Laminated electronic device and method for manufacturing laminated electronic device

Abstract

The present invention relates to a method for manufacturing a laminated electronic device, the method including the steps of: sequentially laminating a first micro LED layer and a second micro LED layer on a substrate; and laminating a third micro LED layer on the second micro LED layer, wherein the first micro LED layer includes, in order from the bottom layer thereof, a first n-type current layer, a first current transport layer, a first p-type layer, a first active layer, and a first n-type layer, and the second micro LED layer includes, in order from the bottom layer thereof, a second n-type current layer, a second current transport layer, a second p-type layer, a second active layer, and a second n-type layer, wherein the first n-type layer and the second n-type current layer are the same layer and are electrically connected to a common electrode and a second electrode. Provided are the laminated electronic device capable of implementing a high-resolution display by laminating individual micro LEDs, and the method for manufacturing the laminated electronic device.

Description

Layered electronic devices and methods for manufacturing layered electronic devices

[0001] The present invention relates to a stacked electronic device and a method for manufacturing the same, and more particularly, to a stacked electronic device in which a plurality of micro LEDs are stacked to form a single pixel, and a method for manufacturing the same.

[0002] The most widely used display today is the LCD. However, LCD-based displays require backlighting (LED, CCFL). This structure has limitations such as large thickness, low power efficiency, and narrow viewing angles. OLED displays, an alternative, offer improved power efficiency compared to LCDs, but their use of organic materials has led to issues such as low durability and burn-in (deterioration).

[0003] MicroLEDs, which have recently attracted attention, are inorganic-based devices that significantly improve the durability issues mentioned above. Furthermore, they boast superior brightness compared to conventional OLEDs, and like OLEDs, unused elements can be turned off, enabling them to display perfect black. In other words, microLED displays are a technology that maintains the advantages of OLED displays while addressing their shortcomings.

[0004] Typically, a microLED display implements one pixel by including sub-pixels consisting of a red microLED, a green microLED, and a blue microLED.

[0005] In this regard, Patent Publication No. 10-2022-0133387 discloses a 'micro LED display' that implements one pixel by horizontally arranging red, green, and blue micro LEDs.

[0006] However, since arranging individual LEDs horizontally utilizes a large horizontal space, there is a clear limitation in manufacturing high-resolution displays.

[0007] [Prior Art Literature]

[0008] [Patent Document]

[0009] (Patent Document 1) Patent Publication No. 10-2022-0133387

[0010] In order to solve the above-described problems, the present invention aims to provide a laminated electronic device capable of implementing a high-resolution display by laminating individual micro LEDs and a method for manufacturing the laminated electronic device.

[0011] In order to achieve the above-described object, a stacked electronic device according to an embodiment of the present invention is a stacked electronic device formed by stacking a plurality of micro LEDs, comprising: a first micro LED; a second micro LED, at least a portion of which is positioned on an upper layer of the first micro LED; a third micro LED positioned on the first micro LED and the second micro LED; a common electrode electrically connected to the first micro LED, the second micro LED, and the third micro LED; a first electrode electrically connected to the first micro LED; a second electrode electrically connected to the second micro LED; and a third electrode electrically connected to the third micro LED; wherein the first micro LED to the third micro LED each include an active layer, a p-type layer positioned below the active layer, and an n-type layer positioned above the active layer; and at least one of the first micro LED to the third micro LED includes a current conducting layer positioned below the p-type layer; And it may further include an n-type current layer located below the current conducting layer.

[0012] Additionally, in an embodiment of the present invention, the third micro LED may be a red micro LED.

[0013] In addition, in the laminated electronic device according to an embodiment of the present invention, when power is applied to the first electrode, the first microLED corresponding to the first region can emit light, when power is applied to the second electrode, the second microLED corresponding to the second region can emit light, and when power is applied to the third electrode, the third microLED corresponding to the first region and the second region can emit light.

[0014] In addition, in an embodiment of the present invention, the n-type layer of the first microLED is in contact with the common electrode, the n-type current layer of the second microLED is in contact with the second electrode, and the n-type layer of the first microLED and the n-type current layer of the second microLED may be the same layer.

[0015] Meanwhile, a method for manufacturing a stacked electronic device according to an embodiment of the present invention comprises the steps of: sequentially stacking a first micro LED layer (100') and a second micro LED layer on a substrate; sequentially stacking a third micro LED layer on the second micro LED layer; the first micro LED layer (100') includes, in order from the bottom, a first n-type current layer, a first current transfer layer, a first p-type layer, a first active layer, and a first n-type layer; the second micro LED layer includes, in order from the bottom, a second n-type current layer, a second current transfer layer, a second p-type layer, a second active layer, and a second n-type layer; and the first n-type layer and the second n-type current layer are the same layer and can be electrically connected to a common electrode and a second electrode.

[0016] Stacked electronic devices can provide screens with high resolution and high luminous efficiency by stacking individual LEDs to implement a single pixel.

[0017] FIG. 1 is a drawing showing a cross-sectional shape of a laminated electronic device according to an embodiment of the present invention.

[0018] Figure 2 is a drawing showing a state in which the first microLED emits light in an embodiment of the present invention.

[0019] Figure 3 is a drawing showing a state in which a second microLED emits light in an embodiment of the present invention.

[0020] Figure 4 is a drawing showing a state in which the third micro LED emits light in an embodiment of the present invention.

[0021] FIGS. 5A to 5F and FIGS. 6A to 6E are drawings showing a method for manufacturing a layered electronic device according to an embodiment of the present invention.

[0022] Those skilled in the art will be able to develop various devices that embody the principles of the invention and fall within the scope and spirit of the invention, even if not explicitly described or illustrated in this specification. Furthermore, all conditional terms and embodiments listed herein are expressly intended, in principle, to facilitate understanding of the invention's concept and should be understood as being in no way limiting to the specifically listed embodiments and conditions.

[0023] The above-described objects, features and advantages will become more apparent through the description of the invention with reference to the attached drawings, so that a person skilled in the art will be able to easily implement the technical idea of ​​the invention.

[0024] The embodiments described herein will be described with reference to ideal drawings of the present invention. The form of the illustrated drawings may vary depending on manufacturing techniques and / or tolerances. Therefore, the embodiments of the present invention are not limited to the specific forms illustrated, but also encompass variations in form resulting from the manufacturing process.

[0025] When describing various embodiments, components that perform the same function will be given the same names and reference numbers for convenience even if the embodiments are different. In addition, the expressions ‘on’ and ‘on top of’ do not only mean direct contact, but can also be interpreted to include cases where other layers are involved in the middle. In addition, the meaning of ‘penetrates A’ does not only mean penetrating the entirety of A, but also includes cases where some layers of A are penetrated. In addition, ‘electrically connected’ between an electrode and A does not only mean direct contact between the electrode and A, but also includes cases where a conductive material is placed between the electrode and A and the electrode and A are indirectly connected. Furthermore, for convenience, the configuration and operation already described in other embodiments will be omitted.

[0026] Hereinafter, the structure of a laminated electronic device (hereinafter, “laminated electronic device”) according to an embodiment of the present invention will be examined.

[0027] FIG. 1 is a drawing showing a cross-sectional shape of a laminated electronic device (1) according to an embodiment of the present invention.

[0028] Referring to FIG. 1, a stacked electronic device (1) may be formed by stacking a plurality of micro LEDs. The stacked electronic device (1) may include a first micro LED (100); a second micro LED (200) at least a portion of which is positioned on an upper layer of the first micro LED (100); a third micro LED (300) positioned on the first micro LED (100) and the second micro LED (200); a common electrode (700) electrically connected to the first micro LED (100), the second micro LED (200), and the third micro LED (300); a first electrode (400) electrically connected to the first micro LED (100); a second electrode (500) electrically connected to the second micro LED (200); and a third electrode (600) electrically connected to the third micro LED (300).

[0029] Here, the first micro LED (100) to the third micro LED (300) may each include an active layer, a p-type layer positioned below the active layer, and an n-type layer positioned above the active layer. At least one of the first micro LED (100) to the third micro LED (300) may further include a current transfer layer positioned below the p-type layer; and an n-type current layer positioned below the current transfer layer.

[0030] The stacked electronic device (1) may include a plurality of microLEDs. The microLEDs may be one of a first microLED (100), a second microLED (200), and a third microLED (300). The plurality of microLEDs may include the first microLED (100) to the third microLED (300), and in this case, each microLED may implement a different color.

[0031] The substrate (10) can be used as a growth substrate for growing microLEDs. The substrate (10) can support the stacked electronic device (1) and / or microLEDs, and can be separated from the microLEDs during the manufacturing stage.

[0032] The microLED may have a horizontal length and a vertical length of 100 micrometers or less. The microLED may include a p-type layer, an active layer, and an n-type layer. The active layer may be provided between the p-type layer and the n-type layer. The p-type layer may be a p-type semiconductor, and the n-type layer may be an n-type semiconductor. The p-type layer may be a p-type cladding layer made of a p-type semiconductor, and the n-type layer may be an n-type cladding layer made of an n-type semiconductor.

[0033] The color of light emitted by a microLED can be determined by the material and / or properties of the p-type and n-type layers. That is, the microLED can emit light of a wavelength corresponding to the energy band gap in the pn junction region.

[0034] The active layer can emit light by injecting electrons and holes and combining with each other, and can be formed into a single quantum well (SQW) or multiple quantum well (MQW) structure. However, the active layer is not limited to the above-described configuration.

[0035] A stacked electronic device (1) may include a first micro LED (100), a second micro LED (200), and a third micro LED (300). The first micro LED (100) may be formed of a red LED, a green LED, or a blue LED. The second micro LED (200) may be formed of a red LED, a green LED, or a blue LED. The third micro LED (300) may be formed of a red LED, a green LED, or a blue LED.

[0036] In the stacked electronic device (1), the first microLED (100) to the third microLED (300) may be configured to emit different colors, respectively. In the microLED, the n-type layer and the p-type layer may each be formed of at least one of GaAs, GaP, GaAsP, and GaN.

[0037] If the first microLED (100) is a blue LED, the n-type layer and the p-type layer may be made of GaN. If the second microLED (200) is a green LED, the n-type layer and the p-type layer may be made of GaN. If the third microLED (300) is a red LED, the n-type layer and the p-type layer may be made of GaAs and GaP, respectively. However, the materials of the n-type layer and the p-type layer of the microLED are not limited to those described above.

[0038] The laminated electronic device (1) may further include a common electrode (700), a first electrode (400), a second electrode (500), and a third electrode (600).

[0039] The common electrode (700) can be electrically connected to the first micro LED (100), the second micro LED (200), and the third micro LED (300). That is, the common electrode (700) can receive a negative voltage or a positive voltage and commonly receive current from a plurality of micro LEDs or provide current to a plurality of micro LEDs.

[0040] Since the common electrode (700) must be connected to all micro LEDs, it may be provided to extend from the upper surface to the inside of the stacked electronic device (1). The common electrode (700) may extend deeper than the entire layer of the third micro LED (300), may extend deeper than the entire layer or part of the layer of the second micro LED (200), and may extend deeper than the entire layer or part of the layer of the first micro LED (100). As shown in Fig. 1, the common electrode (700) may extend to the uppermost depth of the first micro LED (100).

[0041] The common electrode (700) can be connected to the upper portions of the first micro LED (100), the second micro LED (200), and the third micro LED (300).

[0042] The common electrode (700) may be directly connected to a plurality of microLEDs by contact, or may be indirectly connected with another conductive material therebetween. Here, the conductive material may be a transparent electrode (ITO).

[0043] The common electrode (700) may include a common upper electrode (710) exposed on the upper side of the stacked electronic element (1), a common vertical electrode (720) extending vertically from the common upper electrode (710) toward the inside of the stacked electronic element (1), and a common horizontal electrode (730) extending horizontally from the common vertical electrode (720) toward the micro LED. The common vertical electrode (720) and / or the common horizontal electrode (730) may be provided in plurality.

[0044] The first electrode (400) can be electrically connected to the first micro LED (100). The first electrode (400) can receive a positive voltage or a negative voltage to provide current to the first micro LED (100) or receive current from the first micro LED (100). Since the first electrode (400) must be connected to the first micro LED (100), it can be provided to extend from the upper surface of the stacked electronic device (1) to the inside.

[0045] The first electrode (400) may extend deeper than the entirety of the third microLED (300), may extend deeper than the entirety of the second microLED (200), and may extend deeper than a portion of the first microLED (100). The first electrode (400) may be directly connected by contact with the first microLED (100), or may be indirectly connected with another conductive material therebetween. Here, the conductive material may be a transparent electrode (ITO).

[0046] The first electrode (400) may include a first upper electrode (410) exposed on the upper side of the stacked electronic element (1), and a first vertical electrode (420) extending vertically from the first upper electrode (410) toward the first microLED (100).

[0047] The second electrode (500) can be electrically connected to the second micro LED (200). The second electrode (500) can receive a positive voltage or a negative voltage to provide current to the second micro LED (200) or receive current from the second micro LED (200). Since the second electrode (500) must be connected to the second micro LED (200), it can be provided to extend from the upper surface of the stacked electronic device (1) to the inside.

[0048] The second electrode (500) may extend deeper than the entire third micro LED (300) and may extend deeper than a portion of the second micro LED (200). The second electrode (500) may be directly connected to the second micro LED (200) by contact, or may be indirectly connected with another conductive material therebetween. Here, the conductive material may be a transparent electrode (ITO).

[0049] The second electrode (500) may include a second upper electrode (510) exposed on the upper side of the stacked electronic element (1), and a second vertical electrode (520) extending vertically from the second upper electrode (510) toward the second microLED (200).

[0050] The third electrode (600) can be electrically connected to the third micro LED (300). The third electrode (600) can receive a positive or negative voltage to provide current to the third micro LED (300) or receive current from the third micro LED (300). Since the third electrode (600) must be connected to the third micro LED (300), it can be provided to extend from the upper surface of the stacked electronic element (1) to the inside.

[0051] The third electrode (600) may extend deeper than a portion of the third micro LED (300). The third electrode (600) may be directly connected to the third micro LED (300) by contacting it, or may be indirectly connected with another conductive material therebetween. Here, the conductive material may be a transparent electrode (340, ITO).

[0052] The third electrode (600) may include a third upper electrode (610) exposed on the upper side of the stacked electronic element (1), and a third vertical electrode (620) extending vertically toward the third microLED (300).

[0053] The first electrode (400), common electrode (700), third electrode (600), and second electrode (500) may be arranged in order from one side of the stacked electronic element (1), but are not limited thereto.

[0054] The first micro LED (100), the second micro LED (200), and the third micro LED (300) can each be driven independently, and can emit light of various colors through combination.

[0055] Referring still to FIG. 1, the microLED may be configured to include, from the bottom up, an n-type current layer, a current transport layer, a p-type layer, an active layer, and an n-type layer. Current may flow into the p-type layer through the n-type current layer and the current transport layer.

[0056] The n-type current layer may be an n-type semiconductor. The n-type current layer may also be utilized as an n-type cladding layer made of an n-type semiconductor.

[0057] The first electrode (400), the second electrode (500), and the third electrode (600) may be electrically connected to the n-type current layer. Here, 'electrically connected' means that power is transmitted from the first electrode (400), the second electrode (500), and the third electrode (600) to the microLED through the n-type current layer. However, at least one of the first electrode (400), the second electrode (500), and the third electrode (600) may be directly connected by contacting the p-type layer, or may be indirectly connected to the p-type layer with a conductive material (e.g., ITO) therebetween.

[0058] Because n-type semiconductors have lower contact resistance than p-type semiconductors, contacting electrodes to an n-type semiconductor can maximize current injection. That is, electrically connecting each electrode to the n-type current layer can increase current injection efficiency and enhance luminous efficiency compared to electrically connecting each electrode to the p-type layer.

[0059] The n-type current layer can receive current from the electrode and provide it to the current conducting layer.

[0060] The current transport layer can be located on top of the n-type current layer. The current transport layer can be located below the p-type layer. The current transport layer can distribute the current provided from the n-type current layer in the horizontal direction.

[0061] The current conducting layer may include an n-type semiconductor layer (not shown) and a p-type semiconductor layer (not shown) positioned on top of the n-type semiconductor layer. A tunnel junction effect may occur between the n-type semiconductor layer and the p-type semiconductor layer, allowing current to flow.

[0062] Because p-type semiconductors have higher resistance than n-type semiconductors, it's difficult to distribute current horizontally. Therefore, distributing current through a current transfer layer can prevent current concentration. This current concentration can narrow the light-emitting area of ​​a microLED, reducing its luminous efficiency. In other words, a current transfer layer can increase the luminous efficiency of a microLED.

[0063] The n-type current layer and the current transfer layer may be provided in at least one of the first microLED (100), the second microLED (200), and the third microLED (300).

[0064] The first microLED (100) may be configured to include, from the bottom, a first n-type current layer (150), a first current transfer layer (140), a first p-type layer (130), a first active layer (120), and a first n-type layer (110). Current may flow into the first p-type layer (130) through the first n-type current layer (150) and the first current transfer layer (140). As a result, holes may move from the first p-type layer (130) toward the first active layer (120). Electrons may move from the first n-type layer (110) toward the first active layer (120).

[0065] The second microLED (200) may be configured to include, from the bottom, a second n-type current layer (250), a second current transfer layer (240), a second p-type layer (230), a second active layer (220), and a second n-type layer (210). Current may flow into the second p-type layer (230) through the second n-type current layer (250) and the second current transfer layer (240). As a result, holes may move from the second p-type layer (230) toward the second active layer (220). Electrons may move from the second n-type layer (210) toward the second active layer (220).

[0066] Optionally, the third microLED (300) may be configured to include, from the lower layer, a third n-type current layer (not shown), a third current transfer layer (not shown), a third p-type layer (330), a third active layer (320), and a third n-type layer (310). Current may flow into the p-type layer through the third n-type current layer and the third current transfer layer. Accordingly, holes may move from the third p-type layer (330) toward the third active layer (320). Electrons may move from the third n-type layer (310) toward the third active layer (320).

[0067] The first n-type current layer (150) may be electrically connected to the first electrode (400). The second n-type current layer (250) may be electrically connected to the second electrode (500). The third n-type current layer or the third p-type layer (330) may be electrically connected to the third electrode (600). In this case, the electrical connection may include contact with a conductive material therebetween.

[0068] The first n-type layer (110) may be electrically connected to the common electrode (700). The second n-type layer (210) may be electrically connected to the common electrode (700). The third n-type layer (310) may be electrically connected to the common electrode (700). In this case, the electrical connection may include contact with a conductive material therebetween.

[0069] The first n-type layer (110) and the second n-type current layer (250) may be provided on the same layer. The first n-type layer (110) and the second n-type current layer (250) may be provided with the same material. The first n-type layer (110) and the second n-type current layer (250) may be formed by growing simultaneously.

[0070] Optionally, the second n-type layer (210) and the third n-type current layer may be provided on the same layer. The second n-type layer (210) and the third n-type current layer may be provided with the same material. The second n-type layer (210) and the third n-type current layer may be formed by growing simultaneously.

[0071] Referring to FIG. 1, the first micro LED (100) may be provided in the first micro LED layer (100'), the second micro LED (200) may be provided in the second micro LED layer (200'), and the third micro LED (300) may be provided in the third micro LED layer (300').

[0072] A microLED can constitute a portion of a microLED layer. Alternatively, a microLED can constitute the entire microLED layer. Specifically, a microLED can refer to a light-generating region. If current flows only in a portion of a microLED layer, thereby generating light only in that portion, that portion can be referred to as a microLED.

[0073] The stacked electronic device (1) can be divided into a first region (A1) on one side and a second region (A2) on the other side based on the vertical axis. The first micro LED (100) can be positioned in the first region (A1) and / or the second region (A2), the second micro LED (200) can be positioned in the first region (A1) and / or the second region (A2), and the third micro LED (300) can be positioned in the first region (A1) and / or the second region (A2). The vertical axis can be any axis, an imaginary axis, or a common electrode (700).

[0074] In a preferred embodiment, the first micro LED (100) may be a blue LED positioned in the first region (A1), the second micro LED (200) may be a green LED positioned in the second region (A2), and the third micro LED (300) may be a red LED positioned in the first region (A1) and the second region (A2). However, the embodiment of the stacked electronic device (1) is not limited to the above-described example, and may be implemented in other combinations.

[0075] When the first micro LED (100) is positioned in the first region (A1) or the second region (A2), the first micro LED layer (100') of the first region (A1) and the first micro LED layer (100') of the second region (A2) may be electrically insulated from each other. When the second micro LED (200) is positioned in the first region (A1) or the second region (A2), the second micro LED layer (200') of the second region (A2) and the second micro LED layer (200') of the first region (A1) may be electrically insulated from each other. When the third micro LED (300) is positioned in the first region (A1) or the second region (A2), the third micro LED layer (300') of the second region (A2) and the third micro LED layer (300') of the first region (A1) may be electrically insulated from each other. At this time, the insulation state may be achieved by etching the first micro LED layer (100'), the second micro LED layer (200'), and the third micro LED layer (300') so that the first region (A1) and the second region (A2) are spatially separated, respectively. Alternatively, the insulation state may be achieved by concentrating the current (or not dispersing the current) according to the resistance of each layer of the first micro LED layer (100'), the second micro LED (200'), and the third micro LED (300').

[0076] The laminated electronic device (1) may further include a protective film (20). The protective film (20) may electrically insulate the common electrode (700) and the micro LED in an area excluding the connection portion between the common electrode (700) and the micro LED. The protective film (20) may electrically insulate the first electrode (400) to the third electrode (600) and the micro LED in an area excluding the connection portion between the first electrode (400) to the third electrode (600) and the micro LED.

[0077] The protective film (20) can constitute the outer surface of the laminated electronic device (1). In addition, the protective film (20) can constitute an area of ​​the upper surface of the laminated electronic device (1) where the common electrode (700), the first electrode (400), the second electrode (500), and the third electrode (600) do not protrude. In addition, the protective film (20) can be provided between the common vertical electrode (720) and the common horizontal electrode (730) of the common electrode (700) and the micro LED, and can be provided between the first vertical electrode (420), the second vertical electrode (520), and the third vertical electrode (620) and the micro LED.

[0078] It can be provided in an area excluding the connection part of the electrode and the micro LED.

[0079] The laminated electronic device (1) may further include a bonding layer (30). When the third micro LED (300) is formed by growing on a separate substrate (10a), the bonding layer (30) may bond the second micro LED (200) and the third micro LED (300). (See FIG. 5(f)) The bonding layer (30) may be made of an insulating material. The bonding layer (30) may be made of an oxide material such as SiO2 or Y2O3.

[0080] Next, the structure and light-emitting state of the laminated electronic element (1) will be examined.

[0081] Fig. 2 is a drawing showing a state in which a first micro LED (100) emits light in an embodiment of the present invention. Fig. 3 is a drawing showing a state in which a second micro LED (200) emits light in an embodiment of the present invention. Fig. 4 is a drawing showing a state in which a third micro LED (300) emits light in an embodiment of the present invention.

[0082] Referring to FIG. 2, in an embodiment of the present invention, when power is applied to the first electrode (400) and the common electrode (700), the first microLED (100) corresponding to the first region (A1) can emit light.

[0083] The first micro LED (100) may be provided in a first region (A1) located on one side (left or right) based on the vertical axis. The first micro LED (100) may include a first n-type current layer (150) provided at the bottom, a first current transfer layer (140) provided on the first n-type current layer (150), a first p-type layer (130) provided on the first current transfer layer (140), a first active layer (120) provided on the first p-type layer (130), and a first n-type layer (110) provided on the first active layer (120). At this time, the first n-type layer (110) and the second n-type current layer (250) described later may be provided on the same layer and composed of the same material, but are not limited thereto.

[0084] The first n-type current layer (150) may be formed of an n-type semiconductor doped in GaN material. The first p-type layer (130) may be formed of a p-type semiconductor doped in GaN material. The first n-type layer (110) may be formed of an n-type semiconductor doped in GaN material.

[0085] The first n-type current layer (150) can be electrically connected to the first electrode (400) by making contact with it. Specifically, the first upper electrode (410) of the first electrode (400) can be exposed and protrude from the upper surface of the stacked electronic element (1), and the first vertical electrode (420) of the first electrode (400) can be electrically connected to the first n-type current layer (150) of the first microLED (100) by making contact with it.

[0086] The first n-type layer (110) may be electrically connected to the common electrode (700) by making contact with it. Specifically, the common upper electrode (710) of the common electrode (700) may be exposed and protrude from the upper surface of the stacked electronic device (1), the common vertical electrode (720) of the common electrode (700) may extend into the interior of the stacked electronic device (1) toward the first micro LED (100), and the common horizontal electrode (730) may be electrically connected to the first n-type layer (110) of the first micro LED (100) by making contact with it. Alternatively, the common vertical electrode (720) may be electrically connected to the first n-type layer (110) of the first micro LED (100) by making contact with it.

[0087] When power is applied to the first electrode (400) and the common electrode (700), the first micro LED (100) can emit light and emit light in a downward direction. The first micro LED (100) can be a red LED or a green LED, but is preferably a blue LED. By placing the blue LED, which has the shortest wavelength among red, green, and blue, at the bottom, the light transmission efficiency of the stacked electronic device (10) can be increased.

[0088] Referring to FIG. 3, in an embodiment of the present invention, when power is applied to the second electrode (500) and the common electrode (700), the second micro LED (200) corresponding to the second region (A2) can emit light.

[0089] The second micro LED (200) may be provided in the second region (A2) located on the other side (right or left) based on the vertical axis. The second micro LED (200) may include a second n-type current layer (250) provided at the bottom, a second current transfer layer (240) provided on the second n-type current layer (250), a second p-type layer (230) provided on the second current transfer layer (240), a second active layer (220) provided on the second p-type layer (230), and a second n-type layer (210) provided on the second active layer (220). At this time, the second n-type current layer (250) and the first n-type layer (110) may be provided on the same layer and may be composed of the same material, but are not limited thereto.

[0090] The second n-type current layer (250) may be formed of an n-type semiconductor doped in GaN material. The second p-type layer (230) may be formed of a p-type semiconductor doped in GaN material. The second n-type layer (210) may be formed of an n-type semiconductor doped in GaN material.

[0091] The second n-type current layer (250) can be electrically connected to the second electrode (500) by making contact with it. Specifically, the second upper electrode (510) of the second electrode (500) can be exposed and protrude from the upper surface of the stacked electronic element (1), and the second vertical electrode (520) of the second electrode (500) can be electrically connected to the second n-type current layer (250) of the second microLED (200) by making contact with it.

[0092] The second n-type layer (210) can be electrically connected to the common electrode (700) by making contact with it. Specifically, the common upper electrode (710) of the common electrode (700) can be exposed and protrude from the upper surface of the stacked electronic device (1), the common vertical electrode (720) of the common electrode (700) can extend into the interior of the stacked electronic device (1) toward the second micro LED (200), and the common horizontal electrode (730) can be electrically connected to the second n-type layer (210) of the second micro LED (200) by making contact with it. Alternatively, the common vertical electrode (720) can also be electrically connected to the second n-type layer (210) of the second micro LED (200) by making contact with it.

[0093] When power is applied to the second electrode (500) and the common electrode (700), the second micro LED (200) can emit light and emit light downward. The second micro LED (200) can be a red LED or a blue LED, but is preferably a green LED. By arranging a green LED with a wavelength in the middle among red, green, and blue in the center, the light transmission efficiency of the stacked electronic device (1) can be increased.

[0094] Referring to FIG. 4, in an embodiment of the present invention, when power is applied to the third electrode (600), the third micro LED (300) corresponding to the first region (A1) and the second region (A2) can emit light.

[0095] The third micro LED (300) may be provided in the first area (A1) and the second area (A2) located on one side and the other side (left and right) with respect to the vertical axis. However, the present invention is not limited thereto, and the third micro LED (300) may be provided in the first area (A1) or the second area (A2) located on one side or the other with respect to the vertical axis.

[0096] The third microLED (300) may include a third p-type layer (330) located at the bottom, a third active layer (320) provided on the third p-type layer (330), and a third n-type layer (310) provided on the third active layer (320). Alternatively, the third microLED (300) may include a third n-type current layer located at the bottom, a third current transfer layer provided on the third n-type current layer, a third p-type layer (330) provided on the third current transfer layer, a third active layer (320) provided on the third p-type layer (330), and a third n-type layer (310) provided on the third active layer (320).

[0097] The third p-type layer (330) may be formed of a p-type semiconductor that is p-doped in GaP material. The third n-type layer (310) may be formed of an n-type semiconductor that is n-doped in GaAs material.

[0098] The third p-type layer (330) can be electrically connected to the third electrode (600) by making contact with it. Specifically, the third upper electrode (610) of the third electrode (600) can be exposed and protrude from the upper surface of the stacked electronic element (1), and the third vertical electrode (620) of the third electrode (600) can be electrically connected to the third p-type layer (330) of the third microLED (300) by making contact with it. The third p-type layer (330) can be electrically connected to the third electrode (600) with a conductive material (e.g., ITO) therebetween.

[0099] The third n-type layer (310) can be electrically connected to the common electrode (700) by making contact with it. Specifically, the common upper electrode (710) of the common electrode (700) can be exposed and protrude from the upper surface of the stacked electronic device (1), and the common vertical electrode (720) of the common electrode (700) can be electrically connected to the third n-type layer (310) of the third micro LED (300) by making contact with it. The third n-type layer (310) can be electrically connected to the third electrode (600) with a conductive material therebetween. Here, the common vertical electrode (720) can be provided in plurality, and the plurality of vertical electrodes can be electrically connected to the first micro LED (100) to the third micro LED (300) by making contact with them, respectively. It can be electrically connected to a plurality of microLEDs through a plurality of common horizontal electrodes (730) extending from a common vertical electrode (720).

[0100] The third micro LED (300), like the first micro LED (100) and the second micro LED (200), includes a third n-type current layer and a third current transfer layer, and the third electrode (600) can contact the third n-type current layer to provide current.

[0101] When power is applied to the third electrode (600) and the common electrode (700), the third micro LED (300) can emit light and emit light in a downward direction. The third micro LED (300) can be a green LED or a blue LED, but preferably can be a red LED. By arranging the red LED, which has the longest wavelength among red, green, and blue, at the top, the light transmission efficiency of the stacked electronic device (1) can be increased. In addition, since the red LED has low light emission efficiency, the light emission efficiency can be increased by providing the red LED across the first region (A1) and the second region (A2).

[0102] Next, a method for manufacturing a laminated electronic device (1) will be examined.

[0103] FIGS. 5A to 5F and FIGS. 6A to 6E are drawings showing a method for manufacturing a laminated electronic device according to an embodiment of the present invention (hereinafter, “method for manufacturing a laminated electronic device”).

[0104] Referring to FIGS. 5A to 5F and 6A to 6E, a method for manufacturing a stacked electronic device includes the steps of sequentially stacking a first micro LED layer (100') and a second micro LED layer (200') on a substrate (10); the step of sequentially stacking a third micro LED layer (300') on the second micro LED layer (200'); and the first micro LED layer (100') may include, in order from the bottom, a first n-type current layer (150), a first current transfer layer (140), a first p-type layer (130), a first active layer (120), and a first n-type layer (110). The second microLED layer (200') may include, in order from the bottom, a second n-type current layer (250), a second current transfer layer (240), a second p-type layer (230), a second active layer (220), and a second n-type layer (210). The first n-type layer (110) and the second n-type current layer (250) may be the same layer and electrically connected to the common electrode (700) and the second electrode (500).

[0105] First, according to FIG. 5a, a step of sequentially stacking a first microLED layer (100') and a second microLED layer (200') on a substrate (10) can be performed.

[0106] A microLED layer can be grown on a substrate (10). The substrate (10) can be made of a material such as sapphire, GaN, SiC, MgO, MnO, or glass. However, the material of the substrate (10) is not limited to those described above.

[0107] A first micro LED layer (100') and a second micro LED layer (200') may be laminated on a substrate (10). Here, the meaning of on the substrate (10) may be interpreted to include a case where other layers, such as a buffer layer (not shown) and a u-GaN layer (not shown), are present on the substrate (10). The first micro LED layer (100') and the second micro LED layer (200') may be grown on the substrate (10) by an epitaxial process. Optionally, a third micro LED layer (300') may also be grown on the second micro LED layer (200') by an epitaxial process.

[0108] Specifically, a first micro LED layer (100') may be positioned on a substrate (10), and a second micro LED layer (200') may be positioned on the first micro LED layer (100'). At this time, the first micro LED layer (100') and the second micro LED layer (200') may partially overlap to form a shared layer. As described above, the first n-type layer (110) of the first micro LED (100) and the second n-type current layer (250) of the second micro LED may be formed as the same layer.

[0109] Next, according to FIG. 5b, a step of etching the first microLED layer (100') and the second microLED layer (200') can be performed.

[0110] The first microLED layer (100') and the second microLED layer (300') may have a portion of the edge etched.

[0111] At least a portion of the inner side of the first micro LED layer (100') and the second micro LED layer (200') may be etched in the shape of a hole. Alternatively, the first micro LED layer (100') and the second micro LED layer (200') may be etched in a shape that is separated (spatially) into one side (the first region (A1)) and the other side (the second region (A2)) based on the vertical axis.

[0112] Accordingly, the first micro LED (100) and the second micro LED (200) can be specified in the first micro LED layer (100') and the second micro LED layer (200'). For example, the first micro LED (100) can be provided in the first region (A1), and the second micro LED (200) can be provided in the second region (A2). Alternatively, the first micro LED (100) and the second micro LED (200) can be specified by concentrating the current (or not spraying the current) according to the resistance of each layer constituting the first micro LED layer (100') and the second micro LED layer (200').

[0113] The laminate of the first micro LED layer (100') and the second micro LED layer (200') can be etched so that a part of the first n-type current layer (150) is exposed upward on one side of the first region (A1).

[0114] The second micro LED layer (200') can be etched so that a portion of the second n-type current layer (250) is exposed upward on one side of the second region. Since the second n-type current layer (250) and the first n-type layer (110) can be formed of the same layer, the second micro LED layer (200') can be etched so that a portion of the first n-type layer (110) is exposed upward.

[0115] The second microLED layer (200') can be etched so that a portion of the first n-type layer (110) is exposed upward on the other side of the first region (A1).

[0116] Next, according to FIG. 5c, a step of forming a contact electrode (40) on the first micro LED (100) and the second micro LED (200) can be performed.

[0117] At least one of the above-described common vertical electrode (720), common horizontal electrode (730), first vertical electrode (420), and second vertical electrode (520) may include a contact electrode (40). The contact electrodes (40) may be formed in plurality. The contact electrodes (40) may be formed by a method such as PVD, CVD, or ALD. The plurality of contact electrodes (40) may be formed on at least a portion of the upper exposed surfaces of the first n-type current layer (150), the first n-type layer (110), the second n-type current layer (250), and the second n-type layer (210) of the first microLED (100), respectively.

[0118] Next, according to FIG. 5d, a step of forming a first protective film (21) in contact with the first microLED (100) and the second microLED (200) can be performed.

[0119] The above-described protective film (20) may include a first protective film (21). The first protective film (21) may be made of an insulating material. The first protective film (21) may be provided between the electrode and the first micro LED (100), and between the electrode and the second micro LED (200), except for the connection portion between the electrode and the micro LED. The first protective film (21) may be formed up to the height of the upper surface of the second micro LED (200), and may be etched so as to expose a portion of the contact electrode.

[0120] The first protective film (21) can constitute the side edge and the interior of the laminated electronic element (1). The first protective film (21) can be provided so as to be in contact with the contact electrode (40) except for at least a portion of the surface of the contact electrode (40). The first electrode (400), the second electrode (500), and the common electrode (700) can be formed through at least a portion of the surface.

[0121] Next, according to FIG. 5e, a step of forming at least one of the first vertical electrode (420), the second vertical electrode (520), the common vertical electrode (720), and the common horizontal electrode (730) may be performed. That is, a step of forming some of the first electrode (400), the second electrode (500), and the common electrode (700) may be performed.

[0122] The first vertical electrode (420) may be formed from the contact electrode (40) and may be formed to protrude from the upper surface of the first protective film (21). The second vertical electrode (520) may be formed from the contact electrode (40) and may be formed to protrude to the upper surface of the first protective film (21). The common vertical electrode (720) may be formed from the contact electrode (40) and may be formed to protrude to the upper surface of the first protective film (21). The common horizontal electrode (730) may be formed from the common vertical electrode (720) and may be formed to extend the contact electrode (40) in a horizontal direction.

[0123] Next, according to FIG. 5f, a step of laminating a third microLED layer (300') on a second microLED layer (200') can be performed.

[0124] The third micro LED layer (300') may be laminated on a separate substrate (10a). The third micro LED layer (300') may be grown on the separate substrate (10a) by an epitaxial process. The third micro LED (300) may be provided on the separate substrate (10a) during the growth process. The third micro LED layer (300') may be grown to include, in order from the lower layer, a third n-type layer (310), a third active layer (320), and a third p-type layer (330).

[0125] The third micro LED layer (300') can be bonded to the second micro LED (200) by the bonding layer (30). The third p-type layer (330) of the third micro LED layer (300') can be bonded to the second micro LED layer (200') by coming into contact with the bonding layer (30). At this time, the second n-type layer (210) of the second micro LED layer (200') can be bonded to the third micro LED layer (300') by coming into contact with the bonding layer (30). That is, the second micro LED layer (200') and the third micro LED layer (300') can be bonded to each other by the bonding layer (30).

[0126] According to FIG. 6a, a separate substrate (10a) can be separated from the third microLED layer (300').

[0127] The third micro LED layer (300') may be provided in reverse order, including a third p-type layer (330), a third active layer (320), and a third n-type layer (310) in order from the lower layer on the second micro LED layer (200').

[0128] Accordingly, all microLEDs of the stacked electronic device (1) can be provided with the p-type layer positioned at the bottom and the n-type layer positioned at the top.

[0129] Next, according to FIG. 6b, a step of etching the third microLED layer (300') can be performed.

[0130] The third micro LED layer (300') may be etched in the shape of a hole, at least in part, of the inner side. Alternatively, the third micro LED layer (300') may be etched in a shape that is spatially separated into one side (the first region (A1)) and the other side (the second region (A2)) based on the horizontal axis. As a result, the third micro LED (300) may be specified in the third micro LED layer (300').

[0131] When the third micro LED layer (300') is etched in the shape of a hole, the third micro LED (300) may be provided in the first region (A1) and the second region (A2). In this case, the third micro LED (300) may be interpreted as having the same concept as the third micro LED layer (300').

[0132] In contrast, when the third micro LED layer (300') is etched in a shape that is separated (insulated) based on the horizontal axis, the third micro LED (300) can be provided in the first region (A1) or the second region (A2).

[0133] The third microLED layer (300') can be etched so that a portion of the third p-type layer (330) is exposed upward on the inner side of the first region (A1) or the second region (A2).

[0134] The laminate of the third micro LED layer (300') and the bonding layer (30) can be etched so that a part of the second n-type layer (210) is exposed upward on one side or the other side of the first region (A1) or the second region (A2).

[0135] Next, according to FIG. 6c, a step of forming a contact electrode (40) on the third microLED (300) can be performed.

[0136] The third vertical electrode (620) described above may include a contact electrode (40). The contact electrode (40) may be formed in plurality. The contact electrode (40) may be a transparent electrode (ITO). The contact electrode (40) may be formed by a method such as PVD, CVD, ALD, etc. The plurality of contact electrodes (40) may be formed on at least a portion of the surface exposed to the upper portion of the third p-type layer (330) and the third n-type layer (310) of the third microLED (300).

[0137] Next, according to FIG. 6d, a step of forming a second protective film (22) in contact with the third microLED (300) can be performed.

[0138] The above-described protective film (20) may further include a second protective film (22). The second protective film (22) may be made of the same material as the first protective film (21). The second protective film (22) may be provided between the electrode and the third micro LED (300) except for the connection portion between the electrode and the third micro LED (300). The second protective film (22) may be formed to a height higher than the upper surface of the third micro LED (300) and the contact electrode (40) on the third micro LED (300), and may be etched so that a portion of the contact electrode is exposed.

[0139] The second protective film (22) may constitute the side edges, the inside, and the upper surface of the laminated electronic device. The second protective film (22) may be provided so as to contact the first electrode (400), the second electrode (500), and the common electrode (700) except for at least a portion of the surfaces of the first electrode (400), the second electrode (500), and the common electrode (700) that were partially formed in the previous step. The second protective film (22) may be provided so as to contact the contact electrode (40) except for at least a portion of the upper surface of the contact electrode (40).

[0140] Next, according to FIG. 6e, a step of forming at least one of the first vertical electrode (420), the second vertical electrode (520), the third vertical electrode (620), the common vertical electrode (720), the first upper electrode (410), the second upper electrode (510), the third upper electrode (610), and the common upper electrode (710) may be performed. That is, a step of forming and completing the remainder of the first electrode (400), the second electrode (500), the third electrode (600), and the common electrode (700) may be performed.

[0141] The remainder of the first vertical electrode (420) may be formed from some of the first vertical electrodes (420) that have already been formed, and may be formed to the height of the upper surface of the second protective film (22). The remainder of the second vertical electrode (520) may be formed from some of the second vertical electrodes (520) that have already been formed, and may be formed to the height of the upper surface of the second protective film (22). The third vertical electrode (620) may be formed from the contact electrode (40), and may be formed to the height of the upper surface of the second protective film (22). The common vertical electrode (720) may be formed from some of the common vertical electrodes (720) that have already been formed, or the common horizontal electrode (730), and may be formed to the height of the upper surface of the second protective film (22). Another common vertical electrode (720) can be formed from the contact electrode (40) and formed up to the height of the upper surface of the second protective film (22).

[0142] The first upper electrode (410), the second upper electrode (510), the third upper electrode (610), and the common upper electrode (710) are formed from the first vertical electrode (420), the second vertical electrode (520), the third vertical electrode (620), and the common vertical electrode (720), respectively, and may be formed to protrude from the upper surface of the second protective film (22). The common upper electrode (710) may electrically connect a plurality of common vertical electrodes (720).

[0143] By positioning the first electrode (400), the second electrode (500), the third electrode (600), and the common electrode (700) on the upper surface rather than in the direction of light emission, the light emission efficiency can be increased.

[0144] The stacked electronic device (1) can increase the amount of current injected and thus increase the luminous efficiency by forming the first electrode (400) and the second electrode (500) on an n-type semiconductor (n-GaN) with low contact resistance. In addition, the stacked electronic device (1) can increase the luminous efficiency by alleviating the phenomenon of current concentration flowing in the p-type layer while injecting current through the n-type semiconductor. Accordingly, the present invention can realize an electronic device with high resolution and luminous efficiency while vertically stacking individual LED layers.

[0145]

[0146] [National Research and Development Project Supporting This Invention]

[0147] - Assignment ID: 1415175486

[0148] - Assignment number: 20017391

[0149] - Ministry name: Ministry of Trade, Industry and Energy

[0150] - Project Management (Professional) Agency Name: Korea Industrial Technology Evaluation and Planning Institute

[0151] - Research Project Name: Material and Components Technology Development (R&D)

[0152] - Research Project Name: Development of Technology for Manufacturing Light Sources for Micro LED RGB Pixels with Ultra-Fine Laminated Structures of 360ppi or More at 1 Inch or More

[0153] - Contribution rate: 1 / 1

[0154] - Project execution organization name: Point Engineering Co., Ltd.

[0155] Research period: September 1, 2021 - December 31, 2024

[0156]

[0157] As described above, the present invention has been described with reference to preferred embodiments thereof, but it will be apparent to those skilled in the art that various modifications or variations may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the following claims.

[0158] [Explanation of symbols]

[0159] 1: Stacked electronic components

[0160] 10: Substrate

[0161] 10a: Separate substrate

[0162] 20: Shield

[0163] 30: Bonding layer

[0164] 40: Contact electrode

[0165] 100: First MicroLED

[0166] 100': First microLED layer

[0167] 110: 1st n-type layer

[0168] 120: First active layer

[0169] 130: 1p-type layer

[0170] 140: First current carrying layer

[0171] 150: 1st n-type current layer

[0172] 200: Second MicroLED

[0173] 200': Second microLED layer

[0174] 210: 2nd n-type layer

[0175] 220: Second active layer

[0176] 230: 2p-type layer

[0177] 240: Second current carrying layer

[0178] 250: 2nd n-type current layer

[0179] 300: Third MicroLED

[0180] 300': Third microLED layer

[0181] 310: 3rd n-type layer

[0182] 320: Third active layer

[0183] 330: 3p-type layer

[0184] 340: Transparent electrode

[0185] 400: First electrode

[0186] 410: First upper electrode

[0187] 420: First vertical electrode

[0188] 500: Second electrode

[0189] 510: Second upper electrode

[0190] 520: Second vertical electrode

[0191] 600: Third electrode

[0192] 610: Third upper electrode

[0193] 620: Third vertical electrode

[0194] 700: Common electrode

[0195] 710: Common upper electrode

[0196] 720: Common vertical electrode

[0197] 730: Common horizontal electrode

[0198] A1: Area 1

[0199] A2: Area 2

Claims

1. In a laminated electronic device formed by stacking multiple micro LEDs, 1st MicroLED; A second microLED, at least a portion of which is positioned on an upper layer of the first microLED; A third microLED positioned above the first microLED and the second microLED; A common electrode electrically connected to the first microLED, the second microLED, and the third microLED; A first electrode electrically connected to the first microLED; a second electrode electrically connected to the second microLED; and A third electrode electrically connected to the third micro LED; The first microLED to the third microLED each include an active layer, a p-type layer positioned below the active layer, and an n-type layer positioned above the active layer; A laminated electronic device, wherein at least one of the first microLED to the third microLED further comprises a current conducting layer positioned below the p-type layer; and an n-type current layer positioned below the current conducting layer.

2. In paragraph 1, The third micro LED is a red micro LED, a stacked electronic device.

3. In paragraph 1, When power is applied to the first electrode, the first microLED corresponding to the first region emits light, When power is applied to the second electrode, the second microLED corresponding to the second region emits light, A laminated electronic device in which third microLEDs corresponding to the first and second regions emit light when power is applied to the third electrode.

4. In paragraph 1, The n-type layer of the first microLED is in contact with the common electrode, and the n-type current layer of the second microLED is in contact with the second electrode. A laminated electronic device in which the n-type layer of the first microLED and the n-type current layer of the second microLED are the same layer.

5. A step of sequentially stacking a first microLED layer and a second microLED layer on a substrate; A step of laminating a third microLED layer on the second microLED layer; The first microLED layer includes, in order from the bottom, a first n-type current layer, a first current transfer layer, a first p-type layer, a first active layer, and a first n-type layer, The second microLED layer includes, in order from the bottom, a second n-type current layer, a second p-type current transfer layer, a second active layer, and a second n-type layer. A method for manufacturing a layered electronic device, wherein the first n-type layer and the second n-type current layer are the same layer and are electrically connected to a common electrode and a second electrode.

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