CN116759499A - Tunneling junction and preparation method thereof, double-junction infrared LED epitaxial structure and preparation method thereof - Google Patents

Tunneling junction and preparation method thereof, double-junction infrared LED epitaxial structure and preparation method thereof Download PDF

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CN116759499A
CN116759499A CN202310676306.8A CN202310676306A CN116759499A CN 116759499 A CN116759499 A CN 116759499A CN 202310676306 A CN202310676306 A CN 202310676306A CN 116759499 A CN116759499 A CN 116759499A
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layer
doped
component
graded
confinement
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廖寅生
李森林
毕京锋
王亚宏
薛龙
赖玉财
董雪振
丘金金
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Xiamen Silan Advanced Compound Semiconductor Co Ltd
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Xiamen Silan Advanced Compound Semiconductor 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/15—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission
    • 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
    • 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
    • H01L33/025—Physical imperfections, e.g. particular concentration or distribution of impurities

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Abstract

The invention provides a tunneling junction and a preparation method thereof, a double-junction infrared LED epitaxial structure and a preparation method thereof, wherein the tunneling junction sequentially comprises a first doping layer, a graded doping layer and a second doping layer from bottom to top, the first doping layer and the graded doping layer are doped with dopants of the same type, the first doping layer and the second doping layer are doped with dopants of different types, the graded doping layer comprises a P component and an As component, the graded doping layer is a graded layer of the P component and the As component, the change trend of the P component and the As component is opposite, through the gradual change of the As and the P in the graded doping layer from bottom to top, the effective switching of the As and the P is realized, the interface quality and the crystal growth quality are effectively improved, the series resistance is reduced, the working voltage is reduced, and the photoelectric conversion efficiency is improved.

Description

Tunneling junction and preparation method thereof, double-junction infrared LED epitaxial structure and preparation method thereof
Technical Field
The invention relates to the technical field of semiconductors, in particular to a tunneling junction and a preparation method thereof, a double-junction infrared LED epitaxial structure and a preparation method thereof.
Background
A light emitting diode (LED, light Emitting Diode) is a semiconductor solid state light emitting device, which has advantages of simple structure, light weight, no pollution, etc., and has been widely used in various fields of digital, display, illumination, plant engineering, etc., and is called an environment-friendly, energy-saving green illumination light source, which has a huge business opportunity. The infrared light emitting diode is used as an important light emitting diode and is widely applied to the fields of security monitoring, remote control, vehicle sensing, closed-circuit television and the like, but the current infrared light emitting diode has poor night vision effect.
The conventional infrared LED epitaxial structure uses an AlGaAs/AlGaAs stacked structure for tunneling, but the bandgap of AlGaAs is smaller increases the absorption of invisible light, decreases the brightness of the device, increases the series resistance, increases the voltage, and because the bandgap of GaInP is wider than that of AlGaAs, alGaAs/GaInP stacked structure (in which AlGaAs is heavily doped P-type AlGaAs and GaInP is heavily doped N-type GaInP) is generally used instead of AlGaAs/AlGaAs stacked structure, the above problems can be effectively improved, but if GaInP is grown directly on AlGaAs, new problems are caused, such as: the crystal quality of the As\P interface is low; lattice mismatch between heavily doped AlGaAs and heavily doped GaInP results in crystal defects.
Disclosure of Invention
One of the objectives of the present invention is to provide a tunneling junction and a method for manufacturing the same, which can reduce series resistance and operating voltage, thereby improving photoelectric conversion efficiency.
The invention further aims to provide a tunneling junction and a preparation method thereof, which can reduce the absorption of the tunneling junction to invisible light, improve the brightness of an infrared LED and reduce the series resistance and the working voltage.
The invention further aims to provide a double-junction infrared LED epitaxial structure and a preparation method thereof, which can enhance the night vision effect of the infrared LED, thereby being beneficial to the application of the infrared LED in security monitoring.
In order to solve the problems, the invention provides a tunneling junction, which sequentially comprises a first doping layer, a graded doping layer and a second doping layer from bottom to top, wherein the first doping layer and the graded doping layer are doped with dopants of the same type, the first doping layer and the second doping layer are doped with dopants of different types, the graded doping layer comprises a P component and an As component, the graded doping layer is a graded layer of the P component and the As component, and the change trend of the P component and the change trend of the As component are opposite.
Optionally, the P component gradually increases from bottom to top, and the As component gradually decreases from bottom to top.
Further, the material of the first doped layer is Al x1 Ga 1-x1 As, wherein the value range of x1 is 0.1-0.3;
the material of the graded doped layer is Al x2 Ga 1-x2 As y P 1-y Wherein, the value range of x2 is 0.1-0.3, and the value range of y is 0.8-1; and
the material of the second doped layer is GaInSb z P 1-z Wherein, the value range of z is 0 to 0.02.
Further, the material of the graded doped layer contains an Sb component, and the Sb component is more than 0 and less than or equal to 2%.
Optionally, the first doped layer and the graded doped layer are doped with P-type dopants, and the second doped layer is doped with N-type dopants.
Optionally, the thickness of the first doped layer is 10 nm-30 nm, the thickness of the graded doped layer is 2 nm-10 nm, and the thickness of the second doped layer is 2 nm-20 nm.
In another aspect, the present invention provides a method for fabricating a tunneling junction, comprising:
forming a first doped layer;
forming a graded doping layer on the first doping layer, wherein the graded doping layer comprises a P component and an As component, the graded doping layer is a graded layer of the P component and the As component, and the change trend of the P component and the change trend of the As component are opposite; and
and forming a second doped layer on the graded doped layer, wherein the first doped layer and the graded doped layer are doped with the same type of dopant, and the first doped layer and the second doped layer are doped with different types of dopant.
Optionally, the P component gradually increases from bottom to top, and the As component gradually decreases from bottom to top.
Further, the material of the first doped layer is Al x1 Ga 1-x1 As, wherein the value range of x1 is 0.1-0.3;
the material of the graded doped layer is Al x2 Ga 1-x2 As y P 1-y Wherein, the value range of x2 is 0.1-0.3, and the value range of y is 0.8-1; and
the material of the second doped layer is GaInSb z P 1-z Wherein, the value range of z is 0 to 0.02.
Further, the material of the graded doped layer contains an Sb component, and the Sb component is more than 0 and less than or equal to 2%.
Optionally, the first doped layer and the graded doped layer are doped with P-type dopants, and the second doped layer is doped with N-type dopants.
Optionally, the thickness of the first doped layer is 10 nm-30 nm, the thickness of the graded doped layer is 2 nm-10 nm, and the thickness of the second doped layer is 2 nm-20 nm.
In still another aspect, the present invention provides a dual-junction infrared LED epitaxial structure, including the tunnel junction, and further including a first LED structure and a second LED structure stacked on a substrate from bottom to top, where the tunnel junction is located between the first LED structure and the second LED structure.
Optionally, the radiation wavelength of the first LED structure is 740nm to 760nm, and the radiation wavelength of the second LED structure is 840nm to 870nm.
Optionally, the first LED structure includes a first active layer, the first active layer is a multiple quantum well structure formed by alternately growing a first well layer and a first barrier layer with a preset period number, and the material of the first well layer is Al a Ga 1-a As, wherein the value range of a is 0.1-0.2; the material of the first barrier layer is Al b Ga 1-b As, wherein, the value range of b is 0.35-0.5.
Further, the first LED structure further includes a first ohmic contact layer, a first window layer, a first limiting layer and a second limiting layer, where the first ohmic contact layer, the first window layer, the first limiting layer, the first active layer and the second limiting layer are sequentially disposed from bottom to top, N-type dopants are doped in the first ohmic contact layer, the first window layer and the first limiting layer, and P-type dopants are doped in the second limiting layer.
Optionally, the second LED structure includes a second active layer, the second active layer is a multiple quantum well structure In which a second well layer and a second barrier layer alternately grow, and the material of the second well layer is In c Ga 1-c As, wherein the value range of c is 0.1-0.15; the material of the second barrier layer is Al d Ga 1-d As, wherein d has a value ranging from 0.15 to 0.4.
Further, the second LED structure further includes a third limiting layer, a fourth limiting layer, a second window layer and a second ohmic contact layer, where the third limiting layer, the second active layer, the fourth limiting layer, the second window layer and the second ohmic contact layer are sequentially arranged from bottom to top, N-type dopants are doped in the third limiting layer, and P-type dopants are doped in the fourth limiting layer, the second window layer and the second ohmic contact layer.
In yet another aspect, the present invention provides a method for preparing a dual junction infrared LED epitaxial structure, comprising the steps of:
providing a substrate;
sequentially forming a first LED structure, a tunneling junction and a second LED structure on the substrate from bottom to top;
the preparation method of the tunneling junction is adopted to prepare the tunneling junction.
Optionally, the radiation wavelength of the first LED structure is 740nm to 760nm, and the radiation wavelength of the second LED structure is 840nm to 870nm.
Optionally, the first LED structure includes a first active layer, the first active layer is a multiple quantum well structure formed by alternately growing a first well layer and a first barrier layer with a preset period number, and the material of the first well layer is Al a Ga 1-a As, wherein the value range of a is 0.1-0.2; the material of the first barrier layer is Al b Ga 1-b As, wherein, the value range of b is 0.35-0.5.
Further, the first LED structure further includes a first ohmic contact layer, a first window layer, a first limiting layer and a second limiting layer, where the first ohmic contact layer, the first window layer, the first limiting layer, the first active layer and the second limiting layer are sequentially disposed from bottom to top, N-type dopants are doped in the first ohmic contact layer, the first window layer and the first limiting layer, and P-type dopants are doped in the second limiting layer.
Optionally, the second LED structure includes a second active layer, the second active layer is a multiple quantum well structure In which a second well layer and a second barrier layer alternately grow, and the material of the second well layer is In c Ga 1-c As, wherein the value range of c is 0.1-0.15; the material of the second barrier layer is Al d Ga 1-d As, wherein d has a value ranging from 0.15 to 0.4.
Further, the second LED structure further includes a third limiting layer, a fourth limiting layer, a second window layer and a second ohmic contact layer, where the third limiting layer, the second active layer, the fourth limiting layer, the second window layer and the second ohmic contact layer are sequentially arranged from bottom to top, N-type dopants are doped in the third limiting layer, and P-type dopants are doped in the fourth limiting layer, the second window layer and the second ohmic contact layer.
Compared with the prior art, the invention has the following beneficial effects:
1. through the gradual change of As and P in the gradual change doped layer from bottom to top, the effective switching of As and P is realized, the interface quality and the crystal growth quality are effectively improved, the series resistance is reduced, the working voltage is reduced, and the photoelectric conversion efficiency is improved.
2. Through the first doped layer (Al x1 Ga 1-x1 As) and a second doped layer (GaInSb z P 1-z ) Interposed graded doped layer (Al x2 Ga 1-x2 As y P 1-y ) The interface quality and the crystal growth quality are effectively improved, the series resistance is reduced, and the working voltage is reduced. In addition, a second doped layer (GaInSb z P 1-z ) The quality of the crystal is improved, the tunneling peak current and the tunneling characteristic are improved, and the tunneling voltage is reduced.
3. The radiation wavelength of the first LED structure is 740-760 nm, the radiation wavelength of the second LED structure is 840-870 nm, namely, the first LED structure and the second LED structure with two different radiation wavelengths are adopted to form a double-junction infrared LED epitaxial structure, so that light supplementing is carried out on the conventional 840-870 nm wave band through the near infrared rays with the wave band of 740-760 nm, the night vision effect of the infrared LED is enhanced, and the application of the infrared LED in security monitoring is facilitated.
Drawings
Fig. 1 is a schematic structural diagram of a dual-junction infrared LED epitaxial structure according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a method for fabricating a tunneling junction according to an embodiment of the present invention;
fig. 3 is a flowchart of a method for manufacturing a dual-junction infrared LED epitaxial structure according to an embodiment of the present invention.
Reference numerals illustrate:
100-a substrate; 110-a buffer layer; 120-an etch stop layer; 200-a first LED structure; 210-a first ohmic contact layer; 220-a first window layer; 230-a first confinement layer; 240-a first active layer; 250-a second confinement layer; 300-tunneling junction; 310-a first doped layer; 320-a graded doped layer; 330-a second doped layer; 400-a second LED structure; 410-a third confinement layer; 420-a second active layer; 430-a fourth confinement layer; 440-a second window layer; 450-second ohmic contact layer.
Detailed Description
The tunneling junction, the preparation method, the double-junction infrared LED epitaxial structure and the preparation method thereof are further described in detail below. The present invention will be described in more detail below with reference to the attached drawings, in which preferred embodiments of the present invention are shown, it being understood that one skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Accordingly, the following description is to be construed as broadly known to those skilled in the art and not as limiting the invention.
In the interest of clarity, not all features of an actual implementation are described. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It should be appreciated that in the development of any such actual embodiment, numerous implementation details must be made to achieve the developer's specific goals, such as compliance with system-related or business-related constraints, which will vary from one implementation to another. In addition, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art.
In order to make the objects and features of the present invention more comprehensible, embodiments accompanied with figures are described in detail below. It is noted that the drawings are in a very simplified form and utilize non-precise ratios, and are intended to facilitate a convenient, clear, description of the embodiments of the invention.
Before the embodiments according to the present invention are described, the following will be described in advance. First, in the present specification, when only "GaInP" is labeled, the chemical composition ratio of the sum of Ga and In to P is 1:1, a random compound In which the ratio of Ga to In is not fixed; only labeled "AlInP" indicates that the chemical composition ratio of the sum of Al and In to P is 1:1, the ratio of Al to In is not fixed. In addition, the direction from the substrate to the second ohmic contact layer in fig. 1 is defined to be from bottom to top.
Fig. 1 is a schematic structural diagram of a dual-junction infrared LED epitaxial structure according to the present embodiment. As shown in fig. 1, the present embodiment provides a tunneling junction 300, where the tunneling junction 300 includes, from bottom to top, a first doped layer 310, a graded doped layer 320, and a second doped layer 330. The first doped layer 310 and the graded doped layer 320 are doped with the same type of dopant, the first doped layer 310 and the second doped layer 330 are doped with different types of dopant, the graded doped layer 320 contains a P component and an As component, the graded doped layer 320 is a graded layer of the P component and the As component, and the change trend of the P component and the As component is opposite.
The first doping layer 310 is doped with a first type dopant, for example, a P-type dopant, and may be at least one of carbon (C), magnesium (Mg), and zinc (Zn), but is not limited thereto. The doping concentration of the first type dopant doped in the first doping layer 310 is 1E19 cm -3 ～1E20 cm -3 Preferably, the doping concentration of the first type dopant doped in the first doping layer 310 is 2E19 cm -3 . The material of the first doped layer 310 may be Al x1 Ga 1-x1 As, wherein, the value range of x1 is 0.1-0.3. The thickness of the first doping layer 310 may be 10nm to 30nm, and preferably, the thickness of the first doping layer 310 is 10nm.
The graded doped layer 320 is doped with a first type dopant, such as a P-type dopant, and may be at least one of carbon (C), magnesium (Mg), and zinc (Zn), but is not limited thereto. The doping concentration of the first type dopant doped in the graded doped layer 320 may be 1e19 cm -3 ～1E20 cm -3 Preferably, the doping concentration of the first type dopant doped in the graded doped layer 320 is 2E19 cm -3 . The graded doped layer 320 may be made of Al x2 Ga 1-x2 As y P 1-y Wherein, the value range of x2 is 0.1-0.3, the value range of y is 0.8-1, and the value range of y is preferably 0.9-1, so as to avoid the problems of large lattice mismatch and more defects caused by too small value of yThe P (phosphorus) component in the graded doped layer 320 gradually increases from bottom to top (from the first doped layer 310 to the second doped layer 330), i.e., the value of y gradually decreases from bottom to top, so that the As component in the graded doped layer 320 gradually decreases from 1 to y linearly, i.e., the P component gradually increases from bottom to top, and at the same time, the As component gradually decreases from bottom to top. The thickness of the graded doped layer 320 may be 2nm to 10nm, and preferably, the thickness of the graded doped layer 320 is 5nm. Compared with the method adopting the InGaAsP material as the graded doped layer 320, in is easy to be separated out by direct growth, and interface defects are fewer by the graded growth of the P component In the graded doped layer 320 through the transition of the graded doped layer 320; meanwhile, the bandgap of the graded doped layer 320 is wider than that of the InGaAsP material, and the graded doped layer has less light absorption, so that the brightness of the infrared light emitting diode is higher.
Optionally, al of the graded doped layer 320 x2 Ga 1-x2 As y P 1-y The graded doped layer 320 further contains an Sb component, so that the effect of the tunneling characteristic of the graded doped layer 320 is better, that is, the Sb component can be used as a surfactant to improve the crystal quality, improve the tunneling peak current, reduce the potential barrier, improve the tunneling characteristic, reduce the tunneling voltage, and further, the Sb component is more than 0 and less than or equal to 2%.
The second doping layer 330 is doped with a second type dopant, for example, an N-type dopant, and may be at least one of silicon (Si) and tellurium (Te), but is not limited thereto. The doping concentration of the second type dopant doped in the second doping layer 330 may be 1e19 cm -3 ～5E19 cm -3 Preferably, the doping concentration of the second type dopant doped in the second doping layer 330 is 1E19 cm -3 . The material of the second doped layer 330 may be GaInSb z P 1-z Wherein, the value of z ranges from 0 to 0.02, preferably, the value of z ranges from more than 0 and less than or equal to 0.02, and the antimony (Sb) in the second doped layer 330 has the function of surfactant, thereby reducing the activation energy, improving the mobility of atoms, reducing defects and improving the crystal quality, thereby reducing non-radiative recombination and improving the tunneling peakA current; and the band gap of the second doped layer 330 is smaller than that in the prior art, so that the potential barrier can be reduced, the tunneling characteristic can be improved, and the tunneling voltage can be reduced. The thickness of the second doping layer 330 may be 2nm to 20nm, and preferably, the thickness of the second doping layer 330 is 5nm.
And a graded doped layer 320 interposed between the first doped layer 310 and the second doped layer 330, wherein As and P in the graded doped layer 320 are graded from bottom to top, so that effective switching between As and P is realized, interface quality and crystal growth quality are effectively improved, series resistance is reduced, and working voltage is reduced, thereby improving photoelectric conversion efficiency.
Fig. 2 is a flow chart of a method for manufacturing a tunneling junction according to the present embodiment. As shown in fig. 2, with continued reference to fig. 1, the present embodiment further provides a method for manufacturing a tunneling junction 300, which includes the following steps:
step S11, forming a first doped layer 310;
step S12, forming a graded doped layer 320 on the first doped layer 310, where the graded doped layer 320 includes a P component and an As component, and the graded doped layer 320 is a graded layer of the P component and the As component, and the change trend of the P component and the As component is opposite; and
in step S13, a second doped layer 330 is formed on the graded doped layer 320, where the doping types of the first doped layer 310 and the graded doped layer 320 are the same, and the doping type of the second doped layer 330 is opposite to that of the first doped layer 310.
In step S12, the P component and the As component are graded from the first doped layer 310 toward the second doped layer 330, and the material of the graded doped layer 320 may be Al x2 Ga 1-x2 As y P 1-y Wherein, the value range of x2 is 0.1-0.3, the value range of y is 0.8-1, and the value range of y is preferably 0.9-1. The P component gradually increases from bottom to top while the As component gradually decreases from bottom to top, so that the As component in the graded doped layer 320 gradually decreases linearly from 1 to y, that is, the P component gradually increases from bottom to top while the As component gradually decreases from bottom to topGradually decreasing.
Optionally, the material of the graded doped layer contains an Sb component, and the Sb component is greater than 0 and less than or equal to 2%.
Wherein the material of the first doped layer is Al x1 Ga 1-x1 As, wherein the value range of x1 is 0.1-0.3; the material of the second doped layer is GaInSb z P 1-z Wherein, the value of z ranges from 0 to 0.02, and preferably, the value of z ranges from more than 0 to less than or equal to 0.02. The thickness of the first doping layer is 10-30 nm, the thickness of the gradual change doping layer is 2-10 nm, and the thickness of the second doping layer is 2-20 nm.
In step S13, the first doped layer 310 and the graded doped layer 320 are doped with a first type dopant (i.e., P-type dopant), and the second doped layer 330 is doped with a second type dopant (i.e., N-type dopant).
With continued reference to fig. 1, the present embodiment provides a dual-junction infrared LED epitaxial structure, which includes a first LED structure 200, a tunnel junction 300, and a second LED structure 400 stacked on a substrate 100 sequentially from bottom to top. The radiation wavelength (i.e., the radiation peak wavelength) of the first LED structure 200 is 740nm to 760nm, and the radiation wavelength (i.e., the radiation peak wavelength) of the second LED structure 400 is 840nm to 870nm, so that two LED structures with different wavelengths are adopted, that is, the first LED structure 200 supplements light for the infrared LED (i.e., the second LED structure 400) with the conventional radiation wavelength of 840nm to 870nm, thereby enhancing the night vision effect of the infrared LED epitaxial structure and being beneficial to the application of the infrared LED in security monitoring.
The substrate 100 is doped with an n-type dopant, for example, and the substrate 100 includes, but is not limited to, a GaAs (gallium arsenide) substrate 100 and a Si substrate 100, preferably the substrate 100 is a GaAs substrate 100.
A buffer layer 110 and an etch stop layer 120 are further formed between the substrate 100 and the first LED structure 200, the buffer layer 110 being located on the substrate 100, the etch stop layer 120 being located on the buffer layer 110.
The buffer layer 110 can minimize defects and dislocations that occur in the dual-junction infrared LED epitaxial structure due to surface defects of the substrate 100 and provide good surface quality for the next subsequent process (i.e., forming the etch stop layer 120). The buffer layer 110 is doped with a second type dopant, for example, an N type dopant, and may be at least one of silicon (Si) and tellurium (Te), but is not limited thereto. Further, the second type dopant is preferably Si. The material of the buffer layer 110 includes, but is not limited to, gaAs. The thickness of the buffer layer 110 may be 100nm to 300nm, and preferably, the thickness of the buffer layer 110 is 150nm.
The etch stop layer 120 is doped with a second type dopant, for example, an N type dopant, and may be at least one of silicon (Si) and tellurium (Te), but is not limited thereto. Further, the second type dopant is preferably Si. The material of the etch stop layer 120 includes, but is not limited to, gaAs, the thickness of the etch stop layer 120 may be 100nm to 300nm, preferably the thickness of the etch stop layer 120 is 150nm, and the etch stop layer 120 is a stop layer for removing the substrate 100 in cooperation with a reverse polarity chip process.
The first LED structure 200 includes, in order from bottom to top, a first semiconductor layer, a first active layer 240, and a second semiconductor layer, where the first semiconductor layer is located on the etch stop layer 120. The first semiconductor layer includes, from bottom to top, a first ohmic contact layer 210, a first window layer 220, and a first confinement layer 230. The radiation wavelength of the first active layer 240 may be 740nm to 760nm. The second semiconductor layer includes a second confinement layer 250.
The second type dopant, for example, an N type dopant, is doped in the first ohmic contact layer 210, and may be at least one of silicon (Si) and tellurium (Te), but is not limited thereto. Further, the second type dopant is preferably Si. The thickness of the first ohmic contact layer 210 may be 20nm to 150nm, and preferably, the thickness of the first ohmic contact layer 210 is 50nm. The material of the first ohmic contact layer 210 includes, but is not limited to, inGaAs and GaAs, and preferably, the material of the first ohmic contact layer 210 is GaAs.
The first window layer 220 is doped with a second type dopant, such as N-type dopant, which may be silicon (Si), tellurium (Te)At least one, but not limited thereto. Further, the second type dopant is preferably Si, and the doping concentration of the second type dopant in the first window layer 220 is 1E18cm -3 ～2E18cm -3 . The thickness of the first window layer 220 may be 1.5 μm to 8 μm, and preferably, the thickness of the first window layer 220 is 3 μm. The material of the first window layer 220 may be AlGaInP.
The first confinement layer 230 is doped with a second type dopant, such as an N-type dopant, and may be at least one of silicon (Si) and tellurium (Te), but is not limited thereto. Further, the second type dopant is preferably Si, and the doping concentration of the second type dopant in the first confinement layer 230 is 2E18cm -3 ～5E18 cm -3 . The thickness of the first confinement layer 230 may be 200nm to 1000nm, and preferably, the thickness of the first confinement layer 230 is 500nm. The material of the first confinement layer 230 includes, but is not limited to, alInP.
The first active layer 240 includes a first multiple quantum well structure, which is a multiple quantum well structure in which first well layers and first barrier layers alternately grow for a preset period number P.
The value range of the preset cycle number P is 3-20 pairs, and preferably, the value of the preset cycle number P is 12 pairs. The material of the first well layer may be Al a Ga 1-a As, wherein, the value of a ranges from 0.1 to 0.2, and preferably, the value of a is 0.15. The thickness of the single layer of the first well layer may be 6nm to 20nm, and preferably, the thickness of the single layer of the first well layer is 12nm. The material of the first barrier layer is Al b Ga 1-b As, wherein b has a value in the range of 0.35 to 0.5, preferably b has a value of 0.4. The thickness of the single layer of the first barrier layer may be 20nm to 40nm, and preferably, the thickness of the single layer of the first barrier layer is 20nm.
The second confinement layer 250 is used to provide holes and confine light field distribution, and the first confinement layer 230 and the second confinement layer 250 can confine minority carriers from overflowing the multiple quantum well layer and improve the composite light emitting efficiency; also serves as an important window so that photons emitted from the multiple quantum well layers can pass through the first confinement layer 230 and the second confinement layer 250 very easily, thereby improving the light emitting efficiency of the dual-junction infrared LED epitaxial structure.
The second confinement layer 250 is doped with a first type dopant, such as a P-type dopant, and may be at least one of carbon (C), magnesium (Mg), and zinc (Zn), but is not limited thereto. Further, the first type dopant is preferably C, and the doping concentration of the first type dopant doped in the second confinement layer 250 is 1E18cm -3 ～2E18cm -3 . The thickness of the second confinement layer 250 may be 500nm to 1200nm, and preferably, the thickness of the second confinement layer 250 is 600nm. The material of the second confinement layer 250 includes, but is not limited to, alInP.
The second LED structure 400 includes, in order from bottom to top, a third semiconductor layer, a second active layer 420, and a fourth semiconductor layer, where the third semiconductor layer is located on the tunneling junction 300. The radiation wavelength of the second active layer 420 may be 840nm to 870nm. The third semiconductor layer includes a third confinement layer 410.
The third confinement layer 410 is doped with a second type dopant, such as an N-type dopant, and may be at least one of silicon (Si) and tellurium (Te), but is not limited thereto. Further, the second type dopant is preferably Si, and the doping concentration of the second type dopant in the third confinement layer 410 is 1E18cm -3 ～2E18cm -3 . The material of the third confinement layer 410 includes, but is not limited to, alGaAs. The thickness of the third confinement layer 410 may be 200nm to 1000nm, and preferably, the thickness of the third confinement layer 410 is 500nm.
The second active layer 420 includes a second multiple quantum well structure, which is a multiple quantum well structure in which a second well layer and a second barrier layer alternately grow for a preset period number Q.
The value range of the preset cycle number Q is 1-12 pairs, and preferably, the value of the preset cycle number Q is 12 pairs. The material of the second well layer may be In c Ga 1-c As, wherein, the value of c is in the range of 0.1 to 0.15, and preferably, the value of c is 0.1. A thickness of the second well layer may be 6nm to 20nm, preferably, a thickness of the first well layerThe thickness of the two-well layer was 6nm. The material of the second barrier layer is Al d Ga 1-d As, wherein d has a value in the range of 0.15 to 0.4, preferably d has a value of 0.25. The thickness of the single layer of the second well layer may be 15nm to 30nm, and preferably, the thickness of the single layer of the second well layer is 20nm.
The fourth semiconductor layer includes, in order from bottom to top, a fourth confinement layer 430, a second window layer 440, and a second ohmic contact layer 450, where the fourth confinement layer 430 is located on the second active layer 420.
The fourth confinement layer 430 is doped with a first type dopant, such as a P-type dopant, and may be at least one of carbon (C), magnesium (Mg), and zinc (Zn), but is not limited thereto. Further, the first type dopant is preferably C, and the doping concentration of the first type dopant doped in the fourth confinement layer 430 is 2E18cm -3 ～5E18cm -3 . The thickness of the fourth confinement layer 430 may be 500nm to 1200nm, and preferably, the thickness of the fourth confinement layer 430 is 600nm. The material of the fourth confinement layer 430 includes, but is not limited to, alGaAs.
The second window layer 440 is doped with a first type dopant, such as a P-type dopant, and may be at least one of carbon (C), magnesium (Mg), and zinc (Zn), but is not limited thereto. Further, the first type dopant is preferably C, and the doping concentration of the first type dopant doped in the second window layer 440 is 3E18cm -3 ～5E18 cm -3 . The thickness of the second window layer 440 may be 500nm to 2500nm, and preferably, the thickness of the second window layer 440 is 1200nm. The material of the second window layer 440 includes, but is not limited to AlGaAs, where the Al component in the fourth confinement layer 430 is greater than the Al component in the second window layer 440, which is beneficial to confining carriers, increasing radiative recombination, and improving photoelectric efficiency.
The second ohmic contact layer 450 is for forming an ohmic contact with the metal electrode. The second ohmic contact layer 450 is doped with a first type dopant, for example, a P-type dopant, and may be at least one of carbon (C), magnesium (Mg), and zinc (Zn), but is not limited thereto. Further, the first type dopant is preferably C. The thickness of the second ohmic contact layer 450 may be 20nm to 100nm, and preferably, the thickness of the second ohmic contact layer 450 is 50nm. The material of the second ohmic contact layer 450 includes, but is not limited to, gaP.
Fig. 3 is a flowchart of a method for manufacturing a dual-junction infrared LED epitaxial structure according to the present embodiment. As shown in fig. 3, the present embodiment provides a method for preparing a dual-junction infrared LED epitaxial structure, where each step of the preparation method may use any one of a Metal Organic Chemical Vapor Deposition (MOCVD) process, a Molecular Beam Epitaxy (MBE) process, or an ultra-high vacuum chemical vapor deposition (UHVCVD), and preferably, each step of the preparation method uses a MOCVD process. The preparation method comprises the following steps:
step S21: providing a substrate 100;
step S22: the first LED structure 200, the tunnel junction 300 and the second LED structure 400 are sequentially formed on the substrate 100 from bottom to top, wherein the radiation wavelength of the first LED structure 200 is 740nm to 760nm, and the radiation wavelength of the second LED structure 400 is 840nm to 870nm.
In step S22, the first LED structure includes a first active layer 240, and the radiation wavelength of the first active layer 240 is 740nm to 760nm. The first active layer 240 is a multiple quantum well structure with alternately grown first well layers and first barrier layers of preset periods, and the first well layers are made of Al a Ga 1-a As, wherein the value range of a is 0.1-0.2; the material of the first barrier layer is Al b Ga 1-b As, wherein, the value range of b is 0.35-0.5. The value range of the preset cycle number is 3-20 pairs. The thickness of the first well layer is 6-20 nm, and the thickness of the first barrier layer is 20-40 nm.
The first LED structure further includes a first ohmic contact layer 210, a first window layer 220, a first confinement layer 230, and a second confinement layer 250, where the first ohmic contact layer 210, the first window layer 220, the first confinement layer 230, the first active layer 240, and the second confinement layer 250 are sequentially disposed from bottom to top, and N-type dopants are doped in the first ohmic contact layer 210, the first window layer 220, and the first confinement layer 230, and P-type dopants are doped in the second confinement layer 250.
The second LED structure includes a second active layer 420, and the radiation wavelength of the second active layer 420 is 840nm to 870nm. The second active layer 420 is a multiple quantum well structure with alternately grown second well layers and second barrier layers of preset periods, and the second well layers are made of In c Ga 1-c As, wherein the value range of c is 0.1-0.15; the material of the second barrier layer is Al d Ga 1-d As, wherein d has a value ranging from 0.15 to 0.4. The value range of the preset cycle number Q is 1-12 pairs. The thickness of the single-layer second well layer is 6-20 nm, and the thickness of the single-layer second well layer is 15-30 nm.
The second LED structure further includes a third confinement layer 410, a fourth confinement layer 430, a second window 440, and a second ohmic contact layer 450, where the third confinement layer 410, the second active layer 420, the fourth confinement layer 430, the second window layer 440, and the second ohmic contact layer 450 are sequentially disposed from bottom to top, and N-type dopants are doped in the third confinement layer 410, and P-type dopants are doped in the fourth confinement layer 430, the second window layer 440, and the second ohmic contact layer 450.
In summary, the invention provides a tunneling junction and a preparation method thereof, a dual-junction infrared LED epitaxial structure and a preparation method thereof, wherein the tunneling junction sequentially comprises a first doping layer, a graded doping layer and a second doping layer from bottom to top, the first doping layer and the graded doping layer are doped with dopants of the same type, the first doping layer and the second doping layer are doped with dopants of different types, the graded doping layer comprises a P component and an As component, the graded doping layer is a graded layer of the P component and the As component, the variation trend of the P component and the As component is opposite, and through the gradual change trend of the As and the P in the graded doping layer from bottom to top, the effective switching of the As and the P is realized, the interface quality and the crystal growth quality are effectively improved, the series resistance is reduced, the working voltage is reduced, and the photoelectric conversion efficiency is improved. The invention also provides a semiconductor device comprising the first doped layer (Al x1 Ga 1-x1 As) and a second doped layer (GaInSb z P 1-z ) Interposed graded doped layer (Al x2 Ga 1-x2 As y P 1-y ) The interface quality and the crystal growth quality are effectively improved, the series resistance is reduced, and the working voltage is reduced. In addition, a second doped layer (GaInSb z P 1-z ) The quality of the crystal is improved, the tunneling peak current and the tunneling characteristic are improved, and the tunneling voltage is reduced. According to the invention, the radiation wavelength of the first LED structure is 740-760 nm, the radiation wavelength of the second LED structure is 840-870 nm, namely, the first LED structure and the second LED structure with two different radiation wavelengths are adopted to form a double-junction infrared LED epitaxial structure, so that the light supplementing is carried out on the conventional 840-870 nm wave band by near infrared rays with the wave band of 740-760 nm, the night vision effect of the infrared LED is enhanced, and the application of the infrared LED in security monitoring is facilitated.
Furthermore, unless specifically stated or indicated otherwise, the description of the terms "first," "second," and the like in the specification merely serve to distinguish between various components, elements, steps, etc. in the specification, and do not necessarily represent a logical or sequential relationship between various components, elements, steps, etc.
It will be appreciated that although the invention has been described above in terms of preferred embodiments, the above embodiments are not intended to limit the invention. Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art without departing from the scope of the technology, or the technology can be modified to be equivalent. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.

Claims (24)

1. The tunneling junction is characterized by sequentially comprising a first doping layer, a graded doping layer and a second doping layer from bottom to top, wherein the first doping layer and the graded doping layer are doped with dopants of the same type, the first doping layer and the second doping layer are doped with dopants of different types, the graded doping layer comprises a P component and an As component, the graded doping layer is a graded layer of the P component and the As component, and the change trend of the P component and the As component is opposite.
2. The tunnel junction of claim 1 wherein said P-component increases gradually from bottom to top and said As-component decreases gradually from bottom to top.
3. The tunneling junction of claim 2, wherein,
the material of the first doped layer is Al x1 Ga 1-x1 As, wherein the value range of x1 is 0.1-0.3;
the material of the graded doped layer is Al x2 Ga 1-x2 As y P 1-y Wherein, the value range of x2 is 0.1-0.3, and the value range of y is 0.8-1; and
the material of the second doped layer is GaInSb z P 1-z Wherein, the value range of z is 0 to 0.02.
4. The tunneling junction of claim 3 wherein said graded doped layer material comprises a Sb composition and said Sb composition is greater than 0 and less than or equal to 2%.
5. The tunneling junction of claim 1, wherein said first doped layer and graded doped layer are both doped with P-type dopants and said second doped layer is doped with N-type dopants.
6. The tunneling junction of claim 1, wherein,
the thickness of the first doping layer is 10-30 nm, the thickness of the gradual change doping layer is 2-10 nm, and the thickness of the second doping layer is 2-20 nm.
7. The preparation method of the tunneling junction is characterized by comprising the following steps of:
forming a first doped layer;
forming a graded doping layer on the first doping layer, wherein the graded doping layer comprises a P component and an As component, the graded doping layer is a graded layer of the P component and the As component, and the change trend of the P component and the change trend of the As component are opposite; and
and forming a second doped layer on the graded doped layer, wherein the first doped layer and the graded doped layer are doped with the same type of dopant, and the first doped layer and the second doped layer are doped with different types of dopant.
8. The method of claim 7, wherein the P component is gradually increased from bottom to top and the As component is gradually decreased from bottom to top.
9. The method of manufacturing a tunnel junction according to claim 8, wherein,
the material of the first doped layer is Al x1 Ga 1-x1 As, wherein the value range of x1 is 0.1-0.3;
the material of the graded doped layer is Al x2 Ga 1-x2 As y P 1-y Wherein, the value range of x2 is 0.1-0.3, and the value range of y is 0.8-1; and
the material of the second doped layer is GaInSb z P 1-z Wherein, the value range of z is 0 to 0.02.
10. The method of claim 9, wherein the graded doped layer comprises a Sb component in a material, and the Sb component is greater than 0 and less than or equal to 2%.
11. The method of manufacturing a tunnel junction of claim 7 wherein said first doped layer and said graded doped layer are both doped with P-type dopants and said second doped layer is doped with N-type dopants.
12. The method of manufacturing a tunnel junction according to claim 7, wherein,
the thickness of the first doping layer is 10-30 nm, the thickness of the gradual change doping layer is 2-10 nm, and the thickness of the second doping layer is 2-20 nm.
13. A dual junction infrared LED epitaxial structure comprising a tunneling junction according to any of claims 1-6, further comprising a first LED structure and a second LED structure stacked on a substrate from bottom to top, the tunneling junction being located between the first LED structure and the second LED structure.
14. The dual junction infrared LED epitaxial structure of claim 13, wherein the first LED structure has a radiation wavelength of 740nm to 760nm and the second LED structure has a radiation wavelength of 840nm to 870nm.
15. The dual-junction infrared LED epitaxial structure of claim 13, wherein the first LED structure comprises a first active layer, the first active layer being a multiple quantum well structure in which a first well layer and a first barrier layer alternately grow for a predetermined number of cycles, the first well layer being made of Al a Ga 1-a As, wherein the value range of a is 0.1-0.2; the material of the first barrier layer is Al b Ga 1-b As, wherein, the value range of b is 0.35-0.5.
16. The dual-junction infrared LED epitaxial structure of claim 15, further comprising a first ohmic contact layer, a first window layer, a first confinement layer, and a second confinement layer, the first ohmic contact layer, the first window layer, the first confinement layer, the first active layer, and the second confinement layer being disposed in a bottom-to-top order, wherein the first ohmic contact layer, the first window layer, and the first confinement layer are doped with N-type dopants, and the second confinement layer is doped with P-type dopants.
17. The dual junction infrared LED epitaxial structure of claim 13, wherein the second LEThe D structure comprises a second active layer, wherein the second active layer is a multi-quantum well structure with alternately grown second well layers and second barrier layers with preset periods, and the second well layer is made of In c Ga 1-c As, wherein the value range of c is 0.1-0.15; the material of the second barrier layer is Al d Ga 1-d As, wherein d has a value ranging from 0.15 to 0.4.
18. The dual-junction infrared LED epitaxial structure of claim 17, further comprising a third confinement layer, a fourth confinement layer, a second window layer, and a second ohmic contact layer, wherein the third confinement layer, the second active layer, the fourth confinement layer, the second window layer, and the second ohmic contact layer are sequentially disposed from bottom to top, wherein the third confinement layer is doped with an N-type dopant, and wherein the fourth confinement layer, the second window layer, and the second ohmic contact layer are each doped with a P-type dopant.
19. The preparation method of the double-junction infrared LED epitaxial structure is characterized by comprising the following steps of:
providing a substrate;
sequentially forming a first LED structure, a tunneling junction and a second LED structure on the substrate from bottom to top;
wherein the tunnel junction is prepared by a method of preparing a tunnel junction according to any one of claims 7 to 12.
20. The method of claim 19, wherein the first LED structure has a radiation wavelength of 740nm to 760nm and the second LED structure has a radiation wavelength of 840nm to 870nm.
21. The method for manufacturing a dual-junction infrared LED epitaxial structure of claim 19, wherein the first LED structure comprises a first active layer, the first active layer is a multiple quantum well structure in which a first well layer and a first barrier layer alternately grow for a preset period number, and the material of the first well layer is Al a Ga 1-a As, wherein the value range of a is 0.1-0.2; the material of the first barrier layer is Al b Ga 1-b As, wherein, the value range of b is 0.35-0.5.
22. The method for manufacturing a dual-junction infrared LED epitaxial structure of claim 21, wherein the first LED structure further comprises a first ohmic contact layer, a first window layer, a first confinement layer and a second confinement layer, the first ohmic contact layer, the first window layer, the first confinement layer, the first active layer and the second confinement layer are sequentially arranged from bottom to top, wherein N-type dopants are doped in the first ohmic contact layer, the first window layer and the first confinement layer, and P-type dopants are doped in the second confinement layer.
23. The method for manufacturing a dual-junction infrared LED epitaxial structure of claim 19, wherein the second LED structure comprises a second active layer, the second active layer is a multiple quantum well structure In which a second well layer and a second barrier layer alternately grow for a preset period number, and the material of the second well layer is In c Ga 1-c As, wherein the value range of c is 0.1-0.15; the material of the second barrier layer is Al d Ga 1-d As, wherein d has a value ranging from 0.15 to 0.4.
24. The method for manufacturing a dual-junction infrared LED epitaxial structure of claim 23, wherein the second LED structure further comprises a third confinement layer, a fourth confinement layer, a second window layer and a second ohmic contact layer, wherein the third confinement layer, the second active layer, the fourth confinement layer, the second window layer and the second ohmic contact layer are sequentially arranged from bottom to top, wherein N-type dopants are doped in the third confinement layer, and P-type dopants are doped in the fourth confinement layer, the second window layer and the second ohmic contact layer.
CN202310676306.8A 2023-06-08 2023-06-08 Tunneling junction and preparation method thereof, double-junction infrared LED epitaxial structure and preparation method thereof Pending CN116759499A (en)

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