Vertically stacked LED chips, fabrication method, apparatus, and fabrication method thereof

Abstract

The application provides a vertically stacked LED chip, comprising: a first P electrode and a first N electrode; a first epitaxial light-emitting structure; the first P electrode and the first N electrode are formed on the first epitaxial light-emitting structure; a growth substrate; a second epitaxial light-emitting structure; formed on the growth substrate; a second P electrode and a second N electrode are formed on the second epitaxial light-emitting structure; a first mirror layer; formed on the second epitaxial light-emitting layer; a first bonding layer; formed on the first mirror layer; wherein the first epitaxial light-emitting structure is bonded on the first bonding layer; a passivation layer; covering the surface and side surface of the first epitaxial light-emitting structure and the second epitaxial light-emitting structure, the surface and side wall of the first bonding layer and the side wall of the first mirror layer. The technical scheme solves the problems of how to realize one pixel covering multiple colors in the chip structure, one pixel covering two basic colors, and how to independently process each pixel in the LED chip.

Description

Technical Field

[0001] This invention relates to the field of LED chips, and more particularly to a vertically stacked LED chip, a manufacturing method, an apparatus, and the manufacturing method thereof. Background Technology

[0002] Many research groups and companies are interested in microLEDs because they are suitable for next-generation displays such as smart glasses and head-mounted displays (HMDs). Compared to traditional display light sources such as organic LEDs (OLEDs) or liquid crystal displays (LCDs), inorganic LEDs offer advantages such as low power consumption, high brightness, short response time, and long lifespan. While inorganic LEDs have many advantages, achieving a high-resolution micro (RGB) color controllable light source from a single chip remains challenging. Numerous studies have been reported on microLEDs for applications in optical communications or displays, but the developed LEDs have been limited to a single color light source. Epitaxially grown inorganic LED structures emit only monochromatic light, requiring the fabrication of red, green, and blue LEDs to be arranged separately for full-color emission. Furthermore, currently, only laterally aligned RGB LED chips are used; however, the lateral arrangement of red, green, and blue LED chips requires three times the space, necessitating reduction in chip size and integration technology. Therefore, an innovative solution is needed to achieve high-resolution full-color microLED displays. Many epitaxial structures and fabrication methods have been proposed to achieve the emission of various colors from a single-pixel LED.

[0003] Some research groups have introduced InGaN / GaN nanorods or micro pyramid-shaped LED structures and demonstrated the emission of blue to red light by changing the current injection density.

[0004] One notable development is that the color of the emitted light can be varied from epitaxially grown wafers with nanostructures or microstructures. However, these nanostructures or microstructures require complex growth techniques and are subject to unavoidable external variations, making them difficult to use in industrial applications.

[0005] As an alternative approach, some research groups have achieved various emitted colors from a single pixel location by vertically stacking RGB LED chips. While this structure can cover the full color within a single pixel, it is not easily applied to displays due to the difficulty in processing each pixel individually. For color-tunable pixel LEDs, careful consideration must be given to the metallization, wiring, and connection of the driving circuitry.

[0006] Therefore, developing an LED chip that can independently process many green and blue sub-pixels and is suitable for displays with high resolution has become a key technical issue that needs to be addressed by those skilled in the art. Summary of the Invention

[0007] This invention provides a vertically stacked LED chip, a manufacturing method, an apparatus, and the manufacturing method thereof, to solve the problems of how to make one pixel in the chip structure cover two basic colors and how to independently process each pixel in the LED chip.

[0008] According to a first aspect of the present invention, a vertically stacked LED chip is provided, comprising:

[0009] First P electrode and first N electrode;

[0010] A first epitaxial light-emitting structure; the first P electrode and the first N electrode are formed on the first epitaxial light-emitting structure;

[0011] Growth substrate;

[0012] A second epitaxial light-emitting structure is formed on the growth substrate; a second P electrode and a second N electrode are formed on the second epitaxial light-emitting structure;

[0013] The first reflective mirror layer is formed on the second epitaxial light-emitting layer and is located in the region between the second P electrode and the second N electrode.

[0014] A first adhesive layer is formed on the first reflective mirror layer; wherein the first epitaxial light-emitting structure is bonded to the first adhesive layer; wherein the size of the first epitaxial light-emitting structure is adapted to the first adhesive layer.

[0015] A passivation layer covers the surface and sidewalls of the first epitaxial light-emitting structure and the second epitaxial light-emitting structure, the surface and sidewalls of the first adhesive layer, and the sidewalls of the first reflective mirror layer.

[0016] The first reflective mirror layer is used to reflect the light beam emitted by the first epitaxial light-emitting structure and to transmit the light beam emitted by the second epitaxial light-emitting structure.

[0017] The first N electrode and the second N electrode constitute the N-type electrode of the vertically stacked LED chip; the first P electrode and the second P electrode constitute the P-type electrode of the vertically stacked LED chip.

[0018] Optionally, the first adhesive layer has the property of being fully transparent to the light beam emitted by the second epitaxial light-emitting structure.

[0019] Optionally, the first reflective mirror layer has the property of being fully transparent to the light beam emitted by the second epitaxial light-emitting structure; and has the property of being fully reflective to the light beam emitted by the first epitaxial light-emitting structure.

[0020] Optionally, the first epitaxial light-emitting structure and the second epitaxial light-emitting structure are respectively a blue epitaxial light-emitting layer and a green epitaxial light-emitting layer.

[0021] Optionally, the first epitaxial light-emitting structure includes: a first N-type GaN layer, a first light-emitting layer, a first P-type GaN layer, and a first current spreading layer stacked sequentially along a direction away from the growth substrate; wherein, the first N-type GaN layer includes the first step structure; wherein, the first N electrode is formed on the first step structure; the first current spreading layer is formed on a portion of the first P-type GaN layer to form a second step structure, and the first P electrode is formed on the first current spreading layer;

[0022] A first passivation layer covers the first step structure and the second step structure, and also covers the sidewall of the first light-emitting layer.

[0023] Optionally, the second epitaxial light-emitting structure includes: a second N-type GaN layer, a second light-emitting layer, a second P-type GaN layer, and a second current spreading layer stacked sequentially along a direction away from the growth substrate; wherein the second N-type GaN layer includes a third step structure; wherein the second N-electrode is formed on the third step structure; the first bonding structure and the first reflective layer are formed on a portion of the second current spreading layer to expose a portion of the second current spreading layer; the second P-electrode is formed on the exposed portion of the second current spreading layer;

[0024] The second passivation layer covers the second step structure and the sidewalls of the second light-emitting layer, the second P-type GaN layer, the second current spreading layer, and the first reflector layer, as well as the surface and sidewalls of the first bonding structure; the passivation layer includes the first passivation layer and the second passivation layer.

[0025] Optionally, the first N-type electrode and the second N-type electrode are interconnected to form the N-type electrode of the vertically stacked LED chip.

[0026] Optionally, the vertically stacked LED chips further include:

[0027] A third epitaxial light-emitting structure, a second reflective mirror layer, and a second adhesive layer are sequentially formed between the second epitaxial light-emitting structure and the growth substrate; the second epitaxial light-emitting structure is bonded to the second adhesive layer;

[0028] A third P electrode and a third N electrode are formed on the third epitaxial light-emitting structure such that the first N electrode, the second N electrode, and the third N electrode form the N-type electrode of the vertically stacked LED chip; the first P electrode, the second P electrode, and the third P electrode form the P-type electrode of the vertically stacked LED chip.

[0029] The passivation layer further includes: a third passivation layer, which covers the surface and sidewalls of the third epitaxial light-emitting structure, and covers the sidewalls of the first reflective mirror layer, as well as the surface and sidewalls of the first bonding structure;

[0030] The second reflective mirror layer is used to reflect the light beam emitted by the second epitaxial light-emitting structure and to transmit the light beam emitted by the third epitaxial light-emitting structure.

[0031] Optionally, the second reflective mirror layer has full transparency to the light beam emitted by the third epitaxial light-emitting structure; and has total reflection to the light beam emitted by the second epitaxial light-emitting structure.

[0032] Optionally, the second adhesive layer is fully transparent to the light beam emitted by the third epitaxial light-emitting structure.

[0033] Optionally, the first epitaxial light-emitting structure, the second epitaxial light-emitting structure, and the third epitaxial light-emitting structure are, in sequence, a blue epitaxial light-emitting layer, a green epitaxial light-emitting layer, and a red epitaxial light-emitting layer.

[0034] Optionally, the first N-type electrode, the second N-type electrode, and the third N-type electrode are interconnected to form the N-type electrode of the vertically stacked LED chip.

[0035] Optionally, the third epitaxial light-emitting layer includes:

[0036] A third N-type GaN layer, a third light-emitting layer, a third P-type GaN layer, and a third current-spreading layer are stacked sequentially along a direction away from the growth substrate; wherein, the third N-type GaN layer includes a fourth step structure; wherein, the third N electrode is formed on the fourth step structure;

[0037] The second reflector layer and the second bonding structure are sequentially formed on a portion of the third current spreading layer to expose a portion of the third current spreading layer; the third P electrode is formed on the exposed portion of the third current spreading layer.

[0038] The third passivation layer covers the fourth step structure, and also covers the sidewalls of the third light-emitting layer, the third P-type GaN layer, the third current spreading layer, and the second reflector layer, as well as the surface and sidewalls of the second adhesive layer.

[0039] Optionally, the first mirror layer and / or the second mirror layer are DBR mirrors.

[0040] Optionally, the first adhesive layer and / or the second adhesive layer are transparent adhesive layers.

[0041] According to a second aspect of the present invention, a method for manufacturing vertically stacked LED chips is provided, for manufacturing the vertically stacked LED chips as described in any one of the first aspects of the present invention, the method comprising:

[0042] A first epitaxial light-emitting structure, a first N-electrode, a first P-electrode, and a first passivation layer are formed; the first N-electrode and the first P-electrode are formed on the first epitaxial light-emitting structure; the first passivation layer covers the surface and sidewalls of the first epitaxial structure layer.

[0043] A first growth substrate is provided, and a second epitaxial light-emitting structure, a first reflective mirror layer, a first adhesive layer and a second passivation layer are sequentially formed on the first growth substrate, and a second N electrode and a second P electrode are formed thereon;

[0044] The first epitaxial light-emitting structure is bonded to the first adhesive layer; wherein the second N electrode and the second P electrode are formed on the second epitaxial light-emitting structure; the second passivation layer covers the surface and sidewalls of the second epitaxial structure layer, and covers the surface and sidewalls of the first adhesive layer and the sidewalls of the first reflector layer.

[0045] Optionally, forming a first N-electrode, a first P-electrode, a first epitaxial light-emitting structure, and a first passivation layer specifically includes:

[0046] An LED chip is provided; the LED chip includes: a second growth substrate and a first epitaxial light-emitting structure, a first P electrode, a first N electrode, and a first passivation layer formed on the second growth substrate; the first P electrode and the first N electrode are formed on the first epitaxial light-emitting structure, wherein the first epitaxial light-emitting structure includes: a first N-type GaN layer, a first light-emitting layer, a first P-type GaN layer, and a first current spreading layer sequentially formed on the second growth substrate; the first N-type GaN layer includes a first step structure; the first N electrode is formed on the first step structure; the first current spreading layer is formed on a portion of the first P-type GaN layer to form a second step structure; the first P electrode is formed on the first current spreading layer; the first passivation layer covers the first step structure and the second step structure, and covers the sidewalls of the first light-emitting layer;

[0047] A first temporary transfer substrate with a bonding layer formed on its surface is provided;

[0048] The second growth substrate is peeled off to expose the light-emitting surface, and the side of the first LED chip facing away from the second growth substrate is transferred to the first temporary transfer substrate to form the first N electrode, the first P electrode, the first epitaxial light-emitting structure, and the first passivation layer on the first temporary transfer substrate.

[0049] Optionally, a second epitaxial light-emitting structure, a first reflective mirror layer, a first adhesive layer, and a second passivation layer are sequentially formed on the first growth substrate, and a second N-electrode and a second P-electrode are formed thereon; and the first epitaxial light-emitting structure is bonded to the first adhesive layer; the second N-electrode and the second P-electrode are formed on the second epitaxial light-emitting structure, specifically including:

[0050] The second epitaxial light-emitting structure, the first reflective mirror layer, the first adhesive layer, and the second passivation layer are sequentially formed on the first growth substrate, and the second N electrode and the second P electrode are formed thereon.

[0051] The first epitaxial light-emitting structure is bonded to the first adhesive layer.

[0052] Optionally, after forming the second N electrode and the second P electrode, the method further includes:

[0053] The first N-type electrode and the second N-type electrode are interconnected to form the N-type electrode of the vertically stacked LED chip.

[0054] Optionally, while sequentially forming a second epitaxial light-emitting structure, a first reflective mirror layer, a first adhesive layer, and a second passivation layer on the first growth substrate, the first epitaxial light-emitting structure is bonded to the first adhesive layer; specifically including:

[0055] Forming a second epitaxial light-emitting stack; comprising: a second N-type GaN layer, a second light-emitting layer, a second P-type GaN layer and a second current spreading layer sequentially formed on the first growth substrate;

[0056] The first reflective layer and the first adhesive layer are sequentially formed on the second current spreading layer;

[0057] The first N-type GaN layer is bonded to the first adhesive layer, and the first temporary transfer substrate is removed; so as to bond the first epitaxial light-emitting structure to the first adhesive layer.

[0058] The third step structure is formed on the second N-type GaN layer, and a first P-electrode cavity is formed thereon; the first P-electrode cavity is formed on top of the second current spreading layer.

[0059] Optionally, a second N electrode and a second P electrode are formed, specifically including:

[0060] The second passivation layer is deposited on the surface of the second epitaxial light-emitting structure;

[0061] The second passivation layer in the third step structure is etched to form a first N electrode cavity; and the second passivation layer in the first P electrode cavity is etched to expose a portion of the second current spreading layer.

[0062] Metal material is deposited in the first N electrode cavity to form the second N electrode; and metal material is deposited on the surface of the second current spreading layer in the first P electrode cavity to form the second P electrode.

[0063] Optionally, the method further includes:

[0064] Provide a third growth substrate;

[0065] A third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer are sequentially formed on the third growth substrate, and a third N-electrode and a third P-electrode are formed thereon; at the same time, the second epitaxial light-emitting structure is bonded to the second adhesive layer; the third N-electrode and the third P-electrode are formed on the third epitaxial light-emitting structure.

[0066] Optionally, a third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer are sequentially formed on the third growth substrate, and a third N-electrode and a third P-electrode are formed thereon; and the second epitaxial light-emitting structure is bonded to the second adhesive layer; the third N-electrode and the third P-electrode are formed on the third epitaxial light-emitting structure, specifically including:

[0067] The third epitaxial light-emitting structure, the second reflective mirror layer, the second adhesive layer, and the third passivation layer are sequentially formed on the second growth substrate, and the third N electrode and the third P electrode are also formed thereon.

[0068] The second epitaxial light-emitting structure is bonded to the second adhesive layer.

[0069] Optionally, a third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer are sequentially formed on the third growth substrate; simultaneously, the second epitaxial light-emitting structure is bonded to the second adhesive layer, specifically including:

[0070] A third epitaxial light-emitting stack is formed, comprising: a third N-type GaN layer, a third light-emitting layer, a third P-type GaN layer, and a third current spreading layer sequentially formed on the third growth substrate;

[0071] The second reflector layer and the second adhesive layer are sequentially formed on the third current spreading layer;

[0072] A second temporary transfer substrate with a bonding layer formed on its surface is provided;

[0073] The second growth substrate is peeled off to expose the light-emitting surface, and the second epitaxial light-emitting structure is transferred to the other side of the second growth substrate away from the second growth substrate onto the second temporary transfer substrate;

[0074] The second N-type GaN layer is bonded to the second adhesive layer, and the second temporary transfer substrate is removed; so as to bond the second epitaxial light-emitting structure to the second adhesive layer.

[0075] A fourth step structure is formed in the third N-type GaN layer, and a second P-electrode cavity is formed therein; the second P-electrode cavity is formed on top of the third current spreading layer.

[0076] Optionally, a third N electrode and a third P electrode are formed, specifically including:

[0077] The third passivation layer is deposited on the surface of the third epitaxial light-emitting structure;

[0078] The third passivation layer in the fourth step structure is etched to form a second N electrode cavity; and the third passivation layer in the second P electrode cavity is etched to expose a portion of the third current extension.

[0079] Metal material is deposited in the second N electrode cavity to form the third N electrode; and metal material is deposited on the surface of the third current spreading layer exposed in the second P electrode cavity to form the third P electrode.

[0080] Optionally, after forming the second N electrode and the second P electrode, the method further includes:

[0081] The first N-type electrode, the second N-type electrode, and the third N-type electrode are interconnected to form the N-type electrodes of the vertically stacked LED chips.

[0082] According to a third aspect of the present invention, an electronic device is provided, comprising vertically stacked LED chips as described in the first aspect of the present invention.

[0083] According to a fourth aspect of the present invention, a method for manufacturing an electronic device is provided, including the method for manufacturing vertically stacked LED chips as described in the second aspect of the present invention.

[0084] This invention proposes a vertically stacked LED chip structure. A first epitaxial light-emitting structure is bonded to a second epitaxial light-emitting structure with a first reflective mirror layer formed on its surface via a first adhesive layer, thus forming a vertically stacked LED chip structure. The technical solution proposed in this invention, because it forms a vertically stacked LED chip, solves the problems of one pixel covering two basic colors and how to independently process each pixel in the LED chip. It enables one pixel in the LED chip structure to cover two basic colors and allows for individual processing of each pixel. Furthermore, compared to horizontally arranged chip structures, it can achieve higher resolution, thereby enabling high-density display when used in a display screen. Simultaneously, the technical solution proposed in this application can reduce the size of RGB packaging devices, thereby reducing production costs and facilitating manufacturing. Attached Figure Description

[0085] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0086] Figure 1 This is a schematic flowchart of a method for manufacturing vertically stacked LED chips according to an embodiment of the present invention;

[0087] Figure 2 This is a schematic diagram of the device structure at different process stages fabricated by the vertically stacked LED chip fabrication method provided in an embodiment of the present invention. Figure 1 ;

[0088] Figure 3 This is a schematic diagram of the device structure at different process stages fabricated by the vertically stacked LED chip fabrication method provided in an embodiment of the present invention. Figure 2 ;

[0089] Figure 4 This is a schematic diagram of the device structure at different process stages fabricated according to a method for manufacturing vertically stacked LED chips, provided in an embodiment of the present invention. Figure 3 ;

[0090] Figure 5 This is a schematic diagram of the device structure at different process stages fabricated according to a method for manufacturing vertically stacked LED chips, provided in an embodiment of the present invention. Figure 4 ;

[0091] Figure 6 This is a schematic diagram of the device structure at different process stages fabricated according to a method for manufacturing vertically stacked LED chips, provided in an embodiment of the present invention. Figure 5 ;

[0092] Explanation of reference numerals in the attached figures:

[0093] 101 - First growth substrate;

[0094] 102 - Second N-type GaN layer;

[0095] 103 - Second luminescent layer;

[0096] 104 - Second p-type GaN layer;

[0097] 105 - Second current extension layer;

[0098] 106 - First reflecting mirror layer;

[0099] 107 - First adhesive layer;

[0100] 108 - First N-type GaN layer;

[0101] 109 - First luminescent layer;

[0102] 110 - First P-type GaN layer;

[0103] 111 - First current extension layer;

[0104] 112 - Passivation layer;

[0105] 113 - First P electrode;

[0106] 114 - First N electrode;

[0107] 115 - Second N electrode;

[0108] 116 - Second P electrode;

[0109] 117-bonding layer;

[0110] 118 - First temporary transfer substrate;

[0111] 119 - Second growth substrate. Detailed Implementation

[0112] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0113] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0114] Many research groups and companies are interested in microLEDs because they are well-suited for next-generation displays such as smart glasses and head-mounted displays (HMDs). Compared to traditional display light sources such as organic LEDs (OLEDs) or liquid crystal displays (LCDs), inorganic LEDs offer advantages such as low power consumption, high brightness, short response time, and long lifespan. Despite these advantages, achieving a high-resolution, micro (RGB) color-controlled light source from a single chip remains challenging.

[0115] Numerous studies have been reported on micro-LEDs used in optical communications and displays, but the developed LEDs have been limited to single-color light sources. Epitaxially grown inorganic LED structures emit only monochromatic light, requiring separate arrangements of red, green, and blue LEDs for full-color emission. Currently, the most commonly used method is horizontally aligned RGB LED chips; however, the horizontal arrangement of red, green, and blue LED chips requires three times the space, and achieving high resolution with this type of LED is difficult. Therefore, chip size reduction and advanced integration technologies are needed. Thus, an innovative solution is required to achieve high-resolution full-color micro-LED displays.

[0116] Numerous epitaxial structures and fabrication methods have been proposed to achieve the emission of various colors from a single pixel of an LED. For example, as one approach, some research groups have introduced InGaN / GaN nanorods or micro-pyramid LED structures and demonstrated emission from blue to red light by varying the current injection density. One notable development is the ability to vary the emitted color from epitaxially grown wafers with nanostructures or microstructures. However, these nanostructures or microstructures require complex growth techniques and exhibit unavoidable external variations, making them difficult to use in industrial applications.

[0117] As an alternative approach, some research groups have achieved various emitted colors from a single pixel location by vertically stacking RGB LED chips. While this structure can cover the full color within a single pixel, it is not easily applied to displays due to the difficulty in processing each pixel individually. For color-tunable pixel LEDs, careful consideration must be given to the metallization, wiring, and connection of the driving circuitry.

[0118] In view of this, the inventors of this application propose a vertically stacked passive matrix micro-LED array structure. Using a passive matrix micro-LED array structure formed by vertically stacking traditional blue and green LED epitaxial layers, the four color modes of a single chip are illuminated separately through passive matrix addressing. Specifically, it can achieve: 1. Illuminating blue alone; 2. Illuminating green alone; 3. Simultaneously illuminating blue and green at different pixel positions; 4. Simultaneously illuminating blue and green at the same pixel position; Alternatively, the green epitaxial layer can be bonded to the red epitaxial layer to form single-pixel chip control for green and red, or the blue and red epitaxial layers can be bonded to form single-pixel control for blue and red chips.

[0119] As can be seen, the vertical stacked structure chip proposed in this application can solve the problems of how to achieve multiple colors with one pixel and the difficulty of processing each pixel individually; it can realize that one pixel of the LED chip structure can cover multiple colors or even full colors, and can process each pixel individually, while achieving high resolution and reducing the size of RGB packaged devices.

[0120] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0121] Please refer to Figures 1-6 According to one embodiment of the present invention, a vertically stacked LED chip is provided, comprising:

[0122] First P electrode 113 and first N electrode 114;

[0123] First epitaxial light-emitting structure; the first P electrode 113 and the first N electrode 114 are formed on the first epitaxial light-emitting structure;

[0124] Growth substrate;

[0125] A second epitaxial light-emitting structure is formed on the growth substrate; the second P electrode 116 and the second N electrode 115 are formed on the second epitaxial light-emitting structure;

[0126] The first reflective mirror layer 106 is formed on the second epitaxial light-emitting layer and is located in the region between the second P electrode 116 and the second N electrode 115.

[0127] A first adhesive layer 107 is formed on the first reflective mirror layer 106; wherein the first epitaxial light-emitting structure is bonded to the first adhesive layer 107; wherein the size of the first epitaxial light-emitting structure is adapted to the first adhesive layer 107; the light beam emitted by the light-emitting structure, and the light beam transmitted through the second epitaxial light-emitting structure.

[0128] In one embodiment, the first adhesive layer is bonded to the first reflective mirror layer using wafer bonding technology.

[0129] Passivation layer 112; covering the surface and side of the first epitaxial light-emitting structure and the second epitaxial light-emitting structure, the surface and sidewall of the first adhesive layer 107 and the sidewall of the first reflective mirror layer 106;

[0130] The first N-electrode 114 and the second N-electrode 115 constitute the N-type electrode of the vertically stacked LED chip; the first P-electrode 113 and the second P-electrode 116 constitute the P-type electrode of the vertically stacked LED chip; wherein, the first reflective mirror layer 106 is used to reflect the first epitaxial vertically stacked LED chip, the vertically stacked LED chip as shown in the image. Figure 5 As shown.

[0131] The growth substrate has a plurality of vertically stacked LED chips formed thereon, and the number of the plurality of vertically stacked LED chips is not limited.

[0132] In one embodiment, the first epitaxial light-emitting structure and the second epitaxial light-emitting structure are respectively a blue epitaxial light-emitting structure and a green epitaxial light-emitting structure;

[0133] In another embodiment, the first epitaxial light-emitting structure and the second epitaxial light-emitting structure are a green epitaxial light-emitting structure and a red epitaxial light-emitting structure, respectively;

[0134] In other embodiments, the first epitaxial light-emitting structure and the second epitaxial light-emitting structure are a blue epitaxial light-emitting structure and a red epitaxial light-emitting structure, respectively.

[0135] This invention proposes a vertically stacked LED chip structure. A first epitaxial light-emitting structure is bonded to a second epitaxial light-emitting structure with a first reflective mirror layer 106 formed on its surface via a first adhesive layer 107, thus forming a vertically stacked LED chip structure. A first P-electrode 113, a first N-electrode 114, a second P-electrode 116, and a second N-electrode 115 are formed on the first and second epitaxial light-emitting structures, respectively. Because the proposed technical solution forms a vertically stacked LED chip structure, it solves the problems of one pixel covering multiple colors and the difficulty in processing each pixel in the LED chip. It enables one pixel in the LED chip structure to cover multiple colors and allows for individual processing of each pixel. Compared to horizontally arranged chip structures, it achieves higher resolution, enabling high-density display when used in a display screen. Furthermore, the proposed technical solution reduces the size of RGB packaging devices, thereby lowering production costs and facilitating manufacturing.

[0136] In one embodiment, the first adhesive layer 107 has the property of being fully transparent to the light beam emitted by the second epitaxial light-emitting structure.

[0137] In one embodiment, the first reflective mirror layer 106 has the property of being fully transparent to the light beam emitted by the second epitaxial light-emitting structure; and has the property of being fully reflective to the light beam emitted by the first epitaxial light-emitting structure.

[0138] In one embodiment, the first epitaxial light-emitting structure includes: a first N-type GaN layer 108, a first light-emitting layer 109, a first P-type GaN layer 110, and a first current spreading layer 111 stacked sequentially along a direction away from the growth substrate; wherein, the first N-type GaN layer 108 includes a first stepped structure; wherein, the first N-electrode 114 is formed on the first stepped structure; the first current spreading layer 111 is formed on a portion of the first P-type GaN layer 110 to form a second stepped structure, and the first P-electrode 113 is formed on the first current spreading layer 111;

[0139] A first passivation layer covers the first step structure and the second step structure, and also covers the sidewall of the first light-emitting layer 109.

[0140] In one embodiment, the second epitaxial light-emitting structure includes: a second N-type GaN layer 102, a second light-emitting layer 103, a second P-type GaN layer 104, and a second current spreading layer 105 stacked sequentially along a direction away from the growth substrate; wherein the second N-type GaN layer 102 includes a third step structure; wherein the second N-electrode 115 is formed on the third step structure; the first bonding structure and the first reflector layer 106 are formed on a portion of the second current spreading layer 105 to expose a portion of the second current spreading layer 105; and the second P-electrode 116 is formed on the exposed portion of the second current spreading layer 105.

[0141] The second passivation layer covers the second step structure and the sidewalls of the second light-emitting layer 103, the second P-type GaN layer 104, the second current spreading layer 105, and the first reflector layer 106, as well as the surface and sidewalls of the first bonding structure; the passivation layer 112 includes the first passivation layer and the second passivation layer.

[0142] In one embodiment, the first N-type electrode and the second N-type electrode are interconnected to form the N-type electrode of the vertically stacked LED chip.

[0143] The technical solution proposed in this invention forms the N-type electrodes of the vertically stacked LED chips by interconnecting the first N-type electrode and the second N-type electrode, such as... Figure 6 As shown, this reduces the need for wire bonding, thus lowering the production cost of chip products.

[0144] In another embodiment, the first N-type electrode and the second N-type electrode are not interconnected, such as... Figure 5 As shown;

[0145] In one embodiment, the first epitaxial light-emitting structure, the second epitaxial light-emitting structure, and the third epitaxial light-emitting structure are, in sequence, a blue epitaxial light-emitting layer, a green epitaxial light-emitting layer, and a red epitaxial light-emitting layer.

[0146] In one embodiment, when the first epitaxial light-emitting structure and the second epitaxial light-emitting structure are respectively a blue epitaxial light-emitting structure and a green epitaxial light-emitting structure, the third epitaxial light-emitting structure is a red epitaxial light-emitting structure; in a specific embodiment, the vertically stacked LED chips further include:

[0147] A third epitaxial light-emitting structure, a second reflective mirror layer, and a second adhesive layer are sequentially formed between the second epitaxial light-emitting structure and the growth substrate; the second epitaxial light-emitting structure is bonded to the second adhesive layer;

[0148] A third P electrode and a third N electrode are formed on the third epitaxial light-emitting structure such that the first N electrode 114, the second N electrode 115, and the third N electrode form the N-type electrode of the vertically stacked LED chip; the first P electrode 113, the second P electrode 116, and the third P electrode form the P-type electrode of the vertically stacked LED chip.

[0149] The passivation layer 112 further includes: a third passivation layer, which covers the surface and sidewalls of the third epitaxial light-emitting structure, and covers the sidewalls of the first reflective mirror layer 106, as well as the surface and sidewalls of the first bonding structure;

[0150] The second reflective layer is used to reflect the light beam emitted by the second epitaxial light-emitting structure and to transmit the light beam emitted by the third epitaxial light-emitting structure; it is not shown in the figure, but the structure is similar to that of the vertically stacked LED chip with two epitaxial light-emitting structures.

[0151] In another embodiment, the first epitaxial light-emitting structure and the second epitaxial light-emitting structure are a green epitaxial light-emitting structure and a red epitaxial light-emitting structure, respectively; the third epitaxial light-emitting structure is a blue epitaxial light-emitting structure, and the blue epitaxial light-emitting structure is formed on the first epitaxial light-emitting structure; other structures are similar to the specific embodiments described above, and will not be described in detail here.

[0152] In other embodiments, the first epitaxial light-emitting structure and the second epitaxial light-emitting structure are a blue epitaxial light-emitting structure and a red epitaxial light-emitting structure, respectively; the third epitaxial light-emitting structure is a green epitaxial light-emitting structure, and the third epitaxial light-emitting structure is formed between the first epitaxial light-emitting structure and the second epitaxial light-emitting structure; other structures are similar to the specific embodiments described above, and will not be repeated here.

[0153] The technical solution proposed in this embodiment of the present invention solves the problems of one pixel covering the full color and difficulty in independently processing each pixel in the LED chip by forming vertically stacked LED chips; it realizes that one pixel of the LED chip structure can cover the full color and can process each pixel individually; and compared with the horizontally arranged chip structure, it can achieve higher resolution, thereby enabling high-density display when used in a display screen. At the same time, the technical solution proposed in this application can reduce the size of RGB packaged devices, thereby reducing production costs and making them easier to manufacture.

[0154] In one embodiment, the second reflective mirror layer has full transparency to the light beam emitted by the third epitaxial light-emitting structure; and has total reflection to the light beam emitted by the second epitaxial light-emitting structure.

[0155] In one embodiment, the second adhesive layer is fully transparent to the light beam emitted by the third epitaxial light-emitting structure.

[0156] In one embodiment, the first N-type electrode, the second N-type electrode, and the third N-type electrode are interconnected to form the N-type electrode of the vertically stacked LED chip.

[0157] In one embodiment, the third epitaxial light-emitting layer includes:

[0158] A third N-type GaN layer, a third light-emitting layer, a third P-type GaN layer, and a third current-spreading layer are stacked sequentially along a direction away from the growth substrate; wherein, the third N-type GaN layer includes a fourth step structure; wherein, the third N electrode is formed on the fourth step structure;

[0159] The second reflector layer and the second bonding structure are sequentially formed on a portion of the third current spreading layer to expose a portion of the third current spreading layer; the third P electrode is formed on the exposed portion of the third current spreading layer.

[0160] The third passivation layer covers the fourth step structure, and also covers the sidewalls of the third light-emitting layer, the third P-type GaN layer, the third current spreading layer, and the second reflector layer, as well as the surface and sidewalls of the second adhesive layer.

[0161] In one embodiment, the first mirror layer 106 and / or the second mirror layer are DBR mirrors.

[0162] In one embodiment, the first adhesive layer 107 and / or the second adhesive layer are transparent adhesive layers.

[0163] Secondly, according to an embodiment of the present invention, a method for manufacturing vertically stacked LED chips is also provided, for manufacturing the vertically stacked LED chips described in any of the foregoing embodiments of the present invention. A flowchart of the method for manufacturing vertically stacked LED chips is shown below. Figure 1 As shown; the manufacturing method includes:

[0164] S11: Forming a first epitaxial light-emitting structure, a first N-electrode 114, a first P-electrode 113, and a first passivation layer; the first N-electrode 114 and the first P-electrode 113 are formed on the first epitaxial light-emitting structure; the first passivation layer covers the surface and sidewalls of the first epitaxial structure layer;

[0165] S12: Provide a first growth substrate 101, and sequentially form a second epitaxial light-emitting structure, a first reflective mirror layer 106, a first adhesive layer 107 and a second passivation layer on the first growth substrate 101, and form a second N electrode 115 and a second P electrode 116.

[0166] S13: The first epitaxial light-emitting structure is bonded to the first adhesive layer 107; wherein the second N electrode 115 and the second P electrode 116 are formed on the second epitaxial light-emitting structure; the second passivation layer covers the surface and sidewalls of the second epitaxial structure layer, and also covers the surface and sidewalls of the first adhesive layer 107 and the sidewalls of the first reflective mirror layer 106, such as... Figure 5 As shown.

[0167] The technical solution proposed in this embodiment of the present invention solves the problems of how to achieve two basic colors per pixel in a chip structure and the difficulty in independently processing each pixel in an LED chip because it forms vertically stacked LED chips. It achieves the technical effect of one pixel covering two basic colors in an LED chip structure and can process each pixel independently. Compared with horizontally arranged chip structures, it can achieve higher resolution, thus enabling high-density display when used in a display screen. At the same time, the technical solution proposed in this application can reduce the size of RGB packaged devices, thereby reducing production costs and making it easier to manufacture.

[0168] In one embodiment, to reduce the number of wire bonding connections for the chip, after forming the second N electrode 115 and the second P electrode 116 in step S12, the method further includes:

[0169] The first N-type electrode and the second N-type electrode are interconnected to form the N-type electrode of the vertically stacked LED chip; as... Figure 6 As shown.

[0170] In one embodiment, step S11, forming a first N electrode 114, a first P electrode 113, a first epitaxial light-emitting structure, and a first passivation layer, specifically includes:

[0171] S111: Provide an LED chip; the LED chip includes: a second growth substrate 119 and a first epitaxial light-emitting structure, a first P electrode 113, a first N electrode 114, and a first passivation layer formed on the second growth substrate 119; the first P electrode 113 and the first N electrode 114 are formed on the first epitaxial light-emitting structure, wherein the first epitaxial light-emitting structure includes: a first N-type GaN layer 108, a first light-emitting layer 109, a first P-type GaN layer 110, and a first current spreading layer 111 sequentially formed on the second growth substrate 119; the first N-type GaN layer 108 includes a first step structure; the first N electrode 114 is formed on the first step structure; the first current spreading layer 111 is formed on a portion of the first P-type GaN layer 110 to form a second step structure; the first P electrode 113 is formed on the first current spreading layer 111; the first passivation layer covers the first step structure and the second step structure, and covers the sidewall of the first light-emitting layer 109; as shown Figure 2 As shown;

[0172] S112: Provide a first temporary transfer substrate 118 on which a bonding layer 117 is formed on the surface;

[0173] S113: Peel off the second growth substrate 119 to expose the light-emitting surface, and transfer the side of the first LED chip away from the second growth substrate 119 onto the first temporary transfer substrate 118 to form the first N electrode 114, the first P electrode 113, the first epitaxial light-emitting structure, and the first passivation layer on the first temporary transfer substrate 118. Figure 3 and Figure 4 As shown.

[0174] In one specific embodiment, the specific steps are not shown in the figures; in step S12, a second epitaxial light-emitting structure, a first reflective mirror layer 106, a first adhesive layer 107, and a second passivation layer are sequentially formed on the first growth substrate 101, and a second N-electrode 115 and a second P-electrode 116 are formed; and the first epitaxial light-emitting structure is bonded to the first adhesive layer 107; the second N-electrode 115 and the second P-electrode 116 are formed on the second epitaxial light-emitting structure, specifically including:

[0175] Step S121: The second epitaxial light-emitting structure, the first reflective mirror layer 106, the first adhesive layer 107, and the second passivation layer are sequentially formed on the first growth substrate 101, and the second N electrode 115 and the second P electrode 116 are formed.

[0176] Step S122: Bond the first epitaxial light-emitting structure to the first adhesive layer 107.

[0177] In another specific embodiment, in step S12, while the second epitaxial light-emitting structure, the first reflective mirror layer 106, the first adhesive layer 107, the second passivation layer, the second N electrode 115, and the second P electrode 116 are sequentially formed on the first growth substrate 101, the first epitaxial light-emitting structure is bonded to the first adhesive layer 107; the second N electrode 115 and the second P electrode 116 specifically include:

[0178] S121: Forming a second epitaxial light-emitting stack; including: a second N-type GaN layer 102, a second light-emitting layer 103, a second P-type GaN layer 104 and a second current spreading layer 105 sequentially formed on the first growth substrate 101;

[0179] S122: The first reflector layer 106 and the first adhesive layer 107 are sequentially formed on the second current spreading layer 105;

[0180] S123: Bond the first N-type GaN layer 108 to the first adhesive layer 107, and remove the first temporary transfer substrate 118; to bond the first epitaxial light-emitting structure to the first adhesive layer 107; as follows Figure 4 As shown;

[0181] S124: The third step structure is formed on the second N-type GaN layer 102, and a first P-electrode 113 cavity is formed; the first P-electrode 113 cavity is formed on the top of the second current spreading layer.

[0182] In one embodiment, step S12, forming the second N electrode 115 and the second P electrode 116, specifically includes:

[0183] S125: Deposit the second passivation layer on the surface of the second epitaxial light-emitting structure;

[0184] S126: Etch the second passivation layer in part of the third step structure to form the cavity of the first N electrode 114; and etch the second passivation layer in the cavity of the first P electrode 113 to expose part of the second current spreading layer 105.

[0185] S127: Deposit metal material in the cavity of the first N electrode 114 to form the second N electrode 115; and deposit metal material on the surface of the second current spreading layer 105 in the cavity of the first P electrode 113 to form the second P electrode 116.

[0186] When the first epitaxial light-emitting structure and the second epitaxial light-emitting structure are respectively a blue epitaxial light-emitting structure and a green epitaxial light-emitting structure, in another specific embodiment, based on the aforementioned embodiment, the method further includes:

[0187] S14: Provides a third growth substrate;

[0188] S15: A third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer are sequentially formed on the third growth substrate, and a third N electrode and a third P electrode are formed; at the same time, the second epitaxial light-emitting structure is bonded to the second adhesive layer; the third N electrode and the third P electrode are formed on the third epitaxial light-emitting structure.

[0189] The third epitaxial light-emitting structure is a red epitaxial light-emitting structure;

[0190] The technical solution proposed in this embodiment of the present invention solves the problems of one pixel covering the full color and difficulty in independently processing each pixel in the LED chip by forming vertically stacked LED chips; it realizes that one pixel of the LED chip structure can cover the full color and each pixel can be processed independently.

[0191] In one specific embodiment, step S15 involves sequentially forming a third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer on the third growth substrate, and forming a third N-electrode and a third P-electrode; and bonding the second epitaxial light-emitting structure to the second adhesive layer; the third N-electrode and the third P-electrode being formed on the third epitaxial light-emitting structure, specifically including:

[0192] Step S151: The third epitaxial light-emitting structure, the second reflective mirror layer, the second adhesive layer, and the third passivation layer are sequentially formed on the second growth substrate 119, and the third N electrode and the third P electrode are formed.

[0193] Step S152: Bond the second epitaxial light-emitting structure to the second adhesive layer.

[0194] In another embodiment, step S15 involves sequentially forming a third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer on the third growth substrate; simultaneously, the second epitaxial light-emitting structure is bonded to the second adhesive layer, specifically including:

[0195] S151: Forming a third epitaxial light-emitting stack; including: a third N-type GaN layer, a third light-emitting layer, a third P-type GaN layer and a third current spreading layer sequentially formed on the third growth substrate;

[0196] S152: The second reflector layer and the second adhesive layer are sequentially formed on the third current spreading layer;

[0197] S153: Provide a second temporary transfer substrate on which a bonding layer 117 is formed on the surface;

[0198] S154: Peel off the second growth substrate 119 to expose the light-emitting surface, and transfer the other side of the second epitaxial light-emitting structure away from the second growth substrate 119 to the second temporary transfer substrate;

[0199] S155: Bond the second N-type GaN layer 102 to the second adhesive layer and remove the second temporary transfer substrate; to bond the second epitaxial light-emitting structure to the second adhesive layer;

[0200] S156: A fourth step structure is formed in the third N-type GaN layer, and a second P-electrode 116 cavity is formed; the second P-electrode 116 cavity is formed on the top of the third current spreading layer.

[0201] In one embodiment, step S15, forming a third N electrode and a third P electrode, specifically includes:

[0202] S157: Deposit the third passivation layer on the surface of the third epitaxial light-emitting structure;

[0203] S158: Etch the third passivation layer in part of the fourth step structure to form the cavity of the second N electrode 115; and etch the third passivation layer in the cavity of the second P electrode 116 to expose part of the third current extension.

[0204] S159: Deposit a metal material in the cavity of the second N electrode 115 to form the third N electrode; and deposit a metal material on the surface of the third current spreading layer exposed in the cavity of the second P electrode 116 to form the third P electrode.

[0205] In one embodiment, after forming the second N electrode 115 and the second P electrode 116 in step S15, the method further includes:

[0206] The first N-type electrode, the second N-type electrode, and the third N-type electrode are interconnected to form the N-type electrodes of the vertically stacked LED chips.

[0207] In addition, according to one embodiment of the present invention, an electronic device is also provided, including the vertically stacked LED chips described in the foregoing embodiments of the present invention.

[0208] Finally, according to an embodiment of the present invention, a method for manufacturing an electronic device is also provided, including the method for manufacturing vertically stacked LED chips as described in the foregoing embodiments of the present invention.

[0209] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vertically stacked LED chip, characterized in that, include: First P electrode and first N electrode; First epitaxial light-emitting structure; The first epitaxial light-emitting structure includes a first current spreading layer, and the first P electrode and the first N electrode are formed on the first epitaxial light-emitting structure, wherein the first P electrode is formed on the first current spreading layer. Growth substrate; A second epitaxial light-emitting structure is formed on the growth substrate. The second epitaxial light-emitting structure includes a second current spreading layer, and a second P electrode and a second N electrode are formed on the second epitaxial light-emitting structure. The second P electrode is formed on the exposed portion of the second current spreading layer. First reflecting mirror layer; Formed on the second epitaxial light-emitting structure; and located in the region between the second P electrode and the second N electrode; First adhesive layer; It is formed on the first reflective mirror layer; wherein the first epitaxial light-emitting structure is bonded to the first adhesive layer; the size of the first epitaxial light-emitting structure is adapted to the first adhesive layer; The first adhesive layer has the property of being fully transparent to the light beam emitted by the second epitaxial light-emitting structure; The first reflective mirror layer has the property of complete transparency to the light beam emitted by the second epitaxial light-emitting structure; and has the property of total reflection to the light beam emitted by the first epitaxial light-emitting structure; A passivation layer; covering the surface and sidewalls of the first epitaxial light-emitting structure and the second epitaxial light-emitting structure, the surface and sidewalls of the first adhesive layer, and the sidewalls of the first reflective mirror layer; The first reflective mirror layer is used to reflect the light beam emitted by the first epitaxial light-emitting structure and to transmit the light beam emitted by the second epitaxial light-emitting structure. The first N electrode and the second N electrode constitute the N-type electrode of the vertically stacked LED chip; the first P electrode and the second P electrode constitute the P-type electrode of the vertically stacked LED chip.

2. The vertically stacked LED chips according to claim 1, characterized in that, The first epitaxial light-emitting structure and the second epitaxial light-emitting structure are a blue epitaxial light-emitting layer and a green epitaxial light-emitting layer, respectively.

3. The vertically stacked LED chips according to claim 2, characterized in that, The first epitaxial light-emitting structure further includes: a first N-type GaN layer, a first light-emitting layer, and a first P-type GaN layer, which are stacked sequentially between the first current spreading layer and the growth substrate and along a direction away from the growth substrate; wherein the first N-type GaN layer includes a first step structure; wherein the first N electrode is formed on the first step structure; and the first current spreading layer is formed on a portion of the first P-type GaN layer to form a second step structure. A first passivation layer covers the first step structure and the second step structure, and also covers the sidewall of the first light-emitting layer.

4. The vertically stacked LED chips according to claim 3, characterized in that, The second epitaxial light-emitting structure includes: a second N-type GaN layer, a second light-emitting layer, and a second P-type GaN layer stacked sequentially between the growth substrate and the second current spreading layer and in a direction away from the growth substrate; wherein the second N-type GaN layer includes a third step structure; wherein the second N electrode is formed on the third step structure; a first adhesive layer and a first reflector layer are formed on a portion of the second current spreading layer to expose a portion of the second current spreading layer; a second passivation layer; covering the second step structure and covering the sidewalls of the second light-emitting layer, the second P-type GaN layer, the second current spreading layer, and the first reflector layer, as well as the surface and sidewalls of the first adhesive layer; the passivation layer includes the first passivation layer and the second passivation layer.

5. The vertically stacked LED chips according to claim 4, characterized in that, The first N-electrode and the second N-electrode are interconnected to form the N-type electrode of the vertically stacked LED chip.

6. The vertically stacked LED chips according to claim 5, characterized in that, The vertically stacked LED chips also include: A third epitaxial light-emitting structure, a second reflective mirror layer, and a second adhesive layer are sequentially formed between the second epitaxial light-emitting structure and the growth substrate; the second epitaxial light-emitting structure is bonded to the second adhesive layer; A third P electrode and a third N electrode are formed on the third epitaxial light-emitting structure such that the first N electrode, the second N electrode, and the third N electrode form the N-type electrode of the vertically stacked LED chip; the first P electrode, the second P electrode, and the third P electrode form the P-type electrode of the vertically stacked LED chip. The passivation layer further includes: a third passivation layer, which covers the surface and sidewalls of the third epitaxial light-emitting structure, and covers the sidewalls of the first reflective mirror layer, as well as the surface and sidewalls of the first adhesive layer; The second reflective mirror layer is used to reflect the light beam emitted by the second epitaxial light-emitting structure and to transmit the light beam emitted by the third epitaxial light-emitting structure.

7. The vertically stacked LED chips according to claim 6, characterized in that, The second reflective mirror layer has full transparency to the light beam emitted by the third epitaxial light-emitting structure; and has total reflection to the light beam emitted by the second epitaxial light-emitting structure.

8. The vertically stacked LED chips according to claim 7, characterized in that, The second adhesive layer is fully transparent to the light beam emitted by the third epitaxial light-emitting structure.

9. The vertically stacked LED chips according to claim 8, characterized in that, The first epitaxial light-emitting structure, the second epitaxial light-emitting structure, and the third epitaxial light-emitting structure are, in sequence, a blue epitaxial light-emitting layer, a green epitaxial light-emitting layer, and a red epitaxial light-emitting layer.

10. The vertically stacked LED chips according to claim 9, characterized in that, The first N-electrode, the second N-electrode, and the third N-electrode are interconnected to form the N-type electrodes of the vertically stacked LED chips.

11. The vertically stacked LED chips according to claim 10, characterized in that, The third epitaxial light-emitting structure includes: A third N-type GaN layer, a third light-emitting layer, a third P-type GaN layer, and a third current-spreading layer are stacked sequentially along a direction away from the growth substrate; wherein, the third N-type GaN layer includes a fourth step structure; wherein, the third N electrode is formed on the fourth step structure; The second reflective layer and the second adhesive layer are sequentially formed on a portion of the third current spreading layer to expose a portion of the third current spreading layer; the third P electrode is formed on the exposed portion of the third current spreading layer. The third passivation layer covers the fourth step structure, and also covers the sidewalls of the third light-emitting layer, the third P-type GaN layer, the third current spreading layer, and the second reflector layer, as well as the surface and sidewalls of the second adhesive layer.

12. The vertically stacked LED chips according to claim 11, characterized in that, The first reflector layer and / or the second reflector layer are DBR reflectors.

13. The vertically stacked LED chips according to claim 12, characterized in that, The first adhesive layer and / or the second adhesive layer is a transparent adhesive layer.

14. A method for fabricating vertically stacked LED chips, characterized in that, The method for fabricating vertically stacked LED chips according to any one of claims 1-13 includes: A first epitaxial light-emitting structure, a first N-electrode, a first P-electrode, and a first passivation layer are formed; the first N-electrode and the first P-electrode are formed on the first epitaxial light-emitting structure; the first passivation layer covers the surface and sidewalls of the first epitaxial light-emitting structure. A first growth substrate is provided, and a second epitaxial light-emitting structure, a first reflective mirror layer, a first adhesive layer and a second passivation layer are sequentially formed on the first growth substrate, and a second N electrode and a second P electrode are formed thereon; The first epitaxial light-emitting structure is bonded to the first adhesive layer; wherein the second N electrode and the second P electrode are formed on the second epitaxial light-emitting structure; the second passivation layer covers the surface and sidewalls of the second epitaxial light-emitting structure, and also covers the surface and sidewalls of the first adhesive layer and the sidewalls of the first reflective mirror layer.

15. The method for manufacturing vertically stacked LED chips according to claim 14, characterized in that, Forming a first N-electrode, a first P-electrode, a first epitaxial light-emitting structure, and a first passivation layer, specifically including: An LED chip is provided; the LED chip includes: a second growth substrate and a first epitaxial light-emitting structure, a first P electrode, a first N electrode, and a first passivation layer formed on the second growth substrate; the first P electrode and the first N electrode are formed on the first epitaxial light-emitting structure, wherein the first epitaxial light-emitting structure includes: a first N-type GaN layer, a first light-emitting layer, a first P-type GaN layer, and a first current spreading layer sequentially formed on the second growth substrate; the first N-type GaN layer includes a first step structure; the first N electrode is formed on the first step structure; the first current spreading layer is formed on a portion of the first P-type GaN layer to form a second step structure; the first P electrode is formed on the first current spreading layer; the first passivation layer covers the first step structure and the second step structure, and covers the sidewalls of the first light-emitting layer; The first adhesive layer has the property of being fully transparent to the light beam emitted by the second epitaxial light-emitting structure; The first reflective mirror layer has the property of complete transparency to the light beam emitted by the second epitaxial light-emitting structure; and has the property of total reflection to the light beam emitted by the first epitaxial light-emitting structure; A first temporary transfer substrate with a bonding layer formed on its surface is provided; The second growth substrate is peeled off to expose the light-emitting surface, and the LED chip is transferred to the first temporary transfer substrate from the side opposite to the second growth substrate, so as to form the first N electrode, the first P electrode, the first epitaxial light-emitting structure and the first passivation layer on the first temporary transfer substrate.

16. The method for manufacturing vertically stacked LED chips according to claim 15, characterized in that, A second epitaxial light-emitting structure, a first reflective mirror layer, a first adhesive layer, and a second passivation layer are sequentially formed on the first growth substrate, and a second N electrode and a second P electrode are formed thereon; and the first epitaxial light-emitting structure is bonded to the first adhesive layer. The second N electrode and the second P electrode are formed on the second epitaxial light-emitting structure, specifically including: The second epitaxial light-emitting structure, the first reflective mirror layer, the first adhesive layer, and the second passivation layer are sequentially formed on the first growth substrate, and the second N electrode and the second P electrode are formed thereon. The first epitaxial light-emitting structure is bonded to the first adhesive layer.

17. The method for manufacturing vertically stacked LED chips according to claim 16, characterized in that, After forming the second N electrode and the second P electrode, the process also includes: The first N-electrode and the second N-electrode are interconnected to form the N-type electrode of the vertically stacked LED chip.

18. The method for manufacturing vertically stacked LED chips according to claim 17, characterized in that, A second epitaxial light-emitting structure, a first reflective mirror layer, a first adhesive layer, and a second passivation layer are sequentially formed on the first growth substrate, while the first epitaxial light-emitting structure is bonded to the first adhesive layer; specifically including: Forming a second epitaxial light-emitting stack; comprising: a second N-type GaN layer, a second light-emitting layer, a second P-type GaN layer and a second current spreading layer sequentially formed on the first growth substrate; The first reflective layer and the first adhesive layer are sequentially formed on the second current spreading layer; The first N-type GaN layer is bonded to the first adhesive layer, and the first temporary transfer substrate is removed; so as to bond the first epitaxial light-emitting structure to the first adhesive layer. A third step structure is formed on the second N-type GaN layer, and a first P-electrode cavity is formed thereon; the first P-electrode cavity is formed on the top of the second current spreading layer.

19. The method for manufacturing vertically stacked LED chips according to claim 18, characterized in that, The formation of the second N electrode and the second P electrode specifically includes: The second passivation layer is deposited on the surface of the second epitaxial light-emitting structure; The second passivation layer in the third step structure is etched to form a first N electrode cavity; and the second passivation layer in the first P electrode cavity is etched to expose a portion of the second current spreading layer. Metal material is deposited in the first N electrode cavity to form the second N electrode; and metal material is deposited on the surface of the second current spreading layer in the first P electrode cavity to form the second P electrode.

20. The method for manufacturing vertically stacked LED chips according to claim 19, characterized in that, The method also includes: Provide a third growth substrate; A third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer are sequentially formed on the third growth substrate, and a third N-electrode and a third P-electrode are formed thereon; at the same time, the second epitaxial light-emitting structure is bonded to the second adhesive layer; the third N-electrode and the third P-electrode are formed on the third epitaxial light-emitting structure.

21. The method for manufacturing vertically stacked LED chips according to claim 20, characterized in that, A third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer are sequentially formed on the third growth substrate, and a third N electrode and a third P electrode are formed thereon; and the second epitaxial light-emitting structure is bonded to the second adhesive layer. The third N electrode and the third P electrode are formed on the third epitaxial light-emitting structure, specifically including: The third epitaxial light-emitting structure, the second reflective mirror layer, the second adhesive layer, and the third passivation layer are sequentially formed on the second growth substrate, and the third N electrode and the third P electrode are also formed thereon. The second epitaxial light-emitting structure is bonded to the second adhesive layer.

22. The method for manufacturing vertically stacked LED chips according to claim 20, characterized in that, A third epitaxial light-emitting structure, a second reflective mirror layer, a second adhesive layer, and a third passivation layer are sequentially formed on the third growth substrate; simultaneously, the second epitaxial light-emitting structure is bonded to the second adhesive layer, specifically including: A third epitaxial light-emitting stack is formed, comprising: a third N-type GaN layer, a third light-emitting layer, a third P-type GaN layer, and a third current spreading layer sequentially formed on the third growth substrate; The second reflector layer and the second adhesive layer are sequentially formed on the third current spreading layer; A second temporary transfer substrate with a bonding layer formed on its surface is provided; The second growth substrate is peeled off to expose the light-emitting surface, and the second epitaxial light-emitting structure is transferred to the other side of the second growth substrate away from the second growth substrate onto the second temporary transfer substrate; The second N-type GaN layer is bonded to the second adhesive layer, and the second temporary transfer substrate is removed; so as to bond the second epitaxial light-emitting structure to the second adhesive layer. A fourth step structure is formed on the third N-type GaN layer, and a second P-electrode cavity is formed thereon; the second P-electrode cavity is formed on top of the third current spreading layer.

23. The method for manufacturing vertically stacked LED chips according to claim 22, characterized in that, The formation of the third N electrode and the third P electrode specifically includes: The third passivation layer is deposited on the surface of the third epitaxial light-emitting structure; The third passivation layer in the fourth step structure is etched to form a second N electrode cavity; and the third passivation layer in the second P electrode cavity is etched to expose a portion of the third current extension. Metal material is deposited in the second N electrode cavity to form the third N electrode; and metal material is deposited on the surface of the third current spreading layer exposed in the second P electrode cavity to form the third P electrode.

24. The method for manufacturing vertically stacked LED chips according to claim 23, characterized in that, After forming the second N electrode and the second P electrode, the process also includes: The first N-electrode, the second N-electrode, and the third N-electrode are interconnected to form the N-type electrodes of the vertically stacked LED chips.

25. An electronic device, characterized in that, Includes the vertically stacked LED chips as described in any one of claims 1-13.

26. A method for manufacturing an electronic device, characterized in that, The method of manufacturing vertically stacked LED chips as described in any one of claims 14-24.

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