Semiconductor light-emitting element and preparation method thereof

Abstract

The present invention provides a semiconductor light-emitting element and a method for manufacturing the same. The semiconductor light-emitting element comprises, from bottom to top, a substrate, an n-type semiconductor layer, a first n-type intermediate layer, a second n-type intermediate layer, a quantum well layer, and a p-type semiconductor layer. The first n-type intermediate layer and the second n-type intermediate layer are doped with Si, and the concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is lower than the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer. The semiconductor light-emitting element provided by the present invention has high luminous efficiency and photoelectric conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor light-emitting element and a preparation method thereof. Background Art

[0002] Semiconductor light-emitting elements have the advantages of a wide adjustable wavelength range, high luminous efficiency, energy saving and environmental protection, long life, small size and strong designability. They have gradually replaced incandescent lamps and fluorescent lamps to become the light source for ordinary household lighting, and are widely used in new scenarios, such as Mini-LED, indoor high-resolution display screens, outdoor display screens, mobile phone backlights, TV backlights, laptop backlights, household lamps, street lights, car lights and flashlights.

[0003] However, traditional nitride semiconductor light-emitting devices are generally grown on sapphire substrates using heteroepitaxial growth. The lattice mismatch and thermal mismatch between sapphire and nitride semiconductors are large, resulting in a high defect density and polarization effect, which in turn causes non-radiative recombination and spatial separation of electron wave functions, reducing the luminous efficiency of the semiconductor light-emitting device. In addition, the hole ionization efficiency of traditional nitride semiconductor devices is much lower than the electron ionization efficiency, resulting in a hole concentration that is more than 1 to 2 orders of magnitude lower than the electron concentration. The excess electrons cannot participate in radiative recombination and overflow from the quantum well layer into the p-type semiconductor layer, resulting in non-radiative recombination. At the same time, the low hole ionization efficiency leads to a low hole concentration in the p-type semiconductor layer and difficulty in effectively injecting holes into the quantum well layer, resulting in low hole injection efficiency into the quantum well layer. Therefore, the above reasons lead to a large difference between the electron and hole concentrations in the quantum well layer, a low probability of electron and hole wave function overlap, and a low electron and hole recombination efficiency, which in turn leads to low luminous efficiency in the quantum well layer. Summary of the Invention

[0004] The object of the present invention is to provide a semiconductor light emitting element and a method for preparing the same, so as to solve the problem of low luminous efficiency of the semiconductor light emitting element.

[0005] In order to achieve the above-mentioned objectives and other related objectives, the present invention provides a semiconductor light-emitting element, comprising, from bottom to top, a substrate, an n-type semiconductor layer, a first n-type intermediate layer, a second n-type intermediate layer, a quantum well layer, and a p-type semiconductor layer, wherein the first n-type intermediate layer and the second n-type intermediate layer are doped with Si, and the concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is less than the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer.

[0006] Optionally, in the semiconductor light-emitting element, a concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer is a, and 5<a≤50.

[0007] Optionally, in the semiconductor light-emitting element, a concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is b, and 1≤b≤5.

[0008] Optionally, in the semiconductor light-emitting element, a concentration ratio of Si to unintentionally doped O in the second n-type intermediate layer is smaller than a concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer.

[0009] Optionally, in the semiconductor light-emitting element, a concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer is e, and 50<e≤200.

[0010] Optionally, in the semiconductor light-emitting element, a concentration ratio of Si to unintentionally doped O in the second n-type intermediate layer is f, and 10≤f≤50.

[0011] Optionally, in the semiconductor light-emitting element, the concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer is less than the concentration ratio of Si to unintentionally doped O in the n-type semiconductor layer, and the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer is less than the concentration ratio of Si to unintentionally doped C in the n-type semiconductor layer.

[0012] Optionally, in the semiconductor light-emitting element, the thickness of the first n-type intermediate layer is h, and 5nm≤h≤50nm.

[0013] Optionally, in the semiconductor light-emitting element, the thickness of the second n-type intermediate layer is k, and 20 nm ≤ k ≤ 100 nm.

[0014] Optionally, in the semiconductor light-emitting element, the semiconductor light-emitting element further includes a p-type intermediate layer, and the p-type intermediate layer is located between the quantum well layer and the p-type semiconductor layer.

[0015] Optionally, in the semiconductor light-emitting element, the p-type intermediate layer is doped with Mg, and a concentration ratio of Mg to H in the p-type intermediate layer is greater than a concentration ratio of Mg to H in the p-type semiconductor.

[0016] Optionally, in the semiconductor light-emitting element, a concentration ratio of Mg to H in the p-type intermediate layer is c, and 3≤c≤50.

[0017] Optionally, in the semiconductor light-emitting element, a concentration ratio of Mg to unintentionally doped O in the p-type intermediate layer is greater than a concentration ratio of Mg to unintentionally doped O in the p-type semiconductor.

[0018] Optionally, in the semiconductor light-emitting element, the concentration ratio d of Mg to unintentionally doped O in the p-type intermediate layer is 50≤d≤500.

[0019] Optionally, in the semiconductor light-emitting element, the thickness of the p-type intermediate layer is m, and 20nm≤m≤100nm.

[0020] Optionally, in the semiconductor light-emitting element, the material of the n-type semiconductor layer, the first n-type intermediate layer, the second n-type intermediate layer, the quantum well layer, the p-type intermediate layer and the p-type semiconductor layer includes at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN and AlInN.

[0021] In order to achieve the above-mentioned object and other related objects, the present invention further provides a method for preparing a semiconductor light-emitting element, comprising the following steps:

[0022] providing a substrate;

[0023] An n-type semiconductor layer, a first n-type intermediate layer, and a second n-type intermediate layer are sequentially formed on the substrate, wherein the first n-type intermediate layer and the second n-type intermediate layer are doped with Si, and a concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is smaller than a concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer;

[0024] A quantum well layer and a p-type semiconductor layer are sequentially formed on the second n-type intermediate layer.

[0025] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer is a, and 5<a≤50.

[0026] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is b, and 1≤b≤5.

[0027] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio of Si to unintentionally doped O in the second n-type intermediate layer is smaller than the concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer.

[0028] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer is e, and 50<e≤200.

[0029] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio of Si to unintentionally doped O in the second n-type intermediate layer is f, and 10≤f≤50.

[0030] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer is less than the concentration ratio of Si to unintentionally doped O in the n-type semiconductor layer, and the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer is less than the concentration ratio of Si to unintentionally doped C in the n-type semiconductor layer.

[0031] Optionally, in the method for preparing the semiconductor light-emitting element, the thickness of the first n-type intermediate layer is h, and 5nm≤h≤50nm.

[0032] Optionally, in the method for preparing the semiconductor light-emitting element, the thickness of the second n-type intermediate layer is k, and 20 nm ≤ k ≤ 100 nm.

[0033] Optionally, in the method for preparing the semiconductor light-emitting element, the method for preparing the semiconductor light-emitting element further includes: forming a p-type intermediate layer between the quantum well layer and the p-type semiconductor layer.

[0034] Optionally, in the method for preparing the semiconductor light-emitting element, the p-type intermediate layer is doped with Mg, and the concentration ratio of Mg to H in the p-type intermediate layer is greater than the concentration ratio of Mg to H in the p-type semiconductor.

[0035] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio of Mg to H in the p-type intermediate layer is c, and 3≤c≤50.

[0036] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio of Mg to unintentionally doped O in the p-type intermediate layer is greater than the concentration ratio of Mg to unintentionally doped O in the p-type semiconductor.

[0037] Optionally, in the method for preparing the semiconductor light-emitting element, the concentration ratio d of Mg to unintentionally doped O in the p-type intermediate layer is 50≤d≤500.

[0038] Optionally, in the method for preparing the semiconductor light-emitting element, the thickness of the p-type intermediate layer is m, and 20 nm ≤ m ≤ 100 nm.

[0039] Optionally, in the method for preparing the semiconductor light-emitting element, the material of the n-type semiconductor layer, the first n-type intermediate layer, the second n-type intermediate layer, the quantum well layer, the p-type intermediate layer and the p-type semiconductor layer includes at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN and AlInN.

[0040] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0041] The present invention adds a first n-type intermediate layer and a second n-type intermediate layer between the quantum well layer and the n-type semiconductor layer, and the concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is lower than the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer. Since the higher concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer can increase the merging and bending ratio of dislocations extending from the n-type semiconductor layer, a first n-type intermediate layer with a smooth surface can be grown, the size and density of V-type defects generated in the first n-type intermediate layer can be reduced, and the current spreading effect can be improved. The lower concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer can enhance the speed inconsistency in each growth direction, increase the V-type defects extending from the second n-type intermediate layer, and thus control the size of the V-type defects generated in the quantum well layer, improve the recombination efficiency of electrons and holes, and thus improve the luminous efficiency and photoelectric conversion efficiency of the semiconductor light-emitting element.

[0042] Moreover, the present invention can reduce the extension of dislocations by comprehensively regulating the thickness of the first n-type intermediate layer and the second n-type intermediate layer, the concentration ratio of Si to unintentionally doped C, and the concentration ratio of Si to unintentionally doped O, so that the leakage current (-10V) is less than 0.05μA and the ESD (HBM human body model -8kV) is greater than 80%. At the same time, the size of the V-type defects in the quantum well layer is made between 100nm and 500nm, thereby improving the quantum confinement effect of the quantum well, the carrier localization effect, and the hole injection efficiency of the V-type defect sidewall.

[0043] The present invention adds a p-type intermediate layer between the quantum well layer and the p-type semiconductor layer, and regulates the concentration ratio of Mg to H and the concentration ratio of Mg to unintentionally doped O in the p-type intermediate layer. This can reduce the proportion of Mg-H complexes and the proportion of Mg-O impurities, thereby reducing the formation energy of Mg, improving the solubility and ionization efficiency of Mg, and thus improving the hole injection efficiency of the quantum well, thereby improving the luminescence efficiency and photoelectric conversion efficiency.

[0044] The present invention adds a first n-type intermediate layer and a second n-type intermediate layer between the quantum well layer and the n-type semiconductor layer, and simultaneously adds a p-type intermediate layer between the quantum well layer and the p-type semiconductor layer. By comprehensively regulating the thickness of the first n-type intermediate layer and the second n-type intermediate layer, the concentration ratio of Si to unintentionally doped C, and the concentration ratio of Si to unintentionally doped O, as well as regulating the thickness of the p-type intermediate layer, the concentration ratio of Mg to H, and the concentration ratio of Mg to unintentionally doped O, the peak WPE (photoelectric conversion efficiency) of the semiconductor light-emitting element is greater than 60%, the leakage current (-10V) is less than 0.05uA, and the ESD (HBM human body model -8kV) is greater than 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic structural diagram of a semiconductor light emitting element according to an embodiment of the present invention;

[0046] Figure 2 is a secondary ion mass spectrum of a semiconductor light emitting device according to an embodiment of the present invention;

[0047] Figure 3 yes Figure 2 A partial enlarged view of the secondary ion mass spectrum in ;

[0048] Figure 4 is a flow chart of a method for preparing a semiconductor light-emitting element according to an embodiment of the present invention;

[0049] Figures 1 to 4 middle,

[0050] 11 - substrate, 12 - n-type semiconductor layer, 13 - first n-type intermediate layer, 14 - second n-type intermediate layer, 15 - quantum well layer, 16 - p-type intermediate layer, 17 - p-type semiconductor layer. DETAILED DESCRIPTION

[0051] The following is a further detailed description of the semiconductor light-emitting element and its preparation method proposed by the present invention, in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0052] See Figure 1 The present invention provides a semiconductor light-emitting element, which includes, from bottom to top, a substrate 11, an n-type semiconductor layer 12, a first n-type intermediate layer 13, a second n-type intermediate layer 14, a quantum well layer 15 and a p-type semiconductor layer 17.

[0053] In this embodiment, a first n-type intermediate layer 13 and a second n-type intermediate layer 14 are additionally provided between the n-type semiconductor layer 12 and the quantum well layer 15, and both the first n-type intermediate layer 13 and the second n-type intermediate layer 14 are doped with Si (silicon). Preferably, the concentration ratio of Si to unintentionally doped C (carbon) in the second n-type intermediate layer 14 is less than the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer 13.

[0054] Furthermore, the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer 13 is a, and preferably 5<a≤50. The concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer 14 is b, and preferably 1≤b≤5. This embodiment controls the size of the V-type defects generated in the first n-type intermediate layer and the second n-type intermediate layer by regulating the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer and the concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer, thereby regulating the size of the V-type defects generated in the quantum well layer, thereby helping to improve the recombination efficiency of electrons and holes, and thus improving the luminous efficiency of the semiconductor light-emitting element.

[0055] In this embodiment, the concentration ratio of Si to unintentionally doped O (oxygen) in the second n-type interlayer 14 is preferably lower than the concentration ratio of Si to unintentionally doped O in the first n-type interlayer 13. Furthermore, the concentration ratio of Si to unintentionally doped O in the first n-type interlayer 13 is e, and preferably 50<e≤200. The concentration ratio of Si to unintentionally doped O in the second n-type interlayer 14 is f, and preferably 10≤f≤50.

[0056] The thickness of the first n-type intermediate layer 13 is h, and preferably 5 nm ≤ h ≤ 50 nm. The thickness of the second n-type intermediate layer 14 is k, and preferably 20 nm ≤ k ≤ 100 nm.

[0057] This embodiment can reduce the extension of dislocations by regulating the thickness of the first n-type intermediate layer 13 and the second n-type intermediate layer 14, the concentration ratio of Si to unintentionally doped C, and the concentration ratio of Si to unintentionally doped O, so that the leakage current (-10V) is less than 0.05μA and the ESD (HBM human body model -8kV) is greater than 80%. At the same time, the size of the V-type defects in the quantum well layer is adjusted to be between 100nm and 500nm, thereby improving the quantum confinement effect of the quantum well, the carrier localization effect, and the hole injection efficiency of the V-type defect sidewall, thereby improving the electron and hole recombination efficiency, and thus improving the luminous efficiency of the semiconductor light-emitting element.

[0058] In other embodiments, a p-type intermediate layer 16 may be further included between the quantum well layer 15 and the p-type semiconductor layer 17. The p-type intermediate layer 16 is doped with Mg, and the concentration ratio of Mg to H in the p-type intermediate layer 16 is preferably greater than the concentration ratio of Mg to H in the p-type semiconductor 17. Furthermore, the concentration ratio of Mg to H in the p-type intermediate layer is c, and preferably 3≤c≤50.

[0059] The concentration ratio of Mg to unintentionally doped O in the p-type intermediate layer 16 is preferably greater than the concentration ratio of Mg to unintentionally doped O in the p-type semiconductor 17. Furthermore, the concentration ratio of Mg to unintentionally doped O in the p-type intermediate layer 16 is d, and is preferably 50 ≤ d ≤ 500. The thickness of the p-type intermediate layer 16 is m, and is preferably 20 nm ≤ m ≤ 100 nm.

[0060] This embodiment adds a first n-type intermediate layer and a second n-type intermediate layer between the quantum well layer and the n-type semiconductor layer, and adds a p-type intermediate layer between the quantum well layer and the p-type semiconductor layer. By regulating the thickness of the first n-type intermediate layer and the second n-type intermediate layer, the concentration ratio of Si to unintentionally doped C, and the concentration ratio of Si to unintentionally doped O, as well as regulating the thickness of the p-type intermediate layer, the concentration ratio of Mg to H, and the concentration ratio of Mg to unintentionally doped O, the peak WPE (photoelectric conversion efficiency) of the semiconductor light-emitting element is greater than 60%, the leakage current (-10V) is less than 0.05uA, and the ESD (HBM human body model -8kV) is greater than 80%.

[0061] See Figure 2 and Figure 3 The elemental composition of each structural layer of the semiconductor light-emitting element can be measured using SIMS (Secondary Ion Mass Spectrometry) analysis. For example, SIMS (Secondary Ion Mass Spectrometry) can be used to measure the concentrations of Si, O, and C in each of the first n-type intermediate layer and the second n-type intermediate layer. SIMS (Secondary Ion Mass Spectrometry) can also be used to measure the concentrations of Mg, H, and O in the p-type intermediate layer.

[0062] In this embodiment, the concentration of each component in each structural layer may be the average concentration of each component in each structural layer, or the peak concentration of each component in each structural layer. For example, the concentration of Si in the first n-type intermediate layer may be the average concentration of Si in the first n-type intermediate layer, or the peak concentration of Si in the first n-type intermediate layer.

[0063] See Figure 4 The method for preparing the semiconductor light emitting element comprises the following steps:

[0064] Step S1: providing a substrate 11;

[0065] Step S2: sequentially forming an n-type semiconductor layer 12, a first n-type intermediate layer 13, and a second n-type intermediate layer 14 on the substrate 11, wherein both the first n-type intermediate layer 13 and the second n-type intermediate layer 14 are doped with Si, and a concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer 14 is smaller than a concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer 13;

[0066] Step S3 : sequentially forming a quantum well layer 15 and a p-type semiconductor layer 17 on the second n-type intermediate layer 14 .

[0067] Execute step S1 to provide a substrate 11. As the substrate 11, it is preferred to use a substrate that can transmit the light emitted by the quantum well layer 15 and emit light from the substrate side, and for example, a sapphire substrate or a single crystal AlN substrate can be used. In addition, as the substrate 11, an AlN template substrate in which an undoped AlN structural layer is epitaxially grown on the surface of a sapphire substrate can also be used. In order to improve the light extraction efficiency, the light-emitting side of the substrate 11 or the opposite side thereof, or the surface of the AlN structural layer of the AlN template substrate can be a concave-convex shape. In order to reduce the dislocation of the AlN structural layer, a high-temperature (for example, above 1500°C) annealing treatment can also be performed.

[0068] A buffer layer may be provided between the substrate 11 and the n-type semiconductor layer 12 to alleviate the lattice mismatch between the substrate 11 and the n-type semiconductor layer 12. The material of the buffer layer is preferably AlN, but is not limited thereto.

[0069] Step S2 is performed to form an n-type semiconductor layer 12 , a first n-type intermediate layer 13 , and a second n-type intermediate layer 14 on the substrate 11 .

[0070] An n-type semiconductor layer 12 is formed on a substrate 11. The n-type semiconductor layer 12 is disposed on the substrate 11 via the buffer layer as needed, or the n-type semiconductor layer 12 can be directly disposed on the substrate 11. The n-type semiconductor layer 12 can be a conventional n-type layer, and its material can be at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN, and AlInN, but is not limited thereto.

[0071] For example, the n-type semiconductor layer 12 can be made of n-AlGaN. The n-type semiconductor layer 12 functions as an n-type layer by being doped with an n-type dopant. The n-type dopant is preferably, but not limited to, Si. Furthermore, the n-type semiconductor layer 12 can have a single-layer structure, a multi-layer structure, or a superlattice structure.

[0072] After the step of forming the n-type semiconductor layer 12 on the substrate 11, a first n-type intermediate layer 13 is formed on the n-type semiconductor layer 12. The first n-type intermediate layer 13 is doped with an n-type dopant, and the n-type dopant is preferably Si, but not limited thereto. Preferably, the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer 13 is less than the concentration ratio of Si to unintentionally doped C in the n-type semiconductor layer 12. Further, the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer 13 is a, and preferably 5<a≤50. In this embodiment, by setting a higher Si to unintentionally doped C concentration ratio in the first n-type intermediate layer 13, the merging and bending ratio of dislocations extending from the n-type semiconductor layer 12 can be improved, and the first n-type intermediate layer 13 with a smooth surface is grown, so that its surface roughness RMS (AFM test) is less than 2nm, and the size of the V-type defects generated in the layer can be controlled to be less than 50nm and the V-type defect density is less than 5E7cm -2 The inventors have found that when the size of the V-shaped defects generated in the quantum well layer is in the range of 100nm to 500nm, the quantum confinement effect, carrier localization effect, and hole injection efficiency of the V-shaped defect sidewalls of the quantum well layer are relatively high, so that the peak WPE of the semiconductor light-emitting element can be greater than 60%. However, if the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer 13 is too small, the crystal quality of the layer will deteriorate, which may eventually cause the size of the V-shaped defects generated in the quantum well layer to be greater than 500nm and the V-shaped defect density to be greater than 5E7cm -2 , affecting WPE; and the concentration ratio of Si to the unintentionally doped C in the first n-type intermediate layer 13 is too large, which may eventually lead to a V-shaped defect in the quantum well layer having a size of less than 100nm, affecting WPE.

[0073] In this embodiment, the concentration ratio of Si to unintentionally doped O in the first n-type interlayer 13 is preferably less than the concentration ratio of Si to unintentionally doped O in the n-type semiconductor layer 12. Furthermore, the concentration ratio of Si to unintentionally doped O in the first n-type interlayer 13 is e, and preferably 50<e≤200. If the concentration ratio of Si to unintentionally doped O in the first n-type interlayer 13 is too low, the resistance of the layer will increase, leading to an increase in voltage, and insufficient electrons will be injected into the quantum well layer, affecting WPE. If the concentration ratio of Si to unintentionally doped O in the first n-type interlayer 13 is too high, the lateral electron diffusion effect will be relatively poor, thereby reducing ESD capability.

[0074] The thickness of the first n-type intermediate layer 13 is h, and preferably 5nm≤h≤50nm. Within this thickness range, it can play a relatively excellent role in electron lateral expansion, which helps to improve ESD capability and can also improve the hole injection efficiency, thereby improving the luminous efficiency and WPE of the semiconductor light-emitting element. If the thickness of the first n-type intermediate layer 13 is too thick (for example, 100nm), the size of the V-shaped defects grown in the final quantum well layer may be less than 100nm, reducing the hole injection efficiency and causing a decrease in WPE. If the thickness of the first n-type intermediate layer 13 is too thin (for example, 1nm), it may not play a role in electron lateral expansion, the ESD capability will drop sharply, and it will not be sufficient to meet the dislocation merging and bending ratio, resulting in the size of the V-shaped defects in the final quantum well layer being greater than 500nm.

[0075] The material of the first n-type interlayer 13 can be at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN, and AlInN, but is not limited thereto. During the step of forming the first n-type interlayer 13 on the n-type semiconductor layer 12, the MO source and reaction gas used can be selected based on the material of the first n-type interlayer 13. For example, when the first n-type interlayer 13 is made of GaN, the MO source can be TMGa (trimethylgallium) and the reaction gas can be NH3. Because the first n-type interlayer 13 is also doped with an n-type dopant, such as Si, silane gas is introduced during the formation process of the first n-type interlayer 13 to achieve Si doping of the first n-type interlayer 13. The silane gas can be SiH4 or Si2H6, but is not limited thereto. The unintentional C doping in the first n-type interlayer 13 primarily originates from the MO source introduced during the formation process of the first n-type interlayer 13, while the unintentional O doping in the first n-type interlayer 13 primarily results from impure reaction raw materials.

[0076] After the step of forming the first n-type intermediate layer 13 on the n-type semiconductor layer 12, a second n-type intermediate layer 14 is formed on the first n-type intermediate layer 13. The second n-type intermediate layer 14 is doped with an n-type dopant, and the n-type dopant is preferably Si, but not limited thereto. Preferably, the concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer 14 is less than the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer 13. Furthermore, the concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer 14 is b, and preferably 1≤b≤5. This embodiment can enhance the speed inconsistency in each growth direction by setting a lower Si to C concentration ratio in the second n-type intermediate layer 14, increase the V-type defects extending from the first n-type intermediate layer 13, and control the size of the V-type defects generated in this layer to be between 50nm and 250nm.

[0077] Preferably, the concentration ratio of Si to unintentionally doped O in the second n-type interlayer 14 is less than the concentration ratio of Si to unintentionally doped O (oxygen) in the first n-type interlayer 13. Furthermore, the concentration ratio of Si to unintentionally doped O in the second n-type interlayer 14 is f, and preferably 10≤f≤50. If the concentration ratio of Si to unintentionally doped O in the second n-type interlayer 14 is too low, the resistance of the layer will increase, leading to an increase in voltage, and insufficient electrons will be injected into the quantum well layer, affecting WPE. If the concentration ratio of Si to unintentionally doped O in the second n-type interlayer 14 is too high, the lateral expansion of electrons will decrease, and the extension of dislocations will be blocked, resulting in a decrease in ESD capability and an increase in leakage.

[0078] The thickness of the second n-type intermediate layer 14 is k, and preferably 20nm≤k≤100nm, which can improve the crystal quality and also control the size of the V-shaped defects generated by the quantum well to improve the WPE. If the thickness of the second n-type intermediate layer 14 is too thick (for example, 150nm), the crystal quality of the layer may be deteriorated. The size of the V-shaped defects grown in the quantum well layer may be greater than 500nm and the density may be greater than 5E7cm -2 , resulting in a decrease in WPE; and if the thickness of the second n-type intermediate layer 14 is too thin (eg, 5 nm), the size of the V-type defects in the final quantum well layer may be less than 100 nm, resulting in a decrease in WPE.

[0079] The material of the second n-type interlayer 14 can be at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN, and AlInN, but is not limited thereto. During the step of forming the second n-type interlayer 14 on the first n-type interlayer 13, the MO source and reaction gas used can be selected based on the material of the second n-type interlayer 14. For example, when the second n-type interlayer 14 is made of GaN, the MO source is TMGa (trimethylgallium) and the reaction gas is NH3. Because the second n-type interlayer 14 is also doped with an n-type dopant, such as Si, silane gas is introduced during the formation process of the second n-type interlayer 14 to achieve Si doping of the second n-type interlayer 14. The silane gas can be SiH4 or Si2H6, but is not limited thereto. The unintentional C doping in the second n-type interlayer 14 primarily originates from the MO source introduced during the formation process of the second n-type interlayer 14, while the unintentional O doping in the second n-type interlayer 14 primarily results from impure reaction raw materials.

[0080] This embodiment can reduce the extension of dislocations, lower leakage current, and improve ESD by regulating the thickness of the first n-type intermediate layer 13 and the second n-type intermediate layer 14, the concentration ratio of Si to unintentionally doped C, and the concentration ratio of Si to unintentionally doped O. At the same time, the size of the V-shaped defects in the quantum well layer 15 is controlled to be between 100 nm and 500 nm, thereby enhancing the quantum confinement effect of the quantum well, the carrier localization effect, and the hole injection efficiency of the V-shaped defect sidewall, thereby improving WPE and luminous efficiency.

[0081] Step S3 is executed to sequentially form a quantum well layer 15 and a p-type semiconductor layer 17 on the second n-type intermediate layer 14 .

[0082] After forming the second n-type intermediate layer 14 on the first n-type intermediate layer 13, a quantum well layer 15 is formed on the second n-type intermediate layer 14. The material of the quantum well layer 15 can be at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN, and AlInN, but is not limited thereto.

[0083] The quantum well layer 15 is preferably composed of a multiple quantum well (MQW) structure formed by a well layer and a barrier layer. It should be noted that in the case of a multiple quantum well structure, the layer that emits light is the well layer. The quantum well layer 15 is an existing structure and will not be described in detail here.

[0084] After forming the quantum well layer 15 on the second n-type intermediate layer 14, a p-type semiconductor layer 17 is formed on the quantum well layer 15. The material of the p-type semiconductor layer 17 can be at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN, and AlInN, but is not limited thereto. For example, the material of the p-type semiconductor layer 17 is AlGaN. Examples of p-type dopants to be doped into the p-type semiconductor layer 17 include magnesium (Mg), zinc (Zn), calcium (Ca), beryllium (Be), and manganese (Mn), with Mg being generally used.

[0085] In other embodiments, after forming the quantum well layer 15 on the second n-type intermediate layer 14, a p-type intermediate layer 16 is first formed on the quantum well layer 15, and then a p-type semiconductor layer 17 is formed on the p-type intermediate layer 16. That is, a p-type intermediate layer 16 may be further included between the quantum well layer 15 and the p-type semiconductor layer 17.

[0086] The p-type interlayer 16 is doped with a p-type dopant, preferably Mg, but not limited thereto. Preferably, the concentration ratio of Mg to H in the p-type interlayer 16 is greater than the concentration ratio of Mg to H in the p-type semiconductor 17. This can reduce the proportion of Mg-H complexes, lower the formation energy of Mg, and increase the solubility and ionization efficiency of Mg, thereby improving the hole injection efficiency and luminescence efficiency of the quantum well. Furthermore, the concentration ratio of Mg to H in the p-type interlayer is c, and preferably 3≤c≤50.

[0087] Preferably, the concentration ratio of Mg to unintentionally doped O in the p-type interlayer 16 is greater than the concentration ratio of Mg to unintentionally doped O in the p-type semiconductor 17. This can reduce the ratio of Mg-O impurities, lower the formation energy of Mg, and increase the solubility and ionization efficiency of Mg, thereby improving the hole injection efficiency and luminescence efficiency of the quantum well. Furthermore, the concentration ratio d of Mg to unintentionally doped O in the p-type interlayer 16 is preferably 50 ≤ d ≤ 500. The thickness of the p-type interlayer 16 is m, preferably 20 nm ≤ m ≤ 100 nm.

[0088] The material of the p-type intermediate layer 16 can be at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN and AlInN, but is not limited thereto. In the step of forming the p-type intermediate layer 16 on the quantum well layer 15, the MO source and the reaction gas used can be selected according to the material of the p-type intermediate layer 16. For example, when the material of the p-type intermediate layer 16 is GaN, the MO source can be TEGa (triethylgallium) and the reaction gas can be NH3. Since the p-type intermediate layer 16 is also doped with a p-type dopant, such as Mg, MgCp2 is also introduced in the process of forming the p-type intermediate layer 16 to achieve Mg doping of the p-type intermediate layer 16. The H in the p-type intermediate layer 16 mainly comes from the H2 introduced in the process of forming the p-type intermediate layer 16, the MO source and the H in the reaction gas. The unintentional doping of O in the p-type intermediate layer 16 is mainly caused by the impurity of the reaction raw materials.

[0089] The present invention can detect the elemental composition of each structural layer of the semiconductor light-emitting element through secondary ion mass spectrometry (SIMS). For example, the Si, C, and O concentrations in the first n-type intermediate layer and the second n-type intermediate layer can be detected through SIMS. For another example, the Mg, H, and O concentrations in the p-type intermediate layer can be detected through SIMS. The present invention can also test the size and density of V-shaped defects through transmission electron microscopy (TEM).

[0090] The present invention can reduce dislocation extension, reduce leakage current, and improve ESD capability by comprehensively regulating the thickness of the first n-type intermediate layer, the Si to unintentionally doped C concentration ratio of the first n-type intermediate layer, the Si to unintentionally doped O concentration ratio of the first n-type intermediate layer, the thickness of the second n-type intermediate layer, the Si to unintentionally doped C concentration ratio of the second n-type intermediate layer, the Si to unintentionally doped O concentration ratio of the second n-type intermediate layer, the thickness of the p-type intermediate layer, the Mg to H concentration ratio of the p-type intermediate layer, and the Mg to unintentionally doped O concentration ratio of the p-type intermediate layer. In addition, the size of the V-type defects generated in the quantum well layer is regulated to improve the luminous efficiency and WPE of the semiconductor light-emitting element, so that the peak WPE of the semiconductor light-emitting element is greater than 60%, the leakage current (-10V) is less than 0.05uA, and the ESD (HBM human body model -8kV) is greater than 80%.

[0091] It should be noted that the above-mentioned semiconductor layer can be formed by well-known thin film formation methods such as metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), HVPE (Hydride Vapor Phase Epitaxy), plasma assisted chemical vapor deposition (PECVD), and sputtering. For example, the n-type semiconductor layer 12, the first n-type intermediate layer 13, the second n-type intermediate layer 14, the quantum well layer 15, the p-type intermediate layer 16, and the p-type semiconductor layer 17 can be formed by MOCVD.

[0092] In addition, it is understood that although the present invention has been disclosed above with reference to preferred embodiments, the above embodiments are not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or to modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of protection of the technical solution of the present invention.

[0093] It should also be understood that the present invention is not limited to the specific methods, compounds, materials, manufacturing techniques, uses, and applications described herein, which may vary. It should also be understood that the terminology described herein is used only to describe specific embodiments and is not intended to limit the scope of the present invention. It should be noted that the singular forms "a," "an," and "the" as used herein and in the appended claims include plural references unless the context clearly indicates otherwise. Thus, for example, a reference to "a step" means a reference to one or more steps, and may include secondary steps. All conjunctions used should be understood in their broadest sense. Thus, the word "or" should be understood to have the definition of a logical "or," not a logical "exclusive or," unless the context clearly indicates otherwise. Structures described herein are to be understood to also refer to functional equivalents of that structure. Language that can be interpreted as approximating should be so interpreted unless the context clearly indicates otherwise.

Claims

1. A semiconductor light emitting element, characterized in that: From bottom to top, the structure includes: a substrate, an n-type semiconductor layer, a first n-type intermediate layer, a second n-type intermediate layer, a quantum well layer, and a p-type semiconductor layer. The first n-type intermediate layer and the second n-type intermediate layer are doped with Si. The concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is less than the concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer. The concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer is less than the concentration ratio of Si to unintentionally doped O in the n-type semiconductor layer. The concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer is less than the concentration ratio of Si to unintentionally doped C in the n-type semiconductor layer. The concentration of each component in each structural layer is an average concentration or a peak concentration.

2. The semiconductor light emitting element according to claim 1, wherein The concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer is a, and 5<a≤50.

3. The semiconductor light emitting element according to claim 1, wherein The concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is b, and 1≤b≤5.

4. The semiconductor light emitting element according to claim 1, wherein A concentration ratio of Si to unintentionally doped O in the second n-type intermediate layer is smaller than a concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer.

5. The semiconductor light emitting element according to claim 4, wherein The concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer is e, and 50<e≤200.

6. The semiconductor light emitting element according to claim 4, wherein The concentration ratio of Si to unintentionally doped O in the second n-type intermediate layer is f, and 10≤f≤50.

7. The semiconductor light emitting element according to claim 1, wherein The thickness of the first n-type intermediate layer is h, and 5 nm ≤ h ≤ 50 nm.

8. The semiconductor light emitting element according to claim 1, wherein The thickness of the second n-type intermediate layer is k, and 20 nm ≤ k ≤ 100 nm.

9. The semiconductor light emitting element according to claim 1, wherein The semiconductor light emitting element further includes a p-type intermediate layer, and the p-type intermediate layer is located between the quantum well layer and the p-type semiconductor layer.

10. The semiconductor light emitting element according to claim 9, wherein The p-type intermediate layer is doped with Mg, and a concentration ratio of Mg to H in the p-type intermediate layer is greater than a concentration ratio of Mg to H in the p-type semiconductor.

11. The semiconductor light emitting element according to claim 10, wherein The concentration ratio of Mg to H in the p-type intermediate layer is c, and 3≤c≤50.

12. The semiconductor light emitting element according to claim 10, wherein A concentration ratio of Mg to unintentionally doped O in the p-type intermediate layer is greater than a concentration ratio of Mg to unintentionally doped O in the p-type semiconductor.

13. The semiconductor light emitting element according to claim 12, wherein: The concentration ratio d of Mg to unintentionally doped O in the p-type intermediate layer is 50≤d≤500.

14. The semiconductor light emitting element according to claim 9, wherein The thickness of the p-type intermediate layer is m, and 20 nm ≤ m ≤ 100 nm.

15. The semiconductor light emitting element according to claim 9, wherein The material of the n-type semiconductor layer, the first n-type intermediate layer, the second n-type intermediate layer, the quantum well layer, the p-type intermediate layer and the p-type semiconductor layer includes at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN and AlInN.

16. A method for preparing a semiconductor light-emitting element, characterized in that: The following steps are involved: providing a substrate; An n-type semiconductor layer, a first n-type intermediate layer, and a second n-type intermediate layer are sequentially formed on the substrate, wherein the first n-type intermediate layer and the second n-type intermediate layer are doped with Si, and a concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is less than a concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer, a concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer is less than a concentration ratio of Si to unintentionally doped O in the n-type semiconductor layer, and a concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer is less than a concentration ratio of Si to unintentionally doped C in the n-type semiconductor layer, and the concentration of each component in each structural layer is an average concentration or a peak concentration; A quantum well layer and a p-type semiconductor layer are sequentially formed on the second n-type intermediate layer.

17. The method for preparing a semiconductor light emitting element according to claim 16, wherein: The concentration ratio of Si to unintentionally doped C in the first n-type intermediate layer is a, and 5<a≤50.

18. The method for preparing a semiconductor light emitting element according to claim 16, wherein: The concentration ratio of Si to unintentionally doped C in the second n-type intermediate layer is b, and 1≤b≤5.

19. The method for preparing a semiconductor light emitting element according to claim 16, wherein: A concentration ratio of Si to unintentionally doped O in the second n-type intermediate layer is smaller than a concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer.

20. The method for preparing a semiconductor light emitting element according to claim 19, wherein: The concentration ratio of Si to unintentionally doped O in the first n-type intermediate layer is e, and 50<e≤200.

21. The method for preparing a semiconductor light emitting element according to claim 19, wherein: The concentration ratio of Si to unintentionally doped O in the second n-type intermediate layer is f, and 10≤f≤50.

22. The method for preparing a semiconductor light emitting element according to claim 16, wherein: The thickness of the first n-type intermediate layer is h, and 5 nm ≤ h ≤ 50 nm.

23. The method for preparing a semiconductor light emitting element according to claim 16, wherein: The thickness of the second n-type intermediate layer is k, and 20 nm ≤ k ≤ 100 nm.

24. The method for preparing a semiconductor light emitting element according to claim 16, wherein: The method for preparing the semiconductor light emitting element further includes: forming a p-type intermediate layer between the quantum well layer and the p-type semiconductor layer.

25. The method for preparing a semiconductor light emitting element according to claim 24, wherein: The p-type intermediate layer is doped with Mg, and a concentration ratio of Mg to H in the p-type intermediate layer is greater than a concentration ratio of Mg to H in the p-type semiconductor.

26. The method for preparing a semiconductor light emitting element according to claim 25, wherein: The concentration ratio of Mg to H in the p-type intermediate layer is c, and 3≤c≤50.

27. The method for preparing a semiconductor light emitting element according to claim 25, wherein: A concentration ratio of Mg to unintentionally doped O in the p-type intermediate layer is greater than a concentration ratio of Mg to unintentionally doped O in the p-type semiconductor.

28. The method for preparing a semiconductor light emitting element according to claim 27, wherein: The concentration ratio d of Mg to unintentionally doped O in the p-type intermediate layer is 50≤d≤500.

29. The method for preparing a semiconductor light emitting element according to claim 24, wherein: The thickness of the p-type intermediate layer is m, and 20 nm ≤ m ≤ 100 nm.

30. The method for preparing a semiconductor light emitting element according to claim 24, wherein: The material of the n-type semiconductor layer, the first n-type intermediate layer, the second n-type intermediate layer, the quantum well layer, the p-type intermediate layer and the p-type semiconductor layer includes at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN and AlInN.

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