CN218039251U

CN218039251U - LED epitaxial wafer and LED light-emitting diode

Info

Publication number: CN218039251U
Application number: CN202221973593.6U
Authority: CN
Inventors: 黄星; 曾家明; 郑文杰; 程龙; 高虹; 刘春杨; 胡加辉
Original assignee: Jiangxi Zhao Chi Semiconductor Co Ltd
Current assignee: Jiangxi Zhao Chi Semiconductor Co Ltd
Priority date: 2022-07-28
Filing date: 2022-07-28
Publication date: 2022-12-13
Anticipated expiration: 2032-07-28

Abstract

The utility model provides a LED epitaxial wafer and LED emitting diode, including the substrate and in proper order range upon range of in buffer layer, N type semiconductor layer, luminescent layer and P type semiconductor layer on the substrate, wherein: the light emitting layer comprises a plurality of groups of light emitting sublayers sequentially stacked on the N-type semiconductor layer, each group of light emitting sublayers comprises an InGaN quantum well layer, an AlInGaN insertion layer and an AlGaN quantum barrier layer which are sequentially stacked, and the InGaN quantum well layer in each group of light emitting sublayers is closest to the N-type semiconductor layer. The utility model provides a LED epitaxial wafer and LED emitting diode improves the lattice defect of the quantum well luminescent layer among the traditional LED emitting diode, and then improves the crystal growth quality of quantum well luminescent layer.

Description

LED epitaxial wafer and LED light-emitting diode

Technical Field

The utility model relates to the field of semiconductor technology, in particular to LED epitaxial wafer and LED emitting diode.

Background

At present, light emitting diodes have been widely applied in the solid state lighting field and the display field, and attract more and more people to pay attention. Light emitting diodes have been produced industrially and are used in backlights, illuminations, landscape lamps, etc.

Epitaxial growth of GaN-based materials is a core technology for developing GaN-based high-brightness LEDs and all-solid-state semiconductor white light illumination light sources, LED light-emitting diodes still mainly adopt gallium indium nitride/gallium nitride multi-quantum structures, but the reason that the quality of light-emitting layer quantum wells (MQW) of light-emitting areas is difficult to grow is that the dislocation density of the MQW is relatively high, and stress and polarization electric fields generated by lattice mismatch exist between the barriers and the wells, so that the radiation recombination efficiency is relatively low. Therefore, it is necessary and challenging to reduce lattice defects in the quantum well light emitting layer to improve the crystal quality of the quantum well light emitting layer, thereby producing higher quality GaN material with fewer defects.

SUMMERY OF THE UTILITY MODEL

Based on this, the utility model aims at providing a LED epitaxial wafer and LED emitting diode to improve the lattice defect of the quantum well luminescent layer among the traditional LED emitting diode, and then improve the crystal growth quality of quantum well luminescent layer.

An LED epitaxial wafer comprises a substrate, and a buffer layer, an N-type semiconductor layer, a light emitting layer and a P-type semiconductor layer which are sequentially stacked on the substrate, wherein:

the light emitting layer comprises a plurality of groups of light emitting sublayers sequentially stacked on the N-type semiconductor layer, each group of light emitting sublayers comprises an InGaN quantum well layer, an AlInGaN insertion layer and an AlGaN quantum barrier layer which are sequentially stacked, and the InGaN quantum well layer in each group of light emitting sublayers is closest to the N-type semiconductor layer.

In conclusion, according to the utility model provides a LED epitaxial wafer, the multilayer luminescence sublayer structure through new design, every group luminescence sublayer all includes InGaN quantum well layer, alInGaN inserted layer and AlGaN quantum barrier layer that stacks gradually, because the lattice constant and the forbidden band width of AlInGaN inserted layer all are in between InGaN quantum well layer and the AlGaN quantum barrier layer to can reduce the lattice mismatch on InGaN quantum well layer and AlGaN quantum barrier layer, improve the crystal quality of luminescent layer, thereby improve electron hole's recombination efficiency.

Furthermore, the thickness of the InGaN quantum well layer is 2-5 nm, the thickness of the AlInGaN insertion layer is 2-5 nm, and the thickness of the AlGaN quantum barrier layer is 5-15 nm.

Further, the light-emitting layer comprises 3-8 groups of light-emitting sub-layers.

Further, the buffer layer comprises a first buffer sub-layer, a second buffer sub-layer and a third buffer sub-layer which are sequentially stacked, the first buffer sub-layer and the second buffer sub-layer are AlN thin film layers, and the third buffer sub-layer is an AlGaN thin film layer.

Further, the thickness of the first buffer sublayer is 10-20 nm, the thickness of the second buffer sublayer is 30-50 nm, and the thickness of the AlGaN thin film layer is 5-10 nm.

The LED light-emitting diode further comprises a stress release layer arranged between the N-type semiconductor layer and the light-emitting layer, the stress release layer comprises a plurality of groups of stress release sublayers sequentially laminated on the N-type semiconductor layer, each group of stress release sublayers comprises a first GaN thin film layer, an InGaN thin film layer and a second GaN thin film layer which are sequentially laminated, and the first GaN thin film layer in each group of stress release sublayers is closest to the N-type semiconductor layer.

Further, the thickness of the second GaN thin film layer in the stress release sublayer closer to the N-type semiconductor layer is smaller.

Further, the thickness of the second GaN thin film layer is 3-10 nm.

Furthermore, the stress release layer comprises 2-8 groups of stress release sublayers.

On the other hand, the utility model also provides a LED, including foretell LED epitaxial wafer.

Drawings

Fig. 1 is a schematic structural diagram of an LED epitaxial wafer according to an embodiment of the present invention.

Description of the main element symbols:

substrate	10	Buffer layer	20
				N-type semiconductor layer	30	Luminescent sublayer	401
P-type semiconductor layer	50	InGaN quantum well layer	4011
				AlInGaN insertion layer	4012	AlGaN quantum barrier layer	4013
A first buffer sublayer	201	A second buffer sublayer	202
				Third buffer sublayer	203	Stress release sublayer	601
A first GaN thin film layer	6011	InGaN thin film layer	601
				Second GaN thin film layer	601

The following detailed description of the invention will be further described in conjunction with the above-identified drawings.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. Several embodiments of the invention are presented in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, a schematic structural diagram of an LED epitaxial wafer according to a first embodiment of the present invention is shown, the LED epitaxial wafer includes a substrate 10, and a buffer layer 20, an N-type semiconductor layer 30, a light emitting layer, and a P-type semiconductor layer 50 sequentially stacked on the substrate 10, wherein:

in order to solve the problem that the radiation recombination efficiency of a conventional light emitting layer is low due to stress and a polarization electric field generated by lattice mismatch between a barrier and a well, the light emitting layer in the embodiment includes a plurality of groups of light emitting sub-layers 401 sequentially stacked on the N-type semiconductor layer 30, each group of the light emitting sub-layers 401 includes an InGaN quantum well layer 4011, an AlInGaN insertion layer 4012 and an AlGaN quantum barrier layer 4013 sequentially stacked, the InGaN quantum well layer 4011 in each group of the light emitting sub-layers 401 is closest to the N-type semiconductor layer 30, and by designing a brand new light emitting layer, since the lattice constant and the forbidden bandwidth of the AlInGaN insertion layer 4012 in the light emitting layer are both between the InGaN quantum well layer 4011 and the AlGaN quantum barrier layer 4013, the lattice mismatch of the InGaN quantum well layer 4011 and the AlGaN quantum barrier layer 4013 can be reduced, the crystal quality of the light emitting layer is improved, and the recombination efficiency of electron holes is improved.

Further, in the present embodiment, the light emitting layer includes 3 to 8 sets of light emitting sublayers 401, and for each set of light emitting sublayers 401, an InGaN quantum well layer 4011 having a thickness of 2 to 5nm, such as 2nm, 3nm, or 5nm, etc., an AlInGaN insertion layer 4012 having a thickness of 2 to 5nm, such as 2nm, 3nm, or 5nm, etc., and an AlGaN quantum barrier layer 4013 having a thickness of 5 to 15nm, such as 5nm, 10nm, or 15nm, etc., are included.

It should be noted that, in all the light emitting sub-layers 401, the In content of the InGaN quantum well layer 4011 and the AlInGaN insertion layer 4012 In the light emitting sub-layer 401 closer to the stress relief layer is higher, wherein the In content of the InGaN quantum well layer 4011 is In a range of 0.2 to 0.5, and the In content of the AlInGaN insertion layer 4012 is In a range of 0.05 to 0.2.

Specifically, the buffer layer 20 further includes a first buffer sublayer 201, a second buffer sublayer 202, and a third buffer sublayer 203, which are sequentially stacked, where the first buffer sublayer 201 and the second buffer sublayer 202 are both AlN thin film layers, the third buffer sublayer 203 is an AlGaN thin film layer, in this embodiment, the growth temperature of the second buffer sublayer 202 is higher than the growth temperature of the first buffer sublayer 201, the thickness of the first buffer sublayer 201 is 10 to 20nm, for example, 10nm, 15nm, or 20nm, and the like, the thickness of the second buffer sublayer 202 is 30 to 50nm, for example, 30nm, 40nm, or 50nm, and the thickness of the AlGaN thin film layer is 5 to 10nm, for example, 5nm, 8nm, or 10nm, and the like. The first buffer sublayer 201 and the second buffer sublayer 202 are arranged, so that the problem of back fusion of the substrate 10 and the GaN epitaxial layer can be reduced, and the problem of lattice mismatch between the substrate 10 and the subsequent epitaxial layer can be reduced through buffer transition of the third buffer sublayer 203, so that the purpose of improving the growth quality of the epitaxial layer is achieved.

It can be understood that the LED epitaxial wafer further includes a stress release layer disposed between the N-type semiconductor layer 30 and the light emitting layer, that is, the stress release layer is stacked on the N-type semiconductor layer 30, the stress release layer includes a plurality of stress release sublayers 601 sequentially stacked on the N-type semiconductor layer 30, each of the stress release sublayers 601 includes a first GaN thin film layer 6011, an InGaN thin film layer 6012, and a second GaN thin film layer 6013 sequentially stacked, the first GaN thin film layer 6011 In each of the stress release sublayers 601 is closest to the N-type semiconductor layer 30, in this embodiment, the first GaN thin film layer 6011 is an N-type doped layer, and the second GaN thin film layer 6013 is an undoped layer, in all the stress release sublayers 601, the higher the N-type doping concentration of the first GaN thin film layer 6011 In the stress release sublayer 601 closer to the N-type semiconductor layer 30 is, the higher the In content of the InGaN 6012 In the stress release sublayer 601 closer to the N-type semiconductor layer 30 is, and the thickness of the second GaN thin film layer 6013 In the stress release sublayer 601 closer to the N-type semiconductor layer 30 is smaller. Specifically, the first GaN thin film layer 6011 is doped with an Si element, the doped Si concentration is 1E18 to 5E18 atoms/cm3, the In content of the InGaN thin film layer 6012 is 0.2 to 0.5, and the thickness of the second GaN thin film layer 6013 is 3 to 10nm.

Through the stress release layer, the influence of stress caused by epitaxial growth on the growth quality deterioration of a subsequent light emitting layer can be relieved, the electron migration quantity can be additionally provided through the N-type doped first GaN thin film layer 6011, the electron hole recombination probability in the light emitting layer can be improved, the current expansion performance can be improved, the lattice mismatch defect of the stress release layer and a quantum well layer in the light emitting layer is relieved through the InGaN thin film layer 6012, the growth quality of the epitaxial layer is improved, and the impurity atoms are prevented from entering the light emitting layer through the undoped second GaN thin film layer 6013, so that the electron hole recombination efficiency in the light emitting layer is prevented from being reduced by the impurity atoms.

In conclusion, according to the utility model provides a LED epitaxial wafer, the multilayer luminescence sublayer structure through the new design, every group luminescence sublayer all includes InGaN quantum well layer, alInGaN inserted layer and the AlGaN quantum barrier layer that stacks gradually, because the lattice constant and the forbidden band width of AlInGaN inserted layer all are in between InGaN quantum well layer and the AlGaN quantum barrier layer to can reduce the lattice mismatch of InGaN quantum well layer and AlGaN quantum barrier layer, improve the crystal quality of luminescent layer, thereby improve electron hole's recombination efficiency. In addition, through the buffer layer of design, through the buffer layer of new design, the buffer layer includes the first buffering sublayer, second buffering sublayer and third buffering sublayer that stack gradually, first buffering sublayer is the AlN thin layer, the second buffering sublayer is the AlN thin layer that growth temperature is higher than first buffering sublayer, the third buffering sublayer is the AlGaN thin layer, through the AlN thin layer of high and low temperature, can reduce the problem of melting back of substrate and GaN epitaxial layer to through the buffering transition of AlGaN thin layer, can reduce the lattice mismatch of substrate and follow-up epitaxial layer, improve the long brilliant quality of epitaxial layer. In addition, the newly designed stress release layer can relieve the influence of stress caused by epitaxial growth on the deterioration of the growth quality of a subsequent light-emitting layer.

Another aspect of the present invention is to provide an LED light emitting diode, which includes the LED epitaxial wafer in the above embodiments, so that the LED light emitting diode has all the advantages of the LED epitaxial wafer, which will not be described in detail herein.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An LED epitaxial wafer is characterized by comprising a substrate, and a buffer layer, an N-type semiconductor layer, a light emitting layer and a P-type semiconductor layer which are sequentially stacked on the substrate, wherein:

2. The LED epitaxial wafer of claim 1, wherein the InGaN quantum well layer has a thickness of 2-5 nm, the AlInGaN insertion layer has a thickness of 2-5 nm, and the AlGaN quantum barrier layer has a thickness of 5-15 nm.

3. The LED epitaxial wafer of claim 2, wherein the light emitting layer comprises 3-8 groups of the light emitting sublayers.

4. The LED epitaxial wafer according to claim 1, wherein the buffer layer comprises a first buffer sub-layer, a second buffer sub-layer and a third buffer sub-layer which are sequentially stacked, the first buffer sub-layer and the second buffer sub-layer are AlN thin film layers, and the third buffer sub-layer is an AlGaN thin film layer.

5. The LED epitaxial wafer according to claim 4, wherein the thickness of the first buffer sub-layer is 10-20 nm, the thickness of the second buffer sub-layer is 30-50 nm, and the thickness of the AlGaN thin film layer is 5-10 nm.

6. The LED epitaxial wafer of claim 1, further comprising a stress release layer disposed between the N-type semiconductor layer and the light emitting layer, wherein the stress release layer comprises a plurality of stress release sublayers sequentially stacked on the N-type semiconductor layer, each stress release sublayer comprises a first GaN thin film layer, an InGaN thin film layer, and a second GaN thin film layer sequentially stacked, and the first GaN thin film layer in each stress release sublayer is closest to the N-type semiconductor layer.

7. The LED epitaxial wafer of claim 6, wherein the thickness of the second GaN thin film layer in the stress relieving sublayer closer to the N-type semiconductor layer is smaller.

8. The LED epitaxial wafer of claim 7, wherein the thickness of the second GaN thin film layer is 3-10 nm.

9. The LED epitaxial wafer of claim 8, wherein the stress relief layer comprises 2-8 groups of stress relief sublayers in total.

10. An LED light emitting diode comprising the LED epitaxial wafer of any one of claims 1 to 9.