Light emitting diode and method of manufacturing the same

Abstract

The application provides a light emitting diode and a manufacturing method thereof, the light emitting diode comprising a substrate from bottom to top, an n-type semiconductor layer, a quantum well layer, a hole injection layer and a p-type semiconductor layer, the hole injection layer comprising a p-type doped element and an n-type unintentionally doped element, and a ratio a of a concentration of the p-type doped element to a concentration of the n-type unintentionally doped element is greater than or equal to 80. The technical scheme of the application significantly reduces the difference between electron and hole concentrations in the quantum well layer, and further significantly improves the photoelectric conversion efficiency of the light emitting diode.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a light-emitting diode and its manufacturing method. Background Technology

[0002] Semiconductor light-emitting diodes (LEDs) have advantages such as a wide adjustable wavelength range, high luminous efficiency, energy saving and environmental protection, long life, small size and strong design flexibility. They have gradually replaced incandescent lamps and fluorescent lamps, becoming the light source for ordinary household lighting, and are widely used in new scenarios such as Mini-LED, indoor high-resolution displays, outdoor displays, mobile phone backlights, TV backlights, laptop backlights, household lighting fixtures, streetlights, vehicle lights and flashlights.

[0003] However, in traditional light-emitting diodes (LEDs), the nitride semiconductor layer is typically formed by heteroepitaxial growth on a sapphire substrate. This nitride semiconductor layer includes, from bottom to top, an n-type semiconductor layer, a quantum well layer, and a p-type semiconductor layer. The large lattice and thermal mismatch between the sapphire substrate and the nitride semiconductor layer leads to high defect density and polarization effects, resulting in nonradiative recombination and spatial separation of the electron wavefunction, thus reducing the luminous efficiency of the semiconductor LED. Furthermore, the hole ionization efficiency of traditional nitride semiconductor layers is far lower than that of electron ionization, resulting in a hole concentration that is one to two orders of magnitude lower than the electron concentration. Excess electrons cannot participate in radiative recombination and instead overflow from the quantum well layer into the p-type semiconductor layer, causing nonradiative recombination. Simultaneously, the low hole ionization efficiency leads to a low hole concentration in the p-type semiconductor layer, making it difficult to effectively inject holes into the quantum well layer, resulting in low efficiency of hole injection into the quantum well layer. Therefore, the large difference in electron and hole concentrations in the quantum well layer results in a low probability of overlap between electron and hole wave functions, leading to low recombination efficiency of electrons and holes in the quantum well layer. This, in turn, results in low luminous efficiency of the quantum well layer and consequently, low photoelectric conversion efficiency of the light-emitting diode.

[0004] Therefore, a light-emitting diode and its manufacturing method are provided to improve the photoelectric conversion efficiency of the light-emitting diode. Summary of the Invention

[0005] The purpose of this invention is to provide a light-emitting diode and its manufacturing method, which significantly reduces the difference in electron and hole concentrations in the quantum well layer, thereby significantly improving the photoelectric conversion efficiency of the light-emitting diode.

[0006] To achieve the above objectives, the present invention provides a light-emitting diode, comprising, from bottom to top, a substrate, an n-type semiconductor layer, a quantum well layer, a hole injection layer, and a p-type semiconductor layer, wherein the hole injection layer comprises a p-type dopant element and an n-type unintentional dopant element, and the ratio a of the concentration of the p-type dopant element to the concentration of the n-type unintentional dopant element is ≥80.

[0007] Optionally, the p-type dopant is magnesium, and the n-type unintentional dopant is silicon.

[0008] Optionally, the hole injection layer further includes carbon, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the carbon is b, where 10 ≤ b ≤ 800.

[0009] Optionally, the hole injection layer further includes oxygen, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the oxygen is c, where 15 ≤ c ≤ 800.

[0010] Optionally, the hole injection layer further includes hydrogen, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the hydrogen is d, where 1 ≤ d ≤ 50.

[0011] Optionally, the hole injection layer further comprises carbon and oxygen elements, wherein the ratio of the concentration of the p-type dopant magnesium element to the concentration of the carbon element is b, 10≤b≤800; and the ratio of the concentration of the p-type dopant magnesium element to the concentration of the oxygen element is c, 15≤c≤800.

[0012] Optionally, the hole injection layer further comprises carbon and hydrogen elements, wherein the ratio of the concentration of the p-type doped element magnesium to the concentration of the carbon element is b, 10≤b≤800; and the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, 1≤d≤50.

[0013] Optionally, the hole injection layer further includes oxygen and hydrogen elements, and the ratio of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is c, where 15 ≤ c ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, where 1 ≤ d ≤ 50.

[0014] Optionally, the hole injection layer further comprises carbon, oxygen, and hydrogen elements, wherein the ratio of the concentration of the p-type doped element magnesium to the concentration of the carbon element is b, 10 ≤ b ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is c, 15 ≤ c ≤ 800; and the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, 1 ≤ d ≤ 50.

[0015] Optionally, the thickness of the hole injection layer is 10 nm to 50 nm.

[0016] Optionally, the hole injection layer is made of Al. x In y Ga 1-x-y N, 0≤x≤1, 0≤y≤1.

[0017] Optionally, when 0 < x < 1 and 0 < y < 1, the ratio of Al to In signal intensities in the hole injection layer measured by the secondary ion mass spectrometer is 300 to 1E5.

[0018] Optionally, the hole concentration in the hole injection layer is greater than or equal to 5E17cm³. -3 .

[0019] The present invention also provides a method for manufacturing a light-emitting diode, comprising:

[0020] Provide a substrate;

[0021] An n-type semiconductor layer, a quantum well layer, a hole injection layer, and a p-type semiconductor layer are sequentially formed on the substrate. The hole injection layer contains p-type doped elements and n-type unintentional doped elements, and the ratio of the concentration of the p-type doped element to the concentration of the n-type unintentional doped element, a, is ≥ 80.

[0022] Optionally, the p-type dopant is magnesium, and the n-type unintentional dopant is silicon.

[0023] Optionally, the hole injection layer further includes carbon, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the carbon is b, where 10 ≤ b ≤ 800.

[0024] Optionally, the hole injection layer further includes oxygen, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the oxygen is c, where 15 ≤ c ≤ 800.

[0025] Optionally, the hole injection layer further includes hydrogen, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the hydrogen is d, where 1 ≤ d ≤ 50.

[0026] Optionally, the hole injection layer further comprises carbon and oxygen elements, wherein the ratio of the concentration of the p-type dopant magnesium element to the concentration of the carbon element is b, 10≤b≤800; and the ratio of the concentration of the p-type dopant magnesium element to the concentration of the oxygen element is c, 15≤c≤800.

[0027] Optionally, the hole injection layer further comprises carbon and hydrogen elements, wherein the ratio of the concentration of the p-type doped element magnesium to the concentration of the carbon element is b, 10≤b≤800; and the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, 1≤d≤50.

[0028] Optionally, the hole injection layer further includes oxygen and hydrogen elements, and the ratio of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is c, where 15 ≤ c ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, where 1 ≤ d ≤ 50.

[0029] Optionally, the hole injection layer further comprises carbon, oxygen, and hydrogen elements, wherein the ratio of the concentration of the p-type doped element magnesium to the concentration of the carbon element is b, 10 ≤ b ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is c, 15 ≤ c ≤ 800; and the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, 1 ≤ d ≤ 50.

[0030] Optionally, the thickness of the hole injection layer is 10 nm to 50 nm.

[0031] Optionally, the hole injection layer is made of Al. x In y Ga 1-x-y N, 0≤x≤1, 0≤y≤1.

[0032] Optionally, when 0 < x < 1 and 0 < y < 1, the ratio of Al to In signal intensities in the hole injection layer measured by the secondary ion mass spectrometer is 300 to 1E5.

[0033] Optionally, the hole concentration in the hole injection layer is greater than or equal to 5E17cm³. -3 .

[0034] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0035] The light-emitting diode and its manufacturing method of the present invention improve the solubility and ionization rate of magnesium by inserting a hole injection layer between a quantum well layer and a p-type semiconductor layer. This hole injection layer contains p-type dopant and n-type unintentional dopant elements, with the concentration of the p-type dopant element being greater than that of the n-type unintentional dopant element. Specifically, the ratio of the concentration of the p-type dopant element magnesium to the concentration of the n-type unintentional dopant element silicon is a≥80, the ratio of the concentration of the p-type dopant element magnesium to the concentration of carbon is 10≤b≤800, the ratio of the concentration of the p-type dopant element magnesium to the concentration of oxygen is 15≤c≤800, and the ratio of the concentration of the p-type dopant element magnesium to the concentration of hydrogen is 1≤d≤50. This increases the hole concentration in the hole injection layer (to 5E17 cm⁻¹). -3 (as described above), thereby significantly reducing the difference in electron and hole concentrations in the quantum well layer, which in turn significantly improves the photoelectric conversion efficiency of the light-emitting diode (the photoelectric conversion efficiency WPE is increased to greater than 70%). Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a light-emitting diode according to an embodiment of the present invention;

[0037] Figure 2 This is a secondary ion mass spectrum of a light-emitting diode according to an embodiment of the present invention;

[0038] Figure 3 This is a flowchart of a method for manufacturing a light-emitting diode according to an embodiment of the present invention.

[0039] Among them, the appendix Figures 1-3 The annotations in the attached figures are explained as follows:

[0040] 11-Substrate; 12-n-type semiconductor layer; 13-Quantum well layer; 14-Hole injection layer; 15-p-type semiconductor layer. Detailed Implementation

[0041] To make the objectives, advantages, and features of the present invention clearer, the light-emitting diode and its manufacturing method proposed in this invention will be further described in detail below. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0042] An embodiment of the present invention provides a light-emitting diode, comprising, from bottom to top, a substrate, an n-type semiconductor layer, a quantum well layer, a hole injection layer, and a p-type semiconductor layer. The hole injection layer contains p-type doped elements and n-type unintentionally doped elements, and the ratio a of the concentration of the p-type doped element to the concentration of the n-type unintentionally doped element is ≥80.

[0043] See below. Figure 1 and Figure 2 A more detailed description of the light-emitting diode provided in this embodiment is provided below. Figure 1 This is also a longitudinal cross-sectional view of a light-emitting diode.

[0044] The light-emitting diode includes, from bottom to top, a substrate 11, an n-type semiconductor layer 12, a quantum well layer 13, a hole injection layer 14, and a p-type semiconductor layer 15. The hole injection layer 14 contains p-type doped elements and n-type unintentionally doped elements. The concentration of the p-type doped elements is greater than the concentration of the n-type unintentionally doped elements, and the ratio a of the concentration of the p-type doped elements to the concentration of the n-type unintentionally doped elements is ≥80.

[0045] Because the hole injection layer 14 is inserted between the quantum well layer 13 and the p-type semiconductor layer 15, and the hole injection layer 14 contains p-type doped elements, the hole injection layer 14 can provide holes to the quantum well layer 13, thereby reducing the difference in electron and hole concentrations in the quantum well layer 13, increasing the probability of electron and hole wavefunction overlap, and increasing the recombination efficiency of electrons and holes in the quantum well layer 13, thus improving the luminous efficiency of the quantum well layer 13 and thereby improving the photoelectric conversion efficiency of the light-emitting diode. Furthermore, because a large number of electrons in the quantum well layer 13 can radiatively recombine with the holes provided by the hole injection layer 14, the probability of electrons in the quantum well layer 13 overflowing into the p-type semiconductor layer 15 and generating non-radiative recombination is reduced. This is equivalent to the hole injection layer 14 acting as an electron blocker, thus eliminating the need to insert an electron blocking layer between the quantum well layer 13 and the p-type semiconductor layer 15.

[0046] Specifically, because an n-type dopant is used when forming the n-type semiconductor layer 12 and the quantum well layer 13, the n-type semiconductor layer 12 and the quantum well layer 13 contain n-type doped elements; and because a p-type dopant is used when forming the hole injection layer 14 and the p-type semiconductor layer 15, the hole injection layer 14 and the p-type semiconductor layer 15 contain p-type doped elements. Furthermore, it should be noted that during the formation of the hole injection layer 14, an n-type dopant is not used to n-type dope the hole injection layer 14; the hole injection layer 14 itself contains background n-type unintentional doped elements, or the n-type doped elements in the quantum well layer 13 diffuse into the hole injection layer 14, making the hole injection layer 14 contain n-type unintentional doped elements.

[0047] Because the hole injection layer 14 contains p-type doped elements and n-type unintentionally doped elements instead of n-type doped elements, the concentration of p-type doped elements in the hole injection layer 14 is greater than the concentration of n-type unintentionally doped elements. The ratio of the concentration of p-type doped elements to the concentration of n-type unintentionally doped elements, a, is ≥ 80. This improves the solubility and ionization rate of p-type doped elements, thereby increasing the hole concentration in the hole injection layer 14 and further improving the photoelectric conversion efficiency of the light-emitting diode.

[0048] Preferably, the p-type dopant is magnesium, the n-type unintentional dopant is silicon, the concentration of the p-type dopant magnesium in the hole injection layer 14 is greater than the concentration of the n-type unintentional dopant silicon, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the n-type unintentional dopant silicon is greater than or equal to 80, which can improve the solubility and ionization efficiency of the p-type dopant magnesium, thereby increasing the hole concentration in the hole injection layer 14.

[0049] It should be noted that, in other embodiments, the p-type dopant element may also be zinc, calcium, beryllium, manganese, etc., and the n-type unintentional dopant element may also be germanium, tin, titanium, zirconium, etc.

[0050] The hole injection layer 14 is made of Al. x In y Ga 1-x-y N, 0≤x≤1, 0≤y≤1, wherein the hole injection layer 14 is made of at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN and AlInN.

[0051] The n-type semiconductor layer 12, the quantum well layer 13, and the p-type semiconductor layer 15 can be made of at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN, and AlInN.

[0052] Since the MO source used to form the hole injection layer 14 may contain at least one of trimethylgallium (TMGa), trimethylindium (TMIn), trimethylaluminum (TMAl), and triethylgallium (TEGa), and the MO source may also contain oxygen, at least one of carbon, hydrogen, and oxygen will remain in the formed hole injection layer 14.

[0053] When the hole injection layer 14 contains carbon, if the ratio b of the concentration of the p-type dopant magnesium to the concentration of carbon is less than 10, the excessively high concentration of carbon will act as a defect impurity, reducing the solubility of the p-type dopant magnesium and thus reducing its ionization efficiency. Consequently, the hole concentration in the hole injection layer 14 will decrease to less than 1E17 cm⁻¹. -3 When the ratio b of the concentration of the p-type doped element magnesium to the concentration of the carbon element is greater than 800, the high concentration of the p-type doped element magnesium will lead to the formation of light absorption by magnesium-related impurities, thereby causing a decrease in the photoelectric conversion efficiency (WPE).

[0054] When the hole injection layer 14 contains oxygen, if the ratio c of the concentration of the p-type dopant magnesium to the concentration of the oxygen is less than 15, the high concentration of oxygen reacts with the p-type dopant magnesium to form more complexes, which reduces the solubility of the p-type dopant magnesium and thus reduces its ionization efficiency. Consequently, the hole concentration in the hole injection layer 14 decreases to less than 1E17 cm⁻¹. -3When the ratio c of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is greater than 800, the high concentration of the p-type doped element magnesium will lead to the formation of light absorption by magnesium-related impurities, thereby causing a decrease in photoelectric conversion efficiency.

[0055] When the hole injection layer 14 contains hydrogen, if the ratio d of the concentration of the p-type dopant magnesium to the concentration of hydrogen is less than 1, the high concentration of hydrogen will react with the p-type dopant magnesium to form more complexes, thus reducing the ionization efficiency of the p-type dopant magnesium. Consequently, the hole concentration in the hole injection layer 14 will decrease to less than 1E17 cm⁻¹. -3 When the ratio d of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is greater than 50, the high concentration of the p-type doped element magnesium will lead to the formation of light absorption by magnesium-related impurities, thereby causing a decrease in photoelectric conversion efficiency.

[0056] Therefore, preferably, when the hole injection layer 14 contains carbon, the ratio of the concentration of the p-type dopant magnesium to the concentration of the carbon is 10 ≤ b ≤ 800; when the hole injection layer 14 contains oxygen, the ratio of the concentration of the p-type dopant magnesium to the concentration of the oxygen is 15 ≤ c ≤ 800; and when the hole injection layer 14 contains hydrogen, the ratio of the concentration of the p-type dopant magnesium to the concentration of the hydrogen is 1 ≤ d ≤ 50. This increases the solubility and ionization rate of the p-type dopant magnesium in the hole injection layer 14, thereby increasing the hole concentration to 5E17 cm⁻¹. -3 The above measures improve the photoelectric conversion efficiency.

[0057] Furthermore, when the thickness of the hole injection layer 14 is less than 10 nm, the total number of holes in the hole injection layer 14 is insufficient, resulting in insufficient holes injected from the hole injection layer 14 into the quantum well layer 13, thereby causing the photoelectric conversion efficiency to drop below 50%. When the thickness of the hole injection layer 14 is greater than 50 nm, the magnesium-related impurities of the p-type dopant element in the hole injection layer 14 will undergo nonradiative recombination with light absorption, thereby causing the photoelectric conversion efficiency to drop below 60%. Therefore, preferably, the thickness of the hole injection layer 14 is 10 nm to 50 nm to improve the photoelectric conversion efficiency.

[0058] Furthermore, secondary ion mass spectrometry (SIMS) can be used to test the concentration or signal intensity of each element in each semiconductor layer of the light-emitting diode. For example... Figure 2As shown, the horizontal axis represents depth, the left vertical axis represents concentration, and the right vertical axis represents signal intensity. Figure 2 The diagram shows the signal intensity variation trends of aluminum, gallium, and indium elements in the p-type semiconductor layer 15, the hole injection layer 14, and the quantum well layer 13, and also shows the concentration variation trends of hydrogen, carbon, oxygen, magnesium, silicon, and nitrogen elements in the p-type semiconductor layer 15, the hole injection layer 14, and the quantum well layer 13. Figure 2 As can be seen, in the hole injection layer 14, the concentration of the p-type doped element magnesium is greater than the concentration of the n-type unintentionally doped element silicon, the concentration of the p-type doped element magnesium is greater than the concentration of the carbon element, the concentration of the p-type doped element magnesium is greater than the concentration of the oxygen element, the concentration of the p-type doped element magnesium is greater than or equal to the concentration of the hydrogen element, and the signal intensity of Al is greater than the signal intensity of In.

[0059] When 0 < x < 1 and 0 < y < 1, the hole injection layer 14 contains Al and In. Preferably, the ratio of the signal intensities of Al to In in the hole injection layer 14 measured by the secondary ion mass spectrometer is 300 to 1E5. This is to avoid the situation where the signal intensity ratio of Al to In in the hole injection layer 14 is less than 300, resulting in too high a proportion of In and causing light absorption, which in turn leads to a decrease in photoelectric conversion efficiency. It also avoids the situation where the signal intensity ratio of Al to In in the hole injection layer 14 is greater than 1E5, resulting in too high a proportion of Al and too low magnesium ionization efficiency, which in turn leads to a hole concentration in the hole injection layer 14 being less than 1E17 cm⁻¹. -3 .

[0060] As can be seen from the above, the light-emitting diode of the present invention includes, from bottom to top, a substrate, an n-type semiconductor layer, a quantum well layer, a hole injection layer, and a p-type semiconductor layer. The hole injection layer contains p-type dopant elements and n-type unintentional dopant elements, and the ratio of the concentration of the p-type dopant element to the concentration of the n-type unintentional dopant element, a, is ≥ 80, thereby increasing the hole concentration in the hole injection layer (for example, the hole concentration can be increased to 5E17 cm⁻¹). -3 (as described above), thereby significantly reducing the difference in electron and hole concentrations in the quantum well layer, which in turn significantly improves the photoelectric conversion efficiency of the light-emitting diode (e.g., the photoelectric conversion efficiency can be increased to greater than 70%).

[0061] One embodiment of the present invention provides a method for manufacturing a light-emitting diode, see below. Figure 3 , Figure 3 This is a flowchart of a method for manufacturing a light-emitting diode according to an embodiment of the present invention. The method for manufacturing a light-emitting diode includes:

[0062] Step S1, provide a substrate;

[0063] Step S2: An n-type semiconductor layer, a quantum well layer, a hole injection layer, and a p-type semiconductor layer are sequentially formed on the substrate. The hole injection layer contains p-type doped elements and n-type unintentional doped elements, and the ratio a of the concentration of the p-type doped element to the concentration of the n-type unintentional doped element is ≥80.

[0064] See below. Figure 1 and Figure 2 The manufacturing method of the light-emitting diode provided in this embodiment will be described in more detail.

[0065] According to step S1, a substrate 11 is provided.

[0066] According to step S2, an n-type semiconductor layer 12, a quantum well layer 13, a hole injection layer 14, and a p-type semiconductor layer 15 are sequentially formed on the substrate 11. The hole injection layer 14 contains p-type doped elements and n-type unintentional doped elements. The concentration of the p-type doped elements is greater than the concentration of the n-type unintentional doped elements, and the ratio a of the concentration of the p-type doped elements to the concentration of the n-type unintentional doped elements is ≥ 80.

[0067] Because the hole injection layer 14 is inserted between the quantum well layer 13 and the p-type semiconductor layer 15, and the hole injection layer 14 contains p-type doped elements, the hole injection layer 14 can provide holes to the quantum well layer 13, thereby reducing the difference in electron and hole concentrations in the quantum well layer 13, increasing the probability of electron and hole wavefunction overlap, and increasing the recombination efficiency of electrons and holes in the quantum well layer 13, thus improving the luminous efficiency of the quantum well layer 13 and thereby improving the photoelectric conversion efficiency of the light-emitting diode. Furthermore, because a large number of electrons in the quantum well layer 13 can radiatively recombine with the holes provided by the hole injection layer 14, the probability of electrons in the quantum well layer 13 overflowing into the p-type semiconductor layer 15 and generating non-radiative recombination is reduced. This is equivalent to the hole injection layer 14 acting as an electron blocker, thus eliminating the need to insert an electron blocking layer between the quantum well layer 13 and the p-type semiconductor layer 15.

[0068] The n-type semiconductor layer 12, the quantum well layer 13, the hole injection layer 14, and the p-type semiconductor layer 15 are sequentially formed on the substrate 11 using an MO source and dopant via epitaxial growth. When forming the n-type semiconductor layer 12 and the quantum well layer 13, an n-type dopant is used, ensuring that the n-type semiconductor layer 12 and the quantum well layer 13 contain n-type doped elements. When forming the hole injection layer 14 and the p-type semiconductor layer 15, a p-type dopant is used, ensuring that the hole injection layer 14 and the p-type semiconductor layer 15 contain p-type doped elements. It should be noted that during the growth of the hole injection layer 14, an n-type dopant is not used to n-type dope the hole injection layer 14. The hole injection layer 14 itself contains unintentionally added background n-type dopant elements, or the n-type dopant elements in the quantum well layer 13 diffuse into the hole injection layer 14, resulting in the hole injection layer 14 containing unintentionally added n-type dopant elements.

[0069] Because the hole injection layer 14 contains p-type doped elements and n-type unintentionally doped elements instead of n-type doped elements, the concentration of p-type doped elements in the hole injection layer 14 is greater than the concentration of n-type unintentionally doped elements. The ratio of the concentration of p-type doped elements to the concentration of n-type unintentionally doped elements, a, is ≥ 80. This improves the solubility and ionization rate of p-type doped elements, thereby increasing the hole concentration in the hole injection layer 14 and further improving the photoelectric conversion efficiency of the light-emitting diode.

[0070] Preferably, the p-type dopant is magnesium, and the n-type unintentional dopant is silicon. Therefore, during the growth of the hole injection layer 14, instead of magnesium-silicon co-doping, only magnesium is doped into the hole injection layer 14. The silicon in the hole injection layer 14 is unintentionally doped, resulting in a higher concentration of p-type magnesium than n-type silicon. The ratio of the p-type magnesium concentration to the n-type silicon concentration is greater than or equal to 80, thereby improving the solubility and ionization efficiency of the p-type magnesium, and thus increasing the hole concentration in the hole injection layer 14.

[0071] It should be noted that, in other embodiments, the p-type dopant element may also be zinc, calcium, beryllium, manganese, etc., and the n-type unintentional dopant element may also be germanium, tin, titanium, zirconium, etc.

[0072] The hole injection layer 14 is made of Al. x In y Ga 1-x-yN, 0≤x≤1, 0≤y≤1, wherein the hole injection layer 14 is made of at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN and AlInN.

[0073] The n-type semiconductor layer 12, the quantum well layer 13, and the p-type semiconductor layer 15 can be made of at least one of GaN, AlGaN, InGaN, AlInGaN, AlN, InN, and AlInN.

[0074] The MO source used to grow the hole injection layer 14 may include at least one of trimethylgallium (TMGa), trimethylindium (TMIn), trimethylaluminum (TMAl), and triethylgallium (TEGa), and the MO source may also contain oxygen. Therefore, at least one of carbon, hydrogen, and oxygen will remain as impurities in the formed hole injection layer 14.

[0075] When the hole injection layer 14 contains carbon, if the ratio b of the concentration of the p-type dopant magnesium to the concentration of carbon is less than 10, the excessively high concentration of carbon will act as a defect impurity, reducing the solubility of the p-type dopant magnesium and thus reducing its ionization efficiency. Consequently, the hole concentration in the hole injection layer 14 will decrease to less than 1E17 cm⁻¹. -3 When the ratio b of the concentration of the p-type doped element magnesium to the concentration of the carbon element is greater than 800, the high concentration of the p-type doped element magnesium will lead to the formation of light absorption by magnesium-related impurities, thereby causing a decrease in the photoelectric conversion efficiency (WPE).

[0076] When the hole injection layer 14 contains oxygen, if the ratio c of the concentration of the p-type dopant magnesium to the concentration of the oxygen is less than 15, the high concentration of oxygen reacts with the p-type dopant magnesium to form more complexes, which reduces the solubility of the p-type dopant magnesium and thus reduces its ionization efficiency. Consequently, the hole concentration in the hole injection layer 14 decreases to less than 1E17 cm⁻¹. -3 When the ratio c of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is greater than 800, the high concentration of the p-type doped element magnesium will lead to the formation of light absorption by magnesium-related impurities, thereby causing a decrease in photoelectric conversion efficiency.

[0077] When the hole injection layer 14 contains hydrogen, if the ratio d of the concentration of the p-type dopant magnesium to the concentration of hydrogen is less than 1, the high concentration of hydrogen will react with the p-type dopant magnesium to form more complexes, thus reducing the ionization efficiency of the p-type dopant magnesium. Consequently, the hole concentration in the hole injection layer 14 will decrease to less than 1E17 cm⁻¹. -3 When the ratio d of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is greater than 50, the high concentration of the p-type doped element magnesium will lead to the formation of light absorption by magnesium-related impurities, thereby causing a decrease in photoelectric conversion efficiency.

[0078] Therefore, preferably, when the hole injection layer 14 contains carbon, the ratio of the concentration of the p-type dopant magnesium to the concentration of the carbon is 10 ≤ b ≤ 800; when the hole injection layer 14 contains oxygen, the ratio of the concentration of the p-type dopant magnesium to the concentration of the oxygen is 15 ≤ c ≤ 800; and when the hole injection layer 14 contains hydrogen, the ratio of the concentration of the p-type dopant magnesium to the concentration of the hydrogen is 1 ≤ d ≤ 50. This increases the solubility and ionization rate of the p-type dopant magnesium in the hole injection layer 14, thereby increasing the hole concentration to 5E17 cm⁻¹. -3 The above measures improve the photoelectric conversion efficiency.

[0079] Furthermore, when the thickness of the hole injection layer 14 is less than 10 nm, the total number of holes in the hole injection layer 14 is insufficient, resulting in insufficient holes injected from the hole injection layer 14 into the quantum well layer 13, thereby causing the photoelectric conversion efficiency to drop below 50%. When the thickness of the hole injection layer 14 is greater than 50 nm, the magnesium-related impurities of the p-type dopant element in the hole injection layer 14 will undergo nonradiative recombination with light absorption, thereby causing the photoelectric conversion efficiency to drop below 60%. Therefore, preferably, the thickness of the hole injection layer 14 is 10 nm to 50 nm to improve the photoelectric conversion efficiency.

[0080] Furthermore, secondary ion mass spectrometry (SIMS) can be used to test the concentration or signal intensity of each element in each semiconductor layer of the light-emitting diode. For example... Figure 2 As shown, the horizontal axis represents depth, the left vertical axis represents concentration, and the right vertical axis represents signal intensity. Figure 2The diagram shows the signal intensity variation trends of aluminum, gallium, and indium elements in the p-type semiconductor layer 15, the hole injection layer 14, and the quantum well layer 13, and also shows the concentration variation trends of hydrogen, carbon, oxygen, magnesium, silicon, and nitrogen elements in the p-type semiconductor layer 15, the hole injection layer 14, and the quantum well layer 13. Figure 2 As can be seen, in the hole injection layer 14, the concentration of the p-type doped element magnesium is greater than the concentration of the n-type unintentionally doped element silicon, the concentration of the p-type doped element magnesium is greater than the concentration of the carbon element, the concentration of the p-type doped element magnesium is greater than the concentration of the oxygen element, the concentration of the p-type doped element magnesium is greater than or equal to the concentration of the hydrogen element, and the signal intensity of Al is greater than the signal intensity of In.

[0081] When 0 < x < 1 and 0 < y < 1, the hole injection layer 14 contains Al and In. Preferably, the ratio of the signal intensities of Al to In in the hole injection layer 14 measured by the secondary ion mass spectrometer is 300 to 1E5. This is to avoid the situation where the signal intensity ratio of Al to In in the hole injection layer 14 is less than 300, resulting in too high a proportion of In and causing light absorption, which in turn leads to a decrease in photoelectric conversion efficiency. It also avoids the situation where the signal intensity ratio of Al to In in the hole injection layer 14 is greater than 1E5, resulting in too high a proportion of Al and too low magnesium ionization efficiency, which in turn leads to a hole concentration in the hole injection layer 14 being less than 1E17 cm⁻¹. -3 .

[0082] As can be seen from the above, the method for manufacturing the light-emitting diode of the present invention includes providing a substrate; sequentially forming an n-type semiconductor layer, a quantum well layer, a hole injection layer, and a p-type semiconductor layer on the substrate, wherein the hole injection layer comprises a p-type dopant and an n-type unintentional dopant, and the ratio of the concentration of the p-type dopant to the concentration of the n-type unintentional dopant, a, is ≥ 80, thereby increasing the hole concentration in the hole injection layer (for example, the hole concentration can be increased to 5E17 cm⁻¹). -3 (as described above), thereby significantly reducing the difference in electron and hole concentrations in the quantum well layer, which in turn significantly improves the photoelectric conversion efficiency of the light-emitting diode (e.g., the photoelectric conversion efficiency can be increased to greater than 70%).

[0083] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A light-emitting diode, characterized in that, It includes, from bottom to top, a substrate, an n-type semiconductor layer, a quantum well layer, a hole injection layer, and a p-type semiconductor layer. The hole injection layer contains p-type doped elements and n-type unintentional doped elements, and the ratio of the concentration of the p-type doped element to the concentration of the n-type unintentional doped element, a, is ≥ 80.

2. The light-emitting diode as described in claim 1, characterized in that, The p-type dopant is magnesium, and the n-type unintentional dopant is silicon.

3. The light-emitting diode as described in claim 2, characterized in that, The hole injection layer also contains carbon, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the carbon is b, where 10 ≤ b ≤ 800.

4. The light-emitting diode as described in claim 2, characterized in that, The hole injection layer also contains oxygen, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the oxygen is c, where 15 ≤ c ≤ 800.

5. The light-emitting diode as described in claim 2, characterized in that, The hole injection layer also contains hydrogen, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the hydrogen is d, where 1 ≤ d ≤ 50.

6. The light-emitting diode as described in claim 2, characterized in that, The hole injection layer also contains carbon and oxygen elements. The ratio of the concentration of the p-type doped element magnesium to the concentration of the carbon element is b, where 10 ≤ b ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is c, where 15 ≤ c ≤ 800.

7. The light-emitting diode as described in claim 2, characterized in that, The hole injection layer also contains carbon and hydrogen elements. The ratio of the concentration of the p-type doped element magnesium to the concentration of the carbon element is b, where 10 ≤ b ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, where 1 ≤ d ≤ 50.

8. The light-emitting diode as described in claim 2, characterized in that, The hole injection layer also contains oxygen and hydrogen elements. The ratio of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is c, where 15 ≤ c ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, where 1 ≤ d ≤ 50.

9. The light-emitting diode as described in claim 2, characterized in that, The hole injection layer also contains carbon, oxygen, and hydrogen elements. The ratio of the concentration of the p-type doped magnesium element to the concentration of the carbon element is b, where 10 ≤ b ≤ 800; the ratio of the concentration of the p-type doped magnesium element to the concentration of the oxygen element is c, where 15 ≤ c ≤ 800; and the ratio of the concentration of the p-type doped magnesium element to the concentration of the hydrogen element is d, where 1 ≤ d ≤ 50.

10. The light-emitting diode as claimed in claim 1, characterized in that, The thickness of the hole injection layer is 10nm to 50nm.

11. The light-emitting diode as claimed in claim 1, characterized in that, The hole injection layer is made of Al. x In y Ga 1-x-y N, 0≤x≤1, 0≤y≤1.

12. The light-emitting diode as claimed in claim 11, characterized in that, When 0 < x < 1 and 0 < y < 1, the ratio of Al to In signal intensities in the hole injection layer measured by the secondary ion mass spectrometer is 300 to 1E5.

13. The light-emitting diode as claimed in claim 1, characterized in that, The hole concentration in the hole injection layer is greater than or equal to 5E17cm⁻¹ -3 .

14. A method for manufacturing a light-emitting diode, characterized in that, include: Provide a substrate; An n-type semiconductor layer, a quantum well layer, a hole injection layer, and a p-type semiconductor layer are sequentially formed on the substrate. The hole injection layer contains p-type doped elements and n-type unintentional doped elements, and the ratio of the concentration of the p-type doped element to the concentration of the n-type unintentional doped element, a, is ≥ 80.

15. The method for manufacturing a light-emitting diode as described in claim 14, characterized in that, The p-type dopant is magnesium, and the n-type unintentional dopant is silicon.

16. The method for manufacturing a light-emitting diode as described in claim 15, characterized in that, The hole injection layer also contains carbon, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the carbon is b, where 10 ≤ b ≤ 800.

17. The method for manufacturing a light-emitting diode as described in claim 15, characterized in that, The hole injection layer also contains oxygen, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the oxygen is c, where 15 ≤ c ≤ 800.

18. The method for manufacturing a light-emitting diode as described in claim 15, characterized in that, The hole injection layer also contains hydrogen, and the ratio of the concentration of the p-type dopant magnesium to the concentration of the hydrogen is d, where 1 ≤ d ≤ 50.

19. The method for manufacturing a light-emitting diode as described in claim 15, characterized in that, The hole injection layer also contains carbon and oxygen elements. The ratio of the concentration of the p-type doped element magnesium to the concentration of the carbon element is b, where 10 ≤ b ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is c, where 15 ≤ c ≤ 800.

20. The method for manufacturing a light-emitting diode as described in claim 15, characterized in that, The hole injection layer also contains carbon and hydrogen elements. The ratio of the concentration of the p-type doped element magnesium to the concentration of the carbon element is b, where 10 ≤ b ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, where 1 ≤ d ≤ 50.

21. The method for manufacturing a light-emitting diode as described in claim 15, characterized in that, The hole injection layer also contains oxygen and hydrogen elements. The ratio of the concentration of the p-type doped element magnesium to the concentration of the oxygen element is c, where 15 ≤ c ≤ 800; the ratio of the concentration of the p-type doped element magnesium to the concentration of the hydrogen element is d, where 1 ≤ d ≤ 50.

22. The method for manufacturing a light-emitting diode as described in claim 15, characterized in that, The hole injection layer also contains carbon, oxygen, and hydrogen elements. The ratio of the concentration of the p-type doped magnesium element to the concentration of the carbon element is b, where 10 ≤ b ≤ 800; the ratio of the concentration of the p-type doped magnesium element to the concentration of the oxygen element is c, where 15 ≤ c ≤ 800; and the ratio of the concentration of the p-type doped magnesium element to the concentration of the hydrogen element is d, where 1 ≤ d ≤ 50.

23. The method for manufacturing a light-emitting diode as described in claim 14, characterized in that, The thickness of the hole injection layer is 10nm to 50nm.

24. The method for manufacturing a light-emitting diode as described in claim 14, characterized in that, The hole injection layer is made of Al. x In y Ga 1-x-y N, 0≤x≤1, 0≤y≤1.

25. The method for manufacturing a light-emitting diode as described in claim 24, characterized in that, When 0 < x < 1 and 0 < y < 1, the ratio of Al to In signal intensities in the hole injection layer measured by the secondary ion mass spectrometer is 300 to 1E5.

26. The method for manufacturing a light-emitting diode as described in claim 14, characterized in that, The hole concentration in the hole injection layer is greater than or equal to 5E17cm⁻¹ -3 .

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