Infrared light emitting diode and method of manufacturing the same
By designing a waveguide layer with an asymmetric Al composition distribution in an infrared light-emitting diode, the problems of low luminous efficiency and insufficient aging reliability were solved, and voltage stability and efficiency were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAMEN SILAN ADVANCED COMPOUND SEMICON CO LTD
- Filing Date
- 2022-09-29
- Publication Date
- 2026-05-29
AI Technical Summary
Existing infrared LEDs have low luminous efficiency, insufficient stability in aging reliability testing, and their operating voltage is prone to increase.
In infrared light-emitting diodes, by forming a first waveguide layer and a second waveguide layer on both sides of the quantum well layer, the Al composition of the first waveguide layer gradually changes from low to high, and the Al composition of the second waveguide layer gradually changes from low to high, forming an asymmetric Al composition distribution, so as to reduce the potential barrier difference between electrons and holes and increase the probability of carrier recombination luminescence.
This improves the luminous efficiency of infrared LEDs, enhances the stability of aging reliability testing, and avoids the increase in operating voltage.
Smart Images
Figure CN115548186B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor technology, and in particular to an infrared light-emitting diode and its manufacturing method. Background Technology
[0002] Light-emitting diodes (LEDs) are semiconductor solid-state light-emitting devices with advantages such as simple structure, light weight, and no pollution. They have been widely used in many fields such as digital, display, lighting, and plant engineering. They are known as environmentally friendly and energy-saving green lighting sources and hold huge business opportunities.
[0003] Infrared light-emitting diodes (LEDs) are an important type of LED, widely used in security monitoring, remote control, vehicle sensing, and closed-circuit television (CCTV). Existing infrared LEDs consist of a substrate, an n-type semiconductor layer, a quantum well layer, and a p-type semiconductor layer from bottom to top, and their luminous efficiency is relatively low. Therefore, improving the luminous efficiency of infrared LEDs has become a key research focus. Summary of the Invention
[0004] The purpose of this invention is to provide an infrared light-emitting diode and its manufacturing method, which improves the stability of aging reliability testing while avoiding the increase of the operating voltage of the infrared light-emitting diode and improving the luminous efficiency of the infrared light-emitting diode.
[0005] To achieve the above objectives, the present invention provides an infrared light-emitting diode, characterized in that it comprises, from bottom to top, a substrate, an n-type semiconductor layer, a first waveguide layer, a quantum well layer, a second waveguide layer, and a p-type semiconductor layer, wherein, in the bottom-up direction, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer gradually increases from low to high.
[0006] Optionally, the thickness of the second waveguide layer is less than the thickness of the first waveguide layer.
[0007] Optionally, the thickness of the first waveguide layer is 120nm to 420nm, and the thickness of the second waveguide layer is 20nm to 320nm.
[0008] Optionally, the first waveguide layer is made of Al. x Ga 1-x As, the material of the second waveguide layer is Al. y Ga 1- y As, 0 <x<1,0<y<1。
[0009] Optionally, the Al composition of the quantum well layer is less than the lowest Al composition in the first waveguide layer, and the Al composition of the quantum well layer is less than the lowest Al composition in the second waveguide layer.
[0010] Optionally, the n-type semiconductor layer includes, from bottom to top, an n-type buffer layer, an n-type etch stop layer, an n-type ohmic contact layer, an n-type window layer, and an n-type confinement layer.
[0011] Optionally, the p-type semiconductor layer includes a p-type confinement layer, a p-type window layer, and a p-type ohmic contact layer.
[0012] The present invention also provides a method for manufacturing an infrared light-emitting diode, comprising:
[0013] Provide a substrate;
[0014] An n-type semiconductor layer, a first waveguide layer, a quantum well layer, a second waveguide layer, and a p-type semiconductor layer are sequentially formed on the substrate, wherein, in the bottom-up direction, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer gradually increases from low to high.
[0015] Optionally, the thickness of the second waveguide layer is less than the thickness of the first waveguide layer.
[0016] Optionally, the thickness of the first waveguide layer is 120nm to 420nm, and the thickness of the second waveguide layer is 20nm to 320nm.
[0017] Optionally, the first waveguide layer is made of Al. x Ga 1-x As, the material of the second waveguide layer is Al. y Ga 1- y As, 0 <x<1,0<y<1。
[0018] Optionally, the Al composition of the quantum well layer is less than the lowest Al composition in the first waveguide layer, and the Al composition of the quantum well layer is less than the lowest Al composition in the second waveguide layer.
[0019] Optionally, the n-type semiconductor layer includes, from bottom to top, an n-type buffer layer, an n-type etch stop layer, an n-type ohmic contact layer, an n-type window layer, and an n-type confinement layer.
[0020] Optionally, the p-type semiconductor layer includes a p-type confinement layer, a p-type window layer, and a p-type ohmic contact layer.
[0021] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:
[0022] The infrared light-emitting diode and its manufacturing method of the present invention form a first waveguide layer and a second waveguide layer on both sides of a quantum well layer, and in the direction from bottom to top, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer gradually increases from low to high. This improves the stability of aging reliability testing while avoiding an increase in the operating voltage of the infrared light-emitting diode, and also improves the luminous efficiency of the infrared light-emitting diode. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the structure of an infrared light-emitting diode according to an embodiment of the present invention;
[0024] Figure 2 This is a flowchart of a method for manufacturing an infrared light-emitting diode according to an embodiment of the present invention.
[0025] Among them, the appendix Figures 1-2 The annotations in the attached figures are explained as follows:
[0026] 11-Substrate; 12-n-type semiconductor layer; 121-n-type buffer layer; 122-n-type etch stop layer; 123-n-type ohmic contact layer; 124-n-type window layer; 125-n-type confinement layer; 13-first waveguide layer; 14-quantum well layer; 15-second waveguide layer; 16-p-type semiconductor layer; 161-p-type confinement layer; 162-p-type window layer; 163-p-type ohmic contact layer. Detailed Implementation
[0027] To make the objectives, advantages, and features of the present invention clearer, the infrared light-emitting diode and its manufacturing method proposed in this invention will be described in further detail below. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the objectives of the embodiments of the present invention.
[0028] An embodiment of the present invention provides an infrared light-emitting diode, comprising, from bottom to top, a substrate, an n-type semiconductor layer, a first waveguide layer, a quantum well layer, a second waveguide layer, and a p-type semiconductor layer, wherein, in the bottom-up direction, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer gradually increases from low to high.
[0029] See below. Figure 1 A more detailed description of the infrared LED provided in this embodiment is provided below. Figure 1 This is also a longitudinal cross-sectional view of an infrared light-emitting diode.
[0030] The infrared light-emitting diode includes, from bottom to top, a substrate 11, an n-type semiconductor layer 12, a first waveguide layer 13, a quantum well layer 14, a second waveguide layer 15, and a p-type semiconductor layer 16. In the bottom-up direction (i.e., along the growth direction), the Al composition of the first waveguide layer 13 gradually increases from low to high, and the Al composition of the second waveguide layer 15 also gradually increases from low to high. This means that waveguide layers with asymmetrical Al composition distribution are formed on the upper and lower sides of the quantum well layer 14. Therefore, the Al composition of the first waveguide layer 13 is lowest on the side closest to the n-type semiconductor layer 12 and highest on the side closest to the quantum well layer 14; similarly, the Al composition of the second waveguide layer 15 is lowest on the side closest to the quantum well layer 14 and highest on the side closest to the p-type semiconductor layer 16.
[0031] The Al composition gradient of the first waveguide layer 13 can be linear, and the Al composition gradient of the second waveguide layer 15 can be linear. The range and slope of the Al composition gradients of the first waveguide layer 13 and the second waveguide layer 15 are the same.
[0032] Specifically, by defining the Al composition of the first waveguide layer 13 as gradually increasing from low to high in the bottom-up direction, and the Al composition of the second waveguide layer 15 as gradually increasing from low to high, the average potential barrier for electrons entering the quantum well layer 14 from the n-type semiconductor layer 12 is reduced, and the average potential barrier for holes entering the quantum well layer 14 from the p-type semiconductor layer 16 is also reduced, thereby effectively reducing the operating voltage of the infrared light-emitting diode; at the same time, it reduces carrier leakage within the quantum well layer 14, thereby improving the stability of aging reliability testing.
[0033] Furthermore, by defining the Al composition of the first waveguide layer 13 as gradually increasing from low to high in the bottom-up direction, which is equivalent to electrons moving from a low potential barrier to a high potential barrier, the drift rate of electrons can be reduced. By defining the Al composition of the second waveguide layer 15 as gradually increasing from low to high in the bottom-up direction, which is equivalent to holes moving from a high potential barrier to a low potential barrier, the drift rate of holes can be increased. The combination of these two factors increases the probability of electrons and holes recombine and emit light within the quantum well layer 14, thereby improving the luminous efficiency.
[0034] The substrate 11 can be made of at least one of semiconductor materials such as silicon, germanium, silicon carbide, and gallium arsenide.
[0035] The first waveguide layer 13 is made of Al. x Ga 1-x As, the material of the second waveguide layer 15 is Al. y Ga 1-yAs, 0 < x < 1, 0 < y < 1. The first waveguide layer 13 and the second waveguide layer 15 are undoped layers.
[0036] Preferably, the thickness of the second waveguide layer 15 is less than that of the first waveguide layer 13. Since the effective mass of holes is larger than that of electrons, the drift velocity of electrons is faster, and the migration velocity of electrons in the device is faster. By defining the thickness of the second waveguide layer 15 to be less than that of the first waveguide layer 13, the average free path of electrons can be extended, and the probability of recombination luminescence of electrons and holes in the quantum well layer 14 can be increased, thus improving the luminescence efficiency.
[0037] Preferably, the thickness of the first waveguide layer 13 is 120 nm to 420 nm, and more preferably, the thickness of the first waveguide layer 13 is 320 nm; preferably, the thickness of the second waveguide layer 15 is 20 nm to 320 nm, and more preferably, the thickness of the second waveguide layer 15 is 120 nm.
[0038] Preferably, the Al composition of the quantum well layer 14 is less than the lowest Al composition in the first waveguide layer 13, and the Al composition of the quantum well layer 14 is less than the lowest Al composition in the second waveguide layer 15, so as to avoid too high Al composition in the quantum well layer 14 resulting in too high operating voltage.
[0039] The material of the quantum well layer 14 can be InGaAs / AlGaAs, etc.
[0040] Preferably, the quantum well layer 14 is a multi-quantum well structure, that is, a periodic structure composed of quantum wells and quantum barriers, and the number of periods is preferably 6 to 30 pairs, and more preferably 12.
[0041] Preferably, the thickness of the quantum well layer 14 is 50 nm to 2000 nm, and more preferably, the thickness of the quantum well layer 14 is 900 nm.
[0042] The n-type semiconductor layer 12 includes an n-type buffer layer 121, an n-type etch stop layer 122, an n-type ohmic contact layer 123, an n-type window layer 124, and an n-type confinement layer 125 from bottom to top.
[0043] Among them, the n-type buffer layer 121 is used to eliminate the influence of the surface defects of the substrate 11 on the infrared light-emitting diode to the greatest extent, reduce the probability of defects and dislocations of the infrared light-emitting diode, and provide a flat interface for the growth of the next structure.
[0044] The material of the n-type buffer layer 121 is preferably GaAs, but is not limited thereto.
[0045] The dopant in the n-type buffer layer 121 can be at least one of n-type dopant such as silicon and tellurium. Further, the n-type dopant is preferably silicon.
[0046] Preferably, the thickness of the n-type buffer layer 121 is 100nm to 300nm, and more preferably, the thickness of the n-type buffer layer 121 is 150nm.
[0047] The n-type etch stop layer 122 is used as an etch stop layer in the subsequent etching process when fabricating device structures, so as to prevent the structure below the n-type etch stop layer 122 from being etched.
[0048] The material of the n-type corrosion stopping layer 122 is preferably GaAs, but is not limited thereto.
[0049] The dopant in the n-type etch stop layer 122 can be at least one of n-type dopants such as silicon and tellurium. Further, the n-type dopant is preferably silicon.
[0050] Preferably, the thickness of the n-type corrosion stop layer 122 is 100nm to 300nm, and more preferably, the thickness of the n-type corrosion stop layer 122 is 150nm.
[0051] The n-type ohmic contact layer 123 is used to form an ohmic contact with a metal electrode.
[0052] The material of the n-type ohmic contact layer 123 can be InGaAs or GaAs, preferably GaAs, but not limited to this.
[0053] The dopant in the n-type ohmic contact layer 123 can be at least one of n-type dopant such as silicon and tellurium. Further, the n-type dopant is preferably silicon.
[0054] Preferably, the thickness of the n-type ohmic contact layer 123 is 20nm to 150nm, and more preferably, the thickness of the n-type ohmic contact layer 123 is 50nm.
[0055] The n-type window layer 124 is used as a light-emitting window and for current expansion.
[0056] The dopant in the n-type window layer 124 can be at least one of n-type dopant such as silicon and tellurium. Further, the n-type dopant is preferably silicon, and the silicon doping concentration can be 0.7E18 cm⁻¹. -3 ~5E18cm -3 .
[0057] Preferably, the thickness of the n-type window layer 124 is 1.5μm to 8μm, and more preferably, the thickness of the n-type window layer 124 is 6μm.
[0058] The n-type confinement layer 125 is used to provide electrons.
[0059] The material of the n-type confinement layer 125 is preferably AlGaAs, but is not limited thereto.
[0060] The dopant in the n-type confinement layer 125 can be at least one of n-type dopant such as silicon and tellurium. Further, the n-type dopant is preferably silicon.
[0061] Preferably, the thickness of the n-type confinement layer 125 is 200nm to 1000nm, and more preferably, the thickness of the n-type confinement layer 125 is 500nm.
[0062] In addition, the p-type semiconductor layer 16 includes a p-type confinement layer 161, a p-type window layer 162, and a p-type ohmic contact layer 163.
[0063] The p-type confinement layer 161 is used to provide holes.
[0064] Furthermore, the functions of the n-type confinement layer 125 and the p-type confinement layer 161 include: firstly, limiting the overflow of minority carriers from the quantum well layer 14 to improve recombination luminescence efficiency; secondly, serving as an important window to allow photons emitted from the quantum well layer 14 to easily pass through the n-type confinement layer 125 and the p-type confinement layer 161, thereby improving the luminescence efficiency of the infrared light-emitting diode.
[0065] The material of the p-type confinement layer 161 is preferably AlGaAs, but is not limited thereto.
[0066] The dopant in the p-type confinement layer 161 can be at least one of p-type dopant such as carbon, magnesium, and zinc. Further, the p-type dopant is preferably carbon.
[0067] Preferably, the thickness of the p-type confinement layer 161 is 200 nm to 1500 nm, and more preferably, the thickness of the p-type confinement layer 161 is 600 nm.
[0068] The p-type window layer 162 is used as a light-emitting window and for current expansion.
[0069] The material of the p-type window layer 162 is preferably AlGaAs, but is not limited thereto.
[0070] The dopant in the p-type window layer 162 can be at least one of p-type dopant such as carbon, magnesium, and zinc. Further, the p-type dopant is preferably carbon.
[0071] The thickness of the p-type window layer 162 is 200nm to 3000nm, and more preferably, the thickness of the p-type window layer 162 is 1200nm.
[0072] The p-type ohmic contact layer 163 is used to form an ohmic contact with another metal electrode.
[0073] The material of the p-type ohmic contact layer 163 is preferably GaP, but is not limited thereto.
[0074] The dopant in the p-type ohmic contact layer 163 is preferably carbon.
[0075] The thickness of the p-type ohmic contact layer 163 is 20nm to 100nm, and more preferably, the thickness of the p-type ohmic contact layer 163 is 50nm.
[0076] In summary, the infrared light-emitting diode provided by this invention includes, from bottom to top, a substrate, an n-type semiconductor layer, a first waveguide layer, a quantum well layer, a second waveguide layer, and a p-type semiconductor layer. Specifically, in the bottom-up direction, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer also gradually increases from low to high. The infrared light-emitting diode provided by this invention improves the stability of aging reliability testing while avoiding an increase in the operating voltage of the infrared light-emitting diode, and also improves the luminous efficiency of the infrared light-emitting diode.
[0077] One embodiment of the present invention provides a method for manufacturing an infrared light-emitting diode, see reference. Figure 2 , Figure 2 This is a flowchart of a method for manufacturing an infrared light-emitting diode according to an embodiment of the present invention. The method for manufacturing the infrared light-emitting diode includes:
[0078] Step S1, provide a substrate;
[0079] Step S2: An n-type semiconductor layer, a first waveguide layer, a quantum well layer, a second waveguide layer, and a p-type semiconductor layer are sequentially formed on the substrate. In the bottom-up direction, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer gradually increases from low to high.
[0080] See below. Figure 1 The manufacturing method of the infrared light-emitting diode provided in this embodiment will be described in more detail.
[0081] According to step S1, a substrate 11 is provided. The substrate 11 can be made of at least one of semiconductor materials such as silicon, germanium, silicon carbide, and gallium arsenide.
[0082] According to step S2, an n-type semiconductor layer 12, a first waveguide layer 13, a quantum well layer 14, a second waveguide layer 15, and a p-type semiconductor layer 16 are sequentially formed on the substrate 11. In the bottom-up direction (i.e., along the growth direction), the Al composition of the first waveguide layer 13 gradually increases from low to high, and the Al composition of the second waveguide layer 15 also gradually increases from low to high. This means that waveguide layers with asymmetrical Al composition distribution are formed on the upper and lower sides of the quantum well layer 14. Therefore, the Al composition of the first waveguide layer 13 is lowest on the side closest to the n-type semiconductor layer 12 and highest on the side closest to the quantum well layer 14; similarly, the Al composition of the second waveguide layer 15 is lowest on the side closest to the quantum well layer 14 and highest on the side closest to the p-type semiconductor layer 16.
[0083] The Al composition gradient of the first waveguide layer 13 can be linear, and the Al composition gradient of the second waveguide layer 15 can be linear. The range and slope of the Al composition gradients of the first waveguide layer 13 and the second waveguide layer 15 are the same.
[0084] Specifically, by defining the Al composition of the first waveguide layer 13 as gradually increasing from low to high in the bottom-up direction, and the Al composition of the second waveguide layer 15 as gradually increasing from low to high, the average potential barrier for electrons entering the quantum well layer 14 from the n-type semiconductor layer 12 is reduced, and the average potential barrier for holes entering the quantum well layer 14 from the p-type semiconductor layer 16 is also reduced, thereby effectively reducing the operating voltage of the infrared light-emitting diode; at the same time, it reduces carrier leakage within the quantum well layer 14, thereby improving the stability of aging reliability testing.
[0085] Furthermore, by defining the Al composition of the first waveguide layer 13 as gradually increasing from low to high in the bottom-up direction, which is equivalent to electrons moving from a low potential barrier to a high potential barrier, the drift rate of electrons can be reduced. By defining the Al composition of the second waveguide layer 15 as gradually increasing from low to high in the bottom-up direction, which is equivalent to holes moving from a high potential barrier to a low potential barrier, the drift rate of holes can be increased. The combination of these two factors increases the probability of electrons and holes recombine and emit light within the quantum well layer 14, thereby improving the luminous efficiency.
[0086] The n-type semiconductor layer 12, the first waveguide layer 13, the quantum well layer 14, the second waveguide layer 15 and the p-type semiconductor layer 16 can be sequentially formed on the substrate 11 using any one of the following processes: metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or ultra-high vacuum chemical vapor deposition (UHVCVD). Preferably, metal-organic chemical vapor deposition is used.
[0087] The material of the first waveguide layer 13 is Al x Ga 1-x As, and the material of the second waveguide layer 15 is Al y Ga 1-y As, where 0 < x < 1 and 0 < y < 1. The first waveguide layer 13 and the second waveguide layer 15 are undoped layers.
[0088] Preferably, the thickness of the second waveguide layer 15 is less than that of the first waveguide layer 13. Since the effective mass of holes is larger than that of electrons, the drift velocity of electrons is faster, and the migration velocity of electrons in the device is faster. By defining the thickness of the second waveguide layer 15 to be less than that of the first waveguide layer 13, the average free path of electrons can be extended, and thus the probability of recombination luminescence of electrons and holes in the quantum well layer 14 can be increased, thereby improving the luminescence efficiency.
[0089] Preferably, the thickness of the first waveguide layer 13 is 120 nm to 420 nm, and more preferably, the thickness of the first waveguide layer 13 is 320 nm; preferably, the thickness of the second waveguide layer 15 is 20 nm to 320 nm, and more preferably, the thickness of the second waveguide layer 15 is 120 nm.
[0090] Preferably, the Al component of the quantum well layer 14 is less than the lowest Al component in the first waveguide layer 13, and the Al component of the quantum well layer 14 is less than the lowest Al component in the second waveguide layer 15, so as to avoid too high Al component in the quantum well layer 14 resulting in too high working voltage.
[0091] The material of the quantum well layer 14 can be InGaAs / AlGaAs, etc.
[0092] Preferably, the quantum well layer 14 is a multi-quantum well structure, that is, a periodic structure composed of quantum wells and quantum barriers, and the number of periods is preferably 6 to 30 pairs, and more preferably 12.
[0093] Preferably, the thickness of the quantum well layer 14 is 50 nm to 2000 nm, and more preferably, the thickness of the quantum well layer 14 is 900 nm.
[0094] The n-type semiconductor layer 12 includes an n-type buffer layer 121, an n-type etch stop layer 122, an n-type ohmic contact layer 123, an n-type window layer 124, and an n-type confinement layer 125 from bottom to top.
[0095] The n-type buffer layer 121 is used to minimize the impact of surface defects of the substrate 11 on the infrared light-emitting diode, reduce the probability of defects and dislocations in the infrared light-emitting diode, and provide a smooth interface for the growth of the next structure.
[0096] The material of the n-type buffer layer 121 is preferably GaAs, but is not limited thereto.
[0097] The dopant in the n-type buffer layer 121 can be at least one of n-type dopant such as silicon and tellurium. Further, the n-type dopant is preferably silicon.
[0098] Preferably, the thickness of the n-type buffer layer 121 is 100nm to 300nm, and more preferably, the thickness of the n-type buffer layer 121 is 150nm.
[0099] The n-type etch stop layer 122 is used as an etch stop layer in the subsequent etching process when fabricating device structures, so as to prevent the structure below the n-type etch stop layer 122 from being etched.
[0100] The material of the n-type corrosion stopping layer 122 is preferably GaAs, but is not limited thereto.
[0101] The dopant in the n-type etch stop layer 122 can be at least one of n-type dopants such as silicon and tellurium. Further, the n-type dopant is preferably silicon.
[0102] Preferably, the thickness of the n-type corrosion stop layer 122 is 100nm to 300nm, and more preferably, the thickness of the n-type corrosion stop layer 122 is 150nm.
[0103] The n-type ohmic contact layer 123 is used to form an ohmic contact with a metal electrode.
[0104] The material of the n-type ohmic contact layer 123 can be InGaAs or GaAs, preferably GaAs, but not limited to this.
[0105] The dopant in the n-type ohmic contact layer 123 can be at least one of n-type dopant such as silicon and tellurium. Further, the n-type dopant is preferably silicon.
[0106] Preferably, the thickness of the n-type ohmic contact layer 123 is 20nm to 150nm, and more preferably, the thickness of the n-type ohmic contact layer 123 is 50nm.
[0107] The n-type window layer 124 is used as a light-emitting window and for current expansion.
[0108] The dopant in the n-type window layer 124 can be at least one of n-type dopant such as silicon and tellurium. Further, the n-type dopant is preferably silicon, and the silicon doping concentration can be 0.7E18 cm⁻¹. -3 ~5E18cm -3 .
[0109] Preferably, the thickness of the n-type window layer 124 is 1.5μm to 8μm, and more preferably, the thickness of the n-type window layer 124 is 6μm.
[0110] The n-type confinement layer 125 is used to provide electrons.
[0111] The material of the n-type confinement layer 125 is preferably AlGaAs, but is not limited thereto.
[0112] The dopant in the n-type confinement layer 125 can be at least one of n-type dopant such as silicon and tellurium. Further, the n-type dopant is preferably silicon.
[0113] Preferably, the thickness of the n-type confinement layer 125 is 200nm to 1000nm, and more preferably, the thickness of the n-type confinement layer 125 is 500nm.
[0114] In addition, the p-type semiconductor layer 16 includes a p-type confinement layer 161, a p-type window layer 162, and a p-type ohmic contact layer 163.
[0115] The p-type confinement layer 161 is used to provide holes.
[0116] Furthermore, the functions of the n-type confinement layer 125 and the p-type confinement layer 161 include: firstly, limiting the overflow of minority carriers from the quantum well layer 14 to improve recombination luminescence efficiency; secondly, serving as an important window to allow photons emitted from the quantum well layer 14 to easily pass through the n-type confinement layer 125 and the p-type confinement layer 161, thereby improving the luminescence efficiency of the infrared light-emitting diode.
[0117] The material of the p-type confinement layer 161 is preferably AlGaAs, but is not limited thereto.
[0118] The dopant in the p-type confinement layer 161 can be at least one of p-type dopant such as carbon, magnesium, and zinc. Further, the p-type dopant is preferably carbon.
[0119] Preferably, the thickness of the p-type confinement layer 161 is 200 nm to 1500 nm, and more preferably, the thickness of the p-type confinement layer 161 is 600 nm.
[0120] The p-type window layer 162 is used as a light-emitting window and for current expansion.
[0121] The material of the p-type window layer 162 is preferably AlGaAs, but is not limited thereto.
[0122] The dopant in the p-type window layer 162 can be at least one of p-type dopant such as carbon, magnesium, and zinc. Further, the p-type dopant is preferably carbon.
[0123] The thickness of the p-type window layer 162 is 200nm to 3000nm, and more preferably, the thickness of the p-type window layer 162 is 1200nm.
[0124] The p-type ohmic contact layer 163 is used to form an ohmic contact with another metal electrode.
[0125] The material of the p-type ohmic contact layer 163 is preferably GaP, but is not limited thereto.
[0126] The dopant in the p-type ohmic contact layer 163 is preferably carbon.
[0127] The thickness of the p-type ohmic contact layer 163 is 20nm to 100nm, and more preferably, the thickness of the p-type ohmic contact layer 163 is 50nm.
[0128] In summary, the method for manufacturing an infrared light-emitting diode (LED) provided by this invention includes: providing a substrate; and sequentially forming an n-type semiconductor layer, a first waveguide layer, a quantum well layer, a second waveguide layer, and a p-type semiconductor layer on the substrate, wherein, in an upward direction, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer gradually increases from low to high. The method for manufacturing an infrared LED provided by this invention improves the stability of aging reliability testing while avoiding an increase in the operating voltage of the infrared LED, and also improves the luminous efficiency of the infrared LED.
[0129] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.
Claims
1. An infrared light-emitting diode, characterized in that, It includes, from bottom to top, a substrate, an n-type semiconductor layer, a first waveguide layer, a quantum well layer, a second waveguide layer, and a p-type semiconductor layer, wherein, in the bottom-up direction, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer gradually increases from low to high, and the first waveguide layer and the second waveguide layer are undoped layers.
2. The infrared light-emitting diode as described in claim 1, characterized in that, The thickness of the second waveguide layer is less than the thickness of the first waveguide layer.
3. The infrared light-emitting diode as described in claim 2, characterized in that, The thickness of the first waveguide layer is 120nm~420nm, and the thickness of the second waveguide layer is 20nm~320nm.
4. The infrared light-emitting diode as described in claim 1, characterized in that, The first waveguide layer is made of Al. x Ga 1- x As, the material of the second waveguide layer is Al. y Ga 1-y As, 0 <x<1,0<y<1。 5. The infrared light-emitting diode as described in claim 1, characterized in that, The Al composition of the quantum well layer is less than the lowest Al composition in the first waveguide layer, and the Al composition of the quantum well layer is less than the lowest Al composition in the second waveguide layer.
6. The infrared light-emitting diode as described in claim 1, characterized in that, The n-type semiconductor layer includes, from bottom to top, an n-type buffer layer, an n-type etch stop layer, an n-type ohmic contact layer, an n-type window layer, and an n-type confinement layer.
7. The infrared light-emitting diode as described in claim 1, characterized in that, The p-type semiconductor layer includes a p-type confinement layer, a p-type window layer, and a p-type ohmic contact layer.
8. A method for manufacturing an infrared light-emitting diode, characterized in that, include: Provide a substrate; An n-type semiconductor layer, a first waveguide layer, a quantum well layer, a second waveguide layer, and a p-type semiconductor layer are sequentially formed on the substrate. In the bottom-up direction, the Al composition of the first waveguide layer gradually increases from low to high, and the Al composition of the second waveguide layer gradually increases from low to high. The first waveguide layer and the second waveguide layer are undoped layers.
9. The method for manufacturing an infrared light-emitting diode as described in claim 8, characterized in that, The thickness of the second waveguide layer is less than the thickness of the first waveguide layer.
10. The method for manufacturing an infrared light-emitting diode as described in claim 9, characterized in that, The thickness of the first waveguide layer is 120nm~420nm, and the thickness of the second waveguide layer is 20nm~320nm.
11. The method for manufacturing an infrared light-emitting diode as described in claim 8, characterized in that, The first waveguide layer is made of Al. x Ga 1-x As, the material of the second waveguide layer is Al. y Ga 1-y As, 0 <x<1,0<y<1。 12. The method for manufacturing an infrared light-emitting diode as described in claim 8, characterized in that, The Al composition of the quantum well layer is less than the lowest Al composition in the first waveguide layer, and the Al composition of the quantum well layer is less than the lowest Al composition in the second waveguide layer.
13. The method for manufacturing an infrared light-emitting diode as described in claim 8, characterized in that, The n-type semiconductor layer includes, from bottom to top, an n-type buffer layer, an n-type etch stop layer, an n-type ohmic contact layer, an n-type window layer, and an n-type confinement layer.
14. The method for manufacturing an infrared light-emitting diode as described in claim 8, characterized in that, The p-type semiconductor layer includes a p-type confinement layer, a p-type window layer, and a p-type ohmic contact layer.