CN115411159A - Micro light-emitting device - Google Patents

Micro light-emitting device Download PDF

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Publication number
CN115411159A
CN115411159A CN202211137921.3A CN202211137921A CN115411159A CN 115411159 A CN115411159 A CN 115411159A CN 202211137921 A CN202211137921 A CN 202211137921A CN 115411159 A CN115411159 A CN 115411159A
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layer
type cladding
window
cladding layer
emitting device
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Inventor
方信乔
王信介
赖彦霖
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PlayNitride Inc
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PlayNitride Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/025—Physical imperfections, e.g. particular concentration or distribution of impurities
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/04—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
    • H01L33/06—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/14—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/16—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous

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

Abstract

The invention provides a micro light-emitting device, which comprises a first type cladding layer, a light-emitting layer, a second type cladding layer, a multi-layer window layer and at least one intermediate layer. The light emitting layer is located on the first type cladding layer, and the second type cladding layer is located on the light emitting layer. The light-emitting layer is located between the first type cladding layer and the second type cladding layer. The multi-layer window layer is located on the second type cladding layer. The interposer is located between two adjacent window layers. The ion doping concentration of the intermediate layer is less than or equal to that of the multi-layer window layer.

Description

Micro light-emitting device
Technical Field
The present disclosure relates to light emitting devices, and particularly to a micro light emitting device.
Background
In the development of light emitting diodes, researchers have developed high-brightness visible Light Emitting Diodes (LEDs), such as red LEDs, yellow LEDs, or orange LEDs, using aluminum gallium indium phosphide (AlGaInP). To solve the problem of non-uniform current distribution outside the ohm contact region, it is common practice to form a window layer (window layer) with gallium phosphide (GaP) on a p-type cladding layer (such as a p-type aluminum gallium indium phosphide layer). However, since the lattice constant of the window layer is not matched with the lattice constant of the p-type cladding layer, a dislocation defect (dislocation defect) with high distribution density is easily formed in the window layer, so that the leakage current (leakage current) of the led is increased, resulting in poor light emitting efficiency of the led.
Disclosure of Invention
The invention is directed to a micro light-emitting device with better light-emitting efficiency.
According to an embodiment of the present invention, the micro light-emitting device includes a first type cladding layer, a light-emitting layer, a second type cladding layer, a multi-layer window layer, and at least one intermediate layer. The light emitting layer is located on the first type cladding layer, and the second type cladding layer is located on the light emitting layer. The light emitting layer is located between the first type cladding layer and the second type cladding layer. The multi-layer window layer is located on the second type cladding layer. The medium layer is positioned between the two adjacent window layers. The ion doping concentration of the intermediate layer is less than or equal to that of the multi-layer window layer.
According to another embodiment of the present invention, the micro light-emitting device includes a first type cladding layer, a light-emitting layer, a second type cladding layer, a multi-layer window layer, and at least one intermediate layer. The light emitting layer is located on the first type cladding layer, and the second type cladding layer is located on the light emitting layer. The light-emitting layer is located between the first type cladding layer and the second type cladding layer. The multi-layer window layer is located on the second type cladding layer, and the material of the multi-layer window layer has a first lattice constant. The interposer is located between two adjacent window layers, and the material of the interposer has a second lattice constant. The ratio of the second lattice constant to the first lattice constant is 1.01 times or more or 0.99 times or less.
In view of the above, in the micro light emitting device of the present invention, any two adjacent window layers are separated by an intermediate layer, and the intermediate layer can be used to block dislocation defects from being generated continuously from the lower window layer to the upper window layer, so as to reduce the dislocation defect density in the window layers and improve the leakage current. The leakage current is improved, which is helpful to improve the luminous efficiency of the micro light-emitting element.
Drawings
Fig. 1A, fig. 1B, fig. 2A, fig. 2B, fig. 3A to fig. 3D, fig. 4A, fig. 4B, fig. 5 and fig. 6 are schematic cross-sectional views of micro light-emitting devices according to different embodiments of the present invention;
fig. 7 is a schematic cross-sectional view of an epitaxial structure of a micro light-emitting device according to an embodiment of the invention.
Detailed Description
Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.
Fig. 1A, fig. 1B, fig. 2A, fig. 2B, fig. 3A to fig. 3D, fig. 4A, fig. 4B, fig. 5 and fig. 6 are schematic cross-sectional views of micro light-emitting devices according to different embodiments of the present invention. Referring to fig. 1A, in the present embodiment, the micro light emitting device 100 includes a first type cladding layer 110, a light emitting layer 120, a second type cladding layer 130, a first window layer 140, a second window layer 141, and an intermediate layer 150, wherein the first type cladding layer 110 may be a quaternary or ternary material, such as an n-type aluminum gallium indium phosphide layer or an aluminum indium phosphide layer, and the second type cladding layer 130 may be a quaternary or ternary material, such as a p-type aluminum gallium indium phosphide layer or an aluminum indium phosphide layer. The light-emitting layer 120 may have a Multi Quantum Well (MQW) structure, and is disposed on (or covered on) the first-type cladding layer 110. In addition, the second type cladding layer 130 is located on (or covers) the light emitting layer 120, and the light emitting layer 120 is located between the first type cladding layer 110 and the second type cladding layer 130.
The first type cladding layer 110, the light emitting layer 120 and the second type cladding layer 130 are sequentially stacked from bottom to top, and the first window layer 140, the intermediate layer 150 and the second window layer 141 are sequentially stacked on the second type cladding layer 130 from bottom to top. Further, the first window layer 140 is disposed on (or covers) the second type cladding layer 130, wherein the interposer 150 is disposed on (or covers) the first window layer 140, and the second window layer 141 is disposed on (or covers) the interposer 150. That is, the interposer 150 is located between the first window layer 140 and the second window layer 141, and separates the first window layer 140 from the second window layer 141. In addition, the first window layer 140 is closest to the second type cladding layer 130, and the second window layer 141 is relatively far away from the second type cladding layer 130.
The first window layer 140 and the second window layer 141 may be gallium phosphide (GaP) or indium phosphide (InP) window layers, and are used for diffusing current to improve the uniformity of current distribution outside the ohm contact region. In some embodiments, the material of the interposer 150 includes (Al) x Ga 1-x ) 1-y In y P, wherein 1. Gtoreq.x.gtoreq.0, and 1>y>0. In some embodiments, 1>x>0.5, and y>0.5, but not limited thereto. In some embodiments, the material of the interposer 150 includes SiC, alN, gaN, znO, beSe, mgS, beTe, gaAs, alAs, inP, mgSe, cdSe, or ZnTe.
In some embodiments, the first window layer 140, the second window layer 141, and the interposer 150 may be doped with metal ions (e.g., magnesium ions), wherein the ion doping concentration of the second window layer 141 is greater than that of the first window layer 140, and the ion doping concentration of the interposer 150 is equal to or less than that of the first window layer 140. In some embodiments, the first window layer 140 and the second window layer 141 can be doped with metal ions (e.g., magnesium ions), wherein the ion doping concentration of the second window layer 141 is greater than the ion doping concentration of the first window layer 140, and the ion doping concentration of the interposer 150 is 0, i.e., the interposer 150 is not doped with metal ions. Since the ion doping concentration of the first window layer 140 closest to the second type cladding layer 130 is lower, it is helpful to reduce the diffusion degree of the doping ions into the second type cladding layer 130.
As shown in fig. 1A, the micro light emitting device 100 further includes a first type electrode 101, a second type electrode 102 and a contact layer 103, wherein the contact layer 103 is located between the first type electrode 101 and the first type cladding layer 110, and the first type electrode 101 is electrically connected to the first type cladding layer 110 through the contact layer 103. On the other hand, the contact layer 103, the first type cladding layer 110, the light emitting layer 120, the second type cladding layer 130, the first window layer 140, the interposer 150 and the second window layer 141 are sequentially stacked from bottom to top, and the first window layer 140 is located between the interposer 150 and the second type cladding layer 130. In detail, the second type electrode 102 passes through the contact layer 103, the first type cladding layer 110, the light emitting layer 120 and the second type cladding layer 130, and is electrically connected to the first window layer 140. That is, the second type electrode 102 is electrically connected to the second type cladding layer 130 through the first window layer 140.
As shown in fig. 1A, the remaining outer surface of the micro light-emitting device 100 excluding the light-emitting surface is covered by an insulating layer 105. The first-type electrode 101 penetrates through the insulating layer 105 covering the contact layer 103 to electrically connect (or contact) the contact layer 103. In addition, the second-type electrode 102 passes through the contact layer 103, the first-type cladding layer 110, the light-emitting layer 120 and the second-type cladding layer 130, and is electrically connected to the first window layer 140. In addition, the sidewall of the portion of the second type electrode 102 located in the contact layer 103, the first type cladding layer 110, the light emitting layer 120, the second type cladding layer 130 and the first window layer 140 is covered by the insulating layer 105 to be electrically isolated from the contact layer 103, the first type cladding layer 110, the light emitting layer 120 and the second type cladding layer 130, but the end surface of the second type electrode 102 located in the first window layer 140 is not covered by the insulating layer 105 to be electrically connected to the first window layer 140.
In the present embodiment, the interposer 150 separates the first window layer 140 from the second window layer 141, and dislocation defects formed in the first window layer 140 due to the mismatch between the lattice constant of the first window layer 140 and the lattice constant of the second type cladding layer 130 can be blocked by the interposer 150. That is, the interposer 150 can be used to block dislocation defects from continuing to be generated from the first window layer 140 to the second window layer 141, so as to reduce the defect density of dislocations in the window layer, especially the defect density of dislocations in the second window layer 141, and improve the leakage current. The leakage current is improved, which is helpful to improve the light emitting efficiency of the micro light emitting device 100.
Specifically, the first window layer 140 is closer to the second type cladding layer 130 than the second window layer 141, and the defect density of dislocations in the second window layer 141 is reduced under the blocking of the interposer 150. That is, the defect density of the dislocations in the first window layer 140 is greater than the defect density of the dislocations in the second window layer 141. For example, the ratio of the defect density of the dislocations in the first window layer 140 to the defect density of the dislocations in the second window layer 141 is between 2 and 100, so that more current can be conducted in the second window layer 141 with a lower defect density.
In some embodiments, the sum of the thickness T1 of the first window layer 140 and the thickness T2 of the second window layer 141 may be more than 50 times and less than 1500 times, for example, 200 times or 700 times, the thickness T3 of the interposer 150. In some embodiments, the thickness T2 of the second window layer 141 is greater than the thickness T1 of the first window layer 140, and may be 2.5 times or more and 10 times or less the thickness T1 of the first window layer 140. As a result, the characteristics of the whole window layer are more dependent on the second window layer 141 with a higher thickness, and even the window layers above the third layer, not the first window layer 140, which significantly reduces the dislocation defect density in the whole window layer.
In some embodiments, the thickness T1 of the first window layer 140 may be less than or equal to 1500 nm. In some embodiments, the second window layer 141 is farther from the second type cladding layer 130 than the first window layer 140, and is used as a window layer of the farthest second type cladding layer 130, wherein a thickness T2 of the second window layer 141 may be more than 0.7 times a sum of the thickness T1 of the first window layer 140, the thickness T2 of the second window layer 141, and the thickness T3 of the interposer 150. In some embodiments, the thickness T3 of the interposer 150 is less than or equal to 100 nm, and may be between 6 nm and 30 nm, for example, 10 nm, which may easily cause defects in the interposer 150 itself if the thickness of the interposer 150 is too large, and conversely, if the thickness is too thin, the defects generated from the first window layer 140 continuing to the second window layer 141 cannot be blocked.
In some embodiments, the lattice constant of the first window layer 140 and the second window layer 141 is equal to or greater than 5.45 angstroms, the lattice constant of the interposer 150 is equal to or greater than 5.5045 angstroms (e.g., equal to or greater than 1.01 times the lattice constant of the first window layer 140 and the second window layer 141) or equal to or less than 5.3955 angstroms (e.g., equal to or less than 0.99 times the lattice constant of the first window layer 140 and the second window layer 141), and for example, the lattice constant of the interposer 150 is equal to or greater than 5.5045 angstroms, the lattice constant of the interposer 150 is preferably equal to or greater than 5.65 angstroms.
In some embodiments, the materials of the first window layer 140 and the second window layer 141 have a first lattice constant, and the material of the interposer 150 has a second lattice constant. The second lattice constant may be more than 1.01 times the first lattice constant, or less than 0.99 times the second lattice constant. In some embodiments, the second lattice constant may be greater than or equal to 1.02 times the first lattice constant, or less than or equal to 0.98 times the second lattice constant. In some embodiments, the second lattice constant may be greater than or equal to 1.03 times the first lattice constant, or less than or equal to 0.97 times the second lattice constant.
In some embodiments, the material of the first window layer 140 and the second window layer 141 has a first lattice constant of 5.45 angstroms, and the material of the interposer 150 has a second lattice constant of 5.65 angstroms. In some embodiments, the material of the first window layer 140 and the second window layer 141 is GaP, and the material of the interposer 150 is Al 0.5 In 0.5 And P. In some embodiments, the lattice constant difference between the interposer 150 and the first window layer 140 (or the second window layer 141) is larger than the lattice constant difference between the second type cladding layer 130 and the first window layer 140 (or the second window layer 141), so as to enhance the effect of blocking dislocation defects generated from the first window layer 140 to the second window layer 141.
The micro light-emitting device 100A shown in fig. 1B is similar to the micro light-emitting device 100 shown in fig. 1A, except that: as shown in fig. 1B, the micro light-emitting device 100A further includes a third window layer 142 on the second window layer 141, and the interposer includes a first interposer 151 and a second interposer 152 separated from each other. The first interposer 151 is located between the first window layer 140 and the second window layer 141, and the second interposer 152 is located between the second window layer 141 and the third window layer 142.
That is, the first window layer 140 and the second window layer 141 are separated by the first interposer 151, and the second window layer 141 and the third window layer 142 are separated by the second interposer 152. Therefore, the first interposer 151 may be used to block the generation of the dislocation defect from the first window layer 140 to the second window layer 141, and the second interposer 152 may be used to block the generation of the dislocation defect from the second window layer 141 to the third window layer 142. Therefore, the defect density of the dislocations in the third window layer 142 farthest from the second type cladding layer 130 is less than the defect density of the dislocations in the second window layer 141, and the defect density of the dislocations in the second window layer 141 is less than the defect density of the dislocations in the first window layer 140. In other words, the defect density of the dislocations in the window layer closest to the second type cladding layer 130 is greater than the defect density of the dislocations in the remaining window layers.
As shown in fig. 1B, the first interposer 151 is closer to the second type cladding layer 130 than the second interposer 152, and the thickness T31 of the first interposer 151 is greater than the thickness T32 of the second interposer 152, but the thickness relationship between the two is not limited thereto. In addition, the ion doping concentration of the first window layer 140 is less than the ion doping concentration of the second window layer 141 and the ion doping concentration of the third window layer 142.
The micro light-emitting device 100B shown in fig. 2A is similar to the micro light-emitting device 100 shown in fig. 1A, except that: as shown in fig. 2A, the interposer includes an interposer layer 150a and an interposer layer 150b connected together. In some embodiments, the intermediate layer 150a is closer to the second type cladding layer 130 than the intermediate layer 150b, and the thickness T33 of the intermediate layer 150a is greater than the thickness T34 of the intermediate layer 150b. In addition, the lattice constant difference between the interposer layer 150b and the first window layer 140 (or the second window layer 141) is smaller than the lattice constant difference between the interposer layer 150a and the first window layer 140 (or the second window layer 141), so as to further reduce the lattice constant difference between the interposer layer and the second window layer 141.
In some embodiments, the interposer includes more than three connected interposer layers, and the interposer layers farther from the second type cladding layer 130 have smaller thicknesses. In addition, the farther the interlayer is from the second type cladding layer 130, the smaller the difference in lattice constant between the interlayer and the first window layer 140 (or the second window layer 141). In some embodiments, the material of the intermediate layers 150a and 150b may be (Al) x Ga 1-x ) 1-y In y P and the elemental ratio of the interposer layer 150a is different from the elemental ratio of the interposer layer 150b. In some embodiments, the material of the intermediate sub-layers 150a and 150b may be SiC, alN, gaN, znO, beSe, mgS, beTeGaAs, alAs, inP, mgSe, cdSe, or ZnTe, and the materials of the intermediate layer 150a and the intermediate layer 150b may be the same or different.
The micro light-emitting device 100C shown in fig. 2B is similar to the micro light-emitting device 100 shown in fig. 1B, except that: as shown in fig. 2B, the first interposer includes a connected interposer layer 151a and an interposer layer 151B, and the second interposer includes a connected interposer layer 152a and an interposer layer 152B.
For example, in any interlayer, the interlayer farther from the second type cladding layer 130 has a smaller thickness, and the difference in lattice constant between the interlayer farther from the second type cladding layer 130 and the first window layer 140 (or the second window layer 141) is smaller. In addition, the material of the interlayer of the two connected layers can be (Al) x Ga 1-x ) 1-y In y P, and the element proportion of the two connected intermediate layers is different, or the materials of the two connected intermediate layers can be SiC, alN, gaN, znO, beSe, mgS, beTe, gaAs, alAs, inP, mgSe, cdSe, or ZnTe, and the materials of the two connected intermediate layers can be the same or different.
In some embodiments, the number of interposers may be multiple layers, may be separate from each other, wherein at least one of the multiple interposers is a single layer structure and at least another one of the multiple interposers may include more than two interposer layers, or each interposer layer may include more than two interposer layers.
The micro light-emitting device 100D shown in fig. 3A is similar to the micro light-emitting device 100 shown in fig. 1A, except that: as shown in fig. 3A, the micro light emitting device 100D further includes a buffer layer 160, and the material may be Al 0.5 In 0.5 And (P). The buffer layer 160 is located between the second type cladding layer 130 and the first window layer 140, and the buffer layer 160 and the interposer 150 are located on two opposite sides of the first window layer 140. On the other hand, the second-type electrode 102 passes through the buffer layer 160 and is inserted into the first window layer 140 to electrically connect to the first window layer 140.
The micro light-emitting device 100E shown in fig. 3B is similar to the micro light-emitting device 100A shown in fig. 1B, except that: as shown in fig. 3B, micro-luminescenceThe element 100E further includes a buffer layer 160, and the material may be Al 0.5 In 0.5 And (P). The buffer layer 160 is located between the second type cladding layer 130 and the first window layer 140, and the buffer layer 160 and the first interposer 151 are located on two opposite sides of the first window layer 140. On the other hand, the second-type electrode 102 passes through the buffer layer 160 and is inserted into the first window layer 140 to electrically connect to the first window layer 140.
In other embodiments similar to the micro light emitting device 100E, the second type electrode 102 may further pass through the first interposer 151 and be inserted into the second window layer 141 to electrically connect to the second window layer 141. Since the second-type electrode 102 is electrically connected to the second window layer 141 with a smaller defect density of the dislocation, it is beneficial to diffuse the current to improve the distribution uniformity of the current outside the ohm contact region.
The micro light-emitting device 100F shown in fig. 3C is similar to the micro light-emitting device 100B shown in fig. 2A, except that: as shown in FIG. 3C, the micro light-emitting device 100F further includes a buffer layer 160, and the material may be Al 0.5 In 0.5 And P. The buffer layer 160 is located between the second type cladding layer 130 and the first window layer 140, and the buffer layer 160 and the interposer 150 are located on two opposite sides of the first window layer 140. On the other hand, the second type electrode 102 passes through the buffer layer 160 and is inserted into the first window layer 140 to electrically connect the first window layer 140.
The micro light-emitting device 100G shown in fig. 3D is similar to the micro light-emitting device 100C shown in fig. 2B, except that: as shown in fig. 3D, the micro light emitting device 100G further includes a buffer layer 160, and the material may be (Al) m Ga 1-m ) 1-n In n P,1 is not less than m is not less than 0 and 1>n>0. The buffer layer 160 is located between the second type cladding layer 130 and the first window layer 140, and the buffer layer 160 and the first interposer 151 are located on two opposite sides of the first window layer 140. On the other hand, the second type electrode 102 passes through the buffer layer 160 and is inserted into the first window layer 140 to electrically connect the first window layer 140.
The micro light-emitting device 100H shown in fig. 4A is similar to the micro light-emitting device 100 shown in fig. 1A, except that: as shown in fig. 4A, the second type electrode 102 passes through the interposer 150 and is inserted into the second window layer 141 to electrically connect the second window layer 141, which helps the current flow and distribution in the second window layer 141 with relatively low dislocation density before entering the first window layer 140.
In other embodiments similar to the micro light emitting device 100H, the second type electrode 102 may further pass through the intermediate sub-layers 150a and 150b and be inserted into the second window layer 141 to electrically connect to the second window layer 141. Since the second-type electrode 102 is electrically connected to the second window layer 141 with a smaller defect density of the dislocation, it is beneficial to diffuse the current to improve the distribution uniformity of the current outside the ohm contact region.
The micro light-emitting device 100I shown in fig. 4B is similar to the micro light-emitting device 100A shown in fig. 1B, except that: as shown in fig. 4B, the second type electrode 102 penetrates through the first intermediate layer 151 and inserts into the second window layer 141 to electrically connect to the second window layer 141, which helps the current to be distributed in the second window layer 141 with relatively low dislocation defect density before entering the first window layer 140. In an embodiment not shown, the second type electrode 102 may further pass through the second window layer 141 and the second interposer 152, and be inserted into the third window layer 142 to electrically connect the third window layer 142, which is helpful for current distribution in the third window layer 142 with relatively low defect density in the dislocation, then enter the second window layer 141, and then enter the first window layer 140.
In an embodiment not shown, the number of window layers may be four or more, and accordingly, the number of interposer layers may be three or more, and separated from each other for separating four or more window layers. For example, the thickness of the window layer farther from the second type cladding layer 130 is larger, or the thickness of the window layer farthest from the second type cladding layer 130 is the largest. In addition, the farther the second type cladding layer 130 is from the interposer, the smaller the thickness is.
The micro light-emitting device 100J shown in fig. 5 is similar to the micro light-emitting device 100A shown in fig. 1B, except that: as shown in fig. 5, the micro light-emitting device 100J further includes a plurality of spacer layers 144 disposed between the first interposer 151 and the second interposer 152, and the plurality of spacer layers 144 are alternately arranged between the first interposer 151, the plurality of third interposers 153, and the second interposer 152.
The first interposer 151, the plurality of third interposers 153, the second interposer 152, and the plurality of spacer layers 144 constitute a stacked structure, the first interposer 151 is separated from one third interposer 153 closest to the first interposer 151 by one spacer layer 144, adjacent two third interposers 153 are separated from each other by one spacer layer 144, and one third interposer 153 closest to the second interposer 152 is separated from the second interposer 152 by one spacer layer 144.
In this stacked structure, the ratio of the thickness of any interlayer 144 to the thickness of the first interposer 151, the second interposer 152, or the third interposer 153 is greater than or equal to 0.1 times and less than or equal to 10 times, for example, 3 times. For example, the material of the spacer layer 144 can be the same as the material of the window layer, such as GaP, but not limited thereto. In other embodiments similar to the micro light emitting device 100J, the second type electrode 102 may further penetrate through the stacked structure and insert into the second window layer 141 to electrically connect to the second window layer 141. Since the second type electrode 102 is electrically connected to the second window layer 141 with a smaller defect density of the dislocation, it is beneficial to diffuse the current to improve the distribution uniformity of the current outside the ohm contact area.
The micro light-emitting device 100K shown in fig. 6 is similar to the micro light-emitting device 100H shown in fig. 4A, except that: as shown in fig. 6, each of the micro light emitting devices 100K has a mesa structure 104, wherein the second type electrode 102 is located at one side of the mesa structure 104, and the second type electrode 102 is electrically connected to the second window layer 141 with a smaller defect density of the dislocation, so that it is beneficial to diffuse the current to improve the distribution uniformity of the current outside the ohm contact region. In addition, an interposer 150 is located in the platform structure 104.
That is, in the micro light emitting device of the above-mentioned different embodiments, a variation of the electrical connection between the second type electrode 102 and the second window layer 141 may have the mesa structure 104, wherein the second type electrode 102 is located at one side of the mesa structure 104, and at least one interposer is located in the mesa structure 104.
Fig. 7 is a schematic cross-sectional view of an epitaxial structure of a micro light-emitting device according to an embodiment of the invention. Referring to fig. 7, the micro light emitting device epitaxial structure 10 includes a substrate 11 and an epitaxial structure 1001 on the substrate 11, wherein the substrate 11 may be a gaas substrate, and the epitaxial structure 1001 includes a contact layer 103, a first type cladding layer 110, a light emitting layer 120, a second type cladding layer 130, a first window layer 140, an interposer 150, and a second window layer 141 stacked in sequence from bottom to top. The micro light emitting device of the above-mentioned different embodiments can be fabricated on the basis of the epitaxial structure 1001 or by a variation of the epitaxial structure 1001, and the epitaxial quality of the epitaxial structure 10 of the micro light emitting device is improved due to the reduced defect density of dislocations in the window layer.
In summary, in the micro light emitting device and the epitaxial structure thereof of the present invention, any two adjacent window layers are separated by an intermediate layer to block dislocation defects formed in the lower window layer due to the mismatch between the lattice constant of the lower window layer and the lattice constant of the second type cladding layer. That is, the interposer can be used to block dislocation defects from continuing to be generated from the lower window layer to the upper window layer, so as to reduce the dislocation defect density in the window layer and improve the leakage current. The leakage current is improved, which is helpful to improve the luminous efficiency of the micro light-emitting element. In addition, the defect density of dislocation in the window layer is reduced, so that the epitaxial quality of the epitaxial structure of the micro light-emitting element is improved.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (20)

1. A micro light-emitting device, comprising:
a first type cladding layer;
the luminous layer is positioned on the first type cladding layer;
the second type cladding layer is positioned on the luminous layer, and the luminous layer is positioned between the first type cladding layer and the second type cladding layer;
a multi-layer window layer located on the second type cladding layer; and
at least one interposer layer positioned between two adjacent window layers,
wherein the ion doping concentration of the at least one interposer is less than or equal to the ion doping concentration of the multi-layer window layer.
2. The micro light-emitting device as claimed in claim 1, comprising a first window layer closest to the second type cladding layer and a second window layer relatively far away from the second type cladding layer, wherein the first window layer has a lower ion doping concentration than the second window layer.
3. The micro light-emitting device of claim 1, wherein the multi-layer window layer is composed of the same material, which contains GaP or InP.
4. The micro light-emitting device of claim 1, wherein the material of the at least one interposer comprises (Al) x Ga 1-x ) 1-y In y P,1 is not less than x not less than 0 and 1>y>0。
5. The micro-light emitting device of claim 1, wherein the difference in lattice constant between the at least one interposer and the multi-layer window layer is greater than the difference in lattice constant between the second type cladding layer and the multi-layer window layer.
6. The micro light-emitting device of claim 1, wherein the material of the multi-layered window layer has a first lattice constant, and the material of the at least one interposer has a second lattice constant, wherein a ratio of the second lattice constant to the first lattice constant is greater than or equal to 1.01 times or less than or equal to 0.99 times.
7. The micro light-emitting device of claim 1, wherein the at least one interposer has a thickness of 100 nm or less.
8. A micro-light emitting device as claimed in claim 1, comprising at least a first window layer closest to the second type cladding layer and a second window layer relatively far away from the second type cladding layer, wherein the thickness of the second window layer is greater than that of the first window layer.
9. A micro-light emitting device as claimed in claim 1, wherein the defect density of the dislocations in the one of the window layers closest to the second type cladding layer is greater than the defect density of the dislocations in the remaining multi-layer window layers.
10. The micro light-emitting device of claim 1, wherein the at least one interposer comprises two connected interposers, and the interposers have different element ratios.
11. A micro-light-emitting device as claimed in claim 10, wherein the difference in lattice constant between the multi-layer window layer and one of the two connected intermediate layers, which is further from the second type cladding layer, is smaller than the difference in lattice constant between the multi-layer window layer and the other intermediate layer, which is closer to the second type cladding layer.
12. The micro light-emitting device of claim 1, further comprising a first window layer closest to the second type cladding layer and a second window layer relatively far from the second type cladding layer, and a plurality of spacer layers between the first window layer and the second window layer, wherein the number of the at least one spacer layer is a plurality of layers, and the plurality of spacer layers alternately arranged between the plurality of spacer layers form a stacked structure in which a ratio of a thickness of any one of the plurality of spacer layers to a thickness of any one of the plurality of spacer layers is greater than or equal to 0.1 times and less than or equal to 10 times.
13. The micro light-emitting device as claimed in claim 1, further comprising a first window layer closest to the second type cladding layer and a second window layer relatively far away from the second type cladding layer, a first type electrode electrically connected to the first type cladding layer and a second type electrode electrically connected to the second type cladding layer, wherein the second type electrode penetrates through the first type cladding layer, the light-emitting layer, the second type cladding layer, the first window layer and the at least one intermediate layer and is electrically connected to the second window layer.
14. The micro light-emitting device as claimed in claim 1, wherein the at least one interposer is multi-layered, and the multi-layered interposer is respectively disposed between any two adjacent window layers.
15. A micro light-emitting device, comprising:
a first type cladding layer;
the luminous layer is positioned on the first type cladding layer;
the second type cladding layer is positioned on the luminous layer, and the luminous layer is positioned between the first type cladding layer and the second type cladding layer;
the multi-layer window layer is positioned on the second type cladding layer, and the material of the multi-layer window layer has a first lattice constant; and
at least one interposer layer located between two adjacent window layers, the at least one interposer layer being made of a material having a second lattice constant,
wherein a ratio of the second lattice constant to the first lattice constant is 1.01 times or more or 0.99 times or less.
16. A micro-light-emitting element according to claim 15, wherein the multi-layer window layer is composed of the same material, which comprises gallium phosphide or indium phosphide.
17. The micro light-emitting device of claim 15, wherein the material of the at least one interposer comprises (Al) x Ga 1-x ) 1-y In y P,1 is not less than x is not less than 0 and 1>y>0。
18. The micro light-emitting device of claim 15, wherein the at least one interposer has a thickness of 100 nm or less.
19. The micro light-emitting device as claimed in claim 15, further comprising a first window layer closest to the second type cladding layer and a second window layer relatively far away from the second type cladding layer, a first type electrode electrically connected to the first type cladding layer and a second type electrode electrically connected to the second type cladding layer, wherein the second type electrode penetrates the first type cladding layer, the light-emitting layer, the second type cladding layer, the first window layer and the at least one intermediate layer and is electrically connected to the second window layer.
20. A micro-light emitting device as claimed in claim 15, wherein the defect density of the dislocations in the one of the window layers closest to the second type cladding layer is greater than the defect density of the dislocations in the remaining multi-layer window layers.
CN202211137921.3A 2022-09-19 2022-09-19 Micro light-emitting device Pending CN115411159A (en)

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