CN114023857B - LED epitaxial structure and preparation method thereof - Google Patents
LED epitaxial structure and preparation method thereof Download PDFInfo
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- 238000005260 corrosion Methods 0.000 claims abstract description 15
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- 229910001218 Gallium arsenide Inorganic materials 0.000 claims description 10
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- 238000001451 molecular beam epitaxy Methods 0.000 claims description 3
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers 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 having potential barriers 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 Table
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers 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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers 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 having potential barriers 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
- H01L33/12—Semiconductor devices having potential barriers 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 stress relaxation structure, e.g. buffer layer
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers 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 having potential barriers 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
- H01L33/14—Semiconductor devices having potential barriers 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 carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
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Abstract
The invention provides an LED epitaxial structure and a preparation method thereof, wherein the LED epitaxial structure sequentially comprises the following components from bottom to top: the semiconductor device comprises a bottom buffer layer, a corrosion stop layer, a first type semiconductor layer, an active layer and a second type semiconductor layer which are positioned on a substrate, wherein the first type semiconductor layer sequentially comprises a first type window layer and a first type limiting layer from bottom to top, the first type window layer is made of AlGaAs and is a structural layer with gradually changed Al components, and the thickness of the first type window layer is 1.5-8 mu m. According to the invention, the light emitting efficiency of the LED chip can be improved, the working voltage of the LED chip can be reduced, and the high-temperature aging stability of the LED chip can be improved by forming the first window layer with gradually changed Al components.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to an LED epitaxial structure and a preparation method thereof.
Background
The light emitting diode (LED, light Emitting Diode) is a semiconductor solid light emitting device, has the advantages of simple structure, light weight, no pollution and the like, has been widely applied to a plurality of fields such as digital, display, illumination, plant engineering and the like, is called an environment-friendly and energy-saving green illumination light source, and has a huge business opportunity. The infrared light-emitting diode is an important light-emitting diode, and is widely applied to the fields of remote control, vehicle sensing, closed-circuit television and the like, and the epitaxial structure of the infrared light-emitting diode is a basic structure for preparing the infrared light-emitting diode.
Aging at high temperatures and high currents over a long period of time can result in excessive junction temperatures of the LED chip, due to the slight lattice mismatch between the epitaxial structural layers, a large number of structural defects such as dislocations are formed at the interfaces between the layers. At higher temperatures, these defects can proliferate and propagate rapidly until they invade the light-emitting region, forming a large number of non-radiative recombination centers, severely reducing the injection efficiency and light-emitting efficiency of the light-emitting diode.
Disclosure of Invention
The invention provides an LED epitaxial structure and a preparation method thereof, which are used for improving the light emitting efficiency of an LED chip, reducing the working voltage of the LED chip and improving the high-temperature aging stability of the LED chip.
To achieve the above and other related objects, the present invention provides an LED epitaxial structure comprising, in order from bottom to top: the semiconductor device comprises a bottom buffer layer, a corrosion stop layer, a first type semiconductor layer, an active layer and a second type semiconductor layer which are positioned on a substrate, wherein the first type semiconductor layer sequentially comprises a first type window layer and a first type limiting layer from bottom to top, the first type window layer is made of AlGaAs and is a structural layer with gradually changed Al components, and the thickness of the first type window layer is 1.5-8 mu m.
Optionally, the first window layer includes a single-layer structure or a multi-period structure formed by the first structure layer, and the period number k ranges from 2 to 30.
Optionally, the first structural layer is Al x Ga 1-x As, and x is in the range of 0.05-0.30.
Optionally, the first window layer includes a two-layer structure formed by a first structural layer and a second structural layer or a multi-period structure formed by alternately stacking the first structural layer and the second structural layer, and the period number k ranges from 2 to 30.
Optionally, the first structural layer is Al a Ga 1-a As, the second structural layer is Al m Ga 1-m As, and m is more than or equal to 0.05 and less than or equal to 0.30; a is more than or equal to 0.05 and less than or equal to 0.30.
Optionally, the gradual change mode of the Al component in the first type window layer includes one or any combination of a linear gradual change mode, a nonlinear gradual change mode and a stepwise change mode.
Optionally, the gradual change mode of the Al component in the linear gradual change is a linear gradual change from large to small or a linear gradual change from small to large in a direction from the first type window layer to the first type limiting layer.
Optionally, in the same period, the difference between the maximum value and the minimum value of the Al component a and the Al component m in the first structural layer and the second structural layer is greater than 0.15.
Optionally, the first window layer is doped with Si, and the doping concentration of Si is 0.7E18-5E 18cm -3 。
Optionally, the first type semiconductor layer further includes a first type ohmic contact layer, and the first type ohmic contact layer is located between the corrosion cut-off layer and the first type window layer.
Optionally, the second semiconductor layer includes, in order from bottom to top: a second type limiting layer, a second type window layer and a second type ohmic contact layer.
Optionally, the first type semiconductor layer is an N type semiconductor layer, and the second type semiconductor layer is a P type semiconductor layer.
Alternatively, the substrate includes a GaAs substrate or a Si substrate.
To achieve the above object and other related objects, the present invention also provides a method for manufacturing an LED epitaxial structure, comprising the steps of:
providing a substrate;
sequentially growing a bottom buffer layer, a corrosion cut-off layer and a first type semiconductor layer on the substrate, wherein the first type semiconductor layer sequentially comprises a first type window layer and a first type limiting layer from bottom to top, the first type window layer is made of AlGaAs and is a structural layer with gradually changed Al components, and the thickness of the first type window layer is 1.5-8 mu m;
and sequentially growing an active layer and a second type semiconductor layer on the first type semiconductor layer.
Optionally, the first window layer includes a single-layer structure or a multi-period structure formed by the first structure layer, and the period number k ranges from 2 to 30.
Optionally, the first structural layer is Al x Ga 1-x As, and x is in the range of 0.05-0.30.
Optionally, the first window layer includes a two-layer structure formed by a first structural layer and a second structural layer or a multi-period structure formed by alternately stacking the first structural layer and the second structural layer, and the period number k ranges from 2 to 30.
Optionally, the first structural layer is Al a Ga 1-a As, the second structural layer is Al m Ga 1-m As, and m is more than or equal to 0.05 and less than or equal to 0.30; a is more than or equal to 0.05 and less than or equal to 0.30.
Optionally, the gradual change mode of the Al component in the first type window layer includes one or any combination of a linear gradual change mode, a nonlinear gradual change mode and a stepwise change mode.
Optionally, the gradual change mode of the Al component in the linear gradual change is a linear gradual change from large to small or a linear gradual change from small to large in a direction from the first type window layer to the first type limiting layer.
Optionally, in the same period, the difference between the maximum value and the minimum value of the Al component a and the Al component m in the first structural layer and the second structural layer is greater than 0.15.
Optionally, the first window layer is doped with Si, and the doping concentration of Si is 0.7E18-5E 18cm -3 。
Optionally, the first type semiconductor layer further includes a first type ohmic contact layer, and the first type ohmic contact layer is located between the corrosion cut-off layer and the first type window layer.
Optionally, the second semiconductor layer includes, in order from bottom to top: a second type limiting layer, a second type window layer and a second type ohmic contact layer.
Optionally, the first type semiconductor layer is an N type semiconductor layer, and the second type semiconductor layer is a P type semiconductor layer.
Alternatively, the substrate includes a GaAs substrate or a Si substrate.
Optionally, the preparation process of the epitaxial structure is any one of an MOCVD process, a molecular beam epitaxy process, an HVPE process, a plasma-assisted chemical vapor deposition process and a sputtering process.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
according to the invention, the first window layer with gradually changed Al components is adopted, and the layer structure is formed into a graded refractive index structure by changing the Al components, so that the internal reflection loss of the LED epitaxial structure can be reduced, the emergent angle of emergent light of the LED epitaxial structure is increased, more light can be coupled out, the emergent light efficiency of the LED chip is improved, and the luminous efficiency of the LED chip is further improved; meanwhile, due to gradual change of the Al component, the working voltage of the LED chip can be effectively reduced, and the performance of the LED chip is improved.
Further, aging at high temperatures and high currents over a long period of time can result in excessive junction temperatures of the LED chip, resulting in a large number of structural defects such as dislocations at the interfaces between the layers due to the slight lattice mismatch between the epitaxial structural layers. At higher temperatures, these defects can proliferate and propagate rapidly until they invade the light-emitting region, forming a large number of non-radiative recombination centers, severely reducing the injection efficiency and light-emitting efficiency of the light-emitting diode. The first type window layer with gradually changed Al components is adopted, so that the stress of the epitaxial structure under high-temperature aging can be effectively relieved, the derivation of defects is reduced, and the aging stability of the LED chip under high temperature is effectively improved.
Further, the thickness of the first type window layer is 1.5 μm to 8 μm. If the thickness of the first window layer is too thin, coarsening is not facilitated, and the brightness of the LED chip is low; if the thickness of the first type window layer is too thick, the voltage of the LED chip is too high and the light absorption brightness is low (the light efficiency is low), so that a good current expansion effect and a coarsening effect can be ensured by a proper thickness, and high photoelectric efficiency is achieved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.
Fig. 1 is a schematic structural diagram of an LED epitaxial structure according to a first embodiment of the present invention;
FIG. 2 is a schematic diagram of a first window layer according to a second embodiment of the present invention;
FIG. 3 is a flow chart of a method of fabricating an LED epitaxial structure according to an embodiment of the present invention;
in the figures 1 to 2 of the drawings,
101-substrate, 102-bottom buffer layer, 103-etch stop layer, 201-ohmic contact layer of the first type, 202-window layer of the first type, 203-confinement layer of the first type, 204-active layer, 205-confinement layer of the second type, 206-window layer of the second type, 207-ohmic contact layer of the second type, 2021-first structural layer, 2022-second structural layer.
Detailed Description
The LED epitaxial structure and the method for manufacturing the same according to the present invention are described in further detail below with reference to the accompanying drawings and specific examples. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the invention.
Before the description of the embodiments according to the present invention, the following will be described in advance. First, in the present specification, when only "GaInP" is labeled, the chemical composition ratio of the sum of Ga and In to P is 1:1, and the ratio of Ga to In is not fixed.
Example 1
Fig. 1 is a schematic structural diagram of an LED epitaxial structure of the present embodiment. Referring to fig. 1, the LED epitaxial structure sequentially includes, from bottom to top: the semiconductor device comprises a bottom buffer layer 102, a corrosion cut-off layer 103, a first type semiconductor layer, an active layer 204 and a second type semiconductor layer which are positioned on a substrate 101, wherein the first type semiconductor layer sequentially comprises a first type window layer 202 and a first type limiting layer 203 from bottom to top, and the first type window layer 202 is a structural layer with gradually changed Al components.
The first type semiconductor layer further includes a first type ohmic contact layer 201, and the first type ohmic contact layer 201 is located between the corrosion cut-off layer 103 and the first type window layer 202.
The second type semiconductor layer comprises the following components in sequence from bottom to top: a second type confinement layer 205, a second type window layer 206, and a second type ohmic contact layer 207.
The polarity of the first type semiconductor layer is opposite to that of the second type semiconductor layer, for example, the first type semiconductor layer is an N type semiconductor layer, and the corresponding second type semiconductor layer is a P type semiconductor layer. Correspondingly, the N-type semiconductor layer comprises an N-type ohmic contact layer, an N-type window layer and an N-type limiting layer which are sequentially stacked. The P-type semiconductor layer comprises a P-type limiting layer, a P-type window layer and a P-type ohmic contact layer which are stacked in sequence.
Referring to fig. 3, the preparation method of the LED epitaxial structure specifically includes the following steps:
step S1: providing a substrate 101;
step S2: sequentially growing a bottom buffer layer 102, a corrosion cut-off layer 103 and a first type semiconductor layer on the substrate 101, wherein the first type semiconductor layer sequentially comprises a first type window layer 202 and a first type limiting layer 203 from bottom to top, and the first type window layer 202 is a structural layer with gradually changed Al components;
step S3: an active layer 204 and a second type semiconductor layer are sequentially grown on the first type semiconductor layer.
The preparation process of the LED epitaxial structure is any one of a Metal Organic Chemical Vapor Deposition (MOCVD) process, a Molecular Beam Epitaxy (MBE) process or an ultra-high vacuum chemical vapor deposition (UHVCVD), and is preferably an MOCVD process. The following specific examples will be described by taking the MOCVD process as an example.
In step S1, the substrate 101 is preferably a GaAs (gallium arsenide) substrate, but may also be a Si (silicon) substrate, but is not limited thereto.
In step S2, a bottom buffer layer 102 is grown on the substrate 101. The bottom buffer layer 102 eliminates the influence of the surface defect of the substrate 101 on the LED epitaxial structure to the greatest extent, reduces the occurrence of defects and dislocation of the LED epitaxial structure, and provides a flat interface for the next growth. The material of the bottom buffer layer 102 is preferably GaAs, but is not limited thereto. The bottom buffer layer 102 is doped with a first type dopant, such as an N-type dopant, and may be at least one of silicon (Si) and tellurium (Te), but is not limited thereto. Further, the first type dopant is preferably Si.
The growth of the bottom buffer layer 102 is preferably to grow the bottom buffer layer 102 with a thickness of 100nm to 300nm in a reaction chamber of an MOCVD growth furnace. Preferably, the bottom buffer layer 102 is grown to a thickness of 150 nm.
After the bottom buffer layer 102 is grown, a corrosion-cut layer 103 is grown on the bottom buffer layer 102. The material of the corrosion-stopper layer 103 is preferably GaAs, but is not limited thereto. The first type dopant, for example, an N type dopant, may be at least one of silicon (Si) and tellurium (Te) doped in the corrosion cut layer 103, but is not limited thereto. Further, the first type dopant is preferably Si.
The growth of the corrosion cut-off layer 103 is preferably to grow the corrosion cut-off layer 103 with a thickness of 100nm to 300nm in a reaction chamber of an MOCVD growth furnace. Preferably, the corrosion-cut layer 103 is grown to a thickness of 150 nm.
After the etch stop layer 103 is grown, a first type semiconductor layer is grown on the etch stop layer 103. The first type semiconductor layer sequentially comprises a first type window layer 202 and a first type limiting layer 203 from bottom to top, and the first type window layer 202 is a structural layer with gradually changed Al components. The first type semiconductor layer may further include a first type ohmic contact layer 201, and the first type ohmic contact layer 201 is located between the corrosion cut-off layer 103 and the first type window layer 202.
Therefore, after the etch stop layer 103 is grown, the first type ohmic contact layer 201 is grown on the etch stop layer 103. The material of the first type ohmic contact layer 201 may be InGaAs or GaAs, preferably GaAs, but is not limited thereto. The N-type ohmic contact layer 201 is doped with a first type dopant, for example, an N-type dopant, which may be one of silicon (Si) and tellurium (Te), but is not limited thereto. Further, the first type dopant is preferably Si.
The first type ohmic contact layer 201 is preferably grown in a reaction chamber of an MOCVD growth furnace to form the first type ohmic contact layer 201 with a thickness of 20nm to 150 nm. Preferably, the first type ohmic contact layer 201 is grown to a thickness of 50 nm.
After the first type ohmic contact layer 201 is grown, the first type window layer 202 is grown on the first type ohmic contact layer 201. The primary functions of the first type window layer 202 are first type current spreading, light extraction and surface roughening. Because the layer is mainly used for current spreading and surface roughening, and the Al component is gradually changed to make it easier to roughen, multiple reflection of light inside the LED epitaxial structure can be reduced, and light is refracted from the inside, so that the Al component of the first window layer 202 is gradually changed to improve the light extraction efficiency.
Moreover, since the Al composition in the first type window layer 202 is graded, the refractive indexes corresponding to the materials with different Al compositions are different, and the material with a large Al composition has a large band gap and a small refractive index, the first type window layer 202 with graded Al composition has a graded refractive index structure, so that the internal reflection loss of the LED epitaxial structure can be reduced, the exit angle of the light emitted by the LED chip can be increased, the light can be coupled out to a great extent, and the light emitting efficiency of the LED chip can be improved.
The gradual Al composition change of the first type window layer 202 improves current spreading, so that current is easier to spread out, and does not gather under the electrode, and meanwhile, the gradual Al composition change can reduce the potential barrier of the electrode, so that the first type window layer 202 can reduce the operating voltage of the LED chip.
In addition, aging at high temperatures and high currents over a long period of time can result in excessive junction temperatures of the LED chip, and due to the slight lattice mismatch between the layers of the epitaxial structure, a large number of structural defects such as dislocations are formed at the interfaces between the layers. At higher temperatures, these defects propagate and propagate rapidly until they invade the light-emitting region (active layer) to form a large number of non-radiative recombination centers, severely degrading the injection efficiency and light-emitting efficiency of the light-emitting diode. The first window layer 202 adopts the gradual change mode of the Al component, so that the stress of the epitaxial structure under high-temperature aging can be effectively relieved, the derivation of defects is reduced, and the aging stability of the LED chip under high temperature is effectively improved.
The first type window layer 202 includes a single-layer structure or a multi-period structure composed of the first structure layer 2021, and the period number k ranges from 2 to 30. Referring to fig. 1, the first window layer 202 includes a single layer structureA first structural layer 2021, wherein the material of the first structural layer 2021 is Al x Ga 1-x As, and x is in the range of 0.05-0.30. In other embodiments, the first type window layer 202 may also include a multi-periodic structure formed by multiple first structure layers 2021, for example, a multi-periodic structure formed by 5 first structure layers 2021 when the number k of periods is equal to 5. The gradual change of the Al composition in the first type window layer 202 may include one or any combination of linear gradual change, nonlinear gradual change and stepwise change. Specifically, the linear gradation includes a linear gradation from a low Al composition to a high Al composition or a linear gradation from a low Al composition to a high Al composition from the first type window layer 202 toward the first type confinement layer 203; nonlinear gradation such as first gradation and then stabilization, or a manner of first gradation and then stabilization and then gradation, or parabolic gradation, etc.; the stepwise change is a stepwise abrupt change, for example, from 0.1 to 0.2, to 0.3, and so on. In a preferred embodiment, the Al composition x is linearly graded from 0.15 to 0.25 in a gradual progression from bottom to top (from the first type window layer 202 to the first type confinement layer 203).
The first type window layer 202 is doped with a first type dopant, for example, an N type dopant, and may be at least one of silicon (Si) and tellurium (Te), but is not limited thereto. Further, the first type dopant is preferably Si, and the doping concentration of Si is 0.7E18-5E 18cm -3 . The first type window layer 202 is preferably grown in a thickness of 1.5 μm to 8 μm in the reaction chamber of the MOCVD growth reactor. Preferably, a 7000nm thick window layer 202 of the first type is grown. If the thickness of the first window layer 202 is too thin, coarsening is not facilitated, and the brightness of the LED chip is low; if the thickness of the first type window layer 202 is too thick, the LED chip voltage is too high and the light absorption brightness is low (light efficiency is low), so that a good current spreading effect and roughening effect can be ensured by a proper thickness, and high photoelectric efficiency can be achieved.
After the first type window layer 202 is grown, the first type confinement layer 203 is grown on the first type window layer 202. The material of the first type confinement layer 203 is preferably AlGaAs, but not limited thereto. The first type dopant, for example, an N type dopant, may be at least one of silicon (Si) and tellurium (Te) doped in the first type confinement layer 203, but is not limited thereto. Further, the first type dopant is preferably Si.
The growth of the first type confinement layer 203 is preferably to grow the first type confinement layer 203 with a thickness of 200nm to 1000nm in a reaction chamber of an MOCVD growth reactor. Preferably, the first type confinement layer 203 is grown to a thickness of 500 nm.
In step S3, after the first type confinement layer 203 is grown, an active layer 204 is grown on the first type confinement layer 203. The active layer 204 is preferably a multiple quantum well structure, i.e., the active layer 204 is preferably a periodic structure composed of quantum wells and quantum barriers, and the number of periods of the active layer 204 is preferably 6-30 pairs. The material of the active layer 204 is preferably InGaAs/AlGaAs, but is not limited thereto. The thickness of the active layer 204 is 50nm to 2000nm, preferably 900nm.
The growth of the active layer 204 is preferably to grow the active layer 204 in a reaction chamber of a MOCVD growth furnace for 6 to 30 cycles. For example, 12 cycles of active layer 204 are grown.
After the active layer 204 is grown, a second type semiconductor layer is grown on the active layer 204. The second type semiconductor layer comprises the following components in sequence from bottom to top: a second type confinement layer 205, a second type window layer 206, and a second type ohmic contact layer 207.
Accordingly, after the active layer 204 is grown, a second type confinement layer 205 is grown on the active layer 204. The second type confinement layer 205 is for providing holes. The first type confinement layer 203 and the second type confinement layer 205 have two main roles as confinement layers, on one hand, minority carriers are limited not to overflow the active layer 204, and the composite luminous efficiency is improved; on the other hand, the active layer 204 is an important window, so that photons emitted by the active layer are easy to pass through the confinement layer, thereby improving the luminous efficiency of the LED chip.
The material of the second type confinement layer 205 is preferably AlGaAs, but not limited thereto. The second type dopant, for example, P-type dopant, may be at least one of magnesium (Mg) and zinc (Zn), but is not limited thereto, doped in the second type confinement layer 205. Further, the second type dopant is preferably Mg.
The growth of the second type confinement layer 205 is preferably to grow the second type confinement layer 205 with a thickness of 200nm to 1500nm in a reaction chamber of an MOCVD growth reactor. Preferably, the second type confinement layer 205 is grown to a thickness of 600 nm.
After the second type confinement layer 205 is grown, a second type window layer 206 is grown on the second type confinement layer 205. The material of the second type window layer 206 is preferably AlGaAs, but not limited thereto. The second type window layer 206 is doped with a second type dopant, for example, a P type dopant, and may be at least one of magnesium (Mg) and zinc (Zn), but is not limited thereto. Further, the second type dopant is preferably Mg.
The growth of the second type window layer 206 is preferably to grow the second type window layer 206 with a thickness of 200nm to 3000nm in a reaction chamber of an MOCVD growth furnace. Preferably, the window layer 206 of the second type is grown to a thickness of 1200 nm.
After the second type window layer 206 is grown, the second type ohmic contact layer 207 is grown on the second type window layer 206. The second type ohmic contact layer 207 is for forming an ohmic contact with the metal electrode. The material of the second type ohmic contact layer 207 is preferably GaP, but is not limited thereto. The second type ohmic contact layer 207 may be doped with carbon (C).
The second type ohmic contact layer 207 is preferably grown in a reaction chamber of an MOCVD growth furnace to a thickness of 20nm to 100 nm. Preferably, the second type ohmic contact layer 207 is grown to a thickness of 50 nm.
Example two
Fig. 2 is a schematic structural diagram of a first type window layer according to this embodiment. The difference between the present embodiment and the first embodiment is only that the first type window layer 202 has a different structure, and the portions having the same structure are not described herein.
Specifically, the first window layer 202 in the LED epitaxial structure includes a two-layer structure composed of a first structure layer 2021 and a second structure layer 2022 or a plurality of weeks composed of alternately stacked first structure layer 2021 and second structure layer 2022The period number k is in the range of 2 to 30, preferably 20 to 30. As shown in fig. 2, the first type window layer 202 includes a two-layer structure formed by a first structural layer 2021 and a second structural layer 2022. The first structural layer 2021 is made of Al a Ga 1-a As, the material of the second structure layer 2022 is Al m Ga 1-m As, i.e. the material of the first window layer 202 is Al a Ga 1-a As/Al m Ga 1-m As. Wherein m is more than or equal to 0.05 and less than or equal to 0.30; a is more than or equal to 0.05 and less than or equal to 0.30. In other embodiments, the first type window layer 202 may also include a multicycle structure composed of multiple first structure layers 2021 and second structure layers 2022, for example, when the cycle number k is equal to 10, the first structure layers 2021 and the second structure layers 2022 are alternately stacked to form a multicycle structure, i.e. the material of the first type window layer 202 is (Al a Ga 1-a As/Al m Ga 1-m As) 10 . And, in the same period, the difference between the maximum value and the minimum value of the Al component a and the Al component m is greater than 0.15, so as to ensure that the first type window layer 202 has a better corrosion limiting effect on the roughening solution.
After the first type ohmic contact layer 201 is grown, the first structural layer 2021 is grown on the first type ohmic contact layer 201, and then the second structural layer 2022 is grown, so that the growth of the first type window layer 202 is completed for one period; continuing to alternately grow the first structure layer 2021 and the second structure layer 2022 completes the growth of the first type window layer 202 of the multicycle structure. The gradual change of the Al composition in the first type window layer 202 may include one or any combination of linear gradual change, nonlinear gradual change and stepwise change. Specifically, the linear gradation includes a linear gradation from a low Al composition to a high Al composition or a linear gradation from a low Al composition to a high Al composition from the first type window layer 202 toward the first type confinement layer 203; nonlinear gradation such as first gradation and then stabilization, or a manner of first gradation and then stabilization and then gradation, or parabolic gradation, etc.; the stepwise change is a stepwise abrupt change, for example, from 0.1 to 0.2, to 0.3, and so on. In a preferred embodiment, the Al composition a in the first structural layer 2021 is linearly graded progressively increasing from 0.15 to 0.25 from bottom to top (from the first type window layer 202 to the first type confinement layer 203), and the Al composition m in the second structural layer 2022 is linearly graded progressively decreasing from 0.25 to 0.15 from bottom to top (from the first type window layer 202 to the first type confinement layer 203).
The total thickness of the first type window layer 202 is 1.5 μm to 8 μm. Preferably, the thickness of the first type window layer 202 is 7000nm. If the thickness of the first window layer 202 is too thin, coarsening is not facilitated, and the brightness of the LED chip is low; if the thickness of the first type window layer 202 is too thick, the LED chip voltage is too high and the light absorption brightness is low (light efficiency is low), so that a good current spreading effect and roughening effect can be ensured by a proper thickness, and high photoelectric efficiency can be achieved.
According to the invention, the first window layer with gradually changed Al components is adopted, and the layer structure is formed into a graded refractive index structure by changing the Al components, so that the internal reflection loss of the LED epitaxial structure can be reduced, the emergent angle of emergent light of the LED epitaxial structure is increased, more light can be coupled out, the emergent light efficiency of the LED chip is improved, and the luminous efficiency of the LED chip is further improved; meanwhile, due to gradual change of the Al component, the working voltage of the LED chip can be effectively reduced, and the performance of the LED chip is improved.
Furthermore, the first type window layer with gradually changed Al components is adopted, so that the stress of the epitaxial structure under high-temperature aging can be effectively relieved, the derivative of defects is reduced, and the aging stability of the LED chip under high temperature is effectively improved.
In addition, it will be understood that while the invention has been described in terms of preferred embodiments, the above embodiments are not intended to limit the invention. Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art without departing from the scope of the technology, or the technology can be modified to be equivalent. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
It is also to be understood that this invention is not limited to the particular methodology, compounds, materials, manufacturing techniques, uses, and applications described herein, as such may vary. It should also be understood that the terminology described herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. It must be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a step" means a reference to one or more steps, and may include sub-steps. All conjunctions used should be understood in the broadest sense. Thus, the word "or" should be understood as having the definition of a logical "or" rather than a logical exclusive or "unless the context clearly indicates the contrary. Structures described herein will be understood to also refer to the functional equivalents of such structures. Language that may be construed as approximate should be construed unless the context clearly indicates the contrary.
Claims (19)
1. The LED epitaxial structure is characterized by comprising the following components in sequence from bottom to top: the semiconductor device comprises a bottom buffer layer, a corrosion stop layer, a first type semiconductor layer, an active layer and a second type semiconductor layer which are positioned on a substrate, wherein the first type semiconductor layer sequentially comprises a first type window layer and a first type limiting layer from bottom to top, the first type window layer is made of AlGaAs, the first type window layer comprises a single-layer structure or a multicycle structure formed by first structure layers, the range of the cycle number k is 2-30, and the first structure layer is made of Al x Ga 1-x As, wherein x is more than or equal to 0.05 and less than or equal to 0.30; or the first window layer comprises a two-layer structure formed by a first structure layer and a second structure layer or a multicycle structure formed by alternately stacking the first structure layer and the second structure layer, the cycle number k ranges from 2 to 30, and the first structure layer is Al a Ga 1-a As, the second structural layer is Al m Ga 1-m As, and m is more than or equal to 0.05 and less than or equal to 0.30,0.05 a is less than or equal to 0.30, the first type window layer is a structural layer with gradually changed Al components, and the thickness of the first type window layer is 1.5-8 mu m.
2. The LED epitaxial structure of claim 1, wherein the gradual change of Al composition in the first type window layer comprises one or any combination of a linear change, a non-linear change, a stepwise change.
3. The LED epitaxial structure of claim 2, wherein the gradual change of Al composition in the linear change is a linear change from large to small or a linear change from small to large in a direction from the first type window layer toward the first type confinement layer.
4. The LED epitaxial structure of claim 1, wherein the difference between the maximum and minimum of Al composition a and Al composition m in the first and second structural layers is greater than 0.15 during the same period.
5. The LED epitaxial structure of claim 1, wherein Si is doped in the first window layer with a doping concentration of 0.7E18-5E 18cm -3 。
6. The LED epitaxial structure of claim 1, wherein the first type semiconductor layer further comprises a first type ohmic contact layer, and the first type ohmic contact layer is located between the etch stop layer and the first type window layer.
7. The LED epitaxial structure of claim 1, wherein the second type semiconductor layer comprises, in order from bottom to top: a second type limiting layer, a second type window layer and a second type ohmic contact layer.
8. The LED epitaxial structure of claim 1, wherein the first type semiconductor layer is an N-type semiconductor layer and the second type semiconductor layer is a P-type semiconductor layer.
9. The LED epitaxial structure of claim 1, wherein the substrate comprises a GaAs substrate or a Si substrate.
10. The preparation method of the LED epitaxial structure is characterized by comprising the following steps of:
providing a substrate;
sequentially growing a bottom buffer layer, a corrosion cut-off layer and a first type semiconductor layer on the substrate, wherein the first type semiconductor layer sequentially comprises a first type window layer and a first type limiting layer from bottom to top, the first type window layer is made of AlGaAs, the first type window layer comprises a single-layer structure or a multicycle structure formed by a first structure layer, the range of the cycle number k is 2 to 30, and the first structure layer is Al x Ga 1-x As, wherein x is more than or equal to 0.05 and less than or equal to 0.30; or the first window layer comprises a two-layer structure formed by a first structure layer and a second structure layer or a multicycle structure formed by alternately stacking the first structure layer and the second structure layer, the cycle number k ranges from 2 to 30, and the first structure layer is Al a Ga 1-a As, the second structural layer is Al m Ga 1-m As, m is more than or equal to 0.05 and less than or equal to 0.30,0.05, a is more than or equal to 0.30, the first type window layer is a structural layer with gradually changed Al components, and the thickness of the first type window layer is 1.5-8 mu m;
and sequentially growing an active layer and a second type semiconductor layer on the first type semiconductor layer.
11. The method of claim 10, wherein the gradual change of the Al composition in the first window layer comprises one or any combination of a linear gradual change, a nonlinear gradual change, and a stepwise change.
12. The method of manufacturing an LED epitaxial structure of claim 11, wherein the gradual change of the Al composition in the linear gradual change is a linear gradual change from large to small or a linear gradual change from small to large from the first type window layer to the first type confinement layer.
13. The method of claim 10, wherein the difference between the maximum and minimum values of the Al component a and the Al component m in the first and second structural layers is greater than 0.15 in the same period.
14. The method of claim 10, wherein the first window layer is doped with Si, and the doping concentration of Si is 0.7E18-5E 18cm -3 。
15. The method of manufacturing an LED epitaxial structure of claim 10, wherein said first type semiconductor layer further comprises a first type ohmic contact layer, and wherein said first type ohmic contact layer is located between said etch stop layer and said first type window layer.
16. The method for manufacturing an LED epitaxial structure of claim 10, wherein the second semiconductor layer comprises, in order from bottom to top: a second type limiting layer, a second type window layer and a second type ohmic contact layer.
17. The method of claim 10, wherein the first semiconductor layer is an N-type semiconductor layer and the second semiconductor layer is a P-type semiconductor layer.
18. The method of claim 10, wherein the substrate comprises a GaAs substrate or a Si substrate.
19. The method of claim 10, wherein the process for preparing the epitaxial structure is any one of MOCVD, molecular beam epitaxy, HVPE, plasma assisted chemical vapor deposition, and sputtering.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1320279A (en) * | 1999-08-23 | 2001-10-31 | 日本板硝子株式会社 | Light-emitting thyristor and self-scanning light-emitting device |
| CN103500784A (en) * | 2013-09-26 | 2014-01-08 | 厦门乾照光电股份有限公司 | Epitaxial structure, growth process and chip process of near-infrared light emitting diode |
| CN104167478A (en) * | 2014-08-11 | 2014-11-26 | 厦门乾照光电股份有限公司 | Coarsening method for infrared light emitting diode with multiple coarsening layers |
| CN104332537A (en) * | 2014-10-17 | 2015-02-04 | 厦门乾照光电股份有限公司 | High concentration Te doped light emitting diode epitaxial structure |
| CN111106214A (en) * | 2019-12-31 | 2020-05-05 | 厦门士兰明镓化合物半导体有限公司 | Light emitting diode chip and preparation method thereof |
| CN111819703A (en) * | 2019-11-28 | 2020-10-23 | 天津三安光电有限公司 | Light-emitting element |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060023763A1 (en) * | 2004-07-28 | 2006-02-02 | Nlight Photonics Corporation | Semiconductor lasers with hybrid materials systems |
-
2021
- 2021-11-03 CN CN202111294804.3A patent/CN114023857B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1320279A (en) * | 1999-08-23 | 2001-10-31 | 日本板硝子株式会社 | Light-emitting thyristor and self-scanning light-emitting device |
| CN103500784A (en) * | 2013-09-26 | 2014-01-08 | 厦门乾照光电股份有限公司 | Epitaxial structure, growth process and chip process of near-infrared light emitting diode |
| CN104167478A (en) * | 2014-08-11 | 2014-11-26 | 厦门乾照光电股份有限公司 | Coarsening method for infrared light emitting diode with multiple coarsening layers |
| CN104332537A (en) * | 2014-10-17 | 2015-02-04 | 厦门乾照光电股份有限公司 | High concentration Te doped light emitting diode epitaxial structure |
| CN111819703A (en) * | 2019-11-28 | 2020-10-23 | 天津三安光电有限公司 | Light-emitting element |
| CN111106214A (en) * | 2019-12-31 | 2020-05-05 | 厦门士兰明镓化合物半导体有限公司 | Light emitting diode chip and preparation method thereof |
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