WO2022105163A1

WO2022105163A1 - Light-emitting device and preparation method therefor

Info

Publication number: WO2022105163A1
Application number: PCT/CN2021/094942
Authority: WO
Inventors: 杨顺贵; 刘勇兴; 黎力; 周毅
Original assignee: 重庆康佳光电技术研究院有限公司
Priority date: 2020-11-20
Filing date: 2021-05-20
Publication date: 2022-05-27
Also published as: CN113451460B; CN113451460A

Abstract

Provided is a light-emitting device. The light-emitting device comprises a base substrate, and a first semiconductor layer, a light-emitting layer and a second semiconductor layer which are arranged on the base substrate in a stacked manner. The light-emitting layer comprises light-emitting units which are overlapped periodically, the light-emitting unit comprising an indium-containing quantum well layer, a quantum barrier layer and an indium-containing insertion layer, wherein the indium-containing insertion layer is sandwiched between the indium-containing quantum well layer and the quantum barrier layer, and the content of indium in the indium-containing insertion layer is greater than the content of indium in the indium-containing quantum well layer.

Description

Light-emitting device and preparation method thereof

This application claims the priority of the Chinese patent application with the application number 202011311951.2 and the application name "Light-emitting device and its preparation method", which was submitted to the China Patent Office on November 20, 2020, and the content of the above-mentioned prior application is incorporated by reference into this text.

technical field

The present application relates to the field of semiconductor technology, and in particular, to a light-emitting device and a preparation method thereof.

Background technique

Indium gallium nitride multiple quantum wells have achieved great success as high-efficiency active regions in light-emitting diodes (LEDs) and laser diodes (Laser Diodes). And a light-emitting diode is a semiconductor electronic device that converts electrical energy into light energy. When a current passes through the light-emitting diode, the electrons and holes inside the light-emitting diode recombine in its light-emitting layer to emit monochromatic light.

However, due to the existence of a spontaneous polarization (Spontaneous polarization) electric field in the first semiconductor layer grown on the substrate in the light emitting diode, a lattice mismatch will be formed between the light emitting layer and the first semiconductor layer to form a piezoelectric electrode Piezoelectric polarization electric field. The existence of the polarized electric field will make the energy band of the light-emitting layer tilt, the spatial overlap of the electron and hole wave functions will decrease, and the probability of radiation recombination will decrease, thereby reducing the quantum efficiency in the light-emitting diode. , the shift of the peak wavelength when the current changes will cause the display color difference.

technical problem

In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a light-emitting device and a preparation method thereof, aiming at solving the problem of how to improve the light-emitting efficiency of Micro-LEDs.

technical solutions

A light-emitting device, comprising a first semiconductor layer, a light-emitting layer and a second semiconductor layer sequentially stacked on a base substrate; the light-emitting layer includes periodically overlapping light-emitting units, and the light-emitting unit includes an indium-containing quantum well layer , a quantum barrier layer and an indium-containing insertion layer, wherein the indium-containing insertion layer is sandwiched between the indium-containing quantum well layer and the quantum barrier layer, and the content of indium in the indium-containing insertion layer is greater than that of the indium-containing insertion layer The content of indium in the indium-containing quantum well layer.

In the light-emitting device provided by the present application, the light-emitting device can emit light by arranging the base substrate, the first semiconductor layer, the light-emitting layer and the second semiconductor layer in sequence on the light-emitting device. Function. By arranging the light-emitting layer to be periodically overlapped by a plurality of the light-emitting units, the composite radiation efficiency can be increased, and the light-emitting efficiency of the light-emitting device can be improved. In addition, the present application inserts the indium-containing insertion layer with an indium content greater than the indium content in the indium-containing quantum well layer between the indium-containing quantum well layer and the quantum barrier layer of the light-emitting unit, and the indium-containing insertion layer is The tensile strain state introduced by the high indium composition in the indium-containing insertion layer can offset the compressive strain caused by lattice adaptation between the indium-containing quantum well layer and the quantum barrier layer, that is, the indium-containing quantum well layer can be weakened The problem of piezoelectric polarization caused by lattice adaptation with the quantum barrier layer increases the overlapping area of the wave functions of electrons and holes, and finally increases the radiation recombination probability of electrons and holes, thereby improving the light-emitting device. luminous efficiency.

Optionally, the indium-containing quantum well layer includes an indium gallium nitride layer, and the indium-containing insertion layer includes an aluminum indium nitride layer.

The indium gallium nitride layer can better confine the carriers in the light emitting unit, and can better realize the composite light emission of electrons and holes.

Optionally, the composition of the aluminum element in the aluminum indium nitride layer is between 75% and 85%, and the composition of the indium element is between 15% and 25%.

The ratio of the aluminum component to the indium component in the aluminum indium nitride layer enables the light-emitting unit to form a smooth and steep interface, and to form tensile stress in the light-emitting unit.

Optionally, the composition of indium element in the indium gallium nitride layer is between 5% and 20%.

The composition of indium in the indium gallium nitride layer is close to the composition of indium in the aluminum indium nitride layer, so that the lattice matching between the two can be better.

Optionally, the overlapping period of the light-emitting units is greater than or equal to six.

When the overlapping period of the light-emitting units is greater than or equal to six, the light-emitting device can better maintain its own optoelectronic properties.

Optionally, the light-emitting device further includes a flattening layer, the flattening layer is located between the first semiconductor layer and the light-emitting unit, the indium-containing quantum well layer is formed on the flattening layer, and the indium-containing quantum well layer is formed on the flattening layer. An indium insertion layer is formed on the indium-containing quantum well layer, and the quantum barrier layer is formed on the indium-containing insertion layer.

Optionally, the growth thickness h1 of the flattening layer satisfies 7nm≤h1≤15nm, and the growth thickness h2 of the indium-containing quantum well layer satisfies 3nm≤h2≤5nm.

Optionally, the thickness h3 of the indium-containing insertion layer satisfies 0.7nm≤h3≤1.5nm.

Optionally, the thickness h4 of the quantum barrier layer satisfies 6nm≤h4≤10nm.

A method for preparing a light-emitting device, comprising the following steps: providing a base substrate; growing a first semiconductor layer on the base substrate; growing a light-emitting unit on the first semiconductor layer; wherein, the light-emitting unit It includes an indium-containing quantum well layer, a quantum barrier layer, and an indium-containing insertion layer, the indium-containing insertion layer is sandwiched between the indium-containing quantum well layer and the quantum barrier layer, and the grown indium-containing insertion layer is The content of indium is greater than the content of indium in the grown indium-containing quantum well layer; the fabrication steps of the light-emitting unit are periodically repeated to form a light-emitting layer; a second semiconductor layer is formed on the light-emitting layer.

Through the method for preparing a light-emitting device provided in the present application, the above-mentioned light-emitting device can be produced correspondingly, and the light-emitting device can reduce the influence of the polarized electric field in the light-emitting layer and increase the wave between electrons and holes. The functions overlap to improve the recombination efficiency of carriers, thereby improving the luminous efficiency of the light-emitting device.

Optionally, the indium-containing quantum well layer includes an indium gallium nitride layer, and the indium-containing insertion layer includes an aluminum indium nitride layer; and fabricating a light-emitting unit on the first semiconductor layer includes: controlling a The indium gallium nitride layer is grown under a growth pressure; the growth pressure is adjusted to make the current growth pressure meet the growth requirements of the aluminum indium nitride layer, and the adjusted growth pressure of the aluminum indium nitride layer is controlled After the growth of the aluminum indium nitride layer is completed, the current growth pressure is adjusted again to meet the growth requirements of the quantum barrier layer; the quantum barrier layer is controlled to grow under the readjusted growth pressure.

When the indium gallium nitride layer, the aluminum indium nitride layer and the quantum barrier layer are grown respectively, the appropriate growth pressure needs to be adjusted to suit the indium gallium nitride layer and the aluminum indium nitride layer respectively and the growth requirements of the quantum barrier layer.

Optionally, the method further includes: in response to the adjusted growth pressure meeting the requirements of the aluminum indium nitride layer, controlling the adjusted growth pressure to remain stable for a preset time.

When growing the aluminum indium nitride layer, first maintaining the stability of the growth pressure for a preset time can make the growth effect of the aluminum indium nitride layer better, thereby ensuring the display effect of the light emitting layer.

Optionally, the step of adjusting the growth pressure to make the current growth pressure meet the growth requirements of the aluminum indium nitride layer includes: reducing the growth pressure to make the current growth pressure meet the growth of the aluminum indium nitride layer Require.

Since the growth pressure for growing the aluminum indium nitride layer is relatively small, the growth pressure needs to be reduced when the above-mentioned aluminum indium nitride layer is grown.

Optionally, before fabricating the light-emitting unit, a planarization layer is first grown on the first semiconductor layer, and then the indium gallium nitride layer is grown on the planarization layer, and then the indium gallium nitride layer is grown on the indium gallium nitride layer. The aluminum indium nitride layer is grown, and the quantum barrier layer is grown on the aluminum indium nitride layer.

Optionally, the growth pressure of the planarization layer and the indium gallium nitride layer is greater than 350 mbar.

Optionally, after growing the flattening layer and the indium gallium nitride layer, a first growth transition stage is reached, and after the growth pressure is reduced to less than 100 mbar, a first stable stage is reached, and the first stable stage is grown in the first stable stage. the aluminum indium nitride layer.

Optionally, after growing the aluminum indium nitride layer, a second growth transition stage is reached, and the growth pressure is transitioned from less than 100 mbar to more than 350 mbar and then a second stable stage is reached, and the second stable stage is grown in the second stable stage. the quantum barrier layer.

Optionally, the carrier gas of the aluminum indium nitride layer is nitrogen, and the content of nitrogen is at least 90%.

A light-emitting device, comprising a first semiconductor layer, a light-emitting layer and a second semiconductor layer that are sequentially stacked on a base substrate;

The light-emitting layer includes periodically overlapping light-emitting units, the light-emitting unit includes an indium-containing quantum well layer, a quantum barrier layer and an indium-containing insertion layer, the indium-containing quantum well layer is disposed adjacent to the first semiconductor layer, and the The quantum barrier layer is disposed close to the second semiconductor layer, the indium-containing insertion layer is sandwiched between the indium-containing quantum well layer and the quantum barrier layer, and the indium-containing insertion layer includes an aluminum indium nitride layer, And the content of indium element in the indium-containing insertion layer is greater than the content of indium element in the indium-containing quantum well layer.

beneficial effect

Description of drawings

In order to explain the technical solutions of the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings that need to be used in the implementation manner. As far as technical personnel are concerned, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a light-emitting device provided by the present application.

FIG. 2 is a schematic diagram of an embodiment of a light emitting device provided by the present application.

FIG. 3 is a schematic diagram of another embodiment of the light emitting device provided by the present application.

FIG. 4 is a flow chart of a method for fabricating a light-emitting device provided in the present application.

FIG. 5 is a sub-step flow chart of step S30 in the light-emitting device manufacturing method provided in FIG. 4 .

FIG. 6 is a schematic diagram of the growth pressure of the light-emitting device provided by the present application.

Description of reference numerals: 10-light-emitting device; 100-substrate substrate; 200-buffer layer; 300-first semiconductor layer; 400-electron injection layer; 500-light-emitting layer; 600-electron blocking layer; 700-hole injection layer; 800-second semiconductor layer; 510-leveling layer; 520-light-emitting unit; 521-indium-containing quantum well layer; 522-indium-containing insertion layer; 523-quantum barrier layer; 501-indium gallium nitride layer; 502- Aluminum Indium Nitride layer.

Embodiments of the present invention

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application.

Furthermore, the following descriptions of the various embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present application may be practiced. Directional terms mentioned in this application, such as "upper", "lower", "front", "rear", "left", "right", "inner", "outer", "side", etc., only Reference is made to the directions of the accompanying drawings, therefore, the directional terms used are for better and clearer description and understanding of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, in a specific orientation construction and operation, and therefore should not be construed as limitations on this application.

Referring to the schematic structural diagram of the light-emitting device 10 provided in the embodiment of the present application shown in FIG. 1 , a chip can be formed after the light-emitting device 10 is fabricated and processed, and a light-emitting diode is formed after the chip is packaged, and the formed light-emitting diode can realize Its display and lighting functions. The light-emitting unit of the existing light-emitting device 10 usually has a phenomenon of large lattice mismatch in the layer, which will cause a high compressive stress inside the light-emitting unit, thereby causing the phenomenon of energy band bending. At this time, the radiation recombination efficiency of the carriers in the light-emitting layer 500 is low, and the light-emitting efficiency of the light-emitting diode formed by the light-emitting layer 500 is correspondingly low.

The light-emitting device 10 provided in the present application includes a first semiconductor layer 300 , a light-emitting layer 500 , and a second semiconductor layer 800 that are sequentially stacked on the base substrate 100 . Please refer to FIG. 2 , wherein the light-emitting layer 500 includes periodically overlapping light-emitting units 520 , and the combined action of the first semiconductor layer 300 , the light-emitting layer 500 and the second semiconductor layer 800 can realize the light-emitting function of the light-emitting device 10 and emit light at the same time. The unit 520 can improve the luminous efficiency of the light emitting device 10 .

Specifically, the light emitting unit 520 includes an indium-containing quantum well layer 521 , a quantum barrier layer 523 , and an indium-containing insertion layer 522 disposed between the indium-containing quantum well layer 521 and the quantum barrier layer 523 . The indium-containing quantum well layer 521 is disposed close to the first semiconductor layer 300 , and the quantum barrier layer 523 is disposed close to the second semiconductor layer 800 . In addition, the content of indium in the indium-containing insertion layer 522 is greater than that in the indium-containing quantum well layer 521, and the tensile strain state introduced by the high indium composition in the indium-containing insertion layer 522 can offset the indium-containing quantum well layer 521 and the quantum well layer 521. Compressive strain of the barrier layer 523 due to lattice adaptation. The material of the first semiconductor layer 300 is undoped gallium nitride, which is mainly fabricated by high temperature growth. The light emitting layer 500 is located between the first semiconductor layer 300 and the second semiconductor layer 800 , and the second semiconductor layer 800 is ohmic The contact layer, the ohmic contact layer can form a good ohmic contact and is conducive to the input and output of current.

For an embodiment, please refer to FIG. 3 , before the light-emitting layer 500 is grown on the light-emitting unit 520 , a flattening layer 510 may be grown, that is, the flattening layer 510 is located between the first semiconductor layer 300 and the light-emitting unit 520 . The material of the flattening layer 510 is gallium nitride, and the lattice constant difference between the flattening layer 510 and the light emitting unit 520 is small, which can reduce the polarization electric field inside the light emitting layer 500 and increase the quantum efficiency inside the light emitting layer 500 . In the production process of the light-emitting layer 500 , a layer 521 containing an indium quantum well is first formed on the flattening layer 510 , then an indium-containing insertion layer 522 is formed on the indium-containing quantum well layer 521 , and finally an indium-containing insertion layer 522 is formed. A layer of quantum barrier layer 523 can form a light-emitting unit 520 on the leveling layer 510 . At this time, the indium-containing insertion layer 522 is sandwiched between the indium-containing quantum well layer 521 and the quantum barrier layer 523 , and the indium-containing quantum well layer 521 in the light-emitting unit 520 is located on the planarization layer 510 . The structure formed by the light-emitting unit 520 can reduce the lattice mismatch constant difference between the indium-containing quantum well layer 521 , the indium-containing insertion layer 522 and the quantum barrier layer 523 , thereby weakening the piezoelectric polarization inside the light-emitting unit 520 effect.

It should be pointed out that when the growth thickness h1 of the flattening layer 510 satisfies 7nm≤h1≤15nm, the flattening layer 510 grown under high temperature conditions can form a steep growth interface with the indium-containing quantum well layer 521, so that it can relatively well. The carriers are confined in the indium-containing quantum well layer 521, and the recombination light emission of electron holes is realized. The growth thickness h2 of the indium-containing quantum well layer 521 satisfies: 3nm≤h2≤5nm, the growth thickness h4 of the quantum barrier layer 523 satisfies: 6nm≤h4≤10nm, and the growth thickness of the indium-containing quantum well layer 521 and the quantum barrier layer 523 can be The movement trajectories of electrons and holes are respectively restricted, so that the effect of improving the composite light emission can be better achieved in the light-emitting layer 500 . The thickness h3 of the indium-containing insertion layer 522 satisfies: 0.7 nm≤h3≤1.5 nm. When growing the indium-containing insertion layer 522, the thickness of the indium-containing insertion layer 522 needs to be limited, and when the thickness of the indium-containing insertion layer 522 is less than 0.7 nm, the indium-containing insertion layer 522 itself cannot function. When the thickness of the insertion layer 522 is higher than 1.5 nm, the light emitting device 10 may easily cause defects during the fabrication process. Preferably, in order to enable the indium-containing insertion layer 522 to better play its role, its thickness h3 satisfies the condition: 1 nm≤h3≤1.5nm.

For an embodiment, please continue to refer to FIG. 3 , an electron injection layer 400 may also be provided between the first semiconductor layer 300 and the light emitting layer 500 . The electron injection layer 400 is located between the first semiconductor layer 300 and the light-emitting layer 500 , that is, the electron injection layer 400 is located between the first semiconductor layer 300 and the planarization layer 510 , and the planarization layer 510 is mainly fabricated on the electron on the injection layer 400 . The electron injection layer 400 is grown with silicon (Si), and the material is the electron injection layer 400 of gallium nitride. The silicon-doped electron injection layer 400 can provide more electrons for the light-emitting device 10, and the electron injection layer 400 can be increased by increasing the content of electrons. The recombination rate between electrons and holes is increased, thereby increasing the recombination rate of carriers and improving the luminous efficiency of the light-emitting device 10 .

Referring to FIG. 3 for another embodiment, a buffer layer 200 may also be disposed between the base substrate 100 and the first semiconductor layer 300 . The buffer layer 200, also known as the gallium nitride nucleation layer, is mainly grown on the sapphire substrate at low temperature. The materials of the buffer layer 200 and the first semiconductor layer 300 are both gallium nitride, and the first semiconductor layer 300 is mainly grown at high temperature. Fabricated on the buffer layer 200 .

For an embodiment, please continue to refer to FIG. 3 , an electron blocking layer 600 and a hole injection layer 700 are further provided between the light emitting layer 500 and the second semiconductor layer 800 , and the electron blocking layer 600 is located between the light emitting layer 500 and the hole injection layer 700 between. The electron blocking layer 600 and the hole injection layer 700 are located between the light emitting layer 500 and the second semiconductor layer 800, that is, the electron blocking layer 600 and the hole injection layer 700 are located between the light emitting unit 520 and the second semiconductor layer 800, and The electron blocking layer 600 is located between the light emitting unit 520 and the hole injection layer 700 , and the electron blocking layer 600 is fabricated on the last light emitting unit 520 . The electron blocking layer 600 can block the direct transition of electrons from the light emitting layer 500 to the second semiconductor layer 800 , thereby avoiding the loss of electrons caused thereby, and simultaneously affecting the light emitting frequency of the light emitting layer 500 . The hole injection layer 700 is a magnesium (Mg)-doped hole injection layer 700. The magnesium-doped hole injection layer 700 can provide more holes for the light-emitting device 10, and increasing the content of holes can increase the number of holes. The recombination rate between electrons and electrons can improve the efficiency of electron-to-hole transition.

The light-emitting device 10 provided by the present application realizes the light-emitting function of the light-emitting device 10 by sequentially arranging the base substrate 100 , the first semiconductor layer 300 , the light-emitting layer 500 and the second semiconductor layer 800 on the light-emitting device 10 . By arranging the light-emitting layer 500 to be periodically overlapped by a plurality of light-emitting units 520 , the compound radiation efficiency can be increased, and the light-emitting efficiency of the light-emitting device 10 can be improved. In addition, in the present application, an indium-containing insertion layer 522 with an indium content greater than that in the indium-containing quantum well layer 521 is inserted between the indium-containing quantum well layer 521 and the quantum barrier layer 523 of the light-emitting unit 520 , and the indium-containing insertion layer 522 has a high indium content. The tensile strain state introduced by the composition can offset the compressive strain caused by the lattice adaptation of the indium-containing quantum well layer 521 and the quantum barrier layer 523, that is, it can weaken the indium-containing quantum well layer 521 and the quantum barrier layer 523 due to lattice adaptation. The problem of piezoelectric polarization caused by the matching increases, thereby increasing the area of the overlapping region of the wave functions of electrons and holes, and finally the radiation recombination probability of electrons and holes increases, thereby improving the luminous efficiency of the light-emitting device 10 .

In one embodiment, the indium-containing quantum well layer 521 includes the indium gallium nitride layer 501 , and the indium-containing insertion layer 522 includes the aluminum indium nitride layer 502 .

Specifically, in this embodiment, the indium gallium nitride layer 501 can better confine the carriers in the light emitting unit 520, and can better realize the composite light emission of electrons and holes. In addition, the aluminum indium nitride layer 502 in the light-emitting layer 500 can make the light-emitting layer 500 add an aluminum composition on the basis of the original indium composition. In addition, a certain ratio of the indium component and the aluminum component can make the matching of lattice constants in the light emitting layer 500 better, thereby weakening the polarized electric field in the light emitting layer 500 and improving the radiation recombination efficiency of carriers.

In one embodiment, the composition of the aluminum element in the aluminum indium nitride layer 502 is between 75% and 85%, and the composition of the indium element is between 15% and 25%.

Specifically, in this embodiment, when the composition of aluminum in the aluminum indium nitride layer 502 is between 75% and 85%, the addition of the aluminum composition increases the tensile stress in the light-emitting unit 520, and the There is compressive stress in the structure without aluminum component. After adding aluminum component, tensile stress and compressive stress are generated in the existing structure at the same time, and then the tensile stress and compressive stress can cancel each other and realize the balance of pressure, so as to reduce the energy. With curved effect. And the higher the content of the aluminum component in the aluminum indium nitride layer 502, the better the blocking effect on electrons.

It should be pointed out that when the content of indium in the aluminum indium nitride 522 changes, the content of aluminum in the aluminum indium nitride 522 will also change correspondingly, that is, the content of aluminum is adaptive with the change of the content of indium changing. That is, when the composition of aluminum in the aluminum indium nitride layer 502 is between 75% and 85%, the content of indium is correspondingly between 15% and 25%.

In one embodiment, the composition of indium element in the indium gallium nitride layer 501 is between 5% and 20%.

Specifically, in this embodiment, since the composition of indium in the aluminum indium nitride layer 502 is controlled at 15% to 25%, the composition of indium in the indium gallium nitride layer 501 should be controlled within 5% to 20%. At this time, the composition of indium in the indium gallium nitride layer 501 is close to the composition of indium in the aluminum indium nitride layer 502, so that the lattice matching between the two is better, and the pressure between the two can be reduced. Electric polarization effect, thereby increasing the recombination efficiency of electrons and holes in space. And because the migration characteristics of the aluminum composition and the indium composition are significantly different, the light-emitting device 10 provided by the present application can easily realize a smooth surface layer and a steeper interface layer, so that electrons and holes can be better confined to In the multi-quantum light-emitting unit 520, radiation compound light emission is realized.

It should be pointed out that the strain state of the AlInN layer 502 can be adjusted according to the strain state of the quantum barrier layer 523, and the strain state of the indium composition can be changed from severe compressive strain to close to lattice matching, and then to tensile strain state. The tensile strain state introduced by the indium component in the aluminum indium nitride layer 502 can offset the compressive strain caused by the lattice mismatch of the indium-containing quantum well layer 521 and the quantum barrier layer 523, which can weaken the indium-containing quantum well layer 521 and the quantum barrier layer 523. The barrier layer 523 increases the area of the overlapping region of the electron and hole wave functions due to the piezoelectric polarization caused by the lattice mismatch.

In one embodiment, the overlapping period of the light emitting cells 520 is greater than or equal to six.

Specifically, in this embodiment, the light-emitting layer 500 in the present application is composed of a leveling layer 510 and at least six light-emitting units 520, and the at least six light-emitting units 520 are stacked in sequence. That is, a layer of indium-containing quantum well layer 521 , a layer of indium-containing insertion layer 522 , and a layer of quantum barrier layer 523 are sequentially fabricated on the leveling layer 510 to form a layer of light-emitting units 520 , and then repeat the fabrication of the light-emitting units 520 In the step, a new layer of indium-containing quantum well layer 521 is fabricated on the quantum barrier layer 523, and the overlapping fabrication of at least six light-emitting units 520 is completed in sequence. The material of the planarization layer 510 in the light-emitting layer 500 is gallium nitride, which is substantially the same material as the material of the quantum barrier layer 523 in the light-emitting unit 520 . Overlapping at least six layers of light-emitting units 520 can better ensure the optoelectronic properties of the light-emitting layer 500 . It should be mentioned that the overlapping number of the light emitting units 520 should be kept between six to ten layers. When the overlapping number of the light emitting units 520 is less than six layers, the photoelectric properties of the light emitting units 520 cannot be guaranteed. When the overlapping number of the light emitting units 520 is greater than ten layers, the thickness of the light emitting layer 500 will be too large, making it difficult to form on the light emitting layer 500 preset voltage difference. Preferably, the overlapping number of the light emitting units 520 is set to eight or nine layers.

It should be noted that the present application adopts the method of inserting an indium-containing insertion layer 522 between the indium-containing quantum well layer 521 and the quantum barrier layer 523 to prepare the light-emitting device 10 , but it is not limited to the embodiment shown in FIG. 2 . The arrangement method should include inserting an indium-containing insertion layer 522 in the light-emitting layer 500, and any arrangement between the indium-containing insertion layer 522, the indium-containing quantum well layer 521, and the quantum barrier layer 523, and in any arrangement. In all cases, the luminous efficiency of the light emitting device 10 can be improved.

The present application also relates to a method for preparing a light-emitting device 10 , please refer to FIG. 4 , including the following steps: S10 , providing a base substrate 100 .

Specifically, in this embodiment, the base substrate 100 is prepared for the subsequent growth of the first semiconductor layer 300 and other layer structures. The semiconductor layer of the light-emitting portion of an LED, a semiconductor laser, or the like is formed by growing crystals on the base substrate 100 . The used base substrate 100 is used according to the light emission wavelength of the LED.

S20, growing a first semiconductor layer 300 on the base substrate 100; specifically, in this embodiment, the first semiconductor layer 300 is an undoped gallium nitride layer, and the first semiconductor layer 300 is grown at a high temperature way of making. In one embodiment, the buffer layer 200 may also be grown on the base substrate 100 at a low temperature, and the undoped first semiconductor layer 300 may be grown on the buffer layer 200 at a high temperature. At this time, the buffer layer 200 is located on the base substrate 100 and the undoped between the first semiconductor layers 300 .

S30, growing a light-emitting unit 520 on the first semiconductor layer 300; wherein, the light-emitting unit 520 includes an indium-containing quantum well layer 521, a quantum barrier layer 523 and an indium-containing insertion layer 522, and the indium-containing insertion layer 522 is sandwiched between the indium-containing quantum well layers 521 Between the well layer 521 and the quantum barrier layer 523 , the content of indium in the grown indium-containing insertion layer 522 is greater than that in the grown indium-containing quantum well layer 521 .

Specifically, in this embodiment, the light emitting unit 520 includes an indium-containing quantum well layer 521 , a quantum barrier layer 523 , and an indium-containing insertion layer 522 disposed between the indium-containing quantum well layer 521 and the quantum barrier layer 523 . The content of indium in the indium-containing insertion layer 522 is greater than that in the indium-containing quantum well layer 521, and the tensile strain state introduced by the high indium composition in the indium-containing insertion layer 522 can offset the indium-containing quantum well layer 521 and the quantum barrier. Compressive strain of layer 523 due to lattice adaptation.

S40 , the manufacturing steps of the light-emitting unit 520 are periodically repeated to form a light-emitting layer 500 .

Specifically, in this embodiment, there are a plurality of light-emitting units 520 in the light-emitting layer 500 that are periodically and repeatedly grown, and the light-emitting units 520 fabricated by overlapping can better ensure the optoelectronic properties of the light-emitting layer 500 .

S50 , forming a second semiconductor layer 800 on the light emitting layer 500 .

Specifically, in this embodiment, the light-emitting layer 500 is located between the first semiconductor layer 300 and the second semiconductor layer 800 . The second semiconductor layer 800 in this step is also an ohmic contact layer, and the ohmic contact layer can form a good ohmic contact layer. contacts, and facilitates the input and output of current.

The method of the present application can be used to form the aforementioned light-emitting device 10 , and the combined action of the first semiconductor layer 300 , the light-emitting layer 500 and the second semiconductor layer 800 can realize the light-emitting function of the light-emitting device 10 , and the light-emitting unit 520 can improve the light-emitting function of the light-emitting device 10 . The luminous efficiency is reduced, and the polarization electric field inside the light-emitting device 10 is weakened, so as to improve the quantum efficiency in the light-emitting device 10 and further improve the luminous efficiency of the light-emitting diode.

5 , the indium-containing quantum well layer 521 includes an indium gallium nitride layer 501 , and the indium-containing insertion layer 522 includes an aluminum indium nitride layer 502 . A light-emitting unit 520 ″ is grown on the first semiconductor layer 300 , and further includes: S31 , controlling the growth of the indium gallium nitride layer 501 under a growth pressure; S32 , adjusting the growth pressure to make the current growth pressure match the aluminum indium nitride layer 502 and control the growth of the aluminum indium nitride layer 502 under the adjusted growth pressure; S33, after the growth of the aluminum indium nitride layer 502 is completed, adjust the current growth pressure again to meet the growth requirements of the quantum barrier layer 523; S34, the control quantum barrier layer 523 is grown under the adjusted growth pressure again.

Specifically, in this embodiment, referring to FIG. 6 , for the fabrication of the indium gallium nitride layer 501 , the aluminum indium nitride layer 502 and the quantum barrier layer 523 , the control of the growth pressure is particularly critical. In one embodiment, a planarization layer 510 is formed on the first semiconductor layer 300 before the aluminum indium nitride layer 502 is formed, and the growth stage of the planarization layer 510 is defined as a1, and the growth stage of the indium gallium nitride layer 501 is defined as a2, The first growth transition stage of the aluminum indium nitride layer 502 is b1, the growth stage of the aluminum indium nitride layer 502 is a3, the first stable stage is c1, the second growth transition stage of the aluminum indium nitride layer 502 is b2, the second The stable stage is c2, and the growth stage of the quantum barrier layer 523 is a4. And in this step, when the light-emitting unit 520 is fabricated on the first semiconductor layer 300, it is necessary to carry out the boosting and decreasing operations according to the growth pressure required by each layer structure, so that each layer structure can achieve its better performance. growth effect.

An embodiment further includes: in response to the adjusted growth pressure meeting the requirements of the aluminum indium nitride layer 502, controlling the adjusted growth pressure to remain stable for a predetermined time.

Specifically, in this embodiment, before growing the aluminum indium nitride layer 502, the growth pressure at this time needs to be kept stable for a predetermined period of time, and the growth pressure of the aluminum indium nitride layer 502 needs to be kept stable for a certain period of time. The stability of the growth pressure within the set time can make the growth effect of the aluminum indium nitride layer 502 better, thereby ensuring the display effect of the light emitting layer 500 . It should be pointed out that the pre-reaction in the light-emitting device 10 will be too strong due to the increase of the aluminum element in the light-emitting layer 500, so the growth pressure of the aluminum-indium-nitride layer 502 needs to be reduced in the production process to achieve a suitable nitrogen The growth environment of the aluminum indium layer 502 can be ensured, and the stability of its growth can be ensured, thereby ensuring a clearer light-emitting interface.

In one embodiment, for the above-mentioned step "response to the adjusted growth pressure meeting the requirements of the aluminum indium nitride layer 502, the adjusted growth pressure is controlled to remain stable for a predetermined time", including: reducing the growth pressure In order to make the current growth pressure meet the growth requirements of the aluminum indium nitride layer 502 .

Specifically, in this embodiment, please refer to FIG. 6 , because an indium gallium nitride layer 501 needs to be grown before the growth of the aluminum indium nitride layer 502 , and the growth pressure of the indium gallium nitride layer 501 is higher than that of the aluminum nitride layer. The growth pressure of the indium layer 502 is high. Therefore, the growth pressure in the growth environment needs to be reduced before growing the aluminum indium nitride layer 502 , and the reduced growth pressure can meet the growth requirements of the aluminum indium nitride layer 502 .

In one embodiment, the growth pressure of the indium gallium nitride layer 501 is greater than 350 mbar, the growth pressure of the aluminum indium nitride layer 502 is less than 100 mbar, and the growth pressure of the quantum barrier layer 523 is greater than 350 mbar.

Specifically, in this embodiment, please refer to FIG. 6 , the growth pressure during the growth of the planarization layer 510 and the indium-containing quantum well layer 521 is greater than 350 mbar, that is, the growth stage a1 of the planarization layer 510 in FIG. 6 and the indium-containing quantum well layer The growth stage a2 of the layer 521, and then the first growth transition stage b1 is reached. Since the aluminum element needs to be introduced when the aluminum indium nitride layer 502 is grown, after the indium-containing quantum well layer 521 is grown, the pressure of the reaction chamber needs to be reduced, The growth pressure at this time transitioned from more than 350 mbar to the growth pressure of less than 100 mbar in growth stage a3, and the transition time was between 70s and 100s. After the growth pressure is less than 100 mbar, the first stable stage c1 is reached, and the stable time is 20s-40s, and the aluminum indium nitride layer 502 is grown in this section. After growing the aluminum indium nitride layer 502, a quantum barrier layer 523 needs to be grown, and the growth pressure at this time needs to be transitioned from a growth pressure of less than 100 mbar to a growth pressure of more than 350 mbar, that is, the first step of the aluminum indium nitride layer 502 shown in FIG. 6 . The second growth transition stage b2, the transition time of this stage is between 30s and 70s, and a certain stabilization time is required before the quantum barrier layer 523 is grown on the aluminum indium nitride layer 502, that is, the second stable stage c2, and the second stable The stabilization time of the stage c2 is 10s-20s, and after stabilization, it reaches the growth stage a4 of the quantum barrier layer 523 . And when manufacturing the light-emitting device 10 in the present application, the growth pressure stage needs to be repeated at least six times to grow at least six layers of light-emitting units 520 .

On the other hand, in this embodiment, the carrier gas of the aluminum indium nitride layer 502 is nitrogen, and the content of nitrogen is at least 90%. The carrier gas can usually be nitrogen or hydrogen. However, in this method, the hydrogen content is too high, which is easy to react with the indium element, thereby affecting the function of the overall structure layer. Therefore, increasing the nitrogen content can effectively avoid the adverse effect of hydrogen on the structure. Preferably, the aluminum indium nitride layer 502 can be made of a carrier gas with a nitrogen content of more than 99%, and further, the aluminum indium nitride layer 502 can be made of a carrier gas with a nitrogen content of 100%.

The above is the implementation of the embodiments of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of the embodiments of the present application, several improvements and modifications can also be made. These improvements and modifications are also It is regarded as the protection scope of this application.

Claims

A light-emitting device, comprising a first semiconductor layer, a light-emitting layer and a second semiconductor layer stacked on a base substrate in sequence;

The light-emitting layer includes periodically overlapping light-emitting units, the light-emitting unit includes an indium-containing quantum well layer, a quantum barrier layer, and an indium-containing insertion layer, and the indium-containing insertion layer is sandwiched between the indium-containing quantum well layer and the indium-containing insertion layer. between the quantum barrier layers, and the content of indium element in the indium-containing insertion layer is greater than the content of indium element in the indium-containing quantum well layer.
The light emitting device of claim 1, wherein the indium-containing quantum well layer comprises an indium gallium nitride layer, and the indium-containing insertion layer comprises an aluminum indium nitride layer.
The light-emitting device according to claim 2, wherein the composition of the aluminum element in the aluminum indium nitride layer is between 75% and 85%, and the composition of the indium element is between 15% and 25%. .
The light-emitting device as claimed in claim 2, wherein the composition of the indium element in the indium gallium nitride layer is between 5% and 20%.
The light emitting device of claim 1, wherein an overlap period of the light emitting cells is greater than or equal to six.
The light emitting device of claim 1, wherein the light emitting device further comprises a flattening layer located between the first semiconductor layer and the light emitting unit, and the indium-containing quantum well layer is formed on On the leveling layer, the indium-containing insertion layer is formed on the indium-containing quantum well layer, and the quantum barrier layer is formed on the indium-containing insertion layer.
The light emitting device according to claim 6, wherein the growth thickness h1 of the planarization layer satisfies 7nm≤h1≤15nm, and the growth thickness h2 of the indium-containing quantum well layer satisfies 3nm≤h2≤5nm.
The light emitting device as claimed in claim 7, wherein the thickness h3 of the indium-containing insertion layer satisfies 0.7nm≤h3≤1.5nm.
The light emitting device as claimed in claim 7, wherein the thickness h4 of the quantum barrier layer satisfies 6nm≤h4≤10nm.
A method for preparing a light-emitting device, comprising the following steps:

providing a base substrate;

growing a first semiconductor layer on the base substrate;

A light-emitting unit is grown on the first semiconductor layer; wherein, the light-emitting unit includes an indium-containing quantum well layer, a quantum barrier layer and an indium-containing insertion layer, and the indium-containing insertion layer is sandwiched between the indium-containing quantum wells between the layer and the quantum barrier layer, and the content of indium in the grown indium-containing insertion layer is greater than the content of indium in the grown indium-containing quantum well layer;

periodically repeating the fabrication steps of the light-emitting unit to form a light-emitting layer; and

A second semiconductor layer is formed on the light-emitting layer.
The method for fabricating a light-emitting device as claimed in claim 10, wherein the indium-containing quantum well layer comprises an indium gallium nitride layer, the indium-containing insertion layer comprises an aluminum indium nitride layer; A light-emitting unit is fabricated on the layer, including:

controlling the indium gallium nitride layer to grow under a growth pressure;

adjusting the growth pressure to make the current growth pressure meet the growth requirements of the aluminum indium nitride layer, and controlling the aluminum indium nitride layer to grow under the adjusted growth pressure;

After completing the growth of the aluminum indium nitride layer, adjust the current growth pressure again to meet the growth requirements of the quantum barrier layer; and

The quantum barrier layer is controlled to grow under the readjusted growth pressure.
The method for fabricating a light-emitting device as claimed in claim 11, further comprising:

In response to the adjusted growth pressure meeting the requirements of the aluminum indium nitride layer, the adjusted growth pressure is controlled to remain stable for a predetermined time.
The method for fabricating a light-emitting device as claimed in claim 11, wherein the step of adjusting the growth pressure to make the current growth pressure meet the growth requirements of the aluminum indium nitride layer comprises:

The growth pressure is reduced so that the current growth pressure meets the growth requirements for the aluminum indium nitride layer.
The method for fabricating a light-emitting device according to claim 11, wherein before fabricating the light-emitting unit, a planarization layer is first grown on the first semiconductor layer, and then the indium gallium nitride layer is grown on the planarization layer , growing the aluminum indium nitride layer on the indium gallium nitride layer, and growing the quantum barrier layer on the aluminum indium nitride layer.
The method for fabricating a light emitting device according to claim 14, wherein the growth pressure of the planarization layer and the indium gallium nitride layer is greater than 350 mbar.
The method for manufacturing a light-emitting device according to claim 15, wherein a first growth transition stage is reached after growing the planarization layer and the indium gallium nitride layer, and a first stable stage is reached after the growth pressure is reduced to less than 100 mbar , growing the aluminum indium nitride layer in the first stable stage.
The method for fabricating a light-emitting device according to claim 16, wherein the second growth transition stage is reached after the growth of the aluminum indium nitride layer, and the second stable stage is reached after the growth pressure is transitioned from less than 100 mbar to more than 350 mbar , the quantum barrier layer is grown in the second stable stage.
The method for manufacturing a light-emitting device according to claim 11, wherein the carrier gas of the aluminum indium nitride layer is nitrogen, and the nitrogen content is at least 90%.
A light-emitting device, comprising a first semiconductor layer, a light-emitting layer and a second semiconductor layer that are sequentially stacked on a base substrate;

The light-emitting layer includes periodically overlapping light-emitting units, the light-emitting unit includes an indium-containing quantum well layer, a quantum barrier layer and an indium-containing insertion layer, the indium-containing quantum well layer is disposed adjacent to the first semiconductor layer, and the The quantum barrier layer is disposed close to the second semiconductor layer, the indium-containing insertion layer is sandwiched between the indium-containing quantum well layer and the quantum barrier layer, and the indium-containing insertion layer includes an aluminum indium nitride layer, And the content of indium element in the indium-containing insertion layer is greater than the content of indium element in the indium-containing quantum well layer.