Light-emitting diode, light-emitting device and light-emitting device
By forming a P-type doped ohmic contact layer on one side of the N-type semiconductor layer of the Micro LED chip and using a transparent conductive material as the electrode, the problem of light absorption by the metal electrode is solved, resulting in better light output and electrical performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-04
- Publication Date
- 2026-03-27
AI Technical Summary
The metal electrodes of existing Micro LED chips have high photon absorption and low light transmittance, resulting in a reduced light-emitting area and low light extraction efficiency, which increases the difficulty of the process.
A first ohmic contact layer doped with P-type is formed on one side of the N-type semiconductor layer, and a transparent conductive material is used as the electrode to avoid the formation of a metal layer. A positive tunneling current is generated by the built-in electric field to ensure good electrical performance while reducing light absorption.
It improves the light emission effect and electrical performance of light-emitting diodes, reduces contact resistance and operating voltage, and enhances the light emission area.
Smart Images
Figure CN121751832A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a light-emitting diode, a light-emitting device, and a light-emitting apparatus. Background Technology
[0002] The basic structure of a light-emitting diode (LED) consists of a PN junction between a P-type semiconductor and an N-type semiconductor. When a forward voltage is applied to the LED, electrons and holes recombine at the junction of the PN junction, releasing energy. This energy is emitted in the form of photons, forming light radiation.
[0003] With the continuous advancement of technology, augmented reality (AR) technology has made significant progress. On the one hand, AR technology can organically combine the real world with virtual reality; on the other hand, artificial intelligence technology has further promoted and improved the intelligence level of AR products, greatly enriching the perceptual experience of the virtual world while in the real environment. Micro LEDs, as the basic light-emitting unit, have a series of advantages such as high pixel density, high brightness, high contrast, lightweight, low power consumption, and good splicing ability, and are widely regarded as the mainstream display technology most suitable for AR.
[0004] Currently, mainstream AR Micro LED red light chips employ an epitaxial structure of AlGaInP quaternary material grown on a GaAs substrate. To achieve the highest possible nit value at the micrometer scale (<5 μm), a metal electrode is typically formed above the N-type semiconductor layer to ensure good ohmic contact with the N-type semiconductor layer. The P-electrode is usually a transparent conductive oxide (TCO) thin film electrode. However, due to the high absorption and low transmittance of the metal electrode, the effective light-emitting area is significantly reduced. Only a portion of the photons are emitted from the sidewall and diverge at an angle, requiring microlenses to converge the emitted beam. This not only results in low light extraction efficiency but also greatly increases the manufacturing complexity.
[0005] Therefore, in the chip design and manufacturing process, there is a need to provide an improved technical solution that addresses the various shortcomings of the existing technology, so as to ensure the good electrical performance of the LED chip and improve the light output effect of the LED chip. Summary of the Invention
[0006] In view of the defects and shortcomings of the existing light-emitting diodes in terms of light emission, the purpose of this application is to provide a light-emitting diode, a light-emitting device, and a light-emitting apparatus to obtain a light-emitting diode product with better light emission effect and more reliable quality.
[0007] To achieve the above and other related objectives, in a first aspect, this application provides a light-emitting diode, which includes at least a semiconductor epitaxial stack, the semiconductor epitaxial stack including an N-type semiconductor layer, an active layer, a P-type semiconductor layer stacked sequentially, and a first ohmic contact layer and a second ohmic contact layer, the first ohmic contact layer being formed on the side of the N-type semiconductor layer away from the active layer, the second ohmic contact layer being formed on the side of the P-type semiconductor layer away from the active layer, and both the first ohmic contact layer and the second ohmic contact layer being P-type doped material layers.
[0008] This application also provides a light-emitting device, which includes:
[0009] A substrate, wherein a MOS device layer and an interconnect layer are formed on the MOS device layer;
[0010] A light-emitting unit is located above the substrate and electrically connected to the interconnect layer, and the light-emitting unit includes the light-emitting diode provided in this application.
[0011] This application also provides a light-emitting device, the light-emitting device comprising:
[0012] Drive substrate;
[0013] A plurality of light-emitting devices are arranged in an array above the driving substrate, and the driving substrate and the light-emitting devices are electrically connected; the light-emitting devices are the light-emitting devices provided in this application.
[0014] Compared with the prior art, the light-emitting diode, light-emitting device, and light-emitting apparatus provided in this application have at least the following beneficial effects:
[0015] In the technical solution of this application, a P-type doped first ohmic contact layer is formed on one side of the N-type semiconductor layer, and a first electrode made of transparent conductive material is formed above the first ohmic contact layer. This first electrode can form a forward current conduction from the first ohmic contact layer to the first electrode with the P-type first ohmic contact layer. Furthermore, a strong built-in electric field is formed between the heavily doped P-type first ohmic contact layer and the N-type semiconductor layer, making the valence band top electron energy level on the P side higher than the conduction band bottom electron energy level on the N side. Therefore, under the action of an applied electric field, a forward tunneling current can be generated from the N-type semiconductor layer to the P-type first ohmic contact layer, thus giving the light-emitting diode excellent electrical performance. Additionally, no metal material layer is formed between the first electrode and the first ohmic contact layer, thus reducing light absorption and blocking, which helps to increase the light emission area and improve the light emission effect of the light-emitting diode.
[0016] In addition, the light-emitting device and light-emitting apparatus provided in this application both include the light-emitting diodes provided in the above-mentioned technical solutions. Therefore, the light-emitting apparatus also has the above-mentioned good technical effects. Attached Figure Description
[0017] Figure 1 The diagram shows a schematic of a flip-chip light-emitting diode in the prior art.
[0018] Figure 2 The diagram shown is a schematic diagram of the structure of a light-emitting diode provided in Embodiment 1 of this application.
[0019] Figure 3 Shown as an optional embodiment Figure 2 The diagram shows a schematic of the structure of a semiconductor epitaxial stack.
[0020] Figure 4 Shown as another optional embodiment Figure 2 The diagram shows a schematic of the structure of a semiconductor epitaxial stack.
[0021] Figure 5 Shown as another optional embodiment Figure 2 The diagram shows a schematic of the structure of a semiconductor epitaxial stack.
[0022] Figure 6 Shown as another optional embodiment Figure 2 The diagram shows a schematic of the structure of a semiconductor epitaxial stack.
[0023] Figure 7 The diagram shown is a schematic diagram of the structure of the light-emitting device provided in Embodiment 2 of this application.
[0024] Figure 8 The diagram shown is a schematic diagram of the light-emitting device provided in Embodiment 3 of this application.
[0025] List of reference numerals in the attached diagram:
[0026] 11. N-type layer; 12. Light-emitting layer; 13. P-type layer; 14. Metal electrode.
[0027] 100. Light-emitting diode; 110. Semiconductor epitaxial stack; 111. N-type semiconductor layer; 1111. N-type space layer; 1112. N-type confinement layer; 1113. Heavily doped layer; 1114. N-type window layer; 112. Active layer; 113. P-type semiconductor layer; 1131. P-type space layer; 1132. P-type confinement layer; 1133. P-type transition layer; 1134. P-type window layer; 114. First ohmic contact layer; 115. Second ohmic contact layer; 121. First electrode; 122. Second electrode; 130. Metal layer; 141. First insulating layer; 142. Second insulating layer.
[0028] 200, Light-emitting device; 210, Substrate; 211, MOS device layer; 212, Interconnect layer.
[0029] 300. Display device; 301. Circuit board; 302. Light-emitting unit; 303. Circuit layer; 304. Housing. Detailed Implementation
[0030] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.
[0031] It should be noted that the illustrations provided in the embodiments of this application are merely schematic representations of the basic concept of this application. Although the illustrations only show components relevant to this application and are not drawn according to the actual number, shape, and size of components in implementation, the shape, quantity, and proportion of each component can be arbitrarily changed in actual implementation, and the layout of the components may also be more complex. The structures, proportions, sizes, etc., shown in the accompanying drawings are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.
[0032] See Figure 1 In the prior art, light-emitting diodes (LEDs) include an N-type layer 11, a light-emitting layer 12, and a P-type layer 13 stacked sequentially. To achieve a good ohmic contact, a metal electrode 14 is formed above the N-type layer. Although the metal electrode 14 can form a good ohmic contact with the N-type layer 11, since the LED emits light from the N-type layer 11 side, and the metal electrode 14 has strong light absorption, the placement of the metal electrode 14 severely affects the light emission performance, especially for Micro LEDs with a size of less than 5 μm.
[0033] In view of the background technology and the above-mentioned technical defects, this application provides a light-emitting diode, which includes at least a semiconductor epitaxial stack, wherein the semiconductor epitaxial stack includes an N-type semiconductor layer, an active layer, a P-type semiconductor layer stacked sequentially, and a first ohmic contact layer and a second ohmic contact layer. The first ohmic contact layer is formed on the side of the N-type semiconductor layer away from the active layer, and the second ohmic contact layer is formed on the side of the P-type semiconductor layer away from the active layer. Both the first ohmic contact layer and the second ohmic contact layer are P-type doped material layers.
[0034] By adopting the above technical solution, a P-type doped first ohmic contact is formed on one side of the N-type semiconductor layer, and instead of forming a metal layer on top to form an ohmic contact, a transparent conductive material is directly formed as the first electrode. The P-type doped first ohmic contact layer can form a forward current conduction from the P-type doped first ohmic contact layer to the first electrode. On the other hand, a strong built-in electric field is formed between the heavily doped P-type first ohmic contact layer and the N-type semiconductor layer, making the valence band top electron energy level on the P side higher than the conduction band bottom electron energy level on the N side. Therefore, under the action of an external electric field, a forward tunneling current can be generated from the N-type semiconductor layer to the P-type first ohmic contact layer, thus giving the light-emitting diode excellent electrical performance. In addition, since no metal layer is formed on the N-type semiconductor layer side, light absorption is reduced, which is beneficial to improving the light extraction effect of the light-emitting diode.
[0035] Optionally, the first ohmic contact layer is a P-type doped AlGaAs layer or an AlGaInP layer.
[0036] Optionally, the P-type doping concentration of the first ohmic contact layer is greater than or equal to 1.0E+19 atom / cm. 3 .
[0037] Optionally, the P-type doping concentration of the first ohmic contact layer is greater than or equal to 1.0E+20 atom / cm 3 .
[0038] Optionally, the thickness of the first ohmic contact is between 10 nm and 500 nm.
[0039] The setting of the P-type doping concentration and thickness of the first ohmic contact layer can ensure a good ohmic contact with the first electrode formed by the transparent conductive material, reduce the contact resistance and the operating voltage of the light-emitting diode, and ensure the good electrical performance of the light-emitting diode.
[0040] Optionally, the light-emitting diode further includes a first electrode and a second electrode. The first electrode is formed on the side of the N-type semiconductor layer away from the active layer and is in contact with the first ohmic contact layer. The second electrode is formed on the side of the P-type semiconductor layer away from the active layer and is in contact with the second ohmic contact layer. The first electrode and the second electrode are transparent electrodes.
[0041] Both the first and second electrodes are transparent electrodes, capable of forming good ohmic contacts with the p-type doped first and second ohmic contact layers, respectively. Forming the first electrode as a transparent electrode reduces light absorption and increases light emission, thus improving the light extraction performance of the LED.
[0042] Optionally, the N-type semiconductor layer includes at least an N-type confinement layer located between the active layer and the first ohmic contact layer.
[0043] Optionally, the thickness of the N-type confinement layer is 200 nm to 1000 nm.
[0044] The N-confinement layer ensures that the LED has a sufficient electron supply and can form good current conduction with the first ohmic contact layer; at the same time, it helps to limit the thermal escape of holes and improve the internal quantum efficiency of the LED.
[0045] Optionally, the N-type semiconductor layer further includes an N-type window layer located between the N-type confinement layer and the first ohmic contact layer.
[0046] Optionally, the thickness of the N-type window layer is 200 nm to 10000 nm.
[0047] The N-type window layer facilitates improved current spread on the N-type semiconductor layer side and also ensures good current conduction with the first ohmic contact layer. Furthermore, the thickness of the N-type window layer can be adjusted according to actual product requirements, satisfying diverse needs. Simultaneously, the thickness and doping concentration of the N-type window layer optimize the bandgap, enabling forward tunneling current from the N-type window layer to the first ohmic contact layer of the P-type semiconductor layer.
[0048] Optionally, the light-emitting diode further includes a heavily doped layer located between the N-type confinement layer and the first ohmic contact, wherein the heavily doped layer is an N-type doped material layer, and the doping concentration of the N-type confinement layer is lower than the doping concentration of the heavily doped layer.
[0049] Optionally, the light-emitting diode further includes a heavily doped layer located between the N-type window layer and the first ohmic contact, wherein the heavily doped layer is an N-type doped material layer, and the doping concentration of the N-type window layer is lower than the doping concentration of the heavily doped layer.
[0050] Optionally, the thickness of the heavily doped layer is between 10 nm and 500 nm.
[0051] Optionally, the N-type doping concentration of the heavily doped layer is greater than 5.0E+18 atom / cm. 3 .
[0052] Optionally, the heavily doped layer is an N-type doped AlGaAs layer or an AlGaInP layer.
[0053] The aforementioned heavily doped layer is an N-type doped layer, which can form a tunneling junction with the P-type doped first ohmic contact layer, further reducing the tunneling threshold condition and lowering the operating voltage. Furthermore, the doping concentration of the N-type window layer or N-type confinement layer is lower than that of the aforementioned heavily doped layer, thus reducing the absorption of photons by the impurity energy levels of the N-type window layer or N-type confinement layer, which is beneficial for improving light extraction efficiency.
[0054] Optionally, the P-type semiconductor layer includes at least a P-type window layer and a P-type confinement layer, the P-type confinement layer being located above the active layer, and the P-type window layer being located between the P-type confinement layer and the second ohmic contact layer.
[0055] The presence of a P-type semiconductor layer ensures that the light-emitting diode has a sufficient hole supply, enabling good electron-hole radiative recombination.
[0056] Optionally, the light-emitting diode further includes a metal layer, which is located on the side of the second electrode away from the semiconductor epitaxial stack and electrically connected to the second electrode.
[0057] The aforementioned metal layer can serve as part of the second electrode to conduct current; on the other hand, it can act as a bonding layer during the subsequent welding or die bonding process of the light-emitting diode, facilitating the fixation of the light-emitting diode and its electrical connection with other devices.
[0058] This application also provides a light-emitting device, which includes:
[0059] A substrate, wherein a device layer and an interconnect layer are formed on the device layer;
[0060] A light-emitting unit is located above the substrate and electrically connected to the interconnect layer, and the light-emitting unit includes the light-emitting diode provided in this application.
[0061] This light-emitting device includes the aforementioned light-emitting diode of this application, and therefore also has good light emission performance. The light-emitting diode is electrically connected to the device layer via the first electrode and the second electrode through the interconnect layer, and the switching control of the light-emitting diode is realized through the device.
[0062] This application also provides a light-emitting device, the light-emitting device comprising:
[0063] Drive substrate;
[0064] A plurality of light-emitting devices are arranged in an array above the driving substrate, and the driving substrate and the light-emitting devices are electrically connected; the light-emitting devices are the light-emitting devices provided in this application.
[0065] The light-emitting device includes the light-emitting device described above in this application, and therefore also has better light emission effect and good control performance.
[0066] The following examples will now be used to provide a detailed description. For ease of understanding, the growth direction of the semiconductor epitaxial stack is defined as growing from bottom to top, with the substrate located below the semiconductor epitaxial stack and the electrode structure located above the semiconductor epitaxial stack.
[0067] Example 1
[0068] This embodiment provides a light-emitting diode (LED), see [link]. Figure 2 The light-emitting diode 100 includes a semiconductor stack 110, which can be any material capable of emitting light under voltage, such as GaN, AlGaN, AlInP, AlGaInP, or AlGaP. Similarly, as... Figure 2 As shown, the semiconductor epitaxial stack 110 includes an N-type semiconductor layer 111, an active layer 112, and a P-type semiconductor layer 113, as well as a first ohmic contact layer 114 formed on the side of the N-type semiconductor layer 111 away from the active layer 112, and a second ohmic contact layer 115 formed on the side of the P-type semiconductor layer 113 away from the active layer 112.
[0069] The N-type semiconductor layer 111, active layer 112, and P-type semiconductor layer 113 may include semiconductor material layers of group III-V elements, such as Al, Ga, In, and P. The N-type semiconductor layer 111 may include N-type impurities such as Si, Ge, and Sn, while the P-type semiconductor layer 113 may include P-type impurities such as Mg, Sr, Ba, and Zn. The active layer 202 provides the region for electron-hole recombination and emits light. Different materials can be selected depending on the emission wavelength. The active layer 112 is made of aluminum gallium indium phosphide (AlGaInP) series materials, emitting red, yellow, or orange light. The active layer 112 can be a single heterostructure (SH), a double heterostructure (DH), a double-sided double heterostructure (DDH), or a multiquantum well (MQW). The active layer 112 comprises a well layer and a barrier layer, wherein the barrier layer has a larger band gap than the well layer. By adjusting the composition ratio of the semiconductor material in the active layer 112, it is desired to radiate light of different wavelengths. In this embodiment, the active layer 112 radiates light in the 550 nm to 750 nm wavelength range, such as red, yellow, and orange light, and further, radiates red light. The active layer 112 is a material layer that provides electroluminescent radiation, such as aluminum gallium indium phosphide (AGaInP) or aluminum gallium arsenide (AGaAs), more preferably AGaInP, which can be a single quantum well or a multi-quantum well.
[0070] In this embodiment, the active layer 112 may optionally be a multi-quantum-well layer, comprising alternating AlGaInP quantum well layers and AlGaInP quantum barrier layers, wherein the Al content in the AlGaInP quantum well layers and AlGaInP quantum barrier layers is different. The multi-quantum-well layer may comprise alternating stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers for 1 to 200 cycles. As an example, the multi-quantum-well layer 112 comprises alternating stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers for 5 cycles.
[0071] Similarly, refer to Figure 2 The first ohmic contact layer 114 is formed on the side of the N-type semiconductor layer 111 away from the active layer 112. In this embodiment, the first ohmic contact layer 114 is a heavily doped P-type material layer. Optionally, the first ohmic contact layer 114 is a P-type doped AlGaAs layer or an AlGaInP layer. The P-type impurity can also be Mg, Sr, Ba, Zn, C, etc. The P-type doping concentration of the first ohmic contact layer 114 is greater than or equal to 1.0E+19 atom / cm³. 3Furthermore, the p-type doping concentration of the first ohmic contact layer 114 is greater than or equal to 1.0E+20 atom / cm. 3 Optionally, the thickness of the first ohmic contact layer 114 is between 10 nm and 500 nm, and more specifically, between 50 nm and 500 nm, 100 nm and 500 nm, 50 nm and 400 nm, 100 nm and 200 nm. A higher doping concentration and a certain thickness facilitate the formation of a strong built-in electric field between the first ohmic contact layer 114 and the adjacent N-type semiconductor layer 111, making the valence band top electron energy level on the P-side higher than the conduction band bottom electron energy level on the N-side. This facilitates the generation of tunneling current from the N-type semiconductor layer 111 to the first ohmic contact layer 114 under the action of an applied electric field, ensuring good electrical performance of the light-emitting diode.
[0072] Similarly, refer to Figure 2 The light-emitting diode 100 in this embodiment also includes a first electrode 121 and a second electrode 122. The first electrode is formed on the side of the N-type semiconductor layer 111 away from the active layer 112 and is electrically connected to the N-type semiconductor layer 111. Specifically, the first electrode 121 is formed on the side of the first ohmic contact layer 114 away from the N-type semiconductor layer 111 and is electrically connected to the first ohmic contact layer 114. As shown in the figure, the first ohmic contact layer 114 is in direct contact with the first electrode 121, and no metal electrode is formed between them. Therefore, light absorption caused by the formation of a metal electrode is reduced, which helps to increase the light-emitting area of the light-emitting diode 100 and improve the light-emitting effect.
[0073] Reference Figure 3 In an optional example of this embodiment, in the direction of gradually moving away from the active layer 112 (i.e., Figure 3 In the semiconductor stack 110 (from bottom to top), the N-type semiconductor layer 111 may include an N-type space layer 1111 and an N-type confinement layer 1112 stacked sequentially. The N-type space layer 1111 may optionally be an unintentionally doped AlGaInP layer, and the N-type confinement layer 1112 may be an N-type doped AlInP layer, such as a Si-doped AlInP layer. Its function is to provide sufficient electrons for LED light emission and allow electrons to move smoothly to the active layer 322 for radiative recombination, effectively improving the overall luminous efficiency of the LED. Furthermore, the thickness of the N-type confinement layer 1112 is 200 nm to 1000 nm. This thickness of the N-type confinement layer 1112 helps to limit the thermal escape of holes and improve the internal quantum efficiency of the LED. The N-type space layer 1111 can prevent doped atoms from diffusing into the active region and causing non-radiative recombination.
[0074] In optional embodiments, the thickness of the N-type confinement layer 1112 is 200 nm to 1000 nm, and more specifically 300 nm to 1000 nm, 500 nm to 1000 nm, 300 nm to 800 nm, 500 nm to 800 nm, etc. The doping concentration of the N-type confinement layer 1112 is greater than 5.0E+17 atom / cm. 3 The first ohmic contact layer 114 is formed above the N-type confinement layer 1112. The thickness and doping concentration of the N-type confinement layer 1112 are conducive to the optimization of the energy band, realizing the forward tunneling current from the N-type AlInP confinement layer to the P-type first ohmic contact layer 114.
[0075] In another alternative embodiment, such as Figure 4 As shown, a heavily doped layer 1113 is formed between the N-type confinement layer 1112 and the first ohmic contact layer 114. This heavily doped layer 1113 is an N-type heavily doped layer. More specifically, the N-type dopant in the heavily doped layer 1113 is the same as the dopant in the N-type confinement layer 1112, for example, both being Si. Furthermore, the heavily doped layer 1113 can have the same material layer as the N-type confinement layer 1112, or it can be a different material layer. In an optional example, the N-type confinement layer is an AlInP layer, and the heavily doped layer 1113 is an AlGaAs layer or an AlGaInP layer. The thickness of the heavily doped layer 1113 is between 10 nm and 500 nm, and more specifically, 50 nm to 200 nm, 100 nm to 200 nm, 100 nm to 150 nm, 150 nm to 200 nm, etc. The N-type doping concentration of the heavily doped layer 1113 is greater than that of the N-type confinement layer 1112. Optionally, the doping concentration of the heavily doped layer 1113 is greater than 5.0E+18 atom / cm. 3 Furthermore, greater than 1.0E+19 atom / cm 3 .
[0076] The aforementioned heavily doped layer 1113 is an N-type doped layer, which can form a tunnel junction with the P-type doped first ohmic contact layer 114, further reducing the tunneling threshold condition and lowering the operating voltage of the light-emitting diode 100. Furthermore, the doping concentration of the N-type confinement layer 1112 is lower than that of the heavily doped layer 1113, thus reducing the absorption of photons by the impurity energy levels of the N-type confinement layer 1112, which is beneficial for improving light extraction efficiency.
[0077] In another optional embodiment of this example, such as Figure 5 As shown, in the direction gradually moving away from the active layer 112 (i.e., Figure 5In the semiconductor stack 110 (from bottom to top), the N-type semiconductor layer 111 may include an N-type space layer 1111, an N-type confinement layer 1112, and an N-type window layer 1114 stacked sequentially. The arrangement of the N-type space layer 1111 and the N-type confinement layer 1112 is related to... Figure 3 The structure is the same as shown. In this optional embodiment, an N-type window layer 1114 is added. The thickness of the N-type window layer 1114 is 200 nm to 10000 nm, and further 300 nm to 10000 nm, 500 nm to 10000 nm, 300 nm to 8000 nm, 500 nm to 8000 nm, etc. The doping concentration of the N-type window layer 1114 is greater than 5.0E+17 atom / cm. 3 The first ohmic contact layer 114 is formed above the N-type window layer 1114. The thickness and doping concentration of the N-type window layer 1114 are conducive to the optimization of the energy band, realizing the forward tunneling current from the N-type window layer 1114 to the P-type first ohmic contact layer 114.
[0078] As described above, in this embodiment, the N-type window layer 1114 can be retained or omitted, and the thickness of the N-type window layer 1114 is adjustable. By adjusting the thickness of the N-type window layer, the overall thickness of the light-emitting diode can be adjusted, thus facilitating adaptation to different product requirements.
[0079] In another optional embodiment of this example, such as Figure 6 As shown, in the direction gradually moving away from the active layer 112 (i.e., Figure 6 In the semiconductor stack 110 (from bottom to top), the N-type semiconductor layer 111 includes an N-type space layer 1111, an N-type confinement layer 1112, an N-type window layer 1114, and a heavily doped layer 1113 formed between the N-type window layer 1114 and the first ohmic contact layer 114, which are stacked sequentially. Figure 5 The N-type window layer 1114 in the structure shown is the same as that described above, and the heavily doped layer 1113 is the same as that described above. Figure 4 The heavily doped layer 1113 in the structure shown is the same. In this optional embodiment, the heavily doped layer 1113 forms a tunnel junction with the first ohmic contact layer 114, which can further reduce the tunneling threshold condition and reduce the operating voltage of the light-emitting diode 100. In addition, the doping concentration of the N-type window layer 1114 is lower than that of the heavily doped layer 1113, thus reducing the absorption of photons by the impurity energy levels of the N-type window layer 1114, which is beneficial to improving the light extraction efficiency.
[0080] Refer again Figures 2 to 6In this embodiment, in the direction gradually moving away from the active layer 112 (i.e., from top to bottom in the figure), the P-type semiconductor layer 113 includes a P-type space layer 1131, a P-type confinement layer 1132, a P-type transition layer 1133, and a P-type window layer 1134 stacked sequentially. The P-type space layer 1131 is, for example, an unintentionally doped AlGaInP layer, the P-type confinement layer 1132 is a P-type doped AlInP layer, the P-type transition layer 1133 is a P-type doped AlGaInP layer, and the P-type window layer 1134 is a P-type GaP layer. The P-type space layer 1131 and the N-type space layer 1111 are symmetrically arranged, which can adjust carrier injection, optimize the distribution of carriers in multiple quantum wells, and also play a role in buffering and controlling the band structure, thereby improving luminescence efficiency. The P-type confinement layer 1132 and the N-type confinement layer 1112 are symmetrically arranged, providing holes to the active layer 112 while preventing electrons from escaping from the light-emitting region to the P-region, effectively confining carriers and improving radiative recombination efficiency. The P-type transition layer 1133 can alleviate lattice constant differences, reduce interface defects, and improve the crystal quality of the semiconductor epitaxial stack 110. The P-type window layer 1134, as a current spreading layer, facilitates lateral current diffusion, allowing the current to be injected more uniformly into the light-emitting layer.
[0081] In this embodiment, the second ohmic contact layer 115 is also a p-type doped material layer, such as a p-type doped GaP layer. This second ohmic contact layer 115 provides good ohmic contact, facilitating the formation of a low-resistance contact between the electrode and the semiconductor. Furthermore, GaP has a large band gap and is transparent to visible light, which helps reduce light absorption and improve light extraction efficiency.
[0082] Refer again Figure 2 The first electrode 121 formed on the side of the first ohmic contact 114 away from the N-type semiconductor layer 111 is a transparent electrode, and further, it is a transparent conductive oxide material layer, such as one or more combinations of ITO, GaP, IZO, IGZO, or AZO. Using a transparent conductive material for the first electrode 121 can further reduce light absorption and improve the light emission effect of the light-emitting diode 100. The second electrode 122 formed on the side of the second ohmic contact 115 away from the P-type semiconductor layer 113 can also be a transparent electrode, for example, it can also be a transparent conductive material layer formed from one or more combinations of ITO, GaP, IZO, IGZO, or AZO.
[0083] like Figure 2As shown, a metal layer 130 may be formed on the side of the second electrode 122 away from the second ohmic contact layer 115. This metal layer 130 can serve as a welding electrode for the second electrode 122, used for subsequent electrical connection with control devices, etc. The metal layer 130 may be, for example, Au, Pt, GeAuNi, Ti, BeAu, GeAu, Al, or ZnAu. In an optional embodiment, the metal layer 130 may also serve as a metal reflector, reflecting light radiated from the semiconductor epitaxial stack 110 to the N-type semiconductor layer 111 for exit.
[0084] Refer again Figure 2 The light-emitting diode 100 of this embodiment further includes an insulating protective layer, specifically, it may include a first insulating layer 141 and a second insulating layer 142. The first insulating layer 141 is formed on the sidewall of the semiconductor epitaxial stack 110, and optionally, it may also be formed simultaneously on the edge region of the light-emitting surface. The second insulating layer 142 covers the first insulating layer 141 and extends from the first insulating layer 141 to cover the sidewall of the second electrode 122 and the metal layer 130. The first insulating layer 141 and the second insulating layer 142 form an opening on one side of the N-type semiconductor layer 111, which exposes the first ohmic contact layer 114. The first electrode 121 is formed into the opening and electrically connected to the first ohmic contact layer 114. After filling the opening, the first electrode 121 extends to the surface of the second insulating layer 142 around the opening and to the sidewall of the light-emitting diode 100. The above-mentioned arrangement of the first electrode 121 realizes electrical connection with the N-type semiconductor layer 111 on the one hand, and facilitates electrical connection with subsequent control devices, etc. on the other hand. The first insulating layer 141 and the second insulating layer 142 can be made of the same material or different materials. For example, they can be SiO2. X SiN X SiO X N Y Al2O3, TiO X Any one or more combinations thereof. The first insulating layer 141 and the second insulating layer 142 can effectively prevent the light-emitting diode 100, especially the semiconductor epitaxial stack 110, from contamination or damage by external moisture, impurities, etc., ensuring the performance reliability and durability of the light-emitting diode 100. In addition, the second insulating layer 142 can also achieve insulation between the first electrode 121 and the second electrode 122, preventing defects such as short circuits between them, and improving the reliability of the light-emitting diode.
[0085] Example 2
[0086] This embodiment provides a light-emitting device, such as... Figure 7As shown, the light-emitting device 200 includes a substrate 210 and a light-emitting unit located above the substrate 210. A device layer 211 and an interconnect layer 212 are formed in the substrate 210. The substrate 210 can be made of semiconductor materials such as silicon, silicon carbide, gallium nitride, germanium, gallium arsenide, and indium phosphide, or non-conductive materials such as glass, plastic, or sapphire wafers. The device layer 211 includes complementary metal oxide semiconductor (CMOS) devices or TFT devices, which can constitute the driving circuit of the light-emitting diode. The light-emitting unit is located above the substrate 210 and electrically connected to the interconnect layer 212. In this embodiment, the light-emitting unit includes any of the light-emitting diodes 100 provided in Embodiment 1 of this application. The specific structure of the light-emitting diode can be referred to the description of Embodiment 1, and will not be repeated here. The light-emitting diode 100 is electrically connected to the interconnect layer 212 through a first electrode 121 and a metal layer 130. Interconnect layer 212 is also electrically connected to the devices in device layer 211, thereby realizing the electrical connection between light-emitting diode 100 and the devices, and the switching control of light-emitting diode 100 can be realized through the devices. Since the light-emitting device includes the light-emitting diode of this application, it also has good light emission effect.
[0087] Example 3
[0088] This embodiment provides a light-emitting device, see [link / reference] Figure 8 The light-emitting device 300 includes a circuit board 301 and a plurality of light-emitting devices 302 electrically connected to the circuit board 301. In this embodiment, the light-emitting devices 302 are the light-emitting devices provided in Embodiment 2. Similarly, Figure 8 As shown, a circuit layer 303 is provided in the circuit board 301, and the light-emitting device 302 is electrically connected to the circuit layer 303. Figure 8 As shown, the light-emitting device 300 may also include a housing 304 to protect the light-emitting device from external contamination or damage, while not affecting the light emission effect of the light-emitting device, thereby improving the light emission effect and display effect of the light-emitting device.
[0089] In summary, the light-emitting diodes, light-emitting devices, and light-emitting apparatuses provided in this application effectively overcome the various shortcomings of the prior art and have high industrial application value.
[0090] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.
Claims
1. A light emitting diode, characterized by, The semiconductor epitaxial stack at least comprises an N-type semiconductor layer, an active layer, a P-type semiconductor layer, a first ohmic contact layer and a second ohmic contact layer, the first ohmic contact layer is formed on a side of the N-type semiconductor layer away from the active layer, the second ohmic contact layer is formed on a side of the P-type semiconductor layer away from the active layer, and the first ohmic contact layer and the second ohmic contact layer are both P-type doped material layers.
2. The light emitting diode of claim 1, wherein, The first ohmic contact layer is a P-type doped AlGaAs layer or AlGaInP layer.
3. The light emitting diode according to claim 1 or 2, characterized in that The P-type doping concentration of the first ohmic contact layer is greater than or equal to 1.0E+19 atom / cm 3 .
4. The light emitting diode according to claim 1 or 2, wherein The P-type doping concentration of the first ohmic contact layer is greater than or equal to 1.0E+20 atom / cm 3 .
5. The light emitting diode of claim 1, wherein, The thickness of the first ohmic contact layer is 10 nm to 500 nm.
6. The light emitting diode of claim 1, wherein, The semiconductor epitaxial stack further comprises a first electrode and a second electrode, the first electrode is formed on a side of the N-type semiconductor layer away from the active layer and in contact with the first ohmic contact layer, and the second electrode is formed on a side of the P-type semiconductor layer away from the active layer and in contact with the second ohmic contact layer, and the first electrode and the second electrode are transparent electrodes.
7. The light emitting diode of claim 1, wherein, The N-type semiconductor layer at least comprises an N-type confinement layer between the active layer and the first ohmic contact layer.
8. The light emitting diode of claim 7, wherein, The thickness of the N-type confinement layer is 200 nm to 1000 nm.
9. The light emitting diode of claim 7, wherein, The N-type semiconductor layer further comprises an N-type window layer between the N-type confinement layer and the first ohmic contact layer.
10. The light emitting diode of claim 9, wherein, The thickness of the N-type window layer is 200 nm to 10000 nm.
11. The light emitting diode of claim 8, wherein, The semiconductor epitaxial stack further comprises a heavily doped layer between the N-type confinement layer and the first ohmic contact layer, the heavily doped layer is an N-type doped material layer, and the doping concentration of the N-type confinement layer is lower than that of the heavily doped layer.
12. The light emitting diode of claim 10, wherein, The semiconductor epitaxial stack further comprises a heavily doped layer between the N-type window layer and the first ohmic contact layer, the heavily doped layer is an N-type doped material layer, and the doping concentration of the N-type window layer is lower than that of the heavily doped layer.
13. The light emitting diode according to claim 11 or 12, characterized in that The thickness of the heavily doped layer is 10 nm to 500 nm.
14. The light emitting diode of claim 13, wherein, The N-type doping concentration of the heavily doped layer is greater than 5.0E+18 atom / cm 3 .
15. The light emitting diode of claim 13, wherein the first and second semiconductor layers are formed of a group III-V compound semiconductor. The heavily doped layer is an N-type doped AlGaAs layer or AlGaInP layer.
16. The light emitting diode of claim 1, wherein, The P-type semiconductor layer at least comprises a P-type window layer and a P-type confinement layer, the P-type confinement layer is above the active layer, and the P-type window layer is between the P-type confinement layer and the second ohmic contact layer.
17. The light emitting diode of claim 6, wherein, The semiconductor epitaxial stack further comprises a metal layer electrically connected to the second electrode on a side of the second electrode away from the semiconductor epitaxial stack.
18. A light-emitting device, characterized in that, The semiconductor epitaxial stack comprises: a substrate, a device layer formed in the substrate, and an interconnection layer formed above the device layer; a light emitting unit above the substrate and electrically connected to the interconnection layer, the light emitting unit comprising the light emitting diode of any one of claims 1 to 17.
19. The light emitting device of claim 18, wherein, The metal layer and the first electrode of the light emitting diode are electrically connected to the interconnection layer.
20. A light emitting device comprising: The light emitting device comprises: a driving substrate; a plurality of light emitting devices arrayed above the driving substrate, the driving substrate being electrically connected to the light emitting devices, and the light emitting devices being the light emitting device of claim 18 or 19.