Infrared LED epitaxial wafer for remote controller and preparation method thereof

Abstract

The invention relates to the technical field of LEDs, in particular to an infrared LED epitaxial wafer for a remote controller and a preparation method of the infrared LED epitaxial wafer. The infrared LED epitaxial wafer sequentially comprises 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 internal reflection condensation layer, a P-type current expansion layer, a high-voltage response layer and a P-type contact layer from bottom to top. The design of the P-type internal reflection condensation layer and the high-voltage response layer is adopted in a conventional infrared LED epitaxial structure, 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 increased.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and in particular to an infrared LED epitaxial wafer for a remote controller and a preparation method thereof. Background Art

[0002] LEDs (light-emitting diodes), a new generation of lighting sources, offer high luminous intensity, low operating voltage, compact size, long life, and easy packaging. These advantages make LEDs energy-efficient, environmentally friendly, and long-lasting. Infrared LEDs, which emit non-visible light, are widely used in remote control, security monitoring, wearable devices, space communications, medical equipment, sensors, and other fields due to their specific wavelengths, low power consumption, and high reliability.

[0003] With the development and popularization of high-end home appliances, higher requirements are put forward for the response characteristics, optical power index, sensitivity and life of home appliance remote controls. Figure 1 As shown, epitaxial layers are grown starting from a GaAs substrate 100, which are, from bottom to top, an N-type GaAs buffer layer 101, an N-type current spreading layer 102, an N-type confinement layer 103, a multi-quantum well light-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, it is unable to generate a high response current due to the stable series resistance of the epitaxial material itself, which indirectly leads to low current density and low luminous power, and thus an inability to achieve a high radiation intensity. In addition, since the surface contact layer of a conventional infrared LED is GaAs, there is a difference in refractive index between it and the air, resulting in a large dispersion of light emission angles and poor focusing characteristics, resulting in a weak normal zero-degree light intensity, which shortens the distance that the remote control can receive and control, and cannot meet the application scenarios of more products. Due to the above-mentioned shortcomings of conventional infrared LEDs, such as the dispersion and non-concentration of light emission angles, low response current, and low radiation intensity, they often fail to meet the application requirements of high-end home appliance remote controls. Therefore, improving the luminous angle, response current and radiation intensity of infrared LEDs driven by a constant voltage power supply is very urgent for the high-end remote control market. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides an infrared LED epitaxial wafer for a remote control and a preparation method thereof. The infrared LED epitaxial wafer for a remote control can effectively solve the problems of discrete light output angles, poor 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 broadening the product application field.

[0005] The first object of the present invention is to provide an infrared LED epitaxial wafer for a remote control, wherein 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 made of AlAs / (Al x3 Ga 1-x3 ) 0.5 In 0.5 The periodic structure of alternating growth of P materials, where the value of x3 ranges from 0.7 to 0.8; The high voltage response layer is made of highly doped (Al x1 Ga 1-x1 ) 0.5 In 0.5 P material, low-doped Al 0.5 In 0.5 P material, high doping (Al x2 Ga 1-x2 ) 0.5 In 0.5 The structure is composed of three sections of P material, where the values ​​of x1 and x2 are both in the range of 0.3 to 0.6.

[0006] The present invention introduces a functional epitaxial structure cyclically grown with materials having high and low refractive index differences between the P-type confinement layer and the P-type expansion layer, so that photons output from the light-emitting layer can be internally reflected at the heterojunction interface with the high and low refractive index differences, thereby suppressing the escape of light sources at large angles, thereby concentrating most of the light at zero degrees perpendicular to the normal of the chip, and improving the radiation intensity of the infrared LED used as a remote control; the structural design of the high-voltage response layer is introduced between the P-type current expansion layer and the P-type contact layer, and the characteristics of the AlGaInP quaternary material that lattice matches the GaAs material of the infrared LED while modulating the high-potential barrier epitaxial layer as the diffusion current collection area are utilized to improve the response output current of the infrared LED when driven by a constant-voltage power supply, generate more carriers, and improve the problems of insufficient current density and low overall radiation intensity of conventional infrared LEDs when working with a constant-voltage power supply.

[0007] Furthermore, the thickness of AlAs in each periodic structure is 25nm to 30nm, and Cp2Mg is used as a P-type dopant with a doping concentration of 2×10 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 P-type dopant with a doping concentration of 1×10 18 cm -3 ~2×10 18 cm -3 The principle of designing the P-type internal reflection focusing layer in this technical solution is to use AlAs and (Al x3 Ga 1-x3 ) 0.5 In 0.5 The refractive index of the P material is poor, and the abrupt junction barrier effect of the heterojunction interface of arsenide and phosphide makes the light emitted by the infrared LED pass through AlAs and (Al x3 Ga 1-x3 ) 0.5 In 0.5 Internal reflection occurs at the P interface, meaning that wide-angle light cannot refract through the epitaxial layer to the outside air. Instead, it undergoes multiple internal reflections within the epitaxial structure and is focused in a direction perpendicular to the LED chip, thereby enhancing the normal radiation intensity. Furthermore, the abrupt junction barrier created in each cycle facilitates the lateral expansion of high current densities during constant-voltage power supply drive, preventing issues such as increased junction temperature and aging failure of the infrared LED, thereby improving LED reliability.

[0008] Furthermore, the number of cyclic pairs of the periodic structure is 6 to 10 pairs.

[0009] Furthermore, the highly doped (Al x1 Ga 1-x1 ) 0.5 In 0.5 The thickness of the P material is 100nm~200nm, and Cp2Mg is used as the P-type dopant with a doping concentration of 1.5×10 18 cm -3 ~2.5×10 18 cm -3 .

[0010] Furthermore, the low-doped Al 0.5 In 0.5 The thickness of the P material is 50nm to 100nm, and Cp2Mg is used as the P-type dopant with a doping concentration of 0.5×10 18 cm -3 ~1×10 18 cm -3 .

[0011] Furthermore, the highly doped (Al x2 Ga 1-x2 ) 0.5 In 0.5The thickness of the P material is 100nm~200nm, and Cp2Mg is used as the P-type dopant with a doping concentration of 1.5×10 18 cm -3 ~2.5×10 18 cm -3 .

[0012] The principle of designing the high voltage response layer in this technical solution is: when driven by a constant voltage power supply, the introduced high voltage response layer can build a dam-like step-type Schottky barrier between the conventional current expansion layer and the contact layer, helping the current to converge in this area and having a voltage divider effect. x1 Ga 1-x1 ) 0.5 In 0.5 P and (Al x2 Ga 1-x2 ) 0.5 In 0.5 The electron mobility of P is higher than that of Al 0.5 In 0.5 The characteristics of P material ensure that a large amount of current flows in Al when the constant voltage power supply is driven 0.5 In 0.5 The P layer then undergoes radiative recombination through the current spreading layer to the light-emitting layer. Therefore, the high-voltage response layer of the present invention can significantly increase the response current of the infrared LED when driven by a constant-voltage power supply, ensuring that a large number of electrons and holes are generated to participate in radiative recombination, thereby increasing the overall radiation intensity of the device.

[0013] A second object of the present invention is to provide a method for preparing an infrared LED epitaxial wafer for a remote control, using MOCVD (metal organic chemical vapor deposition) equipment to sequentially 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.

[0014] Furthermore, the growth step of the P-type internal reflection focusing layer is as follows: setting the reaction chamber temperature to 680°C ± 10°C, introducing TMAl and AsH3 source materials on the P-type confinement layer, and simultaneously introducing Cp2Mg as a dopant to grow AlAs material with a thickness of 25nm to 30nm, wherein the set flow rate of Cp2Mg is 30sccm to 60sccm, and the doping concentration is 2×10 18 cm -3 ~3×10 18 cm -3 Then turn off AsH3, introduce TMGa, TMIn, and PH3, and grow (Al x3 Ga 1-x3 )0.5 In 0.5 The set flow rate of P material and Cp2Mg is 50 sccm~100 sccm, and the doping concentration is 1×10 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 growth combination forms the first pair of internal reflection focusing layers, and then repeats cycles 5 to 9 to form the combined structure.

[0015] Furthermore, TMAl, TMGa, TMIn, and PH3 are introduced into the P-type current spreading layer to grow a 100nm to 200nm thick (Al x1 Ga 1-x1 ) 0.5 In 0.5 P material, and Cp2Mg is used as the P-type dopant. The set flow rate of Cp2Mg is 150sccm~200sccm, and the doping concentration is 1.5×10 18 cm -3 ~2.5×10 18 cm -3 ; Then turn off TMGa and grow Al with a thickness of 50nm to 100nm 0.5 In 0.5 The set flow rate of P material and Cp2Mg is 20 sccm~50 sccm, and the doping concentration is 0.5×10 18 cm -3 ~1×10 18 cm -3 ; Then continue to introduce TMGa to grow (Al x2 Ga 1-x2 ) 0.5 In 0.5 The set flow rate of P material and Cp2Mg is 150 sccm~200 sccm, and the doping concentration is 1.5×10 18 cm -3 ~2.5×10 18 cm -3 .

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts the design of a P-type internal reflection focusing layer and a high-voltage response layer in a conventional infrared LED epitaxial structure. On the one hand, the design of the P-type internal reflection focusing layer structure allows the photons output from the light-emitting layer to be internally reflected at the heterojunction interface with a high and low refractive index difference, thereby suppressing the escape of the light source at a large angle, thereby focusing most of the light at zero degrees perpendicular to the normal of the chip, thereby improving the radiation intensity of the infrared LED used as a remote control, and at the same time being conducive to the lateral expansion of high current density in constant-voltage power supply drive, reducing chip heat generation and improving the reliability of the infrared LED; on the other hand, the design of the high-voltage response layer can greatly increase the response current of the infrared LED under constant-voltage power supply drive, ensuring the generation of a large number of electrons and holes to participate in radiation recombination, thereby improving the overall radiation intensity of the device; the combination of the two effectively solves the problems of discrete light output angles, poor focusing characteristics, low radiation intensity, etc. of conventional infrared LEDs, and improves the control distance of the remote control. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of a conventional infrared LED epitaxial wafer; Figure 2 This is a schematic structural diagram of an infrared LED epitaxial wafer for a remote controller of the present invention; Figure 3 This is a light intensity spatial distribution curve diagram of the infrared LED used in the remote control of the present invention; Figure 4 This is a graph showing the spatial distribution of light intensity of a conventional infrared LED.

[0018] Description of the numbers in the schematic diagram: 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 DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0020] In the description of this application, it should be understood that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0021] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0022] See also Figures 1 to 4 It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the shape, quantity and proportion of each component can be changed at will, and the component layout may also be more complicated.

[0023] In one embodiment of the present invention, an infrared LED epitaxial wafer for a remote controller is provided, and its structural diagram is shown as follows: Figure 2 As shown, in accordance with the epitaxial growth sequence, from bottom to top 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.

[0024] In some specific embodiments, the P-type internal reflection focusing layer is made of AlAs / (Al x3 Ga 1-x3 ) 0.5 In 0.5 The P material is grown alternately in a periodic structure. The thickness of AlAs in each periodic structure is 25nm to 30nm. Cp2Mg is used as a P-type dopant with a doping concentration of 2×10 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 P-type dopant with a doping concentration of 1×10 18 cm -3 ~2×10 18 cm -3 , the value range of x3 is 0.7~0.8; the number of alternating growth cycles is 6 pairs~10 pairs. The P-type internal reflection focusing layer introduced in the present invention is made of AlAs and (Al x3 Ga 1-x3 ) 0.5 In 0.5 The refractive index of the P material is poor, and the abrupt junction barrier effect of the heterojunction interface of arsenide and phosphide makes the light emitted by the infrared LED pass through AlAs and (Al x3 Ga 1-x3 ) 0.5 In 0.5 Internal reflection is formed at the interface of P, thereby achieving the purpose of enhancing the normal radiation intensity.

[0025] In some specific embodiments, the high voltage response layer is made of highly doped (Al x1 Ga 1-x1 ) 0.5 In 0.5 P material, low-doped Al 0.5 In 0.5 P material, high doping (Al x2 Ga 1-x2 ) 0.5 In 0.5 The epitaxial structure is formed by a combination of P materials, where the values ​​of x1 and x2 are both in the range of 0.3 to 0.6.

[0026] In some embodiments, the highly doped (Al x1 Ga 1-x1 ) 0.5 In 0.5 P is a highly doped layer that grows preferentially near the P-type current spreading layer. The thickness is 100nm to 200nm. This layer uses Cp2Mg as the P-type dopant with a doping concentration of 1.5×10 18 cm -3 ~2.5×10 18 cm -3 .

[0027] In some 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 is then grown, and low-doped Al 0.5 In 0.5The thickness of the P material is 50nm to 100nm. This layer uses Cp2Mg as a P-type dopant with a doping concentration of 0.5×10 18 cm -3 ~1×10 18 cm -3 .

[0028] In some embodiments, the highly doped (Al x2 Ga 1-x2 ) 0.5 In 0.5 P is grown last with a thickness of 100nm to 200nm. This layer uses Cp2Mg as a P-type dopant with a doping concentration of 1.5×10 18 cm -3 ~2.5×10 18 cm -3 The present invention introduces a high-voltage response layer structure design, which takes advantage of the characteristics of the AlGaInP quaternary material that is lattice-matched with the GaAs material of the infrared LED while modulating the high-barrier epitaxial layer as the diffusion current collector area. This improves the response output current of the infrared LED when driven by a constant-voltage power supply, generates more carriers, and improves the problems of insufficient current density and low overall radiation intensity of conventional infrared LEDs when working with a constant-voltage power supply.

[0029] In another embodiment, the present invention also provides a method for preparing an infrared LED epitaxial wafer for a remote control, using MOCVD equipment to sequentially grow 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 from bottom to top. Specifically, the method includes the following steps: (1) The MOCVD was evacuated to 50 mbar in a pure H2 atmosphere, and the reaction chamber temperature was set to 400°C. The GaAs substrate was then transferred to the reaction chamber through a robot transfer bin, and then the temperature was rapidly raised to 730°C and maintained at 730°C for 5 minutes.

[0030] (2) Growth of N-type GaAs buffer layer: The reaction chamber temperature was set to 680℃±10℃, TMGa and AsH3 were introduced, and a GaAs buffer layer material with a thickness of 100nm to 300nm was grown. SiH4 was used as the N-type dopant with a doping concentration of 3×10 18 cm -3 ~5×10 18 cm -3 .

[0031] (3) Growth of N-type current spreading layer: Set the reaction chamber temperature to 680℃±10℃, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 3000nm~4000nm. y1 Ga 1-y1 As material, the value range of y1 is 0.1~0.2, SiH4 is used as N-type dopant, and the doping concentration is 0.7×10 18 cm -3 ~1.5×10 18 cm -3 .

[0032] (4) Growth of N-type confinement layer: Set the reaction chamber temperature to 680℃±10℃, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 400nm~500nm. y2 Ga 1-y2 As material, where the value of y2 ranges from 0.25 to 0.60, SiH4 is used as the N-type dopant with a doping concentration of 2×10 18 cm -3 ~3×10 18 cm -3 .

[0033] (5) Growth of multi-quantum well light-emitting layer: Set the temperature of the reaction chamber to 660℃±10℃, introduce TMAl, TMGa, TMIn, AsH3, and PH3, and the growth wells and barriers are In y3 Ga 1-y3 As、(Al y4 Ga 1-y4 ) 0.5 As 0.5 The periodic cyclic structure of P material. y3 Ga 1-y3 The thickness of As is 7nm to 9nm, the value range of y3 is 0.15 to 0.18, and the single-layer quantum barrier (Al y4 Ga 1-y4 ) 0.5 As 0.5 The thickness of P is 24 nm to 30 nm, the value of y4 ranges from 0.15 to 0.25, the number of periodic cycle pairs is 8 to 12 pairs, and both the wells and barriers are undoped.

[0034] (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 As material, where the value of y5 ranges from 0.25 to 0.60, CCl4 is used as the P-type dopant with a doping concentration of 2×1018 cm -3 ~3×10 18 cm -3 .

[0035] (7) Growth of P-type internal reflection focusing layer: The reaction chamber temperature was set to 680℃±10℃, TMAl and AsH3 source materials were introduced into the P-type confinement layer, and Cp2Mg was introduced as a dopant to grow AlAs material with a thickness of 25nm~30nm. The set flow rate of Cp2Mg was 30sccm~60sccm, and the doping concentration was 2×10 18 cm -3 ~3×10 18 cm -3 Then turn off AsH3, introduce TMGa, TMIn, and PH3, and grow (Al x3 Ga 1-x3 ) 0.5 In 0.5 The set flow rate of P material and Cp2Mg is 50 sccm~100 sccm, and the doping concentration is 1×10 18 cm -3 ~2×10 18 cm -3 , x3 ranges from 0.7 to 0.8. x3 Ga 1-x3 ) 0.5 In 0.5 The P growth combination forms the first pair of internal reflection focusing layers, and then the cycle is repeated for 5 to 9 pairs of combination structures.

[0036] (8) Growth of P-type current spreading layer: Set the reaction chamber temperature to 680℃±10℃, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 6000nm~8000nm. y6 Ga 1-y6 As material, the value range of y6 is 0.1~0.2, CCl4 is used as P-type dopant, and the doping concentration is 0.5×10 18 cm -3 ~2×10 18 cm -3 .

[0037] (9) Growth of high voltage response layer: Set the temperature of the reaction chamber to 680℃±10℃, introduce TMAl, TMGa, TMIn, and PH3 into the P-type current spreading layer, and grow (Al) with a thickness of 100nm to 200nm. x1 Ga 1-x1 ) 0.5 In 0.5P material, using Cp2Mg as the P-type dopant, the set flow rate of Cp2Mg is 150sccm~200sccm, the value range of x1 is 0.3~0.6, and the doping concentration is 1.5×10 18 cm -3 ~2.5×10 18 cm -3 ; Then turn off TMGa and grow Al with a thickness of 50nm to 100nm 0.5 In 0.5 The set flow rate of P material and Cp2Mg is 20 sccm~50 sccm, and the doping concentration is 0.5×10 18 cm -3 ~1×10 18 cm -3 ; Then continue to introduce TMGa to grow (Al 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 range of x2 is 0.3 to 0.6, and the doping concentration is 1.5×10 18 cm -3 ~2.5×10 18 cm -3 .

[0038] (10) Growth of P-type contact layer: The reaction chamber temperature was set to 650℃±10℃, TMGa and AsH3 were introduced, and GaAs contact layer material with a thickness of 60nm~100nm was grown. CCl4 was used as the P-type dopant with a doping concentration of 0.5×10 20 cm -3 ~2×10 20 cm -3 .

[0039] (11) Wafer removal: After the growth is completed, the temperature of the MOCVD reaction chamber is lowered to 110°C, and then the pressure is adjusted to 1000 mbar. The reaction chamber is opened and the epitaxial wafer is removed.

[0040] In order to further illustrate the present invention, the present invention is described in detail below with reference to specific embodiments.

[0041] Example 1 A method for preparing an epitaxial wafer of an infrared LED for a remote control, comprising the following steps: (1) The MOCVD was evacuated to 50 mbar in a pure H2 atmosphere, and the reaction chamber temperature was set to 400°C. The GaAs substrate was then transferred to the reaction chamber through a robot transfer bin, and then the temperature was rapidly raised to 730°C and maintained at 730°C for 5 minutes.

[0042] (2) Growth of N-type GaAs buffer layer: The reaction chamber temperature was set to 680°C, TMGa and AsH3 were introduced, and a GaAs buffer layer material with a thickness of 300 nm was grown. SiH4 was used as the N-type dopant with a doping concentration of 5×10 18 cm -3 .

[0043] (3) Growth of N-type current spreading layer: Set the reaction chamber temperature to 680℃, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 4000nm. 0.1 Ga 0.9 As material, SiH4 is used as N-type dopant, and the doping concentration is 1.5×10 18 cm -3 .

[0044] (4) Growth of N-type confinement layer: Set the reaction chamber temperature to 680℃, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 500nm. 0.3 Ga 0.7 As material, SiH4 is used as N-type dopant with a doping concentration of 2×10 18 cm -3 .

[0045] (5) Growth of multi-quantum well light-emitting layer: Set the temperature of the reaction chamber to 660℃, introduce TMAl, TMGa, TMIn, AsH3, and PH3, and the growth wells and barriers are In 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 the single-layer quantum well In 0.17 Ga 0.83 The thickness of As is 9nm, and the 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 periodic cycles is 10 pairs, and both the wells and barriers are non-doped.

[0046] (6) Growth of P-type confinement layer: Set the reaction chamber temperature to 680°C, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 500nm. 0.3 Ga0.7 As material, CCl4 is used as P-type dopant with a doping concentration of 2×10 18 cm -3 .

[0047] (7) Growth of P-type internal reflection focusing layer: The reaction chamber temperature was set to 680 °C, TMAl and AsH3 source materials were introduced into the P-type confinement layer, and Cp2Mg was introduced as a dopant to grow AlAs material with a thickness of 30 nm. The set flow rate of Cp2Mg was 50 sccm, and the doping concentration was 2×10 18 cm -3 Then turn off AsH3, introduce TMGa, TMIn, and PH3, and grow (Al 0.72 Ga 0.28 ) 0.5 In 0.5 The set flow rate of P material, Cp2Mg is 70 sccm, and the doping concentration is 1.3×10 18 cm -3 , the above co-doped AlAs and (Al 0.72 Ga 0.28 ) 0.5 In 0.5 The P growth combination forms the first pair of internal reflection concentrating layers, and then the cycle 8 is repeated for the combined structure.

[0048] (8) Growth of P-type current spreading layer: Set the reaction chamber temperature to 680℃, introduce TMGa, TMAl, and AsH3, and grow Al with a thickness of 7600nm. 0.18 Ga 0.82 As material, CCl4 is used as P-type dopant with a doping concentration of 1.8×10 18 cm -3 .

[0049] (9) Growth of high voltage response layer: Set the temperature of the reaction chamber to 680℃, introduce TMAl, TMGa, TMIn, and PH3 into the P-type current spreading layer, and grow (Al 0.35 Ga 0.65 ) 0.5 In 0.5 P material, this layer uses Cp2Mg as a P-type dopant, the set flow rate of Cp2Mg is 170sccm, and the doping concentration is 2.1×10 18 cm -3 ; Then turn off TMGa and grow Al with a thickness of 80nm 0.5 In 0.5 The set flow rate of P material, Cp2Mg is 40 sccm, and the doping concentration is 0.85×10 18 cm-3 ; Then continue to introduce TMGa to grow a 150nm thick (Al 0.4 Ga 0.6 ) 0.5 In 0.5 The set flow rate of P material, Cp2Mg is 180 sccm, and the doping concentration is 2.3×10 18 cm -3 .

[0050] (10) Growth of P-type contact layer: The reaction chamber temperature was set to 650°C, TMGa and AsH3 were introduced, and a GaAs contact layer material with a thickness of 80 nm was grown. CCl4 was used as the P-type dopant with a doping concentration of 1.2×10 20 cm -3 .

[0051] (11) Wafer removal: After the growth is completed, the temperature of the MOCVD reaction chamber is lowered to 110°C, and then the pressure is adjusted to 1000 mbar. The reaction chamber is opened and the epitaxial wafer is removed.

[0052] Comparative Example 1 A conventional infrared LED epitaxial wafer is prepared using conventional methods, and its structural diagram is shown in FIG. Figure 1 shown.

[0053] Test example The infrared LED obtained in Example 1 and the infrared LED obtained in Comparative Example 1 were tested under constant voltage power supply, and the radiation intensity and different light intensity diffusion angles were compared. The results are shown in Table 1. At the same time, the light intensity space test curve distribution diagrams are shown in Table 1. Figure 3 and Figure 4 shown.

[0054] Table 1 Comparison of radiation intensity and diffusion angles of different light intensities

[0055] From the test results, it can be seen that the light intensity diffusion angles of the infrared LED used in the remote control prepared by the present invention are significantly smaller than those of conventional infrared LEDs. When the light intensity diffusion is 10%, the light intensity angle of Example 1 is 50.18°, and the light intensity angle of Comparative Example 1 is 66.43°. Compared with Example 1, the light intensity angle of Example 1 is reduced by 24%, and the light concentration is better concentrated at the normal zero-degree angle. It can also be clearly seen from the light intensity spatial test distribution diagram that the light intensity distribution of the infrared LED of the present invention is more concentrated, which significantly improves the discreteness of the light source. In addition, from the zero-degree radiation intensity test, the radiation intensity of the infrared LED of Example 1 of the present invention is 25.89mW / sr, which is 41.9% higher than the 18.24mW / sr of the infrared LED of Comparative Example 1, further illustrating that the technical solution of the present invention has a significant improvement effect on the improvement of radiation intensity.

[0056] Finally, it should be emphasized that the above 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 may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An infrared LED epitaxial wafer for a remote control, characterized in that: The infrared LED epitaxial wafer includes, 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 made of AlAs / (Al x3 Ga 1-x3 ) 0.5 In 0.5 The periodic structure of alternating growth of P materials, where the value of x3 ranges from 0.7 to 0.8; The high voltage response layer is made of highly doped (Al x1 Ga 1-x1 ) 0.5 In 0.5 P material, low-doped Al 0.5 In 0.5 P material, high doping (Al x2 Ga 1-x2 ) 0.5 In 0.5 The structure is composed of three sections of P material, 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 remote control according to claim 1, characterized in that: In each periodic structure, the thickness of AlAs is 25nm to 30nm, and Cp2Mg is used as a P-type dopant with a doping concentration of 2×10 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 P-type dopant with a doping concentration of 1×10 18 cm -3 ~2×10 18 cm -3 .

3. The infrared LED epitaxial wafer for remote control according to claim 1, characterized in that: The number of cyclic pairs of the periodic structure is 6 to 10 pairs.

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

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

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

7. The method for preparing an infrared LED epitaxial wafer for a remote controller according to any one of claims 1 to 6, characterized in that: Using MOCVD equipment, 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 on a GaAs substrate from bottom to top.

8. The method for preparing an infrared LED epitaxial wafer for a remote controller according to claim 7, wherein: The growth steps of the P-type internal reflection focusing layer are as follows: setting the reaction chamber temperature to 680°C ± 10°C, introducing TMAl and AsH3 source materials on the P-type confinement layer, and simultaneously introducing Cp2Mg as a dopant to grow AlAs material with a thickness of 25nm to 30nm, wherein the set flow rate of Cp2Mg is 30sccm to 60sccm, and the doping concentration is 2×10 18 cm -3 ~3×10 18 cm -3 Then turn off AsH3, introduce TMGa, TMIn, and PH3, and grow (Al x3 Ga 1-x3 ) 0.5 In 0.5 The set flow rate of P material and Cp2Mg is 50 sccm~100 sccm, and the doping concentration is 1×10 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 growth combination forms the first pair of internal reflection focusing layers, and then repeats cycles 5 to 9 to form the combined structure.

9. The method for preparing an infrared LED epitaxial wafer for a remote controller according to claim 7, wherein: The growth steps of the high voltage response layer are as follows: setting the reaction chamber temperature to 680°C ± 10°C, introducing TMAl, TMGa, TMIn, and PH3 into the P-type current spreading layer, and growing (Al) with a thickness of 100nm to 200nm. x1 Ga 1-x1 ) 0.5 In 0.5 P material, and Cp2Mg is used as the P-type dopant. The set flow rate of Cp2Mg is 150sccm~200sccm, and the doping concentration is 1.5×10 18 cm -3 ~2.5×10 18 cm -3 ; Then turn off TMGa and grow Al with a thickness of 50nm to 100nm 0.5 In 0.5 The set flow rate of P material and Cp2Mg is 20 sccm~50 sccm, and the doping concentration is 0.5×10 18 cm -3 ~1×10 18 cm -3 ; Then continue to introduce TMGa to grow (Al x2 Ga 1-x2 ) 0.5 In 0.5 The set flow rate of P material and Cp2Mg is 150 sccm~200 sccm, and the doping concentration is 1.5×10 18 cm -3 ~2.5×10 18 cm -3 .

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