CN113224211A - Ultraviolet light-emitting diode epitaxial wafer and manufacturing method thereof - Google Patents

Ultraviolet light-emitting diode epitaxial wafer and manufacturing method thereof Download PDF

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CN113224211A
CN113224211A CN202110294170.5A CN202110294170A CN113224211A CN 113224211 A CN113224211 A CN 113224211A CN 202110294170 A CN202110294170 A CN 202110294170A CN 113224211 A CN113224211 A CN 113224211A
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layer
sublayer
substrate
thickness
laser
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乔楠
李昱桦
刘源
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HC Semitek Suzhou Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/04—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
    • H01L33/06—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0062—Processes for devices with an active region comprising only III-V compounds
    • H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0062—Processes for devices with an active region comprising only III-V compounds
    • H01L33/0075—Processes for devices with an active region comprising only III-V compounds comprising nitride compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
    • H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen

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Abstract

The disclosure provides an ultraviolet light-emitting diode epitaxial wafer and a manufacturing method thereof, and belongs to the technical field of semiconductors. The ultraviolet light-emitting diode further comprises a laser stripping layer arranged between the substrate and the buffer layer, wherein the laser stripping layer comprises a first sublayer, a second sublayer and a third sublayer which are sequentially stacked on the substrate, the first sublayer is an InGaN layer, the second sublayer is an Al layer, and the third sublayer is an AlGaN layer. The ultraviolet light-emitting diode epitaxial wafer can realize stripping of the UVC LED substrate by adopting excimer laser with the wavelength of 248 nm.

Description

Ultraviolet light-emitting diode epitaxial wafer and manufacturing method thereof
Technical Field
The disclosure relates to the technical field of semiconductors, in particular to an ultraviolet light emitting diode epitaxial wafer and a manufacturing method thereof.
Background
In the current market, the commonly popular LED (light emitting diode) chip with a planar structure (the positive and negative electrodes are on the same side of the substrate) has the problems of small light emitting area, current crowding effect and the like, and the LED chip with a vertical structure (the positive and negative electrodes are on the upper and lower sides of the chip) can avoid the problems, thereby realizing high efficiency, high power and high brightness, and greatly improving the heat dissipation problem.
In order to fabricate a vertical structure LED chip, it is necessary to separate a substrate material (typically sapphire) in an LED substrate from an epitaxial layer, and then fabricate an electrode on a lift-off surface of the epitaxial layer. And the method for peeling the LED substrate by the laser peeling technology is a common method in the market at present.
In the traditional InGaN material blue light LED laser lift-off, excimer laser with the wavelength of 248nm is adopted to penetrate through a sapphire substrate to decompose a GaN material. The photon energy of excimer laser with the wavelength of 248nm is 4.34ev, the forbidden bandwidth of the GaN material is 3.4ev, and the forbidden bandwidth is smaller than the photon energy of the laser, so that the GaN material can absorb the photon energy of the excimer laser with the wavelength of 248nm, and the substrate stripping is realized. However, in the case of a UVC (ultraviolet C-band) LED, since the forbidden band width of AlN, which is an underlying material, is 6.2eV and is larger than the photon energy of laser light, AlN cannot absorb the photon energy of laser light, so that it is difficult to realize substrate lift-off of the UVC vertical structure LED using a laser lift-off technique.
Disclosure of Invention
The embodiment of the disclosure provides an ultraviolet light emitting diode epitaxial wafer and a manufacturing method thereof, which can realize stripping of a UVC LED substrate by adopting excimer laser with the wavelength of 248 nm. The technical scheme is as follows:
in one aspect, an ultraviolet light emitting diode epitaxial wafer is provided, the ultraviolet light emitting diode epitaxial wafer comprises a substrate, and a buffer layer, an N-type layer, an active layer and a P-type layer which are sequentially laminated on the substrate,
the ultraviolet light-emitting diode further comprises a laser stripping layer arranged between the substrate and the buffer layer, wherein the laser stripping layer comprises a first sublayer, a second sublayer and a third sublayer which are sequentially stacked on the substrate, the first sublayer is an InGaN layer, the second sublayer is an Al layer, and the third sublayer is an AlGaN layer.
Optionally, the thickness of the third sub-layer is greater than the thickness of the first sub-layer, and the thickness of the first sub-layer is greater than the thickness of the second sub-layer.
Optionally, the thickness of the first sub-layer is 5-50 nm, the thickness of the second sub-layer is 1-5 nm, and the thickness of the third sub-layer is 50-200 nm.
Optionally, the third sublayer is AlaGa1-aN layers, a is more than or equal to 0 and less than or equal to 0.33.
Optionally, the ultraviolet light emitting diode epitaxial wafer further comprises an insertion layer located between the substrate and the laser peeling layer, and the insertion layer is an AlN layer.
Optionally, the thickness of the first buffer layer is 10-30 nm.
Optionally, the buffer layer is an AlGaN layer and has a thickness of 1-3 um.
In another aspect, a method for manufacturing an ultraviolet light emitting diode epitaxial wafer is provided, and the method includes:
providing a substrate;
growing a laser stripping layer on the substrate, wherein the laser stripping layer comprises a first sublayer, a second sublayer and a third sublayer which are sequentially stacked on the substrate, the first sublayer is an InGaN layer, the second sublayer is an Al layer, and the third sublayer is an AlGaN layer;
and sequentially growing a buffer layer, an N-type layer, an active layer and a P-type layer on the laser stripping layer.
Optionally, the growth temperature of three sublayers in the laser peeling layer is 800-1250 ℃, and the growth pressure is 50-200 torr.
Optionally, the manufacturing method further comprises:
and growing an insertion layer between the substrate and the laser stripping layer, wherein the insertion layer is an AlN layer.
The technical scheme provided by the embodiment of the disclosure has the following beneficial effects:
by providing a laser lift-off layer between the substrate and the N-type layer, the laser lift-off layer includes three sublayers. The first sublayer is an InGaN layer, the forbidden band width of the InGaN layer is lower and not more than 0.7ev and far less than 4.34ev, therefore, the first sublayer can absorb excimer laser with the wavelength of 248nm, stripping of the UVC LED substrate is achieved, the color of the first sublayer is relatively deep, laser absorption is facilitated, and laser energy is gathered. The third sublayer is an AlGaN layer, and the forbidden bandwidth of the AlGaN layer is about 3.39ev, less than 4.34ev, and therefore, the third sublayer may also further function to absorb excimer laser light having a wavelength of 248 nm. Since the first sublayer and the third sublayer both contain N, after laser is absorbed by the first sublayer and the third sublayer, N is generated by thermal decomposition2，N2The force generated by the expansion facilitates further separation of the substrate from the epitaxial wafer. Furthermore, the second sublayer is an Al layer, the color of the Al simple substance is gray, and the second sublayer is arranged between the first sublayer and the third sublayer, so that the color of the laser stripping layer is darkened, laser absorption is facilitated, laser energy is gathered, and the stripping of the UVC LED substrate can be further realized.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an ultraviolet light emitting diode epitaxial wafer according to an embodiment of the present disclosure;
fig. 2 is a flowchart of a method for manufacturing an ultraviolet light emitting diode epitaxial wafer according to an embodiment of the present disclosure;
fig. 3 is a flowchart of another method for manufacturing an ultraviolet light emitting diode epitaxial wafer according to an embodiment of the present disclosure.
Detailed Description
To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of an ultraviolet light emitting diode epitaxial wafer according to an embodiment of the present disclosure, and as shown in fig. 1, the ultraviolet light emitting diode epitaxial wafer includes a substrate 1, and a buffer layer 2, an N-type layer 3, an active layer 4, and a P-type layer 5 sequentially stacked on the substrate 1.
The ultraviolet light-emitting diode further comprises a laser stripping layer 6 arranged between the substrate 1 and the buffer layer 2, wherein the laser stripping layer 6 comprises a first sublayer 61, a second sublayer 62 and a third sublayer 63 which are sequentially stacked on the substrate 1, the first sublayer 61 is an InGaN layer, the second sublayer 62 is an Al layer, and the third sublayer 63 is an AlGaN layer.
Embodiments of the present disclosure provide a laser lift-off layer comprising three sublayers by disposing the laser lift-off layer between a substrate and an N-type layer. The first sublayer is an InGaN layer, the forbidden band width of the InGaN layer is lower and not more than 0.7ev and far less than 4.34ev, therefore, the first sublayer can absorb excimer laser with the wavelength of 248nm, stripping of the UVCLED substrate is achieved, the color of the first sublayer is relatively deep, laser absorption is facilitated, and laser energy is gathered. The third sublayer is an AlGaN layer, and the forbidden bandwidth of the AlGaN layer is about 3.39eV and less than 4.34eV, so that the third sublayer can also further play a role in absorbing excimer laser with the wavelength of 248 nm. Since the first sublayer and the third sublayer both contain N, after laser is absorbed by the first sublayer and the third sublayer, N is generated by thermal decomposition2，N2The force generated by the expansion facilitates further separation of the substrate from the epitaxial wafer. Furthermore, the second sublayer is an Al layer, the color of the Al simple substance is gray, and the second sublayer is arranged between the first sublayer and the third sublayer, so that the color of the laser stripping layer is darkened, laser absorption is facilitated, laser energy is gathered, and the stripping of the UVC LED substrate can be further realized.
And because UVC LED is AlGaN base epitaxial layer, consequently, set up the third sublayer that contacts with AlGaN base epitaxial layer in the laser lift-off layer as the AlGaN layer, can make the laser lift-off layer more match with the crystal lattice of AlGaN base epitaxial layer to can guarantee the crystal quality of the AlGaN base epitaxial layer that grows on the laser lift-off layer.
Optionally, the thickness of the third sub-layer 63 is greater than the thickness of the first sub-layer 61, and the thickness of the first sub-layer 61 is greater than the thickness of the second sub-layer 62.
Since the third sub-layer 63 serves as a base layer of the subsequent epitaxial layer, the thickness of the third sub-layer 63 needs to be set to be thicker to prevent the bottom layer defects from extending upward, so that the crystal quality of the epitaxial layer grown thereon can be ensured. The second sub-layer 62 mainly functions to darken the color of the laser peeling layer, and if excessive Al is mixed in the laser peeling layer, too much impurities are mixed in the laser peeling layer, which affects the crystal quality of the epitaxial wafer, so that the thickness of the second sub-layer 62 is set to be the thinnest.
Optionally, the thickness of the first sub-layer 61 is 5 to 50nm, the thickness of the second sub-layer 62 is 1 to 5nm, and the thickness of the third sub-layer 63 is 50to 200 nm.
If the thickness of the first sub-layer 61 is too thin, the absorption effect on laser is poor, and the substrate and the epitaxial wafer cannot be separated; if the thickness of the first sub-layer 61 is too thick, more defects will be generated, thereby affecting the crystal quality of the subsequently grown epitaxial wafer.
If the thickness of the second sub-layer 62 is too thin, the effect of color deepening of the laser peeling layer is poor; if the thickness of the second sub-layer 62 is too thick, the crystal quality of the subsequently grown epitaxial wafer may be affected.
If the thickness of the third sub-layer 63 is too thin, it may not provide a good foundation layer for the subsequent epitaxial layer; if the thickness of the third sub-layer 63 is too thick, cracks may be generated, which is not suitable for the growth of the subsequent epitaxial structure.
Optionally, the third sublayer is AlaGa1-aN layers, a is more than or equal to 0 and less than or equal to 0.33.
By limiting a to 0.33 or less, Al can be ensuredaGa1-aThe N layer has the best effect of absorbing laser light. Laser lift-off layer AlaGa1-aAnd a of N can be equal to 0, namely the N is a GaN material, and can also play a role in absorbing laser to realize the stripping of the substrate and the epitaxial layer.
Optionally, the ultraviolet light emitting diode epitaxial wafer further comprises an insertion layer 7 positioned between the substrate 1 and the laser lift-off layer 6, and the insertion layer 7 is an AlN layer. The laser peeling layer 6 can be matched with the crystal lattice of the substrate better by arranging the insertion layer, and the crystal quality of the grown laser peeling layer is ensured.
Optionally, the thickness of the insertion layer 7 is 10-30 nm.
If the thickness of the insertion layer 7 is too thin, the crystal quality of the laser lift-off layer cannot be improved. If the thickness of the insertion layer 7 is too thick, cracks will be generated, which is not suitable for the growth of the subsequent epitaxial structure.
Optionally, the buffer layer 2 is an AlGaN layer and has a thickness of 1-3 um.
The growth buffer layer 2 is mainly used as a base layer of the substrate and the subsequent epitaxial layer. However, the thickness of the layer should not be too thick because the layer has poor crystalline quality and if it is grown too thick, it will affect the growth of the subsequent epitaxial structure and will absorb light, affecting the external quantum efficiency.
Alternatively, the substrate 1 may be a sapphire substrate.
Optionally, the N-type layer 3 may be a Si-doped AlGaN layer with a thickness of 1000 to 2000nm and a Si doping concentration of 5 × 1018～1*1020cm-3。
Optionally, the active layer 4 includes a plurality of quantum well layers and quantum barrier layers alternately grown in cycles, and the quantum well layers are made of AlxGa1-xN layer, x is more than 0 and less than 1, and the quantum barrier layer is AlyGa1-yN layers, x is more than y and less than 1. The quantum well layer and the quantum barrier layer have different Al component contents, namely, the values of x and y are different, so that different forbidden band widths are provided. Different value combinations of x and y can be selected according to different ultraviolet wavelengths.
The thickness of the quantum well layer is 2-4 nm, and the thickness of the quantum barrier layer is 8-12 nm.
Alternatively, the P-type layer 5 may be an Mg-doped AlGaN layer. The thickness of the P-type layer 5 is 20-30 nm. Mg doping concentration of 1 x 1018～1*1020cm-3。
Optionally, the P-type layer in the embodiment of the present disclosure may also have a composite structure, that is, the P-type layer includes an electron blocking layer and a P-type AlGaN layer, where the electron blocking layer is an AlGaN layer doped with Mg, and the electron blocking layer may be used to block electrons from escaping from the active region to the P-type layer, so that the internal quantum efficiency of the LED may be improved. The P-type AlGaN layer functions as a hole supply layer.
Fig. 2 is a flowchart of a manufacturing method of an ultraviolet light emitting diode epitaxial wafer according to an embodiment of the present disclosure, and as shown in fig. 2, the manufacturing method includes:
step 201, a substrate is provided.
Wherein the substrate is a sapphire substrate.
Step 202, growing a laser lift-off layer on the substrate.
The laser stripping layer comprises a first sublayer, a second sublayer and a third sublayer which are sequentially stacked on the substrate, the first sublayer is an InGaN layer, the second sublayer is an Al layer, and the third sublayer is an AlGaN layer.
Step 203, growing a buffer layer, an N-type layer, an active layer and a P-type layer on the laser stripping layer in sequence.
Wherein, the buffer layer is an AlGaN layer, the N-type layer is an AlGaN layer doped with Si, the thickness is 1000-2000 nm, and the doping concentration of Si is 5 x 1018～1*1020cm-3。
The active layer comprises a plurality of quantum well layers and quantum barrier layers which are alternately grown in a period, wherein the quantum well layers are made of AlxGa1-xN layer, x is more than 0 and less than 1, and the quantum barrier layer is AlyGa1-yN layers, x is more than y and less than 1. The quantum well layer and the quantum barrier layer have different Al component contents, namely, the values of x and y are different, so that different forbidden band widths are provided. Different value combinations of x and y can be selected according to different ultraviolet wavelengths. The thickness of the quantum well layer is 2-4 nm, and the thickness of the quantum barrier layer is 8-12 nm.
The P-type layer can be an AlGaN layer doped with Mg with the doping concentration of 1 x 1018～1*1020cm-3. The thickness of the P-type layer is 20-30 nm.
Embodiments of the present disclosure provide a laser lift-off layer comprising three sublayers by disposing the laser lift-off layer between a substrate and an N-type layer. The first sublayer is an InGaN layer, the forbidden band width of the InGaN layer is lower and not more than 0.7ev and far less than 4.34ev, therefore, the first sublayer can absorb excimer laser with the wavelength of 248nm, stripping of the UVCLED substrate is achieved, the color of the first sublayer is relatively deep, laser absorption is facilitated, and laser energy is gathered. The third sublayer is an AlGaN layer, and the forbidden bandwidth of the AlGaN layer is about 3.39eV and less than 4.34eV, so that the third sublayer can also further play a role in absorbing excimer laser with the wavelength of 248 nm. Since the first sublayer and the third sublayer both contain N, after laser is absorbed by the first sublayer and the third sublayer, N is generated by thermal decomposition2，N2The force generated by the expansion facilitates further separation of the substrate from the epitaxial wafer. Furthermore, the second sublayer is an Al layer, the color of the Al simple substance is gray, and the second sublayer is arranged between the first sublayer and the third sublayer, so that the color of the laser stripping layer is darkened, laser absorption is facilitated, laser energy is gathered, and the stripping of the UVC LED substrate can be further realized.
Fig. 3 is a flowchart of another manufacturing method of an ultraviolet light emitting diode epitaxial wafer according to an embodiment of the present disclosure, and as shown in fig. 3, the manufacturing method includes:
step 301, a substrate is provided.
Wherein the substrate is sapphire.
In this embodiment, a Veeco K465i or C4or RB MOCVD (Metal organic chemical Vapor Deposition) apparatus is used to realize the manufacturing method of the epitaxial wafer. By using high-purity H2(Hydrogen) or high purity N2(Nitrogen) or high purity H2And high purity N2The mixed gas of (2) is used as a carrier gas, high-purity NH3As the N source, trimethyl gallium (TMGa) and triethyl gallium (TEGa) as gallium sources, trimethyl indium (TMIn) as indium sources, Silane (SiH)4) As N-type dopant, trimethylaluminum (TMAl) as aluminum source, magnesium diclomentate (CP)2Mg) as a P-type dopant. The pressure in the reaction chamber is 100to 600 torr.
Step 302, growing an interposer on a substrate.
Wherein, the insertion layer is an AlN layer with the thickness of 10-30 nm.
In the embodiment of the disclosure, the substrate may be placed in an MOCVD reaction chamber, and TMAl and NH may be introduced into the reaction chamber3And preparing the AlN thin film by a chemical vapor deposition method.
Illustratively, the temperature in the reaction chamber is controlled to be 800-1000 ℃, the pressure is controlled to be 50-100 torr, and an AlN thin film with the thickness of 15nm is deposited on the sapphire substrate.
Alternatively, the insertion layer can also be produced in a PVD (Physical vapor Deposition) reaction chamber.
Illustratively, the substrate is placed in a PVD reaction chamber and the reaction chamber is ventedInto N2And Ar, bombarding the Al target material by using Ar plasma formed under an electric field, and reacting the sputtered Al atoms with ionized N atoms to form the AlN thin film.
Step 303, growing a laser lift-off layer on the insertion layer.
The laser stripping layer comprises a first sublayer, a second sublayer and a third sublayer which are sequentially stacked on the substrate, the first sublayer is an InGaN layer, the second sublayer is an Al layer, and the third sublayer is an AlGaN layer.
Optionally, the thickness of the third sub-layer is greater than the thickness of the first sub-layer, which is greater than the thickness of the second sub-layer.
Since the third sub-layer is used as a base layer of the subsequent epitaxial layer, the thickness of the third sub-layer needs to be set to be thicker to prevent the bottom layer defects from extending upwards, so that the crystal quality of the epitaxial layer grown on the third sub-layer can be ensured. The second sub-layer mainly functions to deepen the color of the laser stripping layer, if excessive Al is mixed in the laser stripping layer, too many impurities are mixed in the laser stripping layer, and the crystal quality of the epitaxial wafer is affected, so that the thickness of the second sub-layer is set to be the thinnest.
Optionally, the thickness of the first sub-layer is 5-50 nm, the thickness of the second sub-layer is 1-5 nm, and the thickness of the third sub-layer is 50-200 nm.
If the thickness of the first sublayer is too thin, the absorption effect on laser is poor, and the separation of the substrate and the epitaxial wafer cannot be realized; if the thickness of the first sublayer is too thick, more defects are generated, and the crystal quality of the epitaxial wafer grown subsequently is affected.
If the thickness of the second sublayer is too thin, the effect of deepening the color of the laser stripping layer is poor; if the thickness of the second sub-layer is too thick, the crystal quality of the subsequently grown epitaxial wafer is affected.
If the thickness of the third sub-layer is too thin, a good foundation layer cannot be provided for the subsequent epitaxial layer; if the thickness of the third sub-layer is too thick, cracks can be generated, and the growth of a subsequent epitaxial structure is not suitable.
Optionally, the third sublayer is AlaGa1-aN layer，0≤a≤0.33。
By limiting a to 0.33 or less, Al can be ensuredaGa1-aThe N layer has the best effect of absorbing laser light. Laser lift-off layer AlaGa1-aAnd a of N can be equal to 0, namely the N is a GaN material, and can also play a role in absorbing laser to realize the stripping of the substrate and the epitaxial layer.
Optionally, the growth temperature of three sublayers in the laser peeling layer is 800-1250 ℃, and the growth pressure is 50-200 torr, so that the actual growth control is facilitated.
Alternatively, the growth temperatures of the three sublayers in the laser lift-off layer may be the same or different, for example, the growth temperature of the first sublayer is higher than that of the second sublayer, and the growth temperature of the second sublayer is higher than that of the third sublayer.
Illustratively, three sublayers in the laser lift-off layer are grown by the MOCVD method.
Step 304, a buffer layer is grown on the laser lift-off layer.
Wherein, the buffer layer is an AlGaN layer.
The growth buffer layer is mainly used as a base layer of the substrate and the subsequent epitaxial layer. However, the thickness of the layer should not be too thick because the layer has poor crystalline quality and if it is grown too thick, it will affect the growth of the subsequent epitaxial structure and will absorb light, affecting the external quantum efficiency.
Illustratively, the temperature in the reaction chamber is controlled to be 1000-1250 ℃, the pressure is controlled to be 50-100 torr, and an AlGaN layer film with the thickness of 1.5um is grown on the laser stripping layer.
Step 305, an N-type layer is grown on the buffer layer.
Wherein the N-type layer is an AlGaN layer doped with Si, and the doping concentration of the Si is 5 x 1018～1*1020cm-3。
Illustratively, the temperature in the reaction chamber is controlled to be 1200-1300 ℃, the pressure is controlled to be 50-100 torr, and an N-type layer with the thickness of 1000-2000 nm is grown on the undoped AlGaN layer.
Step 306, an active layer is grown on the N-type layer.
Wherein the active layer comprises a plurality of layersAnd the quantum well layer and the quantum barrier layer are alternately grown. The quantum well layer is AlxGa1- xN layer, x is more than 0 and less than 1, and the quantum barrier layer is AlyGa1-yN layers, x is more than y and less than 1.
Optionally, the active layer comprises 5-12 quantum well layers and quantum barrier layers which are alternately grown in cycles.
Optionally, the thickness of the quantum well layer is 2-4 nm, and the thickness of the quantum barrier layer is 8-12 nm.
Illustratively, step 306 may include:
the active layer was grown by controlling the temperature in the reaction chamber to 1060 ℃ and the pressure to 250 torr.
Step 307, a P-type layer is grown on the active layer.
Wherein the P-type layer is an AlGaN layer doped with Mg, and the doping concentration of Mg is 1 x 1018～1*1020cm-3。
Illustratively, the temperature in the reaction chamber is controlled to be 1200-1250 ℃, the pressure is controlled to be 50-100 torr, and a P-type layer with the thickness of 20-30 nm is grown.
Or, the P-type layer comprises an electron blocking layer and a P-type AlGaN layer, wherein the electron blocking layer is an AlGaN layer doped with Mg, and the electron blocking layer can be used for blocking electrons from escaping from the active region to the P-type layer, so that the internal quantum efficiency of the LED can be improved. The P-type AlGaN layer functions as a hole supply layer.
Step 307 may further comprise:
controlling the temperature in the reaction cavity to be 1000-1250 ℃, the pressure to be 50-200 torr, and growing the electron blocking layer with the thickness of 50-500 nm.
After the steps are completed, the temperature of the reaction chamber is reduced to 650-850 ℃, annealing treatment is carried out for 5-15 min in a nitrogen atmosphere, then the temperature is gradually reduced to the room temperature, and the epitaxial growth of the ultraviolet light emitting diode is finished.
Embodiments of the present disclosure provide a laser lift-off layer comprising three sublayers by disposing the laser lift-off layer between a substrate and an N-type layer. The first sublayer is an InGaN layer, the forbidden band width of the InGaN layer is lower and not more than 0.7ev and far less than 4.34ev, therefore, the first sublayer can absorb excimer laser with the wavelength of 248nm, and the real effect is realizedThe UVCLED substrate is stripped, and the first sub-layer is relatively dark in color, so that laser can be absorbed more favorably, and laser energy is gathered. The third sublayer is an AlGaN layer, and the forbidden bandwidth of the AlGaN layer is about 3.39eV and less than 4.34eV, so that the third sublayer can also further play a role in absorbing excimer laser with the wavelength of 248 nm. Since the first sublayer and the third sublayer both contain N, after laser is absorbed by the first sublayer and the third sublayer, N is generated by thermal decomposition2，N2The force generated by the expansion facilitates further separation of the substrate from the epitaxial wafer. Furthermore, the second sublayer is an Al layer, the color of the Al simple substance is gray, and the second sublayer is arranged between the first sublayer and the third sublayer, so that the color of the laser stripping layer is darkened, laser absorption is facilitated, laser energy is gathered, and the stripping of the UVC LED substrate can be further realized.
The above description is intended to be exemplary only and not to limit the present disclosure, and any modification, equivalent replacement, or improvement made without departing from the spirit and scope of the present disclosure is to be considered as the same as the present disclosure.

Claims (10)

1. An ultraviolet light-emitting diode epitaxial wafer comprises a substrate, and a buffer layer, an N-type layer, an active layer and a P-type layer which are sequentially laminated on the substrate,
the ultraviolet light-emitting diode further comprises a laser stripping layer arranged between the substrate and the buffer layer, wherein the laser stripping layer comprises a first sublayer, a second sublayer and a third sublayer which are sequentially stacked on the substrate, the first sublayer is an InGaN layer, the second sublayer is an Al layer, and the third sublayer is an AlGaN layer.
2. The ultraviolet light emitting diode epitaxial wafer of claim 1, wherein the thickness of the third sub-layer is greater than the thickness of the first sub-layer, and the thickness of the first sub-layer is greater than the thickness of the second sub-layer.
3. The ultraviolet light emitting diode epitaxial wafer as claimed in claim 2, wherein the thickness of the first sub-layer is 5-50 nm, the thickness of the second sub-layer is 1-5 nm, and the thickness of the third sub-layer is 50-200 nm.
4. The ultraviolet light emitting diode epitaxial wafer as claimed in claim 3, wherein the third sub-layer is AlaGa1- aN layers, a is more than or equal to 0 and less than or equal to 0.33.
5. The uv led epitaxial wafer as claimed in claim 1, further comprising an insertion layer between the substrate and the laser lift-off layer, wherein the insertion layer is an AlN layer.
6. The ultraviolet light emitting diode epitaxial wafer as claimed in claim 5, wherein the thickness of the insertion layer is 10-30 nm.
7. The ultraviolet light-emitting diode epitaxial wafer as claimed in claim 5, wherein the buffer layer is an AlGaN layer and has a thickness of 1-3 um.
8. A manufacturing method of an ultraviolet light emitting diode epitaxial wafer is characterized by comprising the following steps:
providing a substrate;
growing a laser stripping layer on the substrate, wherein the laser stripping layer comprises a first sublayer, a second sublayer and a third sublayer which are sequentially stacked on the substrate, the first sublayer is an InGaN layer, the second sublayer is an Al layer, and the third sublayer is an AlGaN layer;
and sequentially growing a buffer layer, an N-type layer, an active layer and a P-type layer on the laser stripping layer.
9. The method of claim 8, wherein the growth temperature and the growth pressure of each of the three sublayers of the laser lift-off layer are 800-1250 ℃ and 50-200 torr respectively.
10. The manufacturing method according to claim 8, characterized by further comprising:
and growing an insertion layer between the substrate and the laser stripping layer, wherein the insertion layer is an AlN layer.
CN202110294170.5A 2021-03-19 2021-03-19 Ultraviolet light-emitting diode epitaxial wafer and manufacturing method thereof Withdrawn CN113224211A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114855273A (en) * 2022-04-20 2022-08-05 江西兆驰半导体有限公司 Epitaxial wafer preparation method, epitaxial wafer and light emitting diode

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114855273A (en) * 2022-04-20 2022-08-05 江西兆驰半导体有限公司 Epitaxial wafer preparation method, epitaxial wafer and light emitting diode
CN114855273B (en) * 2022-04-20 2023-11-21 江西兆驰半导体有限公司 Epitaxial wafer preparation method, epitaxial wafer and light-emitting diode

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Application publication date: 20210806