Light emitting diode and light emitting device

Abstract

The application provides a light emitting diode and a light emitting device, wherein the N-type semiconductor layer comprises a first structure layer and a second structure layer which are stacked in sequence, the vertical distance D between the first interface between the second structure layer and the first structure layer and the second interface between the N-type semiconductor layer and the active layer is between 0.01 microns and 0.2 microns. The side of the first structure layer away from the active layer is the light emitting side of the light emitting diode, and the vertical distance makes the distance between the light emitting side and the active layer small, reduces the propagation distance of photons, and is beneficial to the emission of photons from the light emitting side. On the other hand, the N-type semiconductor layer comprises the first structure layer and the second structure layer, and no other redundant material layer, so that the material layer is reduced, and the absorption of light is reduced, and more photons are emitted. The above can improve the light emitting efficiency of the light emitting diode.

Description

Technical Field

[0001] This invention relates to the field of semiconductor devices and apparatus, and particularly to a light-emitting diode and a light-emitting device. Background Technology

[0002] Micro-LEDs, due to their small size, high efficiency, and excellent performance, have broad prospects in fields such as displays. Traditional AlGaInP-based LED epitaxial structures typically include an N-type confinement layer, an N-type space layer, a multiple quantum well emitting layer, a P-type space layer, and a P-type confinement layer. The N-type confinement layer (usually AlInP) is used to confine charge carriers. However, for Micro-LEDs, especially devices smaller than 100 micrometers with a horizontal structure, existing structures have the following problems: First, due to the large carrier diffusion length, they easily diffuse to the chip sidewalls and undergo nonradiative recombination; second, at low current densities (e.g., less than 10 A / cm²), 2 Under these conditions, the probability of hole leakage is relatively small, and the confinement of holes by the N-type confinement layer is close to saturation. Furthermore, the band gap of the N-type confinement layer is usually larger than that of the adjacent semiconductor layer, and the refractive index is smaller than that of the adjacent semiconductor layer, which causes photons to undergo total internal reflection and be absorbed at the interface, reducing the light extraction efficiency and external quantum efficiency. Summary of the Invention

[0003] In view of the above-mentioned defects in the light emission efficiency of micro light-emitting diodes in the prior art, the present invention provides a light-emitting diode and a light-emitting device to solve one or more of the above problems.

[0004] One embodiment of this application provides a light-emitting diode, which includes at least: A semiconductor stack, comprising an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked sequentially; The N-type semiconductor layer includes a first structural layer and a second structural layer stacked sequentially, with a first interface between the second structural layer and the first structural layer, and a second interface between the N-type semiconductor layer and the active layer, wherein the vertical distance D between the first interface and the second interface is between 0.01 μm and 0.2 μm.

[0005] One embodiment of this application provides a light-emitting diode, which includes at least: a semiconductor stack, the semiconductor stack comprising an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked sequentially; The N-type semiconductor layer includes an N-type window layer and an N-type space layer stacked sequentially, with the N-type window layer and the N-type space layer in direct contact.

[0006] Another embodiment of this application provides a light-emitting device, which includes: a circuit board and at least one light-emitting diode fixed to the circuit board, the light-emitting diode including the light-emitting diode provided in this application.

[0007] As described above, the light-emitting diode and light-emitting device of this application have the following beneficial effects: The light-emitting diode (LED) of this application comprises an N-type semiconductor layer consisting of a first structural layer and a second structural layer stacked sequentially. The vertical distance D between the first interface between the second structural layer and the first structural layer and the second interface between the N-type semiconductor layer and the active layer is between 0.01 μm and 0.2 μm. The side of the first structural layer furthest from the active layer is the light-emitting side of the LED. The aforementioned vertical distance reduces the distance between the light-emitting side and the active layer, decreasing the photon propagation distance and facilitating photon emission from the light-emitting side. Furthermore, the N-type semiconductor layer, consisting of the first and second structural layers without any other redundant material layers, reduces total internal reflection at the interfaces between different material layers, further increasing photon emission. All of these factors contribute to improving the light extraction efficiency of the LED. Attached Figure Description

[0008] Figure 1 The diagram shown is a schematic diagram of the epitaxial structure of a light-emitting diode in the prior art.

[0009] Figure 2 The diagram shown is a schematic diagram of the structure of a light-emitting diode provided in Embodiment 1 of this application.

[0010] Figure 3 Displayed as Figure 2 The diagram shows a schematic of the semiconductor stack structure of a light-emitting diode.

[0011] Figure 4 Displayed as Figure 3 The concentration curves of some components in a partial semiconductor stack are shown.

[0012] Figure 5 Displayed as Figure 2 The diagram shows a process flow chart for manufacturing a light-emitting diode.

[0013] Figure 6 The diagram shows a structure in which semiconductor stacks are formed on a growth substrate.

[0014] Figure 7 Displayed as removal Figure 6 The diagram shows the structure of the growth substrate.

[0015] Figure 8 Displayed as Figure 2 The light-emitting diode shown is Figure 1 The diagram shows a comparison of the performance of LEDs.

[0016] Figure 9 The diagram shown is a schematic diagram of the light-emitting device provided in Embodiment 2 of the present invention.

[0017] Component designation explanation

[0018] 01. N-type layer; 02. Active layer; 03. P-type layer; 11. Window layer; 12. Constraint layer; 13. Spatial layer.

[0019] 100. Light-emitting diode; 101. Light-emitting side; 102. Electrode side; 110. Semiconductor stack; 111. N-type semiconductor layer; 1111. First structural layer; 1112. Second structural layer; 1113. First interface; 1114. Second interface; 1115. Buffer layer; 1116. First cutoff layer; 1117. Second cutoff layer; 112. Active layer; 1121. Well layer; 1122. Barrier layer; 113. P-type semiconductor; 1131. P-type space layer; 1132. P-type confinement layer; 1133. P-type transition layer; 1134. P-type window layer; 1135. P-type ohmic contact layer; 114. Electrode mesa; 115. Growth substrate; 120. First electrode; 130. Second electrode; 140. Insulating protective layer.

[0020] 300, Light-emitting device; 301, Circuit board; 302, Light-emitting diode. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0022] like Figure 1 As shown, in the prior art, a Micro-LED chip typically includes an N-type layer 01, an active layer 02, and a P-type layer 03 stacked sequentially. The N-type layer 01 includes a window layer 11, a confinement layer 12, and a space layer 13. This Micro-LED emits light from the window layer 11 side of the N-type layer 01, and the positive and negative electrodes are on the same side, both facing the P-end. The operating current density of this Micro-LED is less than 10 A / cm². 2The current tends to conduct along the sidewalls from the P-type layer 03 to the N-type layer 01. Electrons and holes recombine nonradiatively through the sidewall defect energy levels, reducing the confinement effect of the N-type confinement layer on holes. Furthermore, since the bandgap of confinement layer 12 is typically larger than that of window layer 11 and space layer 13, and its refractive index is lower, some photons incident at large angles undergo total internal reflection at the interface between space layer 13 and confinement layer 12. Additionally, the impurity energy levels in confinement layer 12 also partially absorb photons, further reducing the light extraction efficiency.

[0023] To address the aforementioned problems of existing light-emitting diodes (LEDs), this application provides a light-emitting diode comprising at least: A semiconductor stack, comprising an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked sequentially; The N-type semiconductor layer includes a first structural layer and a second structural layer stacked sequentially. A first interface is provided between the second structural layer and the first structural layer, and a second interface is provided between the N-type semiconductor layer and the active layer. The vertical distance D between the first interface and the second interface is between 0.01 μm and 0.2 μm.

[0024] As described above, the distance between the light-emitting surface of the LED (i.e. the side of the first structural layer away from the active layer) and the active layer is reduced, making the active region closer to the first structural layer, reducing the propagation distance of photons, thereby reducing the absorption of photons and improving the light extraction efficiency.

[0025] Optionally, the first structural layer and the second structural layer are in direct contact, wherein the first structural layer is an N-type window layer and the second structural layer is an N-type space layer.

[0026] As shown above, the absence of a confinement layer or other semiconductor layer between the window layer and the space layer of the N-type semiconductor layer in a light-emitting diode (LED) reduces the thickness of the N-type semiconductor layer, thereby reducing light absorption and improving light extraction efficiency. Furthermore, the reduction in material layers on one side of the N-type semiconductor layer shortens the epitaxial growth time of the semiconductor stack, reduces surface defects, and lowers epitaxial growth costs.

[0027] Optionally, the first structural layer is (Al) x1 Ga 1-x1 ) z3 In 1-z3 P material layer, wherein 0.3≤x1≤1, 0.45≤z3≤0.55. Optionally, the second structural layer is (Al). x2 Ga 1-x2 ) z4 In 1-z4Material layer P, wherein 0.3 ≤ x2 ≤ 1, 0.45 ≤ z4 ≤ 0.55. Optionally, in the first and second structural layers, 0 ≤ x2 - x1 ≤ 0.7. The above material layer selection is based on a strength less than 10 A / cm. 2 At current densities of [specific value], holes in the active region can be effectively confined, carrier leakage suppressed, and radiative recombination efficiency improved. Simultaneously, the absence of drastic band abrupt changes and low carrier transport resistance ensure low series resistance and forward voltage. Furthermore, similar Al composition materials effectively reduce interlayer interface light reflection and total internal reflection losses, guiding photons outward and significantly improving light extraction efficiency. In addition, the similar value ranges of the two compositions result in low interlayer lattice mismatch, significantly reducing interface stress and mismatch dislocations, thus decreasing defect-induced light absorption and non-radiative recombination. The gradual change in epitaxial growth parameters leads to better interface quality and process stability, ultimately improving device luminescence performance, operational stability, and mass production consistency.

[0028] The specific Al content settings in the first and second material layers result in a smaller difference in the bandgap between them, and consequently, a smaller difference in their refractive indices. Therefore, photons incident at large angles do not undergo total internal reflection at the interface but instead exit through the first material layer, thus improving light extraction efficiency. The refractive indices of the two material layers are continuous or approximately equal, with no obvious optical interface. Photons propagate forward with almost no reflection or scattering, resulting in direct light emission and significantly improved light extraction efficiency. Furthermore, the small difference in Al content between the two material layers, with the AlGaInP quaternary composition gradually varying or nearly identical, leads to better lattice matching, significantly reducing interface stress and mismatch dislocations. Consequently, non-radiative recombination is reduced, increasing the total light emission from the active region and ultimately increasing the light extraction amount of the LED, further enhancing its light extraction performance.

[0029] Optionally, the active layer comprises a plurality of alternately stacked periodic well layers and barrier layers, the barrier layers comprising (Al) y2 Ga 1-y2 ) z2 In 1-z2 P material layer, where 0.5≤y2≤1, 0.45≤z2≤0.55.

[0030] The active layer has a nearly identical Al content to the first and second structural layers, resulting in minimal differences in refractive index between the layers. This allows for the formation of a nearly continuous optical medium without abrupt interfaces. When photons propagate within the chip, Fresnel reflection and interface scattering occur almost nonexistently, significantly reducing the probability of light being trapped and improving light extraction efficiency. Furthermore, the similar Al composition content results in a correspondingly small band structure difference, leading to low carrier transport resistance, high mobility, lower device operating voltage, and reduced power consumption.

[0031] Optionally, the doping concentration of the N-type dopant in the N-type semiconductor layer has a concentration curve, which is approximately a straight line in the first structural layer and drops sharply after entering the second structural layer from the first structural layer.

[0032] Optionally, the doping concentration of the N-type dopant in the N-type semiconductor layer is M (1 ± 5%), where M is between 1E+17 atoms / cm². 3 ~1E+19atoms / cm 3 .

[0033] The N-type (e.g., Si) doping concentration curve in the first structural layer of an N-type semiconductor layer is approximately a straight line, meaning the doping concentration remains continuous and stable without sharp increases or decreases. On one hand, the smooth transition of carrier concentration eliminates the transport barrier caused by abrupt doping changes, optimizes current transport characteristics, effectively reduces device series resistance and forward operating voltage, and decreases power consumption. Simultaneously, it avoids carrier accumulation at interlayer boundaries, significantly reducing non-radiative recombination losses at the interface and improving the device's quantum efficiency. On the other hand, the uniform doping distribution makes the current diffusion within the chip more balanced, suppressing current crowding effects, significantly improving luminescence uniformity, and reducing localized heat generation. Furthermore, stable doping conditions simplify epitaxial growth control, reduce the probability of interface defects, further optimize crystal quality, and improve the long-term operational stability and product performance consistency of the device.

[0034] Another aspect of this application provides a light-emitting diode, which includes at least: a semiconductor stack, the semiconductor stack comprising an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked sequentially; The N-type semiconductor layer includes an N-type window layer and an N-type space layer stacked sequentially, with the N-type window layer and the N-type space layer in direct contact.

[0035] As mentioned above, the N-type semiconductor layer of the light-emitting diode does not have an N-type confinement layer. Instead, window layers and space layers with similar Al composition are directly grown. This can eliminate interface reflection, optical waveguide confinement, and defect absorption caused by large refractive index differences, allowing the emitted photons to propagate outward more smoothly. This significantly reduces the light loss between the interfaces of the internal multilayer materials, especially reducing the light absorption caused by the N-type confinement layer, ultimately improving the external quantum efficiency and light output brightness of the LED.

[0036] Another embodiment of the present invention provides a light-emitting device, which includes: a circuit board and at least one light-emitting diode fixed to the circuit board, the light-emitting diode including the light-emitting diode provided in this application.

[0037] The light-emitting device includes the light-emitting diode provided in this application, thus having high light extraction efficiency and brightness, and its display effect is greatly improved.

[0038] Example 1

[0039] This embodiment provides a light-emitting diode 100, such as Figure 2 As shown, the light-emitting diode 100 includes at least a semiconductor stack 110, which includes at least an N-type semiconductor layer 111, an active layer 112, and a P-type semiconductor layer 113 stacked sequentially. In an optional embodiment, the semiconductor stack 110 is an AlGaInP-based semiconductor stack 110, and the side of the N-type semiconductor layer 111 furthest from the active layer 112 is the light-emitting side 101. The N-type semiconductor layer 111 is optionally an N-type AlGaInP layer, used to provide electrons. The N-type AlGaInP layer provides electrons by doping with N-type impurities, such as Si, Ge, Sn, Se, and Te. The P-type semiconductor layer 113 is optionally a P-type AlInP or AlGaInP layer, providing holes by doping with P-type impurities, such as Mg, Zn, Ca, Sr, C, and Ba. In this embodiment, the N-type impurity is preferably Si, and the P-type impurity is preferably Mg or C.

[0040] Similarly, refer to Figure 2 and Figure 3 The N-type semiconductor layer 111 includes a first structural layer 1111 and a second structural layer 1112, wherein the second structural layer 1112 is adjacent to the active layer 112. A first interface 1113 is formed between the second structural layer 1112 and the first structural layer 1111, and a second interface 1114 is formed between the N-type semiconductor layer 111 and the active layer 112. The vertical distance D between the first interface 1113 and the second interface 1114 is between 0.01 μm and 0.2 μm. Further, the vertical distance D is between 0.01 μm and 0.08 μm, 0.1 μm and 0.15 μm, or 0.15 μm and 0.2 μm. In this embodiment, the distance between the light-emitting surface of the N-type semiconductor layer 111 (i.e., the side of the first structural layer 1111 away from the active layer 112) and the active layer 112 in the light-emitting diode 100 is reduced, making the active region closer to the first structural layer 1111, reducing the propagation distance of photons, thereby reducing the absorption of photons and improving the light extraction efficiency.

[0041] like Figure 2As shown, in this embodiment, the first structural layer 1111 and the second structural layer 1112 are in direct contact. In an optional example, the first structural layer 1111 is an N-type window layer, and the second structural layer 1112 is an N-type space layer. That is, in this embodiment, no other layer structure is provided between the first structural layer 1111 and the second structural layer 1112 of the N-type semiconductor layer 111. For example, no confinement layer or similar structure is provided between the N-type window layer and the N-type space layer. Therefore, the distance between the first interface 1113 and the second interface 1114 is reduced, that is, the propagation distance of photons in the light-emitting diode 100 is reduced, which helps to reduce photon absorption and improve the light extraction efficiency of the light-emitting diode 100.

[0042] In this embodiment, both the first structural layer 1111 and the second structural layer 1112 are AlGaInP material layers. Specifically, the first structural layer 1111 is (AlGaInP) material. x1 Ga 1-x1 ) z3 In 1-z3 The P material layer has the following properties: 0.3 ≤ x1 ≤ 1, 0.45 ≤ z3 ≤ 0.55; further, it can be 0.4 ≤ x1 ≤ 0.65, where x1 ≤ 0.6, and z3 can take values ​​such as 0.47, 0.53, 0.55, etc. The second structural layer 1112 is (Al) x2 Ga 1-x2 ) z4 In 1-z4 The P material layer has the following properties: 0.3 ≤ x2 ≤ 1, 0.45 ≤ z4 ≤ 0.55, further, 0.5 ≤ x2 ≤ 0.8, and even further, between 0.55 ≤ x2 ≤ 0.65 and 0.6 ≤ x2 ≤ 0.67. The value of z4 can be, for example, 0.47, 0.53, 0.55, etc. Furthermore, in the first structural layer 1111 and the second structural layer 1112, 0 ≤ x2 - x1 ≤ 0.7, and further, x2 - x1 can be 0.2, 0.5, 0.4, 0.7, etc. The selection of the above material layer is less than 10 A / cm. 2At a given current density, the device can effectively confine holes in the active region, suppress carrier leakage, and improve radiative recombination efficiency. Simultaneously, the absence of drastic band breaks and low carrier transport resistance ensure low series resistance and forward voltage. Furthermore, similar Al composition materials effectively reduce light reflection and total internal reflection losses at the interlayer interface, guiding photons outward and significantly improving light extraction efficiency. Moreover, the similar value ranges of the two compositions result in low interlayer lattice mismatch, significantly reducing interface stress and mismatch dislocations, thus decreasing defect-induced light absorption and non-radiative recombination. The gradual change in epitaxial growth parameters leads to better interface quality and process stability, ultimately improving the device's luminescent performance, operational stability, and mass production consistency. Furthermore, the Al composition content in the first and second material layers ensures that the difference in bandgap between the first structural layer 1111 and the second structural layer 1112 is less than 0.2 eV, and further, less than 0.1 eV.

[0043] In other words, combining Figure 4 , Figure 4 The left-hand vertical axis represents the concentrations of H, C, and O, as well as the doping concentrations of impurities such as Mg and Si. The right-hand vertical axis represents the relative intensities of components such as Al, P, Ga, As, and In. Therefore, it can be determined based on... Figure 4 The atomic percentage of the Al component is calculated using the ordinate and intensity curve on the right side of the graph. In this embodiment, the value of the ratio of the number of Al atoms to (the number of Al atoms + the number of Ga atoms) in the first structural layer 1111 and the second structural layer 1112 is between 30% and 100%, and the Al component content in the first structural layer 1111 and the second structural layer 1112 may be the same or different. In an optional example, the Al component content in the first structural layer 1111 and the second structural layer 1112 is different. Specifically, the value of the ratio of the number of Al atoms to (the number of Al atoms + the number of Ga atoms) in the first structural layer 1111 is between 30% and 100%, further between 40% and 80%, even further between 40% and 65%, and between 45% and 60%. The value of the ratio of the number of Al atoms to (the number of Al atoms + the number of Ga atoms) in the second structural layer 1112 is between 30% and 100%, further between 50% and 80%, even further between 55% and 65%, and even further between 60% and 67%. As described above, the Al content in the first structural layer 1111 and the second structural layer 1112 is basically the same, resulting in a small difference in the bandgap between them and a very small difference in the refractive index between the layers. Therefore, an approximately continuous optical medium can be formed without abrupt interfaces. When photons propagate inside the chip, Fresnel reflection and interface scattering hardly occur, greatly reducing the probability of light being trapped, which is beneficial to improving the light extraction efficiency. The similar Al composition content results in a correspondingly small bandgap, low carrier transport resistance, high migration efficiency, lower device operating voltage, and reduced power consumption.

[0044] In this embodiment, the thickness of the first structural layer 1111 is no greater than 10 μm, and further, it is between 1 μm and 10 μm. Even further, it is between 5 μm and 10 μm, or between 5 μm and 8 μm, or between 3 μm and 5 μm. The thickness of the second structural layer 1112 is no greater than 0.2 μm, and further, it is between 0.01 μm and 0.2 μm. Even further, it is between 0.01 μm and 0.08 μm, or between 0.1 μm and 0.15 μm. Limiting the thickness of the first structural layer 1111 significantly improves the lateral current expansion capability, suppresses current congestion, improves chip light emission uniformity, and reduces local temperature rise. On the other hand, it avoids problems such as additional light absorption, increased epitaxial stress, and increased thermal resistance caused by an excessively thick first structural layer 1111, thus controlling production costs and crystal defects. The thinner second structural layer 1112 can shorten the transmission path of photons and charge carriers, effectively reduce the material's bulk light absorption and non-radiative recombination loss, and suppress the local optical waveguide effect, which is conducive to the outward diffusion of the light field.

[0045] As described above, in this embodiment, the N-type semiconductor layer 111 has an N-type dopant, such as Si. The doping concentration of the N-type dopant is M (1 ± 5%), where M is between 1E+17 atoms / cm². 3 ~1E+19atoms / cm 3 Combining Figure 4 In this embodiment, the doping concentration of the N-type dopant has a concentration curve. The trend of this concentration curve is consistent, and the fluctuation range of the concentration curve is small, making the concentration curve approximately a straight line. That is, the doping concentration of the N-type dopant in the N-type semiconductor layer 111 is approximately a fixed value. Figure 4 As shown, in the first structural layer 1111 of the N-type semiconductor layer 111, the Si doping concentration remains continuous and stable, without any sharp increases or decreases in concentration. However, after entering the second structural layer 1112 from the first structural layer 1111, the concentration curve shows a sharp drop. For example... Figure 4 As shown, in the first structural layer 1111 of the N-type semiconductor layer 111, the Si doping concentration is approximately 5E+17 atoms / cm². 3The fluctuation range is no more than ±5%. After entering the second structural layer 1112, the concentration curve drops sharply, indicating a sudden drop. This means that the second structural layer 1112 does not contain intentionally doped N-type dopants. The aforementioned concentration curve of the N-type dopants, on the one hand, allows for a smooth transition in carrier concentration, eliminating the transport barrier caused by abrupt doping changes, optimizing current transport characteristics, effectively reducing device series resistance and forward operating voltage, and reducing power consumption; at the same time, it avoids carrier accumulation at interlayer interfaces, significantly reducing non-radiative recombination losses at the interface and improving the quantum efficiency within the device. On the other hand, the uniform doping distribution makes the current diffusion inside the chip more balanced, suppressing the current crowding effect, significantly improving luminescence uniformity, and reducing local heat generation in the device. In addition, stable doping conditions can simplify epitaxial growth control, reduce the probability of interface defects, further optimize crystal quality, and improve the long-term operating stability and product performance consistency of the device.

[0046] In this embodiment, the side of the first structural layer 1111 away from the second structural layer 1112 is the light-emitting side 101 of the light-emitting diode 100. In order to further enhance the light-emitting efficiency of the light-emitting diode 100, the surface of the first structural layer 1111 located on the light-emitting side 101 is formed as a roughened surface.

[0047] Refer again Figure 3 The active layer 112 of the light-emitting diode 100 includes multiple alternating periods of well layers 1121 and barrier layers 1122, wherein the well layer 1121 is adjacent to the second structural layer 1112. The number of periods of the well layers 11212 and barrier layers 1122 in the active layer 112 is typically between 1 and 20, and more specifically, between 3 and 5, 5 and 10, 5 and 20, or between 10 and 20. The single-layer thickness of the well layer 1121 is between 2 nm and 20 nm, and more specifically, between 3 nm and 10 nm or 4 nm and 5 nm; the single-layer thickness of the barrier layer 1122 is between 1 nm and 50 nm, and more specifically, between 4 nm and 15 nm or 5 nm and 10 nm. The total thickness of the active layer 112 is between 10 nm and 900 nm, and more specifically, between 10 nm and 150 nm.

[0048] In an optional example, well layer 1121 / barrier layer 1122 can be (Al) y1 Ga 1-y1 ) z1 In 1-z1 P / (Al y2 Ga 1-y2 ) z2 In 1-z2 P combination, wherein the Al component content in well layer 1121 is less than the Al component content in barrier layer 1122, i.e., y1 < y2. Further, well layer 1121 (Al y1 Ga1-y1 ) z1 In 1-z1 In P, the value of y1 is typically between 0 and 0.3, 0.45 ≤ z1 ≤ 0.55, and the value of z1 can be, for example, 0.47, 0.53, 0.55, etc. Further, y1 is between 0 and 0.1, and even further, y1 is typically 0, meaning the well layer 1121 is a GaInP layer. Barrier layer 1122 (Al y2 Ga 1-y2 ) z2 In 1-z2 In P, the value of y2 is usually between 0.5 and 1, and 0.45 ≤ z2 ≤ 0.55. The value of z2 can be, for example, 0.47, 0.53, 0.55, etc. Furthermore, y2 is between 0.5 and 0.8, or between 0.6 and 0.7.

[0049] In this embodiment, as Figure 3 As shown, in the direction away from the active layer 112, the P-type semiconductor layer 113 includes a P-type space layer 1131, a P-type confinement layer 1132, a P-type transition layer 1133, a P-type window layer 1134, and a P-type ohmic contact layer 1135 stacked sequentially. The P-type space layer 1131 is adjacent to the active layer 112 and is also an AlGaInP material. This P-type space layer 1131 is an unintentionally doped layer with a thickness of no more than 300 nm. The P-type confinement layer 1132 is typically an AlInP material layer with a thickness between 100 nm and 500 nm, wherein the P-type doping concentration is less than 1E+19 atoms / cm². 3 The p-type transition layer 1133 is also an AlGaInP-based material, with a p-type doping concentration of less than 1E+20 atoms / cm². 3, Its thickness is no greater than 50 nm. The p-type window layer 1134 is typically a GaP layer, in which the p-type doping concentration is less than 5E+19 atoms / cm. 3 Its thickness ranges from 100 nm to 1000 nm.

[0050] like Figure 2 As shown, the light-emitting diode 100 also includes an electrode structure and an insulating protective layer 140. Figure 2In the structure, the side opposite to the light-emitting side 101 is the electrode side 102 of the light-emitting diode 100. The semiconductor stack 110 forms an electrode mesa 114 on the electrode side 102. The electrode mesa 114 exposes the N-type semiconductor layer 111, and further exposes the first structural layer 1111 (N-type window layer) in the N-type semiconductor layer 111. The electrode structure includes a first electrode 120 and a second electrode 130. The first electrode 120 is located on the electrode mesa 114 to be electrically connected to the N-type semiconductor layer 111, and the second electrode 130 is located above the P-type semiconductor layer 113 on the electrode side 102 to be electrically connected to the P-type semiconductor layer 113 (specifically, the P-type window layer 1134).

[0051] An insulating protective layer 140 is located on the sidewall of the light-emitting diode 100 and on the surface of the exposed semiconductor stack 110 on the electrode side 102 (specifically, on the surface of the P-type semiconductor 113 layer and the surface of the electrode mesa 114) to protect the device from external impurities and moisture, thereby improving its service life. The insulating protective layer 140 can be one or any combination of SiO2, SiN, SiON, etc.

[0052] This embodiment also provides a method for manufacturing the above-mentioned light-emitting diode 100, such as... Figure 5 As shown, the manufacturing method includes the following steps: Step S100: Provide a growth substrate 115; Step S200: A semiconductor stack 110 is formed over the growth substrate 115; Step S300: Etch the semiconductor stack 110 to form an electrode mesa 114, and form an electrode structure on the electrode mesa 114 and the semiconductor stack 110; Step S400: Remove the growth substrate 115 to expose the N-type semiconductor layer 111 of the semiconductor stack 110, and etch the first structural layer 1111 of the exposed N-type semiconductor layer 111.

[0053] like Figure 6 As shown, a growth substrate 115 is provided, such as a GaAs substrate. Since the interface chemical bonds between the GaAs substrate and the AlGaInP semiconductor material layer are well matched, the grown AlGaInP epitaxial layer has almost no mismatch dislocations, resulting in high crystal quality, which is beneficial to ensuring the internal quantum efficiency of the formed light-emitting diode 100.

[0054] Similarly, Figure 6As shown, an N-type semiconductor layer 111, an active layer 112, and a P-type semiconductor layer 113 are sequentially grown on a growth substrate 115 to form a semiconductor stack 110. Specifically, before forming the N-type semiconductor layer 111, a buffer layer 1115, a first stop layer 1116, and a second stop layer 1117 are first formed. The buffer layer 1115 is an N-type doped GaAs layer with a thickness between 100 nm and 500 nm and a doping concentration of less than 1E+19 atoms / cm². 3 The first stop layer 1116 is an N-type doped GaInP layer with a thickness between 50 nm and 300 nm and a doping concentration of less than 1E+19 atoms / cm². 3 The second stop layer 1117 is an N-type doped GaAs layer with a thickness between 10 nm and 200 nm and a doping concentration of less than 1E+20 atoms / cm. 3 Then, a first structural layer 1111 and a second structural layer 1112 of an N-type semiconductor layer 111 are formed above the second cutoff layer 1117. The specific material composition of the first structural layer 1111 and the second structural layer 1112 can be referred to the above description of the light-emitting diode 100.

[0055] Subsequently, an active layer 112 is formed above the aforementioned second structural layer 1112. Specifically, a well layer 1121 and a barrier layer 1122 are alternately formed. The well layer 1121 and the barrier layer 1122 can be (Al) y1 Ga 1-y1 ) z1 In 1-z1 P / (Al y2 Ga 1-y2 ) z2 In 1-z2 For the P combination, the specific material selection and the number of alternating cycles can also refer to the above description of the light-emitting diode 100.

[0056] A P-type semiconductor layer 113 is formed above the active layer 112. Specifically, a P-type space layer 1131, a P-type confinement layer 1132, a P-type transition layer 1133, a P-type window layer 1134, and a P-type ohmic contact layer 1135 are formed sequentially. The selection of each material layer and the P-type doping concentration can also refer to the description of the light-emitting diode 100.

[0057] Then, refer to Figure 7 And can be referenced again. Figure 2The semiconductor stack 110 is etched from one side of the P-type semiconductor layer 113 until the N-type window layer in the N-type semiconductor layer 111 is exposed, forming an electrode mesa 114. A first electrode 120 and a second electrode 130 are formed above the electrode mesa 114 and the P-type semiconductor layer 113 of the semiconductor stack 110, respectively. An insulating protective layer 140 is formed on the sidewalls of the semiconductor stack 110 and on the exposed surfaces of the semiconductor stack 110 and the electrode mesa 114.

[0058] After that, just like Figure 7 As shown, the growth substrate 115 is removed from one side of the growth substrate 115. For example, the GaAs buffer layer 1115 can be removed by wet etching until it is completely etched. At this time, the first stop layer 1116 acts as an etching stop layer and is not damaged, while protecting the remaining semiconductor layers on it from damage. Then the first stop layer 1116 is removed to expose the second stop layer 1117.

[0059] Finally, you can refer to it again. Figure 2 The first structural layer 1111 is etched from the side of the second stop layer 1117. During this process, the thinner second stop layer 1117 is removed, and a roughened surface is formed on the side of the first structural layer 1111 away from the active layer 112.

[0060] To verify the optical characteristics of the light-emitting diode 100 described in this embodiment, the following will be performed: Figure 1 The prior art shown uses a light-emitting diode 100 as a comparative example. For instance... Figure 8 As shown, the forward voltage VF, external quantum efficiency (EQE), and photoelectric conversion efficiency (WPE) of each LED 100 are compared under different current densities. Figure 8 It can be seen that, regardless of whether the current density is low or high, the forward voltage of the LED 100 in this embodiment does not change significantly compared to the comparative example. That is, the forward voltage of the LED 100 having the semiconductor stack 110 described above in this embodiment is not affected. Compared to the comparative example, the EQE and WPE of this embodiment are improved to varying degrees at different current densities, especially at the typical low current of Micro-LEDs (0.5A / cm). 2 In this application, compared to the comparative example, the EQE of the light-emitting diode in this embodiment is improved by nearly 10%, and the WPE is improved by nearly 10%. It can be seen that the light-emitting diode in this embodiment has achieved a significant improvement in light extraction efficiency.

[0061] Example 2

[0062] This embodiment provides a light-emitting device, such as... Figure 9As shown, the light-emitting device 300 includes a circuit board 301 and at least one light-emitting diode 302 fixed to the circuit board 301. The light-emitting diode includes the light-emitting diode provided in Embodiment 1 of this application. Because the light-emitting device includes the light-emitting diode provided in Embodiment 1, it has good light emission effect and better reliability.

[0063] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A light-emitting diode, characterized in that, At least including: A semiconductor stack, comprising an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked sequentially; The N-type semiconductor layer includes a first structural layer and a second structural layer stacked sequentially. There is a first interface between the second structural layer and the first structural layer, and a second interface between the N-type semiconductor layer and the active layer. The vertical distance D between the first interface and the second interface is between 0.01 μm and 0.2 μm.

2. The light-emitting diode according to claim 1, characterized in that, The first structural layer is in direct contact with the second structural layer, wherein the first structural layer is an N-type window layer and the second structural layer is an N-type space layer.

3. The light-emitting diode according to claim 1, characterized in that, The first structural layer is (Al) x1 Ga 1-x1 ) z3 In 1-z3 P material layer, where 0.3≤x1≤1, 0.45≤z3≤0.

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4. The light-emitting diode according to claim 3, characterized in that, The second structural layer is (Al) x2 Ga 1-x2 ) z4 In 1-z4 P material layer, where 0.3≤x2≤1, 0.45≤z4≤0.

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5. The light-emitting diode according to claim 4, characterized in that, In the first structural layer and the second structural layer, 0 ≤ x2 - x1 ≤ 0.

7.

6. The light-emitting diode according to claim 1, characterized in that, The active layer comprises multiple alternately stacked periodic well layers and barrier layers, the barrier layer comprising (Al) y2 Ga 1-y2 ) z2 In 1-z2 P material layer, where 0.5≤y2≤1, 0.45≤z2≤0.

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7. The light-emitting diode according to claim 1, characterized in that, The doping concentration of the N-type dopant in the N-type semiconductor layer has a concentration curve, which is approximately a straight line in the first structural layer and drops sharply after entering the second structural layer from the first structural layer.

8. The light-emitting diode according to claim 1, characterized in that, The doping concentration of the N-type dopant in the N-type semiconductor layer is M (1 ± 5%), where M is between 1E+17 atoms / cm². 3 ~1E+19atoms / cm 3 .

9. A light-emitting diode, characterized in that, It includes at least: a semiconductor stack, wherein the semiconductor stack comprises an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked sequentially; The N-type semiconductor layer includes an N-type window layer and an N-type space layer stacked sequentially, with the N-type window layer and the N-type space layer in direct contact.

10. A light-emitting device, characterized in that, include: A circuit board and at least one light-emitting diode fixed to the circuit board, the light-emitting diode including the light-emitting diode according to any one of claims 1 to 9.

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