Light emitting diode and light emitting device

Abstract

The invention relates to the technical field of semiconductor manufacturing, in particular to a light-emitting diode and a light-emitting device.The light-emitting diode comprises a semiconductor lamination layer, and the semiconductor lamination layer at least comprises an N-type semiconductor layer, an active layer, a hole injection layer and a P-type semiconductor layer which are stacked from bottom to top. The hole injection layer comprises a first concentration curve of Mg, the first concentration curve of Mg at least comprises a first peak shape close to the active layer and a second peak shape away from the active layer, and the maximum value of the first peak shape is not larger than the maximum value of the second peak shape. Therefore, more impurities can be prevented from diffusing into the active layer, the quality of the active layer is guaranteed, the radiative recombination efficiency of electrons and holes is improved, and the luminance of the light-emitting diode is further improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a light emitting diode and a light emitting device. Background Art

[0002] Light Emitting Diode (LED) is a semiconductor light-emitting element, usually made of semiconductors such as GaN, GaAs, GaP, GaAsP, etc., and its core is a PN junction with light-emitting characteristics. LED has the advantages of high luminous intensity, high efficiency, small size, and long service life, and is considered to be one of the most promising light sources at present. LED has been widely used in lighting, monitoring and command, high-definition broadcasting, high-end cinemas, office displays, conference interaction, virtual reality and other fields.

[0003] Light-emitting diodes usually include an N-type semiconductor layer, an active layer, a hole injection layer, and a P-type semiconductor layer. The hole injection layer (i.e., a low-temperature P-type layer) is the key layer that mainly provides hole injection. The setting of the hole injection layer affects the photoelectric performance of the light-emitting diode, especially the brightness. At present, the brightness of the light-emitting diode needs to be improved. Summary of the invention

[0004] The object of the present invention is to provide a light emitting diode and a light emitting device, which can effectively improve the light emitting brightness of the light emitting diode.

[0005] The present invention provides a light emitting diode, comprising a semiconductor stack, wherein the semiconductor stack comprises at least an N-type semiconductor layer, an active layer, a hole injection layer and a P-type semiconductor layer stacked from bottom to top, characterized in that the hole injection layer comprises a first concentration curve of Mg, the first concentration curve of Mg comprises at least a first peak close to the active layer and a second peak away from the active layer, wherein the maximum value of the first peak is not greater than the maximum value of the second peak.

[0006] The present invention further provides a light emitting device, which adopts the light emitting diode provided by any of the above embodiments.

[0007] A light-emitting diode and a light-emitting device provided by the present invention form at least two Mg-containing peaks in the hole injection layer by improving the hole injection layer, and the peak closest to the active layer is set to have a lower concentration, which can effectively reduce the impact on the active layer, avoid more impurities from diffusing into the active layer, ensure the quality of the active layer, and help improve the luminous brightness; while the peak far from the active layer is set to have a higher concentration, so as to increase the number of holes, improve the radiation recombination efficiency of electrons and holes, and thus improve the luminous brightness of the light-emitting diode.

[0008] Other features and beneficial effects of the present invention will be described in the following description, and some of the technical features and beneficial effects can be obviously derived from the description or understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, some of the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 It is a schematic structural diagram of a light emitting diode provided in the first embodiment of the present invention.

[0011] Figure 2 This is a secondary ion mass spectrometry (SIMS) analysis diagram of a local portion of a light-emitting diode provided by the first embodiment of the present invention.

[0012] Figure 3 It is a schematic structural diagram of the active layer of the light emitting diode provided by the first embodiment of the present invention.

[0013] Figure 4 yes Figure 2 A partial enlarged view of the secondary ion mass spectrometry (SIMS) analysis.

[0014] Figure 5 It is a schematic top view of a light emitting diode provided in the first embodiment of the present invention.

[0015] Figure 6 It is a schematic structural diagram of a light emitting diode provided in the second embodiment of the present invention.

[0016] Figure 7 This is a secondary ion mass spectrometry (SIMS) analysis diagram of a local portion of a light-emitting diode provided by the second embodiment of the present invention.

[0017] Figure 8 This is a secondary ion mass spectrometry (SIMS) analysis diagram of a local portion of a light-emitting diode provided by the third embodiment of the present invention.

[0018] Fig. 9 This is a secondary ion mass spectrometry (SIMS) analysis diagram of a local portion of a light-emitting diode provided by the fourth embodiment of the present invention.

[0019] Fig.10 It is a schematic structural diagram of an active layer of a light emitting diode provided in a fourth embodiment of the present invention.

[0020] Fig.11It is a schematic structural diagram of a light emitting device provided in the fifth embodiment of the present invention.

[0021] Reference numerals: 1. Light-emitting device; 11. Light-emitting diode; 12. Circuit substrate; 2. N-type semiconductor layer; 3. Active layer; 31. Well layer; 32. Barrier layer; 320. Last barrier layer; 4. Hole injection layer; 41. First injection layer; 42. Second injection layer; 5. P-type semiconductor layer; 6. Electron blocking layer; 7. Substrate; 81. N-electrode; 82. P-electrode.

[0022] N1, the first concentration curve of Mg; n1, the first peak shape; n2, the second peak shape; n3, the third peak shape; N2, the second concentration curve of Mg; n4, the fourth peak shape; N3, the concentration curve of In; n5, the fifth peak shape. DETAILED DESCRIPTION

[0023] The following describes the implementation of the present application through specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or operated through other different specific implementations, and the details in the present application can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application.

[0024] The composition of each layer included in the present application can be analyzed by any suitable method, such as secondary ion mass spectrometry (SIMS); the thickness of each layer can be analyzed by any suitable method, such as transmission electron microscopy (TEM) or scanning electron microscopy (SEM), to match the depth position of each layer on the SIMS map.

[0025] An embodiment of the present invention provides a light-emitting diode, which includes a semiconductor stack, the semiconductor stack includes at least an N-type semiconductor layer, an active layer, a hole injection layer and a P-type semiconductor layer stacked from bottom to top, the hole injection layer includes a first concentration curve of Mg, the first concentration curve of Mg includes at least a first peak shape close to the active layer and a second peak shape away from the active layer, wherein the maximum value of the first peak shape is not greater than the maximum value of the second peak shape. By regulating the Mg concentration in the hole injection layer, the portion close to the active layer has a lower concentration to avoid more impurities from diffusing into the active layer and ensure the quality of the active layer, and the portion away from the active layer has a higher concentration to increase the number of holes, improve the radiation recombination efficiency of electrons and holes, and thus improve the luminous brightness of the light-emitting diode.

[0026] In some embodiments, the maximum value of the first peak is 1E 19 ~1E 21 atoms / cm 3, the maximum value of the second peak is 1E 19 ~1E 21 atoms / cm 3 In an optional embodiment, the maximum value of the first peak is 1E 19 ~1E 20 atoms / cm3, which can better reduce the impact of impurities on the active layer and improve the quality of the active layer. In an optional embodiment, the maximum value of the second peak is 5E 19 ~5E 20 atoms / cm 3 , so as to obtain more holes and improve the hole-electron recombination efficiency.

[0027] In some embodiments, the maximum value of the second peak is not less than 1.5 times the maximum value of the first peak, so as to balance the effects of the number of holes and impurities on the active layer and obtain higher luminous brightness and lower voltage.

[0028] In some embodiments, the hole injection layer includes carbon impurities, and the concentration of the carbon impurities is not less than 3E 17 atoms / cm 3 , so as to facilitate the growth of the hole injection layer and avoid damage to the active layer.

[0029] In some embodiments, the hole injection layer is a semiconductor layer containing Al, wherein the Al concentration is 1E 19 ~3E 20 atoms / cm 3 , in order to increase the barrier height, increase the ability to confine electrons, and improve the crystal quality.

[0030] In some embodiments, the semiconductor stack further includes an electron blocking layer, which is located between the hole injection layer and the P-type semiconductor layer and is a semiconductor layer containing Al, wherein the Al concentration is not less than 1E 20 atoms / cm 3 By setting a higher Al concentration, it is beneficial to obtain a better effect of blocking electron overflow.

[0031] In some embodiments, the Al concentration in the electron blocking layer is greater than the Al concentration in the hole injection layer to avoid excessive Al concentration in the hole injection layer. The generated high potential barrier blocks electron overflow while avoiding affecting hole injection.

[0032] In some embodiments, the thickness of the hole injection layer is 30-70 nm. By appropriately reducing the thickness, the quality of the hole injection layer is guaranteed to take both brightness and ESD performance into consideration.

[0033] In some embodiments, the hole injection layer includes a first injection layer and a second injection layer located on the first injection layer, and the thickness of the first injection layer is not greater than the thickness of the second injection layer. In an optional embodiment, the thickness of the first injection layer is 10-30 nm, and the thickness of the second injection layer is 20-40 nm. In a preferred embodiment, the Mg concentration in the first injection layer is 1E 19 ~1E 20 atoms / cm 3 , which can better reduce the impact of impurities on the active layer and improve the quality of the active layer. In a preferred embodiment, the Mg concentration in the second injection layer is 5E 19 ~5E 20 atoms / cm3, thereby obtaining more holes and improving the hole-electron recombination efficiency.

[0034] In some embodiments, the first concentration curve of Mg further includes a third peak, the third peak is located between the first peak and the second peak, and the maximum value of the third peak is not less than the maximum value of the first peak. By adding the third peak, the number of holes can be further increased, and the radiation recombination efficiency of electrons and holes can be improved.

[0035] In some embodiments, the active layer is formed by repeatedly stacking a well layer and a barrier layer, wherein the barrier layer closest to the hole injection layer is the last barrier layer, the last barrier layer includes a second concentration curve of Mg, the second concentration curve of Mg includes a fourth peak, and the maximum value of the fourth peak is less than the maximum value of the first peak. In an optional embodiment, the maximum value of the fourth peak is 5E 18 ~3E 19 atoms / cm3, further increasing hole injection and significantly improving the brightness of the light-emitting diode.

[0036] In some embodiments, the light emitting diode radiates green light or blue light. The structure of the light emitting diode is more suitable for green light or blue light emitting diodes, especially display products, and has excellent improvement effect and significant improvement in luminous efficiency.

[0037] In some embodiments, the horizontal size of the light emitting diode is no more than 250 μm×300 μm, which can reduce the size of the light emitting diode while ensuring brightness and ESD performance, meet the market demand for small-size LEDs, and reduce production costs.

[0038] An embodiment of the present invention further provides a light emitting device, which uses a light emitting diode as described in any of the above embodiments to effectively improve the light emitting brightness and quality of the light emitting device.

[0039] The technical solution of the present invention will be clearly and completely described below through a variety of specific implementations in conjunction with the accompanying drawings in the embodiments of the present invention. Example 1

[0040] Figure 1 is a schematic diagram of the structure of a light emitting diode provided by the first embodiment of the present invention, Figure 2 is a secondary ion mass spectrometry (SIMS) analysis diagram of a local portion of a light emitting diode provided by the first embodiment of the present invention, Figure 3 is a schematic structural diagram of an active layer of a light emitting diode provided by a first embodiment of the present invention, Figure 4 yes Figure 2 A partial enlarged view of the secondary ion mass spectrometry (SIMS) analysis diagram, Figure 5 It is a schematic top view of a light emitting diode provided in the first embodiment of the present invention.

[0041] Reference Figures 1 to 5 The first embodiment of the present invention provides a light emitting diode 11, which includes at least one semiconductor stack. The semiconductor stack can be a structure that radiates light under any voltage, such as a gallium nitride-based or gallium arsenide-based material structure, which can be formed by metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), molecular beam epitaxy (MBE) and hydride vapor phase epitaxy (HVPE), but is not limited thereto. In this embodiment, a gallium nitride-based structure that provides green light is taken as an example for description.

[0042] In an optional embodiment, the light emitting diode 11 may further include a substrate 7 for supporting the semiconductor stack thereon. The substrate 7 may be made of a conductive material or an insulating material, and the material may be one of sapphire, silicon, silicon carbide, silicon oxide, zinc oxide, silicon nitride, and gallium nitride. Preferably, the substrate 7 is a sapphire substrate with a thickness of 400 to 1000 μm. The substrate 7 may be thinned or removed in subsequent processes, and no particular limitation is imposed herein.

[0043] For details, please refer to Figure 1 , the semiconductor stack includes at least an N-type semiconductor layer 2, an active layer 3, a hole injection layer 4 and a P-type semiconductor layer 5 stacked from bottom to top. In an optional embodiment, the N-type semiconductor layer 2 includes an N-type nitride layer, such as GaN, for providing electrons. The N-type nitride layer provides electrons by doping with n-type impurities, and the n-type impurities can be, for example, Si, Ge, Sn, Se and Te, preferably Si. The N-type semiconductor layer 2 can be a single-layer structure or a multi-layer structure, and it has a high doping concentration, which can reduce the contact resistance. In this embodiment, the thickness of the N-type semiconductor layer 2 is 1 to 4 μm, and the Si doping concentration is 1E 19 atoms / cm 3 ~1E 20 atoms / cm 3 between.

[0044] The active layer 3 is the region where electrons and holes recombine to provide light radiation. Different materials can be selected according to different luminescent wavelengths. The active layer 3 can be a single quantum well (Quantum Well, referred to as QW) composed of a barrier layer 32 and a well layer 31 or a periodic structure of multiple quantum wells (Multiple Quantum Well, referred to as MQW). Figure 3 , for example, it can be GaN / AlGaN, InAlGaN / InAlGaN, InGaN / AlGaN or InGaN / GaN. In this embodiment, the barrier layer 32 in the active layer 3 is GaN and / or AlGaN, and the well layer 31 is InGaN. By adjusting the composition ratio and thickness of the semiconductor material in the active layer 3, it is possible to obtain light radiating different wavelengths. Taking green light as an example, the wavelength radiated by the active layer 3 is 500-560nm. In an optional embodiment, the thickness of the active layer 3 is 50~210nm. Preferably, the number of periods of the active layer 3 is 5~12, wherein the thickness of the well layer 31 is 1~6nm, and the thickness of the barrier layer 32 is 7~20nm.

[0045] In an optional embodiment, the P-type semiconductor layer 5 includes a P-type nitride layer, such as GaN, for providing holes. The P-type nitride layer provides electrons by doping with p-type impurities, and the p-type impurities may be, for example, Mg, Zn, Ca, Sr, and Ba, preferably Mg. In the P-type semiconductor layer 5, a portion of the P-type semiconductor layer 5 away from the active layer 3 is highly doped, which is conducive to forming an ohmic contact. In this embodiment, the thickness of the P-type semiconductor layer 5 does not exceed 0.5 μm, and the Mg doping concentration is 6E 17 atoms / cm 3 ~8E 20 atoms / cm3.

[0046] The hole injection layer 4 is a structure that mainly provides holes for the active layer 3. The hole injection layer of the prior art usually increases the concentration of p-type doping (Mg) throughout the layer to increase the number of holes and thus improve the luminous efficiency. However, due to the increase in the Mg doping concentration, more Mg will diffuse into the active layer, resulting in an increase in impurities in the active layer 3, which in turn affects the quality of the active layer 3, resulting in a negative impact on luminescence.

[0047] Therefore, this embodiment regulates the Mg in the hole injection layer 4 to improve the above defects. Figure 2Specifically, the hole injection layer 4 includes a first concentration curve N1 of Mg, and the first concentration curve N1 of Mg includes two peaks, and the peak closer to the active layer 3 is defined as the first peak n1, and the peak farther away from the active layer 3 is defined as the second peak n2, and the maximum value (Mg concentration) of the first peak n1 is controlled not to be greater than the maximum value (Mg concentration) of the second peak n2. Preferably, the maximum value of the first peak n1 is less than the maximum value of the second peak n2, so that the lateral diffusion of carriers (holes) can be increased, which is beneficial to improving the luminous brightness and ESD antistatic performance. By setting the first peak n1 closest to the active layer 3 to have a lower Mg concentration, the impact on the active layer 3 can be effectively reduced, and more impurities can be prevented from diffusing into the active layer 3, thereby ensuring the quality of the active layer 3, and setting the peak away from the active layer 3 to have a higher concentration, so as to increase the number of holes and ensure the increase of the overall number of holes, thereby improving the radiation recombination efficiency of electrons and holes, and then improving the luminous brightness of the light-emitting diode. In addition, the high and low Mg peak shape design is conducive to the Mg in the second peak shape n2 close to the P-type semiconductor layer 5 to achieve Mg-H activation, while the Mg in the first peak shape n1 close to the active layer 3 is more difficult to effectively activate to break the Mg-H bond because it is farther away from the P-type semiconductor layer 5. Therefore, the first peak shape n1 with a lower Mg concentration can reduce resistance and thus obtain a lower forward voltage. It should be noted that all the peak shapes mentioned in the present invention can be axisymmetric or non-axisymmetric, which can be referred to Figure 2 .

[0048] More specifically, the maximum value of the first peak n1 is 1E 19 ~1E 21 atoms / cm 3 , the maximum value of the second peak n2 is 1E 19 ~1E 21 atoms / cm 3 Preferably, the maximum value of the first peak n1 is 1E 19 ~1E 20 atoms / cm 3 , which can better reduce the impact of impurities on the active layer 3 and improve the quality of the active layer 3. The maximum value of the second peak n2 is 5E 19 ~5E 20 atoms / cm 3 , thereby obtaining more holes and improving the hole-electron recombination efficiency. More preferably, the maximum value of the second peak shape n2 is not less than 1.5 times the maximum value of the first peak shape n1, so as to balance the influence of the number of holes and impurities on the active layer 3, and obtain higher luminous brightness and lower voltage.

[0049] In this embodiment, since the hole injection layer 4 is located on the active layer 3, the hole injection layer 4 needs to be grown at a low temperature to avoid damage to the underlying active layer 3 caused by high temperature growth, so that the hole injection layer 4 includes carbon impurities, and the concentration of the carbon impurities is not less than 3 E 17 atoms / cm 3 However, since the hole injection layer 4 is not grown at high temperature, the crystal quality of the layer is relatively poor (high carbon impurity concentration), which will affect the luminous efficiency. Therefore, in an optional embodiment, it can be improved by appropriately thinning the layer.

[0050] The thickness of the hole injection layer 4 is related to the luminous brightness, ESD antistatic performance and voltage. A hole injection layer 4 that is too thin cannot provide enough holes, and the path for impurities to enter the active layer 3 is shorter, making it easier for impurities to enter the active layer 3, which in turn leads to reduced brightness; while an overly thick hole injection layer 4 can increase the luminous brightness, but it will increase the Mg-H complex, resulting in an increase in the resistance of the hole injection layer 4 itself, which increases the forward voltage and is more likely to cause a flash point, affecting the ESD antistatic performance.

[0051] The hole injection layer 4 of this embodiment is suitable for all LED products, especially for LED products that radiate green light or blue light, for example, display screen LED products that radiate blue or green light. Since the size of display screen LED products is developing towards smaller sizes, their horizontal dimensions are usually not more than 250μm×300μm, and the requirements for brightness and ESD performance will be more stringent. Therefore, the hole injection layer 4 of the display screen LED product will have a greater thickness than the hole injection layer of other LED products to ensure a sufficient number of holes to increase the luminous brightness, and because of its large thickness, it will be easier to regulate Mg. However, as the thickness of the hole injection layer increases, the ESD performance will decrease accordingly. In order to take into account both brightness and ESD performance, the thickness of the hole injection layer 4 is appropriately thinned accordingly. Taking the green light display screen product as an example, the thickness of the hole injection layer 4 is preferably designed to be 30~70nm. It has been verified that the brightness of the light-emitting diode 11 of this embodiment is increased by 0.85%, the voltage is reduced by 0.005V, and the anti-static performance is significantly improved (ESD2K is increased by 0.24%, and ESD4K is increased by 10%), especially in the high-order voltage test.

[0052] In an alternative embodiment, the material of the hole injection layer 4 includes Al x In y Ga (1-x-y) N, where 0≤x≤1, 0≤y≤1. Preferably, the hole injection layer 4 is a semiconductor layer containing Al, such as AlGaN. By introducing Al into the hole injection layer 4, the height of the conduction band barrier can be increased, the electron confinement capability can be increased, and the crystal quality can be improved. It is further preferred that the Al concentration in the hole injection layer is 1E 19~3E 20 atoms / cm 3 .

[0053] In an optional embodiment, the semiconductor stack further includes an electron blocking layer 6 (EBL) for blocking electron overflow. The electron blocking layer 6 is located between the hole injection layer 4 and the P-type semiconductor layer 5, and the electron blocking layer 6 is a semiconductor layer containing Al. Specifically, the electron blocking layer 6 is a nitride layer containing Al, and its material may include at least one selected from the group consisting of AlInGaN, AlGaN and AlN, preferably AlGaN.

[0054] Furthermore, the Al content in the electron blocking layer 6 is above 60%, further, the Al content is between 60% and 100%, and further, it is controlled between 75% and 90%. A higher Al content in the electron blocking layer 6 is conducive to obtaining a better effect of blocking electron overflow. Specifically, the Al concentration of the electron blocking layer 6 is not less than 1E 20 atoms / cm 3 The thickness of the electron blocking layer 6 is 5 to 200 nm, and more preferably, the thickness of the electron blocking layer 6 is 5 to 100 nm to ensure sufficient blocking effect.

[0055] In an optional embodiment, when both the hole injection layer 4 and the electron blocking layer 6 are semiconductor layers containing Al, the Al concentration in the hole injection layer 4 needs to be less than the Al concentration in the electron blocking layer 6. Preferably, the Al concentration in the hole injection layer 4 is 1E 19 ~1E 20 atoms / cm 3 , to avoid excessive Al concentration, the high potential barrier generated will not only block the electron overflow, but also affect the injection of holes, thereby affecting the luminous brightness of the light-emitting diode 11.

[0056] In this embodiment, refer to Figure 4, the active layer 3 also includes an In concentration curve N3, which includes multiple In peaks, wherein the In peak closest to the first peak n1 is defined as the fifth peak n5. The distance D from the peak top (the location of the maximum value) of the first peak n1 to the peak top (the location of the maximum value) of the fifth peak n5 is set to be not less than 20nm, so as to ensure that the high concentration of Mg is at an appropriate distance from the active layer 3, and avoid the distance between the two being too close, thereby greatly reducing the probability of impurities entering the active layer. It should be noted that the peak area of ​​the In peak is where the well layer 31 of the active layer 3 is located, and the well layer 31 is the area where electrons and holes in the active layer 3 actually emit light by recombination, and because the migration rate of electrons is much higher than the migration rate of holes, the electron-hole recombination area will be more concentrated in the well layer 31 at the back of the active layer 3, especially in the well layer 31 where the fifth peak n5 is located. Therefore, by setting a larger distance D, the influence of high-concentration Mg impurities on the active layer 3 can be effectively avoided, the crystal quality of the active layer 3 can be greatly improved, and the luminous brightness of the light-emitting diode can be improved.

[0057] Reference Figure 5 The light emitting diode further includes an N electrode 81 and a P electrode 82, both of which are located on the semiconductor stack, and the N electrode 81 and the P electrode 82 are electrically connected to the N-type semiconductor layer 2 and the P-type semiconductor layer 5, respectively. Among them, the N electrode 81 and the P electrode 82 can be formed by stacking one or more electrode layers of metals such as chromium, nickel, aluminum, titanium, platinum, gold, palladium, and silver. The specific process of making electrodes and chips is well known to those skilled in the art, and the present invention will not be repeated here. Example 2

[0058] Reference Figure 6 and Figure 7 , Figure 6 is a schematic diagram of the structure of a light emitting diode provided by a second embodiment of the present invention, Figure 7 This is a secondary ion mass spectrometry (SIMS) analysis diagram of a part of the light-emitting diode provided by the second embodiment of the present invention. Compared with the light-emitting diode of the first embodiment of the present invention, the light-emitting diode of the second embodiment is different mainly in that the hole injection layer 4 includes a first injection layer 41 and a second injection layer 42, wherein the second injection layer 42 is located on the first injection layer 41, and the first injection layer 41 is closer to the active layer 3.

[0059] Specifically, the first injection layer 41 and the second injection layer 42 both contain Mg, wherein the Mg concentration in the first injection layer 41 is 1E 19 ~1E 21 atoms / cm 3 , the Mg concentration in the second injection layer 42 is 1E 19 ~1E 21 atoms / cm 3. Preferably, the Mg concentration in the second injection layer 42 is greater than the Mg concentration in the first injection layer 41, so as to increase the lateral diffusion of carriers (holes), which is beneficial to improving the luminous brightness and ESD antistatic performance. In addition, the high and low Mg concentration design is beneficial to the second injection layer 42 close to the P-type semiconductor layer 5 to achieve Mg-H activation, while the first injection layer 41 close to the active layer 3 is more difficult to be effectively activated to break the Mg-H bond because it is farther away from the P-type semiconductor layer 5. A lower Mg concentration will reduce the resistance, thereby having a lower forward voltage.

[0060] More specifically, the Mg concentration in the first injection layer 41 is 1E 19 ~1E 20 atoms / cm 3 , which can better reduce the influence of impurities on the active layer 3 and improve the quality of the active layer 3. The Mg concentration in the second injection layer 42 is 5E 19 ~5E 20 atoms / cm 3 , thereby obtaining more holes and improving the hole-electron recombination efficiency. Further preferably, the Mg concentration in the second injection layer 42 is not less than 1.5 times the Mg concentration in the first injection layer 41, so as to balance the influence of the number of holes and impurities on the active layer 3 and obtain higher luminous brightness. It should be noted that the Mg concentrations in the first injection layer 41 and the second injection layer 42 in this embodiment correspond to the Mg concentrations of the first peak shape n1 and the second peak shape n2 in the first embodiment, respectively.

[0061] In this embodiment, the thickness of the first injection layer 41 is not greater than the thickness of the second injection layer 42, so as to block impurities while ensuring a sufficient number of holes. Preferably, the thickness of the first injection layer 41 is 10-30 nm, and the thickness of the second injection layer 42 is 20-40 nm. Example 3

[0062] Reference Figure 8 , Figure 8 This is a secondary ion mass spectrometry (SIMS) analysis diagram of a part of a light-emitting diode provided by the third embodiment of the present invention. Compared with the light-emitting diodes of the first and second embodiments of the present invention, the light-emitting diode of the third embodiment is different mainly in that the first concentration curve N1 of Mg in the hole injection layer 4 also includes a third peak n3, the third peak n3 is located between the first peak n1 and the second peak n2, and the maximum value of the third peak n3 is not less than the maximum value of the first peak n1.

[0063] By adding the third peak n3, the number of holes can be further increased, and the radiation recombination efficiency of electrons and holes can be improved. The maximum value of the third peak n3 is 1E 19 ~1E 21 atoms / cm3 Preferably, the maximum value of the third peak shape n3 is greater than the maximum value of the first peak shape n1, and the size relationship between the second peak shape n2 and the third peak shape n3 is not particularly limited. In an optional embodiment, the maximum value of the second peak shape n2 is greater than the maximum value of the third peak shape n3, so that the transition of Mg in the second peak shape n2 to Mg in the first peak shape n1 is smoother, and the luminous efficiency is higher.

[0064] In other embodiments, the first concentration curve N1 of Mg in the hole injection layer 4 is not limited to only three, but may also include four, five, six, or other integer peaks. There is no particular limitation on the magnitude relationship between the maximum values ​​(Mg concentrations) of the peaks, and it is only necessary to ensure that the maximum value of the peak closest to the active layer 3 is the smallest. Example 4

[0065] Reference Fig. 9 and 10 , Fig. 9 is a secondary ion mass spectrometry (SIMS) analysis diagram of a local portion of a light emitting diode provided by the fourth embodiment of the present invention, Fig.10 : is a schematic diagram of the structure of the active layer of the light emitting diode provided by the fourth embodiment of the present invention. Compared with the light emitting diodes of the first, second and third embodiments of the present invention, the light emitting diode of the fourth embodiment is different mainly in that: the active layer 3 is a multi-quantum well structure (MQW) formed by repeatedly stacking the well layer 31 and the barrier layer 32, wherein the barrier layer 32 closest to the hole injection layer 4 is the last barrier layer 320, and the last barrier layer 320 includes the second concentration curve N2 of Mg.

[0066] Furthermore, the second Mg concentration curve N2 includes a fourth peak shape n4, the maximum value of the fourth peak shape n4 is less than the maximum value of the first peak shape n1, and preferably the maximum value of the fourth peak shape n4 is 5E 18 ~3E 19 atoms / cm 3 . By adding appropriate Mg doping in the last barrier layer 320, hole injection can be increased, the luminance of the light-emitting diode 11 can be further improved, and a certain electron blocking effect can be achieved. At the same time, the last barrier layer 320 can also be an Al-containing semiconductor layer, such as AlGaN. By increasing the Al component, the energy band can be improved to further obtain a better electron blocking effect. Since Al blocks holes while blocking electrons, the Al concentration in the last barrier layer 320 is set to be lower than the Al concentration in the electron blocking layer 6 to avoid excessive Al concentration, which is beneficial to hole injection into the active layer 3 and ensures the luminous efficiency of the light-emitting diode 11. Preferably, the Al concentration in the last barrier layer 320 is 1E 19 ~3E 20 atoms / cm 3More preferably, the Al concentration in the final barrier layer 320 is greater than the Al concentration in the hole injection layer 4, thereby improving the barrier effect on impurities.

[0067] In an alternative embodiment, continue to refer to Fig.10 , the last barrier layer 320 has a greater thickness, which is greater than the thickness of a single barrier layer 32 in the active layer 3. Preferably, the thickness of the last barrier layer 320 ranges from 9 to 20 nm. On the one hand, it is beneficial to reduce electron overflow and increase the probability of radiation recombination. On the other hand, it can block the diffusion of upper impurities into the active layer 3 to avoid contaminating the active layer 3, thereby improving the quality of the active layer 3 and the radiation recombination efficiency, thereby improving the luminous brightness of the light-emitting diode 11. It has been verified that the brightness of the light-emitting diode 11 of this embodiment is increased by 1.2%, the voltage is reduced by 0.008V, and the anti-static performance is significantly improved (ESD2K is increased by 0.3%, and ESD4K is increased by 12%), especially in high-order voltage testing. Example 5

[0068] The fifth embodiment of the present invention further provides a light emitting device 1, which includes a light emitting diode 11 provided in any of the above embodiments. The light emitting diode 11 can be arranged on a circuit substrate 12. Fig.11 The light emitting device 1 may be, for example, a white light illumination device, a backlight display device, an RGB display device, a car light, a flash light, a projection light, a stage light, etc. The light emitting device has the characteristics of higher light extraction efficiency and anti-static performance (ESD).

[0069] In summary, a light-emitting diode and a light-emitting device provided by the present invention improve the hole injection layer 4 so that at least two Mg-containing peaks are formed in the hole injection layer 4, and the peak closest to the active layer 3 is set to have a lower concentration, which can effectively reduce the impact on the active layer 3, avoid more impurities from diffusing into the active layer 3, ensure the quality of the active layer 3, and help improve the luminous brightness. The peak far away from the active layer 3 is set to have a higher concentration, which is used to increase the number of holes and improve the radiation recombination efficiency of electrons and holes, thereby improving the luminous brightness of the light-emitting diode 11.

[0070] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A light emitting diode, comprising a semiconductor stack, wherein the semiconductor stack comprises at least an N-type semiconductor layer, an active layer, a hole injection layer and a P-type semiconductor layer stacked from bottom to top, characterized in that: The hole injection layer includes a first concentration curve of Mg, and the first concentration curve of Mg includes at least a first peak close to the active layer and a second peak away from the active layer, wherein the maximum value of the first peak is not greater than the maximum value of the second peak.

2. The light emitting diode according to claim 1, characterized in that: The maximum value of the first peak is 1E 19 ~1E 21 atoms / cm 3 The maximum value of the second peak is 1E 19 ~1E 21 atoms / cm 3 .

3. The light emitting diode according to claim 1, characterized in that: The maximum value of the first peak is 1E 19 ~1E 20 atoms / cm 3 .

4. The light emitting diode according to claim 1, characterized in that: The maximum value of the second peak is 5E 19 ~5E 20 atoms / cm 3 .

5. The light emitting diode according to claim 1, characterized in that: The maximum value of the second peak shape is not less than 1.5 times the maximum value of the first peak shape.

6. The light emitting diode according to claim 1, characterized in that: The hole injection layer includes carbon impurities, the concentration of which is not less than 3 E 17 atoms / cm 3 .

7. The light emitting diode according to claim 1, characterized in that: The hole injection layer is a semiconductor layer containing Al, wherein the Al concentration is 1E 19 ~3E 20 atoms / cm 3 .

8. The light emitting diode according to claim 1 or 7, characterized in that: The semiconductor stack further comprises an electron blocking layer, which is located between the hole injection layer and the P-type semiconductor layer and is a semiconductor layer containing Al, wherein the Al concentration is not less than 1E 20 atoms / cm 3 .

9. The light emitting diode according to claim 8, characterized in that: The Al concentration in the electron blocking layer is greater than the Al concentration in the hole injection layer.

10. The light emitting diode according to claim 1, characterized in that: The thickness of the hole injection layer is 30-70 nm. 11 . The light emitting diode according to claim 1 , further characterized in that the hole injection layer comprises a first injection layer and a second injection layer located on the first injection layer, and the thickness of the first injection layer is not greater than the thickness of the second injection layer.

12. The light emitting diode according to claim 11, characterized in that: The thickness of the first injection layer is 10-30 nm, and the thickness of the second injection layer is 20-40 nm.

13. The light emitting diode according to claim 11, characterized in that: The Mg concentration in the first injection layer is 1E 19 ~1E 20 atoms / cm 3 .

14. The light emitting diode according to claim 11, characterized in that: The Mg concentration in the second injection layer is 5E 19 ~5E 20 atoms / cm 3 .

15. The light emitting diode according to claim 1, characterized in that: The first Mg concentration curve further includes a third peak shape, the third peak shape is located between the first peak shape and the second peak shape, and the maximum value of the third peak shape is not less than the maximum value of the first peak shape.

16. The light emitting diode according to claim 1, characterized in that: The active layer is formed by repeatedly stacking a well layer and a barrier layer, wherein the barrier layer closest to the hole injection layer is the last barrier layer, the last barrier layer includes a second concentration curve of Mg, the second concentration curve of Mg includes a fourth peak, and the maximum value of the fourth peak is less than the maximum value of the first peak.

17. The light emitting diode according to claim 1, characterized in that: The maximum value of the fourth peak is 5E 18 ~3E 19 atoms / cm 3 .

18. The light emitting diode according to claim 1, characterized in that: The light emitting diode radiates green light or blue light.

19. The light emitting diode according to claim 1, characterized in that: The horizontal size of the light emitting diode is no greater than 250 μm×300 μm.

20. A light emitting device, characterized in that: The light emitting device adopts the light emitting diode according to any one of claims 1 to 19.

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