High-color-gamut LED chip structure and preparation method thereof

Abstract

The invention is suitable for the technical field of semiconductor LED display, and provides a high-color-gamut LED chip structure and a preparation method thereof. The high-color-gamut LED chip structure comprises a substrate material, a buffer layer, a first semiconductor layer, a green wave quantum well layer, an electron hole adjusting layer, a blue wave quantum well layer, a second semiconductor layer, a current blocking layer and a current expansion layer which are sequentially arranged from bottom to top, and further comprises a first metal electrode layer, a second metal electrode layer and a transparent insulating layer. The electron hole adjusting layer is used for controlling the distribution of electrons and holes in the green wave quantum well layer and the blue wave quantum well layer so as to adjust the wavelength and the spectral intensity of emergent light of the green wave quantum well layer; through introduction of the electron hole adjusting layer, the wavelength of a long wave and the corresponding spectral intensity can be effectively controlled, two wavelengths can be emitted from a single chip, and through introduction of double waves, the color gamut of a display screen can be improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor LED display technology, specifically a high color gamut LED chip structure and its fabrication method. Background Technology

[0002] High color gamut LED display technology has always been a goal pursued by screen manufacturers. Currently, the mainstream method to achieve high color gamut in the market is to use blue light chips to excite green phosphors and KSF phosphors. However, this method has obvious limitations and cannot achieve a color gamut greater than 99% (based on DCI-P3 and Adobe RGB standards), making it difficult to meet the stringent requirements of high color gamut in the high-end display field.

[0003] Meanwhile, existing technologies also employ quantum dot solutions to improve color gamut, but quantum dots have poor reliability in high temperature and high humidity environments and are prone to performance degradation and failure.

[0004] Therefore, in view of the above situation, there is an urgent need to provide a high color gamut LED chip structure and its fabrication method to overcome the shortcomings in current practical applications. Summary of the Invention

[0005] The purpose of this invention is to provide a high color gamut LED chip structure and its fabrication method, effectively solving the problems in the background art mentioned above.

[0006] The present invention is implemented as follows: a high color gamut LED chip structure includes, from bottom to top, a substrate material, a buffer layer, a first semiconductor layer, a green wave quantum well layer, an electron-hole modulation layer, a blue wave quantum well layer, a second semiconductor layer, a current blocking layer and a current spreading layer, and also includes a first metal electrode layer, a second metal electrode layer and a transparent insulating layer. The electron-hole modulation layer is used to control the distribution of electrons and holes in the green wave quantum well layer and the blue wave quantum well layer, so as to adjust the wavelength and spectral intensity of the light emitted from the green wave quantum well layer.

[0007] As a further aspect of the present invention, the material of the electron-hole modulation layer is one or more of ALN, GaN, AlGaN, and InGaN.

[0008] As a further aspect of the present invention, the thickness of the electron-hole modulation layer is 5-40 nm.

[0009] As a further aspect of the present invention: the peak wavelength emitted by the green wave quantum well layer is 520-545nm; The peak wavelength emitted by the blue wave quantum well layer is 445-465nm.

[0010] As a further aspect of the present invention: the green wave quantum well layer has a multi-layer structure, and the number of quantum wells is 4-12; The blue wave quantum well layer has a multi-layer structure with 4-12 quantum wells.

[0011] As a further aspect of the present invention, the substrate material is one of sapphire substrate, silicon substrate and silicon carbide substrate.

[0012] As a further aspect of the present invention, the electron-hole modulation layer can control the distribution of electrons and holes by adjusting the band width, adjusting the thickness of the quantum barrier, or adding a blocking layer in the quantum barrier.

[0013] The present invention also provides a method for preparing a high color gamut LED chip as described above, the method comprising the following steps: Step 1: Select a substrate material suitable for growing gallium nitride epitaxy, and grow a buffer layer and a first semiconductor layer sequentially on the substrate material; Step 2: Grow a green wave quantum well layer on the first semiconductor layer; Step 3: Grow an electron-hole modulation layer on the green wave quantum well layer; Step 4: Grow a blue wave quantum well layer on the electron-hole modulation layer; Step 5: Grow a second semiconductor layer on the blue wave quantum well layer to form a complete epitaxial wafer structure; Step 6: Using chip manufacturing processes, a current blocking layer and a current spreading layer are sequentially fabricated on the second semiconductor layer, and a first metal electrode layer, a second metal electrode layer, and a transparent insulating layer are fabricated to complete the chip manufacturing process.

[0014] As a further aspect of the present invention: in step two, the grown green wave quantum well layer is a multi-layer structure with 4-12 quantum wells, and the peak wavelength emitted from the green wave quantum well layer is controlled to be 520-545nm. In step four, the grown blue wave quantum well layer is a multi-layer structure with 4-12 quantum wells, and the peak wavelength emitted from the blue wave quantum well layer is controlled to be 445-465nm.

[0015] As a further aspect of the present invention: in step three, the thickness of the grown electron-hole modulation layer is 5-40 nm, and the material is one or more of ALN, GaN, AlGaN and InGaN.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention enables a single chip to emit blue and green light, with the wavelength of the green light being adjustable.

[0017] This invention can solve the performance requirements for high color gamut products in the display field, achieving a color gamut greater than 95%.

[0018] The electron-hole modulation layer of this invention can control the intensity of green light and can be used to develop products according to customer needs.

[0019] The invention has a simple design structure and can be applied to large-scale production, reducing costs. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a high color gamut LED chip structure provided by the present invention.

[0022] Figure 2 This is a schematic diagram of a traditional LED structure.

[0023] In the attached figure: 1-substrate material, 2-buffer layer, 3-first semiconductor layer, 4-green wave quantum well layer, 5-electron-hole modulation layer, 6-blue wave quantum well layer, 7-second semiconductor layer, 8-current blocking layer, 9-current spreading layer, 10-first metal electrode layer, 11-second metal electrode layer, 12-transparent insulating layer, 13-quantum well layer. Detailed Implementation

[0024] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0025] The present invention will be further explained below with reference to specific embodiments.

[0026] Please see Figure 1 This invention provides a high color gamut LED chip structure, comprising: a substrate material 1, a buffer layer 2, a first semiconductor layer 3, a green quantum well layer 4, an electron-hole modulation layer 5, a blue quantum well layer 6, a second semiconductor layer 7, a current blocking layer 8, a current spreading layer 9, a first metal electrode layer 10, a second metal electrode layer 11, and a transparent insulating layer 12. This invention effectively solves the problem of uncontrollable wavelength and spectral intensity of the blue-green dual peaks through the design of the electron-hole modulation layer 5.

[0027] The electron-hole modulation layer 5 is located in the intermediate layer region above the green wave quantum well 4 and below the blue wave quantum well 6.

[0028] The function of the electron-hole modulation layer 5 is to control the intensity and wavelength of green light by controlling the ratio of electrons and holes passing through.

[0029] The material of the electron-hole modulation layer 5 can be one or more of the following materials, but not limited to: ALN, GaN, AlGaN, InGaN, etc.

[0030] The electron-hole modulation layer 5 is used to control the electron and hole activity in the long-wavelength quantum well and the short-wavelength quantum well.

[0031] The mechanism of the electron-hole modulation layer 5 may include, but is not limited to, the following methods: adjusting the band width, adjusting the thickness of the Qb (quantum barrier), or adding a blocking layer to the Qb (quantum barrier).

[0032] The peak wavelength range emitted by the green wave quantum well 4 is between 520-545nm, and the peak wavelength range emitted by the blue wave quantum well 6 is between 445-465nm.

[0033] The thickness of the electron-hole modulation layer 5 is controlled between 5-40 nm.

[0034] In this embodiment, the present invention effectively controls the wavelength and spectral intensity of green light by introducing an electron-hole modulation layer, achieving a truly high color gamut for the product. Furthermore, this method is simple to implement and facilitates large-scale production. Compared to quantum dot solutions, it offers significant reliability advantages, addressing the poor reliability issues of quantum dots under high temperature and humidity conditions.

[0035] The present invention also provides a method for preparing a high color gamut LED chip as described above, the method comprising the following steps: Step 1: Select a substrate material 1 suitable for growing gallium nitride epitaxy, including but not limited to sapphire substrates, silicon substrates, silicon carbide substrates, etc. A buffer layer 2 and a first semiconductor layer 3 are then grown sequentially on the substrate material 1.

[0036] Step 2: Grow a green quantum well layer 4 on the first semiconductor layer 3. The quantum wells are multi-layered, and the number of quantum wells is controlled between 4 and 12. The peak wavelength of the green light is controlled between 520 and 540 nm.

[0037] Step 3: Grow an electron-hole modulation layer 5 on the green quantum well layer 4. The thickness of the electron-hole modulation layer 5 is controlled between 5-40 nm. The function of the electron-hole modulation layer 5 is to control the electron and hole activity in the long-wavelength quantum well and the short-wavelength quantum well.

[0038] Step 4: A blue quantum well layer 6 is grown on the electron-hole modulation layer 5. The quantum wells have a multi-layer structure, and the number of quantum wells is controlled between 4 and 12. The peak wavelength of the blue light is between 445 and 465 nm.

[0039] Step 5: Grow a second semiconductor layer 7 on the blue quantum well layer 6 to form a complete epitaxial wafer structure.

[0040] Step 6: Complete the chip fabrication process through chip manufacturing technology, and sequentially complete the fabrication of the current blocking layer 8, the current blocking layer 8, the current spreading layer 9, the first metal electrode layer 10, the second metal electrode layer 11, and the transparent insulating layer 12.

[0041] Example 1: A method for preparing a high color gamut LED chip as described above, the method comprising the following steps: Step 1: Select a substrate material 1 suitable for growing gallium nitride epitaxy, including but not limited to sapphire substrates, silicon substrates, silicon carbide substrates, etc. A buffer layer 2 and a first semiconductor layer 3 are then grown sequentially on the substrate material 1.

[0042] Step 2: Grow a green quantum well layer 4 on the first semiconductor layer 3. The quantum wells are multi-layered and the number of quantum wells is controlled to be between 6.

[0043] Step 3: Grow an electron-hole modulation layer 5 on the green quantum well layer 4. The thickness of the electron-hole modulation layer 5 is controlled at 19.5 nm. The peak wavelength of the green light is controlled at 532 nm.

[0044] Step 4: A blue quantum well layer 6 is grown on the electron-hole modulation layer 5. The quantum wells have a multi-layer structure, and the number of quantum wells is controlled to be 8. The peak wavelength of the blue light is 454 nm.

[0045] Step 5: Grow a second semiconductor layer 7 on the blue wave quantum well layer 6 to form a complete epitaxial wafer structure.

[0046] Step 6: Complete the chip fabrication process through chip manufacturing technology, and sequentially complete the fabrication of the current blocking layer 8, the current blocking layer 8, the current spreading layer 9, the first metal electrode layer 10, the second metal electrode layer 11, and the transparent insulating layer 12.

[0047] Step 7: Complete LED beads are prepared through encapsulation.

[0048] Example 2: The difference from Example 1 is: Step 3: Grow an electron-hole modulation layer 5 on the green quantum well layer 4. The thickness of the electron-hole modulation layer 5 is controlled at 12 nm. The peak wavelength of the green light is controlled at 532 nm.

[0049] Example 3: The difference from Example 1 is: Step 3: Grow an electron-hole modulation layer 5 on the green quantum well layer 4. The thickness of the electron-hole modulation layer 5 is controlled at 25 nm. The peak wavelength of the green light is controlled at 532 nm.

[0050] Example 4: The difference from Example 1 is: Step 3: Grow an electron-hole modulation layer 5 on the green quantum well layer 4. The thickness of the electron-hole modulation layer 5 is controlled at 19.5 nm. The peak wavelength of the green light is controlled at 525 nm.

[0051] Example 5: The difference from Example 1 is: Step 3: Grow an electron-hole modulation layer 5 on the green quantum well layer 4. The thickness of the electron-hole modulation layer 5 is controlled at 19.5 nm. The peak wavelength of the green light is controlled at 536 nm.

[0052] Comparative Example 1: The fabrication steps of a traditional LED structure are as follows: Step 1: The substrate material 1, which can be used to grow gallium nitride epitaxy, includes, but is not limited to, sapphire substrates, silicon substrates, silicon carbide substrates, etc. A buffer layer 2 and a first semiconductor layer 3 are sequentially grown on the substrate material 1.

[0053] Step 4: A quantum well layer 13 is grown on the first semiconductor layer 3. The quantum wells have a multi-layer structure, and the number of quantum wells is controlled to be 8. The peak wavelength of the blue light is 454nm.

[0054] Step 5: Grow a second semiconductor layer 7 on the quantum well layer 13 to form a complete epitaxial wafer structure.

[0055] Step 6: Complete the chip fabrication process through chip manufacturing technology, and sequentially complete the fabrication of the current blocking layer 8, the current blocking layer 8, the current spreading layer 9, the first metal electrode layer 10, the second metal electrode layer 11, and the transparent insulating layer 12.

[0056] Step 7: Complete LED chips are fabricated through encapsulation. LED chips require green phosphor and KSF phosphor.

[0057] In summary, the LED beads prepared in Examples 1-5 and the comparative examples were subjected to performance tests. The test indicators included green light intensity (relative value) and color gamut (based on the DCI-P3 standard). The test results are shown in Table 1. Table 1 Test Results

[0058] The test results above show that: The LED beads in Examples 1-5 all have a color gamut of over 98.5%, with Example 1 achieving a color gamut of 99.9%, significantly higher than the 98% of the conventional LED in the comparative example, proving that the present invention can effectively improve the color gamut of LEDs.

[0059] By adjusting the thickness of the electron-hole modulation layer 5 (Examples 1-3), the intensity of green light can be adjusted (15%-35%); by adjusting the growth parameters of the green wave quantum well layer 4 (Examples 1, 4, 5), the wavelength of green light can be adjusted (525-536nm). This demonstrates that the design of the electron-hole modulation layer 5 and the green wave quantum well layer 4 can achieve controllable adjustment of the wavelength and intensity of green light, meeting different application requirements.

[0060] 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 high color gamut LED chip structure, characterized in that, It comprises, from bottom to top, a substrate material (1), a buffer layer (2), a first semiconductor layer (3), a green wave quantum well layer (4), an electron hole adjusting layer (5), a blue wave quantum well layer (6), a second semiconductor layer (7), a current blocking layer (8) and a current spreading layer (9), and further comprises a first metal electrode layer (10), a second metal electrode layer (11) and a transparent insulating layer (12). The electron hole adjusting layer (5) is used for controlling the distribution of electrons and holes in the green wave quantum well layer (4) and the blue wave quantum well layer (6), so as to adjust the wavelength and spectral intensity of the light emitted by the green wave quantum well layer (4).

2. The high color gamut LED chip structure of claim 1, wherein, The material of the electron hole adjusting layer (5) is one or more of ALN, GaN, AlGaN and InGaN.

3. The high color gamut LED chip structure according to claim 1 or 2, characterized in that, The thickness of the electron hole adjusting layer (5) is 5-40nm.

4. The high color gamut LED chip structure of claim 1, wherein, The peak wavelength emitted by the green wave quantum well layer (4) is 520-545nm. The peak wavelength emitted by the blue wave quantum well layer (6) is 445-465nm.

5. The high color gamut LED chip structure according to claim 1 or 4, wherein, The green wave quantum well layer (4) is a multi-layer structure, and the number of quantum wells is 4-12. The blue wave quantum well layer (6) is a multi-layer structure, and the number of quantum wells is 4-12.

6. The high color gamut LED chip structure of claim 1, wherein, The substrate material (1) is one of sapphire substrate, silicon substrate and silicon carbide substrate.

7. The high color gamut LED chip structure of claim 1, wherein, The electron hole adjusting layer (5) controls the distribution of electrons and holes by adjusting the energy band width, adjusting the quantum barrier thickness or adding a barrier layer in the quantum barrier.

8. A method of making a high gamut LED chip as claimed in any one of claims 1-7, characterized in that, The method comprises the following steps: Step one: select a substrate material (1) that can be used for growing gallium nitride epitaxy, and grow a buffer layer (2) and a first semiconductor layer (3) on the substrate material (1) in sequence; Step two: grow a green wave quantum well layer (4) on the first semiconductor layer (3); Step three: grow an electron hole adjusting layer (5) on the green wave quantum well layer (4); Step four: grow a blue wave quantum well layer (6) on the electron hole adjusting layer (5); Step five: grow a second semiconductor layer (7) on the blue wave quantum well layer (6) to form a complete epitaxial wafer structure; Step six: through chip manufacturing process, prepare a current blocking layer (8) and a current spreading layer (9) on the second semiconductor layer (7) in sequence, and prepare a first metal electrode layer (10), a second metal electrode layer (11) and a transparent insulating layer (12), and complete the chip process.

9. The method of claim 8, wherein, In step two, the grown green wave quantum well layer (4) is a multi-layer structure, and the number of quantum wells is 4-12, and the peak wavelength emitted by the green wave quantum well layer (4) is controlled to be 520-545nm; In step four, the grown blue wave quantum well layer (6) is a multi-layer structure, and the number of quantum wells is 4-12, and the peak wavelength emitted by the blue wave quantum well layer (6) is controlled to be 445-465nm.

10. The method of claim 8, wherein, In step three, the grown electron hole adjusting layer (5) has a thickness of 5-40nm, and the material is one or more of ALN, GaN, AlGaN and InGaN.

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