CN116154072B - LED epitaxial wafer for regulating and controlling quantum well carbon impurities and its preparation method, LED - Google Patents

Abstract

The invention provides an LED epitaxial wafer for regulating and controlling quantum well carbon impurities, a preparation method thereof and an LED, wherein the LED epitaxial wafer comprises a substrate, a first semiconductor layer, an active layer and a second semiconductor layer; the active layer comprises M composite quantum well layers and quantum barrier layers which are periodically and alternately arranged, the composite quantum well layers sequentially comprise a plurality of first carbon impurity regulating layers, quantum well layers and a plurality of second carbon impurity regulating layers which are stacked along the epitaxial direction, the carbon impurity content of the first carbon impurity regulating layers is decreased progressively along the epitaxial direction, the carbon impurity content of the second carbon impurity regulating layers is increased progressively along the epitaxial direction, and the carbon impurity concentrations of the first carbon impurity regulating layers and the second carbon impurity regulating layers are higher than the carbon impurity concentration of the quantum well layers.

Description

LED epitaxial wafer for regulating quantum well carbon impurity and preparation method thereof, LED

technical field

The invention belongs to the technical field of LEDs, and in particular relates to LED epitaxial wafers for regulating quantum well carbon impurities, a preparation method thereof, and LEDs.

Background technique

GaN-based blue light and green light-emitting devices represented by III-V nitride materials have outstanding advantages such as high brightness, low energy consumption, long life, short response time, and zero radiation, and have an extremely wide market. In the process of manufacturing semiconductor devices such as LEDs (light-emitting diodes), doping in GaN-based semiconductors is crucial. These extremely small amounts of impurities will play a decisive role in the chemical and physical properties of semiconductor materials. Of course, it will also seriously affect the quality of the semiconductor, because the existence of impurities will destroy the potential field generated by the atoms arranged in strict periodicity, and it is very likely to introduce energy levels in the forbidden band (allowing the energy state of ). Metal-organic compounds (MO sources) are indispensable in the process of growing nitride semiconductor materials (such as GaN, AlN, etc.). Organic compounds must contain C elements, and with the high-temperature growth of MOCVD, the MO source must undergo thermal decomposition. During the process of thermal decomposition, impurities containing C elements will grow and be incorporated into the epitaxial layer. At present, the main way to reduce the impurity of C element is to replace the MO source TMGa (trimethylgallium) with triethylgallium (TEGa).

After replacing TEGa, the C impurity content in the epitaxial layer will decrease, but because it is still an organic source, there must still be C impurities entering the epitaxial layer. C impurities in GaN are mainly formed by replacing Ga sites with C to generate donor energy levels, and C replaces N. Bit formation, generation of acceptor energy level, decrease of carrier concentration, increase of non-radiative recombination efficiency, leading to decrease of LED luminous efficiency.

Contents of the invention

In order to solve the above technical problems, the present invention provides an LED epitaxial wafer for regulating and controlling quantum well carbon impurities, a preparation method thereof, and an LED, which are used to solve the technical problems in the prior art.

In the first aspect, the embodiments of the present invention provide the following technical solutions, an LED epitaxial wafer for regulating quantum well carbon impurities, including a substrate and a first semiconductor layer, an active layer, and a second semiconductor layer sequentially deposited on the substrate layer;

The active layer includes M periodically alternately arranged composite quantum well layers and quantum barrier layers, and the composite quantum well layer sequentially includes stacked first carbon impurity control layers, quantum well layers and several stacked layers along the epitaxial direction. For the second carbon impurity control layer, the carbon impurity content of some of the first carbon impurity control layers decreases along the epitaxial direction, and the carbon impurity content of some of the second carbon impurity control layers increases along the epitaxial direction, and the first carbon impurity Both the carbon impurity concentration of the control layer and the second carbon impurity control layer are higher than the carbon impurity concentration of the quantum well layer.

Compared with the prior art, the beneficial effect of the present application is: the radius of the C impurity atoms in the quantum well of the present invention is close to that of Ga atoms or N atoms, so as to generate replacement atoms, and at the same time, when the impurity atoms become interstitial atoms, The InGaN lattice is distorted, which affects the crystal quality of InGaN materials, and the deposited composite quantum well layer includes the first carbon impurity control layer and the second carbon impurity control layer, which are grown under low pressure conditions and have a high V/III ratio. It can effectively reduce the C impurity content of the quantum well layer and improve the crystal quality of the quantum well layer. Secondly, the first carbon impurity control layer and the second carbon impurity control layer can also reduce the donor level due to the formation of C instead of Ga sites. Substituting the formation of N sites and generating acceptor energy levels leads to a decrease in carrier concentration and an increase in non-radiative recombination efficiency. Finally, the C impurity concentration is modulated by the first carbon impurity control layer and the second carbon impurity control layer to reduce the polarization of the quantum well. Effect, improve the wave function overlap of electrons and holes, and improve the luminous efficiency of LED.

Preferably, the first carbon impurity control layer and the second carbon impurity control layer are both GaN layers, AlGaN layers, InGaN layers, and BGaN layers.

Preferably, the carbon impurity concentration of the quantum well layer is less than 1E17 atoms/cm ³ .

Preferably, the composite quantum well layer has a thickness ranging from 1 nm to 10 nm.

Preferably, the thickness ratio of the first carbon impurity regulation layer, the quantum well layer and the second carbon impurity regulation layer ranges from 1:1:1 to 1:10:1.

Preferably, the value range of period M in which the composite quantum well layers and the quantum barrier layers are alternately arranged is: 1≤M≤20.

In the second aspect, the embodiments of the present invention also provide the following technical solutions, a method for preparing an LED epitaxial wafer that regulates quantum well carbon impurities, comprising the following steps:

providing a substrate;

depositing a first semiconductor layer on the substrate;

Alternately depositing M periods of composite quantum well layers and quantum barrier layers on the first semiconductor layer to form an active layer;

depositing a second semiconductor layer on said quantum barrier layer of the last period;

Wherein, the composite quantum well layer sequentially includes several first carbon impurity control layers, quantum well layers and several second carbon impurity control layers stacked along the epitaxial direction, and the carbon impurity content of the first carbon impurity control layers is along the The epitaxial direction decreases, and the carbon impurity content of several of the second carbon impurity control layers increases along the epitaxial direction, and the carbon impurity concentrations of the first carbon impurity control layer and the second carbon impurity control layer are higher than the quantum The carbon impurity concentration of the well layer.

Preferably, the growth temperature of the composite quantum well layer ranges from 700°C to 1000°C, the ratio of N ₂ /NH ₃ in the growth atmosphere ranges from 10:1 to 1:10, and the growth pressure ranges from 50 torr to 300 torr.

Preferably, the quantum barrier layer is specifically an AlGaN layer, its growth temperature ranges from 800° C. to 1000° C., its thickness ranges from 1 nm to 50 nm, its growth pressure ranges from 50 torr to 300 torr, and its Al composition ranges from 0.05 to 0.5.

In the third aspect, the embodiment of the present invention also provides the following technical solution, an LED comprising the above-mentioned LED epitaxial wafer for regulating quantum well carbon impurities.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the descriptions of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only of the present invention. For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without paying creative efforts.

Fig. 1 is the structural diagram of the LED epitaxial wafer of regulating quantum well carbon impurity that the embodiment of the present invention provides;

Fig. 2 is the structural diagram of the composite quantum well layer provided by the embodiment of the present invention;

FIG. 3 is a flow chart of a method for preparing an LED epitaxial wafer for regulating quantum well carbon impurities provided by an embodiment of the present invention.

Explanation of reference signs:

The present invention will be further described below in conjunction with the accompanying drawings.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the embodiments of the present invention and should not be construed as limitations of the present invention.

In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical ", "horizontal", "top", "bottom", "inner", "outer" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying Describes, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and operate in a specific orientation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

In the embodiments of the present invention, terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense unless otherwise clearly specified and limited. Disassembled connection, or integration; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present invention according to specific situations.

Embodiment one

As shown in FIG. 1 , the first embodiment of the present invention provides an LED epitaxial wafer for regulating quantum well carbon impurities, including a substrate 1 and a first semiconductor layer and an active layer 5 sequentially deposited on the substrate 1 and a second semiconductor layer;

As shown in FIG. 2 , the active layer 5 includes M composite quantum well layers 51 and quantum barrier layers 52 that are periodically and alternately arranged, and the composite quantum well layer 51 sequentially includes several stacked first A carbon impurity control layer 511, a quantum well layer 512, and a plurality of second carbon impurity control layers 513, the carbon impurity content of the first carbon impurity control layers 511 decreases along the epitaxial direction, and some of the second carbon impurity control layers 513 The carbon impurity content of the carbon impurity increases along the epitaxial direction, and the carbon impurity concentrations of the first carbon impurity regulation layer 511 and the second carbon impurity regulation layer 513 are both higher than the carbon impurity concentration of the quantum well layer 512 .

Specifically, the radius of the C impurity atoms in the quantum well of the present invention is close to that of Ga atoms or N atoms, so as to generate substitution atoms. At the same time, it can also prevent the InGaN lattice from being distorted when the impurity atoms become interstitial atoms, which will affect the InGaN material. The crystal quality of the compound quantum well layer 51 deposited includes the first carbon impurity control layer 511 and the second carbon impurity control layer 513, which are grown under low pressure conditions, and the high V/III ratio can effectively reduce the quantum well layer 512. C impurity content, improve the crystal quality of the quantum well layer, secondly, the first carbon impurity control layer 511 and the second carbon impurity control layer 513 can also reduce the donor level due to the formation of C instead of Ga sites, and the formation of C instead of N sites 1. Generating an acceptor energy level, resulting in a decrease in carrier concentration and an increase in non-radiative recombination efficiency. Finally, the C impurity concentration is modulated by the first carbon impurity control layer 511 and the second carbon impurity control layer 513 to reduce the polarization effect of the quantum well. Improve the overlap of hole wave functions generated by electrons and holes, and improve the luminous efficiency of LEDs.

In this embodiment, both the first carbon impurity control layer 511 and the second carbon impurity control layer 513 are one of a GaN layer, an AlGaN layer, an InGaN layer, and a BGaN layer.

In this embodiment, the carbon impurity concentration of the quantum well layer 512 is less than 1E17 atoms/cm ³ .

In this embodiment, the composite quantum well layer 51 has a thickness ranging from 1 nm to 10 nm.

In this embodiment, the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 ranges from 1:1:1 to 1:10:1 .

In this embodiment, the value range of the period M in which the composite quantum well layers 51 and the quantum barrier layers 52 are alternately arranged is: 1≤M≤20.

In this embodiment, the first semiconductor layer includes a buffer layer 2, an undoped GaN layer 3, and an N-type GaN layer 4 sequentially deposited on the substrate 1, and the second semiconductor layer includes a buffer layer deposited on the substrate 1 in sequence. The electron blocking layer 6 and the P-type GaN layer 7 on the active layer 5 .

In order to facilitate subsequent photoelectric tests and facilitate understanding, several experimental groups and control groups are introduced in this application.

Among them, the experimental groups include experimental group 1, experimental group 2, experimental group 3, experimental group 4, experimental group 5, experimental group 6, experimental group 7, experimental group 8, experimental group 9, experimental group 1, experimental group 2, experimental group Group three, experiment group four, experiment group five, experiment group six, experiment group seven, experiment group eight, and experiment group nine all adopted a kind of LED epitaxial wafer regulating quantum well carbon impurities as described in embodiment one, and all of them Including the active layer 5 as described in Embodiment 1, the control group uses LED epitaxial wafers in the prior art, and its structure is roughly the same as that of Embodiment 1, but the difference is as follows: the control group uses InGaN stacked alternately by M periods An active layer composed of a quantum well layer and an AlGaN quantum barrier layer, and M is 10, the thickness of the InGaN quantum well layer is 3.2nm, and the thickness of the AlGaN quantum barrier layer is 9.5nm;

Specifically, the thickness of the composite quantum well layer 51 in the experimental group one is 5 nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:3:1, the period M in which the composite quantum well layer 51 and the quantum barrier layer 52 are alternately arranged is 10, and the carbon impurity concentration of the quantum well layer 512 is 3.5E16 atoms/cm ³ ;

The thickness of the composite quantum well layer 51 in the experimental group two is 10nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:3 : 1, the period M of the alternate arrangement of the composite quantum well layer 51 and the quantum barrier layer 52 is 10, and the carbon impurity concentration of the quantum well layer 512 is 3.5E16 atoms/cm ³ ;

The thickness of the composite quantum well layer 51 in the experimental group three is 1 nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:3 : 1, the period M of the alternate arrangement of the composite quantum well layer 51 and the quantum barrier layer 52 is 10, and the carbon impurity concentration of the quantum well layer 512 is 3.5E16 atoms/cm ³ ;

The thickness of the composite quantum well layer 51 in the experimental group four is 5nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:10 : 1, the period M of the alternate arrangement of the composite quantum well layer 51 and the quantum barrier layer 52 is 10, and the carbon impurity concentration of the quantum well layer 512 is 3.5E16 atoms/cm ³ ;

The thickness of the composite quantum well layer 51 in the experimental group five is 5nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:1 : 1, the period M of the alternate arrangement of the composite quantum well layer 51 and the quantum barrier layer 52 is 10, and the carbon impurity concentration of the quantum well layer 512 is 3.5E16 atoms/cm ³ ;

The thickness of the composite quantum well layer 51 in experimental group six is 5 nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:3 : 1, the period M in which the composite quantum well layer 51 and the quantum barrier layer 52 are alternately arranged is 20, and the carbon impurity concentration of the quantum well layer 512 is 3.5E16 atoms/cm ³ ;

The thickness of the composite quantum well layer 51 in the experimental group seven is 5nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:3 : 1, the period M in which the composite quantum well layer 51 and the quantum barrier layer 52 are alternately arranged is 1, and the carbon impurity concentration of the quantum well layer 512 is 3.5E16 atoms/cm ³ ;

The thickness of the composite quantum well layer 51 in the experimental group eight is 5nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:3 : 1, the period M in which the composite quantum well layer 51 and the quantum barrier layer 52 are alternately arranged is 10, and the carbon impurity concentration of the quantum well layer 512 is 5.0E16 atoms/cm ³ ;

The thickness of the composite quantum well layer 51 in the experimental group nine is 5nm, and the thickness ratio between the first carbon impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is 1:3 : 1, the period M in which the composite quantum well layer 51 and the quantum barrier layer 52 are alternately arranged is 10, and the carbon impurity concentration of the quantum well layer 512 is 1.0E17 atoms/cm ³ ;

The LED epitaxial wafers in the above-mentioned several experimental groups and the control group with controlled quantum well carbon impurities were prepared into chips with a size of 10×24mil, and tested at a current of 120 mA/60 mA. The test results are shown in Table 1.

Table 1

The luminous efficiency of the LED epitaxial wafer provided by the control group is used as a benchmark, so its luminous efficiency is 0%, while the experimental group 1 has a 5% luminous effect compared with the control group, and the experimental group 2 is compared with the control group. The light efficiency increased by 2.5%. Compared with the control group, the light efficiency of the experimental group three increased by 1.6%. Compared with the control group, the light effect of the experimental group four increased by 3.2%. Compared with the control group, the light efficiency of the experimental group 6 increased by 3.1%, compared with the control group, the light efficiency of the experimental group 7 increased by 1.2%, and the light efficiency of the experimental group 8 increased by 1% compared with the control group. Compared with the control group, the light efficiency of the experimental group nine increased by 1.8%.

Therefore, it can be seen that compared with the control group, the high luminous efficiency LED epitaxial wafer provided by the experimental group 1 has the largest luminous efficiency improvement of 5%, and correspondingly, the thickness of the composite quantum well layer 51 is preferably 5 nm, and the first carbon The thickness ratio between the impurity control layer 511, the quantum well layer 512 and the second carbon impurity control layer 513 is preferably 1:3:1, and the composite quantum well layer 51 and the quantum barrier layer 52 are alternately arranged The period M of the cloth is preferably 10, and the carbon impurity concentration of the quantum well layer 512 is preferably 3.5E16 atoms/cm ³ .

It is worth noting that, in some other embodiments of the present invention, the following solution is also provided, an LED comprising the LED epitaxial wafer for controlling the carbon impurities in the quantum well as described in the first embodiment.

Embodiment two

As shown in Figure 3, the second embodiment of the present invention provides a method for preparing an LED epitaxial wafer that regulates quantum well carbon impurities, including the following steps:

S01, providing a substrate 1;

Wherein, the substrate 1 can be selected from one of a sapphire substrate, a SiO ₂ sapphire composite substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and a zinc oxide substrate;

Specifically, in this embodiment, the substrate 1 is selected from a sapphire substrate. Sapphire is currently the most commonly used GaN-based LED substrate material. good stability.

In this embodiment, Zhongwei A7 MOCVD (Metal-organic Chemical Vapor Deposition, MOCVD for short) equipment is used, high-purity H ₂ (hydrogen), high-purity N ₂ (nitrogen), high-purity H ₂ and high-purity One of the mixed gases of pure _N2 is used as carrier gas, high-purity _NH3 is used as N source, trimethylgallium (TMGa) and triethylgallium (TEGa) are used as gallium source, and trimethylindium (TMIn) is used as indium source, trimethylaluminum (TMAl) as aluminum source, silane (SiH ₄ ) as N-type dopant, and dimagnesium (CP ₂ Mg) as P-type dopant for epitaxial growth.

S02, depositing a first semiconductor layer on the substrate 1;

Wherein, a buffer layer 2 , a non-doped GaN layer 3 and an N-type GaN layer 4 are sequentially deposited on the substrate 1 to form the first semiconductor layer.

First, depositing a buffer layer 2 on the substrate 1;

Specifically, the buffer layer 2 is an AlN/GaN buffer layer. The buffer layer is deposited in PVD of applied materials, and its thickness is 15 nm. The AlN/GaN buffer layer provides nucleation centers with the same orientation as the substrate 1, releasing The stress caused by the lattice mismatch between GaN and the substrate 1 and the thermal stress caused by the mismatch of thermal expansion coefficients are eliminated, and further growth provides a flat nucleation surface, reducing the contact angle for nucleation and growth to allow island growth GaN crystal grains can be connected into planes in a small thickness and transformed into two-dimensional epitaxial growth.

Afterwards, the substrate 1 on which the buffer layer 2 has been deposited needs to be pretreated;

Specifically, transfer the substrate 1 that has been plated with the buffer layer 2 into MOCVD, perform pretreatment in _H2 atmosphere for 1min~10min, and treat the substrate 1 at a temperature of 1000°C~1200°C, and then perform nitriding treatment on the substrate 1 to improve the The crystal quality of the buffer layer 2 can be effectively improved, and the crystal quality of the subsequently deposited GaN epitaxial layer can be effectively improved.

Next, depositing a non-doped GaN layer 3 on the buffer layer 2;

Wherein, the growth temperature of the non-doped GaN layer 3 is 1050°C~1200°C, the pressure is 100torr~600torr, and the thickness is 1um~5um;

Specifically, the growth temperature of the non-doped GaN layer 3 is 1100° C., the growth pressure is 150 torr, and the growth thickness is 2 um to 3 um. The growth temperature of the non-doped GaN layer 3 is relatively high, and the pressure is low, and the quality of the prepared GaN crystal is better. At the same time, as the thickness of GaN increases, the compressive stress will be released through stacking faults, the line defects will be reduced, the crystal quality will be improved, and the reverse leakage will be reduced. However, increasing the GaN layer thickness consumes a lot of Ga source materials, which greatly improves the performance of LEDs. Epitaxial cost, so the current LED epitaxial wafer usually grows 2um~3um non-doped GaN layer 3, which not only saves production cost, but also has high crystal quality of GaN material.

Finally, an N-type GaN layer 4 is deposited on the non-doped GaN layer 3;

Among them, the growth temperature of the N-type GaN layer 4 is 1050°C~1200°C, the pressure is 100torr~600torr, the thickness is 2um~3um, and the Si doping concentration is 1E19 atoms/cm ³ ~5E19 atoms/cm ³ ;

Specifically, the growth temperature of the N-type GaN layer 4 is 1120°C, the growth pressure is 100torr, the growth thickness is 2um~3um, and the Si doping concentration is 2.5E19atoms/cm ³ . First, the N-type GaN layer 4 provides enough electrons for the LED to emit light. The resistivity of the N-type GaN layer 4 is higher than the resistivity of the transparent electrode on the P-GaN, so sufficient Si doping can effectively reduce the resistivity of the N-type GaN layer 4, and finally the N-type GaN layer 4 is sufficient The thickness can effectively release the luminous efficiency of the stress LED.

S03, alternately depositing M periods of composite quantum well layers 51 and quantum barrier layers 52 on the first semiconductor layer to form the active layer 5;

Wherein, the composite quantum well layer 51 includes stacked first carbon impurity control layers 511, quantum well layers 512, and second carbon impurity control layers 513 sequentially along the epitaxial direction, and several first carbon impurity control layers 511 The carbon impurity content of the second carbon impurity control layer 513 decreases along the epitaxial direction, and the carbon impurity content of the second carbon impurity control layer 513 increases along the epitaxial direction. The impurity concentrations are all higher than the carbon impurity concentrations of the quantum well layer 512;

Specifically, the first carbon impurity control layer 511 and the second carbon impurity control layer 513 are both GaN layers, AlGaN layers, InGaN layers, and BGaN layers, and the carbon impurity concentration of the quantum well layer 512 is less than 1E17 atoms/cm ³ , the thickness of the composite quantum well layer 51 is in the range of 1 nm to 10 nm, and the thickness between the first carbon impurity control layer 511 , the quantum well layer 512 and the second carbon impurity control layer 513 The thickness ratio ranges from 1:1:1 to 1:10:1, and the period M in which the composite quantum well layers 51 and the quantum barrier layers 52 are alternately arranged ranges from: 1≤M≤20.

At the same time, the growth temperature of the composite quantum well layer 51 is 700°C~1000°C, the ratio of N ₂ /NH ₃ in the growth atmosphere is 10:1~1:10, and the growth pressure is 50torr~300torr. The quantum barrier layer 52 is specifically AlGaN layer, the growth temperature ranges from 800°C to 1000°C, the thickness ranges from 1nm to 50nm, the growth pressure ranges from 50torr to 300torr, and the Al composition ranges from 0.05 to 0.5.

S04, depositing a second semiconductor layer on the quantum barrier layer 52 in the last period;

Wherein, the electron blocking layer 6 and the P-type GaN layer 7 are sequentially deposited on the quantum barrier layer 52 in the last period to form the second semiconductor layer.

First, an electron blocking layer 6 is deposited on the quantum barrier layer 52 of the last period;

Wherein, the electron blocking layer 6 is an AlInGaN layer with a thickness of 10nm~40nm, a growth temperature of 900°C~1000°C, and a pressure of 100torr~300torr, wherein the Al composition is 0.005<x<0.1, and the In composition concentration is 0.01<y<0.2;

Specifically, the electron blocking layer 6 has a thickness of 15 nm, wherein the concentration of the Al composition gradually changes from 0.01 to 0.05 in the growth direction of the epitaxial layer, the concentration of the In composition is 0.01, the growth temperature is 965°C, and the growth pressure is 200 torr, the electron blocking layer 6 can be effectively Limiting the overflow of electrons can also reduce the blocking of holes, improve the injection efficiency of holes into the quantum well, reduce the Auger recombination of carriers, and improve the luminous efficiency of LEDs.

Finally, depositing a P-type GaN layer 7 on the electron blocking layer 6;

Among them, the growth temperature of the P-type GaN layer 7 is 900°C~1050°C, the thickness is 10nm~50nm, the growth pressure is 100torr~600torr, and the Mg doping concentration is 1E19atoms/cm ³ ~1E21atoms/cm ³ ;

Specifically, the growth temperature of the P-type GaN layer 7 is 985°C, the thickness is 15 nm, the growth pressure is 200 torr, and the Mg doping concentration is 2E20 atoms/cm ³ . If the Mg doping concentration is too high, the crystal quality will be damaged, and if the doping concentration is low, the space Hole concentration. At the same time, for the LED structure with V-shaped pits, the higher growth temperature of the P-type GaN layer 7 is also conducive to merging the V-shaped pits to obtain an LED epitaxial wafer with a smooth surface.

In summary, the radius of the C impurity atoms in the quantum well of the present invention is close to that of Ga atoms or N atoms, so as to generate substitution atoms, and at the same time, it can also prevent the InGaN lattice from being distorted when the impurity atoms become interstitial atoms, which affects the InGaN material. The crystal quality of the deposited composite quantum well layer 51 includes the first carbon impurity control layer 511 and the second carbon impurity control layer 513, which are grown under low pressure conditions, and the high V/III ratio can effectively reduce the quantum well layer. The C impurity content improves the crystal quality of the quantum well layer 512. Secondly, the first carbon impurity control layer 511 and the second carbon impurity control layer 513 can also reduce the donor level due to the formation of C instead of Ga sites, and the formation of C instead of N sites. 1. Generating an acceptor energy level, resulting in a decrease in carrier concentration and an increase in non-radiative recombination efficiency. Finally, the C impurity concentration is modulated by the first carbon impurity control layer 511 and the second carbon impurity control layer 513 to reduce the polarization effect of the quantum well , improve the wave function overlap of electrons and holes, and improve the luminous efficiency of LED.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (7)

1. The LED epitaxial wafer for regulating and controlling the quantum well carbon impurities is characterized by comprising a substrate, and a first semiconductor layer, an active layer and a second semiconductor layer which are sequentially deposited on the substrate;

the active layer comprises M composite quantum well layers and quantum barrier layers which are periodically and alternately arranged, the composite quantum well layers sequentially comprise a plurality of first carbon impurity regulating layers, quantum well layers and a plurality of second carbon impurity regulating layers which are stacked along the epitaxial direction, the carbon impurity content of the first carbon impurity regulating layers decreases along the epitaxial direction, the carbon impurity content of the second carbon impurity regulating layers increases along the epitaxial direction, and the carbon impurity concentrations of the first carbon impurity regulating layers and the second carbon impurity regulating layers are higher than the carbon impurity concentration of the quantum well layers;

the carbon impurity concentration of the quantum well layer is less than 1E17atoms/cm ³ The thickness range of the composite quantum well layer is 1 nm-10 nm, and the thickness ratio of the first carbon impurity regulating layer to the second carbon impurity regulating layer is 1:1:1-1:10:1.

2. The LED epitaxial wafer of claim 1, wherein the thickness ratio between the first carbon impurity control layer, the quantum well layer and the second carbon impurity control layer is in the range of 1:1:1 to 1:10:1.

3. The LED epitaxial wafer of claim 1, wherein the period M of the alternating arrangement of the composite quantum well layers and the quantum barrier layers has a range of values: m is more than or equal to 1 and less than or equal to 20.

4. The preparation method of the LED epitaxial wafer for regulating and controlling the quantum well carbon impurities is characterized by comprising the following steps of:

providing a substrate;

depositing a first semiconductor layer on the substrate;

alternately depositing M periods of composite quantum well layers and quantum barrier layers on the first semiconductor layer to form an active layer;

depositing a second semiconductor layer on the quantum barrier layer of the last cycle;

the composite quantum well layer sequentially comprises a plurality of first carbon impurity regulating layers, a quantum well layer and a plurality of second carbon impurity regulating layers which are stacked along the epitaxial direction, wherein the carbon impurity content of the first carbon impurity regulating layers is gradually decreased along the epitaxial direction, the carbon impurity content of the second carbon impurity regulating layers is gradually increased along the epitaxial direction, and the carbon impurity concentrations of the first carbon impurity regulating layers and the second carbon impurity regulating layers are higher than those of the quantum well layer.

5. According to claimThe method for preparing the LED epitaxial wafer for regulating and controlling the carbon impurities of the quantum well according to claim 4, which is characterized in that the growth temperature range of the composite quantum well layer is 700-1000 ℃ and the growth atmosphere is N ₂ /NH ₃ The ratio range is 10:1-1:10, and the growth pressure range is 50-300 torr.

6. The method for preparing the LED epitaxial wafer for regulating and controlling carbon impurities of the quantum well according to claim 4, wherein the quantum barrier layer is specifically an AlGaN layer, the growth temperature range is 800-1000 ℃, the thickness range is 1-50 nm, the growth pressure range is 50-300 torr, and the Al component range is 0.05-0.5.

7. An LED, characterized by comprising an LED epitaxial wafer according to any one of claims 1 to 3 for controlling quantum well carbon impurities.

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