LED chip and preparation method thereof, semiconductor light emitting element

Abstract

The present invention relates to the technical field of light-emitting diodes, and in particular, to an LED chip and a preparation method thereof, and a semiconductor light-emitting element. The LED chip includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer. The light-emitting layer includes a green light-emitting area, a blue light-emitting area, and a supplementary light-emitting area; the In concentration of the supplementary light layer is ≥ the In concentration of the blue light layer, and the thickness of the supplementary light layer is > the thickness of the blue light layer. By growing the supplementary light-emitting area after the blue light-emitting area, the well layer of the supplementary light-emitting area is thicker and has a lower energy barrier, which can pull the energy band of the entire light-emitting area, change the distribution of carriers in the entire quantum well, and make the carrier distribution closer to the second semiconductor layer side. In addition, because the supplementary area has a thicker light layer, it can buffer the mismatch stress generated by the second semiconductor layer behind it, reduce the damage to the light-emitting area caused by subsequent growth, and thus improve the brightness of the entire device; finally, the wavelength of the supplementary light emission is close to that of the blue light-emitting area, which can enhance the intensity of the blue light-emitting area.

Description

Technical Field

[0001] The present invention relates to the technical field of light emitting diodes, and in particular to an LED chip and a preparation method thereof, and a semiconductor light emitting element. Background Art

[0002] Light Emitting Diode (LED) can efficiently convert electrical energy into light energy. It is a light-emitting device that releases energy and emits light through the recombination of electrons and holes. It is widely used in lighting, display and other fields.

[0003] In particular, in order to improve the display effect of display devices used as backlight light sources, the industry is actively researching a monolithic light-emitting element having multiple active layers emitting light of different wavelengths without using or using less phosphors. For example, red, blue and green active layers, or blue and orange active layers are implemented in a single light-emitting device, or the blue and green active layers as part thereof are implemented as a single light-emitting device, which can be implemented in one device by combining another red light-emitting device.

[0004] However, in the prior art, the multi-wavelength light-emitting layer single light-emitting element, such as patent CN101197416A, usually grows a green light-emitting quantum well layer first on the semiconductor close to the N-type layer, and then grows a blue light quantum well layer, or continues to grow an ultraviolet light-emitting quantum well layer and then grows a P-type semiconductor layer. This multi-quantum well structure has the following problems: (1) The blue light-emitting region has the lowest In content in the entire quantum well region, so its energy barrier is the highest, and carriers are least likely to recombine here to produce photons, affecting the brightness; (2) The green light-emitting region is farthest from the second semiconductor in the entire quantum well region, resulting in a low efficiency of holes entering the green light-emitting region and a weak wavelength intensity emitted by the green light-emitting region.

[0005] Existing LED designs that emit blue and green dual-color light simultaneously generally have the problem of weak blue light intensity due to the low energy gap of green light. The weak blue light intensity in the blue-green dual-color chip will result in it being unable to provide sufficient energy in the subsequent process of exciting the fluorescence peak, thereby affecting the luminous efficiency of the entire device.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The first purpose of the present invention is to provide an LED chip, by growing a supplementary light-emitting area after the blue light-emitting area, the well layer of the supplementary light-emitting area is thicker, and its energy barrier is lower, which can pull the energy band of the entire light-emitting area, change the distribution of carriers in the entire quantum well, and make the carrier distribution closer to the second semiconductor layer side, and the supplementary area has a thicker hydrazine layer, which can buffer the mismatch stress generated by the second semiconductor layer behind, reduce the damage to the light-emitting area caused by subsequent growth, and thus improve the brightness of the entire device; finally, the wavelength of the supplementary light is close to that of the blue light-emitting area, which can enhance the intensity of the blue light-emitting area. The present invention solves the problem of weak blue light luminescence intensity in the blue-green dual-color LED chip in the prior art.

[0008] The second object of the present invention is to provide a method for preparing an LED chip.

[0009] A third object of the present invention is to provide a semiconductor light emitting element.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0011] The present invention first provides an LED chip, comprising a substrate, a first semiconductor layer, a light-emitting layer, and a second semiconductor layer, wherein the light-emitting layer comprises a green light-emitting region, a blue light-emitting region, and a supplementary light-emitting region sequentially arranged on the first semiconductor layer;

[0012] The In concentration of the supplementary layer in the supplementary light emitting area is ≥ the In concentration of the blue light layer in the blue light emitting area, and / or the thickness of the supplementary layer in the supplementary light emitting area is > the thickness of the blue light layer in the blue light emitting area.

[0013] Preferably, the wavelength range of the green light emitted by the green light emitting area is 490nm~570nm.

[0014] Preferably, the wavelength range of the blue light emitted by the blue light emitting area is 410nm~480nm.

[0015] Preferably, the wavelength range of the supplementary light emitted by the supplementary light-emitting area is 410nm~480nm.

[0016] Preferably, the ratio of the thickness of the supplementary hydrazine layer in the supplementary light-emitting region to the thickness of the blue light hydrazine layer in the blue light-emitting region is 1-5:1, preferably 1.1-3.5:1.

[0017] Preferably, the In concentration of the green light emitting layer in the green light emitting region is greater than the In concentration of the supplementary light emitting layer in the supplementary light emitting region.

[0018] Preferably, the thickness of the green light emitting layer in the green light emitting region is ≥ the thickness of the blue light emitting layer in the blue light emitting region.

[0019] Preferably, the green light emitting region includes In x1 Ga 1-x1 A periodic structure in which N green light well layers and GaN-based green light barrier layers are alternately arranged and the period number is ≥1.

[0020] Preferably, the blue light emitting area includes In x2 Ga 1-x2 A periodic structure in which N blue light well layers and GaN-based blue light barrier layers are alternately arranged with a period number of ≥3.

[0021] Preferably, the supplementary light emitting area includes In x3 Ga 1-x3 A periodic structure in which N-based supplementary well layers and GaN-based supplementary barrier layers are alternately arranged with a period number ≥ 1.

[0022] Preferably, the number of the supplementary hydrazine layers in the supplementary light-emitting region is less than the number of the blue light hydrazine layers in the blue light-emitting region.

[0023] Preferably, a fourth light emitting area is further included between the green light emitting area and the blue light emitting area.

[0024] Preferably, the In concentration of the green light emitting layer in the green light emitting region is greater than the In concentration of the fourth well layer in the fourth light emitting region and greater than the In concentration of the blue light emitting layer in the blue light emitting region.

[0025] Preferably, the fourth light emitting area includes In x4 Ga 1-x4 A periodic structure in which the N fourth well layer and the GaN-based fourth barrier layer are alternately arranged with a period number of ≥1.

[0026] Preferably, the wavelength range of the blue light emitted by the fourth light-emitting area is 440nm~480nm.

[0027] Preferably, the wavelength of the green light emitted by the green light emitting area>the wavelength of the blue light emitted by the fourth light emitting area>the wavelength of the supplementary light emitted by the supplementary light emitting area.

[0028] Preferably, the green light emitting zone, the fourth light emitting zone, the blue light emitting zone and the supplementary light emitting zone all include a periodic structure in which well layers and barrier layers are alternately arranged, and the period number of the blue light emitting zone ≥ the period number of the fourth light emitting zone ≥ the period number of the green light emitting zone ≥ the period number of the supplementary light emitting zone.

[0029] Preferably, a fifth light-emitting zone is further included between the green light-emitting zone and the fourth light-emitting zone, and the In concentration of the green light hydrazine layer in the green light-emitting zone is greater than the In concentration of the fifth well layer in the fifth light-emitting zone, greater than the In concentration of the fourth well layer in the fourth light-emitting zone, and greater than the In concentration of the blue light hydrazine layer in the blue light-emitting zone.

[0030] Preferably, the thickness of the green light hydrazine layer in the green light emitting region is ≥ the thickness of the fourth well layer in the fourth light emitting region is ≥ the thickness of the fifth well layer in the fifth light emitting region.

[0031] Preferably, the light-emitting layer further comprises a red light-emitting region disposed between the first semiconductor layer and the green light-emitting region, and light emitted by the red light-emitting region, the green light-emitting region, the blue light-emitting region and the supplementary light-emitting region are mixed to form white light.

[0032] Preferably, the wavelength range of the red light emitted by the red light emitting area is 590nm~780nm.

[0033] Preferably, the In concentration of the red light emitting layer in the red light emitting region is greater than the In concentration of the green light emitting layer in the green light emitting region.

[0034] Preferably, the number of red light emitting layers in the red light emitting region is less than the number of blue light emitting layers in the blue light emitting region.

[0035] Preferably, the sum of the number of red light emitting layers in the red light emitting region and the number of green light emitting layers in the green light emitting region is less than the number of blue light emitting layers in the blue light emitting region.

[0036] Preferably, a buffer layer is provided between the substrate and the first semiconductor layer.

[0037] Preferably, the buffer layer includes an AlN buffer layer and / or a GaN buffer layer.

[0038] Preferably, the GaN buffer layer in the buffer layer is one layer or multiple layers.

[0039] Preferably, the GaN buffer layer in the buffer layer is doped with Al element.

[0040] Preferably, a stress release layer is provided between the first semiconductor layer and the green light emitting area.

[0041] Preferably, the stress release layer includes at least one GaN layer and / or at least one InGaN layer.

[0042] Preferably, the stress release layer is doped with Si element and / or Al element.

[0043] The present invention further provides a method for preparing the LED chip, comprising the following steps: sequentially growing a first semiconductor layer, a green light emitting region, a blue light emitting region, a supplementary light emitting region and a second semiconductor layer on a substrate.

[0044] The present invention also provides a semiconductor light emitting element, comprising the LED chip, having a top surface as a light emitting surface, a bottom surface provided with an N electrode and a P electrode, and a side surface connecting the top surface and the bottom surface;

[0045] A fluorescent film layer, covering at least the top surface of the LED chip;

[0046] The packaging layer covers the periphery of the fluorescent film layer and the periphery and lower surface of the LED chip, and at least exposes the lower end surfaces of the N electrode and the P electrode.

[0047] Preferably, the fluorescent film layer covers four sides of the LED chip;

[0048] Preferably, the fluorescent film layer comprises a silica gel layer containing fluorescent powder, and the fluorescent powder comprises red fluorescent powder.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The LED chip provided by the present invention satisfies the relationship between In concentration or layer thickness. The additional light-emitting area can fully release the stress between the light-emitting quantum well layer and the second semiconductor layer, thereby solving the problem of weak light intensity in the blue light-emitting area.

[0051] (2) The LED chip provided by the present invention grows a supplementary light-emitting area after the blue light-emitting area. The well layer of the supplementary light-emitting area is thicker and has a lower energy barrier, which can pull the energy band of the entire light-emitting area and change the distribution of carriers in the entire quantum well, so that the carrier distribution is closer to the second semiconductor layer side. In addition, since the supplementary area has a thicker hydrazine layer, it can buffer the mismatch stress generated by the second semiconductor layer behind it, reduce the damage to the light-emitting area caused by subsequent growth, and thus improve the brightness of the entire device; finally, the wavelength of the supplementary light is close to that of the blue light-emitting area, which can enhance the intensity of the blue light-emitting area. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 A schematic diagram of the first structure of the LED chip provided by the present invention;

[0054] Figure 2 A second structural schematic diagram of the LED chip provided by the present invention;

[0055] Figure 3 A third structural schematic diagram of the LED chip provided by the present invention;

[0056] Figure 4 A fourth structural schematic diagram of the LED chip provided by the present invention;

[0057] Figure 5 A fifth structural schematic diagram of the LED chip provided by the present invention;

[0058] Figure 6 A sixth structural schematic diagram of the LED chip provided by the present invention;

[0059] Figure 7 A schematic diagram of a partial structure of an LED chip according to Example 1 provided by the present invention;

[0060] Figure 8 A schematic diagram of a partial structure of an LED chip according to Embodiment 2 of the present invention;

[0061] Fig. 9 A schematic diagram of a partial structure of an LED chip according to Embodiment 3 of the present invention;

[0062] Fig.10 A schematic diagram of a partial structure of an LED chip according to Embodiment 4 of the present invention;

[0063] Fig.11 A schematic diagram of a partial structure of an LED chip according to Embodiment 5 of the present invention;

[0064] Fig.12 A schematic diagram of the structure of a semiconductor light emitting element provided by the present invention;

[0065] Fig.13 This is a schematic diagram of the structure of the LED chip of Example 6 provided by the present invention.

[0066] Reference numerals:

[0067] 1-substrate; 2-first semiconductor layer; 3-light-emitting layer; 4-second semiconductor layer; 301-green light-emitting region; 3011-green light well layer; 3012-green light barrier layer; 302-blue light-emitting region; 3021-blue light well layer; 3022-blue light barrier layer; 303-supplementary light-emitting region; 3031-supplementary well layer; 304-fourth light-emitting region; 3041-fourth well layer; 3042-fourth barrier layer; 305-fifth light-emitting region; 306-red light-emitting region; 3061-red light well layer; 5-buffer layer; 6-stress release layer; 10-LED chip; 11-N electrode; 12-P electrode; 13-fluorescent film layer; 14-packaging layer; 101-epitaxial structure layer; 102-ITO layer; 103-reflective electrode. DETAILED DESCRIPTION

[0068] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0069] If there is no special explanation, in the present invention, "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "the first", "the second", "the third", "the fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0070] If there is no special explanation, the "include" and "comprising" mentioned in the present invention represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0071] If there is no special explanation, in the present invention, "one or more" or "at least one" refers to any one, any two or more of the listed items. Among them, "several" refers to any two or more of the listed items.

[0072] In a first aspect, the present invention provides an LED chip 10, such as Figure 1 As shown, it includes a substrate 1, a first semiconductor layer 2, a light-emitting layer 3 and a second semiconductor layer 4 stacked in sequence, wherein the light-emitting layer 3 includes a green light-emitting area 301, a blue light-emitting area 302 and a supplementary light-emitting area 303 arranged in sequence on the first semiconductor layer 2.

[0073] The LED chip 10 has a plurality of light-emitting layers 3 that can emit light of different colors.

[0074] In some specific embodiments, the green light emitting region 301 includes a green light well layer 3011 and a green light barrier layer 3012, the blue light emitting region 302 includes a blue light well layer 3021 and a blue light barrier layer 3022, and the supplementary light emitting region 303 includes a supplementary well layer 3031 and a supplementary barrier layer.

[0075] The In concentration of the supplementary hydrazine layer in the supplementary light emitting area 303 is ≥ the In concentration of the blue light hydrazine layer in the blue light emitting area 302 .

[0076] And / or, the thickness of the supplementary hydrazine layer in the supplementary light emitting area 303 is greater than the thickness of the blue light hydrazine layer in the blue light emitting area 302 .

[0077] In order to solve the problem of low luminous efficiency of existing multi-wavelength LED structures, the present invention makes a special design for the structure of the multi-quantum well light-emitting layer 3 to fully release stress and improve the recombination efficiency of the device.

[0078] By satisfying at least one of the above conditions (concentration relationship, thickness relationship), the supplementary light-emitting area 303 can fully release the stress between the light-emitting quantum well layer and the second semiconductor layer 4, thereby solving the problem of weak light-emitting intensity of the blue light-emitting area 302.

[0079] Specifically, the present invention grows a supplementary light-emitting zone 303 after the blue light-emitting zone 302. The well layer of the supplementary light-emitting zone 303 is thicker and has a lower energy barrier, which can pull the energy band of the entire light-emitting zone and change the distribution of carriers in the entire quantum well, so that the carrier distribution is closer to the second semiconductor layer 4. In addition, since the supplementary zone has a thicker hydrazine layer, it can buffer the mismatch stress generated by the second semiconductor layer 4 behind it, reduce the damage to the light-emitting zone caused by subsequent growth, and thus improve the brightness of the entire device; finally, the wavelength of the supplementary light is close to that of the blue light-emitting zone 302, which can enhance the intensity of the blue light-emitting zone 302.

[0080] In some specific embodiments, the wavelength range of the green light emitted by the green light emitting area 301 is 490nm~570nm, including but not limited to any point value of 490nm, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm or the range value between any two of them.

[0081] In some specific embodiments, the wavelength range of the blue light emitted by the blue light emitting area 302 is 410nm~480nm, including but not limited to any point value of 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm or the range value between any two of them.

[0082] In some specific embodiments, the wavelength range of the supplementary light emitted by the supplementary light-emitting area 303 is 410nm~480nm, including but not limited to any point value of 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm or the range value between any two of them.

[0083] Among them, the wavelength of blue light is close to the supplementary wavelength.

[0084] The main function of the supplementary light-emitting area 303 is to enhance the intensity of the light emitted by the blue light-emitting area 302 .

[0085] In some specific embodiments, the ratio of the thickness of the supplementary hydrazine layer in the supplementary light-emitting area 303 to the thickness of the blue light hydrazine layer in the blue light-emitting area 302 is 1~5:1, including but not limited to any point value of 1.1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 5:1 or a range value between any two of them; preferably 1.1~3.5:1.

[0086] In some specific implementations, the In concentration of the green light layer in the green light emitting area 301 is greater than the In concentration of the supplementary layer in the supplementary light emitting area 303, so as to ensure that the light emitted by the supplementary layer is not green light.

[0087] In some specific implementations, the thickness of the green light emitting layer in the green light emitting area 301 is greater than or equal to the thickness of the blue light emitting layer in the blue light emitting area 302, so as to ensure that the light emitted by the supplementary light emitting layer is not green light.

[0088] In some specific implementations, except for the different well layer thicknesses of the supplementary light emitting region 303 , the well layer thicknesses and barrier layer thicknesses of other light emitting regions may be the same, or the barrier layer thickness of the blue light emitting region 302 is the smallest.

[0089] In some specific embodiments, the green light emitting area 301 includes In x1 Ga 1-x1 The N green light well layer 3011 and the GaN-based green light barrier layer 3012 are alternately stacked and arranged in a periodic structure with a period number ≥ 1; wherein the period number includes but is not limited to any point value of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or a range value between any two. That is, the green light emitting area 301 includes an In x1 Ga 1-x1 N green light well layer 3011 and a GaN-based green light barrier layer 3012; or, the green light emitting region 301 includes In x1 Ga 1-x1 The N-based green light well layer 3011 and the GaN-based green light barrier layer 3012 are alternately stacked to form a periodic structure with a period number of ≥2.

[0090] In some specific embodiments, the blue light emitting area 302 includes In x2 Ga 1-x2A periodic structure in which the N blue light well layer 3021 and the GaN-based blue light barrier layer 3022 are alternately arranged with a period number ≥ 3; wherein the period number includes but is not limited to any point value of 3, 4, 5, 6, 7, 8, 9, 10 or a range value between any two of them.

[0091] Among them, the luminous intensity of the blue light luminescent area 302 is positively correlated with the period number of the blue light luminescent area 302 within a certain range, and the luminous intensity of the green light luminescent area 301 also follows the same rule with the luminous period number. By adjusting the period number of the periodic structure, the present invention can keep the intensities of the blue light luminescent area 302 and the green light luminescent area 301 within a certain proportional range.

[0092] In some specific implementations, the supplementary light emitting area 303 includes In x3 Ga 1-x3 The N supplementary well layer 3031 and the GaN-based supplementary barrier layer are alternately arranged with a period number ≥ 1, wherein the period number includes but is not limited to any point value of 2, 3, 4, 5, 6, 7, 8, 9, 10 or a range value between any two. That is, the supplementary light-emitting region 303 includes an In x3 Ga 1-x3 N supplementary well layer 3031 and a GaN-based supplementary barrier layer; or, the supplementary light-emitting region 303 includes In x3 Ga 1-x3 The N-based supplementary well layer 3031 and the GaN-based supplementary barrier layer are alternately stacked to form a periodic structure with a period number of ≥2.

[0093] Preferably, the number of the additional hydrazine layers in the additional light emitting area 303 is less than the number of the blue light hydrazine layers in the blue light emitting area 302. If the number of the additional hydrazine layers is greater than the number of the hydrazine layers in the blue light emitting area 302, the carriers in the blue light emitting area 302 will be transferred to the additional hydrazine layers to emit light, thereby making the blue light emitting area 302 meaningless.

[0094] In some specific embodiments, the In concentration of the green light well layer 3011 is greater than 3×10 20 Atoms / cm 3 .

[0095] In some specific implementations, see Figure 2 As shown, a fourth light emitting region 304 is further included between the green light emitting region 301 and the blue light emitting region 302, and the fourth light emitting region 304 includes a fourth well layer 3041 and a fourth barrier layer 3042. The fourth light emitting region 304 can make the light emitting spectrum of the entire device emit one more band of light to meet the needs of multi-band light emitting spectrum in future applications.

[0096] The In concentration of the green light emitting layer in the green light emitting area 301 is greater than the In concentration of the fourth well layer 3041 in the fourth light emitting area 304 and greater than the In concentration of the blue light emitting layer in the blue light emitting area 302, so as to ensure that the wavelengths emitted by the three light emitting areas are different.

[0097] Preferably, the fourth light emitting area 304 includes In x4 Ga 1-x4 A periodic structure in which the N fourth well layer 3041 and the GaN-based fourth barrier layer 3042 are alternately arranged with a period number ≥ 1; wherein the period number includes but is not limited to any point value of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or a range value between any two of them.

[0098] Preferably, the wavelength range of the blue light emitted by the fourth light-emitting area 304 is 440nm~480nm, including but not limited to any point value of 440nm, 450nm, 460nm, 470nm, 480nm or a range value between any two of them.

[0099] Preferably, the wavelength of the green light emitted by the green light emitting area 301 is greater than the wavelength of the blue light emitted by the fourth light emitting area 304 and greater than the wavelength of the supplementary light emitted by the supplementary light emitting area 303. This ensures that the number of cycles of the supplementary light emitting area 303 is minimal, because this layer is mainly used to reduce the stress caused by the lattice mismatch between the light emitting area and the subsequent growth of the second semiconductor layer 4, thereby improving the brightness of the overall device. If the wavelength of the supplementary light emitting area 303 is greater than that of the green light emitting area 301, the layer will become a green light emitting area 301, which will seriously affect the brightness of the blue light emitting area 302.

[0100] Preferably, the green light emitting zone 301, the fourth light emitting zone 304, the blue light emitting zone 302 and the supplementary light emitting zone 303 all include a periodic structure in which well layers and barrier layers are alternately arranged, and the period number of the blue light emitting zone 302 is ≥ the period number of the fourth light emitting zone 304 ≥ the period number of the green light emitting zone 301 ≥ the period number of the supplementary light emitting zone 303.

[0101] In some specific implementations, see Figure 3 As shown, a fifth light emitting region 305 is further included between the green light emitting region 301 and the fourth light emitting region 304, and the fifth light emitting region 305 includes a fourth well layer 3041 and a fifth barrier layer. The fifth light emitting region 305 can make the light emitting spectrum of the entire device emit one more band of light to meet the needs of multi-band light emitting spectrum in future applications.

[0102] The In concentration of the green light emitting layer in the green light emitting area 301 is greater than the In concentration of the fifth well layer in the fifth light emitting area 305, and the In concentration of the fourth well layer 3041 in the fourth light emitting area 304 is greater than the In concentration of the blue light emitting layer in the blue light emitting area 302. This ensures that the wavelengths emitted by the four light emitting areas are different.

[0103] In some specific implementations, the thickness of the green light hydrazine layer in the green light emitting area 301 is greater than or equal to the thickness of the fourth well layer 3041 in the fourth light emitting area 304 and greater than or equal to the thickness of the fifth well layer in the fifth light emitting area 305, so as to ensure that the wavelengths emitted by the four light emitting areas are different.

[0104] In some specific embodiments, the spectrum of the light-emitting element may include three or more light-emitting peaks, and the corresponding peak wavelengths of different light-emitting regions may be set according to the application.

[0105] In some specific implementations, see Figure 4 As shown, the light-emitting layer 3 also includes a red light-emitting area 306 arranged between the first semiconductor layer 2 and the green light-emitting area 301, and the light emitted by the red light-emitting area 306, the green light-emitting area 301, the blue light-emitting area 302 and the supplementary light-emitting area 303 are mixed to form white light.

[0106] Preferably, the wavelength range of the red light emitted by the red light emitting area 306 is 590nm~780nm, including but not limited to any point value of 590nm, 600nm, 620nm, 650nm, 680nm, 700nm, 730nm, 750nm, 760nm, 780nm or the range value between any two of them.

[0107] Preferably, the In concentration of the red light emitting layer in the red light emitting region 306 is greater than the In concentration of the green light emitting layer in the green light emitting region 301 .

[0108] Preferably, the number of red light emitting layers in the red light emitting area 306 is less than the number of blue light emitting layers in the blue light emitting area 302 .

[0109] Preferably, the sum of the number of red light hydrazine layers in the red light emitting area 306 and the number of green light hydrazine layers in the green light emitting area 301 is less than the number of blue light hydrazine layers in the blue light emitting area 302. The energy gaps of red light, green light, and blue light are arranged from small to large as red, green, and blue. The smaller the energy gap, the easier it is to accept carrier emission, that is, the stronger the luminescence ability. The smaller the energy gap, the fewer the number of periods of the luminescent area, which can ensure that the carrier distribution of the entire luminescent area is more uniform, and the intensity of the luminescent areas of different bands is also more uniform.

[0110] In some specific implementations, see Figure 5As shown, a buffer layer 5 is provided between the substrate 1 and the first semiconductor layer 2. The buffer layer 5 is mainly used to buffer the stress generated by the lattice mismatch between the substrate 1 and the GaN layer.

[0111] Preferably, the buffer layer 5 includes an AlN buffer layer 5 and / or a GaN buffer layer 5 .

[0112] Preferably, the GaN buffer layer 5 in the buffer layer 5 is one layer or multiple layers (more than two layers).

[0113] Preferably, the GaN buffer layer 5 in the buffer layer 5 is doped with Al element. The lattice of AlGaN is between the substrate 1 (Al 2 O 3 ) between the GaN layer, the AlGaN buffer layer 5 with Al added can release stress better than the GaN buffer layer 5.

[0114] In some specific implementations, see Figure 6 As shown, a stress release layer 6 is provided between the first semiconductor layer 2 and the green light emitting region 301. This layer is mainly used to release the stress generated by the lattice mismatch between the first semiconductor layer 2 (GaN material) and the green light emitting region 301 (InGaN material).

[0115] Preferably, the stress release layer 6 includes at least one GaN layer and / or at least one InGaN layer.

[0116] Preferably, the stress release layer 6 is doped with Si element and / or Al element.

[0117] In some specific embodiments, the LED chip 10 includes at least an epitaxial structure layer 101, and the epitaxial structure layer 101 includes at least a substrate 1, and a first semiconductor layer 2, a light-emitting layer 3 and a second semiconductor layer 4 sequentially arranged on the surface of the substrate 1, that is, the light-emitting layer 3 is located between the first semiconductor layer 2 and the second semiconductor layer 4.

[0118] In some specific implementations, the substrate 1 includes any substrate 1 commonly used in the art, such as a sapphire substrate 1, a GaN substrate 1, a silicon substrate 1 or a SiC silicon substrate 1, but is not limited thereto.

[0119] In some specific embodiments, the conductivity types of the first semiconductor layer 2 and the second semiconductor layer 4 are opposite, such as the first semiconductor layer 2 is an N-type layer, and the second semiconductor layer 4 is a P-type layer, and vice versa. For example, the first semiconductor layer 2 is an n-type doped GaN layer, and the second semiconductor layer 4 is a P-type doped GaN layer.

[0120] Further, the second semiconductor layer 4 may include a P-type AlGaN electron blocking layer and a Mg-doped P-type GaN layer.

[0121] In a second aspect, the present invention provides a method for preparing the LED chip 10 , comprising the following steps: sequentially growing a first semiconductor layer 2 , a green light emitting region 301 , a blue light emitting region 302 , a supplementary light emitting region 303 and a second semiconductor layer 4 on a substrate 1 .

[0122] In a third aspect, the present invention provides a semiconductor light emitting element, see Fig.12 A chip-scale packaged semiconductor light-emitting element shown includes the LED chip 10, having a top surface as a light-emitting surface, a bottom surface provided with an N electrode 11 and a P electrode 12, and a side surface connecting the top surface and the bottom surface;

[0123] A fluorescent film layer 13 at least covers the top surface of the LED chip 10;

[0124] The packaging layer 14 covers the periphery of the fluorescent film layer 13 and the periphery and lower surface of the LED chip 10 , and at least exposes the lower end surfaces of the N electrode 11 and the P electrode 12 .

[0125] The semiconductor light-emitting element provided by the present invention grows a supplementary light-emitting area 303 after the blue light-emitting area 302. The well layer of the supplementary light-emitting area 303 is thicker and has a lower energy barrier, which can pull the energy band of the entire light-emitting area and change the distribution of carriers in the entire quantum well, so that the carrier distribution is closer to the second semiconductor layer 4 side. In addition, since the supplementary area has a thicker hydrazine layer, it can buffer the mismatch stress generated by the second semiconductor layer 4 behind it, reduce the damage to the light-emitting area caused by subsequent growth, and thus improve the brightness of the entire device; finally, the wavelength of the supplementary light is close to that of the blue light-emitting area 302, which can enhance the intensity of the blue light-emitting area 302.

[0126] In some specific implementations, the fluorescent film layer 13 covers four sides of the LED chip 10 .

[0127] In some specific implementations, the fluorescent film layer 13 includes a silica gel layer containing fluorescent powder.

[0128] Preferably, the phosphor includes red phosphor.

[0129] The blue light and red light emitted by the LED chip 10 are at least partially converted into red light after passing through the fluorescent film layer 13 .

[0130] As the fluorescent film layer 13, (Ca, Sr, Ba)S:Eu can be used. 2+ 、(Ca、Sr、Ba) 2 Si 5 N8 :Eu 2+ and CaAlSiN 3 :Eu 2 + wait.

[0131] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0132] Example 1

[0133] like Figure 7 As shown, the LED chip 10 that emits blue and green dual-color light provided in this embodiment includes a substrate 1, a first semiconductor layer 2, a stress release layer 6, a light-emitting layer 3, and a second semiconductor layer 4 that are stacked in sequence, wherein the stress release layer 6 includes a three-layer structure composed of GaN / InGaN, and the light-emitting layer 3 includes a green light emitting area 301, a blue light emitting area 302, and a supplementary light emitting area 303 that are sequentially arranged on the first semiconductor layer 2. The green light emitting area 301 emits green light, the blue light emitting area 302 emits blue light, and the supplementary light emitting area 303 emits light of a supplementary wavelength, and the green light wavelength (535nm)>the supplementary wavelength (450nm)>the blue light wavelength (448nm). The green light emitting area 301 is InGaN. x1 Ga 1-x1 The N green light well layer 3011 and the GaN-based green light barrier layer 3012 are alternately stacked to form a periodic structure with a period number of 2. The In concentration of the green light well layer 3011 measured by Sims (secondary ion mass spectrometry) is greater than 3×10 20 Atoms / cm 3 The blue light emitting area 302 includes In x2 Ga 1-x2 The N-based blue light well layer 3021 and the GaN-based blue light barrier layer 3022 are alternately arranged in a periodic structure with a period number of 3. Sims measured the In concentration of the blue light well layer 3021 to be greater than 3×10 20 Atoms / cm 3 The additional light emitting area 303 includes an In x3 Ga 1-x3 N supplementary well layer 3031 and a GaN-based supplementary barrier layer. Sims measured the In concentration of the supplementary well layer 3031 to be greater than 3×10 20 Atoms / cm 3 The total thickness of each green light well layer 3011 , the total thickness of each blue light well layer 3021 and the thickness of the supplementary well layer 3031 are the same.

[0134] In this embodiment, the In concentration of the green light well layer 3011 is greater than the In concentration of the supplementary light emitting layer and greater than the In concentration of the blue light emitting layer. By growing the supplementary light emitting region 303 after the blue light emitting region 302, the supplementary light emitting region 303 has a higher In content, which can change the distribution of carriers in the entire quantum well, making the carrier distribution closer to the second semiconductor side, that is, easier to enter the blue light emitting region 302, thereby improving the intensity of the blue light emitting region 302.

[0135] Example 2

[0136] The luminous spectrum of the LED chip 10 that simultaneously emits blue and green dual-color light provided in this embodiment has at least three luminous peaks, see Figure 8 As shown, the difference between this embodiment and embodiment 1 is that a fourth light emitting area 304 (the second blue light emitting area 302) is included between the green light emitting area 301 and the blue light emitting area 302, and the fourth light emitting area 304 is In x4 Ga 1-x4 The N fourth well layer 3041 and the GaN-based fourth barrier layer 3042 are alternately stacked to form a periodic structure with a period number of 3. Sims measured the In concentration of the fourth well layer 3041 to be greater than 3×10 20 Atoms / cm 3 That is, the In concentration of the green light emitting layer is greater than the In concentration of the fourth well layer 3041 and the In concentration of the blue light emitting layer. The wavelength range of the blue light emitted by the fourth light emitting zone 304 is 460nm. The wavelength of the green light emitted by the green light emitting zone 301 is greater than the wavelength range of the blue light emitted by the fourth light emitting zone 304 and the wavelength of the supplementary light emitted by the supplementary light emitting zone 303.

[0137] Example 3

[0138] See also Fig. 9 As shown, the difference between this embodiment and embodiment 1 is that the In concentration of the green light well layer 3011, the In concentration of the supplementary hydrazine layer and the In concentration of the blue light well layer are the same, but the thickness of the supplementary hydrazine layer in this embodiment is t 3 (40Å)>thickness of blue light hydrazine layer t 2 (34Å), and the ratio of the thickness of the supplementary hydrazine layer to the thickness of the blue light hydrazine layer is 1.2:1, and the thickness of the green light hydrazine layer is t 1 >Thickness of blue light hydrazine layer t 2 (The thickness of each barrier layer in the light-emitting layer 3 is the same).

[0139] Example 4

[0140] See also Fig.10 As shown, the difference between this embodiment and embodiment 2 is that: the In concentration of the green light well layer 3011> the In concentration of the fourth well layer 3041 = the In concentration of the supplementary hydrazine layer> the In concentration of the blue light well layer, and the thickness of the supplementary hydrazine layer t 4 >Thickness of blue light hydrazine layer t3 , the thickness of green light well layer 3011 is t 1 >Thickness of the fourth well layer 3041 t 2 >Thickness of blue light hydrazine layer t 3 (The thickness of each barrier layer in the light-emitting layer 3 is the same).

[0141] Example 5

[0142] like Fig.11 As shown, the white light emitting LED chip 10 provided in this embodiment comprises a substrate 1, a first semiconductor layer 2, a light emitting layer 3, and a second semiconductor layer 4 which are stacked in sequence. The light emitting layer 3 comprises a red light emitting area 306, a green light emitting area 301, a blue light emitting area 302, and a supplementary light emitting area 303 which are sequentially arranged on the first semiconductor layer 2. The wavelength range of the red light emitted by the red light emitting area 306 is 590nm~780nm. The light emitted by the red light emitting area 306, the green light emitting area 301, the blue light emitting area 302, and the supplementary light emitting area 303 is mixed to form white light. The red light emitting area 306 is In x1 Ga 1-x1 The N red light well layer 3061 and the GaN-based red light barrier layer are alternately stacked to form a periodic structure with a period number of 2. The green light emitting region 301 is In x1 Ga 1-x1 The N green light well layer 3011 and the GaN-based green light barrier layer 3012 are alternately stacked to form a periodic structure with a period number of 2. The blue light emitting region 302 includes In x2 Ga 1-x2 The N-based blue light well layer 3021 and the GaN-based blue light barrier layer 3022 are alternately arranged in a periodic structure with a period number of 5. The supplementary light emitting region 303 is In x3 Ga 1-x3 The N supplementary well layer 3031 and the GaN-based supplementary barrier layer are alternately stacked to form a periodic structure with a period number of 3. Among them, the In concentration of the red light halogen layer is greater than the In concentration of the green light halogen layer, the In concentration of the supplementary halogen layer is greater than the In concentration of the blue light halogen layer, and the thickness of the supplementary halogen layer is greater than the thickness of the blue light halogen layer. The wavelength of the supplementary light emitted by the supplementary halogen layer is greater than the wavelength of the blue light emitted by the blue light emitting region 302.

[0143] Example 6

[0144] like Fig.13 As shown, the LED chip 10 provided in this embodiment is a flip chip, which includes: an epitaxial structure layer 101, the epitaxial structure layer 101 includes a first semiconductor layer 2, a light-emitting layer 3 and a second semiconductor layer 4 (the structure is the same as that of embodiment 1); an ITO layer 102 disposed on the second semiconductor layer 4, a reflective electrode 103, and an N electrode 11 and a P electrode 12 electrically connected to the first semiconductor layer 2 and the second semiconductor layer 4, respectively. The light emission spectrum of the LED chip 10 at least includes a blue light spectrum and a green light spectrum.

[0145] like Fig.12 As shown, the semiconductor light emitting element provided in this embodiment includes: the above-mentioned LED chip 10, having a top surface as a light emitting surface, a bottom surface provided with an N electrode 11 and a P electrode 12, and a side surface connecting the top surface and the bottom surface;

[0146] The fluorescent film layer 13 at least covers the top surface of the LED chip 10, and the fluorescent film covers the four side surfaces of the LED chip 10;

[0147] The encapsulation layer 14 covers the periphery of the fluorescent film layer 13 and the periphery and lower surface of the LED chip 10, and at least exposes the lower end surfaces of the N electrode 11 and the P electrode 12. The fluorescent film layer 13 is a silica gel layer containing fluorescent powder, and the fluorescent powder is a red fluorescent powder, which can output green light or blue light according to voltage or current. A part of the green light or a part of the blue light passes through the red light-emitting material (referring to the fluorescent powder that can excite red light), and another part of the green light or the blue light is converted into red light by the red light-emitting material. Therefore, the LED chip 10 is generally configured as a device that can independently and selectively emit three primary colors and a mixed color of the three primary colors in a single chip, wherein the adjustment method of adjusting the light intensity of each primary color may include: (a) controlling the input current intensity and duration and / or (b) controlling the thickness / concentration of the red light-emitting material. In this way, three primary colors with predetermined intensities can be achieved, for example, the intensities of the three primary colors are the same.

[0148] The blue light and red light emitted by the LED chip 10 are at least partially converted into red light after passing through the fluorescent film layer 13 .

[0149] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. An LED chip, characterized in that: It includes a substrate, a first semiconductor layer, a light-emitting layer and a second semiconductor layer, wherein the light-emitting layer includes a green light-emitting region, a blue light-emitting region and a supplementary light-emitting region sequentially arranged on the first semiconductor layer; The In concentration of the supplementary well layer in the supplementary light-emitting region is greater than the In concentration of the blue light well layer in the blue light-emitting region; and / or the thickness of the supplementary well layer in the supplementary light-emitting region is greater than the thickness of the blue light well layer in the blue light-emitting region, and the ratio of the thickness of the supplementary well layer in the supplementary light-emitting region to the thickness of the blue light well layer in the blue light-emitting region is 1.1 to 5:1; The wavelength range of the supplementary light emitted by the supplementary light-emitting area is between 410nm and 480nm.

2. The LED chip according to claim 1, characterized in that: At least one of the following conditions is met: (1) The wavelength range of the green light emitted by the green light emitting area is 490nm~570nm; (2) The wavelength range of the blue light emitted by the blue light emitting area is 410nm~480nm.

3. The LED chip according to claim 1, characterized in that: The In concentration of the green light well layer in the green light emitting region is greater than the In concentration of the supplementary well layer in the supplementary light emitting region; And / or, the thickness of the green light well layer in the green light emitting region is greater than or equal to the thickness of the blue light well layer in the blue light emitting region.

4. The LED chip according to claim 1, characterized in that: At least one of the following conditions is met: (1) The green light emitting region includes In x1 Ga 1-x1 A periodic structure in which N green light well layers and GaN-based green light barrier layers are alternately arranged and the period number is ≥1; (2) The blue light emitting area includes In x2 Ga 1-x2 A periodic structure in which N blue light well layers and GaN-based blue light barrier layers are alternately arranged and the period number is ≥3; (3) The supplementary light-emitting area includes In x3 Ga 1-x3 A periodic structure in which N-based supplementary well layers and GaN-based supplementary barrier layers are alternately arranged and the period number is ≥1; (4) The number of supplementary well layers in the supplementary light-emitting region is less than the number of blue light well layers in the blue light-emitting region.

5. The LED chip according to claim 1, characterized in that: A fourth light-emitting area is further included between the green light-emitting area and the blue light-emitting area, and satisfies at least one of the following conditions: (1) The In concentration of the green light well layer in the green light emitting region is greater than the In concentration of the fourth light well layer in the fourth light emitting region and greater than the In concentration of the blue light well layer in the blue light emitting region; (2) The fourth light-emitting region includes In x4 Ga 1-x4 A periodic structure in which the N fourth well layer and the GaN-based fourth barrier layer are alternately arranged and the period number is ≥1; (3) The wavelength range of the blue light emitted by the fourth light-emitting area is 440nm~480nm; (4) The wavelength of the green light emitted by the green light emitting area>the wavelength of the blue light emitted by the fourth light emitting area>the wavelength of the supplementary light emitted by the supplementary light emitting area; (5) The green light emitting zone, the fourth light emitting zone, the blue light emitting zone and the supplementary light emitting zone all include a periodic structure in which well layers and barrier layers are alternately arranged, and the period number of the blue light emitting zone ≥ the period number of the fourth light emitting zone ≥ the period number of the green light emitting zone ≥ the period number of the supplementary light emitting zone.

6. The LED chip according to claim 5, characterized in that: A fifth light-emitting zone is further included between the green light-emitting zone and the fourth light-emitting zone, and the In concentration of the green light well layer in the green light-emitting zone is greater than the In concentration of the fifth well layer in the fifth light-emitting zone, and the In concentration of the fourth well layer in the fourth light-emitting zone is greater than the In concentration of the blue light well layer in the blue light-emitting zone; And / or, the thickness of the green light well layer in the green light emitting region is ≥ the thickness of the fourth well layer in the fourth light emitting region is ≥ the thickness of the fifth well layer in the fifth light emitting region.

7. The LED chip according to claim 1, characterized in that: The light-emitting layer further includes a red light-emitting area disposed between the first semiconductor layer and the green light-emitting area, and the lights emitted by the red light-emitting area, the green light-emitting area, the blue light-emitting area and the supplementary light-emitting area are mixed to form white light; the red light-emitting area satisfies at least one of the following conditions: (1) The wavelength range of the red light emitted by the red light emitting area is 590nm~780nm; (2) The In concentration of the red light well layer in the red light emitting region is greater than the In concentration of the green light well layer in the green light emitting region; (3) The number of red light well layers in the red light emitting region is less than the number of blue light well layers in the blue light emitting region; (4) The sum of the number of red light well layers in the red light emitting region and the number of green light well layers in the green light emitting region is less than the number of blue light well layers in the blue light emitting region.

8. The LED chip according to claim 1, characterized in that: A buffer layer is disposed between the substrate and the first semiconductor layer, and the buffer layer includes an AlN buffer layer and / or a GaN buffer layer.

9. The LED chip according to claim 8, characterized in that: The GaN buffer layer is doped with Al element.

10. The LED chip according to claim 1, characterized in that: A stress release layer is provided between the first semiconductor layer and the green light emitting area, and the stress release layer satisfies at least one of the following conditions: (1) The stress release layer includes at least one GaN layer and / or at least one InGaN layer; (2) The stress release layer is doped with Si element and / or Al element.

11. The method for preparing an LED chip according to any one of claims 1 to 10, characterized in that: The method comprises the following steps: sequentially growing a first semiconductor layer, a green light emitting region, a blue light emitting region, a supplementary light emitting region and a second semiconductor layer on a substrate.

12. A semiconductor light emitting element, characterized in that: An LED chip according to any one of claims 1 to 10, comprising a top surface as a light emitting surface, a bottom surface provided with an N electrode and a P electrode, and a side surface connecting the top surface and the bottom surface; A fluorescent film layer, covering at least the top surface of the LED chip; The packaging layer covers the periphery of the fluorescent film layer and the periphery and lower surface of the LED chip, and at least exposes the lower end surfaces of the N electrode and the P electrode.

13. The semiconductor light emitting element according to claim 12, characterized in that: The fluorescent film layer covers four sides of the LED chip; And / or, the fluorescent film layer includes a silica gel layer containing fluorescent powder, and the fluorescent powder includes red fluorescent powder.

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