An epitaxial structure of a light emitting diode and a method for preparing the same

Abstract

Disclosed are an epitaxial structure of a light-emitting diode and a preparation method thereof. The epitaxial structure of the light-emitting diode comprises: a substrate; and a first semiconductor layer, a first barrier layer, a second barrier layer, a multi-quantum well layer and a second semiconductor layer stacked in sequence on the substrate, wherein the doping types of the first barrier layer and the second semiconductor layer are opposite to each other, wherein the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well layer and the second semiconductor layer are carbon-doped respectively, and the carbon doping concentration of the multi-quantum well layer is ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer. The epitaxial structure of the light-emitting diode and the preparation method thereof of the present invention reduce the rate of electron injection into the multi-quantum well and reduce the probability of electron overflow from the multi-quantum well by setting the change of the carbon doping concentration of each layer in the epitaxial structure, thereby improving the luminous efficiency of the light-emitting diode.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an epitaxial structure of a light emitting diode and a preparation method thereof. Background Art

[0002] Light-emitting diodes (LEDs) are energy-saving and environmentally friendly, have high luminous efficiency, low cost, long life, a wide wavelength range (e.g. 200nm~1100nm), and small size. Therefore, in the field of traditional lighting, light-emitting diodes have completely replaced incandescent lamps and fluorescent lamps and become the light source for ordinary household lighting. In addition, light-emitting diodes can also be used in Mini-LED, indoor high-resolution display screens, outdoor display screens, mobile phone backlights, TV backlights, laptop backlights, household lamps, street lamps, car lights, flashlights, and other fields.

[0003] Light-emitting diodes usually use nitride semiconductor epitaxial layers. Traditional nitride semiconductor epitaxial layers usually use heterogeneous substrates. The lattice mismatch and thermal mismatch between the heterogeneous substrate and the nitride epitaxial layer are large, resulting in a higher defect density and polarization effect, causing non-radiative recombination and spatial separation of electron wave functions, which reduces the luminous efficiency of the light-emitting diode. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide an epitaxial structure of a light-emitting diode and a method for preparing the same. By setting the carbon doping concentration and silicon doping concentration of each layer in the epitaxial structure, the rate of electron injection into the multi-quantum well layer is reduced, and the probability of electron overflow from the multi-quantum well layer is reduced, thereby improving the luminous efficiency of the light-emitting diode.

[0005] A first aspect of the present invention provides an epitaxial structure of a light emitting diode, comprising:

[0006] substrate; and

[0007] A first semiconductor layer, a first barrier layer, a second barrier layer, a multi-quantum well layer and a second semiconductor layer are sequentially stacked on the substrate, wherein the doping types of the first barrier layer and the second semiconductor layer are opposite to each other,

[0008] Among them, the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well and the second semiconductor layer are respectively carbon-doped, and the carbon doping concentration of the multi-quantum well layer is ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer.

[0009] Preferably, the first semiconductor layer, the first barrier layer, the second barrier layer, and the multi-quantum well layer are respectively doped with silicon, and the silicon doping concentrations are the same or different, and the second semiconductor layer is doped with magnesium.

[0010] Preferably, the silicon doping concentration of the multi-quantum well layer is ≤ the silicon doping concentration of the first barrier layer ≤ the silicon doping concentration of the second barrier layer ≤ the silicon doping concentration of the first semiconductor layer.

[0011] Preferably, the carbon doping concentration of the first semiconductor layer is 4E16cm -3 To 1E17cm -3 ; The silicon doping concentration of the first semiconductor layer is 1E19cm -3 To 1E20cm -3 .

[0012] Preferably, the carbon doping concentration of the first barrier layer is 4E16cm -3 To 1E17cm -3 ; The silicon doping concentration of the first barrier layer is 5E17cm -3 To 1E19cm -3 .

[0013] Preferably, the carbon doping concentration of the second barrier layer is 3E17cm -3 To 5E18cm -3 The silicon doping concentration of the second barrier layer is 5E17cm -3 To 1E19cm -3 .

[0014] Preferably, the carbon doping concentration of the multi-quantum well layer is 1E16cm -3 To 1E18cm -3 The silicon doping concentration of the multi-quantum well layer is 1E17cm -3 To 1E18cm -3 .

[0015] Preferably, the carbon doping concentration of the second semiconductor layer is 1E17cm -3 To 5E19cm -3 The magnesium doping concentration of the second semiconductor layer is 1E18cm -3 To 5E21cm -3 .

[0016] Preferably, it further comprises an unintentional doping layer, wherein the unintentional doping layer is located between the substrate and the first semiconductor layer.

[0017] Preferably, the unintentional doping layer is carbon-doped, and the carbon doping concentration of the unintentional doping layer is ≤ the carbon doping concentration of the multi-quantum well layer ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer.

[0018] Preferably, the unintentionally doped layer is silicon-doped, and the silicon doping concentration of the unintentionally doped layer is ≤ the silicon doping concentration of the multi-quantum well layer ≤ the silicon doping concentration of the first barrier layer ≤ the silicon doping concentration of the second barrier layer ≤ the silicon doping concentration of the first semiconductor layer.

[0019] Preferably, the carbon doping concentration of the unintentionally doped layer is 1E16 cm -3 To 4E16cm -3 The silicon doping concentration of the unintentionally doped layer is 1E17cm -3 To 1E20cm -3 .

[0020] Preferably, the unintentionally doped layer, the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well layer and the second semiconductor layer are at least one of GaN, AlN, InN, AlGaN, AlInN, InGaN, AlInGaN, GaN / InN superlattice, GaN / AlN superlattice, InN / GaN superlattice, GaN / AlGaN superlattice, GaN / AlInN superlattice, GaN / InGaN superlattice, GaN / AlInGaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInN superlattice, InGaN / AlInGaN superlattice, AlGaN / AlInN superlattice, AlGaN / AlInGaN superlattice, AlInGaN / AlInGaN superlattice, InGaN / GaN shallow quantum well, InGaN / AlGaN shallow quantum well and InGaN / AlInGaN shallow quantum well.

[0021] A second aspect of the present invention provides a method for manufacturing an epitaxial structure of a light-emitting diode, comprising: forming a first semiconductor layer, a first barrier layer, a second barrier layer, a multi-quantum well layer and a second semiconductor layer stacked in sequence on a substrate, wherein the doping types of the first barrier layer and the second semiconductor layer are opposite to each other;

[0022] Among them, the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well and the second semiconductor layer are respectively carbon-doped, and the carbon doping concentration of the multi-quantum well layer is ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer.

[0023] Preferably, the first semiconductor layer, the first barrier layer, the second barrier layer, and the multi-quantum well layer are respectively doped with silicon, and the silicon doping concentrations are the same or different, and the second semiconductor layer is doped with magnesium.

[0024] Preferably, the silicon doping concentration of the multi-quantum well layer is ≤ the silicon doping concentration of the first barrier layer ≤ the silicon doping concentration of the second barrier layer ≤ the silicon doping concentration of the first semiconductor layer.

[0025] Preferably, the carbon doping concentration of the first semiconductor layer is 4E16cm -3 To 1E17cm -3 ; The silicon doping concentration of the first semiconductor layer is 1E19cm -3 To 1E20cm -3 .

[0026] Preferably, the carbon doping concentration of the first barrier layer is 4E16cm -3 To 1E17cm -3 ; The silicon doping concentration of the first barrier layer is 5E17cm -3 To 1E19cm -3 .

[0027] Preferably, the carbon doping concentration of the second barrier layer is 3E17cm -3 To 5E18cm -3 The silicon doping concentration of the second barrier layer is 5E17cm -3 To 1E19cm -3 .

[0028] Preferably, the carbon doping concentration of the multi-quantum well layer is 1E16cm -3 To 1E18cm -3 The silicon doping concentration of the multi-quantum well layer is 1E17cm -3 To 1E18cm -3 .

[0029] Preferably, the carbon doping concentration of the second semiconductor layer is 1E17cm -3 To 5E19cm -3 The magnesium doping concentration of the second semiconductor layer is 1E18cm -3 To 5E21cm -3 .

[0030] Preferably, it further comprises an unintentional doping layer, wherein the unintentional doping layer is located between the substrate and the first semiconductor layer.

[0031] Preferably, the unintentional doping layer is carbon-doped, and the carbon doping concentration of the unintentional doping layer is ≤ the carbon doping concentration of the multi-quantum well layer ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer.

[0032] Preferably, the unintentionally doped layer is silicon-doped, and the silicon doping concentration of the unintentionally doped layer is ≤ the silicon doping concentration of the multi-quantum well layer ≤ the silicon doping concentration of the first barrier layer ≤ the silicon doping concentration of the second barrier layer ≤ the silicon doping concentration of the first semiconductor layer.

[0033] Preferably, the carbon doping concentration of the unintentionally doped layer is 1E16 cm -3 To 4E16cm -3 The silicon doping concentration of the unintentionally doped layer is 1E17cm -3 To 1E20cm -3 .

[0034] Preferably, the unintentionally doped layer, the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well layer and the second semiconductor layer are at least one of GaN, AlN, InN, AlGaN, AlInN, InGaN, AlInGaN, GaN / InN superlattice, GaN / AlN superlattice, InN / GaN superlattice, GaN / AlGaN superlattice, GaN / AlInN superlattice, GaN / InGaN superlattice, GaN / AlInGaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInN superlattice, InGaN / AlInGaN superlattice, AlGaN / AlInN superlattice, AlGaN / AlInGaN superlattice, AlInGaN / AlInGaN superlattice, InGaN / GaN shallow quantum well, InGaN / AlGaN shallow quantum well and InGaN / AlInGaN shallow quantum well.

[0035] The epitaxial structure of a light-emitting diode and the preparation method thereof provided in the embodiment of the present invention dopes carbon elements in each layer of the epitaxial structure, thereby improving the antistatic ability of the light-emitting diode and improving the luminous efficiency of the light-emitting diode.

[0036] Furthermore, the present invention reduces the rate of electron injection into the multi-quantum well layer and reduces the probability of electron overflow from the multi-quantum well layer by setting the change of carbon doping concentration and silicon doping concentration of each layer in the epitaxial structure. At the same time, the rate of hole injection into the multi-quantum well layer is increased, thereby reducing the difference in electron-hole concentration in the multi-quantum well layer, improving the consistency of electron and hole concentration in the multi-quantum well layer, preventing non-radiative recombination, and improving the overlap probability of electron-hole wave functions and the electron-hole recombination efficiency, thereby improving the luminous efficiency of the light-emitting diode.

[0037] Furthermore, the carbon doping concentration and the silicon doping concentration of each semiconductor structure layer in the epitaxial structure vary gradually to obtain better expansion of electrons and holes, which is beneficial to the uniform distribution of electrons and holes in the multi-quantum well layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0039] Figure 1 A cross-sectional view showing an epitaxial structure of a light emitting diode according to a first embodiment of the present invention;

[0040] Figure 2 A cross-sectional view showing an epitaxial structure of a light emitting diode according to a second embodiment of the present invention;

[0041] Figure 3 A cross-sectional view of a light emitting diode according to a third embodiment of the present invention is shown;

[0042] Figure 4a and Figure 4b The SIMS test results of carbon doping concentration and silicon doping concentration in the epitaxial structure of the light emitting diode in the third embodiment of the present invention are shown;

[0043] Figure 5a and Figure 5b The comparison results of the package brightness and light efficiency of the light emitting diode of the third embodiment of the present invention and the light emitting diode in the prior art are shown;

[0044] Figure 6a to Figure 6b The cross-sectional views at various stages in the manufacturing process of the light emitting diode according to the third embodiment of the present invention are shown. DETAILED DESCRIPTION

[0045] The present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same device is represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale. In addition, some well-known parts may not be shown.

[0046] The present invention may be embodied in various forms, some examples of which will be described below.

[0047] In the prior art, due to the lattice mismatch and thermal mismatch between the substrate and the epitaxial layer, the epitaxial layer produces a high defect density and polarization reaction, which in turn produces non-radiative recombination and spatial separation of electron wave functions, further reducing the luminous efficiency of the light-emitting diode. Specifically, since the hole ionization efficiency of the epitaxial layer is much lower than the electron ionization efficiency, the hole concentration is more than 1 to 2 orders of magnitude lower than the electron concentration, and the excess electrons cannot participate in radiative recombination and overflow from the multi-quantum well to the p-type semiconductor to produce non-radiative recombination; at the same time, the low hole ionization efficiency will lead to a low hole concentration in the p-type semiconductor and it is difficult to effectively inject it into the multi-quantum well, resulting in low efficiency of hole injection into the multi-quantum well; therefore, the electron-hole concentration of the multi-quantum well is greatly different, the probability of electron-hole wave function overlap is low, and the electron-hole recombination efficiency is low, resulting in low luminous efficiency of the multi-quantum well.

[0048] A first aspect of the present invention provides an epitaxial structure of a light emitting diode. Figure 1 FIG. 4 is a cross-sectional view showing the epitaxial structure of a light emitting diode according to a first embodiment of the present invention. Figure 1 As shown, the epitaxial structure of the light emitting diode includes: a substrate 110 and a first semiconductor layer 122 , a first barrier layer 123 , a second barrier layer 124 , a multi-quantum well layer 125 and a second semiconductor layer 126 stacked in sequence on the substrate 110 .

[0049] The substrate 110 includes but is not limited to a mirror surface or a micron-scale / nanoscale patterned sapphire substrate. In a preferred embodiment, the substrate 110 is, for example, a micron-scale patterned sapphire. In other alternative embodiments, the substrate 110 may also be gallium oxide, zinc oxide, lithium gallate, lithium aluminate, etc.

[0050] The materials of the first semiconductor layer 122 , the first barrier layer 123 , the second barrier layer 124 , the multi-quantum well layer 125 and the second semiconductor layer 126 are any one or any combination of nitride, ternary mixed crystal nitride, quaternary mixed crystal nitride, superlattice structure and shallow quantum well structure. Specifically, for example, it can be any one or any combination of GaN, AlN, InN, AlGaN, AlInN, InGaN, AlInGaN, GaN / InN superlattice, GaN / AlN superlattice, InN / GaN superlattice, GaN / AlGaN superlattice, GaN / AlInN superlattice, GaN / InGaN superlattice, GaN / AlInGaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInN superlattice, InGaN / AlInGaN superlattice, AlGaN / AlInN superlattice, AlGaN / AlInGaN superlattice, AlInGaN / AlInGaN superlattice, InGaN / GaN shallow quantum well, InGaN / AlGaN shallow quantum well, InGaN / AlInGaN shallow quantum well.

[0051] In a specific embodiment, the first semiconductor layer 122 is, for example, a gallium nitride material layer of a first doping type (for example, N-type), and the second semiconductor layer 126 is, for example, a gallium nitride material layer of a second doping type (for example, P-type). The multi-quantum well layer 125 is, for example, a multi-quantum well (MQW, multiple quantum well) structure layer. The MQW multi-quantum well structure includes, for example, GaN / InN / AlN, but is not limited thereto.

[0052] The first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, the multi-quantum well layer 125, and the second semiconductor layer 126 are carbon-doped, respectively, and the carbon doping concentrations of the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, the multi-quantum well layer 125, and the second semiconductor layer 126 are the same or different. Specifically, the carbon doping concentration of the multi-quantum well layer 125 is ≤ the carbon doping concentration of the first barrier layer 123 ≤ the carbon doping concentration of the first semiconductor layer 122 ≤ the carbon doping concentration of the second barrier layer 124 ≤ the carbon doping concentration of the second semiconductor layer 126.

[0053] The carbon doping concentration in the multi-quantum well layer 125, the first barrier layer 123, the first semiconductor layer 122, the second barrier layer 124, and the second semiconductor layer 126 increases according to a gradual gradient, or increases according to a transition gradient; wherein in the gradual gradient increase, the carbon doping concentration is a value that changes continuously in sequence; in the transition gradient change, the change value of the carbon doping concentration is a fixed value. In this embodiment, the carbon doping concentration in the multi-quantum well layer 125, the first barrier layer 123, the first semiconductor layer 122, the second barrier layer 124, and the second semiconductor layer 126 increases according to a gradual gradient, for example.

[0054] Further, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, and the multi-quantum well layer 125 are respectively doped with silicon, and the second semiconductor layer 126 is doped with magnesium. Specifically, the silicon doping concentrations of the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, and the multi-quantum well layer 125 are the same or different. In this embodiment, the silicon doping concentration of the multi-quantum well layer 125 is ≤ the silicon doping concentration of the first barrier layer 123 ≤ the silicon doping concentration of the second barrier layer 124 ≤ the silicon doping concentration of the first semiconductor layer 122.

[0055] The silicon doping concentration of the multi-quantum well layer 125, the first barrier layer 123, the second barrier layer 124, and the first semiconductor layer 122 increases in a gradual gradient, or in a transitional gradient; wherein in the gradual gradient increase, the carbon doping concentration is a value that changes continuously in sequence; in the transitional gradient change, the change value of the carbon doping concentration is a fixed value. In this embodiment, the silicon doping concentration in the multi-quantum well layer 125, the first barrier layer 123, the second barrier layer 124, and the first semiconductor layer 122 increases in a transitional gradient, for example.

[0056] In a specific embodiment, the carbon doping concentration of the first semiconductor layer 122 is 4E16 cm -3 To 1E17cm -3 , the silicon doping concentration is 1E19cm -3 To 1E20cm -3 ; The carbon doping concentration of the first barrier layer 123 is 4E16cm -3 To 1E17cm -3 , the silicon doping concentration is 5E17cm -3 To 1E19cm -3 ; The carbon doping concentration of the second barrier layer 124 is 3E17cm -3 To 5E18cm -3 , the silicon doping concentration is 5E17cm -3 To 1E19cm -3The carbon doping concentration of the multi-quantum well layer 125 is 1E16cm -3 To 1E18cm -3 , the silicon doping concentration is 1E17cm -3 To 1E18cm -3 The carbon doping concentration of the second semiconductor layer 126 is 1E17cm -3 To 5E19cm -3 , the magnesium doping concentration is 1E18cm -3 To 5E21cm -3 .

[0057] The second aspect of the present invention provides a method for manufacturing the epitaxial structure of the light emitting diode of the first embodiment, wherein the method comprises forming a first semiconductor layer 122 , a first barrier layer 123 , a second barrier layer 124 , a multi-quantum well layer 125 and a second semiconductor layer 126 stacked in sequence on a substrate 110 .

[0058] The substrate 110 includes but is not limited to a mirror surface or a micron-scale / nanoscale patterned sapphire substrate. In a preferred embodiment, the substrate 110 is, for example, a micron-scale patterned sapphire. In other alternative embodiments, the substrate 110 may also be gallium oxide, zinc oxide, lithium gallate, lithium aluminate, etc.

[0059] The first semiconductor layer 122 is, for example, a gallium nitride material layer of a first doping type (for example, N-type), and the second semiconductor layer 126 is, for example, a gallium nitride material layer of a second doping type (for example, P-type). The multi-quantum well layer 125 is, for example, a multi-quantum well (MQW, multiple quantum well) structure layer. The MQW multi-quantum well structure includes, for example, GaN / InN / AlN, but is not limited thereto.

[0060] The first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, the multi-quantum well layer 125, and the second semiconductor layer 126 are carbon-doped, respectively, and the carbon doping concentrations of the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, the multi-quantum well layer 125, and the second semiconductor layer 126 are the same or different. Specifically, the carbon doping concentration of the multi-quantum well layer 125 is ≤ the carbon doping concentration of the first barrier layer 123 ≤ the carbon doping concentration of the first semiconductor layer 122 ≤ the carbon doping concentration of the second barrier layer 124 ≤ the carbon doping concentration of the second semiconductor layer 126. The carbon doping concentrations in the multi-quantum well layer 125, the first barrier layer 123, the first semiconductor layer 122, the second barrier layer 124, and the second semiconductor layer 126 increase in a gradual gradient.

[0061] Further, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, and the multi-quantum well layer 125 are respectively doped with silicon, and the second semiconductor layer 126 is doped with magnesium. Specifically, the silicon doping concentrations of the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, and the multi-quantum well layer 125 are the same or different. In this embodiment, the silicon doping concentration of the multi-quantum well layer 125 is ≤ the silicon doping concentration of the first barrier layer 123 ≤ the silicon doping concentration of the second barrier layer 124 ≤ the silicon doping concentration of the first semiconductor layer 122.

[0062] In a specific embodiment, the carbon doping concentration of the first semiconductor layer 122 is 4E16 cm -3 To 1E17cm -3 , the silicon doping concentration is 1E19cm -3 To 1E20cm -3 ; The carbon doping concentration of the first barrier layer 123 is 4E16cm -3 To 1E17cm -3 , the silicon doping concentration is 5E17cm -3 To 1E19cm -3 ; The carbon doping concentration of the second barrier layer 124 is 3E17cm -3 To 5E18cm -3 , the silicon doping concentration is 5E17cm -3 To 1E19cm -3 The carbon doping concentration of the multi-quantum well layer 125 is 1E16cm -3 To 1E18cm -3 , the silicon doping concentration is 1E17cm -3 To 1E18cm -3 The carbon doping concentration of the second semiconductor layer 126 is 1E17cm -3 To 5E19cm -3 , the magnesium doping concentration is 1E18cm -3 To 5E21cm -3 .

[0063] The third aspect of the present invention provides an epitaxial structure of a light emitting diode according to the second embodiment of the present invention. Figure 2 The cross-sectional view of the epitaxial structure of the light emitting diode of the second embodiment of the present invention is shown. Different from the first embodiment, in this embodiment, the epitaxial structure further includes an unintentional doping layer 121 , and the unintentional doping layer 121 is located between the substrate 110 and the first semiconductor layer 122 .

[0064] In this embodiment, the unintentionally doped layer 121 is, for example, a gallium nitride (GaN) material layer.

[0065] The unintentional doping layer 121, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, the multi-quantum well layer 125 and the second semiconductor layer 126 are carbon-doped respectively, and the carbon doping concentrations are the same or different. Specifically, the carbon doping concentration of the unintentional doping layer 121 is ≤ the carbon doping concentration of the multi-quantum well layer 125 ≤ the carbon doping concentration of the first barrier layer 123 ≤ the carbon doping concentration of the first semiconductor layer 122 ≤ the carbon doping concentration of the second barrier layer 124 ≤ the carbon doping concentration of the second semiconductor layer 126. The carbon doping concentrations in the unintentional doping layer 121, the multi-quantum well layer 125, the first barrier layer 123, the first semiconductor layer 122, the second barrier layer 124 and the second semiconductor layer 126 increase in a gradual gradient.

[0066] Further, the unintentional doped layer 121, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, and the multi-quantum well layer 125 are respectively doped with silicon, and the second semiconductor layer 126 is doped with magnesium. The silicon doping concentrations of the unintentional doped layer 121, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, and the multi-quantum well layer 125 are the same or different. Specifically, the silicon doping concentration of the unintentional doped layer 121 is ≤ the silicon doping concentration of the multi-quantum well layer 125 ≤ the silicon doping concentration of the first barrier layer 123 ≤ the silicon doping concentration of the second barrier layer 124 ≤ the silicon doping concentration of the first semiconductor layer 122.

[0067] In a specific embodiment, the carbon doping concentration of the unintentionally doped layer 121 is 1E16 cm -3 To 4E16cm -3 , the silicon doping concentration is 1E17cm -3 To 1E20cm -3 ; The carbon doping concentration of the first semiconductor layer 122 is 4E16cm -3 To 1E17cm -3 , the silicon doping concentration is 1E19cm -3 To 1E20cm -3 ; The carbon doping concentration of the first barrier layer 123 is 4E16cm -3 To 1E17cm -3 , the silicon doping concentration is 5E17cm -3 To 1E19cm -3 ; The carbon doping concentration of the second barrier layer 124 is 3E17cm -3 To 5E18cm -3 , the silicon doping concentration is 5E17cm -3 To 1E19cm -3The carbon doping concentration of the multi-quantum well layer 125 is 1E16cm -3 To 1E18cm -3 , the silicon doping concentration is 1E17cm -3 To 1E18cm -3 The carbon doping concentration of the second semiconductor layer 126 is 1E17cm -3 To 5E19cm -3 , the magnesium doping concentration is 1E18cm -3 To 5E21cm -3 .

[0068] The fourth aspect of the present invention provides a method for manufacturing the epitaxial structure of the light-emitting diode of the second embodiment of the present invention, the method comprising: forming an unintentionally doped layer 121, a first semiconductor layer 122, a first barrier layer 123, a second barrier layer 124, a multi-quantum well layer 125 and a second semiconductor layer 126 stacked in sequence on a substrate 110.

[0069] The unintentional doping layer 121, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, the multi-quantum well layer 125 and the second semiconductor layer 126 are carbon-doped respectively, and the carbon doping concentrations are the same or different. Specifically, the carbon doping concentration of the unintentional doping layer 121 is ≤ the carbon doping concentration of the multi-quantum well layer 125 ≤ the carbon doping concentration of the first barrier layer 123 ≤ the carbon doping concentration of the first semiconductor layer 122 ≤ the carbon doping concentration of the second barrier layer 124 ≤ the carbon doping concentration of the second semiconductor layer 126. The carbon doping concentrations in the unintentional doping layer 121, the multi-quantum well layer 125, the first barrier layer 123, the first semiconductor layer 122, the second barrier layer 124 and the second semiconductor layer 126 increase in a gradual gradient.

[0070] Further, the unintentional doped layer 121, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, and the multi-quantum well layer 125 are respectively doped with silicon, and the second semiconductor layer 126 is doped with magnesium. The silicon doping concentrations of the unintentional doped layer 121, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124, and the multi-quantum well layer 125 are the same or different. Specifically, the silicon doping concentration of the unintentional doped layer 121 is ≤ the silicon doping concentration of the multi-quantum well layer 125 ≤ the silicon doping concentration of the first barrier layer 123 ≤ the silicon doping concentration of the second barrier layer 124 ≤ the silicon doping concentration of the first semiconductor layer 122.

[0071] In a specific embodiment, the carbon doping concentration of the unintentionally doped layer 121 is 1E16 cm -3 To 4E16cm -3, the silicon doping concentration is 1E17cm -3 To 1E20cm -3 ; The carbon doping concentration of the first semiconductor layer 122 is 4E16cm -3 To 1E17cm -3 , the silicon doping concentration is 1E19cm -3 To 1E20cm -3 ; The carbon doping concentration of the first barrier layer 123 is 4E16cm -3 To 1E17cm -3 , the silicon doping concentration is 5E17cm -3 To 1E19cm -3 ; The carbon doping concentration of the second barrier layer 124 is 3E17cm -3 To 5E18cm -3 , the silicon doping concentration is 5E17cm -3 To 1E19cm -3 The carbon doping concentration of the multi-quantum well layer 125 is 1E16cm -3 To 1E18cm -3 , the silicon doping concentration is 1E17cm -3 To 1E18cm -3 The carbon doping concentration of the second semiconductor layer 126 is 1E17cm -3 To 5E19cm -3 , the magnesium doping concentration is 1E18cm -3 To 5E21cm -3 .

[0072] Figure 3 A schematic diagram of the structure of a light emitting diode according to a third embodiment of the present invention is shown. In this embodiment, the light emitting diode is a face-up structure, but it is not difficult to understand that in other embodiments, the light emitting diode may also be a flip-chip structure or a vertical structure.

[0073] like Figure 3 As shown, the light emitting diode includes an epitaxial structure first electrode 130 and a second electrode 140, wherein the epitaxial structure may be any one of the epitaxial structures in the first embodiment or the second embodiment, and this embodiment is described by taking the epitaxial structure in the second embodiment as an example. That is, the epitaxial structure includes an unintentionally doped layer 121, a first semiconductor layer 122, a first barrier layer 123, a second barrier layer 124, a multi-quantum well layer 125, and a second semiconductor layer 126 stacked in sequence on a substrate 110. The first electrode 130 is electrically connected to the first semiconductor layer 122, and the second electrode 140 is electrically connected to the second semiconductor layer 126.

[0074] in, Figure 4a and Figure 4bThe SIMS test results of carbon doping concentration and silicon doping concentration in the epitaxial structure of the light emitting diode of the third embodiment of the present invention are shown; Figure 4a The carbon doping concentration and the silicon doping concentration in the unintentionally doped layer 121, the first semiconductor layer 122, the first barrier layer 123, the second barrier layer 124 and the light emitting layer 125 are shown; Figure 4b The carbon doping concentration and the silicon doping concentration in the first barrier layer 123, the second barrier layer 124, the light emitting layer 125 and the second semiconductor layer 126 are shown; Figure 4a and Figure 4b As shown, the carbon doping concentration and silicon doping concentration of each semiconductor structure layer are the same or different. Specifically, the carbon doping concentration of the unintentional doping layer 121 is ≤ the carbon doping concentration of the multi-quantum well layer 125 ≤ the carbon doping concentration of the first barrier layer 123 ≤ the carbon doping concentration of the first semiconductor layer 122 ≤ the carbon doping concentration of the second barrier layer 124 ≤ the carbon doping concentration of the second semiconductor layer 126; and the silicon doping concentration of the unintentional doping layer 121 is ≤ the silicon doping concentration of the multi-quantum well layer 125 ≤ the silicon doping concentration of the first barrier layer 123 ≤ the silicon doping concentration of the second barrier layer 124 ≤ the silicon doping concentration of the first semiconductor layer 122.

[0075] Figure 5a and Figure 5b The comparison results of the package brightness and light efficiency of the epitaxial structure of the light emitting diode of the third embodiment of the present invention and the epitaxial structure of the light emitting diode in the prior art are shown; wherein, Figure 5a FIG. 1 is a comparison result of the package brightness of the epitaxial structure of the light emitting diode of the third embodiment of the present invention and the epitaxial structure of the light emitting diode in the prior art. Figure 5a As shown, under the condition of 3A current, the packaging brightness of the epitaxial structure of the light-emitting diode in the prior art is about 1121mW, and the packaging brightness of the epitaxial structure of the light-emitting diode in the third embodiment of the present invention is about 1382mW. The packaging brightness of the epitaxial structure of the light-emitting diode in the third embodiment of the present invention is improved by about 23% compared with the packaging brightness of the epitaxial structure of the light-emitting diode in the prior art. Figure 5b The comparison results of the light emitting diode epitaxial structure of the third embodiment of the present invention and the light emitting diode epitaxial structure in the prior art are shown in FIG. Figure 5b As shown, under the condition of 3A current, the luminous efficiency of the epitaxial structure of the light-emitting diode in the prior art is about 98.41 lm / W, and the luminous efficiency of the epitaxial structure of the light-emitting diode in the third embodiment of the present invention is about 119.58 lm / W. The luminous efficiency of the epitaxial structure of the light-emitting diode in the third embodiment of the present invention is improved by about 21% relative to the luminous efficiency of the epitaxial structure of the light-emitting diode in the prior art.

[0076] It can be seen from the above results that the embodiment of the present invention effectively improves the brightness and light efficiency of the light emitting diode by setting the carbon doping concentration and silicon doping concentration of each layer in the epitaxial structure.

[0077] Figure 6a and Figure 6b The cross-sectional views at various stages in the manufacturing process of the light emitting diode according to the third embodiment of the present invention are shown.

[0078] like Figure 6a As shown, an unintentionally doped layer 121 , a first semiconductor layer 122 , a first barrier layer 123 , a second barrier layer 124 , a multi-quantum well layer 125 and a second semiconductor layer 126 are formed on a substrate 110 and stacked in sequence.

[0079] like Figure 6b As shown, the second semiconductor layer 126 , the multi-quantum well layer 125 , the second barrier layer 124 and the first barrier layer 123 are etched to expose the surface of the first semiconductor layer 122 .

[0080] Furthermore, a first electrode 130 is formed on the surface of the first semiconductor layer 122, and a second electrode 140 is formed on the surface of the second semiconductor layer 126, forming a Figure 3 The light emitting diode shown in the figure, wherein the first electrode 130 is electrically connected to the first semiconductor layer 122 , and the second electrode 140 is electrically connected to the second semiconductor layer 126 .

[0081] The epitaxial structure of a light-emitting diode and the preparation method thereof provided in the embodiment of the present invention dopes carbon elements in each layer of the epitaxial structure, thereby improving the antistatic ability of the light-emitting diode and improving the luminous efficiency of the light-emitting diode.

[0082] Furthermore, by setting the carbon doping concentration and silicon doping concentration of each layer in the epitaxial structure, the rate of electron injection into the multi-quantum well layer is reduced, the probability of electron overflow from the multi-quantum well layer is reduced, and at the same time, the rate of hole injection into the multi-quantum well layer is increased, thereby reducing the difference in electron-hole concentration in the multi-quantum well layer, improving the consistency of electron and hole concentration in the multi-quantum well layer, preventing non-radiative recombination, and at the same time improving the overlap probability of electron-hole wave functions and the electron-hole recombination efficiency, thereby improving the luminous efficiency of the light-emitting diode.

[0083] Furthermore, the carbon doping concentration and the silicon doping concentration of each semiconductor structure layer in the epitaxial structure vary gradually to obtain better expansion of electrons and holes, which is beneficial to the uniform distribution of electrons and holes in the multi-quantum well layer.

[0084] According to the embodiments of the present invention as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An epitaxial structure of a light emitting diode, characterized in that: include: substrate; as well as A first semiconductor layer, a first barrier layer, a second barrier layer, a multi-quantum well layer and a second semiconductor layer are sequentially stacked on the substrate, wherein the doping types of the first barrier layer and the second semiconductor layer are opposite to each other, Among them, the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well and the second semiconductor layer are respectively carbon-doped, and the carbon doping concentration of the multi-quantum well layer is ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer.

2. The epitaxial structure of a light emitting diode according to claim 1, characterized in that: The first semiconductor layer, the first barrier layer, the second barrier layer, and the multi-quantum well layer are respectively doped with silicon, and the silicon doping concentrations are the same or different. The second semiconductor layer is doped with magnesium.

3. The epitaxial structure of a light emitting diode according to claim 2, characterized in that: The silicon doping concentration of the multi-quantum well layer is ≤ the silicon doping concentration of the first barrier layer ≤ the silicon doping concentration of the second barrier layer ≤ the silicon doping concentration of the first semiconductor layer.

4. The epitaxial structure of a light emitting diode according to claim 3, characterized in that: The carbon doping concentration of the first semiconductor layer is 4E16cm -3 To 1E17cm -3 ; The silicon doping concentration of the first semiconductor layer is 1E19cm -3 To 1E20cm -3 .

5. The epitaxial structure of a light emitting diode according to claim 3, characterized in that: The carbon doping concentration of the first barrier layer is 4E16cm -3 To 1E17cm -3 ; The silicon doping concentration of the first barrier layer is 5E17cm -3 To 1E19cm -3 .

6. The epitaxial structure of a light emitting diode according to claim 3, characterized in that: The carbon doping concentration of the second barrier layer is 3E17cm -3 To 5E18cm -3 The silicon doping concentration of the second barrier layer is 5E17cm -3 To 1E19cm -3 .

7. The epitaxial structure of a light emitting diode according to claim 3, characterized in that: The carbon doping concentration of the multi-quantum well layer is 1E16cm -3 To 1E18cm -3 The silicon doping concentration of the multi-quantum well layer is 1E17cm -3 To 1E18cm -3 .

8. The epitaxial structure of a light emitting diode according to claim 3, characterized in that: The carbon doping concentration of the second semiconductor layer is 1E17cm -3 To 5E19cm -3 The magnesium doping concentration of the second semiconductor layer is 1E18cm -3 To 5E21cm -3 .

9. The epitaxial structure of a light emitting diode according to claim 1, characterized in that: Also included is an unintentional doping layer, wherein the unintentional doping layer is located between the substrate and the first semiconductor layer.

10. The epitaxial structure of a light emitting diode according to claim 9, characterized in that: The unintentional doping layer is carbon-doped, and the carbon doping concentration of the unintentional doping layer ≤ the carbon doping concentration of the multi-quantum well layer ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer.

11. The epitaxial structure of a light emitting diode according to claim 10, characterized in that: The unintentional doping layer is silicon-doped, and the silicon doping concentration of the unintentional doping layer is ≤ the silicon doping concentration of the multi-quantum well layer ≤ the silicon doping concentration of the first barrier layer ≤ the silicon doping concentration of the second barrier layer ≤ the silicon doping concentration of the first semiconductor layer.

12. The epitaxial structure of a light emitting diode according to claim 11, characterized in that: The carbon doping concentration of the unintentionally doped layer is 1E16 cm -3 To 4E16cm -3 The silicon doping concentration of the unintentionally doped layer is 1E17cm -3 To 1E20cm -3 .

13. The epitaxial structure of a light emitting diode according to claim 9, characterized in that: The unintentionally doped layer, the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well layer and the second semiconductor layer are at least one of GaN, AlN, InN, AlGaN, AlInN, InGaN, AlInGaN, GaN / InN superlattice, GaN / AlN superlattice, InN / GaN superlattice, GaN / AlGaN superlattice, GaN / AlInN superlattice, GaN / InGaN superlattice, GaN / AlInGaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInN superlattice, InGaN / AlInGaN superlattice, AlGaN / AlInN superlattice, AlGaN / AlInGaN superlattice, AlInGaN / AlInGaN superlattice, InGaN / GaN shallow quantum well, InGaN / AlGaN shallow quantum well and InGaN / AlInGaN shallow quantum well.

14. A method for manufacturing an epitaxial structure of a light emitting diode, characterized in that: include: Forming a first semiconductor layer, a first barrier layer, a second barrier layer, a multi-quantum well layer and a second semiconductor layer stacked in sequence on a substrate, wherein the doping types of the first barrier layer and the second semiconductor layer are opposite to each other; Among them, the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well and the second semiconductor layer are respectively carbon-doped, and the carbon doping concentration of the multi-quantum well layer is ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer.

15. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 14, characterized in that: The first semiconductor layer, the first barrier layer, the second barrier layer, and the multi-quantum well layer are doped with silicon respectively, and the silicon doping concentrations are the same or different. The second semiconductor layer is doped with magnesium.

16. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 15, characterized in that: The silicon doping concentration of the multi-quantum well layer is ≤ the silicon doping concentration of the first barrier layer ≤ the silicon doping concentration of the second barrier layer ≤ the silicon doping concentration of the first semiconductor layer.

17. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 16, characterized in that: The carbon doping concentration of the first semiconductor layer is 4E16cm -3 To 1E17cm -3 ; The silicon doping concentration of the first semiconductor layer is 1E19cm -3 To 1E20cm -3 .

18. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 16, characterized in that: The carbon doping concentration of the first barrier layer is 4E16cm -3 To 1E17cm -3 ; The silicon doping concentration of the first barrier layer is 5E17cm -3 To 1E19cm -3 .

19. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 16, characterized in that: The carbon doping concentration of the second barrier layer is 3E17cm -3 To 5E18cm -3 The silicon doping concentration of the second barrier layer is 5E17cm -3 To 1E19cm -3 .

20. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 16, characterized in that: The carbon doping concentration of the multi-quantum well layer is 1E16cm -3 To 1E18cm -3 The silicon doping concentration of the multi-quantum well layer is 1E17cm -3 To 1E18cm -3 .

21. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 16, characterized in that: The carbon doping concentration of the second semiconductor layer is 1E17cm -3 To 5E19cm -3 The magnesium doping concentration of the second semiconductor layer is 1E18cm -3 To 5E21cm -3 .

22. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 14, characterized in that: Also included is an unintentional doping layer, wherein the unintentional doping layer is located between the substrate and the first semiconductor layer.

23. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 22, characterized in that: The unintentional doping layer is carbon-doped, and the carbon doping concentration of the unintentional doping layer ≤ the carbon doping concentration of the multi-quantum well layer ≤ the carbon doping concentration of the first barrier layer ≤ the carbon doping concentration of the first semiconductor layer ≤ the carbon doping concentration of the second barrier layer ≤ the carbon doping concentration of the second semiconductor layer.

24. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 23, characterized in that: The unintentional doping layer is silicon-doped, and the silicon doping concentration of the unintentional doping layer is ≤ the silicon doping concentration of the multi-quantum well layer ≤ the silicon doping concentration of the first barrier layer ≤ the silicon doping concentration of the second barrier layer ≤ the silicon doping concentration of the first semiconductor layer.

25. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 24, characterized in that: The carbon doping concentration of the unintentionally doped layer is 1E16 cm -3 To 4E16cm -3 The silicon doping concentration of the unintentionally doped layer is 1E17cm -3 To 1E20cm -3 .

26. The method for manufacturing an epitaxial structure of a light emitting diode according to claim 22, characterized in that: The unintentionally doped layer, the first semiconductor layer, the first barrier layer, the second barrier layer, the multi-quantum well layer and the second semiconductor layer are at least one of GaN, AlN, InN, AlGaN, AlInN, InGaN, AlInGaN, GaN / InN superlattice, GaN / AlN superlattice, InN / GaN superlattice, GaN / AlGaN superlattice, GaN / AlInN superlattice, GaN / InGaN superlattice, GaN / AlInGaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInN superlattice, InGaN / AlInGaN superlattice, AlGaN / AlInN superlattice, AlGaN / AlInGaN superlattice, AlInGaN / AlInGaN superlattice, InGaN / GaN shallow quantum well, InGaN / AlGaN shallow quantum well and InGaN / AlInGaN shallow quantum well.

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