A light-emitting epitaxial structure and a light-emitting diode chip

Abstract

The present invention provides a light-emitting epitaxial structure and a light-emitting diode chip. The light-emitting diode chip includes a first active layer and a second active layer transitioned through a tunneling junction; alternatively, the light-emitting diode chip includes a first active layer and a second active layer superimposed via an insulating layer. This allows the light-emitting diode chip to include more light-emitting areas, effectively improving the light output brightness of the light-emitting diode chip. Furthermore, by designing a light-emitting diode chip with more light-emitting areas, the light-emitting diode chip can exhibit mixed-color dimming performance, expanding the application range of the light-emitting diode chip.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and more particularly to a light-emitting epitaxial structure and a light-emitting diode chip. Background Art

[0002] With the development of light-emitting diode (LED) technology, LEDs are now widely used in electronics, optics, and other fields, with significant progress in lighting, display, and digital applications. Furthermore, as the application of LEDs (light-emitting diodes) gradually expands, market requirements for LED performance are also increasing. For example, the brightness of current LEDs needs to be improved. Summary of the Invention

[0003] In view of this, the present invention provides a light-emitting epitaxial structure and a light-emitting diode chip, which effectively solve the technical problems existing in the prior art and improve the light output brightness of the light-emitting diode chip.

[0004] To achieve the above objectives, the present invention provides the following technical solutions:

[0005] A light-emitting epitaxial structure, comprising:

[0006] A substrate, a first-type conductive layer, a first active layer, a tunnel junction, a second active layer, and a second-type conductive layer stacked in sequence, wherein the tunnel junction includes a bottom layer adjacent to the first-type conductive layer and having a doping opposite to that of the first-type conductive layer, and a surface layer adjacent to the second-type conductive layer and having a doping opposite to that of the second-type conductive layer;

[0007] The first active layer includes a plurality of alternating first quantum wells and first quantum barriers, and the first active layer close to the first type conductive layer is the first quantum well, and the first active layer close to the tunnel junction is the first quantum barrier, the strain of the first quantum well is a1, the strain of the first quantum barrier is a2, the strain of the tunnel junction is b, and the strain of the substrate is c, wherein a1>a2≥b>c;

[0008] The second active layer includes a plurality of alternating second quantum barriers and second quantum wells, and the second active layer close to the tunnel junction is the second quantum barrier, and the second active layer close to the second type conductive layer is the second quantum barrier, the strain of the second quantum well is d1, and the strain of the second quantum barrier is d2, wherein d1>d2≥b>c.

[0009] Optionally, the thickness of the tunnel junction is not greater than 10 nm;

[0010] Furthermore, the doping concentration of the bottom layer is greater than the doping concentration of the first type conductive layer, and the doping concentration of the surface layer is greater than the doping concentration of the second type conductive layer.

[0011] Optionally, a buffer layer is further provided between the substrate and the first type conductive layer.

[0012] Correspondingly, the present invention also provides a light-emitting diode chip, comprising the above-mentioned light-emitting epitaxial structure.

[0013] Optionally, the light emitting diode chip includes:

[0014] a back electrode located on a side of the substrate facing away from the first type conductive layer;

[0015] and a positive electrode located on a side of the second type conductive layer facing away from the substrate.

[0016] Optionally, on one side of the second-type conductive layer, the light-emitting epitaxial structure includes an electrode region exposing the first-type conductive layer;

[0017] The light emitting diode chip includes a second electrode located on a side of the second type conductive layer facing away from the substrate, and a first electrode located in the electrode region and on a side of the first type conductive layer facing away from the substrate.

[0018] Accordingly, the present invention further provides a light-emitting epitaxial structure, comprising:

[0019] A first type conductive layer, a first active layer, a second type conductive layer, an insulating layer, an auxiliary first type conductive layer, a second active layer and an auxiliary second type conductive layer stacked in sequence;

[0020] The first active layer includes a plurality of alternating first quantum wells and first quantum barriers, and the first active layer close to the first type conductive layer is the first quantum well, and the first active layer close to the second type conductive layer is the first quantum barrier;

[0021] The second active layer includes a plurality of alternating second quantum barriers and second quantum wells, and the second active layer close to the auxiliary first type conductive layer is the second quantum well, and the second active layer close to the auxiliary second type conductive layer is the second quantum barrier.

[0022] Optionally, the light-emitting epitaxial structure further includes:

[0023] an etching stop layer located on a side of the first type conductive layer facing away from the second type conductive layer;

[0024] a buffer layer located on a side of the corrosion stop layer away from the second type conductive layer;

[0025] and a temporary substrate located on a side of the buffer layer facing away from the second-type conductive layer.

[0026] Correspondingly, the present invention further provides a light-emitting diode chip, which includes the above-mentioned light-emitting epitaxial structure.

[0027] Optionally, the light emitting diode chip further includes:

[0028] a transparent conductive layer located on a side of the first-type conductive layer facing away from the second-type conductive layer, wherein the first-type conductive layer comprises a plurality of first through holes on one side thereof exposing the auxiliary first-type conductive layer, and an isolation layer is formed on sidewalls of the first through holes, and the transparent conductive layer is connected to the auxiliary first-type conductive layer through the first through holes;

[0029] an auxiliary transparent conductive layer located on a side of the auxiliary second-type conductive layer facing away from the second-type conductive layer, wherein the auxiliary second-type conductive layer comprises a plurality of second through holes exposing the second-type conductive layer on one side thereof, and an isolation layer is formed on sidewalls of the second through holes, and the auxiliary transparent conductive layer is connected to the second-type conductive layer through the second through holes;

[0030] a reflective layer located on a side of the auxiliary transparent conductive layer facing away from the second-type conductive layer;

[0031] a bonding layer located on a side of the reflective layer facing away from the second-type conductive layer;

[0032] a permanent substrate located on a side of the bonding layer facing away from the second type conductive layer;

[0033] A first electrode is located on a side of the transparent conductive layer facing away from the second type conductive layer, and a second electrode is located on a side of the permanent substrate facing away from the second type conductive layer.

[0034] Compared with the existing technology, the technical solution provided by the present invention has at least the following advantages:

[0035] The present invention provides a light-emitting epitaxial structure and a light-emitting diode chip. The light-emitting diode chip includes a first active layer and a second active layer transitioned through a tunneling junction; alternatively, the light-emitting diode chip includes a first active layer and a second active layer superimposed via an insulating layer. This allows the light-emitting diode chip to include more light-emitting areas, effectively improving the light output brightness of the light-emitting diode chip. Furthermore, by designing a light-emitting diode chip with more light-emitting areas, the light-emitting diode chip can exhibit mixed-color dimming performance, expanding the application range of the light-emitting diode chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0037] Figure 1 A schematic structural diagram of a light-emitting epitaxial structure provided by an embodiment of the present invention;

[0038] Figure 2 A schematic structural diagram of another light-emitting epitaxial structure provided by an embodiment of the present invention;

[0039] Figure 3 A schematic structural diagram of a light-emitting diode chip provided by an embodiment of the present invention;

[0040] Figure 4 A schematic structural diagram of another light-emitting diode chip provided by an embodiment of the present invention;

[0041] Figure 5 A schematic structural diagram of another light-emitting epitaxial structure provided by an embodiment of the present invention;

[0042] Figure 6 A schematic structural diagram of another light-emitting epitaxial structure provided by an embodiment of the present invention;

[0043] Figure 7 This is a schematic structural diagram of another light emitting diode chip provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] As described in the background, with the development of light-emitting diode (LED) technology, LEDs are now widely used in electronics, optics, and other fields, with significant progress in lighting, display, and digital applications. Furthermore, as the application of LEDs (light-emitting diodes) continues to expand, market requirements for LED performance are also increasing. For example, the brightness of current LEDs needs to be improved.

[0046] Based on this, embodiments of the present invention provide a light-emitting epitaxial structure and a light-emitting diode chip, which effectively solve the technical problems existing in the prior art and improve the light output brightness of the light-emitting diode chip. The light-emitting epitaxial structure and the light-emitting diode chip provided in embodiments of the present invention can be made of materials related to the GaN material system or AlGaInP quaternary materials, which are not limited to this invention.

[0047] To achieve the above purpose, the technical solution provided by the embodiment of the present invention is as follows, specifically combined with Figures 1 to 7 The technical solutions provided by the embodiments of the present invention are described in more detail.

[0048] Example 1

[0049] refer to Figure 1 FIG. 1 is a schematic structural diagram of a light-emitting epitaxial structure provided by an embodiment of the present invention, wherein the light-emitting epitaxial structure provided by an embodiment of the present invention includes:

[0050] A substrate 110, a first type conductive layer 120, a first active layer 130, a tunnel junction 140, a second active layer 150 and a second type conductive layer 160 are stacked in sequence, wherein the tunnel junction 140 includes a bottom layer close to the first type conductive layer 120 and having an opposite doping to the first type conductive layer 120, and a surface layer close to the second type conductive layer 160 and having an opposite doping to the second type conductive layer 160.

[0051] The first active layer 130 includes a plurality of alternating first quantum wells 131 and first quantum barriers 132, and the first active layer 130 close to the first type conductive layer 120 is the first quantum well 131, and the first active layer 130 close to the tunnel junction 140 is the first quantum barrier 132, the strain of the first quantum well 131 is a1, the strain of the first quantum barrier 132 is a2, the strain of the tunnel junction 140 is b, and the strain of the substrate 110 is c, wherein a1>a2≥b>c.

[0052] The second active layer 150 includes a plurality of alternating second quantum barriers 151 and second quantum wells 152, and the second active layer 150 close to the tunnel junction 140 is the second quantum barrier 151, and the second active layer 150 close to the second type conductive layer 160 is the second quantum barrier 151, the strain of the second quantum well 152 is d1, and the strain of the second quantum barrier 151 is d2, wherein d1>d2≥b>c.

[0053] The first type conductive layer provided in the embodiment of the present invention may be an N-type conductive layer, and the second type conductive layer may be a P-type conductive layer. Alternatively, the first type conductive layer provided in the embodiment of the present invention may be a P-type conductive layer, and the second type conductive layer may be an N-type conductive layer, which is not limited in the present invention.

[0054] It can be understood that the relationship between the strain a1 of the first quantum well, the strain a2 of the first quantum barrier, the strain b of the tunnel junction 140 and the strain c of the substrate provided by the embodiment of the present invention is: a1>a2≥b>c; and the relationship between the strain d1 of the second quantum well, the strain d2 of the second quantum barrier, the strain b of the tunnel junction 140 and the strain c of the substrate is d1>d2≥b>c, thereby optimizing the electronic band structure of the first active layer and the second active layer and improving the performance of the light-emitting epitaxial structure.

[0055] Furthermore, the LED chip provided by the embodiments of the present invention includes a first active layer and a second active layer transitioned through a tunneling junction, allowing the LED chip to include more light-emitting areas, effectively improving the LED chip's light output brightness. Furthermore, by designing the LED chip with more light-emitting areas, the LED chip can achieve mixed-color dimming performance, expanding the LED chip's applicability.

[0056] In one embodiment of the present invention, the thickness of the tunnel junction provided by the present invention is not greater than 10 nm; and, the doping concentration of the bottom layer of the tunnel junction provided by the embodiment of the present invention is greater than the doping concentration of the first type conductive layer, and the doping concentration of the surface layer of the tunnel junction is greater than the doping concentration of the second type conductive layer.

[0057] refer to Figure 2 As shown, it is a structural schematic diagram of another light-emitting epitaxial structure provided in an embodiment of the present invention, wherein, in the light-emitting epitaxial structure provided in an embodiment of the present invention, a buffer layer 170 is also included between the substrate 110 and the first type conductive layer 120, thereby improving the growth quality of the light-emitting epitaxial structure.

[0058] Correspondingly, an embodiment of the present invention further provides a light-emitting diode chip, comprising the light-emitting epitaxial structure provided in any one of the above-mentioned first embodiments.

[0059] In one embodiment of the present invention, the electrodes of the light-emitting diode chip provided by the present invention can be located on different sides of the light-emitting epitaxial structure. Figure 3 FIG. 1 is a schematic structural diagram of a light-emitting diode chip provided in an embodiment of the present invention, wherein the light-emitting diode chip provided in an embodiment of the present invention includes:

[0060] a back electrode 181 located on the side of the substrate 110 facing away from the first type conductive layer 120 , wherein the substrate 110 provided in the embodiment of the present invention is a conductive substrate, and a positive electrode 182 located on the side of the second type conductive layer 160 facing away from the substrate 110 .

[0061] Alternatively, the electrodes of the light-emitting diode chip provided by the embodiment of the present invention may be located on the same side of the light-emitting epitaxial structure. Figure 4 , which is a schematic structural diagram of another light-emitting diode chip provided by an embodiment of the present invention, wherein, on one side of the second-type conductive layer 160 , the light-emitting epitaxial structure includes an electrode region exposing the first-type conductive layer 120 .

[0062] The LED chip includes a second electrode 192 located on a side of the second type conductive layer 160 facing away from the substrate 110 , and a first electrode 191 located in the electrode region and on a side of the first type conductive layer 120 facing away from the substrate 110 .

[0063] Example 2

[0064] The embodiment of the present invention also provides a light-emitting epitaxial structure. Figure 5 FIG. 1 is a schematic structural diagram of another light-emitting epitaxial structure provided by an embodiment of the present invention, wherein the light-emitting epitaxial structure provided by an embodiment of the present invention includes:

[0065] The first type conductive layer 210 , the first active layer 220 , the second type conductive layer 230 , the insulating layer 240 , the auxiliary first type conductive layer 250 , the second active layer 260 and the auxiliary second type conductive layer 270 are sequentially stacked.

[0066] The first active layer 220 includes a plurality of alternating first quantum wells 221 and first quantum barriers 222 . The first active layer 220 close to the first type conductive layer 210 is the first quantum well 221 , and the first active layer 220 close to the second type conductive layer is the first quantum barrier 222 .

[0067] The second active layer 260 includes a plurality of alternating second quantum wells 261 and second quantum barriers 262 , and the second active layer 260 close to the auxiliary first type conductive layer 250 is the second quantum well 261 , and the second active layer 260 close to the auxiliary second type conductive layer 270 is the second quantum barrier 262 .

[0068] The first-type conductive layer and the auxiliary first-type conductive layer provided in the embodiment of the present invention may be N-type conductive layers, and the second-type conductive layer and the auxiliary second-type conductive layer may be P-type conductive layers. Alternatively, the first-type conductive layer and the auxiliary first-type conductive layer provided in the embodiment of the present invention may be P-type conductive layers, and the second-type conductive layer and the auxiliary second-type conductive layer may be N-type conductive layers, but the present invention is not limited to this.

[0069] As can be understood, the LED chip provided in the embodiments of the present invention includes a first active layer and a second active layer superimposed via an insulating layer, resulting in a larger light-emitting area on the LED chip, effectively improving the brightness of the LED chip. Furthermore, by designing an LED chip with more light-emitting areas, the LED chip can achieve mixed-color dimming performance, expanding the application range of the LED chip.

[0070] In one embodiment of the present invention, the light-emitting epitaxial structure provided by the present invention may be a light-emitting epitaxial structure for bonding with other substrates. Figure 6 FIG. 1 is a schematic structural diagram of another light-emitting epitaxial structure provided by an embodiment of the present invention, wherein the light-emitting epitaxial structure provided by an embodiment of the present invention further includes:

[0071] An etching stop layer 281 is located on the side of the first type conductive layer 210 away from the second type conductive layer 230; a buffer layer 282 is located on the side of the etching stop layer 281 away from the second type conductive layer 230; and a temporary substrate 283 is located on the side of the buffer layer 282 away from the second type conductive layer 230. After the auxiliary second type conductive layer of the light-emitting epitaxial structure is bonded to other substrates, the etching stop layer 281, the buffer layer 282 and the temporary substrate 283 are removed.

[0072] Correspondingly, an embodiment of the present invention further provides a light-emitting diode chip, which includes the light-emitting epitaxial structure provided in any one of the second embodiments above.

[0073] refer to Figure 7 FIG. 1 is a schematic structural diagram of another light-emitting diode chip provided in an embodiment of the present invention, wherein the light-emitting diode chip provided in an embodiment of the present invention further includes:

[0074] A transparent conductive layer 2901 is located on the side of the first-type conductive layer 210 facing away from the second-type conductive layer 230. The first-type conductive layer 210 includes a plurality of first through-holes exposing the auxiliary first-type conductive layer 250, and an isolation layer 2902 is formed on the sidewalls of the first through-holes. The transparent conductive layer 2901 is connected to the auxiliary first-type conductive layer 250 through the first through-holes. The first through-holes provided in this embodiment of the present invention are connected to a trench surrounding the light-emitting epitaxial structure, and the trench can be located at the edge of the light-emitting epitaxial structure. The transparent conductive layer 2901 provided in this embodiment of the present invention extends to the trench and connects to the auxiliary first-type conductive layer 250, that is, the transparent conductive layer 2901 wraps around the surface of the first-type conductive layer 210 and most of the side surfaces of the trench. The inclination angle of the wrapped side portions can be greater than 45 degrees and less than 90 degrees.

[0075] An auxiliary transparent conductive layer 2903 is located on the side of the auxiliary second-type conductive layer 270 away from the second-type conductive layer 230, wherein on one side of the auxiliary second-type conductive layer 270, a plurality of second through holes exposing the second-type conductive layer 230 are included, and an isolation layer 2904 is formed on the sidewalls of the second through holes, and the auxiliary transparent conductive layer 2903 is connected to the second-type conductive layer 230 through the second through holes.

[0076] A reflective layer 2905 is located on a side of the auxiliary transparent conductive layer 2903 away from the second-type conductive layer 230 .

[0077] A bonding layer 2906 is located on a side of the reflective layer 2905 facing away from the second-type conductive layer 230 .

[0078] A permanent substrate 2907 is located on the side of the bonding layer 2906 facing away from the second type conductive layer 230. The permanent substrate 2907 may be a silicon substrate.

[0079] A first electrode 2908 is located on a side of the transparent conductive layer 2901 facing away from the second type conductive layer 230 , and a second electrode 2909 is located on a side of the permanent substrate 2907 facing away from the second type conductive layer 230 .

[0080] Embodiments of the present invention provide a light-emitting epitaxial structure and a light-emitting diode chip. The light-emitting diode chip includes a first active layer and a second active layer transitioned through a tunneling junction; alternatively, the light-emitting diode chip includes a first active layer and a second active layer superimposed via an insulating layer. This allows the light-emitting diode chip to include more light-emitting areas, effectively improving the light output brightness of the light-emitting diode chip. Furthermore, by designing a light-emitting diode chip with more light-emitting areas, the light-emitting diode chip can achieve mixed-color dimming performance, expanding the application range of the light-emitting diode chip.

[0081] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A light-emitting epitaxial structure, characterized in that: include: A substrate, a first-type conductive layer, a first active layer, a tunnel junction, a second active layer, and a second-type conductive layer stacked in sequence, wherein the tunnel junction includes a bottom layer proximate to the first-type conductive layer and having a doping opposite to that of the first-type conductive layer, and a surface layer proximate to the second-type conductive layer and having a doping opposite to that of the second-type conductive layer; the doping concentration of the bottom layer is greater than the doping concentration of the first-type conductive layer, and the doping concentration of the surface layer is greater than the doping concentration of the second-type conductive layer; The first active layer includes a plurality of alternating first quantum wells and first quantum barriers, and the first active layer close to the first type conductive layer is the first quantum well, and the first active layer close to the tunnel junction is the first quantum barrier, the strain of the first quantum well is a1, the strain of the first quantum barrier is a2, the strain of the tunnel junction is b, and the strain of the substrate is c, wherein a1>a2≥b>c; The second active layer includes a plurality of alternating second quantum barriers and second quantum wells, and the second active layer close to the tunnel junction is the second quantum barrier, and the second active layer close to the second type conductive layer is the second quantum barrier, the strain of the second quantum well is d1, and the strain of the second quantum barrier is d2, wherein d1>d2≥b>c.

2. The light-emitting epitaxial structure according to claim 1, wherein: The thickness of the tunnel junction is no more than 10 nm.

3. The light-emitting epitaxial structure according to claim 1, wherein: A buffer layer is further included between the substrate and the first type conductive layer.

4. A light-emitting diode chip, characterized in that: The light-emitting epitaxial structure comprises the light-emitting epitaxial structure according to any one of claims 1 to 3.

5. The light-emitting diode chip according to claim 4, characterized in that: The light emitting diode chip comprises: a back electrode located on a side of the substrate facing away from the first type conductive layer; and a positive electrode located on a side of the second type conductive layer facing away from the substrate.

6. The light-emitting diode chip according to claim 4, characterized in that On one side of the second-type conductive layer, the light-emitting epitaxial structure includes an electrode region exposing the first-type conductive layer; The light emitting diode chip includes a second electrode located on a side of the second type conductive layer facing away from the substrate, and a first electrode located in the electrode region and on a side of the first type conductive layer facing away from the substrate.

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