LED chip

Abstract

According to the LED chip provided by the utility model, the DBR reflecting mirror is arranged between the second type semiconductor layer and the transition layer, and the DBR reflecting mirror is provided with the plurality of openings to expose part of the second surface of the epitaxial laminated layer, so that the graphical DBR reflecting mirror can be obtained; the light emitted to the second type semiconductor layer is reflected by the DBR reflector and then is emitted from one side of the first type semiconductor layer, so that a reversed polarity structure is obtained; meanwhile, through the arrangement of the opening and the transition layer, the contact between the second type semiconductor layer and the current expansion layer is not hindered while the transition of crystal lattices and / or band gaps from the DBR reflector to the current expansion layer is ensured, so that the current diffusion can be better realized, and the electrical requirement of the LED is ensured. Namely, the beneficial effects are realized at the epitaxial end, so that the LED chip has relatively high light emitting efficiency while ensuring the electrical property requirement of the LED. And the method is particularly suitable for high-power LEDs and small-size (such as Mini and Micro) LEDs.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of LED chip especially relates to a LED chip. BACKGROUND

[0002] With the rapid development of LED technology and the gradual improvement of LED light efficiency, the application of LED is more and more extensive, and people pay more and more attention to the development prospect of LED in display screen. LED chip, as the core component of LED lamp, its function is to convert electrical energy into light energy, specifically, including epitaxial sheet and N-type electrode and P-type electrode arranged on the epitaxial sheet respectively. The epitaxial sheet includes P-type semiconductor layer, N-type semiconductor layer and active layer between the N-type semiconductor layer and the P-type semiconductor layer, when current passes through the LED chip, the hole in the P-type semiconductor and the electron in the N-type semiconductor will move to the active layer, and recombine in the active layer, so that the LED chip emits light.

[0003] At present, LED semiconductor chip develops towards high power, small size (such as Mini LED, Micro LED) and high brightness. Two main aspects affecting the light efficiency of LED are internal quantum efficiency and external quantum efficiency, and the optimization direction of external quantum efficiency, i.e. light extraction efficiency, is mainly to reduce the light absorption of each epitaxial layer, increase the effective area and angle of light extraction, etc. Taking AlGaInP-based red LED as an example: because of the light absorption of GaAs substrate and other epitaxial layers and the insufficient heat dissipation, the light extraction efficiency is limited, which affects the electrical-optical conversion efficiency of the device; therefore, AlGaInP-based red LED is mostly designed at the chip end, and the reverse polarity chip structure is adopted to improve this problem. At the same time, the brightness can be improved by thinning the epitaxial stack or reducing the doping of N-type semiconductor layer, but the thinning of the doping area will cause the voltage of LED to rise, and also affect the ESD performance of LED.

[0004] Therefore, the present application provides a LED chip. UTILITY MODEL CONTENT

[0005] The utility model aims at providing a LED chip to improve the light extraction efficiency of LED chip while ensuring the electrical requirements of LED.

[0006] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0007] A LED chip, comprising:

[0008] An epitaxial stack, the epitaxial stack comprises a first type semiconductor layer, an active layer and a second type semiconductor layer, and has a first surface and a second surface opposite to each other, wherein the first surface is a light emitting surface;

[0009] a DBR mirror disposed on a second surface side of the epitaxial stack and having a plurality of openings to expose a portion of the second surface of the epitaxial stack;

[0010] a transition layer disposed on a surface of the DBR mirror and the exposed region of the second surface;

[0011] a current spreading layer disposed on a surface of the transition layer, and the transition layer is configured to achieve a transition of lattice and / or bandgap from the DBR mirror to the current spreading layer;

[0012] a substrate embedded in each of the openings to form an integral with the epitaxial stack through a conductive bonding layer.

[0013] Preferably, a bottom surface of the opening is located on the epitaxial stack, a bottom surface area of the opening is S, and a horizontal area of the epitaxial stack is A, then A / 50≤S≤A / 2.

[0014] Preferably, each of the openings is arranged in an array.

[0015] Preferably, the conductive bonding layer comprises a metal bonding layer.

[0016] Preferably, the DBR mirror comprises a plurality of groups of low refractive index material layers and high refractive index material layers alternately grown, and the low refractive index material layer and / or the high refractive index material layer comprises a non-doped semiconductor material layer.

[0017] Preferably, the opening has an inclined sidewall.

[0018] Preferably, the inclined sidewall forms an included angle with a horizontal surface of the epitaxial stack, and the included angle ranges from 5° to 90°, inclusive.

[0019] Preferably, the LED chip comprises an AlGaInP-based LED chip.

[0020] Preferably, the first type semiconductor layer comprises an N-type AlInP confinement layer, the second type semiconductor layer comprises a P-type AlInP confinement layer, and the current spreading layer comprises a P-GaP layer.

[0021] Preferably, the DBR mirror comprises a plurality of groups of AlGaAs layers and AlAs layers alternately grown, and the transition layer comprises an AlGaInP layer.

[0022] The utility model further provides a kind of LED chip manufacturing method, comprising:

[0023] S01, provides a growth substrate;

[0024] S02, forming an epitaxial layer on the surface of the growth substrate, the epitaxial layer comprising a first type semiconductor layer, an active layer and a second type semiconductor layer which are epitaxially grown in sequence;

[0025] S03, growing a DBR mirror, the DBR mirror being disposed on the surface of the epitaxial layer;

[0026] S04, performing photolithography on the DBR mirror to form a plurality of openings exposing portions of the second surface of the epitaxial layer;

[0027] S05, growing a transition layer, the transition layer being disposed on the surface of the DBR mirror and the exposed area of the second surface;

[0028] S06, growing a current spreading layer, the current spreading layer being disposed on the surface of the transition layer;

[0029] S07, providing a substrate and embedding the substrate into each of the openings to form an integrated body with the epitaxial layer through a conductive bonding layer;

[0030] S08, peeling off the growth substrate.

[0031] Preferably, the bottom surface of the openings is located on the epitaxial layer, the bottom surface area of the openings is S, and the horizontal area of the epitaxial layer is A, then A / 50≤S≤A / 2.

[0032] The LED chip provided by the utility model has the advantages that the DBR reflector is arranged between the second-type semiconductor layer and the transition layer, and the DBR reflector has a plurality of openings to expose part of the second surface of the epitaxial layer, so that a patterned DBR reflector is obtained, light emitted to the second-type semiconductor layer is reflected by the DBR reflector and then emitted from the first-type semiconductor layer, so that a reverse polarity structure is obtained; meanwhile, the second-type semiconductor layer and the current spreading layer are not hindered in contact by the arrangement of the openings and the transition layer, so that current diffusion is better achieved, and the electrical requirements of the LED are ensured. That is, the application realizes the above beneficial effects at the epitaxial end, so that the LED chip has high light emission efficiency while ensuring the electrical requirements of the LED. It is especially suitable for high-power LEDs and small-size (such as Mini, Micro) LEDs.

[0033] Secondly, by the arrangement of A / 50≤S≤A / 2, wherein the bottom area of the opening is S, and the horizontal laying area of the epitaxial layer is A, the current spreading effect is better achieved by the cooperation of the opening, the second-type semiconductor layer and the current spreading layer while ensuring that the patterned DBR reflector improves the light emission efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to the provided drawings without creative labor.

[0035] Figure 1 The structure schematic diagram of the LED chip provided by the embodiments of the utility model;

[0036] Figures 2 to 10A structure schematic diagram corresponding to the manufacturing method of the LED chip is provided in the embodiment of the present utility model.

[0037] Explanation of symbols in the drawing:

[0038] 1. Growth substrate;

[0039] 2. Epitaxial stack;

[0040] 3. DBR mirror;

[0041] 4. Transition layer;

[0042] 5. Current spreading layer;

[0043] 6. Conductive bonding layer;

[0044] 7. Substrate;

[0045] 21. First-type semiconductor layer;

[0046] 22. Active layer;

[0047] 23. Second-type semiconductor layer;

[0048] 31. Low refractive index substance layer;

[0049] 32. High refractive index substance layer;

[0050] 33. Opening. DETAILED DESCRIPTION

[0051] To make the content of the present utility model clearer, the content of the present utility model is further explained below in combination with the drawings. The present utility model is not limited to the specific embodiment. Based on the embodiment in the present utility model, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present utility model.

[0052] As shown in Figure 1 , an LED chip comprises:

[0053] An epitaxial stack 2 comprises a first-type semiconductor layer 21, an active layer 22 and a second-type semiconductor layer 23, and has opposite first and second surfaces, wherein the first surface is a light-emitting surface;

[0054] A DBR mirror 3 is arranged on the second surface side of the epitaxial stack 2, and has a plurality of openings 33 to expose part of the second surface of the epitaxial stack 2;

[0055] A transition layer 4 is arranged on the surface of the DBR mirror 3 and the exposed area of the second surface;

[0056] a current spreading layer 5 disposed on a surface of the transition layer 4, and the transition layer 4 is configured to realize a transition of a lattice and / or a band gap of the DBR mirror 3 to the current spreading layer 5;

[0057] a substrate 7 embedded in each of the openings 33 in a manner of forming an integral with the epitaxial stack 2 through a conductive bonding layer 6.

[0058] Based on the above, in an embodiment of the present application, a bottom surface of each of the openings 33 is located on the epitaxial stack 2, an area of the bottom surface of each of the openings 33 is S, and a horizontal area of the epitaxial stack 2 is A, then A / 50≤S≤A / 2.

[0059] Based on the above, in an embodiment of the present application, each of the openings 33 is arranged in an array.

[0060] Based on the above, in an embodiment of the present application, the conductive bonding layer 6 comprises a metal bonding layer.

[0061] Based on the above, in an embodiment of the present application, the DBR mirror 3 comprises a plurality of groups of low-refractive-index material layers 31 and high-refractive-index material layers 32 alternately grown, and the low-refractive-index material layers 31 and / or the high-refractive-index material layers 32 comprise non-doped semiconductor material layers.

[0062] Based on the above, in an embodiment of the present application, each of the openings 33 has an inclined sidewall.

[0063] Based on the above, in an embodiment of the present application, the inclined sidewall forms an included angle with a horizontal surface of the epitaxial stack 2, and the included angle ranges from 5° to 90°, inclusive.

[0064] Based on the above, in an embodiment of the present application, the LED chip comprises an AlGaInP-based LED chip.

[0065] Based on the above, in an embodiment of the present application, the first-type semiconductor layer 21 comprises an N-type AlInP confinement layer, the second-type semiconductor layer 23 comprises a P-type AlInP confinement layer, and the current spreading layer 5 comprises a P-GaP layer.

[0066] Based on the above, in an embodiment of the present application, the DBR mirror 3 comprises a plurality of groups of AlGaAs layers and AlAs layers alternately grown, and the transition layer 4 comprises an AlGaInP layer.

[0067] Based on the above, the substrate 7 comprises a silicon substrate 7.

[0068] The utility model embodiment further provides a kind of LED chip's manufacturing method, comprising:

[0069] S01, as Figure 2 Shown, provide a growth substrate 1;

[0070] In one embodiment of the present application, the growth substrate 1 includes a GaAs substrate.

[0071] S02, as Figure 3 Shown, epitaxial layer 2 is formed on the surface of the growth substrate 1, and the epitaxial layer 2 includes a first type semiconductor layer 21, an active layer 22 and a second type semiconductor layer 23 which are epitaxially grown in sequence.

[0072] In one embodiment of the present application, the first type semiconductor layer 21 includes an N-type AlInP confinement layer, and the second type semiconductor layer 23 includes a P-type AlInP confinement layer.

[0073] It should be noted that the manufacturing of the epitaxial layer 2 can also include sequentially manufacturing a buffer layer, an etching stop layer and a roughening layer on the surface of the growth substrate 1, and the present application does not limit this.

[0074] S03, as Figure 4 Shown, growth DBR mirror 3, and the DBR mirror 3 is arranged on the surface of the epitaxial layer 2.

[0075] In one embodiment of the present application, as Figure 5 Shown, the DBR mirror 3 includes a plurality of groups of low refractive index material layers 31 and high refractive index material layers 32 which are alternately grown, and the low refractive index material layers 31 and / or the high refractive index material layers 32 include undoped semiconductor material layers.

[0076] Based on the above, in one embodiment of the present application, the DBR mirror 3 includes a plurality of groups of AlGaAs layers and AlAs layers which are alternately grown.

[0077] S04, as Figure 6 Shown, the DBR mirror 3 is subjected to photolithography to form a plurality of openings 33 which expose part of the second surface of the epitaxial layer 2.

[0078] In one embodiment of the present application, the bottom surface of the opening 33 is located on the epitaxial layer 2, the area of the bottom surface of the opening 33 is S, the horizontal laying area of the epitaxial layer 2 is A, and A / 50≤S≤A / 2.

[0079] In one embodiment of the present application, each of the openings 33 is arranged in an array.

[0080] In one embodiment of the present application, the opening 33 has an inclined sidewall.

[0081] In one embodiment of the present application, the inclined side wall forms an angle with the horizontal surface of the epitaxial stack 2, and the angle ranges from 5° to 90°, inclusive.

[0082] S05, as shown, a transition layer 4 is grown on the surface of the DBR mirror 3 and the exposed area of the second surface; Figure 7

[0083] Based on the above, in one embodiment of the present application, the transition layer 4 includes an AlGaInP layer.

[0084] S06, as shown, a current spreading layer 5 is grown on the surface of the transition layer 4; based on the above, in one embodiment of the present application, the current spreading layer 5 includes a P-GaP layer. Figure 8

[0085] S07, as shown, a substrate 7 is provided, and the substrate 7 is embedded in each of the openings 33 by means of a conductive bonding layer 6 to form an integral body with the epitaxial stack 2. Figure 9

[0086] Based on the above, in one embodiment of the present application, the conductive bonding layer 6 includes a metal bonding layer.

[0087] Based on the above, in one embodiment of the present application, the substrate 7 includes a silicon substrate 7.

[0088] S08, as shown, the growth substrate 1 is peeled off, and finally an LED chip as shown is obtained. Figure 10 Figure 10

[0089] It should be noted that when the growth substrate 1 surface is provided with a buffer layer, a corrosion stop layer, it needs to be removed synchronously.

[0090] ​​​​​The LED chip provided by the utility model has the advantages that the DBR reflector is arranged between the second-type semiconductor layer and the transition layer, and the DBR reflector has a plurality of openings to expose part of the second surface of the epitaxial layer, so that a patterned DBR reflector is obtained, light emitted to the second-type semiconductor layer is reflected by the DBR reflector and then emitted from the first-type semiconductor layer, so that a reverse polarity structure is obtained; meanwhile, the second-type semiconductor layer and the current spreading layer are not hindered in contact by the arrangement of the openings and the transition layer, so that current spreading is better achieved, and the electrical requirements of the LED are ensured. That is, the beneficial effects described above are achieved by the epitaxial end, so that the LED chip has high light emission efficiency while ensuring the electrical requirements of the LED. It is especially suitable for high-power LEDs and small-size (such as Mini, Micro) LEDs.

[0091] Secondly, by the arrangement of A / 50≤S≤A / 2, wherein the bottom area of the opening is S, and the horizontal laying area of the epitaxial layer is A, the current spreading effect is better achieved by the cooperation of the opening, the second-type semiconductor layer and the current spreading layer while ensuring that the patterned DBR reflector improves light emission efficiency.

[0092] The utility model also provides a kind of manufacturing method of LED chip, it is while realizing the beneficial effect described above, its manufacturing process is simple, and it is beneficial to productization.

[0093] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts of each embodiment can be referred to each other.

[0094] It is also noted that the relational terms herein, such as first and second, and the like, are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a vesicle or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such vesicle or apparatus. An element proceeded by "comprises a... " does not, without more constraints, preclude the existence of additional identical elements in the vesicle or apparatus that comprises the recited element.

[0095] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An LED chip, characterized by, The LED chip comprises: an epitaxial stack comprising a first-type semiconductor layer, an active layer and a second-type semiconductor layer, and having opposite first and second surfaces, wherein the first surface is a light-emitting surface; a DBR mirror disposed on the second surface side of the epitaxial stack and having a plurality of openings to expose part of the second surface of the epitaxial stack; a transition layer disposed on the surface of the DBR mirror and the exposed area of the second surface; a current spreading layer disposed on the surface of the transition layer, and the transition layer is used to realize the transition of the lattice and / or band gap of the DBR mirror to the current spreading layer; a substrate embedded in each of the openings to form an integral body with the epitaxial stack through a conductive bonding layer.

2. The LED chip of claim 1, wherein, The bottom surface of the opening is located in the epitaxial stack, the bottom surface area of the opening is S, and the horizontal laying area of the epitaxial stack is A, then A / 50≤S≤A / 2.

3. The LED chip of claim 1, wherein, Each of the openings is arranged in an array.

4. The LED chip of claim 1, wherein, The conductive bonding layer comprises a metal bonding layer.

5. The LED chip of claim 1, wherein, The DBR mirror comprises a plurality of groups of alternately grown low-refractive-index substance layers and high-refractive-index substance layers, and the low-refractive-index substance layers and / or the high-refractive-index substance layers comprise undoped semiconductor material layers.

6. The LED chip of claim 1, wherein, The opening has an inclined sidewall.

7. The LED chip of claim 6, wherein, The inclined sidewall forms an included angle with the horizontal surface of the epitaxial stack, and the included angle ranges from 5° to 90°, inclusive.

8. The LED chip according to any one of claims 1 to 7, characterized in that, The LED chip comprises an AlGaInP-based LED chip.

9. The LED chip of claim 6, wherein, The first-type semiconductor layer comprises an N-type AlInP confinement layer, the second-type semiconductor layer comprises a P-type AlInP confinement layer, and the current spreading layer comprises a P-GaP layer.

10. The LED chip of claim 7, wherein, The DBR mirror comprises a plurality of groups of alternately grown AlGaAs layers and AlAs layers; and the transition layer comprises an AlGaInP layer.

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