阅读说明：本技术 一种PGaN改善型LED外延结构及其制备方法 (PGaN improved LED epitaxial structure and preparation method thereof ) 是由 李国强 于 2021-08-04 设计创作，主要内容包括：本发明提供一种PGaN改善型LED外延结构及其制备方法,该外延结构按照从下往上的顺序包括依次相连的衬底、缓冲层、本征GaN层、N型GaN层、发光量子阱层和P型GaN层；其中,所述发光量子阱层包括多级循环排布的GaN势垒层和InGaN阱层,所述P型GaN层包括多级循环排布的GaN本征层或低掺金属层和高掺金属层。其制备方法是于H-(2)环境中,在所述衬底上依次生长缓冲层、本征GaN层、N型GaN层、发光量子阱层和P型GaN层。本发明能够有效解决LED外延结构中P型层因Mg高掺引起的晶体质量不佳,并减少有源层位错延伸上来的Pits,进而提升了LED产品的品质。(The invention provides a PGaN improved LED epitaxial structure and a preparation method thereof, wherein the epitaxial structure comprises a substrate, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a light emitting quantum well layer and a P-type GaN layer which are sequentially connected from bottom to top; the light emitting quantum well layer comprises a GaN barrier layer and an InGaN well layer which are circularly arranged in a multi-stage mode, and the P-type GaN layer comprises a GaN intrinsic layer or a low-doped metal layer and a high-doped metal layer which are circularly arranged in a multi-stage mode. The preparation method is as follows H 2 In the environment, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a light emitting quantum well layer and a P-type GaN layer are sequentially grown on the substrate. The invention can effectively solve the problem of poor crystal quality of a P-type layer in the LED epitaxial structure due to high Mg doping, and reduce the Pits on the staggered extension of the active layer, thereby improving the quality of LED products.)

1. A PGaN improved LED epitaxial structure is characterized in that: the light-emitting diode comprises a substrate, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a light-emitting quantum well layer and a P-type GaN layer which are sequentially connected in sequence from bottom to top; the light emitting quantum well layer comprises a GaN barrier layer and an InGaN well layer which are circularly arranged in a multi-stage mode, and the P-type GaN layer comprises a GaN intrinsic layer or a low-doped metal layer and a high-doped metal layer which are circularly arranged in a multi-stage mode.

2. The epitaxial structure of PGaN improved LED according to claim 1, wherein: the total thickness of the P-type GaN layer is 50-200 nm, the thicknesses of the GaN intrinsic layer or the low-doped metal layer and the high-doped metal layer in multi-stage circulation are gradually reduced, and the thickness of the GaN intrinsic layer or the low-doped metal layer in the same-stage GaN intrinsic layer or the low-doped metal layer and the high-doped metal layer is larger than that of the high-doped metal layer.

3. The epitaxial structure of PGaN-improved LED according to claim 1 or 2, wherein: the cycle period of the GaN intrinsic layer or the low-doped metal layer and the high-doped metal layer is 3-10.

4. The epitaxial structure of PGaN improved LED according to claim 3, wherein: the P-type doping source of the low-doped metal layer and the P-type doping source of the high-doped metal layer are Mg or Zn, the concentration of the P-type doping source in the low-doped metal layer is 5E 17-1E 18, and the concentration of the P-type doping source in the high-doped metal layer is 5E 18-1E 20.

5. The epitaxial structure of PGaN improved LED according to claim 1, wherein: and a P-type electron barrier layer is also arranged between the light-emitting quantum well layer and the P-type GaN layer.

6. The epitaxial structure of PGaN improved LED according to claim 5, wherein: the thickness of the P-type electronic barrier layer is 30-80 nm, the Mg doping concentration is 5E 18-3.5E 19, and the material is a single-layer lattice or a combined lattice of a plurality of the single-layer lattices or a superlattice of a plurality of the single-layer lattices or the combined lattice of a plurality of the single-layer lattices or the superlattice of a plurality of the super-layers.

7. The method for preparing the PGaN improved LED epitaxial structure of any one of claims 1 to 6, wherein the method comprises the following steps: the method comprises the following steps:

in H₂Growing a buffer layer on the substrate in an environment;

then growing an intrinsic GaN layer on the buffer layer;

continuing to grow an N-type GaN layer on the intrinsic GaN layer;

continuing to grow a light-emitting quantum well layer on the N-type GaN layer;

and continuing to grow a P-type GaN layer on the growth multi-period light-emitting layer.

8. The method according to claim 7, wherein the PGaN-modified LED epitaxial structure comprises: the growth conditions of the P-type GaN layer are as follows: the temperature is 850-950 ℃, and the pressure is 300-600 Torr.

9. The method for preparing the epitaxial structure of the PGaN-improved LED according to claim 7 or 8, wherein the method comprises the following steps: the preparation method further comprises the following steps: and growing a P-type electron blocking layer before growing the P-type GaN layer on the multi-period light-emitting layer.

10. The method according to claim 9, wherein the PGaN-modified LED epitaxial structure comprises: the growth conditions of the P-type electron blocking layer are as follows: the temperature 850 ℃ and 950 ℃, and the pressure 100 ℃ and 200 Torr.

Technical Field

The invention belongs to the technical field of semiconductor optoelectronic devices, and particularly relates to a PGaN improved LED epitaxial structure and a preparation method thereof.

Background

With the continuous development of the LED technology, the LED lamp has the advantages of high luminous efficiency, small light attenuation, energy conservation, environmental protection and the like, is applied more and more widely, and also puts higher and higher requirements on the LED, particularly on brightness and reliability; the growth difficulty of a P-type layer in the traditional epitaxial growth method of the LED is the greatest, the P-type layer needs to improve Mg doping efficiency and hole concentration, and the Pits extending from an active layer needs to be covered, the crystal quality of the P-type layer grown in the traditional high-low Mg doping superposition growth mode is not ideal, and meanwhile, the dislocation extending from the active layer cannot be bent and extinguished well, so that the hole injection efficiency of the P-type layer is reduced, and the luminous efficiency of the LED is reduced.

In view of the above, there is an urgent need to develop a new PGaN improved LED epitaxy technology to overcome the above-mentioned defects of the existing LED epitaxy technology.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a PGaN improved LED epitaxial structure and a preparation method thereof, and the technology can effectively solve the problem that the P-type layer has poor crystal quality due to high Mg doping, reduce the Pits on the staggered extension of the active layer and further improve the quality of LED products. The technical scheme of the invention is as follows:

in a first aspect, the invention provides a PGaN improved LED epitaxial structure, which includes, in order from bottom to top, a substrate, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a light emitting quantum well layer, and a P-type GaN layer, which are connected in sequence; the light emitting quantum well layer comprises a GaN barrier layer and an InGaN well layer which are circularly arranged in a multi-stage mode, and the P-type GaN layer comprises a GaN intrinsic layer or a low-doped metal layer and a high-doped metal layer which are circularly arranged in a multi-stage mode.

Optionally, the substrate is a material suitable for growth of iii-v semiconductor materials, such as sapphire, sapphire AlN thin film, GaN, silicon carbide, and the like.

Further, the thickness of the buffer layer is 300-1000 nm, and the buffer layer is made of one or more of GaN, AlGaN, InAlGaN and InGaN in a superlattice or alternate stacking mode.

Furthermore, the thickness of the intrinsic GaN layer is 1.0-2.0 um, and the intrinsic GaN layer is made of one or more of GaN, AlGaN, InAlGaN and InGaN and combined in a superlattice or alternate stacking mode.

Furthermore, the N-type GaN layer is silicon-doped GaN with the thickness of 1-4 um, and the doping concentration of Si is 1E 18-3E 19.

Furthermore, In the light-emitting quantum well layer, the thickness of the GaN barrier layer is 3.0-10.0 nm, the thickness of the InGaN well layer is 3.0-6.0 nm, and the mass percentage of In the light-emitting quantum well layer is 8% -20%.

Preferably, the cycle period of the GaN barrier layer and the InGaN well layer in the light emitting quantum well layer is 3-10.

Furthermore, the total thickness of the P-type GaN layer is 50-200 nm, the thicknesses of the GaN intrinsic layer or the low-doped metal layer and the high-doped metal layer in multi-stage circulation are gradually reduced, and the thickness of the GaN intrinsic layer or the low-doped metal layer at the same stage is larger than that of the high-doped metal layer.

Preferably, the thickness of the GaN intrinsic layer or the low-doped metal layer is 5-20nm, and the thickness of the high-doped metal layer is 3-15 nm.

Preferably, the cycle period of the GaN intrinsic layer or the low-doped metal layer and the high-doped metal layer is 3-10.

Preferably, the P-type doping source of the low-doped metal layer and the high-doped metal layer is Mg or Zn, the concentration of the P-type doping source in the low-doped metal layer is 5E 17-1E 18, and the concentration of the P-type doping source in the high-doped metal layer is 5E 18-1E 20.

Optionally, a P-type electron blocking layer is further arranged between the light-emitting quantum well layer and the P-type GaN layer.

Further, the thickness of the P-type electron blocking layer is 30-80 nm, the Mg doping concentration is 5E 18-3.5E 19, and the material is a single-layer lattice of one of pAlGaN, pAlInGaN and pInGaN, or a combination lattice of several of the pAlGaN, the pAlInGaN and the pInGaN, or a superlattice of several of the pAlGaN, the pAlInGaN and the pInGaN.

In a second aspect, the present invention provides a method for preparing the PGaN-improved LED epitaxial structure, including the following steps:

in H₂Growing a buffer layer on the substrate in an environment;

then growing an intrinsic GaN layer on the buffer layer;

continuing to grow an N-type GaN layer on the intrinsic GaN layer;

continuing to grow a light-emitting quantum well layer on the N-type GaN layer;

and continuing to grow a P-type GaN layer on the growth multi-period light-emitting layer.

Further, the growth conditions of the buffer layer are as follows: the temperature is 800-1050 ℃, and the pressure is 100-.

Further, the growth conditions of the intrinsic GaN layer and the N-type GaN layer are: the temperature is 1000-1200 ℃, and the pressure is 100-.

Further, the growth conditions of the light emitting quantum well layer are as follows: the temperature is 700-900 ℃, and the pressure is 200 ℃ and 400 Torr.

Further, the growth conditions of the P-type GaN layer are as follows: the temperature is 850-950 ℃, and the pressure is 300-600 Torr.

Further, the preparation method further comprises the following steps: growing a P-type electronic barrier layer before growing a P-type GaN layer on the light-emitting quantum well layer, wherein the growth conditions of the barrier layer are as follows: the temperature 850 ℃ and 950 ℃, and the pressure 100 ℃ and 200 Torr.

The invention has the beneficial effects that: the invention provides a novel PGaN improved LED epitaxial structure and a preparation method thereof, and the technology can effectively solve the problem of poor crystal quality of a P-type layer in the LED epitaxial structure due to high Mg doping, solve the problems of Pits extending from dislocation of an active layer and further improve the quality of an LED product.

Drawings

Fig. 1 is a structural formation process diagram of the PGaN improved LED epitaxial structure of the present invention, in which a 1-substrate, a 2-buffer layer, a 3-intrinsic GaN layer, a 4-N type GaN layer, a 5-luminescent quantum well layer, a 6-P type electron blocking layer, and a 7-P type GaN layer.

Detailed Description

In the description of the present invention, it is to be noted that those whose specific conditions are not specified in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturers. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The present invention will now be described in further detail with reference to the following figures and specific examples, which are intended to be illustrative, but not limiting, of the invention.

Example 1

Referring to fig. 1, the present embodiment provides a PGaN improved LED epitaxial structure and a method for manufacturing the same, where the epitaxial structure includes, in order from bottom to top, a silicon substrate, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a luminescent quantum well layer, a P-type electron blocking layer, and a P-type GaN layer, which are connected in sequence; the light emitting quantum well layer comprises a GaN barrier layer and an InGaN well layer which are circularly arranged in a multi-stage mode, and the P-type GaN layer comprises a low-doped metal layer and a high-doped metal layer which are circularly arranged in a multi-stage mode.

In this embodiment, the buffer layer has a thickness of 600nm and is made of GaN.

In this embodiment, the intrinsic GaN layer has a thickness of 1.5um and is made of GaN.

In the present embodiment, the N-type GaN layer is Si-doped GaN with a thickness of 2um, wherein the Si doping concentration is 1e 19.

In this example, the thickness of the GaN barrier layer In the luminescent quantum well layer was 5nm, and the thickness of the InGaN well layer was 3nm, In which the mass percentage content In the luminescent quantum well layer was 12%. The cycle period of the GaN barrier layer and the InGaN well layer was 7.

In the embodiment, the thickness of the P-type electron blocking layer is 50nm, the doping concentration of Mg is 1E19, and the material is pAlGaN.

In this embodiment, the thicknesses of the low-doped PGaN layer (i.e., the low-doped metal layer) and the high-doped PGaN layer (i.e., the high-doped metal layer) in the P-type GaN layer in the multi-stage cycle are both gradually decreased by 2nm, and the former thickness is greater than the latter thickness in the same stage of the low-doped layer and the high-doped PGaN layer. The thickness of the first-level low-doped PGaN layer is 15nm, the thickness of the first-level low-doped PGaN layer is 10nm, and the cycle period is 3.

In this embodiment, the low-doped and high-doped P-type GaN doping source is Mg, and has a concentration of 7E17 in the low-doped layer and a concentration of 1E19 in the high-doped layer.

The preparation method of the PGaN improved LED epitaxial structure comprises the following steps:

(1) in H₂Growing a buffer layer on the substrate in an environment, wherein the growth temperature is 900 ℃, and the pressure is 200 Torr;

(2) then growing an intrinsic GaN layer on the buffer layer, wherein the growth temperature is 1100 ℃, and the pressure is 200 Torr;

(3) continuously growing an N-type GaN layer on the intrinsic GaN layer, wherein the growth temperature is 1050 ℃, and the pressure is 200 Torr;

(4) continuously growing a luminescent quantum well layer on the N-type GaN layer, wherein the growth temperature is 800 ℃, and the pressure is 200 Torr;

(5) continuously growing a P-type electron barrier layer on the light-emitting quantum well layer, wherein the growth temperature is 890 ℃, and the pressure is 100 Torr;

(6) and continuously growing a P-type GaN layer on the P-type electron blocking layer, wherein the growth temperature is 900 ℃, and the pressure is 450 Torr.

33 × 33COW data: the brightness is 521mW @453.7nm, the IR yield and the ESD yield are 95.5 percent and 99 percent respectively, and the electric property is good. As shown in table 1.

TABLE 1

Example 2

Referring to fig. 1, the present embodiment provides a PGaN improved LED epitaxial structure and a method for manufacturing the same, where the epitaxial structure includes, in order from bottom to top, a silicon substrate, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a luminescent quantum well layer, a P-type electron blocking layer, and a P-type GaN layer, which are connected in sequence; the light emitting quantum well layer comprises a GaN barrier layer and an InGaN well layer which are circularly arranged in a multi-stage mode, and the P-type GaN layer comprises a GaN intrinsic layer and a highly-doped metal layer which are circularly arranged in a multi-stage mode.

In this embodiment, the buffer layer has a thickness of 300nm and is made of GaN.

In this embodiment, the intrinsic GaN layer has a thickness of 1.0um and is made of GaN.

In the present embodiment, the N-type GaN layer is Si-doped N-type GaN with a thickness of 4um, wherein the Si doping concentration is 3e 19.

In the present embodiment, In the light emitting quantum well layer, the thickness of the GaN barrier layer was 5nm, and the thickness of the InGaN well layer was 3nm, In which the mass percentage content In the light emitting quantum well layer was 12%. The cycle period of the GaN barrier layer and the InGaN well layer was 7.

In the embodiment, the thickness of the P-type electron blocking layer is 80nm, the doping concentration of Mg is 3.5E19, and the material is pAlInGaN.

In the embodiment, the thicknesses of the GaN intrinsic layer and the highly doped metal layer of the multi-stage circulation are gradually reduced by 1nm, and the thickness of the GaN intrinsic layer is larger than that of the highly doped metal layer in the same stage. The thickness of the first-stage GaN intrinsic layer is 10nm, the thickness of the first-stage highly-doped metal layer is 5nm, and the cycle period is 5.

In this embodiment, the P-type doping source of the GaN intrinsic layer and the highly doped metal layer is Mg, wherein the concentration of the GaN intrinsic layer is 5E17, and the concentration of the highly doped metal layer is 5E 18.

The preparation method of the PGaN improved LED epitaxial structure comprises the following steps:

(1) in H₂Growing a buffer layer on the substrate in an environment, wherein the growth temperature is 1050 ℃, and the pressure is 200 Torr;

(2) then growing an intrinsic GaN layer on the buffer layer, wherein the growth temperature is 1200 ℃, and the pressure is 200 Torr;

(3) continuously growing an N-type GaN layer on the intrinsic GaN layer, wherein the growth temperature is 1000 ℃, and the pressure is 200 Torr;

(4) continuously growing a luminescent quantum well layer on the N-type GaN layer, wherein the growth temperature is 700 ℃, and the pressure is 200 Torr;

(5) continuously growing a P-type electronic barrier layer on the light-emitting quantum well layer, wherein the growth temperature is 900 ℃ and the pressure is 100 Torr;

(6) and continuously growing a P-type GaN layer on the P-type electron blocking layer, wherein the growth temperature is 950 ℃, and the pressure is 400 Torr.

33 × 33COW data: the brightness is 528mW @455.8nm, the IR yield and the ESD yield are 97.8 percent and 100 percent respectively, and the electric property is good. As shown in table 2.

TABLE 2

	Plate type	Wavelength nm	Brightness mW	IR yield	ESD yield
						Example 2	33*33	455.85	528.32	97.82％	100％

Comparative example 1

The present comparative example provides a PGaN-improved LED epitaxial structure and a method for manufacturing the same, and the difference from example 1 is that: in the P-type GaN layer, the total thickness of the layer was 76nm, and the cycle number was 2.

Comparative example 2

The present comparative example provides a PGaN-improved LED epitaxial structure and a method for manufacturing the same, and the difference from example 2 is that: the GaN intrinsic layer is equal in thickness and high doped layer thickness, and the cycle number is 6.

Comparative example 3

The present comparative example provides a PGaN-improved LED epitaxial structure and a method for manufacturing the same, and the difference from example 1 is that: PGaN is a traditional low-admixture high-admixture structure, and the thicknesses of the PGaN and the PGaN are respectively 30nm and 25 nm. Comparative example data are summarized in table 3:

TABLE 3

	Plate type	Wavelength nm	Brightness mW	IR yield	ESD yield
						Example 1	33*33	453.75	521.15	95.49％	99％
Example 2	33*33	455.85	528.32	97.82％	100％
						Comparative example 1	33*33	453.41	520.37	91.62％	99％
Comparative example 2	33*33	454.88	523.69	91.47％	98％
						Comparative example 3	33*33	454.26	513.42	90.74％	96％

In summary, the invention provides a novel PGaN improved LED epitaxial structure and a method for manufacturing the same, which can effectively solve the problem of poor crystal quality of a P-type layer in the LED epitaxial structure due to high Mg doping, reduce Pits from the staggered extension of an active layer, and further improve the quality of LED products.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.