WO2017127958A1 - Optical pumping light-emitting device and preparation method for monolithic integrated optical pumping light-emitting device - Google Patents

Abstract

Disclosed is an optical pumping light-emitting device, comprising: a transparent substrate for the growth of nitride, a yellow-green-red quantum well structure and a covering layer located above the yellow-green-red quantum well structure, wherein a plurality of unit bodies including but not limited to nitride are arranged at a side of the substrate, the unit bodies have a slanted side face, and the yellow-green-red quantum well structure is located on the top of the unit bodies. Further provided is a preparation method for a monolithic integrated optical pumping light-emitting device. Compared with the prior art, the optical pumping light-emitting device in the present invention can reduce pressure stress, and improve light-emitting efficiency.

Description

Optical pumping light emitting device and method for preparing monolithically integrated optical pumping light emitting device Technical field

The present invention relates to an optical pumping light emitting device and a method of fabricating a monolithically integrated optical pumping light emitting device.

Background technique

Energy-efficient InGaN/GaN quantum well light-emitting diodes (LEDs) are gradually replacing traditional, high-energy, low-luminance luminous bulbs. However, such diodes have low luminous efficiency and unstable color in the yellow, green and red wavelength bands due to the compressive stress inside the luminescent medium InGaN in the quantum well. This compressive stress is mainly derived from lattice mismatch, that is, InGaN having a large lattice parameter is grown on a GaN crystal face having a small lattice parameter. A longitudinal electric field is formed by the piezoelectric effect. This electric field always separates the electrons of the InGaN quantum well from the holes, so they cannot be effectively combined to emit light. This compressive stress has other side effects: it not only includes reducing the amount of In in the InGaN quantum well medium during growth, but a more prominent problem is the V-shaped defect. V-type defects are prone to short circuits, ie LED failure. Despite a lot of efforts, including the use of crystal orientation without piezoelectric effect, it has not been able to develop stable, high-efficiency yellow-green LEDs, not to mention red LEDs.

In recent years, a new technology is being taken seriously, namely optically pumped LEDs. This technology uses an optical pumping method that has been widely used in the optoelectronics industry. Specifically, optical pumping does not use an electric field to inject electrons and holes into a green or yellow InGaN quantum well to illuminate it. Instead, it emits electrons in a yellow-green quantum well with light emitted by a highly efficient and reliable blue-violet LED. Holes, electrons and holes recombine to produce yellow-green light.

This optical pumping method has three important advantages: first, overall, the efficiency of converting electrical energy into light energy is ensured; secondly, since the electric field is not applied to the quantum well of yellow-green light, the LED failure rate is low; Since the number of electrons and holes excited by blue-violet light in the yellow-green quantum well is much lower than the number of electrons and holes injected by the electric field, the color of the LED is relatively stable; finally, by adjusting the intensity of the blue-violet light and the yellow-green light quantum well The number of LEDs thus forming various colors.

This type of prior art can be divided into two categories:

1) The yellow-green light quantum well and the blue-violet light LED are on the same side of the substrate. In this category, there are two ways: First, the yellow-green light quantum well is placed inside the blue-violet LED PN junction. The problem is that in the process of growing this structure, V-type defects will be formed, the quality is poor, and the LED is easy to fail. Second, the yellow-green light quantum well is placed outside the blue-violet LED PN junction and grows at the top of the LED p-type. On the material, but this will not effectively control the distribution of holes during the luminescence process, and the luminous efficiency of the blue-violet LED will therefore decrease. It is of course proposed that the n-type material is first grown on the p-type material at the top of the LED to form a tunnel diode, and then the yellow-green light quantum well is grown, so that the n-type material can be used to control the uniformity of the holes, but in the growth n-type During the course of the material, the blue-violet quantum well has either deteriorated.

2) Yellow-green quantum wells and blue-violet LEDs are on the sides of the substrate, one example of this type of technology is The OSRAM proposed that the yellow-green quantum well and the blue-violet light grow on two different sapphire, respectively, and then reduce the thickness of the former substrate and stick it to the surface of the latter; another example is the University of California, Santa Barbara. Laho's proposed yellow-green quantum well and blue-violet LED are respectively grown on both sides of a single crystal (11-22) GaN substrate, but it excludes the use of p-type nitride material on one side of the yellow-green quantum well. That is, the internal electric field using the diode is excluded to reduce the electric field formed by the compressive stress and the piezoelectric effect.

The existing optical pumping method has yet to be optimized and improved. First, the prior art uses a plane-to-plane pumping method. The intensity of the blue-violet light reaching the yellow-green-red-light quantum well is not high enough, and it is necessary to increase the free electrons excited by blue-violet light. And the concentration of holes ensures that the yellow-green red quantum well has suitable quantum efficiency and luminous efficiency. Secondly, from the current point of view, the single crystal GaN substrate is still very expensive, and the output is low, which cannot meet the needs of the light-emitting industry, so the novel light-emitting device The design must take into account the use of sapphire substrates; however, since the thermal expansion coefficient of sapphire is much larger (about 35%) than that of nitrides, that is, the thermal expansion mismatch, during the growth and cooling process, a very large Large compressive stress (300-500 MPa), so the compressive stress must be effectively reduced; in addition, in order to fully absorb blue-violet light into yellow-green or red light, the number of quantum wells is large, so the consumption of indium organic metal source will Become a problem. In addition, the design of the yellow-green-red quantum wells must also reduce the internal compressive stress caused by lattice mismatch and thermal expansion mismatch, and reduce the electric field caused by compressive stress in the quantum well.

Summary of the invention

The first technical problem to be solved by the present invention is to provide an optical pumping light-emitting device that reduces compressive stress and improves luminous efficiency in view of the problems of the prior art described above.

A second technical problem to be solved by the present invention is to provide a method of fabricating the above monolithically integrated optical pumping light-emitting device.

The first technical solution adopted by the present invention to solve the above technical problem is: an optical pumping light emitting device comprising a transparent substrate for nitride growth, a yellow-green-red quantum well structure, and a yellow-green-red quantum well structure The cover layer is characterized in that: a plurality of unit bodies including but not limited to nitrides are disposed on one side of the substrate, the unit body has inclined sides, and the yellow-green-red quantum well structure is located at the top of the unit body.

According to an aspect of the invention, the unit body is a cone having a cone top cross-sectional diameter of 0.5 μm to 50 μm, and a base side of the inclined side of the unit body is 89° to 20°, the unit The height of the body is 500 nm to 50 μm.

According to another aspect of the present invention, the unit body is a strip body having a trapezoidal cross section, the upper side of the trapezoidal section is 0.5 μm to 50 μm, and the bottom side of the inclined side surface of the unit body is 89° to 20 °, the height of the unit body is 500 nm to 50 μm.

Further, the unit body has a nitrogen polarity, and the upper portion of the unit body has a Mg-doped p-type nitride, and the doping concentration of Mg is 2 ^× 10 ⁺¹⁷ cm ^-3 to 8×10 ⁺¹⁹ cm ^-3 . The thickness of the Mg-doped p-type nitride is not less than 10 nm, so that an in-diode electric field can be formed with the n-type material above it, and the electric field formed by the piezoelectric effect and the compressive stress is opposite to each other, thereby increasing the yellow-green red quantum well. Luminous efficiency.

Further, the unit body is a gallium polarity, and an upper portion of the unit body has an n-type doped nitride with a doping concentration of 2 ^× 10 ⁺¹⁷ cm ⁻³ to 8×10 ⁺¹⁹ cm ⁻³ , and the doping The thickness of the n-type nitride is not less than 10 nm, and an in-diode electric field can be formed with the p-type doped nitride above it, and the electric field formed by the piezoelectric effect and the compressive stress is opposite to each other, thereby increasing the yellow-green red quantum well. Luminous efficiency.

Further, the adjacent unit cells are not connected to each other, the substrate is sapphire, and the surface of the substrate is exposed between the unit bodies, since the nitride grown on the sapphire always has The compressive stress, the substrate is always convexly warped, and the sapphire substrate can be easily bent after the unit bodies are not connected to each other.

Further, a gap between the side surface of the unit body and the adjacent unit body is coated with a light reflecting layer to increase the surface light reflectance, and the color of the light emitting device can be changed by adjusting the coverage of the light reflecting layer.

Preferably, the light reflecting layer is a metal or a dielectric coating.

Further, the unit body includes a distributed Bragg reflection structure composed of nitride, thereby increasing the output efficiency of yellow-green-red.

Preferably, the quantum well component of the yellow-green-red quantum well structure is In _y Ga _1-y N, wherein 0.18 _{≤ y ≤} 0.7; and the barrier of the yellow-green red quantum well is In _a Al _b Ga _1-ab N, wherein 0≤a≤y-0.01, 0≤b≤0.3, the barrier of the yellow-green-red quantum well includes an n-type or p-type doped layer, and the doping concentration is at least 1 ^× 10 ⁺¹⁶ cm ^-3 .

Further, the bottom of the yellow-green-red quantum well structure includes at least one nitride buffer layer having a thickness of not less than 5 nm, and the composition of the nitride buffer layer is In _x Al _y Ga _1-xy N, where 0≤x≤ 0.3, 0 ≤ b ≤ 0.3.

Preferably, the cover layer is the uppermost quantum well barrier.

Further, the cover layer comprises a blue-violet film reflective structure comprising a distributed Bragg reflection structure or a metal/dielectric optical filter to increase the actual use intensity of the blue-violet light; or the cover layer a yellow-green-red film reflective structure comprising a distributed Bragg reflection structure or a metal/dielectric optical filter to adjust the structure of the line and the direction of illumination by forming a vertical cavity surface emitting laser (VCSEL) Sex.

The second technical solution adopted by the present invention to solve the above technical problem is: a method for preparing a monolithically integrated optical pumping light emitting device, comprising: the following steps:

1) providing a substrate: providing a single-sided polished substrate;

2) providing a nitride for forming a unit body: providing a nitride for forming a unit body on a polished side of the substrate, and forming a protective layer of nitride to form a substrate;

3) forming a unit body: forming an etching mask on the substrate obtained in step 2), and forming a unit body having inclined sides by plasma etching;

4) cleaning the etching mask: cleaning the etching mask formed in step 3) and forming a protective layer capable of functioning as a nitride growth mask;

5) polishing the other side of the substrate: polishing the other side of the substrate;

6) forming a blue-violet LED nitride structure: growing blue-violet LED nitrogen on the polished other side of the substrate Structure and protective layer;

7) exposing the top of the unit body: exposing the top of the unit body using photolithography and plasma etching techniques;

8) growing a yellow-green-red quantum well structure and a cap layer: growing a yellow-green-red quantum well structure and a cap layer on top of the unit body;

9) depositing a light reflecting layer on the side and the gap of the inclined body of the unit body;

10) forming a blue-violet LED electrode and a reflective structure: forming a blue-violet LED electrode and a reflective structure on a side of the blue-violet LED nitride structure away from the substrate (1);

11) device package: the substrate obtained after step 10) is cut into small pieces as a single light emitting device and packaged;

The steps 3), 4) can be carried out after step 6).

Further, in step 3), a metal etching mask is first formed on the substrate formed in the step 2) by a photolithography process, an electron beam evaporation, and a lift-off process; then, a photolithography process and a negative photoresist are used. Another layer of negative photoresist of the same shape is formed on the metal etch mask as an etch mask; and a plasma etching apparatus is used to form a unit body having inclined sides.

Compared with the prior art, the invention has the advantage that a new optical pumping method, ie, point-to-point pumping, is used, thereby:

1) The sides of the unit body are inclined, and they can function as a condensing light to adjust the quantum efficiency of the yellow-green-red quantum well;

2) The side of the unit body is inclined, and the top section of the unit is smaller in size, which will reduce the compressive stress of the yellow-green-red quantum well, thereby increasing the luminous efficiency of the yellow-green-red quantum well;

3) The side of the unit body is inclined, and the top section of the unit is smaller in size, which will reduce the loss of the Inorganic metal source, thereby reducing the production cost;

4) When the substrate is sapphire, since the bottoms of the respective unit bodies are not connected to each other, the substrate can be bent without restriction, thereby reducing the compressive stress of the blue-violet LED on the other side, and ensuring luminous efficiency;

5) The color of the optically pumped LED can be changed by changing the distance between the bottoms of the cone and the presence or absence of metal and dielectric coating.

DRAWINGS

1 is a schematic cross-sectional view of an embodiment of an optical pumping light emitting device of the present invention;

2 is a schematic cross-sectional view showing Embodiments 1 and 2 of the monolithically integrated optical pumping light emitting device of the present invention, showing the overall positional relationship of the components;

3 is a schematic cross-sectional view showing a first embodiment of the monolithically integrated optical pumping light emitting device of the present invention;

4 is a schematic view showing the electrode structure of the monolithically integrated optical pumping light emitting device of FIG. 3;

Figure 5 is a schematic cross-sectional view showing a second embodiment of the monolithically integrated optical pumping light-emitting device of the present invention;

6 is a schematic view of a strip-shaped unit body projection of the monolithically integrated optical pumping light emitting device of FIG. 5.

detailed description

The invention will be further described in detail below with reference to the embodiments of the drawings.

Referring to Figure 1, a preferred embodiment of an optically pumped light emitting device of the present invention is shown. The optical pumping light-emitting device comprises a transparent nitride growth substrate 1, a plurality of unit cells 3 of an island type or a belt type having inclined sides on one side of the substrate 1, and a yellow-green-red quantum well structure 4 at the top of the unit body 3. The cover layer 5 is located above the yellow-green-red quantum well structure 4.

The substrate 1 may be selected from any of the following materials, but is not limited to these materials: (0001) plane sapphire (undoped-alumina single crystal), (0001) plane gallium nitride (GaN) single crystal and ( 0001) Surface aluminum nitride single crystal. The substrate 1 may be intentionally chamfered so as to deviate from the [0001] direction by 0 to 6°, and the deviation direction may be toward the (1-100) plane or the (11-20) plane of the substrate 1, or on the substrate 1 (1) -100) between the face and the (11-20) face. Non-polar or semi-polar nitrides can also be selected as well as sapphire substrates that can be used to grow non-polar or semi-polar nitrides. Preferably, the substrate 1 has a thickness of 0.4 to 5 mm, and the transparency is in the 385 nm to 500 nm spectral range, and the transmittance is not less than 60%.

The unit body 3 includes, but is not limited to, nitride In _a Al _b Ga _1-ab N (0 ≤ a ≤ 0.3, 0 ≤ _b ≤ 1), and may also include a substrate. A distributed Bragg reflection structure (DBR) composed of nitride may also be included as a reflective structure of the yellow-green-red band, thereby increasing the output efficiency of yellow-green-red. The base angle α of the side slope is preferably 89° to 20°, and the height h is preferably 500 nm to 50 μm. The unit body 3 includes an n-type dopant material, and the doping concentration may be 1 ^× 10 ⁺¹⁷ cm ^-3 to 2x10 ⁺¹⁹ cm ^-3 ; or the unit body 3 includes a p-type dopant material, and the doping concentration may be 5×10 ^{+ 17} cm ^-3 to 8x10 ⁺¹⁹ cm ^-3 . The gap between the side surface of the unit body 3 and the adjacent unit body 3 is coated with a light reflecting layer 32, which may be a metal, a dielectric material, or a composite thereof, and the thickness of the light reflecting layer 32 is preferably 5 nm to 3 μm, and the metal material may be one or more of Ni, Au, Ag, Ti, Al, Ta, W, Cr, Cu, In, Pt, Pd, but is not limited to these materials; The electrocoat layer may be selected from one or more of SiO ₂ , Si _x N, and a flowable oxide. The color of the optically pumped light emitting device can be adjusted by varying the coverage of the metal or dielectric coating.

When the unit body 3 is a nitrogen polar material, the upper portion of the unit body 3 includes a p-type doped nitride film (doping concentration: 2x10 + ¹⁷ cm ^-3 to 8x10 + ¹⁹ cm ^-3 ), and the thickness is not less than 10 nm. Forming a diode internal electric field with the cover layer 5 or the yellow-green red quantum well structure 4 including the n-type doped layer (doping concentration: 5x10 ⁺¹⁶ cm ^-3 to 5x10 ⁺¹⁹ cm ^-3 ); the electric field and the piezoelectric field The electric field formed by the effect and the compressive stress is opposite in direction, which will increase the luminous efficiency of the yellow-green-red quantum well 4.

When the unit body 3 is a gallium polar material, the upper portion of the unit body 3 includes an n-type doped nitride film (doping concentration: 2x10 + ¹⁷ cm ^-3 to 8x10 + ¹⁹ cm ^-3 ), and the thickness is not less than 10 nm. Forming a diode internal electric field with a cap layer 5 or a yellow-green red quantum well structure 4 including a p-type doped layer (doping concentration: 5x10 ⁺¹⁶ cm ^-3 to 5x10 ⁺¹⁹ cm ^-3 ); the electric field and piezoelectric The electric field formed by the effect and the compressive stress is opposite in direction, which will increase the luminous efficiency of the yellow-green-red quantum well 4.

The yellow-green-red quantum well structure 4 is located at the top of the unit body 3, and includes at least a quantum well number of 1 to 100 and a quantum well barrier number of 2 to 101. Since the top size of the unit body 3 is small, the compressive stress caused by the lattice mismatch in the quantum well is alleviated, thereby reducing the possibility of formation of dislocations and V-type defects. The composition of the quantum well is In _y Ga _1-y N (0.18 _{≤ y} ≤ 0.7); the composition of the barrier is In _a Al _b Ga _1-ab N (0 ≤ a ≤ y - 0.01, 0 ≤ _b ≤ 0.3), the barrier of the yellow-green-red quantum well includes an n-type or p-type doped layer with a doping concentration of at least 1 ^× 10 ⁺¹⁶ cm ^-3 . In all the yellow-green-red quantum wells 4 and their barriers, the content of In can be gradually increased, and the content of Ga can be gradually reduced. The variation can be stepped or continuous to reduce the formation possibility of dislocations and V-type defects. . Preferably, the barrier is Si or Ge doped to increase the electron concentration of the background. Yellow-red bottom 4 of the quantum well structure comprises at least a thickness not less than 5nm nitride buffer layer, its composition _{In x Al y Ga 1-xy} N, wherein 0≤x≤0.2,0≤b≤0.3. It can be either n-type doped or p-type doped, but it does not absorb pump light. It can moderate the compressive stress of the yellow-green-red quantum well or provide a better surface for the growth of the yellow-green-red quantum well structure 4.

The cover layer 5 is preferably the uppermost quantum well barrier; preferably, the cover layer 5 may comprise a blue-violet light reflective structure comprising a distributed Bragg reflection (DBR) structure or a metal/dielectric optical filter, Thereby increasing the actual use intensity of blue-violet light, such a reflective structure may be a nitride or other materials such as TaO ₂ /SiO ₂ , Ta ₂ O ₅ /SiO ₂ and the like. Preferably, the cover layer 5 may also include a yellow-green-red light-reflecting structure including a distributed Bragg reflection (DBR) structure or a metal/dielectric optical filter to form a vertical cavity surface emitting laser (VESEL), The structure of the line and the directivity of the light are adjusted. Such a reflective structure may be a nitride or other materials such as TaO ₂ /SiO ₂ , Ta ₂ O ₅ /SiO ₂ or the like.

By using the unit body 3 having the inclined sides, 1) the unit body 3 can use an n-type or p-type material to form an in-diode electric field with the nitride above it, applied to the quantum well in the yellow-green-red quantum well structure 4. Since this electric field can be opposite to the direction of the electric field caused by the pressure in the yellow-green-red quantum well 4, the electric field caused by the compressive stress of the yellow-green-red quantum well is reduced, thereby increasing the luminous efficiency; 2) the light focusing action is performed, thereby improving the photoexcitation luminescence of the yellow-green-red quantum well 4. Efficiency; 3) Since the unit bodies 3 are not connected to each other, the substrate 1 can be freely bent, thereby reducing the compressive stress of the blue-violet LED nitride structure 2, and thus the substrate 1 can use a low-cost sapphire substrate.

However, the above-described optical pumping light-emitting device must use other light sources as a pumping source to emit light. For example, it is directly bonded to the light emitting diode to form a yellow-green-red light-emitting device; or directly pumped by a blue laser tube to generate a yellow-green-red laser. But these methods can lead to large and inefficient devices. A preferred method is to integrate with the pump source during the formation of the optically pumped light emitting device to form a monolithically integrated optical pumping light emitting device.

Thus, as shown in FIG. 2, which is a general structural diagram of a monolithically integrated optical pumping light emitting device of the present invention, the following is a general description of a monolithically integrated optical pumping light emitting device (ie, the following monolithic film) Embodiment 1 of the integrated optical pumping light-emitting device and the second embodiment have the following features: a blue-violet LED nitride structure 2 and a blue-violet LED electrode are disposed on the other side of the substrate 1 on the basis of the above-mentioned optical pumping light-emitting device And the reflective structures 6, 7, 8 and the blue-violet LED electrodes and the reflective structure may further have a carrier or a heat sink 9.

The blue-violet LED nitride structure 2 preferably has an emission wavelength of 375 nm to 500 nm. In this band, generally speaking, the shorter the emission wavelength of the blue-violet LED nitride structure 2, the higher the efficiency of the blue-violet tube to convert electrical energy into light energy. In the process of growing the yellow-green-red quantum well structure 4, the blue-violet quantum well will more stable. The surface of the blue-violet LED nitride structure 2 is subjected to an increase in conductance, including ITO (Indium Tin Oxide) deposition and formation of a Ni _x O ultra-thin layer (usually 0.5 to 10 nm), thereby adjusting the blue-violet LED nitride structure 2 luminescence Uniformity.

The blue-violet LED electrode and the reflective structure comprise a patterned insulating layer 6, an n-type conductive electrode 7, a p-type conductive electrode and a light-reflecting layer 8, and the insulating layer 6 has an n-type conductive electrode 7 and a p-type conductive electrode and is reflective The layers 8 are spaced apart and are located entirely on the side of the blue-violet LED nitride structure 2 remote from the substrate 1. The p-type conductive electrode and the light reflecting layer 8 described above may be selected from the following materials, but are not limited to these materials: Ni, Au, Ag, Ti, Al, Ta, W, Cr, Cu, In, Pt, Pd, ITO (indium tin oxide); and the thickness of the insulating layer 6 is preferably 20 nm to 3 μm, and the material of the insulating layer 6 may be selected from the following materials: but not limited to these materials: SiO ₂ , Si _x N or cured Flowing oxides.

The method for preparing the above monolithically integrated optical pumping light emitting device comprises the following steps:

1) Providing a substrate 1: providing a clean single-sided polished substrate 1, the material of the substrate 1 including any of these materials: (0001) surface sapphire, (0001) plane gallium nitride single crystal and (0001) plane aluminum nitride single crystal; when the unit body 3 is of nitrogen polarity, the substrate 1 is intentionally chamfered so as to deviate from the [0001] direction by 0 to 6°, and the deviation direction may be toward the substrate 1 (1-100). a face or (11-20) face, or between the (1-100) face and the (11-20) face of the substrate 1; the thickness of the substrate 1 is preferably 0.4 to 5 mm, and the transparency is preferably 385 nm. In the 500 nm spectral interval, the transmittance is not less than 60%; in this step, the double-sided polished substrate 1 cannot be used because the other side of the polishing is easily nitrided or damaged in the following step 2);

2) Providing a nitride for forming the unit body 3: a layer of nitride In _a Al _b Ga _1-ab for forming the unit body 3 is provided on the polished side of the substrate 1 (0 ≤ a ≤ 0.3, 0 ≤ b ≤1), and forming a protective layer thereof, the method of forming a nitride includes the nitride In _a Al _b Ga _1-ab required for growing the unit body 3 on the polishing surface of the substrate 1 by organometallic vapor phase epitaxy (MOVPE or MOVCD). N (0 ≤ a ≤ 0.3, 0 ≤ b ≤ 1) film; when the substrate 1 in the step 1) is a GaN single crystal, this step includes a nitride structure required for growing the unit body 3 on the surface layer of GaN. , for example, an n-type or p-type nitride, or a distributed Bragg structure, thereby forming a substrate; in this process, the yellow-green-red quantum well structure 4 cannot be grown because they may deteriorate in the following process;

3) Forming the unit body 3: forming a desired unit body 3 on the substrate using a photolithography process and plasma etching, the unit body 3 including a nitride; the photolithography process is formed using a negative photoresist and a metal film a composite etching mask for forming the unit body 3, the negative photoresist has a thickness of 300 nm to 25 μm, and the metal film has a thickness of 30 nm to 5 μm; the plasma etching includes forming the nitride unit body 3, or includes forming nitrogen A unit body 3 composed of a compound and a substrate material. In etching, in order to expose the surface of the substrate, the substrate is inevitably etched; in plasma etching, argon-rich plasma etching is intentionally used, thereby increasing the side slope of the unit body 3;

4) Cleaning the etch mask: cleaning the etch mask formed in step 3) and forming a protective layer; this protective layer can serve as a growth mask for growing the yellow-green-red quantum well structure and its nitride cap layer.

5) Polishing the other side of the substrate 1: polishing the other side of the substrate 1 to the standard for use in an open box;

6) Forming a blue-violet LED nitride structure 2: growing a blue-violet LED nitride structure 2 and a protective layer on the other side of the substrate 1 polished in step 5), in steps 2), 4) and in this step, protecting The layer comprises one or more of these materials: SiO ₂ , Si _x N, or a cured flowable oxide having a thickness of from 3 nm to 5 μm;

7) exposing the top of the unit body 3: exposing the top of the unit body 3 using photolithography and plasma etching techniques;

8) growing a yellow-green-red quantum well structure 4 and a cover layer 5: growing a yellow-green-red quantum well structure 4 and a cover layer 5 on the top of the unit body 3, and a method of growing the yellow-green-red quantum well structure 4 includes an organometallic vapor phase epitaxy (MOVPE);

9) depositing a light reflecting layer 32 on the inclined side surface of the unit body 3 and the gap: the light reflecting layer 32 includes forming a layer of material or a plurality of layers of material using vapor phase evaporation, chemical vapor phase or spin coating, the material of which may be from the following materials Selected but not limited to these materials: Ni, Au, Ag, Ti, Al, Ta, W, Cr, Cu, In, Pt, Pd, SiO ₂ , Si _x N; also includes the use of photolithography to control light reflection Coverage of layer 32;

10) forming a blue-violet LED electrode and a reflective structure: forming a blue-violet LED forming electrode and a reflective structure on a side of the blue-violet LED nitride structure 2 away from the substrate 1, comprising implanting an insulating layer 6 to conduct n-type conductive The electrode 7 and the p-type conductive electrode and the light reflecting layer 8 are spaced apart. The formation of the n-type conductive electrode 7 and the p-type conductive electrode and the light reflecting layer 8 may be performed by a vapor deposition method. Before forming the p-type conductive electrode and the light reflecting layer 8, the insulating layer 6 is implanted, and the implantation method includes spin coating, vapor deposition, and vapor phase evaporation. The p-type electrode contact points are then exposed using photolithography and etching. Finally, at least one or more layers of conductive material are vapor-deposited to form a p-type conductive electrode and a light reflecting layer 8. Conductive materials may be selected from these materials but are not limited to these materials: Ni, Au, Ag, Ti, Al, Ta, W, Cr, Cu, In, Pt, Pd, ITO; reflective materials may be selected from these materials but It is not limited to these materials: Ni, Au, Ti, Al, Ta, W, Cr, Cu, In, Pt, Pd, ITO.

11) Device package: The substrate obtained after step 10) is cut into small pieces as a single light-emitting device package, and the method adopted by the package includes at least one of the following ways: using a bracket to form a power connection and thermal contact, using electroplated copper, or dissipating heat Body 9 is adhered to the reflective electrode.

The above steps 3) and 4) can be after step 6).

Embodiment 1 of the monolithically integrated optical pumping light emitting device of the present invention

As shown in FIG. 3 and FIG. 4, a first detailed embodiment of the monolithically integrated optical pumping light emitting device of the present invention is shown, which is further defined based on the above general description of the monolithically integrated optical pumping light emitting device. for:

The substrate 1 was an undoped (0001) sapphire substrate having a thickness of 0.6 mm.

The blue-violet LED nitride structure 2 comprises, in order from top to bottom: I) unintentionally doped GaN 2a, preferably having a thickness of 2 μm. Including a 30 nm GaN low temperature nucleation layer; II) a Si-doped n-type GaN layer 2b, preferably having a thickness of 2.0 μm, a Si doping concentration of 3×10 ⁺¹⁸ cm ⁻³ ; III) blue-violet quantum well 2c, including 7 pairs, the composition of which is In _x Ga _1-x N (0.01 ≤ _x ≤ 0.30), preferably In _0.14 Ga _0.86 N (2 nm) / Si: GaN (7 nm), Si doping concentration is 1 x 10 + ¹⁸ cm ^-3 ; and IV) Mg-doped p-type nitride layer 2d: composition of Mg: Al _0.25 GaN _0.75 (10 nm) / Mg: GaN, preferably 350 nm thick, Mg doping concentration of 3 x 10 + ¹⁹ Cm ^-3 . In the present embodiment, the blue-violet LED nitride structure 2 has an emission wavelength of approximately 410 nm.

In the present embodiment, the unit body 3 is an island-shaped plurality of cones, and the diameter of the cone top section of each unit body 3 (cone body) is preferably 0.5 to 50 μm, more preferably 10 μm; the height h is preferably 500 nm to 50 μm, more preferably 6 μm; the base angle α is preferably 89° to 20°, more preferably 60°; and the distance d between each unit body 3 is preferably 10 nm to 200 μm, more preferably 5 μm. The top of the unit body 3 is doped with Si at a concentration of 3x10 + ¹⁷ cm ^-3 at 200 nm, thereby increasing the background free electron concentration. The side surface of the unit body 3 and its gap have a Ti (5 nm) / Ag (100 nm) light reflecting layer 32. The small diameter of the top section of the unit body 3 can reduce the compressive stress of the top nitride. On the other hand, since the sides of the unit body 3 are inclined, they can function to focus blue-violet light, which will increase the actual light intensity and adjust Luminous efficiency of the quantum well on top of the cone.

At this time, between the adjacent unit bodies 3, the surface of the sapphire substrate 1 is exposed, and the blue-violet LED nitride structure 2 has a compressive stress caused by thermal expansion mismatch, but since the unit bodies 3 are not connected to each other. The substrate 1 can be bent to reduce the compressive stress of the blue-violet LED nitride structure 2 on the other side. The upper portion of the unit body 3 includes nitride In _a Al _b Ga _1-ab N (0 ≤ a ≤ 0.3, 0 ≤ _b ≤ 1), preferably GaN; the bottom portion includes sapphire, and the bottom sapphire has a thickness of 1 nm to 20 μm. Preferred: 200 nm.

The yellow-green-red quantum well structure 4 includes 25 pairs of In _0.28 Ga _0.72 N (5 nm) / Si: GaN (10 nm) quantum wells with a Si doping concentration of 3 x 10 + ¹⁷ cm ^-3 , thereby increasing the background free electron concentration. There are Si:GaN (10 nm) and In _0.1 Ga _0.9 N (30 nm) at the bottom. This layer of In _0.1 Ga _0.9 N helps to reduce the compressive stress in the quantum well.

The cover layer 5 includes Si:GaN (50 nm) with a Si doping concentration of 3x10 + ¹⁸ cm ^-3 to increase the background free electron concentration. There are also 5 pairs of SiO ₂ (65 nm) / TiO ₂ (40 nm) as a distributed Bragg total reflection layer of blue light.

The blue-violet LED electrode and the reflective structure comprise an insulating layer 6, an n-type conductive electrode 7, a p-type conductive electrode and a light reflecting layer 8, wherein the p-type conductive electrode and the light reflecting layer 8 comprise a p-type conductive electrode 81 and a reflective layer Layer 82. Referring to FIG. 4, a planar projection of the n-type conductive electrode 7 and the p-type conductive electrode 81, wherein the area of the land 71 is 0.5 mm x 0.5 mm, the width between the stages 71 is 0.1 mm, and the depth of the interval is 1100 nm. The n-type conductive electrode 7 is located in the space between the stages 71, has a width of 0.05 mm, and is placed on the surface of the n-type Si:GaN etching. The structure of the n-type conductive electrode 7 is: Ti (20 nm) / Al (150 nm) / Ni (30 nm) / Au (100 nm). In addition, an n-type conductive electrode 7 having a width of 1 mm is used for power connection. The contact point 81 of the p-type conductive electrode 81 is located in the stage 71 and is directly placed on the surface of the p-type GaN. Its shape and size can be used to adjust the uniformity of illumination. The p-type conductive electrode 81 has a structure of Ni (2 nm) / Au (200 nm) and a diameter of 0.2 mm. The insulating layer 6 is distributed between the n-type conductive electrode 7 and the p-type conductive electrode 81 to separate the n-type conductive electrode 7 from the p-type conductive electrode 81, and the insulating layer 6 includes plasma chemical vapor deposition (using plasma) PECVD) formed of 100 nm Si _x N and heat-cured flowable oxide (100 nm), and the light reflecting layer 82 is located under the insulating layer 6 and the p-type conductive electrode 81. The light reflecting layer 82 is Ti (5 nm) / Ag (100 nm).

The heat sink 9 may be Mo because it has a similar coefficient of thermal expansion as the nitride.

In this embodiment, the method for preparing the light emitting device includes the following steps:

1) providing a substrate 1: providing a 2", 0.6 mm thick (0001) sapphire substrate 1, the substrate 1 is polished on one side;

2) Providing nitride for forming the unit body 3: using a conventional growth process of MOVPE, growing 6 μm of GaN, including top 200 nm Si; GaN (doping concentration of 3×10 ⁺¹⁷ cm ^-3 ), and directly in the MOVPE system Growing a 10 nm Si ₃ N ₄ polycrystalline layer as a protective layer to form a substrate;

3) forming a unit body 3: first forming a Ti (30 nm) / Ni (150 nm) disc-shaped metal etching mask having a diameter of 12 μm on the substrate formed in the step 2) by a photolithography process, an electron beam evaporation and a stripping process; Then, using a photolithography process and a negative photoresist, another circular photoresist is formed on the disc-shaped metal etch mask as an etch mask (substantially 7 μm thick); since the photoresist is negative The disc-shaped photoresist etch mask will have an undercut of 2-3 μm, and since the etch mask will be lost during the plasma etching process, such undercut will increase the side tilt of the unit body 3; Next, a plasma etching apparatus is used to form a unit body 3 having a tapered shape; in order to increase the inclination, a lower substrate temperature, a large Ar or a small Cl ₂ gas flow rate is generally used;

4) cleaning the etching mask: cleaning the etching mask in step 3), evaporating 200 nm SiO ₂ as a protective film by electron beam;

5) Polishing the other side of the substrate 1 : polishing the other side of the substrate 1 to achieve the standard for use in an open box;

6) Forming a blue-violet LED nitride structure 2: using a conventional growth process of MOVPE, a blue LED nitride structure 2 and a protective layer thereof are grown on the other side of the substrate 1 polished in step 5), and the protective layer is preferably Si ₃ N ₄ ;

7) exposing the top of the unit body 3: using a photolithography process and plasma etching to expose the nitride plane of the cone top of the unit body 3;

8) growing a yellow-green-red quantum well structure 4 and a cover layer 5; growing a yellow-green-red quantum well 4 and a cover layer 5 at the top of the unit body 3, and the growth temperature of the yellow-green-red quantum well 4 is about 720°;

9) depositing a light reflecting layer 32 on the side and gap of the inclined body of the unit body 3: immersing the substrate after the step 8) in a 5% HF solution, removing all the protective layers; and then using a photolithography process, a lift-off process or electron beam evaporation A light reflecting layer 32 is deposited on the side of the unit body 3 and its gap, preferably a Ti (5 nm) / Ag (200 nm) light reflecting layer, and then evaporating 4 pairs of SiO ₂ (65 nm) / TiO ₂ (40 nm) by electron beam. a distributed Bragg structure as a blue light total reflection layer;

10) forming a blue-violet LED electrode and a reflective structure: using a photoresist as a plasma etching mask, plasma etching to form a terrace 71, and then removing the remaining photoresist; forming a photolithography process, a lift-off process, or electron beam evaporation a type-type conductive electrode 7 having a structure of Ti (20 nm) / Al (150 nm) / Ni (30 nm) / Au (100 nm), and covering a relatively wide boundary of the n-type conductive electrode 7 with a high temperature tape; then forming a p-type Conductive electrode and light-reflecting layer 8: firstly, 100nm Si _x N and spin-on, solidified flowable oxide are formed by plasma chemical vapor deposition (PECVD) to form an insulating layer 6; secondly, a sub-photoresist is used as a plasma etching mask. Membrane, plasma etching removes Si _x N and solidified flowable oxide on the p-type electrode contact point 811, and forms a p-type conductive electrode 81Ni (2 nm) / Ag (200 nm) by electron beam evaporation or lift-off process; Forming a Ti (5 nm) / Ag (100 nm) light reflecting layer 82 by electron beam evaporation; finally removing the high temperature tape on the n-type conductive electrode 7;

11) Device package: The substrate obtained in the step 10) is cut into small pieces as a single light-emitting device package, and the package method uses a bracket to directly contact the heat-dissipating body 9 (the material of the heat-dissipating body 9 including diamond, Cu, Al, Mo, etc.) to the Ag film. The surface is either directly attached to the Ag film with a high temperature adhesive.

Embodiment 2 of the monolithic integrated optical pumping light emitting device of the present invention

As shown in FIG. 5 and FIG. 6, a second detailed embodiment of the monolithically integrated optical pumping light emitting device of the present invention is shown, which is further defined based on the above general description of the monolithically integrated optical pumping light emitting device. for:

The substrate 1 was an undoped chamfered (0001) sapphire substrate having a thickness of 0.6 mm, a bevel rotation axis of [1-100], and a bevel angle of 1.2. The beveling helps to reduce hexagonal surface defects during the growth of the nitrogen-polar GaN required to form the unit body.

The blue-violet LED nitride structure 2 comprises the following arrangement from top to bottom: I) unintentionally doped GaN 2a, preferably 2 μm thick, including GaN low temperature nucleation layer (30 nm); II) Si-doped n-type The GaN layer 2b preferably has a thickness of 2.0 μm and a Si doping concentration of 3×10 ⁺¹⁸ cm ⁻³ ; III) a blue-violet quantum well 2c comprising 7 pairs of components In _0.14 Ga _0.86 N(2 nm)/Si:GaN (7 nm), Si doping concentration is 1x10 ⁺¹⁸ cm ^-3 ; and IV) Mg-doped P-type nitride layer 2d: composition is Mg: Al _0.25 GaN _0.75 (10 nm) / Mg: GaN, preferably The thickness is 350 nm and the Mg doping concentration is 3 x 10 + ¹⁹ cm ^-3 . In the present embodiment, the blue-violet LED nitride structure 2 has an emission wavelength of approximately 410 nm.

The blue-violet LED electrode and the reflective structure are the same as those of the first embodiment. The area of the platform 71 is 0.5 mm x 0.5 mm, the width between the platforms 71 is 0.1 mm, the depth of the interval is 1100 nm, and the n-type conductive electrode 7 is located. In the space between the stages 71, the width is 0.05 mm, the n-type conductive electrode 7 having a width of 1 mm is used for power connection, and the contact point 811 of the p-type conductive electrode 81 is located in the stage 71.

Wherein, the insulating layer 6 comprises 100 nm PECVD Si _x N and a heat curable flowable oxide (100 nm), separating the n-type electrode region 7 and the p-type electrode region 8; the structure of the n-type conductive electrode 7 The structure of the p-type conductive electrode 81 is: Ni (2 nm) / Au (200 nm), the diameter is 0.2 mm; the reflective layer 82 is: Ti (20 nm) / Al (150 nm) / Ni (30 nm) / Au (100 nm); It is Ti (5 nm) / Ag (100 nm).

The shape of the unit body 3 is different from that of the first embodiment. In the present embodiment, it is a strip-shaped unit body, and FIG. 6 is a planar projection of the unit body 3. The center of the unit body 3 ring coincides with the center of the substrate 1, and the unit The cross section of the body 3 is trapezoidal, and the upper side of the trapezoidal cross section is preferably 0.5 μm to 50 μm, more preferably 8 μm; the height h is preferably 500 nm to 50 μm, more preferably 4 μm; and the base angle α is preferably 89° to 20°. More preferably, it is 45°; the distance d between the bottoms of the unit bodies 3 is preferably from 10 nm to 200 μm, more preferably 5 μm.

Nitrogen polar body unit 3, the upper portion of the Mg-doped p- type nitride 31 is, preferably Mg doping concentration of ^{2x10 +17 cm -3 ~ 8x10 +19 cm} -3, more preferably 3x10 ⁺¹⁹ cm ^-3, a thickness of not less than 10nm, preferably from 200nm, so that the concentration of free holes up 3-8x10 ⁺¹⁷ cm ^-3. The side surface of the unit body 3 and its gap have a Ti (5 nm) / Ag (100 nm) light reflecting layer 32. When the unit body 3 is of gallium polarity, the upper portion of the unit body 3 has an n-type doped nitride 31 with a doping concentration of 2x10 ⁺¹⁷ cm ^-3 to 8x10 ⁺¹⁹ cm ^-3 , doped n- The thickness of the type nitride is not less than 10 nm, and an in-diode electric field can be formed with the p-type doped nitride above it, and the electric field formed by the piezoelectric effect and the internal force is opposite, thereby increasing the luminous efficiency of the yellow-green red quantum well. The upper portion of the unit body 3 in the first embodiment may also include the above-described p-type or n-type doped nitride.

The yellow-green-red quantum well structure 4 includes 15 pairs of In _0.28 Ga _0.72 N (5 nm)/GaN (10 nm) grown on top of p-GaN and another 10 pairs of In _0.28 Ga _0.72 N (4 nm) / Si: GaN (7 nm), Si The doping concentration is 8x10 ⁺¹⁷ cm ^-3 . There is GaN (10 nm) at the bottom.

The cover layer 5 is a Si:GaN cladding layer having a Si doping concentration of 3×10 ⁺¹⁹ cm ^-3 and a thickness of 30 nm. Thus, the Si:GaN barrier of the Si:GaN and yellow-green-red quantum wells and the Mg:GaN on the unit body 3 form a diode whose internal electric field will cancel the electric field formed by the piezoelectric stress by the piezoelectric effect, thereby increasing the luminous efficiency. .

The method for preparing the light emitting device in this embodiment includes the following steps:

1) providing a substrate 1: obtaining a 2", beveled 1.2 °, 0.6 mm thick (0001) sapphire substrate 1, the substrate 1 is polished on one side, the bevel axis of rotation is [1-100];

2) Providing a nitrogen polar nitride for forming the unit body 3: using a conventional growth process of MOVPE, first performing high temperature nitridation treatment on the substrate 1, and then growing 4 μm of nitrogen-polar GaN; including 200 nm at the top thereof Mg-doped p-GaN; finally, a 20 nm Si ₃ N ₄ polycrystalline layer is directly grown in the MOVPE system as a protective layer to form a substrate;

3) forming the unit body 3: first forming a Ti (30 nm) / Ni (150 nm) annular metal etching mask having a width of 9 μm on the substrate formed in the step 2) by a photolithography process, a lift-off process or electron beam evaporation; Then, using a photolithography process and a negative photoresist, another layer of circular photoresist is formed on the toroidal metal etch mask as an etch mask (substantially 6 to 10 μm thick), since the photoresist is negative The circular, circular photoresist etch mask will have an undercut of 2-5 μm. Since the etching mask will be lost during the plasma etching process, such undercut will increase the side slope of the unit body 3; then, the plasma etching apparatus is used to form the unit body 3; in order to increase the inclination, generally Use a lower substrate temperature, a large Ar gas or a small Cl ₂ gas flow;

4) cleaning the etching mask: cleaning the etching mask in step 3), forming 200 nm Si _x N as a protective film by PECVD;

5) Polishing the other side of the substrate 1 : polishing the other side of the substrate 1 to achieve the standard for use in an open box;

6) forming a blue-violet LED nitride structure 2: using a conventional growth process of MOVPE, growing a gallium-polar blue-violet LED nitride structure 2 and a protective layer thereof, and the protective layer is preferably a Si ₃ N ₄ protective film;

7) exposing the top of the unit body 3: using a photolithography process and plasma etching to expose the nitride on the top of the ring of the unit body 3;

8) Growth of yellow-green-red quantum well structure 4 and cover layer 5: On the top of the ring of the unit body 3, first grow 10 nm GaN, optimize the surface of the unit body, and then grow 15 pairs of In _0.28 Ga _0.72 N (5 nm) / GaN (10 nm) , regrowth 10 pairs of In _0.28 Ga _0.72 N (5nm) / Si: GaN (7nm), Si doping concentration is 8x10 ⁺¹⁷ cm ^-3 , thereby forming a yellow-green red quantum well 4; then regenerating the long yellow green red quantum well 4 30nm Si: GaN cap layer, Si doping concentration is 3x10 ⁺¹⁹ cm ^-3 ;

9) depositing a light reflecting layer 32 on the side and gap of the inclined body of the unit body 3: immersing the substrate after the step 8) in a 5% HF solution, removing all the protective layers; and then using a photolithography process, a lift-off process or electron beam evaporation On the side of the unit body 3 a light reflecting layer 32, preferably a Ti (5 nm) / Ag (200 nm) light reflecting layer 32; and then spin coating and solidifying the flowable oxide as a protective layer;

10) forming a blue-violet LED electrode and a reflective structure: using a photoresist as a plasma etching mask, plasma etching to form a substrate 71 (Fig. 4), and then removing the remaining photoresist; using a photolithography process, a lift-off process, or an electron The beam is evaporated to form an n-type conductive electrode 7, and a relatively high temperature is used to cover the relatively wide boundary of the n-type conductive electrode 7; then a p-type conductive electrode and a light reflecting layer 8 are formed: first, 100 nm Si _x N and spin coating are deposited by PECVD, Curing a flowable oxide (100 nm) as the insulating layer 6, separating the p-type conductive electrode and the light reflecting layer 8 from the n-type conductive electrode 7; secondly, using a negative photoresist as a plasma etching mask, plasma The Si _x N and the cured flowable oxide on the contact point 811 of the p-type conductive electrode 81 are etched away, and the p-type conductive electrode 81 is formed by electron beam evaporation or lift-off process, Ni (2 nm) / Au (200 nm); Photocuring, forming a Ti (5 nm) / Ag (100 nm) reflective layer 82 by electron beam evaporation; finally removing the high temperature tape on the n-type conductive electrode 7;

11) device package: the substrate obtained in step 10) is cut into small pieces as a single light-emitting device package, and the package method uses a bracket to directly contact the heat sink 9 (including diamond, Cu, Al, Mo, etc.) on the surface of the Ag film, or It is directly fixed to the Ag film with a high temperature adhesive.

Claims (14)

1. An optical pumping light emitting device comprising a transparent substrate for nitride growth (1), a yellow-green-red quantum well structure (4), and a cover layer (5) above the yellow-green-red quantum well structure (4), The invention is characterized in that: a plurality of unit bodies (3) including but not limited to nitrides are disposed on one side of the substrate (1), the unit body (3) has inclined sides, and the yellow-green-red quantum well structure (4) Located at the top of the unit body (3).
2. The optical pumping light-emitting device according to claim 1, wherein said unit body (3) is a tapered body, and said unit body (3) has a cone top cross-sectional diameter of 0.5 μm to 50 μm, said unit body The base angle (α) of the inclined side surface of (3) is 89° to 20°, and the height (h) of the unit body (3) is 500 nm to 50 μm.
3. The optical pumping light-emitting device according to claim 1, wherein the unit body (3) is a strip-shaped body, and the unit body (3) has a trapezoidal cross section, and the upper side of the trapezoidal section is 0.5 μm to 50 μm. The base angle (α) of the inclined side surface of the unit body (3) is 89° to 20°, and the height (h) of the unit body (3) is 500 nm to 50 μm.
4. The optical pumping light-emitting device according to any one of claims 1 to 3, wherein the unit body (3) has a nitrogen polarity, and an upper portion of the unit body (3) has a Mg-doped p The -type nitride (31) has a doping concentration of Mg of 2x10 + ¹⁷ cm ^-3 to 8x10 + ¹⁹ cm ^-3 , and the Mg-doped p-type nitride (31) has a thickness of not less than 10 nm.
5. The optical pumping light-emitting device according to any one of claims 1 to 3, wherein the unit body (3) is a gallium polarity, and an upper portion of the unit body (3) has an n-type doping. The nitride (31) has a doping concentration of 2x10 + ¹⁷ cm ^-3 to 8x10 + ¹⁹ cm ^-3 , and the n-type doped nitride (31) has a thickness of not less than 10 nm.
6. The optical pumping light-emitting device according to any one of claims 2 to 5, wherein adjacent unit cells (3) are not connected to each other, and said substrate (1) is sapphire. The surface of the substrate (1) is exposed between the unit bodies (3).
7. The optical pumping light-emitting device according to claim 1, wherein a gap between a side surface of the unit body (3) and an adjacent unit body (3) is coated with a light reflecting layer (32). The light reflecting layer (32) is a metal or dielectric coating.
8. The optical pumping light-emitting device according to claim 1, wherein said unit body (3) comprises a distributed Bragg reflection structure composed of nitride.
9. The optical pumping light-emitting device according to claim 1, wherein said yellow-green-red quantum well structure (4) has a composition of In _y Ga _1-y N, wherein 0.18 _{≤ y ≤} 0.7; said yellow-green red quantum well structure The composition of the barrier of (4) is In _x Al _b Ga _1-ab N, where 0 ≤ a ≤ y - 0.01, _{0 ≤ b} ≤ 0.3, and the barrier of the yellow-green-red quantum well structure (4) includes n a -type or p-type doped layer having a doping concentration of at least 1 x 10 + ¹⁶ cm ^-3 .
10. The optical pumping light-emitting device according to claim 9, wherein the bottom of the yellow-green-red quantum well structure (4) comprises at least one nitride buffer layer having a thickness of not less than 5 nm, and the nitride buffer layer has a composition of In _x Al _y Ga _1-xy N, where 0 ≤ _x ≤ 0.2 and 0 ≤ b ≤ 0.3.
11. The optical pumping light-emitting device according to claim 1, wherein said cover layer (5) is an uppermost quantum well barrier.
12. The optical pumping light-emitting device according to claim 1 or 11, wherein said cover layer (5) comprises a blue-violet light-reflecting structure comprising a distributed Bragg reflection structure or metal/ a dielectric light filter; and/or the cover layer (5) comprises a yellow-green-red light reflective structure comprising a distributed Bragg reflection structure or a metal/dielectric optical filter.
13. A method for preparing a monolithically integrated optical pumping light emitting device, comprising: the following steps:

    1) providing a substrate (1): providing a single-sided polished substrate (1);

    2) providing a nitride for forming the unit body (3): providing a nitride for forming the unit body (3) on a polished side of the substrate (1), and forming a protective layer to form a substrate;

    3) forming a unit body (3): forming an etching mask on the substrate obtained in step 2), and then forming a unit body (3) having inclined sides by plasma etching;

    4) cleaning the etch mask: cleaning the etch mask formed in step 3) and forming a protective layer that can serve as a nitride growth mask;

    5) polishing the other side of the substrate (1): polishing the other side of the substrate (1);

    6) forming a blue-violet LED nitride structure (2): growing a blue-violet LED nitride structure (2) and a protective layer on the other side of the polishing of the substrate (1);

    7) exposing the top of the unit body (3): exposing the top of the unit body (3) using photolithography and plasma etching techniques;

    8) growing a yellow-green-red quantum well (4) and a cover layer (5): growing a yellow-green-red quantum well (4) and a cover layer (5) on top of the unit body (3);

    9) depositing a light reflecting layer (32) on the inclined side and gap of the unit body (3);

    10) forming a blue-violet LED electrode and a reflective structure: forming a blue-violet LED electrode and a reflective structure on a side of the blue-violet LED nitride structure (2) away from the substrate (1);

    11) device package: the substrate obtained after step 10) is cut into small pieces as a single light emitting device and packaged;

    The steps 3), 4) can be carried out after step 6).
14. A method of fabricating a monolithically integrated optical pumping light emitting device according to claim 13, wherein in step 3), first, on the substrate formed in the step 2) by a photolithography process, an electron beam evaporation and a lift-off process. Forming a metal etch mask; then forming another layer of negative photoresist of the same shape as an etch mask on the metal etch mask by using a photolithography process and a negative photoresist; and then using a plasma etching apparatus to form A unit body (3) having inclined sides.

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