High antistatic release LED positive polarity epitaxial structure and preparation method thereof

Abstract

The application relates to an LED positive polarity epitaxial structure with high antistatic release and a preparation method thereof, and belongs to the technical field of light emitting diodes. The structure comprises a substrate and buffer layers, DBR layers, N-type limiting layers, N-type blocking layers, N-side first doped layers, N-side second doped layers, active layers, P-side second doped layers, P-side first doped layers, P-type blocking layers, P-type limiting layers and P-type current expansion layers arranged on the substrate in sequence. The application reduces the influence of lattice mismatch and thermal mismatch, reduces the stress existing in epitaxial growth, improves the quality of a multi-quantum well layer, and thus improves the antistatic release performance of the device.

Description

Technical Field

[0001] This invention relates to a high anti-static discharge LED positive electrode epitaxial structure and its preparation method, belonging to the field of light-emitting diode technology. Background Technology

[0002] A light-emitting diode (LED) is a semiconductor electronic component that emits light. In recent years, LEDs have been widely used due to their advantages such as low power consumption, long lifespan, small size, energy saving, and environmental friendliness. For example, they can be used in indoor and outdoor lighting, traffic lights, backlights, and other fields.

[0003] Red LEDs are important light source devices widely used in outdoor lighting and automotive taillights. The red LED chip is the fundamental structure used to fabricate red LEDs. A red LED chip typically includes a substrate and sequentially stacked structures on the substrate, such as a laser beam backer (DBR), an n-type AlInP confinement layer, a light-emitting layer, a p-type AlInP confinement layer, a p-type AlGaInP transition layer, and a p-type GaP ohmic contact layer. As the size decreases, the quantum efficiency significantly decreases, and the peak efficiency shifts towards higher current densities. Due to the large lattice and thermal mismatch between gallium arsenide (GaAs) and its substrate, significant stress occurs during epitaxial growth, resulting in numerous defects and affecting the quality of the multi-quantum-well layer. Furthermore, as the chip size decreases, especially at high current densities, the chip's electrostatic discharge (ESD) resistance weakens. Therefore, improving ESD performance is crucial for efficiency.

[0004] Chinese patent document CN115863500A discloses a method for generating an epitaxial structure of a high-ESD Mini LED, comprising the following steps: S2: growing a first electrostatic discharge layer on a multi-quantum-well active region layer, growing a second electrostatic discharge layer on the first electrostatic discharge layer, and growing a third electrostatic discharge layer on the second electrostatic discharge layer; the Mg doping concentration of the second electrostatic discharge layer is 1.1-5E+16atom / cm3, the Mg doping concentration of the first electrostatic discharge layer is 1.1-5 times that of the third electrostatic discharge layer, and the Mg doping concentration of the second electrostatic discharge layer is 0.1%-2% that of the first electrostatic discharge layer. This method simply uses single-sided doping adjustment, which has limited improvement on the lattice quality of the active region. Therefore, this invention is proposed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high anti-static discharge LED positive polarity epitaxial structure, which reduces the effects of lattice mismatch and thermal mismatch, decreases the stress present during epitaxial growth, and improves the quality of the multi-quantum well layer, thereby enhancing the anti-static discharge performance of the device.

[0006] The present invention also provides a method for preparing the above-mentioned high antistatic discharge LED positive polarity epitaxial structure.

[0007] The technical solution of the present invention is as follows: A high anti-static discharge LED positive polarity epitaxial structure includes a substrate and a buffer layer, a DBR layer, an N-type confinement layer, an N-type barrier layer, an N-side first doped layer, an N-side second doped layer, an active layer, a P-side second doped layer, a P-side first doped layer, a P-type barrier layer, a P-type confinement layer, and a P-type current spreading layer sequentially disposed on the substrate.

[0008] According to a preferred embodiment of the present invention, the buffer layer is a GaAs layer with a thickness of 0.5-0.8 μm; The DBR layer is a periodic structure with alternating AlAs and AlGaAs layers, arranged 14 times, for a total of 28 layers. The thickness of the AlAs layer is 550 Å and the thickness of the AlGaAs layer is 500 Å. The N-type confinement layer is an AIP layer with a thickness of 3000A; The N-type barrier layer is (Al) a Ga 1-a ) 0.5 In 0.5 bPb layer, with a thickness of 1000 Å; The active layer is a periodic structure with alternating well layers and barrier layers. The well layers are GaInP and the barrier layers are AlGaInP. One well layer and one barrier layer constitute one period, and the number of periods is 10-20. The thickness of the active layer is 0.15μm-0.2μm. The P-type barrier layer is (Al) a Ga 1-a ) 0.5 In 0.5 bPb layer, with a thickness of 1000 Å; The P-type confinement layer is an AIP layer with a thickness of 1000A-3000A; The P-type current spreading layer is a gap layer with a thickness of 4.5 μm; The first doped layer on the N-side is (Al) a Ga 1-a ) 0.5 In 0.5 bPb layer, with a thickness of 200 Å; The second doped layer on the N-side is (Al) a Ga 1-a ) 0.5 In 0.5 bPb, with a thickness of 100A; The second doped layer on the P-side is (Al) a Ga 1-a ) 0.5 In0.5 bPb, with a thickness of 100A; The first doped layer on the P-side is (Al) a Ga 1-a ) 0.5 In 0.5 bPb, with a thickness of 200A.

[0009] The preparation method of the above-mentioned LED positive electrode epitaxial structure with high antistatic discharge comprises the following steps: S1: Place the substrate into the reaction chamber of the metal-organic chemical vapor deposition equipment, and grow a buffer layer, a DBR layer, an N-type confinement layer and an N-type barrier layer on the substrate in sequence; S2: Under the growth atmosphere of H2, control the amount of Si2H6 introduced, and grow the first doped layer and the second doped layer on the N-type barrier layer, and continue to grow for 1 minute each. The Si doping concentration of the first doped layer on the N-side is 1-5E+18 atom / cm³. 3 The Si doping concentration of the first doped layer on the N side is 1-5 times that of the second doped layer on the N side; S3: An active layer is grown on the second doped layer on the N-side; S4: Grow the second doped layer on the P-side and the first doped layer on the P-side on the active layer; The Mg doping concentration of the first doped layer on the P-side is 1-5E+17 atom / cm³. 3 The Mg doping concentration of the first doped layer on the P side is 1-5 times that of the second doped layer on the P side. S5: Grow a P-type barrier layer, a P-type confinement layer, and a P-type current spreading layer on the first doped layer on the P-side to complete the fabrication.

[0010] According to a preferred embodiment of the present invention, in step S1, after the substrate is placed into the reaction chamber of the metal-organic chemical vapor deposition equipment, the reaction chamber is purged with hydrogen gas to fill the reaction chamber with hydrogen gas. Then the hydrogen purging is turned off, the reaction chamber pressure is set to 50-60 mbar, the temperature is set to 700-800°C, and the process is continued for 7-10 minutes. The reaction chamber is then purged with hydrogen and ammonia gas, and then growth is carried out.

[0011] According to a preferred embodiment of the present invention, in step S1, the buffer layer growth process specifically comprises: Set the reaction chamber pressure to 50-60 mbar and the temperature to 700-800℃. Simultaneously introduce 100-120 sccm of TMGa and 200-300 sccm of AsH3 into the reaction chamber for 4-6 minutes to grow the buffer layer. The specific process of DBR layer growth is as follows: The reaction chamber pressure is set to 50-60 mbar and the temperature to 700-800℃. Simultaneously, 300-500 sccm of AsH3 and 400-800 sccm of TMAl are introduced into the reaction chamber to grow an AlAs layer. Then, 400-800 sccm of TMAl and 100-200 sccm of TMGa are introduced to grow an AlGaAs layer. This alternating growth is continued for 30-60 minutes to form a DBR layer on the buffer layer.

[0012] The N-type confinement layer growth process is as follows: The AsH3 channel is closed, and simultaneously, 800-1200 sccm of PH3, 300-500 sccm of TMIn, and 150-200 sccm of TMAl are introduced into the reaction chamber. The Si doping concentration is 1-3E+18 atom / cm. 3 This process lasts for 5-15 minutes, forming an N-type confinement layer. The specific process of N-type barrier layer growth is as follows: Maintain PH3 atmosphere ， Introduce 300~500 sccm™In, 150~200 sccm™Al and 30~40 sccm™Ga for 2-5 minutes to form an N-type barrier layer on the N-type confinement layer.

[0013] According to a preferred embodiment of the present invention, in step S3, the active layer growth process specifically comprises: Maintain a pH 3 atmosphere, set the reaction chamber temperature to 700-800 degrees Celsius, and continue for 10-20 minutes to alternately grow the trap layer and barrier layer of the active layer to form the active layer.

[0014] According to a preferred embodiment of the present invention, in step S5, the P-type barrier layer growth process specifically comprises: Set the temperature of the reaction chamber to 700-800℃, maintain pH 3, and introduce 300-500 sccm™ In, 150-200 sccm™ Al and 30-40 sccm™ Ga for 2-5 minutes to form a P-type barrier layer. The specific process of P-type confinement layer growth is as follows: Set the reaction chamber temperature to 700-800℃ and the pressure to 50-60mbar. Introduce 800-1200sccm of PH3, 300-500sccm of TMIn and 150-200sccm of TMAl into the reaction chamber. The doping concentration of Mg is 1-3E+18atom / cm3. Continue for 5-15 minutes to form a P-type confinement layer. The specific process of growing the P-type current-spreading layer is as follows: Set the reaction chamber temperature to 800-1000℃ and the pressure to 50-60 mbar. Introduce 400-800 sccm of PH3 into the reaction chamber, and 300-500 sccm of TMGa. The doping concentration of Mg is 0.5-3E+18 atom / cm³. 3 This process continues for 20-30 minutes, forming a P-type current spread layer.

[0015] The beneficial effects of this invention are as follows: In the diode structure of this invention, the active layer is divided into an N-side and a P-side, which respectively provide electrons and holes. The Si doping source on the N-side provides electrons to the structure, and the Mg doping source on the P-side provides holes to the structure. The N-side and P-side are doped simultaneously, and the doping concentration decreases from the corresponding barrier layer to the active layer. The doping concentration of Mg and Si elements first decreases and then increases. The active layer is undoped, which greatly improves the lattice quality of the active region and has a good effect, significantly improving the high antistatic discharge performance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; The structure includes: 1. Substrate; 2. Buffer layer; 3. DBR layer; 4. N-type confinement layer; 5. N-type barrier layer; 6. First doped layer on the N-side; 7. Second doped layer on the N-side; 8. Active layer; 9. Second doped layer on the P-side; 10. First doped layer on the P-side; 11. P-type barrier layer; 12. P-type confinement layer; 13. P-type current spreading layer. Detailed Implementation

[0017] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto. Example 1:

[0018] This embodiment provides a high anti-static discharge LED positive polarity epitaxial structure, including a substrate 1 and a buffer layer 2, a DBR layer 3, an N-type confinement layer 4, an N-type barrier layer 5, an N-side first doped layer 6, an N-side second doped layer 7, an active layer 8, a P-side second doped layer 9, a P-side first doped layer 10, a P-type barrier layer 11, a P-type confinement layer 12, and a P-type current spreading layer 13 sequentially disposed on the substrate 1.

[0019] The buffer layer is a GaAs layer; the DBR layer is a periodic structure with alternating AlAs and AlGaAs layers, alternating 14 times, for a total of 28 layers. The thickness of the AlAs layer is 550 Å and the thickness of the AlGaAs layer is 500 Å. The N-type confinement layer is an AIP layer with a thickness of 3000A; The N-type barrier layer is (Al) a Ga 1-a )0.5 In 0.5 bPb layer, with a thickness of 1000 Å; The active layer is a periodic structure with alternating well layers and barrier layers. The well layers are GaInP and the barrier layers are AlGaInP. One well layer and one barrier layer constitute one period, and the number of periods is 15. The thickness of the active layer is 0.2 μm. The P-type barrier layer is (Al) a Ga 1-a ) 0.5 In 0.5 bPb layer, with a thickness of 1000 Å; The P-type confinement layer is an AIP layer with a thickness of 1000A-3000A; The P-type current spreading layer is a gap layer with a thickness of 4.5 μm.

[0020] The first doped layer on the N-side is (Al) a Ga 1-a ) 0.5 In 0.5 bPb layer, with a thickness of 200 Å; The second doped layer on the N-side is (Al) a Ga 1-a ) 0.5 In 0.5 bPb, with a thickness of 100A; The second doped layer on the P-side is (Al) a Ga 1-a ) 0.5 In 0.5 bPb, with a thickness of 100A; The first doped layer on the P-side is (Al) a Ga 1-a ) 0.5 In 0.5 bPb, with a thickness of 200A.

[0021] The method for preparing the above-mentioned high anti-static discharge LED positive electrode epitaxial structure includes the following steps: S1: Place the substrate into the reaction chamber of the metal-organic chemical vapor deposition equipment and purge the reaction chamber with hydrogen gas. S2: Set the reaction chamber pressure to 55 mbar and the temperature to 850℃ for 10 minutes.

[0022] S3: Set the reaction chamber pressure to 55 mbar and the temperature to 750 °C. Simultaneously, introduce 120 sccm of TMGa and 220 sccm of AsH3 into the reaction chamber for 6 minutes to grow a buffer layer with a thickness of 0.5 μm on the substrate.

[0023] S4: Set the reaction chamber pressure to 55 mbar and the temperature to 750℃. Simultaneously, introduce 500 sccm of AsH3 and 400 sccm of TMAl into the reaction chamber to grow an AlAs layer. Then, introduce 400 sccm of TMAl and 100 sccm of TMGa to grow an AlGaAs layer. AlgaAs layer is grown alternately for 30-60 minutes to form a DBR layer on the buffer layer.

[0024] S5: Set the reaction chamber pressure to 55 mbar and the temperature to 750℃, close the AsH3 channel, and simultaneously introduce 800 sccm of PH3, 300 sccm of TMIn and 150 sccm of TMAl into the reaction chamber. The Si doping concentration is 1E+18 atom / cm3. Continue for 5 minutes to form an N-type confinement layer.

[0025] S6: Set the reaction chamber pressure to 55 mbar and the temperature to 750℃, maintaining a pH 3 atmosphere. ， An N-type barrier layer is formed on the N-type confinement layer by introducing 300 sccm™In, 150 sccm™Al, and 30 sccm™Ga for 2 minutes.

[0026] S7: Set the reaction chamber pressure to 55 mbar and the temperature to 750℃. Grow the first doped layer and the second doped layer on the N-type barrier layer. Grow each layer for 1 minute. The only difference between the two layers is the order of magnitude of Si doping. The Si doping concentration of the first doped layer on the N-side is 1E+18 atom / cm3, and the Si doping concentration of the first doped layer on the N-side is 5 times that of the second layer. S8: Alternately grow the well layer and barrier layer of the multi-quantum well active region on the second doped layer on the N side, maintain the PH3 atmosphere, set the reaction chamber temperature to 700-800 degrees, and continue for 20 minutes to alternately grow the well layer and barrier layer of the active layer to form the active layer.

[0027] S9: Set the reaction chamber pressure to 55 mbar and the temperature to 750℃. Grow the second doped layer and the first doped layer on the P side on the active layer, and continue growing for 1 minute each. The only difference between the two layers is the order of magnitude of Mg doping. The Mg doping concentration of the first doped layer on the P side is 5E+17 atom / cm3, and the Mg doping concentration of the first doped layer on the P side is 5 times that of the second doped layer on the P side.

[0028] S10: Set the reaction chamber pressure to 55 mbar and the temperature to 750℃, maintain pH 3, and introduce 300 sccm™ In, 150 sccm™ Al and 30 sccm™ Ga for 5 minutes to form a P-type barrier layer.

[0029] S11: Set the reaction chamber pressure to 55 mbar and the temperature to 750℃. Introduce 800 sccm of PH3, 300 sccm of TMIn and 150 sccm of TMAl into the reaction chamber. The doping concentration of Mg is 1.5E+18 atom / cm3. Continue for 5 minutes to form a P-type confinement layer.

[0030] S12: Set the reaction chamber pressure to 55 mbar and the temperature to 850℃. Introduce 400 sccm of PH3 and 300 sccm of TMGa into the reaction chamber. The doping concentration of Mg is 1E+18 atom / cm. 3 This process continues for 20-30 minutes, forming a P-type current spread layer.

[0031] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

[0032] Furthermore, it is understood that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.

Claims

1. A high anti-static discharge LED positive electrode epitaxial structure, characterized in that, It includes a substrate and a buffer layer, a DBR layer, an N-type confinement layer, an N-type barrier layer, an N-side first doped layer, an N-side second doped layer, an active layer, a P-side second doped layer, a P-side first doped layer, a P-type barrier layer, a P-type confinement layer, and a P-type current spread layer sequentially disposed on the substrate. The first doped layer on the N-side is (Al) a Ga 1-a ) 0.5 In 0.5 The P layer has a thickness of 200 Å. The second doped layer on the N-side is (Al) a Ga 1-a ) 0.5 In 0.5 The P layer has a thickness of 100 Å; The second doped layer on the P-side is (Al) a Ga 1-a ) 0.5 In 0.5 The P layer has a thickness of 100 Å; The first doped layer on the P-side is (Al) a Ga 1-a ) 0.5 In 0.5 The P layer has a thickness of 200 Å; The Si doping concentration of the first doped layer on the N-side is 1×10⁻⁶. 18 -5×10 18 atom / cm 3 The Si doping concentration of the first doped layer on the N side is 5 times that of the second doped layer on the N side. The Mg doping concentration of the first doped layer on the P-side is 1×10⁻⁶. 17 -5×10 17 atom / cm 3 The Mg doping concentration of the first doped layer on the P side is 5 times that of the second doped layer on the P side.

2. The LED positive electrode epitaxial structure with high antistatic discharge as described in claim 1, characterized in that, The buffer layer is a GaAs layer with a thickness of 0.5-0.8 μm; The DBR layer is a periodic structure with alternating AlAs and AlGaAs layers, arranged 14 times, for a total of 28 layers. The thickness of the AlAs layer is 550 Å and the thickness of the AlGaAs layer is 500 Å. The N-type confinement layer is an AlP layer with a thickness of 3000 Å; The N-type barrier layer is (Al) a Ga 1-a ) 0.5 In 0.5 The P layer has a thickness of 1000 Å; The active layer is a periodic structure with alternating well layers and barrier layers. The well layers are GaInP and the barrier layers are AlGaInP. One well layer and one barrier layer constitute one period, and the number of periods is 10-20. The thickness of the active layer is 0.15μm-0.2μm. The P-type barrier layer is (Al) a Ga 1-a ) 0.5 In 0.5 The P layer has a thickness of 1000 Å; The P-type confinement layer is an AlP layer with a thickness of 1000 Å-3000 Å; The P-type current spreading layer is a GaP layer with a thickness of 4.5 μm.

3. The method for preparing the LED positive electrode epitaxial structure with high antistatic discharge as described in claim 2, characterized in that, The steps are as follows: S1: Place the substrate into the reaction chamber of the metal-organic chemical vapor deposition equipment, and grow a buffer layer, a DBR layer, an N-type confinement layer and an N-type barrier layer on the substrate in sequence; S2: Under the growth atmosphere of H2, control the amount of Si2H6 introduced, and grow the first doped layer and the second doped layer on the N-type barrier layer, and continue to grow for 1 minute each. S3: An active layer is grown on the second doped layer on the N-side; S4: Grow the second doped layer and the first doped layer on the P side on the active layer; S5: Grow a P-type barrier layer, a P-type confinement layer, and a P-type current spreading layer on the first doped layer on the P-side to complete the fabrication.

4. The method for preparing the LED positive electrode epitaxial structure with high antistatic discharge as described in claim 3, characterized in that, In step S1, after placing the substrate into the reaction chamber of the metal-organic chemical vapor deposition equipment, the reaction chamber is purged with hydrogen gas to fill it with hydrogen gas. Then the hydrogen purging is turned off, the reaction chamber pressure is set to 50-60 mbar, the temperature is set to 700-800℃, and this is continued for 7-10 minutes. The reaction chamber is then purged with hydrogen and ammonia gas before growth is carried out.

5. The method for preparing the LED positive electrode epitaxial structure with high antistatic discharge as described in claim 3, characterized in that, In step S1, the buffer layer growth process is as follows: Set the reaction chamber pressure to 50-60 mbar and the temperature to 700-800℃. Simultaneously introduce 100-120 sccm of TMGa and 200-300 sccm of AsH3 into the reaction chamber for 4-6 minutes to grow the buffer layer. The specific process of DBR layer growth is as follows: The reaction chamber pressure is set to 50-60 mbar and the temperature to 700-800℃. Simultaneously, 300-500 sccm of AsH3 and 400-800 sccm of TMAl are introduced into the reaction chamber to grow an AlAs layer. Then, 400-800 sccm of TMAl and 100-200 sccm of TMGa are introduced to grow an AlGaAs layer. This alternating growth is carried out for 30-60 minutes to form a DBR layer on the buffer layer. The N-type confinement layer growth process is as follows: The AsH3 channel is closed, and simultaneously, 800-1200 sccm of PH3, 300-500 sccm of TMIn, and 150-200 sccm of TMAl are introduced into the reaction chamber. The Si doping concentration is 1×10⁻⁶. 18 -3×10 18 atom / cm 3 This process lasts for 5-15 minutes, forming an N-type confinement layer. The specific process of N-type barrier layer growth is as follows: Maintain PH3 atmosphere ， Introduce 300~500 sccm™In, 150~200 sccm™Al and 30~40 sccm™Ga for 2-5 minutes to form an N-type barrier layer on the N-type confinement layer.

6. The method for preparing the LED positive electrode epitaxial structure with high antistatic discharge as described in claim 3, characterized in that, In step S3, the active layer growth process is as follows: Maintain a pH 3 atmosphere, set the reaction chamber temperature to 700-800 degrees Celsius, and continue for 10-20 minutes to alternately grow the trap layer and barrier layer of the active layer to form the active layer.

7. The method for preparing the LED positive electrode epitaxial structure with high antistatic discharge as described in claim 3, characterized in that, In step S5, the P-type barrier layer growth process is as follows: Set the temperature of the reaction chamber to 700-800℃, maintain pH 3, and introduce 300-500 sccm™ In, 150-200 sccm™ Al and 30-40 sccm™ Ga for 2-5 minutes to form a P-type barrier layer.

8. The method for preparing the LED positive electrode epitaxial structure with high antistatic discharge as described in claim 3, characterized in that, In step S5, the P-type confinement layer growth process is as follows: Set the reaction chamber temperature to 700-800℃ and the pressure to 50-60 mbar. Introduce 800-1200 sccm of PH3, 300-500 sccm of TMIn, and 150-200 sccm of TMAl into the reaction chamber. The Mg doping concentration is 1×10⁻⁶. 18 -3×10 18 atom / cm 3 This process lasts for 5-15 minutes, forming a P-type confinement layer.

9. The method for preparing the LED positive electrode epitaxial structure with high antistatic discharge as described in claim 3, characterized in that, In step S5, the P-type current spreading layer growth process is as follows: The reaction chamber temperature is set to 800-1000℃, and the pressure to 50-60 mbar. 400-800 sccm of PH3 is introduced into the reaction chamber, along with 300-500 sccm of TMGa. The doping concentration of Mg is 0.5 × 10⁻⁶. 18 -3×10 18 atom / cm 3 This process continues for 20-30 minutes, forming a P-type current spread layer.

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