CN111900240A - High-brightness LED and preparation method thereof - Google Patents

High-brightness LED and preparation method thereof Download PDF

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Publication number
CN111900240A
CN111900240A CN202010494780.5A CN202010494780A CN111900240A CN 111900240 A CN111900240 A CN 111900240A CN 202010494780 A CN202010494780 A CN 202010494780A CN 111900240 A CN111900240 A CN 111900240A
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layer
doped
nitride
heavy
light
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张宇
韩琳
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Shandong University
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Shandong University
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H01L33/40—Materials therefor
    • H01L33/405—Reflective materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0062—Processes for devices with an active region comprising only III-V compounds
    • H01L33/0075—Processes for devices with an active region comprising only III-V compounds comprising nitride compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/04—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
    • H01L33/06—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of group III and group V of the periodic system
    • H01L33/32—Materials of the light emitting region containing only elements of group III and group V of the periodic system containing nitrogen
    • H01L33/325—Materials of the light emitting region containing only elements of group III and group V of the periodic system containing nitrogen characterised by the doping materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
    • H01L2933/0008—Processes
    • H01L2933/0016—Processes relating to electrodes

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Led Devices (AREA)

Abstract

The invention discloses a high-brightness LED and a preparation method thereof, wherein the high-brightness LED comprises a substrate, wherein a buffer layer, a light-doped and heavy-doped nitride alternating layer, an MQW active layer and a p-type semiconductor layer are sequentially grown on the substrate, an n electrode is arranged on the exposed part of the upper surface of the light-doped and heavy-doped nitride alternating layer, and a p electrode is arranged on the p-type semiconductor layer; the light-doped and heavy-doped nitride alternating layers are alternately stacked low-porosity porous nitride layers and high-porosity porous nitride layers which are formed by the light-doped nitride layers and the heavy-doped nitride layers through electrochemical corrosion respectively. The high-brightness LED and the preparation method thereof disclosed by the invention can improve the luminous efficiency while reducing the cost, have high repeatability and are beneficial to practical application.

Description

High-brightness LED and preparation method thereof
Technical Field
The invention relates to the technical field of LEDs, in particular to a high-brightness LED and a preparation method thereof.
Background
Because the application of the group III nitride wide bandgap semiconductor material and device in the photoelectron and power electronic fields of illumination, display, communication, medical treatment and the like is wider, the nitride wide bandgap semiconductor material and device represented by the third generation semiconductor becomes a new generation field which is striven for by countries in the world. Because of the characteristics of small volume, low cost, good monochromaticity, high efficiency and the like, the LED has wide application prospect in the fields of illumination, display and optical communication, and becomes a hot spot for the research of the field of new generation electronic information technology-photoelectron.
The main research work on LEDs has focused on improving their luminous efficiency and reducing their cost. The method for improving the luminous efficiency of the LED by adopting simple growth and preparation processes is a very effective means for improving the performance of the LED and reducing the cost. One approach is to increase the luminous intensity of the LED by using light lost from the back surface by reflecting it back by epitaxy or making a highly reflective layer under the LED's light-emitting layer.
Currently, the adopted technology is to grow AlGaN/GaN or AlInN/GaN reflecting structure by epitaxy; there are also dielectric reflective layer or metal reflective layer structures used by substrate removal and lapping and polishing techniques. Devices fabricated by epitaxial growth techniques often require long growth times or stress due to lattice mismatch leads to DBR cracking; the process difficulty is increased while the epitaxial cost is increased; the photoelectric device is prepared by the laser stripping, metal bonding and mechanical polishing processes, so that the substrate polishing and thinning processes are very difficult to control, and the process cost is increased.
Therefore, the manufacturing process of the high-brightness LED is complex, high in cost and difficult to control due to the lack of the simple process for manufacturing the effective high-brightness LED so far. Therefore, it is necessary to develop a technology with simple growth and preparation process and low cost to realize the preparation of the high-brightness LED and overcome the bottleneck restricting the application thereof.
Disclosure of Invention
In order to solve the technical problems, the invention provides a high-brightness LED and a preparation method thereof, so as to achieve the purposes of reducing cost and improving luminous efficiency.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a high-brightness LED comprises a substrate, wherein a buffer layer, a light-doped and heavy-doped nitride alternating layer, an MQW active layer and a p-type semiconductor layer are sequentially grown on the substrate, an n electrode is arranged on the exposed part of the upper surface of the light-doped and heavy-doped nitride alternating layer, and a p electrode is arranged on the p-type semiconductor layer; the light-doped and heavy-doped nitride alternating layers are alternately stacked low-porosity porous nitride layers and high-porosity porous nitride layers which are formed by the light-doped nitride layers and the heavy-doped nitride layers through electrochemical corrosion respectively.
In the above scheme, the low-porosity porous nitride layer and the high-porosity porous nitride layer are alternately stacked to form a reflective structure, and the logarithm of the alternate structure is greater than or equal to 1.
In the above scheme, the substrate is sapphire, silicon carbide or glass; the buffer layer is made of one or a combination of AlN, GaN and AlGaN.
In the above scheme, the dopant of the lightly doped nitride layer and the heavily doped nitride layer is silicon or germanium, and the doping concentration of the heavily doped nitride layer is 5 × 1018～2×1020cm-3The doping concentration of the lightly doped nitride layer is 1 × 1018～5×1018cm-3。
In the above scheme, the n-electrode and the p-electrode are both metal electrodes, and are selected from one or any combination of Ti, Al, Ni, Au and Cr metals.
In the above scheme, the p-type semiconductor layer is magnesium-doped AlGaN, AlInN, AlInGaN or GaN, and the doping concentration of the magnesium-doped semiconductor layer is 2 × 1018～1×1020cm-3。
In the above scheme, the MQW active layer is InGaN, AlGaN, AlGaInN, or GaN.
In the above scheme, the nitride of the lightly doped nitride layer and the heavily doped nitride layer refers to GaN, InGaN, AlGaN, AlInN, or AlInGaN.
A preparation method of a high-brightness LED comprises the following steps:
(1) sequentially growing a buffer layer, a light-doped nitride alternating layer and a heavy-doped nitride alternating layer on the upper surface of the substrate, and sequentially growing an MQW active layer and a p-type semiconductor layer on the upper surface of the light-doped nitride alternating layer and the heavy-doped nitride alternating layer;
(2) forming an LED pattern by photoetching, dry etching and cleaning processes, and exposing partial light doped and heavy doped nitride alternating layers;
(3) corroding the light-doped and heavy-doped nitride alternating layers by adopting a selective electrochemical corrosion method to respectively form a low-porosity porous nitride layer and a high-porosity porous nitride layer which are alternately stacked, wherein the structure is a porous conductive reflection structure;
(4) and preparing an n electrode on the upper surface of the bare leaked light doped and heavy doped nitride alternating layer, and preparing a p electrode on the upper surface of the p-type semiconductor layer.
Through the technical scheme, the high-brightness LED and the preparation method thereof provided by the invention have the following beneficial effects:
1. the high-brightness LED has the advantages of simple structure, greatly shortened epitaxial process time, low cost, high repeatability and benefit for practical application.
2. An n electrode is manufactured on the light doped nitride alternating layer and the heavy doped nitride alternating layer, and the light doped nitride alternating layer and the heavy doped nitride alternating layer are directly used as an n-type conducting layer, so that the structure of the LED can be simplified; meanwhile, the lightly doped and heavily doped nitride alternating layers are prepared into the low-porosity porous nitride layer and the high-porosity porous nitride layer which are alternately stacked, and the porous nitride structure is used as a high-reflectivity reflection structure, so that light emitted by the MQW active region is directly emitted and then reflected out through the high-reflectivity porous structure, the optical path difference of LED reflected light is reduced, the light emitting efficiency of the LED is effectively improved, and the brightness is improved.
3. In addition, the porous nitride layer is formed by etching the alternating layers of the lightly doped nitride and the heavily doped nitride through a selective electrochemical corrosion technology, so that extra stress is not increased, the porous nitride layer has good conductivity by optimizing the doping concentration and the thickness of the porous nitride layer, and the photoelectric performance of the LED is improved while the difficulty of the preparation process is reduced.
4. The invention combines the n-type conducting layer and the reflecting layer into one layer, thereby effectively simplifying the structure of the LED, shortening the epitaxial process time of the LED and effectively reducing the cost of the epitaxial process.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.
Fig. 1 is a schematic structural diagram of a high-brightness LED according to an embodiment of the present invention;
FIG. 2 is a flowchart of a method for manufacturing a high-brightness LED according to an embodiment of the present invention;
FIG. 3 is a cross-sectional view of a scanning electron microscope of a high brightness LED;
FIG. 4 is a comparison of the emission spectra of an LED of the present invention having a porous nitride reflective structure and a conventional non-porous nitride reflective structure;
fig. 5 is a comparison graph of the photoelectric properties of an LED having a porous nitride reflective structure according to the present invention and a conventional non-porous nitride reflective structure.
In the figure, 1-substrate, 2-buffer layer, 3-alternating layers of lightly doped and heavily doped nitride, 4-MQW active layer, 5-p type semiconductor layer, 6-n electrode, 7-p electrode.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
The invention provides a high-brightness LED, which comprises a substrate 1, wherein a buffer layer 2, a light-doped and heavy-doped nitride alternating layer 3, an MQW active layer 4 and a p-type semiconductor layer 5 are sequentially grown on the substrate 1, an n electrode 6 is arranged on the exposed part of the upper surface of the light-doped and heavy-doped nitride alternating layer 3, and a p electrode 7 is arranged on the p-type semiconductor layer 5; as shown in fig. 3, the alternating lightly doped and heavily doped nitride layers 3 are alternately stacked low-porosity porous nitride layers and high-porosity porous nitride layers formed by electrochemical etching of the lightly doped nitride layers and the heavily doped nitride layers, respectively.
In this embodiment, the low porosity porous nitride layer and the high porosity porous nitride layer are alternately stacked to form a reflective structure, and the number of pairs of the alternate structures is equal to 5.
The substrate 1 is sapphire, silicon carbide or glass; the buffer layer 2 is made of one or a combination of AlN, GaN and AlGaN.
In this embodiment, the dopant of the lightly doped nitride layer and the heavily doped nitride layer is silicon,the doping concentration of the heavily doped nitride layer is 2 x 1019cm-3The doping concentration of the lightly doped nitride layer is 2 × 1018cm-3。
The n-electrode 6 and the p-electrode 7 are both metal electrodes, and are selected from one or any combination of Ti, Al, Ni, Au and Cr metals.
In this embodiment, the p-type semiconductor layer 5 is AlGaN doped with Mg at a doping concentration of 2 × 1019cm-3。
The MQW active layer 4 is InGaN or GaN.
In this embodiment, the nitride of the lightly doped nitride layer and the heavily doped nitride layer refers to GaN, InGaN, AlGaN, AlInN, or AlInGaN.
The preparation method of the high-brightness LED disclosed by the invention comprises the following steps of:
(1) sequentially growing a buffer layer 2, a lightly doped and heavily doped nitride alternating layer 3 on the upper surface of a substrate 1, and sequentially growing an MQW active layer 4 and a p-type semiconductor layer 5 on the upper surface of the lightly doped and heavily doped nitride alternating layer 3;
(2) forming an LED pattern by photoetching, dry etching and cleaning processes, and exposing partial light-doped and heavy-doped nitride alternating layers 3;
(3) corroding the light-doped and heavy-doped nitride alternating layers 3 by adopting a selective electrochemical corrosion method to respectively form a low-porosity porous nitride layer and a high-porosity porous nitride layer which are alternately stacked, wherein the structure is a porous conductive reflection structure;
(4) an n electrode 6 is prepared on the upper surface of the bare leaked alternating layers 3 of the lightly doped and heavily doped nitride, and a p electrode 7 is prepared on the upper surface of the p-type semiconductor layer 5.
As can be seen from fig. 4, the LED having the porous nitride reflective structure according to the present invention has an improved luminous intensity by 6 times as compared to the conventional LED having no porous nitride reflective structure, since the heavily doped nitride layer and the lightly doped nitride layer, which are alternately stacked, become the porous nitride reflective layer.
As can be seen from fig. 5, the LED luminous intensity obtained by the electrochemical etching is improved by 150%, and meanwhile, the electrical characteristics of the LED are almost unchanged after the porous nitride layer is formed by the electrochemical etching, which indicates that the photoelectric performance of the LED is greatly improved.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. A high-brightness LED comprises a substrate and is characterized in that a buffer layer, a light-doped and heavy-doped nitride alternating layer, an MQW active layer and a p-type semiconductor layer are sequentially grown on the substrate, an n electrode is arranged on the exposed part of the upper surface of the light-doped and heavy-doped nitride alternating layer, and a p electrode is arranged on the p-type semiconductor layer; the light-doped and heavy-doped nitride alternating layers are alternately stacked low-porosity porous nitride layers and high-porosity porous nitride layers which are formed by the light-doped nitride layers and the heavy-doped nitride layers through electrochemical corrosion respectively.
2. A high brightness LED according to claim 1, wherein said low porosity porous nitride layer and said high porosity porous nitride layer are alternately stacked to form a reflective structure, and the number of pairs of said alternate structure is 1 or more.
3. A high brightness LED according to claim 1, wherein said substrate is sapphire, silicon carbide or glass; the buffer layer is made of one or a combination of AlN, GaN and AlGaN.
4. A high brightness LED according to claim 1, wherein the dopant of said lightly doped nitride layer and said heavily doped nitride layer is silicon or germanium, and the dopant of said heavily doped nitride layer is heavily doped with silicon or germaniumThe doping concentration of the nitride layer is 5 × 1018～2×1020cm-3The doping concentration of the lightly doped nitride layer is 1 × 1018～5×1018cm-3。
5. A high brightness LED according to claim 1, wherein said n-electrode and p-electrode are both metal electrodes selected from one or any combination of Ti, Al, Ni, Au, Cr metals.
6. A high brightness LED according to claim 1 wherein said p-type semiconductor layer is mg-doped AlGaN, AlInN, AlInGaN or GaN, with mg-doping concentration of 2 x 1018～1×1020cm-3。
7. A high brightness LED according to claim 1, wherein said MQW active layer is InGaN, AlGaN, AlGaInN or GaN.
8. A high brightness LED according to claim 1, wherein the nitride of said lightly and heavily doped nitride layers is GaN, InGaN, AlGaN, AlInN or AlInGaN.
9. A preparation method of a high-brightness LED is characterized by comprising the following steps:
(1) sequentially growing a buffer layer, a light-doped nitride alternating layer and a heavy-doped nitride alternating layer on the upper surface of the substrate, and sequentially growing an MQW active layer and a p-type semiconductor layer on the upper surface of the light-doped nitride alternating layer and the heavy-doped nitride alternating layer;
(2) forming an LED pattern by photoetching, dry etching and cleaning processes, and exposing partial light doped and heavy doped nitride alternating layers;
(3) corroding the light-doped and heavy-doped nitride alternating layers by adopting a selective electrochemical corrosion method to respectively form a low-porosity porous nitride layer and a high-porosity porous nitride layer which are alternately stacked, wherein the structure is a porous conductive reflection structure;
(4) and preparing an n electrode on the upper surface of the bare leaked light doped and heavy doped nitride alternating layer, and preparing a p electrode on the upper surface of the p-type semiconductor layer.
CN202010494780.5A 2020-06-03 2020-06-03 High-brightness LED and preparation method thereof Pending CN111900240A (en)

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Application Number Priority Date Filing Date Title
CN202010494780.5A CN111900240A (en) 2020-06-03 2020-06-03 High-brightness LED and preparation method thereof

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CN111900240A true CN111900240A (en) 2020-11-06

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