AlGaInP-based epitaxial wafer, preparation method and LED

Abstract

The present invention provides an AlGaInP-based epitaxial wafer, a preparation method and an LED. The epitaxial wafer comprises, from bottom to top, a substrate, an intermediate layer, an N-type semiconductor layer, an active layer and a P-type semiconductor layer. The N-type semiconductor layer comprises a resonant potential well layer arranged close to the active layer. The resonant potential well layer comprises a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer. The potential barrier sublayer is a non-doped AlGaInP sublayer. The potential well sublayer comprises (AlGaInP) sublayers arranged periodically and alternately from bottom to top. x Ga 1‑x ) 0.5 In 0.5 P first sublayer and (Al Y Ga 1‑Y ) 0.5 In 0.5 P second sublayer, the (Al x Ga 1‑x ) 0.5 In 0.5 The bandgap width of the first sublayer of P gradually decreases from bottom to top. Y Ga 1‑Y ) 0.5 In 0.5 The potential barrier of the second sublayer of P is higher than (Al x Ga 1‑x ) 0.5 In 0.5 The potential barrier of the first sublayer of P can cause resonance between the multiple wells, capture more electrons, increase the lateral expansion rate of electrons, reduce the electron movement speed, and reduce the risk of epitaxial wafer breakdown.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to an AlGaInP-based epitaxial wafer, a preparation method and an LED. Background Art

[0002] As a new type of semiconductor solid-state light source, light emitting diode (LED) has set off a new wave in the field of lighting due to its superior performance and is known as the fourth generation of green lighting. With the rapid development of display technology, MicroLED display technology has gradually taken the lead. Compared with competing technologies based on LCD, LED, MiniLED and organic LED, MicroLED has more advantages, such as: excellent brightness, high contrast, unparalleled efficiency, longer service life and higher stability. More importantly, based on the micron scale, they can match human visual receptors and provide truly realistic images. Due to the small chip size, low current density, high uniformity requirements, low luminous efficiency at small current density, complex chip manufacturing process, and low mass transfer yield, MicroLED's development of full-color display is restricted.

[0003] As a type of MicroLED, the quaternary AlGaInP-LED has a general epitaxial growth direction structure including: substrate, buffer layer, Bragg reflection layer, N-AlInP confinement layer, waveguide layer-active quantum well structure, P-AlGaInP waveguide layer, P-AlInP confinement layer, P-GaP current spreading layer, and GaP ohmic contact layer.

[0004] In the existing technology, the internal quantum efficiency of the quaternary AlGaInP LED decreases with the decrease of wavelength. The main reason is that the quaternary Al value increases in the active region with shorter wavelengths, and the quantum efficiency of the quantum well material is low near the gap energy band. The quaternary AlGaInP LED band is generally 570-575nm, close to the gap energy band, so the decrease in internal quantum efficiency becomes a bottleneck for the brightness of the quaternary AlGaInP LED. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an AlGaInP-based epitaxial wafer, aiming to solve the problem in the prior art that the internal quantum efficiency of the quaternary AlGaInP LED decreases with shorter wavelengths. The main reason is that the quaternary Al value increases in the active region with shorter wavelengths, the quantum well material is close to the gap energy band, the internal quantum efficiency is low, and the luminous intensity cannot be improved.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] An AlGaInP-based epitaxial wafer, comprising, from bottom to top, a substrate, an intermediate layer, an N-type semiconductor layer, an active layer and a P-type semiconductor layer, wherein the N-type semiconductor layer comprises a resonant potential well layer arranged close to the active layer, the resonant potential well layer comprises a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer, the potential barrier sublayer is a non-doped AlGaInP sublayer, and the potential well sublayer comprises (AlGaInP) sublayers arranged periodically and alternately from bottom to top. x Ga 1-x ) 0.5 In 0.5 P first sublayer and (Al Y Ga 1-Y ) 0.5 In 0.5 P second sublayer, the (Al x Ga 1-x ) 0.5 In 0.5 The bandgap width of the first sublayer of P gradually decreases from bottom to top. Y Ga 1-Y ) 0.5 In 0.5 The potential barrier of the second sublayer of P is higher than (Al x Ga 1-x ) 0.5 In 0.5 P potential barrier of the first sublayer.

[0008] According to one aspect of the above technical solution, the (Al x Ga 1-x ) 0.5 In 0.5 P first sublayer and the (Al Y Ga 1-Y ) 0.5 In 0.5 The stacking period of the second sublayer of P is 2~8.

[0009] According to one aspect of the above technical solution, in the (Al x Ga 1-x ) 0.5 In 0.5 In the first sublayer, 0≤x≤0.7, in the (Al Y Ga 1-Y ) 0.5 In 0.5 In the second sublayer, 0.7 <Y<1。

[0010] According to one aspect of the above technical solution, the growth thickness of the barrier sublayer is 10Å~100Å, and the wide well thickness of the potential well sublayer is ≥200Å.

[0011] According to one aspect of the above technical solution, the intermediate layer includes a buffer layer and a Bragg reflection layer arranged in sequence from bottom to top.

[0012] According to one aspect of the above technical solution, the N-type semiconductor layer also includes an N-AlInP confinement layer and an N-AlGaInP waveguide layer arranged in sequence from bottom to top, and the resonant potential well layer is located between the N-AlGaInP waveguide layer and the active layer.

[0013] According to one aspect of the above technical solution, the P-type semiconductor layer includes a P-AlGaInP waveguide layer, a P-AlInP confinement layer, a P-GaP window layer and a P-GaP ohmic contact layer arranged in sequence from bottom to top.

[0014] The present invention also provides a method for preparing an AlGaInP-based epitaxial wafer, comprising the following steps:

[0015] providing a substrate;

[0016] Depositing an intermediate layer and an N-type semiconductor layer in sequence on the substrate;

[0017] The N-type semiconductor layer includes a resonant potential well layer, the resonant potential well layer includes a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer, the potential barrier sublayer is a non-doped AlGaInP sublayer, and the potential well sublayer includes (AlGaInP) arranged periodically and alternately from bottom to top. x Ga 1-x ) 0.5 In 0.5 P first sublayer and (Al Y Ga 1-Y ) 0.5 In 0.5 P second sublayer, the (Al x Ga 1-x ) 0.5 In 0.5 The bandgap width of the first sublayer of P gradually decreases from bottom to top. Y Ga 1-Y ) 0.5 In 0.5 The potential barrier of the second sublayer of P is higher than (Al x Ga 1-x ) 0.5 In 0.5 P potential barrier of the first sublayer;

[0018] An active layer and a P-type semiconductor layer are sequentially deposited on the barrier sublayer.

[0019] According to one aspect of the above technical solution, when preparing the resonant potential well layer, the reaction temperature is 600°C~700°C, the growth thickness of the barrier sublayer is 10Å~100Å, and the wide well thickness of the potential well sublayer is ≥200Å.

[0020] The present invention also provides an LED, comprising the AlGaInP-based epitaxial wafer as described above.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] By setting a resonant potential well layer, the specific resonant potential well layer includes a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer, and the potential well sublayer includes (Al x Ga 1-x ) 0.5 In 0.5 P first sublayer and (Al Y Ga 1-Y ) 0.5 In 0.5 The second sublayer of P is made by (Al x Ga 1-x ) 0.5 In 0.5 The bandgap width of the first P sublayer gradually decreases from bottom to top along the growth direction, so that a resonant tunnel is formed between each unbalanced charge. Multiple such resonant tunnels can reduce electron overshoot and stray light; thereby reducing the thickness of the electron barrier layer on the P-type semiconductor side, saving raw materials and growth time costs; at the same time, enhancing the lateral expansion of electrons, increasing the radiation area of ​​the light-emitting area, and increasing the internal quantum rate;

[0023] The present invention is achieved by x Ga 1-x ) 0.5 In 0.5 The first P sublayer is made into a structure with a gradually decreasing bandgap width. This structure with different potential barriers growing alternately can cause resonance between multiple wells, capture more electrons, increase the lateral expansion rate of electrons, and reduce the electron movement speed. It can also allow more radiation recombination with holes in the light-emitting area, reducing the risk of epitaxial wafer breakdown. At the same time, it can reduce the thickness of the P-side electron resistance layer, save raw materials, and growth time costs, thereby solving the problem of lower quantum efficiency of quaternary AlGaInPLED with shorter wavelength. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0025] Figure 1It is a schematic structural diagram of an AlGaInP-based epitaxial wafer in the first embodiment of the present invention;

[0026] Figure 2 It is a schematic diagram of the local structure of the AlGaInP-based epitaxial wafer at the resonant potential well layer in the first embodiment of the present invention;

[0027] Figure 3 Schematic diagram of the process of preparing an AlGaInP-based epitaxial wafer in the second embodiment of the present invention;

[0028] Description of main component symbols:

[0029] 1. Substrate; 2. Buffer layer; 3. Bragg reflection layer; 4. N-AlInP confinement layer; 5. N-AlGaInP waveguide layer; 6. Resonant potential well layer; 7. Active layer; 8. P-AlGaInP waveguide layer; 9. P-AlInP confinement layer; 10. P-GaP window layer; 11. P-GaP ohmic contact layer; 61. AlGaInP sublayer; 63. (Al x Ga 1-x ) 0.5 In 0.5 P first sublayer; 62, (Al Y Ga 1-Y ) 0.5 In 0.5 P second sublayer.

[0030] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0032] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0034] Embodiment 1

[0035] See also Figure 1 to Figure 2 , shown is an AlGaInP-based epitaxial wafer in the first embodiment of the present invention, which includes a substrate 1, an intermediate layer, an N-type semiconductor layer, an active layer 7 and a P-type semiconductor layer from bottom to top, wherein the N-type semiconductor layer includes a resonant potential well layer 6 arranged close to the active layer 7, wherein the resonant potential well layer 6 includes a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer, wherein the potential barrier sublayer is a non-doped AlGaInP sublayer 61, and the potential well sublayer includes (Al x Ga 1-x ) 0.5 In 0.5 P first sublayer 63 and (Al Y Ga 1-Y ) 0.5 In 0.5 The second sublayer 62, the (Al x Ga 1-x ) 0.5 In 0.5 The bandgap width of the first sublayer 63 decreases gradually from bottom to top. Y Ga 1-Y ) 0.5 In 0.5 The potential barrier of the second sublayer 62 is higher than (Al x Ga 1-x ) 0.5 In 0.5 P potential barrier of the first sublayer 63 .

[0036] It is understandable that in the prior art, the internal quantum efficiency of the quaternary AlGaInP LED decreases with the decrease of wavelength. The main reason is that the quaternary Al value increases in the shorter wavelength active region, and the quantum efficiency of the quantum well material is low near the gap energy band. The quaternary AlGaInP LED band is generally 570-575nm, close to the gap energy band, so the decrease in internal quantum efficiency becomes the bottleneck of the brightness of the quaternary AlGaInP LED. Therefore, the present invention sets a resonant potential well layer 6, specifically, the resonant potential well layer 6 includes a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer, and the potential well sublayer includes (Al2O3) arranged periodically and alternately from bottom to top. x Ga1-x ) 0.5 In 0.5 P first sublayer 63 and (Al Y Ga 1-Y ) 0.5 In 0.5 The second sublayer 62 is formed by making (Al x Ga 1-x ) 0.5 In 0.5 The bandgap width of the first P sublayer 63 gradually decreases from bottom to top along the growth direction, so that a resonant tunnel is formed between each unbalanced charge. Multiple such resonant tunnels can reduce electron overshoot and stray light; thereby reducing the thickness of the electron blocking layer on the P-type semiconductor side, saving raw materials and growth time costs; at the same time, enhancing the lateral expansion of electrons, increasing the radiation area of ​​the light-emitting area, and increasing the internal quantum rate;

[0037] The present invention is achieved by x Ga 1-x ) 0.5 In 0.5 The P first sublayer 63 is designed with a gradually decreasing bandgap width, which can cause resonance between multiple wells, capture more electrons, increase the lateral expansion rate of electrons, and reduce the electron movement speed, allowing more radiation recombination with holes in the light-emitting area, reducing the risk of epitaxial wafer breakdown.

[0038] Further, the (Al x Ga 1-x ) 0.5 In 0.5 The first sublayer 63 and the (Al Y Ga 1-Y ) 0.5 In 0.5 The stacking period of the P second sub-layer 62 is 2-8.

[0039] Further, in the (Al x Ga 1-x ) 0.5 In 0.5 In the first sublayer 63, 0≤x≤0.7, in the (Al Y Ga 1-Y ) 0.5 In 0.5 P in the second sublayer 62, 0.7 <Y<1。

[0040] Understandably, (Al x Ga 1-x ) 0.5 In 0.5 The first sublayer 63 of P gradually decreases along the growth direction, so that (Al x Ga1-x ) 0.5 In 0.5 The bandgap of the P first sublayer 63 gradually decreases.

[0041] Furthermore, the growth thickness of the barrier sublayer is 10Å~100Å, and the wide well thickness of the potential well sublayer is ≥200Å.

[0042] Exemplarily, in this embodiment, the intermediate layer includes a buffer layer 2 and a Bragg reflection layer 3 arranged in sequence from bottom to top; the N-type semiconductor layer also includes an N-AlInP confinement layer 4 and an N-AlGaInP waveguide layer 5 arranged in sequence from bottom to top, and the resonant potential well layer 6 is located between the N-AlGaInP waveguide layer 5 and the active layer 7; the P-type semiconductor layer includes a P-AlGaInP waveguide layer 8, a P-AlInP confinement layer 9, a P-GaP window layer 10 and a P-GaP ohmic contact layer 11 arranged in sequence from bottom to top.

[0043] In summary, the AlGaInP-based epitaxial wafer in the above embodiment of the present invention is provided with a resonant potential well layer 6, specifically, the resonant potential well layer 6 includes a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer, and the potential well sublayer includes (Al x Ga 1-x ) 0.5 In 0.5 P first sublayer 63 and (Al Y Ga 1-Y ) 0.5 In 0.5 The second sublayer 62 is formed by making (Al x Ga 1-x ) 0.5 In 0.5 The bandgap width of the first P sublayer 63 gradually decreases from bottom to top along the growth direction, so that a resonant tunnel is formed between each unbalanced charge. Multiple such resonant tunnels can reduce electron overshoot and stray light; thereby reducing the thickness of the electron blocking layer on the P-type semiconductor side, saving raw materials and growth time costs; at the same time, enhancing the lateral expansion of electrons, increasing the radiation area of ​​the light-emitting area, and increasing the internal quantum rate;

[0044] The present invention is achieved by x Ga 1-x ) 0.5 In 0.5The P first sublayer 63 is made to have a gradually decreasing bandgap width. This structure of alternating growth of different potential barriers can cause resonance between multiple wells, capture more electrons, and increase the lateral expansion rate of electrons. At the same time, it reduces the electron movement speed, allowing more radiation recombination with holes in the light-emitting area, reducing the risk of epitaxial wafer breakdown, and at the same time reducing the thickness of the P-side electron resistance layer, saving raw materials and growth time costs; thereby solving the problem of lower quantum efficiency of quaternary AlGaInPLED with shorter wavelength.

[0045] Embodiment 2

[0046] Please refer to Figure 3 , which is a method for preparing an AlGaInP-based epitaxial wafer in a second embodiment of the present invention, comprising the following steps S10 to S30:

[0047] S10, providing a substrate;

[0048] Exemplarily, in this embodiment, the selected substrate is a GaAs substrate, which has a mature preparation process, high stability, and high cost performance;

[0049] S20, depositing an intermediate layer and an N-type semiconductor layer in sequence on the substrate;

[0050] The intermediate layer includes a buffer layer and a Bragg reflection layer arranged in sequence from bottom to top;

[0051] Specifically, a buffer layer is deposited on a GaAs substrate, wherein the buffer layer is a Si-doped GaAs buffer layer. The specific deposition process is to control the temperature of the reaction chamber at 600°C-700°C, use TMGa as a Ga source, AsH3 as an As source, and Si2H6 as a dopant, and grow a GaAs buffer layer with a thickness of 50nm-500nm, wherein the Si doping concentration is 1×10 17 atoms / cm 3 ~1×10 19 atoms / cm 3 In this embodiment, the reaction chamber temperature is 650°C, the growth thickness is 300nm, and the Si doping concentration is 1×10 18 atoms / cm 3 .

[0052] Furthermore, a Bragg reflection layer is deposited on the buffer layer. The Bragg reflection layer is composed of AlGaAs and AlAs grown alternately, with a period number of 3 to 35. The specific deposition process is to control the growth temperature at 680°C to 720°C, the reaction chamber pressure at 40 mbar to 60 mbar, use TMAl as the Al source, TMGa as the Ga source, and AsH3 as the As source, grow a Bragg reflection layer with a thickness of 1.2um to 2um, and the Si doping concentration is 1×10 17 atoms / cm 3 ~1×10 19 atoms / cm 3 In this embodiment, the number of cycles is 20, the growth temperature is 700°C, the reaction chamber pressure is 50 mbar, the thickness of the formed Bragg reflection layer is 1.5 um, and the doping concentration of Si is 1×10 18 atoms / cm 3 .

[0053] The N-type semiconductor layer includes an N-AlInP confinement layer, an N-AlGaInP waveguide layer and a resonant potential well layer arranged in sequence from bottom to top;

[0054] Furthermore, a N-AlInP confinement layer is prepared on the Bragg reflector layer. The specific deposition process is as follows: the reaction chamber temperature is controlled at 700°C to 750°C, the reaction chamber pressure is controlled at 40 mbar to 60 mbar, TMAl is used as an Al source, TMIn is used as an In source, PH3 is used as a P source, and Si2H6 is used as a dopant to grow an N-AlInP confinement layer with a thickness of 250 nm to 450 nm, wherein the Si doping concentration is 1×10 17 atoms / cm 3 ~1×10 19 atoms / cm 3 In this embodiment, the reaction chamber temperature is 720°C, the reaction chamber pressure is 50 mbar, the thickness of the formed N-AlInP confinement layer is 300 nm, and the Si doping concentration is 1×10 18 atoms / cm 3 .

[0055] Furthermore, an N-AlGaInP waveguide layer is prepared on the N-AlInP limiting layer. The specific deposition process is to control the temperature of the reaction chamber at 600°C~700°C, use TMAl as the Al source, TMGa as the Ga source, and AsH3 as the As source to grow an N-AlGaInP waveguide layer with a thickness of 100nm-300nm. In this embodiment, the reaction chamber temperature is 650°C, and the thickness of the formed N-AlGaInP waveguide layer is 200nm.

[0056] Further, a resonant potential well layer is prepared on the N-AlGaInP waveguide layer. The resonant potential well layer includes a potential well sub-layer and barrier sub-layers disposed at both ends of the potential well sub-layer. The barrier sub-layers are undoped AlGaInP sub-layers. The potential well sub-layer includes (Al x Ga 1-x ) 0.5 In 0.5 P first sub-layers and (Al Y Ga 1-Y ) 0.5 In 0.5 P second sub-layers, which are arranged in a periodic and alternating manner from bottom to top. The bandgap of the (Al x Ga 1-x ) 0.5 In 0.5 P first sub-layer gradually decreases from bottom to top. The barrier of the (Al Y Ga 1-Y ) 0.5 In 0.5 P second sub-layer is higher than that of the (Al x Ga 1-x ) 0.5 In 0.5 P first sub-layer.

[0057] The specific deposition process is as follows: The temperature of the reaction chamber is controlled at 600°C to 700°C. TMAl is used as the Al source, TMGa is used as the Ga source, TMIn is used as the In source, and PH3 is used as the P source. An AlGaInP sub-layer with a thickness of 10 Å to 100 Å is prepared on the N-AlGaInP waveguide layer. Subsequently, (Al x Ga 1-x ) 0.5 In 0.5 P first sub-layers and (Al Y Ga 1-Y ) 0.5 In 0.5 P second sub-layers are alternately prepared on the AlGaInP sub-layer, and the number of periods is 2 to 8. In the (Al x Ga 1-x ) 0.5 In 0.5 P first sub-layer, 0 ≤ x ≤ 0.7. In the (Al Y Ga 1-Y ) 0.5 In 0.5 P second sub-layer, 0.7 < Y < 1. The width of the wide well of the potential well sub-layer is ≥ 200 Å. Then, on the (Al Y Ga 1-Y ) 0.5 In 0.5An AlGaInP sublayer with a thickness of 10Å to 100Å is prepared on the second AlGaInP sublayer. It should be noted that, as a preferred embodiment, the element layers close to the two AlGaInP sublayers are (Al x Ga 1-x ) 0.5 In 0.5 P first sublayer. In this embodiment, the reaction chamber temperature is 650°C, and the thickness of the AlGaInP sublayers formed on both sides is 60Å. Y Ga 1-Y ) 0.5 In 0.5 P second sublayer and (Al x Ga 1-x ) 0.5 In 0.5 The alternating period number of the first sublayer of P is 8, Y is 0.9, and the values ​​of x are 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0 from the lowest layer to the highest layer, respectively. The wide well thickness of the potential well sublayer formed is 350 Å.

[0058] It can be understood that this structure forms a resonant tunnel between each unbalanced charge. Multiple such resonant tunnels can reduce electron overshoot and stray light; thereby reducing the thickness of the electron barrier layer on the P-type semiconductor side, saving raw materials and time costs for growth; and at the same time enhancing the lateral expansion of electrons, increasing the radiation area of ​​the light-emitting area, and increasing the internal quantum rate. The present invention is achieved by (Al x Ga 1-x ) 0.5 In 0.5 The first P sublayer is made with a gradually decreasing bandgap width. This structure with different potential barriers growing alternately can cause resonance between multiple wells, capture more electrons, increase the lateral expansion rate of electrons, and reduce the electron movement speed. It can radiate and recombine with holes in the light-emitting area more, reduce the risk of epitaxial wafer breakdown, and reduce the thickness of the P-side electron resistance layer, saving raw materials and growth time costs. This solves the problem of lower quantum efficiency of quaternary AlGaInP LEDs with shorter wavelengths.

[0059] S30, sequentially depositing an active layer and a P-type semiconductor layer on the barrier sublayer;

[0060] Specifically, the active layer is a superlattice multi-quantum structure layer in which an AlGaInP layer and a GaInP layer are alternately grown, wherein the AlGaInP layer is a barrier layer and the GaInP layer is a well layer. The specific deposition process is to control the temperature of the reaction chamber at 620°C-720°C, use TMAl as the Al source, TMGa as the Ga source, TMIn as the In source, and PH3 as the P source, and grow an AlGaInP barrier layer with a thickness of 60Å-200Å and a GaInP well layer with a thickness of 30Å-80Å, with an alternating arrangement period of 8-18. In the present embodiment, the reaction chamber temperature is 680°C, the thickness of the formed AlGaInP barrier layer is 120Å, the thickness of the formed GaInP well layer is 50Å, and the period is 12.

[0061] The P-type semiconductor layer includes a P-AlGaInP waveguide layer, a P-AlInP confinement layer, a P-GaP window layer and a P-GaP ohmic contact layer which are arranged in sequence from bottom to top.

[0062] Furthermore, a P-AlGaInP waveguide layer is prepared on the active layer. The P-AlGaInP waveguide layer is based on AlGaAs. The specific deposition process is to control the reaction temperature at 600°C-700°C, use TMAl as the Al source, TMGa as the Ga source, and AsH3 as the As source, and grow a P-AlGaInP waveguide layer with a thickness of 100nm~300nm. In this embodiment, the reaction chamber temperature is 650°C, and the thickness of the formed P-AlGaInP waveguide layer is 200nm.

[0063] Furthermore, a P-AlInP confinement layer is prepared on the P-AlGaInP waveguide layer. The specific deposition process is as follows: the temperature of the reaction chamber is controlled at 700°C-800°C, TMAl is used as an Al source, TMIn is used as an In source, PH3 is used as a P source, and Mg or Zn is used as a dopant to grow a P-AlGaInP confinement layer with a thickness of 100nm-400nm, wherein the doping concentration of Mg or Zn is 1×10 17 atoms / cm 3 ~1×10 19 atoms / cm 3 In this embodiment, the reaction chamber temperature is 750°C, the thickness of the formed P-AlGaInP confinement layer is 250nm, and Mg element doping is selected, and the doping concentration of Mg element is 1×10 18 atoms / cm 3 .

[0064] Furthermore, a P-GaP window layer is prepared on the P-AlInP confinement layer. The specific deposition process is as follows: the reaction chamber temperature is controlled at 780°C to 850°C, and the reaction chamber pressure is controlled at 40 mbar to 60 mbar. TMGa is used as a Ga source, PH3 is used as a P source, and CP2Mg is used as a dopant to grow a P-GaP window layer with a thickness of 3 um to 50 um, wherein the Mg doping concentration is 1×10 18 atoms / cm 3 ~1×10 19 atoms / cm 3 In this embodiment, the reaction chamber temperature is 800°C, the reaction chamber pressure is 50 mbar, the thickness of the formed P-GaP window layer is 30 um, and the doping concentration of the Mg element is 1×10 18 atoms / cm 3 .

[0065] Furthermore, a P-GaP ohmic contact layer is prepared on the P-GaP window layer, wherein the P-GaP ohmic contact layer is doped with a C element. The specific deposition process is as follows: the temperature of the reaction chamber is controlled at 580°C to 630°C, TMGa is used as a Ga source, PH3 is used as a P source, and the doping concentration of the C element is 1×10 20 atoms / cm 3 ~1×10 22 atoms / cm 3 , a P-GaP ohmic contact layer with a thickness of 30nm-150nm is grown. In this embodiment, the reaction chamber temperature is 600°C, and the doping concentration of the C element is 1×10 20 atoms / cm 3 The thickness of the formed P-GaP ohmic contact layer is 70nm.

[0066] In this way, an AlGaInP-based epitaxial wafer is prepared. N electrodes and P electrodes are arranged at both ends of the AlGaInP-based epitaxial wafer to prepare an LED chip.

[0067] The LED chip prepared by the above preparation method has a brightness improved by 0.75% compared with the LED chip in the prior art. The present invention also provides multiple sets of experimental data to verify the feasibility of this solution, as shown in the following table:

[0068]

[0069] It should be noted that the table shows (Al x Ga 1-x ) 0.5 In 0.5 P first sublayer / (Al Y Ga1-Y ) 0.5 In 0.5 The epitaxial wafer used in the LED chip in the comparative example in the table is different from the AlGaInP-based epitaxial wafer in the present invention only in the N-type semiconductor layer. The N-type semiconductor layer of the AlGaInP-based epitaxial wafer in the present invention includes an N-AlInP confinement layer, an N-AlGaInP waveguide layer and a resonant potential well layer arranged in sequence from bottom to top, while the epitaxial wafer in the comparative example only includes an N-AlInP confinement layer and an N-AlGaInP waveguide layer arranged in sequence from bottom to top, and does not have a resonant potential well layer;

[0070] It can be seen that the LED chip prepared by the above preparation method of the present invention can improve the brightness by at least 0.29% and at most 0.75% compared with the LED chip in the prior art.

[0071] In summary, the AlGaInP-based epitaxial wafer and LED chip prepared by the preparation method of the AlGaInP-based epitaxial wafer in the above embodiment of the present invention form a charge imbalance resonant tunnel at the resonant potential well layer, in which electrons are captured and confined, and tunnel into the active layer multiple times along the growth direction, which greatly increases the number of electrons entering the active layer, improves the internal quantum efficiency, and suppresses the problem of leakage of the device caused by electrons reaching the P-type layer, thereby enhancing the lifespan during use; reducing the speed of electron movement can produce more radiation recombination with holes in the light-emitting area, reducing the risk of the epitaxial wafer being broken down; making a structure with alternating growth of different potential barriers, increasing the lateral expansion of electrons, and increasing the effective radiation recombination area of ​​the light-emitting area; at the same time, the thickness of the P-side electron resistance layer can be reduced, saving raw materials and growth time costs; thereby solving the problem of lower internal quantum efficiency of quaternary AlGaInP LEDs with shorter wavelengths.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0073] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An AlGaInP-based epitaxial wafer, characterized in that: The invention comprises, from bottom to top, a substrate, an intermediate layer, an N-type semiconductor layer, an active layer and a P-type semiconductor layer, wherein the N-type semiconductor layer comprises a resonant potential well layer arranged close to the active layer, the resonant potential well layer comprises a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer, the potential barrier sublayer is a non-doped AlGaInP sublayer, and the potential well sublayer comprises (AlGaInP) arranged periodically and alternately from bottom to top. x Ga 1-x ) 0.5 In 0.5 P first sublayer and (Al Y Ga 1-Y ) 0.5 In 0.5 P second sublayer, the (Al x Ga 1-x ) 0.5 In 0.5 The bandgap width of the first sublayer of P gradually decreases from bottom to top. Y Ga 1-Y ) 0.5 In 0.5 The potential barrier of the second sublayer of P is higher than (Al x Ga 1-x ) 0.5 In 0.5 P the potential barrier of the first sublayer; the (Al x Ga 1-x ) 0.5 In 0.5 P first sublayer and the (Al Y Ga 1-Y ) 0.5 In 0.5 The stacking period of the second sublayer of P is 2 to 8; in the (Al x Ga 1-x ) 0.5 In 0.5 In the first sublayer, 0≤x≤0.7, in the (Al Y Ga 1-Y ) 0.5 In 0.5 In the second sublayer, 0.7 <Y<1。 2. The AlGaInP-based epitaxial wafer according to claim 1, characterized in that: The growth thickness of the barrier sublayer is 10Å~100Å, and the wide well thickness of the potential well sublayer is ≥200Å.

3. The AlGaInP-based epitaxial wafer according to claim 1, characterized in that: The intermediate layer includes a buffer layer and a Bragg reflection layer which are sequentially arranged from bottom to top.

4. The AlGaInP-based epitaxial wafer according to claim 1, characterized in that: The N-type semiconductor layer further includes an N-AlInP limiting layer and an N-AlGaInP waveguide layer which are sequentially arranged from bottom to top, and the resonant potential well layer is located between the N-AlGaInP waveguide layer and the active layer.

5. The AlGaInP-based epitaxial wafer according to claim 1, characterized in that: The P-type semiconductor layer includes a P-AlGaInP waveguide layer, a P-AlInP confinement layer, a P-GaP window layer and a P-GaP ohmic contact layer which are arranged in sequence from bottom to top.

6. A method for preparing an AlGaInP-based epitaxial wafer, characterized in that: The steps include: providing a substrate; Depositing an intermediate layer and an N-type semiconductor layer in sequence on the substrate; The N-type semiconductor layer includes a resonant potential well layer, the resonant potential well layer includes a potential well sublayer and a potential barrier sublayer arranged at both ends of the potential well sublayer, the potential barrier sublayer is a non-doped AlGaInP sublayer, and the potential well sublayer includes (AlGaInP) arranged periodically and alternately from bottom to top. x Ga 1-x ) 0.5 In 0.5 P first sublayer and (Al Y Ga 1-Y ) 0.5 In 0.5 P second sublayer, the (Al x Ga 1-x ) 0.5 In 0.5 The bandgap width of the first sublayer of P gradually decreases from bottom to top. Y Ga 1-Y ) 0.5 In 0.5 The potential barrier of the second sublayer of P is higher than (Al x Ga 1-x ) 0.5 In 0.5 P potential barrier of the first sublayer; Depositing an active layer and a P-type semiconductor layer in sequence on the barrier sublayer; The x Ga 1-x ) 0.5 In 0.5 P first sublayer and the (Al Y Ga 1-Y ) 0.5 In 0.5 The stacking period of the second sublayer of P is 2 to 8; in the (Al x Ga 1-x ) 0.5 In 0.5 In the first sublayer, 0≤x≤0.7, in the (Al Y Ga 1-Y ) 0.5 In 0.5 In the second sublayer, 0.7 <Y<1。 7. The method for preparing an AlGaInP-based epitaxial wafer according to claim 6, characterized in that: When preparing the resonant potential well layer, the reaction temperature is 600°C-700°C, the growth thickness of the barrier sublayer is 10Å-100Å, and the wide well thickness of the potential well sublayer is ≥200Å.

8. An LED, characterized in that: The invention comprises the AlGaInP-based epitaxial wafer as described in any one of claims 1 to 5.

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