of the low temperature annealing is 650-750° C., and the time is 1-60 min, preferably 2-30 min.

By adopting the annealing treatment under the above process conditions, the Mg—H bond is effectively blocked, the activation efficiency of Mg is improved, the hole concentration is increased, the electron-hole composite efficiency is improved, and finally We were able to improve the internal quantum efficiency and luminous efficiency of the ultraviolet LED.

Specifically, the above annealing treatment may be performed according to the periodic formation of the hole injection layer, the annealing treatment may be performed after the formation of each sublayer, or the annealing treatment may be performed during the formation of the sublayers. may be implemented. For example, in the upward direction from the substrate, if each sub-layer includes a p-type Al _v Ga _1-v N layer and a p-type GaN layer that are sequentially stacked, after completing the fabrication of each sub-layer, The annealing treatment can be performed, i.e. the annealing treatment can be performed after forming one p-type Al _v Ga _1-v N layer and one p-type GaN layer, or the p-type Annealing may be performed after forming the Al _v Ga _1-v N layer, and annealing may be performed again after forming the P-type GaN layer.

In the present invention, the substrate of the ultraviolet LED is not particularly limited, and may be a substrate commonly used in LEDs, such as a sapphire substrate, Si substrate, or SiC substrate.

Additionally, a buffer layer such as an AlN buffer layer, a GaN buffer layer, etc. may be additionally placed between the undoped Al _t Ga _1-tN layer and the substrate to eliminate the influence of the substrate on the epitaxy. The thickness of the buffer layer may be the usual thickness of buffer layers in current UV LEDs, such as 10-30 nm.

Furthermore, it is better to place an undoped AlN layer between the substrate and the undoped Al _{t Ga} 1 _-tN layer, such as between the buffer layer and the undoped Al t Ga _1- tN layer. The undoped AlN layer can serve as a base layer for the whole UV LED, reducing the defects forming the AlGaN material on the substrate, and finally improving the internal quantum efficiency of the UV LED. In embodiments of the present invention, the thickness of the undoped AlN layer may be controlled typically between 0 and 5000 nm.

The undoped Al _t Ga _1-t N layer can act as a contact layer between the undoped AlN layer and the N-type Al _w Ga _1-w N layer to control stress and reduce dislocations. The thickness of the undoped Al _t Ga _1-tN layer may be controlled typically between 1000 and 3000 nm.

The N-type Al _w Ga _1-w N layer mainly provides electrons by doping n-type impurity atoms, for example, it can be doped with silicon atoms, and the doping concentration of silicon atoms is 1×10 ¹⁷ ~5 It may be ×10 ¹⁹ cm ⁻³ .

The Al _x Ga _1-x N/A _y Ga _1-y N multi-quantum well layers are specifically composed of alternating Al _x Ga _1-x N barrier layers and Al _y Ga _1-y N well layers. and the number of alternating installations is 2 to 50 times, such as 5 to 15 times, more preferably 6 to 12 times. and the lower layer closest to the substrate and the upper layer furthest from the substrate in the Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer are Al _x Ga _1-x N barrier layers, or Al It can be said that the _{xGa1 -} xN/ _{AlyGa1 -yN} multiple quantum well layers start with _{AlxGa1 -xN} barrier layers and end with _{AlxGa1 -xN} barrier layers.

The thickness of the Al _x Ga _1-x N barrier layer may specifically be 5-25 nm, for example 5-15 nm, and the thickness of the Al _y Ga _1-y N well layer is specifically 1-25 nm. It may be 5 nm, for example 2-3 nm.

Preferably, the Al content in the Al _y Ga _1-y N well layer is lower than the Al content in the undoped Al _t Ga _1-t N layer, ie y<t.

In this embodiment, the electron blocking layer can be the electron blocking layer structure in a normal UV LED, for example, the electron blocking layer is a P-type Al _z Ga _1-z N layer, where 0<z<1 .

Preferably, the Al content in the electron blocking layer is higher than the Al content in the hole injection layer. For example, in the upward direction from the substrate, if each sublayer in the hole injection layer includes a p-type Al _v Ga _1-v N layer and a p-type GaN layer that are stacked in sequence, then 0. 1≦v<z<1, and further, for example, a p-type Al _u Ga _1-u N layer and a p-type Al _v Ga sub-layer are sequentially stacked in an upward direction from the substrate. 0.1 ≤ v < z < 1, 0.1 ≤ u < z < 1 when including _1-v N layers, and each sub-layer is stacked in sequence, for example, in an upward direction from the substrate. 0.1≦v _< z<1 _{, 0.1 ≦} u<z<1.

Furthermore, the thickness of the p-type Al _z Ga _1-z N layer is 1-100 nm, typically 20-50 nm.

In one preferred embodiment of the present invention, the electron barrier layer is a p-type Al _r Ga _1-r N layer and a p-type Al _s Ga _1-s N layer alternately stacked, where 0<r <1, 0<s<1, r≠s, and the number of alternations is 2 to 100 times. By adopting the above Al _r Ga _1-r N layer/Al _s Ga _1-s N superlattice structure, the electron barrier layer further plays the role of an electron barrier and ultimately improves the brightness of the ultraviolet LED. can be done.

More preferably, in the upward direction from the substrate, the electron barrier layer starts with a P-type Al _r Ga _1-r N layer and ends with a P-type Al _s Ga _1-s N layer, with 0<s<r>1. , the number of alternating times is preferably 3 to 15 times, ie the electron barrier layer includes 3 to 15 p-type Al _r Ga _1-r N layers and the same number of p-type Al _s Ga _1-s N layers.

Furthermore, the Al content in the electron blocking layer is higher than the Al content in the hole injection layer, e.g. When including a P-type Al _v Ga _1-v N layer and a P-type GaN layer, 0.1≦v≦s<r<1, and further, for example, in an upward direction from the substrate, each sublayer is In the case of including the p-type Al _u Ga _1-u N layer and the p-type Al _v Ga _1-v N layer which are sequentially stacked, 0.1≦v<u≦s<r<1, and , for example, each sub-layer comprises a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga _1-v N layer, and a p-type GaN layer, which are sequentially stacked in an upward direction from the substrate. , 0.1≦v≦s<r<1, 0.1≦u≦s<r<1, u≠v.

The thickness of the p-type Al _r Ga _1-r N layer is specifically 1-100 nm, and may be 5-10 nm. The thickness of the P-type Al _s Ga _1-sN layer is specifically 1 to 100 nm, and may be 5 to 10 nm. The thicknesses of the P-type Al _r Ga _1-rN layer and the P-type Al _s Ga _1-sN layer may be the same or different.

The electron barrier layer can be doped with a P-type impurity element to form holes, such as Mg element. The doping concentration may specifically be between 1×10 ¹⁷ and 1×10 ²⁰ cm ⁻³ , preferably between 1×10 ¹⁸ and 1×10 ²⁰ cm ⁻³ .

Furthermore, the Al content in the electron barrier layer should be _higher than the Al content in the Al y Ga 1- _y N well layer in the Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer. good. For example, if the electron barrier layer is a P-type Al _z Ga _1-z N layer, 0<y<z<1. Further, for example, if the electron barrier layers are alternately stacked p-type Al _r Ga _1-r N layers and p-type Al _s Ga _1-s N layers, then 1>r>y>0 and 1 >s>y>0.

A second aspect of the present invention provides a method for manufacturing an ultraviolet LED, including the following steps.

Undoped Al _t Ga _1-t N layer, N-type Al _w Ga _1-w N layer, Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer, electron barrier layer on the substrate and a hole injection layer are sequentially formed, the hole injection layer including at least one sub-layer, the sub-layers being a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga ₁ laminated _-v includes at least two layers of an N layer and a P-type GaN layer, 0<t<1, 0<w<1, 0<y<x<1, 0<v<1, 0<u<1 , u≠v.

Specifically, an undoped Al _t Ga _1-t N layer, an N-type Al _w Ga _1-w N layer, an Al _x Ga _1-x N/Al _y Ga _1-y N multi-layer formed on the substrate. Quantum well layers, electron barrier layers, and hole injection layers are all formed by metal organic chemical vapor deposition (MOCVD) devices, molecular beam epitaxy (MBE) devices, hydride vapor phase epitaxy (HVPE) devices, and the like. It can be formed by adopting one of the process equipment commonly used in various processing processes. MOCVD technology is adopted in the specific implementation process of the present invention.

Furthermore, before forming the undoped Al _t Ga _1-tN layer on the substrate, a buffer layer may first be formed on the substrate, for example, the temperature of the reaction chamber is controlled to 600-1000° C. and the pressure is is controlled to 100 to 500 torr (760 torr=1 standard atmospheric pressure) and an aluminum source and a nitrogen gas source are injected into the reaction chamber to form an AlN buffer layer on the substrate. The thickness of the buffer layer may be the usual thickness of buffer layers in conventional UV LEDs, such as 10-30 nm.

Furthermore, before forming the undoped Al _t Ga _1-tN layer, an undoped AlN layer may first be formed over the substrate, eg, forming an AlN layer over the buffer layer. Specifically, the temperature of the reaction chamber is set to 1000-1350° C., the pressure is set to 100-400 torr, and then an aluminum source and a nitrogen gas source are injected into the reaction chamber, and hydrogen or the like is used as a carrier gas to produce undoped AlN. form a layer. The thickness of the undoped AlN layer is typically controlled between 0 and 5000 nm, and may be controlled between 500 and 5000 nm, for example.

Based on the undoped AlN layer, the temperature in the reaction chamber is controlled at 1000-1350° C., the pressure is controlled at 100-400 torr, and the reaction chamber contains gallium source, aluminum source, nitrogen gas source, and hydrogen as carrier gas. implanted to form an undoped Al _t Ga _1-tN layer on the undoped AlN layer. The thickness of the undoped Al _t Ga _1-tN layer may be controlled typically between 1000 and 3000 nm.

Based on the undoped Al _t Ga _1-t N layer, the temperature in the reaction chamber was then controlled at 1000-1350° C., the pressure was controlled at 100-400 torr, and the reaction chamber was filled with gallium source, aluminum source and nitrogen gas. source, hydrogen as a carrier gas and a silicon source can be implanted to form an N-type Al _w Ga _1-w N layer. The thickness of the N-type Al _w Ga _1-w N layer may be controlled typically between 1000 and 3000 nm, and the doping concentration of silicon atoms may be between 1×10 ¹⁷ and 5×10 ¹⁹ cm ⁻³ .

The Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer can be formed using conventional means in this technical area, for example, by controlling the temperature in the reaction chamber to 1000-1350°C. Then, the pressure is controlled to 100 to 400 torr, and a gallium source, an aluminum source, a nitrogen gas source, and hydrogen and silicon sources as carrier gases are injected into the reaction chamber to obtain an Al _x Ga _1-x N barrier layer. can. The thickness of the Al _x Ga _1-x N barrier layer may specifically be 5 to 25 nm, for example 5 to 15 nm, and the doping concentration of silicon atoms is specifically 1×10 ¹⁷ to 5 nm. It can be ×10 ¹⁹ cm ⁻³ . For the formation of the Al _y Ga _1-y N well layer, the temperature in the reaction chamber is controlled at 1000-1350° C., the pressure is controlled at 100-400 torr, and the reaction chamber contains a gallium source, an aluminum source, a nitrogen gas source, and a nitrogen gas source. An Al _y Ga _1-y N well layer can be obtained by injecting hydrogen as a carrier gas. The thickness of the Al _y Ga _1-y N well layer can be specifically set to 1 to 5 nm, and may be set to 2 to 3 nm, for example. Also, the Al content in the Al _y Ga _1-y N well layer is controlled to be lower than the Al content in the Al _x Ga _1-x N barrier layer, that is, y<x.

The Al _x Ga _1-x N barrier layers and the Al _y Ga _1-y N well layers are alternately formed as described above, and the number of alternate formations can be specifically set to 2 to 50 times. They may meet 5-15 times, or even 6-12 times. Since the Al _x Ga _1-x N/A _y Ga _1-y N multiple quantum well layers start with Al _x Ga _1-x N barrier layers and end with Al _x Ga _1-x N barrier layers, the last Al _x There is no need to dope the Ga _1-x N barrier layer with Si.

In some specific embodiments of the present invention, the step of forming an electron blocking layer specifically comprises P-type _Alz on the _{AlxGa1 -xN} / _{AlyGa1 -yN} multi-quantum well layers. Forming a Ga _1-z N layer, where 0<z<1.

For example, the temperature in the reaction chamber is controlled to 1000 to 1350° C., the pressure is controlled to 100 to 400 torr, and a gallium source, an aluminum source, a nitrogen gas source, hydrogen and magnesium sources as carrier gases are injected into the reaction chamber, A p-type Al _z Ga _1-z N layer, ie an electron blocking layer, can be obtained. The thickness of the p-type Al _z Ga _1-z N is usually 1-100 nm, preferably 20-50 nm.

In another specific embodiment of the invention, the step of forming an electron barrier layer comprises p-type Al _r Ga _1-r on the Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer. It may include alternately forming the N layer and the P-type Al _s Ga _1-s N layer, 0<r<1, 0<s<1, r≠s, and the number of times of alternately forming is 2 to 100 times. is.

For example, the temperature in the reaction chamber is controlled to 1000 to 1350° C., the pressure is controlled to 100 to 400 torr, a gallium source, an aluminum source, a nitrogen gas source, hydrogen and magnesium sources as carrier gases are injected into the reaction chamber, and P A type Al _r Ga _1-r N layer and a P-type Al _s Ga _1-s N layer can be obtained sequentially. The p-type Al _r Ga _1-r N layer and the p-type Al _s Ga _1-s N layer are alternately formed as described above, and the number of alternate formations is 2 to 100 times, preferably 3 to 15 times. Obtain an electron barrier layer.

The Al content in the P-type Al _r Ga _1-r N layer and the P-type Al _s Ga _1-s N layer are different (that is, r ≠ s), and the Al content can be controlled by changing the flow rate of the aluminum source. can be done.

The thickness of the P-type Al _r Ga _1-rN layer can be specifically 1 to 100 nm, more preferably 5 to 10 nm. The thickness of the P-type Al _s Ga _1-s N layer is Specifically, it can be 1 to 100 nm, and more preferably 5 to 10 nm. The thicknesses of the P-type Al _r Ga _1-r N layer and the P-type Al _s Ga _1-s N layer may be the same or different.

In the electron barrier layer, the Mg doping concentration can specifically be between 1×10 ¹⁷ and 1×10 20 cm ⁻³ , preferably between 1×10 ¹⁸ and 1× ^{10 20 cm −3} . The doping concentration of Mg in the P-type Al _r Ga _1-r N layer and the P-type Al _s Ga _1-s N layer may be the same or different.

As described above, the hole injection layer includes at least one sublayer, which is a stacked layer of a P-type Al _u Ga _1-u N layer, a P-type Al _v Ga _1-v N layer, At least two of the P-type GaN layers are included.

In a specific embodiment of the invention, forming the hole injection layer comprises a process of forming at least one sublayer, wherein the step of forming each sublayer specifically comprises P-type Al _v Ga _1-v It can include sequentially forming an N layer and a P-type GaN layer, where 0.1≦v<1, preferably 0.3≦v<0.9.

Specifically, the temperature of the reaction chamber is controlled at 900-1300° C., the pressure is controlled at 100-400 torr, and a gallium source, an aluminum source, a nitrogen gas source, a hydrogen source, and a magnesium source are injected into the reaction chamber, and the P-type Al _v Ga _1-v N layers can be formed. Next, the injection of the aluminum source into the reaction chamber is stopped, and the flow rates of other gallium sources, nitrogen gas sources, hydrogen sources, magnesium sources, etc. are adjusted to form a p-type GaN layer, thereby forming a sub-layer. can be formed. P-type Al _v Ga _1-v N layers and P-type GaN layers are alternately formed as described above to obtain a hole injection layer.

Alternatively, forming each sub-layer may include sequentially forming a P-type Al _u Ga _1-u N layer and a P-type Al _v Ga _1-v N layer, where 0.1≦v≦ 1, 0.1≤u≤1, u≠v, preferably 0.3≤v<u<0.9. The specific process of forming the P-type Al _u Ga _1-u N layer may refer to the above-described process of forming the P-type Al _v Ga _1-v N layer, and the description thereof is omitted here.

Alternatively, the step of forming each sub-layer may include sequentially forming a P-type Al _u Ga _1-u N layer, a P-type Al _v Ga _1-v N layer and a P-type GaN layer; 0.1≦v≦1, 0.1≦u≦1, u≠v, preferably 0.3≦v<0.9, 0.3≦u<0.9, u≠v .

Specifically, in the process of forming the hole injection layer, the Mg doping concentration can be specifically 1×10 ¹⁷ to 5×10 ²⁰ cm ⁻³ , preferably 1×10 ¹⁸ to 1×10 18 cm −3 . 10 ²⁰ cm ⁻³ .

Specifically, the periodic number of the hole injection layer should not exceed 100, or the number of sublayers of the hole injection layer should not exceed 100 at most, and the number of sublayers is usually 2 to 12, preferably is 4-10 layers.

Additionally, the process of forming the hole injection layer may include performing an anneal comprising a high temperature anneal and a low temperature anneal that are performed sequentially. The temperature of the high temperature annealing is 850-950° C., and the time is 10 s-20 min, preferably 30 s-10 min, more preferably 30 s-5 min. The temperature of the low temperature annealing is 650-750° C., and the time is 1-60 min, preferably 2-30 min.

Specifically, the annealing may be performed after the formation of each sub-layer, or may be performed during the formation of the sub-layers. For example, each sub-layer includes a P-type Al _v Ga _1-v N layer and a P-type GaN layer. After forming the P-type Al _v Ga _1-v N layer and the P-type GaN layer, The annealing treatment may be performed, that is, the annealing treatment may be performed only after forming the P-type GaN layer, or the annealing treatment may be performed after forming the P-type Al _v Ga _1-v N layer and then the P-type GaN layer. Annealing may also be performed after forming the .

In the present invention, the aluminum source, gallium source, nitrogen gas source, and the like are not particularly limited. For example, the Ga source may be trimethylgallium TMGa, the Al source may be trimethylaluminum TMAl, and the nitrogen gas source may be It may be nitrogen gas, the silicon source may be silane _SiH4 , and the magnesium source may be dicyclopentadienylmagnesium _Cp2Mg .

In addition, the method of manufacturing the ultraviolet LED may further include conventional processing such as cleaning, electrode plating, patterning, cutting, mounting, etc., all of which employ conventional steps in the conventional ultraviolet LED fabrication process. We often omit the explanation here.

The ultraviolet LED provided by the present invention adopts a hole injection layer with a periodic structure to form a piezoelectric polarization field, reduce the hole activation energy, increase the hole concentration, and combine electrons and holes. It can improve the efficiency and finally improve the internal quantum efficiency and luminous efficiency of UV LED. Further coupling of the annealing treatment performed during the hole injection layer formation process can further improve the internal quantum efficiency and luminous efficiency of the UV LED. Under the test conditions of standard ^1mm2 and applied current of 350mA, the brightness of the UV LED provided by the present invention can reach more than 80mW, and even more than 100mW, and the ordinary UV LED can achieve similar test conditions Since it far exceeds the luminous efficiency (about 50 mW) under , it can be more preferably used for sterilization, phototherapy, etc.

In the method for manufacturing an ultraviolet LED provided by the present invention, the obtained ultraviolet LED can have higher internal quantum efficiency and luminous efficiency, and the manufacturing method can be performed using conventional conventional techniques. , easy to implement and disseminate.

1 is a configuration diagram of an ultraviolet LED in the prior art; FIG. 1 is a block diagram 1 of an ultraviolet LED provided in an embodiment of the present invention; FIG. FIG. 2 is a structural diagram 2 of an ultraviolet LED provided in an embodiment of the present invention; FIG. 3 is a block diagram 3 of an ultraviolet LED provided in an embodiment of the present invention; FIG. 4 is a structural diagram 4 of an ultraviolet LED provided in an embodiment of the present invention; FIG. 5 is a structural diagram 5 of an ultraviolet LED provided in an embodiment of the present invention; FIG. 6 is a block diagram 6 of an ultraviolet LED provided in an embodiment of the present invention;

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly described below with reference to the drawings according to the embodiments of the present invention. , and fully explained. It is to be understood that the described embodiments are only some but not all embodiments of the present invention. All other embodiments obtained by persons skilled in the art without creative efforts based on the embodiments in the present invention shall fall within the protection scope of the present invention.

<Example 1>
The present embodiment provides an ultraviolet LED, the schematic diagram of which is shown in FIG. Undoped Al _t Ga _1-t N layers, N-type Al _w Ga _1-w N layers, Al _x Ga _1-x N/Al _y Ga _1-y N multiple quantum well layers, electron barrier layers, and hole injection Including layers. The hole injection layer includes at least one sub-layer, each sub-layer including a p-type Al _v Ga _1-v N layer and a p-type GaN layer stacked in an upward direction from the substrate. . 0<t<1, 0<w<1, 0<y<x<1, 0<v≦1.

The ultraviolet LED is manufactured using the MOCVD technique, and the specific steps are as follows.
(1) Raise the temperature in the reaction chamber to 900° C., control the pressure to 400 mbar, simultaneously inject trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber for about 3 min, and obtain a thickness of about 25 nm on the sapphire substrate. to form an AlN buffer layer.
(2) Raise the temperature in the reaction chamber to 1250° C., adjust the pressure to 200 mbar, and inject hydrogen, trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber for about 90 min to form an undoped AlN layer. Its thickness is about 1500 nm.
(3) Lowering the temperature in the reaction chamber to 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (100 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber for about 60 min, and An undoped Al _t Ga _1-t N layer with a thickness of about 1000 nm is formed on the doped AlN layer. t=0.52.
(4) While maintaining the temperature and pressure in the reaction chamber without changing, hydrogen, trimethylgallium (100 mL/min), trimethylaluminum (360 mL/min) and ammonia gas are injected into the reaction chamber for about 80 min to dope with silane. A single N-type Al _w Ga _1-w N layer with a thickness of about 1500 nm is formed. w=0.52 and the doping concentration of Si is 1×10 ¹⁹ cm ⁻³ .
(5) Keeping the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber for about 1 min. , silane to form an Al _x Ga _1-x N barrier layer with a thickness of about 12 nm. x=0.58 and the doping concentration of Si is 1×10 ¹⁸ cm ⁻³ .
(6) While maintaining the temperature and pressure in the reaction chamber without changing, hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas are injected into the reaction chamber for 30 s, and the thickness is about 3 nm. An Al _y Ga _1-y N well layer is formed. y=0.35%.
(7) Steps (5) and (6) are repeated for a total of 8 cycles to form a quantum well structure for 8 cycles.
(8) Keeping the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber for about 1 min. , form the last Al _x Ga _1-x N barrier layer. The thickness is about 12 nm and x=0.58.
(9) maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (250 mL/min) and ammonia gas into the reaction chamber for about 2 min; A single p-type Al _z Ga _1-z N layer doped with dicyclopentadienylmagnesium Cp ₂ Mg and having a thickness of about 30 nm is formed as an electron barrier layer. z=0.65 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(10) maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas into the reaction chamber for about 1 min; Dicyclopentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _v Ga _1-v N layer with a thickness of about 6 nm. v=0.35 and the Mg doping concentration is 2×10 ¹⁹ cm ⁻³ .
(11) The temperature in the reaction chamber is gently lowered to 1000° C., the pressure is maintained at 200 mbar, hydrogen, trimethylgallium (50 mL/min) and ammonia gas are injected into the reaction chamber for 0.5 min, and dicyclopentadienylmagnesium Dope with Cp ₂ Mg and form a single P-type GaN layer with a thickness of about 2 nm. The doping concentration of Mg is 2×10 ¹⁹ cm ⁻³ .
(12) stop injecting source materials such as hydrogen, trimethylgallium and ammonia gas into the reaction chamber, reduce the temperature in the reaction chamber to 950°C, maintain the pressure at 200 mbar, and inject nitrogen gas into the reaction chamber; , high temperature annealing. Annealing time is 2 min.
(13) Continue to lower the temperature in the reaction chamber to 750° C., maintain the pressure at 200 mbar, and then introduce nitrogen gas into the reaction chamber to perform low temperature annealing. Annealing time is 30 min.
(14) Repeat steps (10) to (13) for a total of 10 cycles to form a hole injection layer on the electron barrier layer to obtain an ultraviolet LED epitaxial wafer. The hole injection layer includes 10 sub-layers, each sub-layer including a p-type Al _v Ga _1-v N layer and a p-type GaN layer sequentially stacked upward from the substrate.

The ultraviolet LED epitaxial wafer is processed into an ultraviolet LED chip with a size of 1 mm × 1 mm, and a current of 350 mA is applied, the emission wavelength of the ultraviolet LED chip is 280 nm, the brightness is 100 mW, and the external quantum efficiency is 5%. Nearly, the positive voltage is 6.5V. The UV LED has a highly effective bactericidal action.

<Example 2>
The present embodiment provides an ultraviolet LED, the schematic diagram of which is shown in FIG. Doped Al _t Ga _1-t N layer, N-type Al _w Ga _1-w N layer, Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer, electron barrier layer and hole injection layer include.

The hole injection layer includes at least one sub-layer, each sub-layer being sequentially stacked in an upward direction from the substrate: a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga _1-v N layer and P-type GaN layer, 0<t<1, 0<w<1, 0<y<x<1, 0<v≤1, 0<u≤1, u≠v be.

The ultraviolet LED is manufactured using the MOCVD technique, and the specific steps are as follows.
(1) Raise the temperature in the MOCVD reaction chamber to 900° C., control the pressure to 400 mbar, and simultaneously inject trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber for about 1.5 min to form a thickness on the sapphire substrate. is approximately 12.5 nm.
(2) Raise the temperature in the reaction chamber to 1250° C., adjust the pressure to 200 mbar, and inject hydrogen, trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber to form an undoped AlN layer. Its thickness is 2000 nm.
(3) Lowering the temperature in the reaction chamber to 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (100 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber, and undoped AlN A single undoped Al _t Ga _1-t N layer with a thickness of about 1500 nm is formed on the layer. t=0.52.
(4) Keeping the temperature and pressure in the reaction chamber unchanged, hydrogen, trimethylgallium (90 mL/min), trimethylaluminum (360 mL/min) and ammonia gas are injected into the reaction chamber, and silane is doped to increase the thickness. A single N-type Al _w Ga _1-w N layer with a thickness of about 1000 nm is formed. w=0.47 and the doping concentration of Si is 1×10 ¹⁹ cm ⁻³ .
(5) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and adding silane. Dope to form an Al _x Ga _1-x N barrier layer with a thickness of about 12 nm. x=0.58 and the doping concentration of Si is 1×10 ¹⁸ cm ⁻³ .
(6) keeping the temperature and pressure in the reaction chamber unchanged, injecting hydrogen, trimethylgallium (50mL/min), trimethylaluminum (50mL/min) and ammonia gas into the reaction chamber, and the thickness is about 3nm; An Al _y Ga _1-y N well layer is formed. y=0.35%.
(7) Steps (5) and (6) are repeated for a total of 6 cycles to form a quantum well structure for 6 cycles.
(8) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and finally A single Al _x Ga _1-x N barrier layer is formed. Its thickness is about 12 nm and x=0.58.
(9) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (250 mL/min) and ammonia gas into the reaction chamber, A single P-type Al _z Ga _1-z N layer doped with pentadienylmagnesium Cp ₂ Mg and having a thickness of about 30 nm is formed as an electron barrier layer. z=0.65 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(10) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (100 mL/min) and ammonia gas into the reaction chamber, and dicyclo Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _u Ga _1-u N layer with a thickness of about 4 nm. u=0.45 and the doping concentration of Mg is 2×10 ¹⁹ cm ⁻³ .
(11) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _v Ga _1-v N layer with a thickness of about 6 nm. v=0.35 and the Mg doping concentration is 2×10 ¹⁹ cm ⁻³ .
(12) The temperature in the reaction chamber is gently lowered to 1000° C., the pressure is maintained at 200 mbar, hydrogen, trimethylgallium (50 mL/min) and ammonia gas are injected into the reaction chamber for about 0.5 min, and dicyclopentadienyl Dope with magnesium Cp2Mg to form a single P-type GaN layer with a thickness of about 2 nm. The doping concentration of Mg is 2×10 ¹⁹ cm ⁻³ .
(13) stop injecting hydrogen, trimethylgallium, ammonia and other source materials into the reaction chamber, reduce the temperature in the reaction chamber to 900°C, maintain the pressure at 200 mbar, and inject nitrogen gas into the reaction chamber; High temperature annealing is performed. Annealing time is 1 min.
(14) Lowering the temperature in the reaction chamber to 750° C., maintaining the pressure at 200 mbar, and then injecting nitrogen gas and performing low temperature annealing. Annealing time is 20 min.
(15) Repeat steps (10) to (14) for a total of 6 cycles to form a hole injection layer on the electron blocking layer to obtain an ultraviolet LED epitaxial wafer. The hole injection layer includes six sublayers, each sublayer being a p-type Al _u Ga _1-u N layer and a p-type Al _v Ga _1-v N layer, which are sequentially stacked upward from the substrate. layer and a P-type GaN layer.

When the ultraviolet LED epitaxial wafer is processed into an ultraviolet LED chip with a size of 1 mm ² and a current of 350 mA is applied, the emission wavelength of the ultraviolet LED chip is 280 nm, the luminance is 100 mW, and the external quantum efficiency is close to 5%, positive The voltage is 6.0V. The UV LED has a highly effective bactericidal action.

<Example 3>
This embodiment provides an ultraviolet LED, the schematic diagram of which is shown in FIG. Including Al _t Ga _1-t N layer, N-type Al _w Ga _1-w N layer, Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer, electron barrier layer and hole injection layer . The hole injection layer includes at least one sublayer, each sublayer being a p-type Al _u Ga _1-u N layer and a p-type Al _v Ga _1-v N layer stacked upward from the substrate. layer. 0<t<1, 0<w<1, 0<y<x<1, 0<v≦1, 0<u≦1, u≠v.

The UV LED is manufactured using MOCVD epitaxy technology, and the specific process steps are as follows.
(1) Raise the temperature in the reaction chamber to 950° C., control the pressure to 400 mbar, simultaneously inject trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber, and deposit a thickness of about 12.5 nm on the sapphire substrate. to form an AlN buffer layer.
(2) raising the temperature in the reaction chamber to 1250° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber to form an undoped AlN layer; The thickness is approximately 300 nm.
(3) Lowering the temperature in the reaction chamber to 1140° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (100 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber, and undoped AlN A layer of undoped Al _t Ga _1-t N with a thickness of about 1500 nm is formed on the layer. t=0.50.
(4) keeping the temperature and pressure in the reaction chamber unchanged, injecting hydrogen, trimethylgallium (90 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber, doping silane, and increasing the thickness A single N-type Al _w Ga _1-w N layer with a thickness of about 1000 nm is formed. w=0.45 and the doping concentration of Si is 1×10 ¹⁹ cm ⁻³ .
(5) maintaining the temperature in the reaction chamber at 1140° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and adding silane; Doping to form an Al _x Ga _1-x N barrier layer with a thickness of about 12 nm. x=0.55% and the doping concentration of Si is 1×10 ¹⁸ cm ⁻³ .
(6) Keeping the temperature and pressure in the reaction chamber unchanged, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas into the reaction chamber until the thickness is about 2.8 nm. Al _y Ga _1-y N well layers are formed. y=0.33%.
(7) Steps (5) and (6) are repeated for a total of 10 cycles to form a quantum well structure for 10 cycles.
(8) Maintaining the temperature in the reaction chamber at 1140° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and finally A single Al _x Ga _1-x N barrier layer is formed. The thickness is about 12 nm, x=0.55.
(9) Maintaining the temperature in the reaction chamber at 1140° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (250 mL/min) and ammonia gas into the reaction chamber, and dicyclo A single P-type Al _z Ga _1-z N layer doped with pentadienylmagnesium Cp ₂ Mg and having a thickness of about 30 nm is formed as an electron barrier layer. z=0.63 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(10) Adjust the temperature in the reaction chamber to 1150° C., maintain the pressure at 200 mbar, inject hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (100 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _u Ga _1-u N layer with a thickness of about 8 nm. u=0.45% and the Mg doping concentration is 1×10 ¹⁹ cm ⁻³ .
(11) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _v Ga _1-v N layer with a thickness of about 6 nm. v=0.35% and the Mg doping concentration is 1×10 ¹⁹ cm ⁻³ .
(12) stop injecting hydrogen, trimethylgallium, ammonia and other source materials into the reaction chamber, reduce the temperature in the reaction chamber to 950°C, maintain the pressure at 200 mbar, and inject nitrogen gas into the reaction chamber; High temperature annealing is performed. Annealing time is 3 min.
(13) The temperature in the reaction chamber is lowered to 750° C., the pressure is maintained at 200 mbar, and then nitrogen gas is injected to perform low temperature annealing. Annealing time is 25 min.
(14) Repeat steps (10) to (13) for a total of 8 cycles to form a hole injection layer on the electron blocking layer to obtain an ultraviolet LED epitaxial wafer. The hole injection layer includes eight sublayers, each sublayer being a p-type Al _u Ga _1-u N layer and a p-type Al _v Ga _1-v N layer sequentially stacked upward from the substrate. layer.

The UV LED epitaxial wafer is processed into a UV LED chip with a size of 1 mm ² , and a current of 350 mA is applied, the emission wavelength of the UV LED chip is 280 nm, the brightness is 110 mW, and the positive voltage is 6.0V. The UV LED has a highly effective bactericidal action.

<Example 4>
This embodiment provides an ultraviolet LED, the schematic diagram of which is shown in FIG. Including Al _t Ga _1-t N layer, N-type Al _w Ga _1-w N layer, Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer, electron barrier layer and hole injection layer . The hole-injection layer includes at least one sub-layer, each sub-layer including a p-type Al _v Ga _1-v N layer and a p-type GaN layer, which are stacked upward from the substrate. The electron barrier layer includes p-type Al _r Ga _1-r N layers and p-type Al _s Ga _1-s N layers that are alternately stacked. 0<t<1, 0<w<1, 0<y<x<1, 0<v≦1, 0<r<1, 0<s<1, r≠s.

The UV LED is manufactured using MOCVD technology, and the specific process steps are as follows.
(1) Raise the temperature in the MOCVD reaction chamber to 950° C., control the pressure to 400 mbar, simultaneously inject trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber, and deposit a thickness of about 12 mm on the sapphire substrate. A 5 nm AlN buffer layer is formed.
(2) raising the temperature in the reaction chamber to 1250° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber to form an undoped AlN layer; The thickness is approximately 3500 nm.
(3) Lowering the temperature in the reaction chamber to 1140° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (100 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber, and undoped AlN An undoped Al _t Ga _1-t N layer having a thickness of about 1500 nm is formed on the layer. t=0.50.
(4) keeping the temperature and pressure in the reaction chamber unchanged, injecting hydrogen, trimethylgallium (90 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber, doping silane, and increasing the thickness is about 1200 nm, forming a single N-type _{AlwGa1 -wN} layer. w=0.45 and the doping concentration of Si is 1×10 ¹⁹ cm ⁻³ .
(5) maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and adding silane; Dope to form a single Al _x Ga _1-x N barrier layer with a thickness of about 12 nm. x=0.50 and the doping concentration of Si is 1×10 ¹⁸ cm ⁻³ .
(6) keeping the temperature and pressure in the reaction chamber unchanged, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas into the reaction chamber until the thickness is about 2.5 nm; A single layer of Al _y Ga _1-y N well layer is formed. y=0.25.
(7) Steps (5) and (6) are repeated for a total of 8 cycles to form a quantum well structure for 8 cycles.
(8) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and finally A single Al _x Ga _1-x N barrier layer is formed. The thickness is about 12 nm and x=0.50.
(9) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (250 mL/min) and ammonia gas into the reaction chamber to obtain a thickness of A single p-type Al _r Ga _1-r N layer with a thickness of about 7.5 nm is formed. r=0.65 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(10) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _s Ga _1- sN layer with a thickness of about 5 nm. s=0.45 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(11) Steps (9) and (10) are repeated for a total of 5 cycles to form an electron barrier layer for 5 cycles.
(12) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (60 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _v Ga _1-v N layer with a thickness of about 6 nm.
(13) Lowering the temperature in the reaction chamber to 1000° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (100 mL/min) and ammonia gas into the reaction chamber to dope dicyclopentadienylmagnesium Cp ₂ Mg. to form a single GaN layer with a thickness of about 2 nm. The doping concentration of Mg is 3×10 ¹⁹ cm ⁻³ .
(14) stop injecting source materials such as hydrogen, methyl gallium, and ammonia into the reaction chamber, reduce the temperature in the reaction chamber to 900°C, maintain the pressure at 200 mbar, and inject nitrogen gas into the reaction chamber; High temperature annealing is performed. Annealing time is 1 min.
(15) Lower the temperature in the reaction chamber to 750° C., maintain the pressure at 200 mbar, and then inject nitrogen gas into the reaction chamber to perform low temperature annealing. Annealing time is 5 min.
(16) Repeat steps (12) to (15) for a total of 5 cycles to form a hole injection layer on the electron blocking layer to obtain an ultraviolet LED epitaxial wafer. The hole injection layer includes five sublayers, and each sublayer includes a p-type Al _v Ga _1-v N layer and a p-type GaN layer that are sequentially stacked upward from the substrate.

When the UV LED epitaxial wafer is processed into a UV LED chip with a size of 1 mm x 1 mm, and a current of 350 mA is applied, the emission wavelength of the UV LED chip is 310 nm, the brightness is 120 mW, and the positive voltage is 6.0 V. be. The UV LED has a high efficiency phototherapy effect.

<Example 5>
This embodiment provides an ultraviolet LED, the schematic diagram of which is shown in FIG. Including Al _t Ga _1-t N layer, N-type Al _w Ga _1-w N layer, Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer, electron barrier layer and hole injection layer . The hole injection layer includes at least one sub-layer, each sub-layer being a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga _1-v N layer, and upwardly from the substrate. layer and a P-type GaN layer. the electron barrier layer includes p-type Al _r Ga _1-r N layers and p-type Al _s Ga _1-s N layers alternately stacked;
0<t<1, 0<w<1, 0<y<x<1, 0<v<1, 0<u<1, 0<r<1, 0<s<1, u≠v, r≠ is s.

The UV LED is manufactured using MOCVD technology, and the specific process steps are as follows.
(1) Raise the temperature in the MOCVD reaction chamber to 850° C., control the pressure to 400 mbar, simultaneously inject trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber for 1.5 min, and deposit a thickness of about 1.5 min on the sapphire substrate. An AlN buffer layer of 12.5 nm is formed.
(2) raising the temperature in the reaction chamber to 1250° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber to form an undoped AlN layer; The thickness is approximately 4000 nm.
(3) Lowering the temperature in the reaction chamber to 1140° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylgallium (100 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber. A layer of undoped Al _t Ga _1-tN with a thickness of about 1500 nm is formed on the undoped AlN layer. t=0.50.
(4) keeping the temperature and pressure in the reaction chamber unchanged, injecting hydrogen, trimethylgallium (90 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber, doping silane, and increasing the thickness A single N-type Al _w Ga _1-w N layer with a thickness of about 1000 nm is formed. w=0.45 and the doping concentration of Si is 1×10 ¹⁹ cm ⁻³ .
(5) Maintaining the temperature in the reaction chamber at 1100° C., adjusting the pressure to 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and adding silane. Dope to form an Al _x Ga _1-x N barrier layer with a thickness of about 12 nm. x=0.50 and the doping concentration of Si is 1×10 ¹⁸ cm ⁻³ .
(6) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas into the reaction chamber to obtain a thickness of is about 2.5 nm to form an Al _y Ga _1-y N well layer. y=0.25.
(7) Steps (5) and (6) are repeated for a total of 8 cycles to form a quantum well structure for 8 cycles.
(8) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and finally of Al _x Ga _1-x N barrier layers are formed. The thickness is 12 nm and x=0.50.
(9) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (250 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _r Ga _1-r N layer with a thickness of about 7.5 nm. r=0.55 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(10) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _s Ga _1- sN layer with a thickness of about 6 nm. s=0.50 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(11) Steps (9) and (10) are repeated for a total of 10 cycles to form an electron barrier layer for 10 cycles.
(12) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (80 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _u Ga _1-u N layer with a thickness of 5 nm. u=0.45% and the Mg doping concentration is 2×10 ¹⁹ cm ⁻³ .
(13) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (60 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _v Ga _1-v N layer with a thickness of about 6 nm. v=0.45% and the Mg doping concentration is 2×10 ¹⁹ cm ⁻³ .
(14) Lowering the temperature in the reaction chamber to 1000° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (100 mL/min) and ammonia gas into the reaction chamber to dope with dicyclopentadienylmagnesium Cp ₂ Mg. to form a single GaN layer with a thickness of about 2 nm. The doping concentration of Mg is 3×10 ¹⁹ cm ⁻³ .
(15) stop injecting hydrogen, trimethylgallium, ammonia and other source materials into the reaction chamber, reduce the temperature in the reaction chamber to 900°C, maintain the pressure at 200 mbar, and inject nitrogen gas into the reaction chamber; High temperature annealing is performed. Annealing time is 1 min.
(16) Lower the temperature in the reaction chamber to 750° C., maintain the pressure at 200 mbar, and then inject nitrogen gas into the reaction chamber to perform low temperature annealing. Annealing time is 5 min.
(17) Repeat steps (12) to (16) for a total of 6 cycles to form a hole injection layer on the electron blocking layer to obtain an ultraviolet LED epitaxial wafer. The hole injection layer includes six sublayers, each sublayer including a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga _1-v N layer and a p-type GaN layer, which are stacked. .

The UV LED epitaxial wafer is processed into a UV LED chip with a size of 1 mm ² , and a current of 350 mA is applied, the emission wavelength of the UV LED chip is 310 nm, the brightness is 120 mW, and the positive voltage is 6.0V. The UV LED has a high efficiency phototherapy effect.

<Example 6>
This embodiment provides an ultraviolet LED, _the schematic diagram of which is shown in FIG _{. tN} layer, N-type _{AlwGa1 -wN} layer, _{AlxGa1 -xN} / _{AlyGa1 -yN} multi-quantum well layer, electron barrier layer and hole injection layer. The hole injection layer includes at least one sublayer, each sublayer being a p-type Al _u Ga _1-u N layer and a p-type Al _v Ga _1-v N layer stacked upward from the substrate. layer. The electron barrier layer includes a p-type Al _r Ga _1-r N layer and a p-type Al _s Ga _1-s N layer that are alternately stacked, wherein 0<t<1, 0<w<1, 0<y<x<1, 0<v≤1, 0<u≤1, 0<r<1, 0<s<1, u≠v, r≠s.

The UV LED is manufactured using MOCVD technology, and the specific process steps are as follows.
(1) Raise the temperature in the MOCVD reaction chamber to 850° C., control the pressure to 400 mbar, simultaneously inject trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber, and deposit a thickness of about 25 nm on the sapphire substrate. A certain AlN buffer layer is formed.
(2) Raise the temperature in the reaction chamber to 1250° C., control the pressure to 200 mbar, and inject hydrogen, trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber to form an undoped AlN layer. The thickness is 5000 nm.
(3) The temperature in the reaction chamber is lowered to 1140°C, the pressure is maintained at 200mbar, hydrogen, trimethylgallium (100mL/min), trimethylaluminum (360mL/min) and ammonia gas are injected into the reaction chamber, and the thickness is Form an undoped Al _t Ga _1-tN layer that is about 1000 nm. t=0.50.
(4) keeping the temperature and pressure in the reaction chamber unchanged, injecting hydrogen, trimethylgallium (90 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber, doping silane, and increasing the thickness is about 1200 nm, forming a single N-type _{AlwGa1 -wN} layer. w=0.45 and the doping concentration of Si is 1×10 ¹⁹ cm ⁻³ .
(5) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber to obtain a thickness of A single Al _x Ga _1-x N barrier layer with a thickness of about 12 nm is formed. x=0.50 and the doping concentration of Si is 1×10 ¹⁸ cm ⁻³ .
(6) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas into the reaction chamber to obtain a thickness of A single Al _y Ga _1-y N well layer with a thickness of about 2.5 nm is formed. y=0.25.
(7) Steps (5) and (6) are repeated for a total of 8 cycles to form a quantum well structure for 8 cycles.
(8) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and finally A single Al _x Ga _1-x N barrier layer is formed. The thickness is about 12 nm and x=0.50.
(9) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (250 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _r Ga _1-r N layer with a thickness of about 7.5 nm. r=0.55 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(10) Maintaining the temperature in the reaction chamber at 1100° C., adjusting the pressure to 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _s Ga _1- sN layer with a thickness of about 6 nm. s=0.45 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(11) Steps (9) and (10) are repeated for a total of 4 cycles to form an electron barrier layer for 4 cycles.
(12) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (80 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _u Ga _1-u N layer with a thickness of about 6 nm. u=0.45% and the Mg doping concentration is 2×10 ¹⁹ cm ⁻³ .
(13) Maintaining the temperature in the reaction chamber at 1100° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (60 mL/min) and ammonia gas into the reaction chamber, Pentadienylmagnesium Cp ₂ Mg is doped to form a single p-type Al _v Ga _1-v N layer with a thickness of about 6 nm. v=0.32% and the Mg doping concentration is 2×10 ¹⁹ cm ⁻³ .
(14) stop injecting hydrogen, trimethylgallium, ammonia and other source materials into the reaction chamber, reduce the temperature in the reaction chamber to 850°C, adjust the pressure to 200 mbar, and inject nitrogen gas into the reaction chamber; High temperature annealing is performed. Annealing time is 1 min.
(15) Lower the temperature in the reaction chamber to 650° C., adjust the pressure to 200 mbar, and then introduce nitrogen gas into the reaction chamber to perform low temperature annealing. Annealing time is 4 min.
(16) Repeat steps (12) to (15) for a total of 6 cycles to form a hole injection layer on the electron blocking layer to obtain an ultraviolet LED epitaxial wafer. The hole injection layer includes six sub-layers, each sub-layer including a p-type Al _u Ga _1-u N layer and a p-type Al _v Ga _1-v N layer that are stacked.

The UV LED epitaxial wafer is processed into a UV LED chip with a size of 1 mm ² , and a current of 350 mA is applied, the emission wavelength of the UV LED chip is 310 nm, the brightness is 110 mW, and the positive voltage is 6.0V. The UV LED has a high efficiency phototherapy effect.

<Example 7>
This embodiment provides an ultraviolet LED, _the schematic diagram of which is shown in FIG _{. tN} layer, N-type _{AlwGa1 -wN} layer, _{AlxGa1 -xN} / _{AlyGa1 -yN} multi-quantum well layer, electron barrier layer and hole injection layer. The hole injection layer includes at least one sublayer, each sublayer being a p-type Al _u Ga _1-u N layer and a p-type Al _v Ga _1-v N layer stacked upward from the substrate. layer. The electron barrier layer includes a p-type Al _r Ga _1-r N layer and a p-type Al _s Ga _1-s N layer that are alternately stacked, wherein 0<t<1, 0<w<1, 0<y<x<1, 0<v≤1, 0<u≤1, 0<r<1, 0<s<1, u≠v, r≠s.

The UV LED is manufactured using MOCVD technology, and the specific process steps are as follows.
(1) Raise the temperature of the MOCVD reaction chamber to 850° C., control the pressure to 400 mbar, simultaneously inject trimethylaluminum (150 mL/min) and ammonia gas into the reaction chamber, and deposit a thickness of about 42 nm on the sapphire substrate. A certain AlN buffer layer is formed.
(2) The temperature in the reaction chamber is lowered to 1150°C, the pressure is maintained at 200mbar, hydrogen, trimethylgallium (100mL/min), trimethylaluminum (360mL/min) and ammonia gas are injected into the reaction chamber, and the thickness is A one-layer undoped Al _t Ga _1-tN layer of about 3000 nm is formed. t=0.52.
(3) keeping the temperature and pressure in the reaction chamber unchanged, injecting hydrogen, trimethylgallium (100 mL/min), trimethylaluminum (360 mL/min) and ammonia gas into the reaction chamber, doping silane, and increasing the thickness is about 1500 nm, forming a single N-type Al _w Ga _1-w N layer. w=0.52 and the doping concentration of Si is 1×10 ¹⁹ cm ⁻³ .
(4) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber to obtain a thickness of A single Al _x Ga _1-x N barrier layer with a thickness of about 12 nm is formed. x=0.58 and the doping concentration of Si is 1×10 ¹⁸ cm ⁻³ .
(5) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (50 mL/min) and ammonia gas into the reaction chamber to obtain a thickness of A single Al _y Ga _1-y N well layer with a thickness of about 3.0 nm is formed. y=0.35.
(6) Steps (4) and (5) are repeated for a total of 12 cycles to form a quantum well structure for 12 cycles.
(7) Maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (200 mL/min) and ammonia gas into the reaction chamber, and finally A single Al _x Ga _1-x N barrier layer is formed. x=0.58 and the thickness is about 12 nm.
(8) maintaining the temperature in the reaction chamber at 1150° C., maintaining the pressure at 200 mbar, and injecting hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (250 mL/min) and ammonia gas into the reaction chamber for about 2 min; A single p-type Al _z Ga _1-z N layer doped with dicyclopentadienylmagnesium Cp ₂ Mg and having a thickness of about 30 nm is formed as an electron barrier layer. z=0.65 and the doping concentration of Mg is 1×10 ¹⁹ cm ⁻³ .
(9) The temperature in the reaction chamber is lowered to 1110° C., the pressure is maintained at 200 mbar, hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (80 mL/min) and ammonia gas are injected into the reaction chamber, and dicyclopenta Doping dienylmagnesium Cp ₂ Mg to form a single p-type Al _u Ga _1-u N layer with a thickness of about 5 nm. u=0.45 and the Mg doping concentration is 2×10 ¹⁹ cm ⁻³ .
(10) stop injecting source materials such as hydrogen, methyl gallium, and ammonia into the reaction chamber, reduce the temperature in the reaction chamber to 850°C, maintain the pressure at 200 mbar, and inject nitrogen gas into the reaction chamber; High temperature annealing is performed. The annealing time is 30s.
(11) The temperature in the reaction chamber is lowered to 650° C., the pressure is maintained at 200 mbar, and then nitrogen gas is injected to perform low temperature annealing. Annealing time is 3 min.
(12) Raise the temperature in the reaction chamber to 1100° C., maintain the pressure at 200 mbar, inject hydrogen, trimethylgallium (50 mL/min), trimethylaluminum (60 mL/min) and ammonia gas into the reaction chamber, dicyclopenta Doping dienylmagnesium Cp ₂ Mg to form a single p-type Al _v Ga _1-v N layer with a thickness of about 6 nm. v=0.32 and the Mg doping concentration is 2×10 ¹⁹ cm ⁻³ .
(13) stop injecting source materials such as hydrogen, methyl gallium, and ammonia into the reaction chamber, reduce the temperature in the reaction chamber to 850°C, maintain the pressure at 200 mbar, and inject nitrogen gas into the reaction chamber; High temperature annealing is performed. The annealing time is 30s.
(14) Lowering the temperature in the reaction chamber to 650° C., maintaining the pressure at 200 mbar, continuously injecting nitrogen gas and performing low temperature annealing. Annealing time is 3 min.
(15) Raise the temperature in the reaction chamber to 1000° C., maintain the pressure at 200 mbar, inject hydrogen, trimethylgallium (100 mL/min) and ammonia gas into the reaction chamber to dope with dicyclopentadienylmagnesium Cp ₂ Mg. to form a single GaN layer with a thickness of about 2 nm. The doping concentration of Mg is 3×10 ¹⁹ cm ⁻³ .
(16) stop injecting source materials such as hydrogen, methyl gallium, and ammonia into the reaction chamber, reduce the temperature in the reaction chamber to 850°C, maintain the pressure at 200 mbar, and inject nitrogen gas into the reaction chamber; High temperature annealing is performed. The annealing time is 30s.
(17) Lowering the temperature in the reaction chamber to 650° C., maintaining the pressure at 200 mbar, continuously injecting nitrogen gas and performing low temperature annealing. Annealing time is 3 min.
(18) Repeat steps (9) to (17) for a total of 4 cycles to form a hole injection layer on the electron blocking layer to obtain an ultraviolet LED epitaxial wafer. The hole injection layer includes four sublayers, each sublayer being a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga _1-v N layer and a p-type GaN layer, which are sequentially stacked. including.

The UV LED epitaxial wafer is processed into a UV LED chip with a size of 1 mm ² , and a current of 350 mA is applied, the emission wavelength of the UV LED chip is 280 nm, the brightness is 120 mW, and the positive voltage is 6.0V. The UV LED has a highly effective bactericidal action.

Finally, it should be noted that the above embodiments are for describing the technical solutions of the present invention, but not for limiting it. Those skilled in the art can modify the technical solutions described in each of the above embodiments, or make equivalent replacements for some or all of the technical features thereof, and these modifications or replacements should understand that the essence of the corresponding technical solution does not depart from the scope of the technical solution of each embodiment of the present invention.

Claims (5)

A substrate and an undoped Al _t Ga _1-t N layer, an N-type Al _w Ga _1-w N layer, and an Al _x Ga _1-x N/Al _y Ga ₁ sequentially stacked upward from the substrate. _-y N multi-quantum well layer, an electron barrier layer and a hole injection layer,
said hole injection layer comprising at least two periodically repeated sub-layers;
Each sub-layer includes a p-type Al _u Ga _1-u N layer, a p-type Al _v Ga _1-v N layer, and a p-type GaN layer, which are sequentially stacked in an upward direction from the substrate. 0.1 ≤ v ≤ 1, 0.1 ≤ u ≤ 1, u ≠ v,
0<t<1, 0<w<1, 0<y<x<1,
The Al _x Ga _1-x N/A _y Ga _1-y N multi-quantum well layer includes Al _x Ga _1-x N barrier layers and Al _y Ga _1-y N well layers alternately stacked. The number of times of alternate lamination is 2 to 50, and the lower layer closest to the substrate and the farthest from the substrate in the Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer Both upper layers are Al _x Ga _1-x N barrier layers,
the Al _x Ga _1-x N barrier layer has a thickness of 5 to 25 nm;
the Al _y Ga _1-y N well layer has a thickness of 1 to 5 nm;
Al content of the Al _y Ga _1-y N well layer is lower than Al content of the electron barrier layer,
The electron barrier layer has a superlattice structure in which a P -type Al _r Ga _1-r N layer and a P-type Al _s Ga _1-s N layer are alternately stacked, and the electron barrier layer is a P-type Al _r Ga _{1 −r} N layer, ends with P-type Al _s Ga _1-s N layer , 0<r<1, 0<s<1, r≠s, and the number of times of alternate stacking is 2 to 100 is
An ultraviolet LED characterized by: The hole injection layer has a total thickness of 10 to 500 nm,
and/or the doping concentration of the hole injection layer is between 1×10 ¹⁷ and 5×10 ²⁰ cm ⁻³ . The ultraviolet LED of claim 1, wherein the Al content of the Al _y Ga 1 _- yN well layers is lower than the Al content of the undoped Al _t Ga _1-tN layers. A method for manufacturing an ultraviolet LED,
undoped Al _t Ga _1-t N layer, N-type Al _w Ga _1-w N layer, Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer, electron barrier layer and sequentially forming hole injection layers;
said hole injection layer comprising at least two periodically repeated sub-layers;
0<t<1, 0<w<1, 0<y<x<1,
The Al _x Ga _1-x N/A _y Ga _1-y N multi-quantum well layer includes Al _x Ga _1-x N barrier layers and Al _y Ga _1-y N well layers alternately stacked. The number of times of alternate lamination is 2 to 50, and the lower layer closest to the substrate and the farthest from the substrate in the Al _x Ga _1-x N/Al _y Ga _1-y N multi-quantum well layer Both upper layers are Al _x Ga _1-x N barrier layers,
the Al _x Ga _1-x N barrier layer has a thickness of 5 to 25 nm;
the Al _y Ga _1-y N well layer has a thickness of 1 to 5 nm;
Al content of the Al _y Ga _1-y N well layer is lower than Al content of the electron barrier layer,
forming the hole injection layer includes forming at least two of the sublayers, wherein forming each of the sublayers comprises:
A p-type Al _u Ga _1-u N layer, a p-type Al _v Ga _1-v N layer and a p-type GaN layer are sequentially formed, and 0.1≦v≦1, 0.1≦u≦1, u≠ v, comprising the step of
The electron barrier layer has a superlattice structure in which a P -type Al _r Ga _1-r N layer and a P-type Al _s Ga _1-s N layer are alternately stacked, and the electron barrier layer is a P-type Al _r Ga _{1 −r} N layer, ends with P-type Al _s Ga _1-s N layer , 0<r<1, 0<s<1, r≠s, and the number of times of alternate stacking is 2 to 100 is
A method for manufacturing an ultraviolet LED, characterized by: The process of forming the hole injection layer further includes performing an annealing;
The annealing comprises sequential high temperature annealing and low temperature annealing,
The temperature of the high temperature annealing is 850-950° C., the time is 10 s-20 min,
5. The manufacturing method according to claim 4 , wherein the low temperature annealing temperature is 650-750° C. and the time is 1-60 min.

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