Infrared LED epitaxial wafer for remote controller and preparation method thereof

Abstract

The application relates to the technical field of LEDs, in particular to an infrared LED epitaxial wafer for a remote controller and a preparation method thereof. The infrared LED epitaxial wafer comprises, from bottom to top, a GaAs substrate, an N-type GaAs buffer layer, an N-type current expansion layer, an N-type limiting layer, a multi-quantum well light-emitting layer, a P-type limiting layer, a P-type inner reflection light-gathering layer, a P-type current expansion layer, a high-voltage response layer and a P-type contact layer. The P-type inner reflection light-gathering layer and the high-voltage response layer are designed in the conventional infrared LED epitaxial structure, so that the radiation light intensity, the light-emitting angle and the response current of the infrared LED for the remote controller can be improved, and the control distance of the remote controller is improved.

Description

Technical Field

[0001] This invention relates to the field of LED technology, specifically to an infrared LED epitaxial wafer for remote control and its preparation method. Background Technology

[0002] LEDs (light-emitting diodes), as a new generation of lighting source, have high luminous intensity, low operating voltage, small size, long lifespan, and are easy to package. Therefore, LED light sources have the characteristics of energy saving, environmental protection, and long lifespan. For non-visible light infrared LEDs, due to their specific wavelength, low power consumption, and high reliability, they are widely used in remote control, security monitoring, wearable devices, space communication, medical devices, sensors, and other fields.

[0003] With the development and widespread adoption of high-end home appliances, higher demands are being placed on the response characteristics, light power specifications, sensitivity, and lifespan of appliance remote controls. Conventional infrared LEDs in the industry have epitaxial structures such as... Figure 1 As shown, the epitaxial layers are grown starting from the GaAs substrate 100, and from bottom to top are: an N-type GaAs buffer layer 101, an N-type current spreading layer 102, an N-type confinement layer 103, a multi-quantum-well emitting layer 104, a P-type confinement layer 105, a P-type current spreading layer 106, and a P-type contact layer 107. When driven by a constant voltage power supply, the stable series resistance of the epitaxial material itself prevents the generation of a high response current, indirectly resulting in low current density and low luminous power, thus failing to achieve high radiant light intensity. Furthermore, due to the difference in refractive index between GaAs and air in the surface contact layer of conventional infrared LEDs, the emission angle is highly dispersed and the focusing characteristics are poor, resulting in weak light intensity at zero degrees of normal. This shortens the receiving and control distance of the remote control, failing to meet the application scenarios of many products. Based on the aforementioned shortcomings of conventional infrared LEDs, such as dispersed emission angles, low response current, and low radiant light intensity, they often fail to meet the application requirements of high-end home appliance remote controls. Therefore, improving the emission angle, response current, and radiant intensity of infrared LEDs driven by constant voltage power supplies is urgently needed for the high-end remote control market. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an infrared LED epitaxial wafer for remote controls and its fabrication method. This infrared LED epitaxial wafer for remote controls can effectively solve the problems of discrete light emission angle, poor light focusing characteristics, and low radiation intensity of conventional infrared LEDs when driven by a constant voltage power supply, thereby improving the control distance of the remote control and expanding the application fields of the product.

[0005] The first object of the present application is to provide an infrared LED epitaxial wafer for remote controller, which comprises GaAs substrate, N-type GaAs buffer layer, N-type current spreading layer, N-type confinement layer, multi-quantum well light emitting layer, P-type confinement layer, P-type internal reflection concentrator, P-type current spreading layer, high voltage response layer and P-type contact layer from bottom to top.

[0006] The P-type internal reflection concentrator is a periodic structure of P-type AlAs / (Al x3 Ga 1-x3 ) 0.5 In 0.5 P materials, wherein x3 is in the range of 0.7-0.8.

[0007] The high voltage response layer is a structure of high-doped (Al x1 Ga 1-x1 ) 0.5 In 0.5 P material, low-doped Al 0.5 In 0.5 P material and high-doped (Al x2 Ga 1-x2 ) 0.5 In 0.5 P material, wherein x1 and x2 are in the range of 0.3-0.6.

[0008] The present application introduces a functional epitaxial structure of periodic growth of materials with high and low refractive index difference between the P-type confinement layer and the P-type spreading layer, so that the photons outputted by the light emitting layer can be internally reflected at the heterojunction interface with high and low refractive index difference, and the light source with large angle is suppressed to escape, thereby most of the light is collected in the normal direction perpendicular to the chip, and the radiant intensity of the infrared LED for remote controller is improved; the high voltage response layer is introduced between the P-type current spreading layer and the P-type contact layer, which is an epitaxial layer with high potential barrier and lattice matching with GaAs material of the infrared LED by using AlGaInP quaternary system material, so as to improve the response output current of the infrared LED under constant voltage power supply, generate more carriers, and improve the problems of insufficient current density and low overall radiation intensity of the conventional infrared LED under constant voltage power supply.

[0009] Further, the thickness of AlAs in each periodic structure is 25-30 nm, Cp2Mg is used as the P-type dopant, and the doping concentration is 2×10 18 cm -3 -3×10 18 cm -3 ; and the thickness of (Al x3 Ga 1-x3 ) in each periodic structure is 25-30 nm, Cp2Mg is used as the P-type dopant, and the doping concentration is 2×100.5 In 0.5 The thickness of P is 40nm–50nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 1×10⁻⁶. 18 cm -3 ~2×10 18 cm -3 The principle behind designing the P-type internal reflection focusing layer in this technical solution is: utilizing AlAs and (Al... x3 Ga 1-x3 ) 0.5 In 0.5 The poor refractive index of P materials, coupled with the abrupt junction barrier at the heterojunction interface of arsenides and phosphides, causes the light emitted by the infrared LED to penetrate AlAs and (Al... x3 Ga 1-x3 ) 0.5 In 0.5 Internal reflection occurs at the P interface, meaning that light at large angles cannot pass through the epitaxial layer into the outside air through refraction. Instead, it undergoes multiple internal reflections within the epitaxial structure and is focused onto a direction perpendicular to the LED chip, thereby enhancing the intensity of normal radiation. Furthermore, the abrupt junction barrier in each cycle facilitates the lateral expansion of high current density in constant voltage power supply driving, preventing issues such as junction temperature rise and aging failure in infrared LEDs, thus improving LED reliability.

[0010] Furthermore, the number of cycle pairs in the periodic structure is 6 to 10 pairs.

[0011] Furthermore, the highly doped (Al) x1 Ga 1-x1 ) 0.5 In 0.5 The thickness of the P-material is 100 nm to 200 nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 .

[0012] Furthermore, the low-doped Al 0.5 In 0.5 The thickness of the P-type material is 50 nm to 100 nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 0.5 × 10⁻⁶. 18 cm -3 ~1×10 18 cm -3 .

[0013] Furthermore, the highly doped (Al) x2 Ga 1-x2 ) 0.5 In0.5 The thickness of the P-material is 100 nm to 200 nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 .

[0014] The principle behind designing the high-voltage response layer in this technical solution is as follows: When driven by a constant voltage power supply, the introduced high-voltage response layer can build a dam-like, stepped Schottky barrier between the conventional current spread layer and the contact layer, helping the current to converge in this region and also having a voltage-dividing effect. Utilizing highly doped (Al) x1 Ga 1-x1 ) 0.5 In 0.5 P and (Al) x2 Ga 1-x2 ) 0.5 In 0.5 P has a higher electron mobility than Al. 0.5 In 0.5 The properties of P material ensure that a large amount of current flows through Al during constant voltage power supply operation. 0.5 In 0.5 The P-layer is generated and then radiatively recombines with the light-emitting layer through the current spreading layer. Therefore, the high-voltage response layer of this invention can significantly increase the response current of infrared LEDs driven by a constant voltage power supply, ensuring that a large number of electrons and holes are generated to participate in radiative recombination, thereby improving the overall radiant light intensity of the device.

[0015] The second objective of this invention is to provide a method for fabricating an infrared LED epitaxial wafer for a remote control. The method involves using an MOCVD (metal-organic chemical vapor deposition) device to grow, from bottom to top, an N-type GaAs buffer layer, an N-type current spreading layer, an N-type confinement layer, a multi-quantum well light-emitting layer, a P-type confinement layer, a P-type internal reflection focusing layer, a P-type current spreading layer, a high-voltage response layer, and a P-type contact layer on a GaAs substrate.

[0016] Furthermore, the growth steps of the P-type internal reflection concentrator layer are as follows: The reaction chamber temperature is set to 680℃±10℃; TMAl and AsH3 source materials are introduced into the P-type confinement layer, and Cp2Mg is introduced simultaneously as a dopant to grow AlAs material with a thickness of 25nm~30nm. The flow rate of Cp2Mg is set to 30sccm~60sccm, and the doping concentration is 2×10⁻⁶. 18 cm -3 ~3×10 18 cm -3 Then, turn off AsH3 and introduce TMGa, TMIn, and PH3 to grow Al₂O₃ with a thickness of 40nm–50nm. x3 Ga 1-x3) 0.5 In 0.5 For the P material, the set flow rate of Cp2Mg is 50 sccm to 100 sccm, and the doping concentration is 1 × 10⁻⁶. 18 cm -3 ~2×10 18 cm -3 The above co-doped AlAs and (Al x3 Ga 1-x3 ) 0.5 In 0.5 The P-grown combination forms the first pair of internal reflection focusing layers, and then the combination structure is repeated 5 to 9 times.

[0017] Furthermore, TMAl, TMGa, TMIn, and PH3 are introduced into the P-type current-spreading layer to grow an Al layer with a thickness of 100 nm to 200 nm. x1 Ga 1-x1 ) 0.5 In 0.5 P-type material was used, with Cp₂Mg as the P-type dopant. The set flux of Cp₂Mg was 150 sccm to 200 sccm, and the doping concentration was 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 Then, TMGa was turned off, and Al with a thickness of 50 nm to 100 nm was grown. 0.5 In 0.5 For the P material, the set flow rate of Cp2Mg is 20 sccm to 50 sccm, and the doping concentration is 0.5 × 10⁻⁶. 18 cm -3 ~1×10 18 cm -3 Then continue to introduce TMGa to grow Al1 with a thickness of 100nm to 200nm. x2 Ga 1-x2 ) 0.5 In 0.5 For the P material, the set flow rate of Cp2Mg is 150 sccm to 200 sccm, and the doping concentration is 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 .

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This invention employs a P-type internal reflection focusing layer and a high-voltage response layer in the conventional infrared LED epitaxial structure. On one hand, the P-type internal reflection focusing layer structure allows photons emitted from the light-emitting layer to undergo internal reflection at the interface of the heterojunction with high and low refractive indices, suppressing large-angle light emission and concentrating most of the light at zero degrees perpendicular to the chip's normal. This increases the radiant light intensity of the infrared LED used in remote controls and facilitates the lateral expansion of high current density in constant-voltage power supply driving, reducing chip heat generation and improving the reliability of the infrared LED. On the other hand, the high-voltage response layer significantly increases the response current of the infrared LED under constant-voltage power supply driving, ensuring the generation of a large number of electrons and holes to participate in radiative recombination, thereby improving the overall radiant light intensity of the device. The combination of these two features effectively solves the problems of discrete emission angle, poor focusing characteristics, and low radiant light intensity of conventional infrared LEDs, increasing the control distance of the remote control. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a conventional infrared LED epitaxial wafer;

[0021] Figure 2 This is a schematic diagram of the structure of the infrared LED epitaxial wafer for the remote control of the present invention;

[0022] Figure 3 This is a spatial distribution curve of the light intensity of the infrared LED used in the remote control of this invention;

[0023] Figure 4 This is a spatial distribution curve of the light intensity of a conventional infrared LED.

[0024] Explanation of the labels in the diagram:

[0025] 100. GaAs substrate; 101. N-type GaAs buffer layer; 102. N-type current spreading layer; 103. N-type confinement layer; 104. Multi-quantum well light-emitting layer; 105. P-type confinement layer; 106. P-type current spreading layer; 107. P-type contact layer; 108. P-type internal reflection focusing layer; 109. High voltage response layer. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0027] In the description of this application, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0028] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0029] Please see Figures 1 to 4 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the shape, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0030] One embodiment of the present invention provides an infrared LED epitaxial wafer for a remote control, the structural schematic diagram of which is shown below. Figure 2 As shown, in accordance with the epitaxial growth sequence, from bottom to top, the layers are GaAs substrate 100, N-type GaAs buffer layer 101, N-type current spreading layer 102, N-type confinement layer 103, multi-quantum well light-emitting layer 104, P-type confinement layer 105, P-type internal reflection focusing layer 108, P-type current spreading layer 106, high voltage response layer 109, and P-type contact layer 107.

[0031] In some specific embodiments, the P-type internal reflection focusing layer is composed of AlAs / (Al x3 Ga 1-x3 ) 0.5 In 0.5 The alternating periodic structures of P-material are constructed, with each periodic structure containing AlAs with a thickness of 25 nm to 30 nm. Cp₂Mg is used as the P-type dopant with a doping concentration of 2 × 10⁻⁶. 18 cm -3 ~3×10 18 cm -3 In each periodic structure (Al) x3 Ga 1-x3 ) 0.5 In 0.5The thickness of P is 40nm–50nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 1×10⁻⁶. 18 cm -3 ~2×10 18 cm -3 The value of x3 ranges from 0.7 to 0.8; the number of alternating growth cycles is 6 to 10 pairs. The P-type internal reflection concentrator layer introduced in this invention utilizes AlAs and (Al x3 Ga 1-x3 ) 0.5 In 0.5 The poor refractive index of P materials, coupled with the abrupt junction barrier at the heterojunction interface of arsenides and phosphides, causes the light emitted by the infrared LED to penetrate AlAs and (Al... x3 Ga 1-x3 ) 0.5 In 0.5 Internal reflection is formed at the interface of P, thereby enhancing the intensity of normal radiation.

[0032] In some specific embodiments, the high-voltage response layer is composed of highly doped (Al) x1 Ga 1-x1 ) 0.5 In 0.5 P-materials, lightly doped Al 0.5 In 0.5 P-materials, highly doped (Al) x2 Ga 1-x2 ) 0.5 In 0.5 The epitaxial structure formed by the combination of P materials, wherein the values ​​of x1 and x2 are both in the range of 0.3 to 0.6.

[0033] In some specific embodiments, highly doped (Al) x1 Ga 1-x1 ) 0.5 In 0.5 P is a highly doped layer preferentially grown near the P-type current spreading layer, with a thickness of 100 nm to 200 nm. This layer uses Cp₂Mg as the P-type dopant with a doping concentration of 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 .

[0034] In some specific embodiments, low-doped Al 0.5 In 0.5 P is then highly doped (Al) x1 Ga 1-x1 ) 0.5 In 0.5 P was subsequently grown, followed by low-doped Al. 0.5 In 0.5The thickness of the P-material is 50 nm to 100 nm. This layer uses Cp₂Mg as the P-type dopant with a doping concentration of 0.5 × 10⁻⁶. 18 cm -3 ~1×10 18 cm -3 .

[0035] In some specific embodiments, highly doped (Al) x2 Ga 1-x2 ) 0.5 In 0.5 P was grown last, with a thickness of 100 nm to 200 nm. This layer used Cp₂Mg as the p-type dopant with a doping concentration of 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 This invention introduces a high-voltage response layer structure design. It utilizes the lattice matching between AlGaInP quaternary materials and GaAs-based materials in infrared LEDs, while simultaneously modulating a high-barrier epitaxial layer as a current-collecting region. This enhances the response output current of the infrared LED under constant voltage power supply, generates more charge carriers, and improves the problems of insufficient current density and low overall radiation intensity of conventional infrared LEDs under constant voltage power supply operation.

[0036] In another embodiment, the present invention also provides a method for fabricating an infrared LED epitaxial wafer for a remote control. Using an MOCVD apparatus, an N-type GaAs buffer layer, an N-type current spreading layer, an N-type confinement layer, a multiple quantum well light-emitting layer, a P-type confinement layer, a P-type internal reflection focusing layer, a P-type current spreading layer, a high-voltage response layer, and a P-type contact layer are grown sequentially from bottom to top on a GaAs substrate. Specifically, the method includes the following steps:

[0037] (1) MOCVD was pumped to a low pressure of 50 mbar in a pure H2 atmosphere, and the reaction chamber was set to a temperature of 400 °C. Then, the GaAs substrate was transferred to the reaction chamber by a robotic hand transfer chamber, and then the temperature was rapidly increased to 730 °C and held at 730 °C for 5 min.

[0038] (2) Growth of N-type GaAs buffer layer: The reaction chamber temperature was set to 680℃±10℃, and TMGa and AsH3 were introduced to grow a GaAs buffer layer material with a thickness of 100nm~300nm. SiH4 was used as the N-type dopant with a doping concentration of 3×10 18 cm -3 ~5×10 18 cm -3 .

[0039] (3) Growth of N-type current-extended layer: The reaction chamber temperature was set to 680℃±10℃, and TMGa, TMAl, and AsH3 were introduced to grow an Al layer with a thickness of 3000nm~4000nm. y1 Ga 1-y1 As material, y1 ranges from 0.1 to 0.2, and SiH4 is used as the N-type dopant with a doping concentration of 0.7 × 10⁻⁶. 18 cm -3 ~1.5×10 18 cm -3 .

[0040] (4) Growth of N-type confinement layer: Set the temperature of the reaction chamber to 680℃±10℃, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 400nm~500nm. y2 Ga 1-y2 The material is As, where the value of y2 ranges from 0.25 to 0.60, and SiH4 is used as the N-type dopant with a doping concentration of 2 × 10⁻⁶. 18 cm -3 ~3×10 18 cm -3 .

[0041] (5) Growth of a multi-quantum-well light-emitting layer: The reaction chamber temperature was set to 660℃±10℃, and TMAl, TMGa, TMIn, AsH3, and PH3 were introduced. The growth wells and barriers were In, respectively. y3 Ga 1-y3 As、(Al y4 Ga 1-y4 ) 0.5 As 0.5 The periodic cyclic structure of P material. Among them, the monolayer quantum well In... y3 Ga 1-y3 The thickness of As is 7nm to 9nm, and the value of y3 ranges from 0.15 to 0.18. (Al) is a single-layer quantum barrier. y4 Ga 1-y4 ) 0.5 As 0.5 The thickness of P is 24 nm to 30 nm, and the value of y4 ranges from 0.15 to 0.25. The number of periodic cycles is 8 to 12 pairs, and both the wells and barriers are undoped.

[0042] (6) Growth of P-type confinement layer: Set the reaction chamber temperature to 680℃±10℃, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 500nm~600nm. y5 Ga 1-y5 The material is As, where the value of y5 ranges from 0.25 to 0.60, and CCl4 is used as the p-type dopant with a doping concentration of 2 × 10⁻⁶.18 cm -3 ~3×10 18 cm -3 .

[0043] (7) Growth of P-type internal reflection concentrator layer: The reaction chamber temperature is set to 680℃±10℃. TMAl and AsH3 source materials are introduced into the P-type confinement layer, and Cp2Mg is introduced as a dopant to grow AlAs material with a thickness of 25nm~30nm. The flow rate of Cp2Mg is set to 30sccm~60sccm, and the doping concentration is 2×10⁻⁶. 18 cm -3 ~3×10 18 cm -3 Then, turn off AsH3 and introduce TMGa, TMIn, and PH3 to grow Al₂O₃ with a thickness of 40nm–50nm. x3 Ga 1-x3 ) 0.5 In 0.5 For the P material, the set flow rate of Cp2Mg is 50 sccm to 100 sccm, and the doping concentration is 1 × 10⁻⁶. 18 cm -3 ~2×10 18 cm -3 The value of x3 ranges from 0.7 to 0.8. The above co-doped AlAs and (Al... x3 Ga 1-x3 ) 0.5 In 0.5 The P-grown combination forms the first pair of internal reflection focusing layers, and then the cycle is repeated 5 to 9 times for this combination structure.

[0044] (8) Growth of P-type current-extended layer: The reaction chamber temperature is set to 680℃±10℃, and TMGa, TMAl, and AsH3 are introduced to grow Al with a thickness of 6000nm~8000nm. y6 Ga 1-y6 For As material, the value of y6 ranges from 0.1 to 0.2, and CCl4 is used as the p-type dopant with a doping concentration of 0.5 × 10⁻⁶. 18 cm -3 ~2×10 18 cm -3 .

[0045] (9) Growth of a high-voltage response layer: The reaction chamber temperature is set to 680℃±10℃. TMAl, TMGa, TMIn, and PH3 are introduced into the P-type current-spreading layer to grow a (Al) layer with a thickness of 100nm~200nm. x1 Ga 1-x1 ) 0.5 In 0.5The P-material uses Cp₂Mg as the P-type dopant, with a Cp₂Mg flux of 150 sccm–200 sccm, x₁ ranging from 0.3 to 0.6, and a doping concentration of 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 Then, TMGa was turned off, and Al with a thickness of 50 nm to 100 nm was grown. 0.5 In 0.5 For the P material, the set flow rate of Cp2Mg is 20 sccm to 50 sccm, and the doping concentration is 0.5 × 10⁻⁶. 18 cm -3 ~1×10 18 cm -3 Then continue to introduce TMGa to grow Al1 with a thickness of 100nm to 200nm. x2 Ga 1-x2 ) 0.5 In 0.5 For P-material, the set flow rate of Cp2Mg is 150 sccm to 200 sccm, the value of x2 ranges from 0.3 to 0.6, and the doping concentration is 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 .

[0046] (10) Growth of P-type contact layer: The reaction chamber temperature was set to 650℃±10℃, and TMGa and AsH3 were introduced to grow GaAs contact layer material with a thickness of 60nm~100nm. CCl4 was used as the P-type dopant with a doping concentration of 0.5×10 20 cm -3 ~2×10 20 cm -3 .

[0047] (11) Take out the wafer: After the growth is completed, reduce the temperature of the MOCVD reaction chamber to 110°C, then adjust the pressure to 1000 mbar, open the reaction chamber and take out the epitaxial wafer.

[0048] To further illustrate the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0049] Example 1

[0050] A method for fabricating an epitaxial wafer of an infrared LED for a remote control specifically includes the following steps:

[0051] (1) MOCVD was pumped to a low pressure of 50 mbar in a pure H2 atmosphere, and the reaction chamber was set to a temperature of 400 °C. Then, the GaAs substrate was transferred to the reaction chamber by a robotic hand transfer chamber, and then the temperature was rapidly increased to 730 °C and held at 730 °C for 5 min.

[0052] (2) Growth of N-type GaAs buffer layer: The reaction chamber temperature was set to 680℃, and TMGa and AsH3 were introduced to grow a GaAs buffer layer material with a thickness of 300nm. SiH4 was used as the N-type dopant with a doping concentration of 5×10⁻⁶. 18 cm -3 .

[0053] (3) Growth of N-type current-extended layer: The reaction chamber temperature was set to 680℃, and TMGa, TMAl, and AsH3 were introduced to grow an Al layer with a thickness of 4000 nm. 0.1 Ga 0.9 As material, using SiH4 as the N-type dopant, with a doping concentration of 1.5 × 10⁻⁶. 18 cm -3 .

[0054] (4) Growth of N-type confinement layer: The reaction chamber temperature is set to 680℃, and TMGa, TMAl, and AsH3 are introduced to grow an Al layer with a thickness of 500nm. 0.3 Ga 0.7 As material, using SiH4 as the N-type dopant, with a doping concentration of 2×10⁻⁶. 18 cm -3 .

[0055] (5) Growth of a multi-quantum-well light-emitting layer: The reaction chamber is set to a temperature of 660℃, and TMAl, TMGa, TMIn, AsH3, and PH3 are introduced. The growth wells and barriers are In, respectively. 0.17 Ga 0.83 As、(Al 0.2 Ga 0.8 ) 0.5 As 0.5 The periodic cyclic structure of P material, in which a single-layer quantum well In 0.17 Ga 0.83 The thickness of As is 9 nm, a single-layer quantum barrier (Al 0.2 Ga 0.8 ) 0.5 As 0.5 The thickness of P is 28 nm, the number of cycle pairs is 10, and both the wells and barriers are undoped.

[0056] (6) Growth of P-type confinement layer: The reaction chamber temperature is set to 680℃, and TMGa, TMAl, and AsH3 are introduced to grow an Al layer with a thickness of 500nm. 0.3 Ga0.7 As material, using CCl4 as the p-type dopant, with a doping concentration of 2 × 10⁻⁶. 18 cm -3 .

[0057] (7) Growth of P-type internal reflection focusing layer: The reaction chamber temperature is set to 680℃. TMAl and AsH3 source materials are introduced into the P-type confinement layer, and Cp2Mg is introduced as a dopant to grow AlAs material with a thickness of 30nm. The flow rate of Cp2Mg is set to 50sccm, and the doping concentration is 2×10⁻⁶. 18 cm -3 Then, AsH3 was turned off, and TMGa, TMIn, and PH3 were introduced to grow an Al₂O₃ substrate with a thickness of 48 nm. 0.72 Ga 0.28 ) 0.5 In 0.5 The P material, Cp₂Mg, has a set flux of 70 sccm and a doping concentration of 1.3 × 10⁻⁶. 18 cm -3 The above co-doped AlAs and (Al 0.72 Ga 0.28 ) 0.5 In 0.5 P grows the combination to form the first pair of internal reflection focusing layers, and then repeats cycle 8 for this combination structure.

[0058] (8) Growth of P-type current-spreading layer: The reaction chamber temperature was set to 680℃, and TMGa, TMAl, and AsH3 were introduced to grow an Al layer with a thickness of 7600nm. 0.18 Ga 0.82 As material, using CCl4 as the p-type dopant with a doping concentration of 1.8 × 10⁻⁶. 18 cm -3 .

[0059] (9) Growth of a high-voltage response layer: The reaction chamber temperature was set to 680℃, and TMAl, TMGa, TMIn, and PH3 were introduced into the P-type current-spreading layer to grow a 120nm thick Al layer. 0.35 Ga 0.65 ) 0.5 In 0.5 The material is P, and this layer uses Cp2Mg as the P-type dopant. The set flux of Cp2Mg is 170 sccm, and the doping concentration is 2.1 × 10⁻⁶. 18 cm -3 Then, TMGa was turned off, and Al with a thickness of 80 nm was grown. 0.5 In 0.5 P material, Cp2Mg with a set flux of 40 sccm and a doping concentration of 0.85 × 10⁻⁶ 18 cm-3 Then, TMGa is continued to be introduced to grow an Al₂O₃ layer with a thickness of 150 nm. 0.4 Ga 0.6 ) 0.5 In 0.5 P material, Cp2Mg, set flow rate 180 sccm, doping concentration 2.3 × 10⁻⁶ 18 cm -3 .

[0060] (10) Growth of P-type contact layer: The reaction chamber temperature was set to 650℃, and TMGa and AsH3 were introduced to grow a GaAs contact layer material with a thickness of 80nm. CCl4 was used as the P-type dopant with a doping concentration of 1.2×10⁻⁶. 20 cm -3 .

[0061] (11) Take out the wafer: After the growth is completed, reduce the temperature of the MOCVD reaction chamber to 110°C, then adjust the pressure to 1000 mbar, open the reaction chamber and take out the epitaxial wafer.

[0062] Comparative Example 1

[0063] A conventional infrared LED epitaxial wafer, fabricated using conventional methods, has the following structural schematic diagram: Figure 1 As shown.

[0064] Test case

[0065] The infrared LEDs obtained in Example 1 and Comparative Example 1 were tested under constant voltage power supply. The radiated light intensity and diffusion angles at different intensities were compared. The results are shown in Table 1. Meanwhile, the spatial distribution curves of the light intensity test are shown in the figures below. Figure 3 and Figure 4 As shown.

[0066] Table 1. Comparison of radiation intensity and diffusion angle at different intensities

[0067]

[0068] The test results show that the diffusion angles of the infrared LED used in the remote control prepared by this invention are significantly smaller than those of conventional infrared LEDs. When the diffusion angle is 10%, the diffusion angle of Example 1 is 50.18°, while that of Comparative Example 1 is 66.43°. Example 1 of this invention has a 24% smaller diffusion angle, and the light concentration is better focused at the normal zero-degree angle. The spatial distribution diagram of the light intensity also clearly shows that the light intensity distribution of the infrared LED of this invention is more concentrated, significantly improving the dispersion of the light source. Furthermore, the zero-degree radiation intensity test shows that the radiation intensity of the infrared LED of Example 1 of this invention is 25.89 mW / sr, which is 41.9% higher than the 18.24 mW / sr of the infrared LED of Comparative Example 1, further demonstrating that the technical solution of this invention has a significant improvement effect on the radiation intensity.

[0069] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An infrared LED epitaxial wafer for a remote control, characterized in that, The infrared LED epitaxial wafer comprises, from bottom to top, a GaAs substrate, an N-type GaAs buffer layer, an N-type current spreading layer, an N-type confinement layer, a multi-quantum-well light-emitting layer, a P-type confinement layer, a P-type internal reflection focusing layer, a P-type current spreading layer, a high-voltage response layer, and a P-type contact layer. The P-type internal reflection focusing layer is composed of AlAs / (Al x3 Ga 1-x3 ) 0.5 In 0.5 The periodic structure of alternating growth of P material, where the value of x3 ranges from 0.7 to 0.8; The high-voltage response layer is composed of highly doped (Al) x1 Ga 1-x1 ) 0.5 In 0.5 P-materials, lightly doped Al 0.5 In 0.5 P-materials, highly doped (Al) x2 Ga 1-x2 ) 0.5 In 0.5 The structure is composed of three segments of material P, where the values ​​of x1 and x2 are both in the range of 0.3 to 0.

6.

2. The infrared LED epitaxial wafer for a remote control according to claim 1, characterized in that, In each periodic structure, the AlAs thickness is 25nm–30nm, and Cp₂Mg is used as the p-type dopant with a doping concentration of 2×10⁻⁶. 18 cm -3 ~3×10 18 cm -3 The (Al) x3 Ga 1-x3 ) 0.5 In 0.5 The thickness of P is 40nm–50nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 1×10⁻⁶. 18 cm -3 ~2×10 18 cm -3 .

3. The infrared LED epitaxial wafer for a remote control according to claim 1, characterized in that, The periodic structure has 6 to 10 cycles.

4. The infrared LED epitaxial wafer for a remote control according to claim 1, characterized in that, The highly doped (Al) x1 Ga 1-x1 ) 0.5 In 0.5 The thickness of the P-material is 100 nm to 200 nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 .

5. The infrared LED epitaxial wafer for a remote control according to claim 1, characterized in that, The low-doped Al 0.5 In 0.5 The thickness of the P-type material is 50 nm to 100 nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 0.5 × 10⁻⁶. 18 cm -3 ~1×10 18 cm -3 .

6. The infrared LED epitaxial wafer for a remote control according to claim 1, characterized in that, The highly doped (Al) x2 Ga 1-x2 ) 0.5 In 0.5 The thickness of the P-material is 100 nm to 200 nm, and Cp₂Mg is used as the P-type dopant with a doping concentration of 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 .

7. A method for preparing an infrared LED epitaxial wafer for a remote control according to any one of claims 1 to 6, characterized in that, Using an MOCVD device, an N-type GaAs buffer layer, an N-type current spreading layer, an N-type confinement layer, a multi-quantum-well light-emitting layer, a P-type confinement layer, a P-type internal reflection focusing layer, a P-type current spreading layer, a high-voltage response layer, and a P-type contact layer are grown sequentially from bottom to top on a GaAs substrate.

8. The method for preparing an infrared LED epitaxial wafer for a remote control according to claim 7, characterized in that, The growth steps of the P-type internal reflection concentrator layer are as follows: The reaction chamber temperature is set to 680℃±10℃; TMAl and AsH3 source materials are introduced into the P-type confinement layer, and Cp2Mg is introduced simultaneously as a dopant to grow AlAs material with a thickness of 25nm~30nm. The flow rate of Cp2Mg is set to 30sccm~60sccm, and the doping concentration is 2×10⁻⁶. 18 cm -3 ~3×10 18 cm -3 Then, turn off AsH3 and introduce TMGa, TMIn, and PH3 to grow Al₂O₃ with a thickness of 40nm–50nm. x3 Ga 1-x3 ) 0.5 In 0.5 For the P material, the set flow rate of Cp2Mg is 50 sccm to 100 sccm, and the doping concentration is 1 × 10⁻⁶. 18 cm -3 ~2×10 18 cm -3 The above-mentioned doped AlAs and (Al x3 Ga 1-x3 ) 0.5 In 0.5 The P-grown combination forms the first pair of internal reflection focusing layers, and then the cycle repeats for 5 to 9 pairs of combined structures.

9. The method for preparing an infrared LED epitaxial wafer for a remote control according to claim 7, characterized in that, The growth steps of the high-voltage response layer are as follows: The reaction chamber temperature is set to 680℃±10℃; TMAl, TMGa, TMIn, and PH3 are introduced onto the P-type current extension layer; and a layer with a thickness of 100nm~200nm (Al) is grown. x1 Ga 1-x1 ) 0.5 In 0.5 P-type material was used, with Cp₂Mg as the P-type dopant. The set flux of Cp₂Mg was 150 sccm to 200 sccm, and the doping concentration was 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 Then, TMGa was turned off, and Al with a thickness of 50 nm to 100 nm was grown. 0.5 In 0.5 For the P material, the set flow rate of Cp2Mg is 20 sccm to 50 sccm, and the doping concentration is 0.5 × 10⁻⁶. 18 cm -3 ~1×10 18 cm -3 Then continue to introduce TMGa to grow Al1 with a thickness of 100nm to 200nm. x2 Ga 1-x2 ) 0.5 In 0.5 For the P material, the set flow rate of Cp2Mg is 150 sccm to 200 sccm, and the doping concentration is 1.5 × 10⁻⁶. 18 cm -3 ~2.5×10 18 cm -3 .

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