Miniature LED structure and display device

Abstract

The utility model provides a miniature LED structure and a display device, and relates to the field of semiconductor display manufacturing. The miniature LED structure comprises an N-type semiconductor layer, a quantum hydrazine layer and a P-type semiconductor layer which are arranged in sequence, and further comprises a passivation layer. The passivation layer comprises a light absorption layer and a first protection layer, the light absorption layer covers the N-type semiconductor layer, the quantum hydrazine layer and the P-type semiconductor layer, and the first protection layer covers the light absorption layer. In the miniature LED structure, the light absorption layer can absorb the light which is transversely propagated to the side surfaces of the chips, so that the light crosstalk phenomenon between the chips is weakened, and the display effect of the whole miniature LED structure is favorably improved. Besides, the light absorption layer is covered with the first protection layer, the light absorption layer can be isolated from the external environment, the light absorption layer is not prone to being eroded in the follow-up machining process and the long-term use process, and the light absorption layer can stably and effectively absorb transversely-propagating light.

Description

Technical Field

[0001] The utility model relates to the field of semiconductor display manufacturing, and in particular to a micro LED structure and a display device. Background Art

[0002] Micro-LED (Micro Light Emitting Diode, Micro-LED) technology, also known as LED miniaturization and matrix technology, refers to the integration of high-density and tiny-sized LEDs on a single chip, so that each pixel of the LED display can be addressed and individually driven to light up, reducing the pixel level from millimeter level to micron level.

[0003] As the feature size continues to decrease and the gap between pixels becomes smaller, the light emitted by the micro LED chip will propagate laterally in the epitaxial layer in the form of an optical waveguide. Eventually, some of the light will be emitted from the side of the chip and propagate laterally to illuminate the adjacent chip, causing optical crosstalk. Utility Model Content

[0004] In order to solve the optical crosstalk problem existing in existing micro LED chips, one of the objectives of the present invention is to provide a micro LED structure.

[0005] The utility model provides the following technical solutions:

[0006] A micro LED structure comprises an N-type semiconductor layer, a quantum hydrazine layer and a P-type semiconductor layer arranged in sequence, and also comprises a passivation layer;

[0007] The passivation layer includes a light absorbing layer and a first protective layer. The light absorbing layer covers the N-type semiconductor layer, the quantum hydrazine layer and the P-type semiconductor layer. The first protective layer covers the light absorbing layer.

[0008] As a further optional solution for the micro LED structure, the passivation layer further includes a second protective layer, the second protective layer covers the N-type semiconductor layer, the quantum hydrazine layer and the P-type semiconductor layer, and the light absorption layer covers the second protective layer.

[0009] As a further optional solution for the micro LED structure, the first protective layer and the second protective layer are both aluminum oxide layers.

[0010] As a further optional solution for the micro LED structure, the thickness of the first protective layer is H1, 30nm≤H1≤100nm; and / or

[0011] The thickness of the second protective layer is H2, 30nm≤H2≤100nm.

[0012] As a further optional solution for the micro LED structure, the first protective layer and / or the second protective layer includes / or comprises stacked single atomic films.

[0013] As a further optional solution to the micro LED structure, the light absorbing layer is a black photoresist layer.

[0014] As a further optional solution for the micro LED structure, the light shading rate of the light absorption layer is R, and R is ≥ 99.9999%.

[0015] As a further optional solution for the micro LED structure, the micro LED structure also includes a transparent conductive layer and a metal layer, the transparent conductive layer is arranged on the side of the P-type semiconductor layer away from the quantum hydrazine layer, the metal layer is arranged on the side of the transparent conductive layer away from the P-type semiconductor layer, the light absorbing layer is also covered on the metal layer, and part of the metal layer is exposed outside the light absorbing layer.

[0016] As a further optional solution to the micro LED structure, the micro LED structure further includes a metal block and a driving substrate;

[0017] The metal block is arranged on the side of the metal layer away from the transparent conductive layer, one end of the metal block is connected to the metal layer exposed outside the light absorbing layer, and the other end of the metal block has a bonding portion, which covers a portion of the light absorbing layer and is connected to the driving substrate.

[0018] Another object of the present invention is to provide a display device.

[0019] The utility model provides the following technical solutions:

[0020] A display device includes the above-mentioned micro LED structure.

[0021] The embodiments of the present utility model have the following beneficial effects:

[0022] In the aforementioned micro-LED structure, the passivation layer includes a light-absorbing layer and a first protective layer. The light-absorbing layer covers the N-type semiconductor layer, the quantum hydrazine layer, and the P-type semiconductor layer, absorbing light that propagates laterally to the sides of the chip, thereby reducing optical crosstalk between chips and improving the display quality of the entire micro-LED structure. Furthermore, the first protective layer covers the light-absorbing layer, isolating it from the external environment. This prevents the light-absorbing layer from being corroded during subsequent processing and long-term use, thus facilitating the light-absorbing layer to stably and effectively absorb laterally propagating light.

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 The figure shows a schematic diagram of the overall structure of a micro LED structure provided by an embodiment of the present utility model;

[0026] Figure 2 A schematic diagram showing a state of a micro LED structure provided by an embodiment of the present utility model before a passivation layer is arranged;

[0027] Figure 3 FIG2 shows a schematic diagram of the overall structure of a micro LED structure provided by another embodiment of the present invention;

[0028] Figure 4 A schematic diagram showing a state of a micro-LED structure provided by an embodiment of the present invention after depositing a second protective layer is shown;

[0029] Figure 5 A schematic diagram of the state of a micro LED structure provided by an embodiment of the present utility model after laying a light absorption layer is shown.

[0030] Description of main component symbols:

[0031] 100 - substrate; 200 - N-type semiconductor layer; 300 - quantum hydrazine layer; 400 - P-type semiconductor layer; 500 - passivation layer; 510 - light absorption layer; 520 - first protective layer; 530 - second protective layer; 600 - transparent conductive layer; 700 - metal layer; 800 - metal block; 900 - driving substrate. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0033] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. Conversely, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0034] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium, internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in the template description herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] With the improvement of microelectronics process level, the feature size continues to decrease, which also puts higher requirements on the passivation layer structure used in the Micro-LED structure, such as the need to achieve high step coverage, high conformality, good film uniformity, high film quality, and low conductivity coefficient.

[0038] Furthermore, as feature sizes continue to shrink and the gaps between pixels become smaller, light emitted by the Micro-LED chip propagates laterally in the epitaxial layer as an optical waveguide. Eventually, some light will exit the side of the chip and propagate laterally, illuminating adjacent chips. Optical crosstalk, caused by this lateral light propagation, has become a technical challenge plaguing Micro-LED displays.

[0039] The commonly used SiNx passivation layer has the disadvantage of insufficient step coverage for the small feature size of Micro-LEDs, and since the SiNx material is colorless, it causes serious optical crosstalk.

[0040] Example

[0041] Regarding the above-mentioned problems of insufficient step coverage and severe optical crosstalk in the passivation layer, please refer to Figure 1 This embodiment provides a micro LED structure. The micro LED structure includes an N-type semiconductor layer 200, a quantum dot layer 300, and a P-type semiconductor layer 400, which are sequentially arranged, and also includes a passivation layer 500.

[0042] The passivation layer 500 includes a light absorbing layer 510 and a first protective layer 520 . The light absorbing layer 510 covers the N-type semiconductor layer 200 , the quantum hydrazine layer 300 and the P-type semiconductor layer 400 , and the first protective layer 520 covers the light absorbing layer 510 .

[0043] In the aforementioned micro-LED structure, the passivation layer 500 includes a light-absorbing layer 510 and a first protective layer 520. The light-absorbing layer 510 covers the N-type semiconductor layer 200, the quantum hydrazine layer 300, and the P-type semiconductor layer 400, absorbing light that propagates laterally to the sides of the chip, thereby reducing optical crosstalk between chips and improving the display quality of the entire micro-LED structure. Furthermore, the first protective layer 520 covers the light-absorbing layer 510, isolating it from the external environment. This prevents the light-absorbing layer 510 from erosion during subsequent processing and long-term use, facilitating stable and effective absorption of laterally propagating light by the light-absorbing layer 510.

[0044] In some embodiments, the micro LED structure further includes a substrate 100 .

[0045] Specifically, the substrate 100 may be a sapphire substrate 100 , the N-type semiconductor layer 200 may be an N-type gallium nitride layer, and the P-type semiconductor layer 400 may be a P-type gallium nitride layer.

[0046] Please combine Figure 2 When preparing the above micro-LED structure, an N-type semiconductor layer 200 is grown on a substrate 100, a quantum dot layer 300 is grown on the N-type semiconductor, and a P-type semiconductor layer 400 is grown on the quantum dot layer 300. Thus, the substrate 100, the N-type semiconductor layer 200, the quantum dot layer 300, and the P-type semiconductor layer 400 are arranged in order from bottom to top.

[0047] On this basis, the P-type semiconductor layer 400, the quantum hydrazine layer 300 and part or all of the N-type semiconductor layer 200 are etched to form multiple mutually spaced chips, and steps are formed at the edges of the chips. Then, a passivation layer 500 is arranged to cover the steps.

[0048] In some embodiments, the above-mentioned micro LED structure further includes a transparent conductive layer 600 and a metal layer 700 , and the transparent conductive layer 600 is arranged on the side of the P-type semiconductor layer 400 away from the quantum hydrazine layer 300 , and the metal layer 700 is arranged on the side of the transparent conductive layer 600 away from the P-type semiconductor layer 400 .

[0049] At the same time, the light absorbing layer 510 also covers the metal layer 700 , and a portion of the metal layer 700 is exposed outside the light absorbing layer 510 .

[0050] In other embodiments, the light absorbing layer 510 may not cover the metal layer 700 but only cover a portion of the top of the transparent conductive layer 600. The remaining portion of the top of the transparent conductive layer 600 is exposed outside the light absorbing layer 510 and connected to the metal layer 700.

[0051] Alternatively, the light absorbing layer 510 may not cover the transparent conductive layer 600, but only cover a portion of the top of the P-type semiconductor layer 400. The remaining portion of the top of the P-type semiconductor layer 400 is exposed outside the light absorbing layer 510 and connected to the transparent conductive layer 600.

[0052] See also Figure 3 In some embodiments, the micro LED structure further includes a metal block 800 and a driving substrate 900 .

[0053] The metal block 800 is disposed on the side of the metal layer 700 facing away from the transparent conductive layer 600. One end of the metal block 800 is connected to the portion of the metal layer 700 exposed outside the light absorbing layer 510. The other end of the metal block 800 has a bonding portion 810. The bonding portion 810 covers a portion of the light absorbing layer 510 and is connected to the drive substrate 900.

[0054] As mentioned above, when preparing the above-mentioned micro LED structure, the P-type semiconductor layer 400, the quantum dot layer 300 and part or all of the N-type semiconductor layer 200 are etched to form a plurality of chips spaced apart from each other.

[0055] On this basis, the transparent conductive layer 600, metal layer 700, and metal block 800 further disposed on the P-type semiconductor layer 400 are also part of the chip. Multiple chips are arranged in an array to form a micro LED chip array, and are flip-chip bonded to the driver substrate 900 via bonding portions 810 within each chip.

[0056] In some embodiments, the light absorbing layer 510 is a black photoresist layer.

[0057] Specifically, the black photoresist layer is laid by photolithography, which can better absorb the light emitted from the side of the chip.

[0058] Furthermore, the light absorbing layer 510 has a light shielding rate R, which satisfies R≥99.9999%.

[0059] At this time, the light absorbing layer 510 can absorb most of the light emitted from the side of the chip, thereby effectively reducing the optical crosstalk phenomenon and greatly improving the display effect.

[0060] Optionally, the thickness of the light absorbing layer 510 is 1 μm.

[0061] Please refer again Figure 1 In some embodiments, the passivation layer 500 further includes a second protective layer 530 . The second protective layer 530 covers the N-type semiconductor layer 200 , the quantum dot layer 300 , and the P-type semiconductor layer 400 . The light absorbing layer 510 covers the second protective layer 530 .

[0062] The second protective layer 530 cooperates with the first protective layer 520 to cover the light absorbing layer 510, which can better isolate the light absorbing layer 510 from the external environment and protect the light absorbing layer 510 from being corroded. Specifically, it can protect the light absorbing layer 510 from being corroded by organic solvents during subsequent processing.

[0063] Furthermore, the first protective layer 520 and the second protective layer 530 are both aluminum oxide layers.

[0064] Compared with SiNx materials, the aluminum oxide layer is denser, more conformal, has better film uniformity, and higher film quality, which can ensure high coverage at the step position and effectively prevent leakage current caused by pinholes, moisture, ions or other external contaminants, thereby reducing electrical performance degradation and helping to maintain device stability.

[0065] In some embodiments, the thickness of the first protection layer 520 is H1, satisfying 30 nm ≤ H1 ≤ 100 nm.

[0066] It is understood that a thickness of the first protective layer 520 of not less than 30 nm can achieve the required step coverage and fully cover the light absorbing layer 510. Furthermore, a thickness of the first protective layer 520 of not more than 100 nm can shorten the time required to prepare the first protective layer 520, thereby improving production efficiency.

[0067] Based on the same consideration, the thickness of the second protection layer 530 is H2, which satisfies 30 nm ≤ H2 ≤ 100 nm.

[0068] Optionally, the thickness of the first protective layer 520 and the thickness of the second protective layer 530 can be 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, or any value between 30 nm and 100 nm. In addition, the thickness of the first protective layer 520 and the thickness of the second protective layer 530 can be the same or different.

[0069] Furthermore, the first protective layer 520 and / or the second protective layer 530 are composed of stacked single atomic films, which have higher density and better uniformity.

[0070] Specifically, the first protective layer 520 and / or the second protective layer 530 are prepared by atomic layer deposition technology.

[0071] Taking the second protective layer 530 as an example, during the preparation process, an atomic deposition device is used to deposit single atomic films layer by layer on the outer surfaces of the N-type semiconductor layer 200, the quantum hydrazine layer 300, the P-type semiconductor layer 400, the transparent conductive layer 600 and the metal layer 700, and the second protective layer 530 is formed by stacking multiple layers of single atomic films.

[0072] See also Figure 4 When preparing the passivation layer 500, an atomic deposition device is first used to deposit a layer of aluminum oxide on the outer surfaces of the N-type semiconductor layer 200, the quantum hydrazine layer 300, the P-type semiconductor layer 400, the transparent conductive layer 600, and the metal layer 700 to form a second protective layer 530, and a portion of the top area of ​​the metal layer 700 is exposed.

[0073] For example, a layer of photoresist may be first deposited on top of the metal layer 700 , and then a layer of aluminum oxide may be deposited. The photoresist may then be stripped off to form the second protective layer 530 , with a portion of the top of the metal layer 700 exposed outside the second protective layer 530 .

[0074] Alternatively, a layer of aluminum oxide may be deposited first, and then a layer of photoresist may be laid on the area other than the portion on the top of the metal layer 700 that needs to be exposed, and then part of the aluminum oxide may be etched away to form a second protective layer 530, and part of the area on the top of the metal layer 700 may be exposed outside the second protective layer 530, and finally the photoresist may be removed.

[0075] See also Figure 5 After forming the second protective layer 530 , a light absorbing layer 510 is formed by photolithography to cover the second protective layer 530 .

[0076] Please refer again Figure 1Then, the step of depositing aluminum oxide is repeated to form a first protective layer 520 , thereby obtaining a final passivation layer 500 structure.

[0077] In summary, the aforementioned micro-LED structure utilizes a second protective layer 530, a light absorbing layer 510, and a first protective layer 520 stacked sequentially to form a sandwich-structured passivation layer 500, which covers the N-type semiconductor layer 200, the quantum hydrazine layer 300, the P-type semiconductor layer 400, the transparent conductive layer 600, and the metal layer 700. This passivation layer 500 not only performs the functions of existing passivation layers but also offers the advantage of high step coverage, improving the problem of insufficient step coverage in existing passivation layers. It also absorbs light that propagates laterally to the sides of the chip, thereby reducing optical crosstalk between chips and improving the display quality of the entire micro-LED structure.

[0078] In addition, in the passivation layer 500, the first protective layer 520 and the second protective layer 530 enclose the light absorbing layer 510, which can isolate the light absorbing layer 510 from the external environment, making the light absorbing layer 510 less susceptible to corrosion during subsequent processing and long-term use, which is beneficial for the light absorbing layer 510 to stably and effectively absorb laterally propagating light.

[0079] This embodiment further provides a display device including the above-mentioned micro-LED structure.

[0080] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not limiting, and thus other examples of the exemplary embodiments may have different values.

[0081] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0082] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the scope of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A micro LED structure, characterized in that: It includes an N-type semiconductor layer, a quantum hydrazine layer and a P-type semiconductor layer arranged in sequence, and also includes a passivation layer; The passivation layer includes a light absorbing layer and a first protective layer. The light absorbing layer covers the N-type semiconductor layer, the quantum hydrazine layer and the P-type semiconductor layer. The first protective layer covers the light absorbing layer.

2. The micro-LED structure according to claim 1, wherein: The passivation layer further includes a second protective layer, the second protective layer covers the N-type semiconductor layer, the quantum hydrazine layer and the P-type semiconductor layer, and the light absorption layer covers the second protective layer.

3. The micro-LED structure according to claim 2, wherein: The first protective layer and the second protective layer are both aluminum oxide layers.

4. The micro-LED structure according to claim 3, wherein: The thickness of the first protective layer is H1, 30nm≤H1≤100nm; and / or The thickness of the second protective layer is H2, 30nm≤H2≤100nm.

5. The micro-LED structure according to claim 3, wherein: The first protective layer and / or the second protective layer include stacked monoatomic films.

6. The micro-LED structure according to any one of claims 1 to 5, characterized in that: The light absorbing layer is a black photoresist layer.

7. The micro-LED structure according to any one of claims 1 to 5, characterized in that: The light absorbing layer has a light shielding rate R, where R is greater than or equal to 99.9999%.

8. The micro-LED structure according to any one of claims 1 to 5, characterized in that: The micro LED structure also includes a transparent conductive layer and a metal layer. The transparent conductive layer is arranged on the side of the P-type semiconductor layer away from the quantum hydrazine layer, and the metal layer is arranged on the side of the transparent conductive layer away from the P-type semiconductor layer. The light absorption layer also covers the metal layer, and part of the metal layer is exposed outside the light absorption layer.

9. The micro-LED structure according to claim 8, wherein: The micro LED structure further includes a metal block and a driving substrate; The metal block is arranged on the side of the metal layer away from the transparent conductive layer, one end of the metal block is connected to the metal layer exposed outside the light absorbing layer, and the other end of the metal block has a bonding portion, which covers a portion of the light absorbing layer and is connected to the driving substrate.

10. A display device, characterized in that: The micro LED structure comprises the micro LED structure according to any one of claims 1 to 9.

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