CN118231540A - Light-emitting diode epitaxial wafer, preparation method thereof and light-emitting diode - Google Patents

Abstract

The invention discloses a light-emitting diode epitaxial wafer, a preparation method thereof and a light-emitting diode, and relates to the technical field of semiconductors. The light-emitting diode epitaxial wafer comprises a substrate, and a buffer layer, an N-type semiconductor layer, a stress release layer, a multiple quantum well light-emitting layer, an electron blocking layer and a P-type semiconductor layer which are sequentially laminated on the substrate; the multi-quantum well light-emitting layer comprises a quantum well layer and a composite quantum barrier layer which are periodically and alternately laminated; the composite quantum barrier layer comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer which are sequentially stacked; the first quantum barrier layer is a first AlInGaN layer, the second quantum barrier layer is a Si doped GaN layer, and the third quantum barrier layer is a second AlInGaN layer; the forbidden bandwidths of the first quantum barrier layer and the third quantum barrier layer are larger than those of the second quantum barrier layer. By implementing the invention, the luminous efficiency of the light emitting diode can be improved.

Description

Light-emitting diode epitaxial wafer and preparation method thereof, and light-emitting diode

Technical Field

The present invention relates to the field of semiconductor technology, and in particular to a light emitting diode epitaxial wafer and a preparation method thereof, and a light emitting diode.

Background technique

GaN-based LED devices generally use InGaN/GaN multiple quantum wells as the light-emitting active area, but there is a large lattice mismatch between the InGaN well layer material and the GaN barrier layer material. The InGaN well layer will be subjected to compressive stress from the GaN barrier layer. The polarization effect caused by the compressive stress will cause serious band bending deformation inside the InGaN quantum well, causing the wave functions of electrons and holes to separate in space, resulting in low recombination radiation efficiency in the light-emitting active area, limiting the luminous efficiency of GaN-based LED devices.

Summary of the invention

The technical problem to be solved by the present invention is to provide a light-emitting diode epitaxial wafer, reduce the stress on the quantum well layer, and at the same time enhance the carrier confinement effect, so as to enhance the radiation recombination efficiency in the multi-quantum well light-emitting layer, thereby improving the light-emitting efficiency of the light-emitting diode.

The technical problem to be solved by the present invention is also to provide a method for preparing a light emitting diode epitaxial wafer, and the prepared light emitting diode epitaxial wafer has high luminous efficiency.

In order to achieve the above technical effect, the present invention provides a light-emitting diode epitaxial wafer, comprising a substrate, and a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer, an electron blocking layer and a P-type semiconductor layer sequentially stacked on the substrate;

The multi-quantum well light-emitting layer comprises quantum well layers and composite quantum barrier layers that are periodically and alternately stacked; the composite quantum barrier layer comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer that are stacked in sequence; the first quantum barrier layer is a first AlInGaN layer, the second quantum barrier layer is a Si-doped GaN layer, and the third quantum barrier layer is a second AlInGaN layer;

The bandgap widths of the first quantum barrier layer and the third quantum barrier layer are both greater than the bandgap width of the second quantum barrier layer.

As an improvement of the above technical solution, the first AlInGaN layer is a Si-doped AlInGaN layer, with an Al component ratio of 0.01-0.66, an In component ratio of 0.01-0.5, a thickness of 0.5nm-3.6nm, and a Si doping concentration of 3.18×10 ¹⁶ cm ^-3 -5.26×10 ¹⁷ cm ^-3 .

As an improvement of the above technical solution, the thickness of the second quantum barrier layer is 5 nm to 15 nm, and the Si doping concentration is 1.05×10 ¹⁷ cm ^-3 to 2.36×10 ¹⁸ cm ^-3 .

As an improvement of the above technical solution, the second AlInGaN layer is a Si-doped AlInGaN layer, with an Al component ratio of 0.01-0.66, an In component ratio of 0.01-0.5, a thickness of 0.5nm-3.6nm, and a Si doping concentration of 3.18×10 ¹⁶ cm ^-3 -5.26×10 ¹⁷ cm ^-3 .

As an improvement of the above technical solution, the quantum well layer is an unintentionally doped InGaN layer, the In component ratio is 0.01 to 0.42, and the thickness is 2.2 nm to 4.8 nm.

As an improvement of the above technical solution, the lattice constants of the first quantum barrier layer and the third quantum barrier layer in the horizontal direction are both greater than or equal to the lattice constant of the quantum well layer in the horizontal direction.

As an improvement of the above technical solution, the number of periods of the multi-quantum well light-emitting layer is 3-15.

Correspondingly, the present invention also discloses a method for preparing a light-emitting diode epitaxial wafer, which is used to prepare the light-emitting diode epitaxial wafer, and comprises the following steps:

Providing a substrate, and sequentially growing a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer, an electron blocking layer, and a P-type semiconductor layer on the substrate;

The multi-quantum well light-emitting layer comprises quantum well layers and composite quantum barrier layers that are periodically and alternately stacked; the composite quantum barrier layer comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer that are stacked in sequence; the first quantum barrier layer is a first AlInGaN layer, the second quantum barrier layer is a Si-doped GaN layer, and the third quantum barrier layer is a second AlInGaN layer;

The bandgap widths of the first quantum barrier layer and the third quantum barrier layer are both greater than the bandgap width of the second quantum barrier layer.

As an improvement of the above technical solution, in the composite quantum barrier layer, the growth temperature of the first quantum barrier layer is 800°C to 920°C, and the growth pressure is 90Torr to 360Torr; the growth temperature of the second quantum barrier layer is 820°C to 930°C, and the growth pressure is 90Torr to 360Torr; the growth temperature of the third quantum barrier layer is 800°C to 920°C, and the growth pressure is 90Torr to 360Torr;

The growth temperature of the quantum well layer is 620° C. to 880° C., and the growth pressure is 90 Torr to 360 Torr.

Correspondingly, the present invention also discloses a light emitting diode, comprising the light emitting diode epitaxial wafer mentioned above.

The implementation of the embodiments of the present invention has the following beneficial effects:

1. The multi-quantum well light-emitting layer of the present invention comprises quantum well layers and composite quantum barrier layers that are periodically and alternately stacked, and the composite quantum barrier layer comprises a first quantum barrier layer, a second quantum barrier layer, and a third quantum barrier layer that are stacked in sequence, the first quantum barrier layer and the third quantum barrier layer are both AlInGaN layers, the second quantum barrier layer is a Si-doped GaN layer, and the bandgap widths of the first quantum barrier layer and the third quantum barrier layer are both greater than the bandgap width of the quantum well layer. By controlling the bandgap widths of the first quantum barrier layer, the third quantum barrier layer, and the quantum well layer, carriers can be confined in the quantum well layer to participate in light emission, thereby improving the radiation recombination efficiency in the multi-quantum well light-emitting layer.

2. By controlling the composition ratio of the AlInGaN quaternary material, the lattice constants of the first quantum barrier layer, the third quantum barrier layer and the quantum well layer are matched, which greatly reduces the dislocations caused by lattice mismatch in the quantum well layer, and significantly reduces the band bending phenomenon in the multi-quantum well light-emitting layer region caused by the stress on the quantum well layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a light emitting diode epitaxial wafer in an embodiment of the present invention;

FIG2 is a schematic diagram of the structure of a multi-quantum well light-emitting layer of a light-emitting diode epitaxial wafer in an embodiment of the present invention;

FIG. 3 is a flow chart of a method for preparing a light emitting diode epitaxial wafer in an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with specific embodiments.

As shown in Figures 1 and 2, an embodiment of the present invention provides a light-emitting diode epitaxial wafer, including a substrate 100, and a buffer layer 200, an N-type semiconductor layer 300, a stress release layer 400, a multi-quantum well light-emitting layer 500, an electron blocking layer 600 and a P-type semiconductor layer 700 stacked in sequence on the substrate 100.

The multi-quantum well light-emitting layer 500 includes periodically alternately stacked quantum well layers 510 and composite quantum barrier layers 520. Specifically, the composite quantum barrier layer 520 includes a first quantum barrier layer 521, a second quantum barrier layer 522, and a third quantum barrier layer 523 stacked in sequence; the first quantum barrier layer 521 is a first AlInGaN layer, the second quantum barrier layer 522 is a Si-doped GaN layer, and the third quantum barrier layer 523 is a second AlInGaN layer. The bandgap widths of the first quantum barrier layer 521 and the third quantum barrier layer 523 are both greater than the bandgap width of the second quantum barrier layer 522. The InGaN of the second quantum barrier layer 522 is the main material for luminescence in the multi-quantum well light-emitting layer. By controlling the bandgap widths of the first quantum barrier layer 521 and the third quantum barrier layer 523 to be greater than the bandgap width of the quantum barrier layer 520, the confinement effect of carriers can be enhanced, and the carriers can be confined to the quantum well layer 510 to participate in luminescence, thereby improving the radiation recombination efficiency in the multi-quantum well light-emitting layer 500, thereby improving the luminescence efficiency of the light-emitting diode.

In one embodiment, the first AlInGaN layer is a Si-doped AlInGaN layer, and the Al component ratio is 0.01 to 0.66, and is exemplarily 0.01, 0.08, 0.2, 0.3, 0.4 or 0.66, but not limited thereto. The In component ratio of the first AlInGaN layer is 0.01 to 0.5, and is exemplarily 0.01, 0.05, 0.1, 0.2, 0.3 or 0.5, but not limited thereto. Too high Al component ratio and In component ratio will lead to reduced crystal quality. The thickness of the first AlInGaN layer is 0.5nm to 3.6nm, and is exemplarily 0.5nm, 0.8nm, 1nm, 2nm, 3nm or 3.6nm, but not limited thereto. The Si doping concentration of the first AlInGaN layer is 3.18×10 ¹⁶ cm ^-3 to 5.26×10 ¹⁷ cm ^-3 , exemplarily 3.18×10 ¹⁶ cm ^-3 , 5×10 ¹⁶ cm ^-3 , 8×10 ¹⁶ cm ^-3 , 1×10 ¹⁶ cm ^-3 , 2.5×10 ¹⁷ cm ^-3 or 5.26×10 ¹⁷ cm ^-3 , but not limited thereto.

In one embodiment, the second quantum barrier layer is a Si-doped GaN layer, and doping with Si elements can improve conductivity, which is beneficial to reducing the resistance of the multi-quantum well active region and further reducing the operating voltage of the LED. The thickness of the second quantum barrier layer is 5nm to 15nm, and is exemplarily 5nm, 8nm, 10nm, 12nm, 14nm or 15nm, but is not limited thereto. The Si doping concentration of the second quantum barrier layer is 1.05×10 ¹⁷ cm ^-3 to 2.36×10 ¹⁸ cm ^-3 , exemplarily 1.05×10 ¹⁷ cm ^-3 , 2.5×10 ¹⁷ cm ^-3 , 5×10 ¹⁷ cm ^-3 , 8×10 ¹⁷ cm ^-3 , 1×10 ¹⁸ cm ^-3 or 2.36×10 ¹⁸ cm ^-3 , but not limited thereto. The Si doping concentration of the second quantum barrier layer is greater than the Si doping concentrations of the first quantum barrier layer and the third quantum barrier layer. The first quantum barrier layer and the third quantum barrier layer are in contact with the quantum well layer. Setting a lower Si doping concentration is beneficial to improving the recombination radiation efficiency.

In one embodiment, the second AlInGaN layer is a Si-doped AlInGaN layer, and the Al component ratio is 0.01 to 0.66, and 0.01, 0.08, 0.2, 0.3, 0.4 or 0.66 are exemplary, but not limited to this. The In component ratio of the first AlInGaN layer is 0.01 to 0.5, and 0.01, 0.05, 0.1, 0.2, 0.3 or 0.5 are exemplary, but not limited to this. Too high Al component ratio and In component ratio will lead to reduced crystal quality. The thickness of the first AlInGaN layer is 0.5nm to 3.6nm, and 0.5nm, 0.8nm, 1nm, 2nm, 3nm or 3.6nm are exemplary, but not limited to this. The Si doping concentration of the first AlInGaN layer is 3.18×10 ¹⁶ cm ^-3 to 5.26×10 ¹⁷ cm ^-3 , exemplarily 3.18×10 ¹⁶ cm ^-3 , 5×10 ¹⁶ cm ^-3 , 8×10 ¹⁶ cm ^-3 , 1×10 ¹⁶ cm ^-3 , 2.5×10 ¹⁷ cm ^-3 or 5.26×10 ¹⁷ cm ^-3 , but not limited thereto.

In one embodiment, the lattice constants of the first quantum barrier layer and the third quantum barrier layer in the horizontal direction are both greater than or equal to the lattice constant of the quantum well layer in the horizontal direction, and the lattice constants of the first quantum barrier layer, the third quantum barrier layer and the quantum well layer are matched by controlling the composition ratio of the AlInGaN quaternary material. More preferably, the lattice constants of the first quantum barrier layer and the third quantum barrier layer in the horizontal direction are both equal to the lattice constant of the quantum well layer in the horizontal direction, which can greatly reduce the stress on the quantum well layer, significantly reduce the band bending phenomenon in the multi-quantum well light-emitting layer region, and at the same time greatly reduce the dislocation of the quantum well layer due to lattice mismatch, thereby improving the quality of the multi-quantum well light-emitting layer.

In one embodiment, the number of periods of the multi-quantum well light-emitting layer is 3 to 15, exemplarily 3, 5, 8, 10, 12 or 15, but not limited thereto. The quantum well layer is an unintentionally doped InGaN layer, and the In component ratio is 0.01 to 0.42, exemplarily 0.01, 0.05, 0.08, 0.1, 0.2 or 0.42, but not limited thereto. The thickness of the quantum well layer is 2.2 nm to 4.8 nm, exemplarily 2.2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm or 4.8 nm, but not limited thereto.

In addition to the above-mentioned multi-quantum well light-emitting layer, the other layered structures of the present invention are characterized as follows:

The substrate 100 may be selected from sapphire substrate, AlN substrate, Si substrate, and SiC substrate. In one embodiment, the substrate 100 is a sapphire substrate, which is the most commonly used substrate material at present. The sapphire substrate has the advantages of mature preparation technology, low price, easy cleaning and processing, and good stability at high temperature.

The buffer layer 200 is an AlN buffer layer or an AlGaN buffer layer, and the thickness of the buffer layer 200 is 10nm to 100nm. In one embodiment, the buffer layer 200 is an AlN buffer layer, and the use of the AlN buffer layer provides a nucleation center with the same orientation as the substrate, releases the stress generated by the lattice mismatch between GaN and the substrate and the thermal stress generated by the mismatch of thermal expansion coefficients, provides a flat nucleation surface for further growth, reduces the contact angle of its nucleation growth, and enables the island-like growth of GaN grains to be connected to a surface within a smaller thickness, and transforms into two-dimensional epitaxial growth.

The N-type semiconductor layer 300 includes an undoped GaN layer and an N-type GaN layer stacked in sequence, the undoped GaN layer has a thickness of 1 μm to 3 μm, the N-type GaN layer has a thickness of 1 μm to 3 μm, and the doping concentration is 5×10 ¹⁷ cm ^-3 to 1×10 ¹⁹ cm ^-3 .

The stress release layer 400 is an AlGaN stress release layer with a thickness of 50 nm to 100 nm.

The electron blocking layer 600 is an AlInGaN layer with a thickness of 10 nm to 100 nm.

The P-type semiconductor layer 700 is a P-type GaN layer with a thickness of 20 nm to 200 nm and a doping concentration of 1×10 ¹⁹ cm ^-3 to 5×10 ²⁰ cm ^-3 . Too high a doping concentration will damage the crystal quality, while too low a doping concentration will affect the hole concentration.

As shown in FIG3 , the present invention further discloses a method for preparing a light emitting diode epitaxial wafer, comprising the following steps:

S1 provides a substrate.

S2 sequentially grows a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer, an electron blocking layer, and a P-type semiconductor layer on the substrate. The epitaxial structure can be grown by MOCVD, MBE, PLD, or VPE, but is not limited thereto. Specifically, S2 includes the following steps:

S21, growth buffer layer;

The AlN buffer layer is grown by PVD at a growth temperature of 500°C to 600°C, a power of 3000W to 5000W, Ar as the sputtering gas, _N2 as the precursor, and Al as the sputtering target. The substrate coated with the AlN buffer layer is transferred to MOCVD and pretreated in a _H2 atmosphere for 1min to 10min at a pretreatment temperature of 1000°C to 1200°C.

S22, growing an N-type semiconductor layer;

The undoped GaN layer is grown by MOCVD at a temperature of 1100°C to 1150°C and a pressure of 100Torr to 500Torr, with _NH3 as the N source and TMGa as the Ga source. The N-type GaN layer is grown by MOCVD at a temperature of 1000°C to 1300°C and a pressure of 100Torr to 500Torr, with _NH3 as the N source, TMGa as the Ga source and _SiH4 as the N-type doping source.

S23, growing a stress release layer;

The AlGaN stress release layer is grown by MOCVD at a temperature of 800°C to 950°C and a pressure of 100Torr to 500Torr, with _NH3 as the N source, TMGa as the Ga source and TMAl as the Al source.

S24, growing a multi-quantum well light-emitting layer;

The quantum well layer is grown by MOCVD at a temperature of 620°C to 880°C and a pressure of 90 Torr to 360 Torr, with NH ₃ as the N source, TEGa as the Ga source, and TMIn as the In source. The composite quantum barrier layer is grown by MOCVD at a temperature of 800°C to 930°C and a pressure of 90 Torr to 360 Torr. The quantum well layer and the composite quantum barrier layer are repeatedly stacked to grow periodically. Specifically, the preparation of the composite quantum barrier layer includes the following steps:

S241, growing a first quantum barrier layer;

MOCVD growth is adopted, the temperature is 800℃～920℃, the pressure is 90Torr～360Torr, _NH3 is used as N source, TMGa is used as Ga source, TMAl is used as Al source, TMIn is used as In source, and _SiH4 is used as N-type doping source.

S242, growing a second quantum barrier layer;

MOCVD growth is adopted, the temperature is 820℃～930℃, the pressure is 90Torr～360Torr, _NH3 is used as N source, TMGa is used as Ga source, and _SiH4 is used as N-type doping source.

S243, growing a third quantum barrier layer;

MOCVD growth is adopted, the temperature is 800℃～920℃, the pressure is 90Torr～360Torr, _NH3 is used as N source, TMGa is used as Ga source, TMAl is used as Al source, TMIn is used as In source, and _SiH4 is used as N-type doping source.

S25, growing an electron blocking layer;

The AlInGaN electron blocking layer is grown by MOCVD at a temperature of 1000°C to 1100°C and a pressure of 100Torr to 300Torr, with _NH3 as the N source, TMAl as the Al source, TMGa as the Ga source and TMIn as the In source.

S26, growing a P-type semiconductor layer;

The P-type GaN layer is grown by MOCVD at a temperature of 1000°C to 1100°C and a pressure of 100Torr to 600Torr, with NH ₃ as the N source, TMGa as the Ga source, and CP ₂ Mg as the P-type doping source.

The present invention is further described below with reference to specific embodiments.

Example 1

This embodiment provides a light-emitting diode epitaxial wafer, a substrate, and a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer, an electron blocking layer, and a P-type semiconductor layer stacked in sequence on the substrate.

The substrate is a sapphire substrate.

The buffer layer is an AlN buffer layer with a thickness of 50 nm.

The N-type semiconductor layer includes a non-doped GaN layer and an N-type GaN layer stacked in sequence, the non-doped GaN layer has a thickness of 2 μm; the N-type GaN layer has a thickness of 2 μm, and the doping concentration of Si is 2.5×10 ¹⁹ cm ^-3 .

The stress release layer is an AlGaN stress release layer with a thickness of 60 nm.

The multi-quantum well light-emitting layer includes quantum well layers and composite quantum barrier layers that are periodically and alternately stacked, with a period number of 3. The composite quantum barrier layer includes a first quantum barrier layer, a second quantum barrier layer, and a third quantum barrier layer that are stacked in sequence. Among them, the first quantum barrier layer is the first AlInGaN layer, the Al component accounts for 0.3, the In component accounts for 0.4, the thickness is 1nm, and the Si doping concentration is 2×10 ¹⁶ cm ^-3 ; the second quantum barrier layer is a Si-doped GaN layer, the thickness is 3nm, and the Si doping concentration is 1×10 ¹⁷ cm ^-3 ; the third quantum barrier layer is the second AlInGaN layer, the Al component accounts for 0.3, the In component accounts for 0.4, the thickness is 1nm, and the Si doping concentration is 2×10 ¹⁶ cm ^-3 . The quantum well layer is an unintentionally doped InGaN layer, the In component accounts for 0.2, and the thickness is 3.8nm.

The electron blocking layer is an AlInGaN electron blocking layer with a thickness of 30 nm.

The P-type semiconductor layer is a P-type GaN layer with a thickness of 100 nm and a Mg doping concentration of 5×10 ¹⁹ cm ^-3 .

The method for preparing the light emitting diode epitaxial wafer comprises the following steps:

S1 provides a substrate.

S2 sequentially grows a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer, an electron blocking layer and a P-type semiconductor layer on the substrate. Specifically, S2 includes the following steps:

S21, growth buffer layer;

The AlN buffer layer was grown by PVD at a growth temperature of 500°C, a power of 4000W, Ar as the sputtering gas, _N2 as the precursor, and Al as the sputtering target. The substrate with the AlN buffer layer was transferred to MOCVD and pretreated in a _H2 atmosphere for 6 minutes at a pretreatment temperature of 1100°C.

S22, growing an N-type semiconductor layer;

The undoped GaN layer was grown by MOCVD at a temperature of 1120°C and a pressure of 200Torr, with _NH3 as the N source and TMGa as the Ga source. The N-type GaN layer was grown by MOCVD at a temperature of 1200°C and a pressure of 200Torr, with _NH3 as the N source, TMGa as the Ga source and _SiH4 as the N-type doping source.

S23, growing a stress release layer;

The AlGaN stress release layer is grown by MOCVD at a temperature of 900°C and a pressure of 150 Torr, with _NH3 as the N source, TMGa as the Ga source, and TMAl as the Al source.

S24, growing a multi-quantum well light-emitting layer;

The quantum well layer is grown by MOCVD at a temperature of 780°C and a pressure of 200 Torr, with NH ₃ as the N source, TEGa as the Ga source, and TMIn as the In source. The composite quantum barrier layer is grown by MOCVD. The quantum well layer and the composite quantum barrier layer are repeatedly stacked and periodically grown. Specifically, the preparation of the composite quantum barrier layer includes the following steps:

S241, growing a first quantum barrier layer;

MOCVD was used for growth at a temperature of 880°C and a pressure of 150 Torr, with NH ₃ as the N source, TMGa as the Ga source, TMAl as the Al source, and TMIn as the In source.

S242, growing a second quantum barrier layer;

The MOCVD growth was carried out at a temperature of 900°C and a pressure of 150 Torr, with NH ₃ as the N source, TMGa as the Ga source, and TMIn as the In source.

S243, growing a third quantum barrier layer;

The MOCVD growth was carried out at a temperature of 880°C and a pressure of 150 Torr, with NH ₃ as the N source, TMGa as the Ga source, TMAl as the Al source, and TMIn as the In source.

S25, growing an electron blocking layer;

The AlInGaN electron blocking layer is grown by MOCVD at a temperature of 1000°C and a pressure of 200 Torr, with _NH3 as the N source, TMAl as the Al source, TMGa as the Ga source, and TMIn as the In source.

S26, growing a P-type semiconductor layer;

The P-type GaN layer is grown by MOCVD at a temperature of 1050°C and a pressure of 200 Torr, with NH ₃ as the N source, TMGa as the Ga source, and CP ₂ Mg as the P-type doping source.

Example 2

This embodiment provides a light-emitting diode epitaxial wafer, and the multi-quantum well light-emitting layer includes quantum well layers and composite quantum barrier layers that are periodically and alternately stacked, and the number of periods is 10. The composite quantum barrier layer includes a first quantum barrier layer, a second quantum barrier layer, and a third quantum barrier layer that are stacked in sequence. Among them, the first quantum barrier layer is a first AlInGaN layer, the Al component accounts for 0.14, the In component accounts for 0.23, the thickness is 0.8nm, and the Si doping concentration is 5×10 ¹⁶ cm ^-3 ; the second quantum barrier layer is a Si-doped GaN layer, the thickness is 5nm, and the Si doping concentration is 5×10 ¹⁷ cm ^-3 ; the third quantum barrier layer is a second AlInGaN layer, the Al component accounts for 0.14, the In component accounts for 0.23, the thickness is 0.8nm, and the Si doping concentration is 5×10 ¹⁶ cm ^-3 . The quantum well layer is an unintentionally doped InGaN layer, the In component accounts for 0.2, and the thickness is 3.8nm.

Example 3

This embodiment provides a light-emitting diode epitaxial wafer, and the multi-quantum well light-emitting layer includes a periodically alternately stacked composite quantum well layer and a quantum barrier layer, and the number of periods is 10. The composite quantum well layer includes a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer stacked in sequence. Among them, the first quantum barrier layer is a first AlInGaN layer, the Al component accounts for 0.05, the In component accounts for 0.23, the thickness is 0.8nm, and the Si doping concentration is 5×10 ¹⁶ cm ^-3 ; the second quantum barrier layer is a Si-doped GaN layer, the thickness is 10nm, and the Si doping concentration is 5×10 ¹⁷ cm ^-3 ; the third quantum barrier layer is a second AlInGaN layer, the Al component accounts for 0.14, the In component accounts for 0.23, the thickness is 0.8nm, and the Si doping concentration is 5×10 ¹⁶ cm ^-3 . The quantum well layer is an unintentionally doped InGaN layer, the In component accounts for 0.2, and the thickness is 3.8nm.

Example 4

This embodiment provides a light-emitting diode epitaxial wafer, and the multi-quantum well light-emitting layer includes a periodically alternately stacked composite quantum well layer and a quantum barrier layer, and the number of periods is 10. The composite quantum well layer includes a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer stacked in sequence. Among them, the first quantum barrier layer is a first AlInGaN layer, the Al component accounts for 0.14, the In component accounts for 0.23, the thickness is 0.8nm, and the Si doping concentration is 5×10 ¹⁶ cm ^-3 ; the second quantum barrier layer is a Si-doped GaN layer, the thickness is 10nm, and the Si doping concentration is 5×10 ¹⁷ cm ^-3 ; the third quantum barrier layer is a second AlInGaN layer, the Al component accounts for 0.05, the In component accounts for 0.23, the thickness is 0.8nm, and the Si doping concentration is 5×10 ¹⁶ cm ^-3 . The quantum well layer is an unintentionally doped InGaN layer, the In component accounts for 0.2, and the thickness is 3.8nm.

Example 5

This embodiment provides a light-emitting diode epitaxial wafer, and the multi-quantum well light-emitting layer includes quantum well layers and composite quantum barrier layers that are periodically and alternately stacked, and the number of periods is 10. The composite quantum barrier layer includes a first quantum barrier layer, a second quantum barrier layer, and a third quantum barrier layer that are stacked in sequence. Among them, the first quantum barrier layer is a first AlInGaN layer, the Al component accounts for 0.05, the In component accounts for 0.23, the thickness is 0.8nm, and the Si doping concentration is 5×10 ¹⁶ cm ^-3 ; the second quantum barrier layer is a Si-doped GaN layer, the thickness is 10nm, and the Si doping concentration is 5×10 ¹⁷ cm ^-3 ; the third quantum barrier layer is a second AlInGaN layer, the Al component accounts for 0.05, the In component accounts for 0.23, the thickness is 0.8nm, and the Si doping concentration is 5×10 ¹⁶ cm ^-3 . The quantum well layer is an unintentionally doped InGaN layer, the In component accounts for 0.2, and the thickness is 3.8nm.

Comparative Example 1

This comparative example provides a light-emitting diode epitaxial wafer, which is different from Example 1 in that the multi-quantum well light-emitting layer includes periodically alternately stacked InGaN quantum well layers and GaN quantum barrier layers. Accordingly, the preparation method does not include the preparation of the first quantum barrier layer and the second quantum barrier layer. The rest is the same as Example 1.

Comparative Example 2

This comparative example provides a light-emitting diode epitaxial wafer, which is different from Example 1 in that the composite quantum barrier layer includes a first quantum barrier layer and a second quantum barrier layer stacked in sequence. Accordingly, the preparation method does not include the preparation of the third quantum barrier layer. The rest is the same as Example 1.

Comparative Example 3

This comparative example provides a light-emitting diode epitaxial wafer, which is different from Example 1 in that the composite quantum barrier layer includes a second quantum barrier layer and a third quantum barrier layer stacked in sequence. Accordingly, the preparation method does not include the preparation of the first quantum barrier layer. The rest is the same as Example 1.

Performance Testing:

The light-emitting diode epitaxial wafers prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were made into 3mil×5mil LED chips, and tested on the same LED spot tester at a current of 2mA, and the improvement in luminous efficacy of Examples 1 to 5, Comparative Example 2 and Comparative Example 3 compared to Comparative Example 1 was calculated.

The test results are shown in Table 1.

Table 1 Photoelectric performance test results of light-emitting diodes

It can be seen from the results in Table 1 that the multi-quantum well light-emitting layer structure of the present invention can significantly improve the light-emitting efficiency of the light-emitting diode.

The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims (10)

1. A light-emitting diode epitaxial wafer, characterized in that it comprises a substrate, and a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer, an electron blocking layer and a P-type semiconductor layer sequentially stacked on the substrate; The multi-quantum well light-emitting layer comprises quantum well layers and composite quantum barrier layers that are periodically and alternately stacked; the composite quantum barrier layer comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer that are stacked in sequence; the first quantum barrier layer is a first AlInGaN layer, the second quantum barrier layer is a Si-doped GaN layer, and the third quantum barrier layer is a second AlInGaN layer; The bandgap widths of the first quantum barrier layer and the third quantum barrier layer are both greater than the bandgap width of the second quantum barrier layer. 2. The light-emitting diode epitaxial wafer according to claim 1, characterized in that the first AlInGaN layer is a Si-doped AlInGaN layer, the Al component ratio is 0.01-0.66, the In component ratio is 0.01-0.5, the thickness is 0.5nm-3.6nm, and the Si doping concentration is 3.18×10 ¹⁶ cm ^-3 -5.26×10 ¹⁷ cm ^-3 . 3 . The light emitting diode epitaxial wafer according to claim 1 , wherein the thickness of the second quantum barrier layer is 5 nm to 15 nm, and the Si doping concentration is 1.05×10 ¹⁷ cm ⁻³ to 2.36×10 ¹⁸ cm ⁻³ . 4. The light-emitting diode epitaxial wafer according to claim 1, characterized in that the second AlInGaN layer is a Si-doped AlInGaN layer, with an Al component ratio of 0.01-0.66, an In component ratio of 0.01-0.5, a thickness of 0.5nm-3.6nm, and a Si doping concentration of 3.18× ^{1016cm -} 3-5.26× ^{1017cm -3} . 5. The light-emitting diode epitaxial wafer according to claim 1, wherein the quantum well layer is an unintentionally doped InGaN layer, the In component ratio is 0.01 to 0.42, and the thickness is 2.2 nm to 4.8 nm. 6 . The light emitting diode epitaxial wafer according to claim 1 , wherein the lattice constants of the first quantum barrier layer and the third quantum barrier layer in the horizontal direction are both greater than or equal to the lattice constant of the quantum well layer in the horizontal direction. 7 . The light emitting diode epitaxial wafer according to claim 1 , wherein the number of periods of the multi-quantum well light emitting layer is 3 to 15. 8. A method for preparing a light emitting diode epitaxial wafer, for preparing the light emitting diode epitaxial wafer according to any one of claims 1 to 7, characterized in that it comprises the following steps: Providing a substrate, and sequentially growing a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer, an electron blocking layer, and a P-type semiconductor layer on the substrate; The multi-quantum well light-emitting layer comprises quantum well layers and composite quantum barrier layers that are periodically and alternately stacked; the composite quantum barrier layer comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer that are stacked in sequence; the first quantum barrier layer is a first AlInGaN layer, the second quantum barrier layer is a Si-doped GaN layer, and the third quantum barrier layer is a second AlInGaN layer; The bandgap widths of the first quantum barrier layer and the third quantum barrier layer are both greater than the bandgap width of the second quantum barrier layer. 9. The method for preparing a light-emitting diode epitaxial wafer according to claim 8, characterized in that, in the composite quantum barrier layer, the growth temperature of the first quantum barrier layer is 800° C. to 920° C., and the growth pressure is 90 Torr to 360 Torr; the growth temperature of the second quantum barrier layer is 820° C. to 930° C., and the growth pressure is 90 Torr to 360 Torr; the growth temperature of the third quantum barrier layer is 800° C. to 920° C., and the growth pressure is 90 Torr to 360 Torr; The growth temperature of the quantum well layer is 620° C. to 880° C., and the growth pressure is 90 Torr to 360 Torr. 10. A light emitting diode, characterized in that the light emitting diode comprises the light emitting diode epitaxial wafer according to any one of claims 1 to 7.