Sapphire substrate, light emitting diode chip, and method of manufacturing a substrate

Abstract

The present disclosure provides a sapphire substrate, a light emitting diode chip and a preparation method of the substrate, and belongs to the technical field of optoelectronic manufacturing. The sapphire substrate has a certain positioning straight edge on one side for epitaxial growth, and the side for epitaxial growth has a plurality of blind holes, and the cross-sectional area of the plurality of blind holes gradually increases in the direction away from the positioning straight edge. The present disclosure can improve the phenomenon of temperature non-uniformity on the sapphire substrate caused by centrifugal force and improve the consistency of the wavelength of the epitaxial wafer.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of optoelectronic manufacturing, and particularly relates to a sapphire substrate, a light emitting diode chip and a substrate preparation method. BACKGROUND

[0002] As a new product in the optoelectronic industry, a light emitting diode (LED) has the characteristics of small size, long service life, rich color, low energy consumption, etc., and is widely used in lighting, display screen, signal lamp, backlight, toy and other fields. The core structure of the LED is an epitaxial wafer, and the production of the epitaxial wafer has a great influence on the photoelectric properties of the LED.

[0003] In the related art, when growing an epitaxial wafer, a sapphire substrate is first placed in a groove of a graphite disc in a reaction cavity of a metal organic chemical vapor deposition (MOCVD) device. Then, the sapphire substrate in the graphite disc is heated by a heating wire in the MOCVD device, and raw materials are introduced into the reaction cavity to epitaxially grow an epitaxial wafer on the sapphire substrate.

[0004] In the epitaxial growth process, the graphite disc rotates at a high speed. Due to the centrifugal force, the area of the sapphire substrate close to the center of the graphite disc is raised, so that the temperature of the raised area is lower, and the wavelength of the epitaxial wafer grown on the raised area is longer, thereby causing poor wavelength consistency of the epitaxial wafer. SUMMARY

[0005] The present disclosure provides a sapphire substrate, a light emitting diode chip and a substrate preparation method, which can improve the phenomenon of uneven temperature on the sapphire substrate caused by centrifugal force and improve the wavelength consistency of the epitaxial wafer. The technical solution is as follows:

[0006] In a first aspect, the present disclosure provides a sapphire substrate, one side of the sapphire substrate for epitaxial growth has a positioning straight edge, and the side for epitaxial growth has a plurality of blind holes, the cross-sectional areas of the plurality of blind holes gradually increase in a direction away from the positioning straight edge.

[0007] In an implementation manner of the present disclosure, the side for epitaxial growth has a plurality of partitions, and the plurality of partitions are arranged in sequence from the positioning straight edge to the direction away from the positioning straight edge; the cross-sectional areas of the blind holes in the same partition are the same, and the cross-sectional areas of the blind holes in each partition gradually increase from the positioning straight edge to the direction away from the positioning straight edge.

[0008] In another implementation manner of the embodiment of the present disclosure, the same partition includes at least one row of multiple blind holes arranged at intervals, and centers of the blind holes in the same row are located on the same circular arc line.

[0009] In another implementation manner of the embodiment of the present disclosure, the blind hole includes a counterbore section and a tapered hole section connected in sequence, one end of the counterbore section is connected coaxially with a small end of the tapered hole section, and a large end of the tapered hole section is located on the surface for epitaxial growth; the counterbore sections of the multiple blind holes have the same aperture, and the diameter of the large end of the tapered hole section gradually increases from the positioning straight edge to a direction away from the positioning straight edge.

[0010] In another implementation manner of the embodiment of the present disclosure, the aperture of the counterbore section is 100 nm to 600 nm, and the length of the counterbore section is 100 nm to 500 nm in a direction perpendicular to the surface for epitaxial growth.

[0011] In another implementation manner of the embodiment of the present disclosure, the length of the tapered hole section is 100 nm to 500 nm, the diameter of the large end of the tapered hole section is 800 nm to 1200 nm, and the diameter of the small end of the tapered hole section is 500 nm to 700 nm.

[0012] In another implementation manner of the embodiment of the present disclosure, the spacing between two adjacent blind holes is 800 nm to 1500 nm.

[0013] In a second aspect, the embodiment of the present disclosure provides a preparation method of a sapphire substrate, and the preparation method comprises:

[0014] providing a sapphire substrate;

[0015] forming multiple blind holes on a surface of the sapphire substrate for epitaxial growth, the surface for epitaxial growth has a positioning straight edge, and the multiple blind holes gradually increase in cross-sectional area in a direction away from the positioning straight edge.

[0016] In another implementation manner of the embodiment of the present disclosure, the forming multiple blind holes on the surface of the sapphire substrate for epitaxial growth comprises: etching the surface of the sapphire substrate for epitaxial growth to form a blind hole, the blind hole has a counterbore section and a tapered hole section connected in sequence, one end of the counterbore section is connected coaxially with a small end of the tapered hole section, and a large end of the tapered hole section is located on the surface for epitaxial growth.

[0017] In a third aspect, the embodiment of the present disclosure provides a light emitting diode chip, and the light emitting diode chip comprises the sapphire substrate as described above.

[0018] The technical solution provided by the embodiment of the present disclosure has at least the following beneficial effects:

[0019] The embodiment of the present disclosure provides a sapphire substrate for epitaxial growth, one side of which is provided with a plurality of spaced blind holes, and the side for epitaxial growth has a positioning straight edge. The cross-sectional area of each blind hole gradually increases from the positioning straight edge to a direction away from the positioning straight edge. Since the positioning straight edge is towards the center of the graphite disc when the sapphire substrate is mounted on the graphite disc, the cross-sectional area of the blind hole on each sapphire substrate gradually increases from the positioning straight edge to a direction away from the center of the graphite disc. During epitaxial growth, the larger the cross-sectional area of the blind hole, the larger the volume of the air column formed in the epitaxial growth AlN template layer. Since the heat conduction capacity of air is much weaker than that of AlN material, the heat conduction capacity gradually weakens from the positioning straight edge to a direction away from the center of the graphite disc, thereby compensating for the phenomenon of uneven temperature on the sapphire substrate caused by centrifugal force and improving the consistency of the wavelength of the epitaxial wafer. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 is a structural schematic diagram of a sapphire substrate provided by the embodiment of the present disclosure;

[0022] Figure 2 is a top view of a sapphire substrate provided by the embodiment of the present disclosure;

[0023] Figure 3 is a flowchart of a preparation method of a sapphire substrate provided by the embodiment of the present disclosure;

[0024] Figure 4 is a structural schematic diagram of a light emitting diode chip provided by the embodiment of the present disclosure.

[0025] The various marks in the drawings represent the following:

[0026] 10, sapphire substrate; 11, positioning straight edge;

[0027] 20, blind hole; 210, counterbore section; 220, taper hole section;

[0028] 30, partition;

[0029] 41, low-temperature AlN layer; 42, high-temperature AlN layer; 43, n-type AlGaN layer; 44, multi-quantum well layer; 45, p-type AlGaN barrier layer; 46, p-type AlGaN layer; 47, p-type GaN layer. DETAILED DESCRIPTION

[0030] The purposes, technical solutions and advantages of the present disclosure will be more clearly understood from the following detailed description of the embodiments of the present disclosure taken in conjunction with the accompanying drawings.

[0031] Unless otherwise defined, technical terms or scientific terms used herein should be interpreted as is normally used by one of ordinary skill in the art to which the present disclosure pertains. The terms "first", "second", "third" and the like used in the description and the claims of the present disclosure do not necessarily mean any order, number or importance, but are used to distinguish different components. Similarly, the terms "one" or "a" or the like do not mean a quantity restriction, but mean that there is at least one. The terms "include" or "contain" or the like mean that the components or objects appearing before the terms "include" or "contain" cover the components or objects listed after the terms "include" or "contain" and their equivalents, and do not exclude other components or objects. The terms "connect" or "connected" or the like are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", "top", "bottom" and the like are only used to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships may also be changed accordingly.

[0032] Figure 1 is a structural schematic diagram of a sapphire substrate provided by an embodiment of the present disclosure, Figure 2 is a top view of a sapphire substrate provided by an embodiment of the present disclosure. As shown in Figure 1 , 2 , the sapphire substrate 10 has a positioning straight edge 11 on the side for epitaxial growth, and a plurality of blind holes 20 on the side for epitaxial growth. The cross-sectional area of the blind holes 20 gradually increases in the direction away from the positioning straight edge 11.

[0033] The embodiment of the present disclosure provides a sapphire substrate for epitaxial growth, one side of the sapphire substrate is provided with a plurality of spaced blind holes 20, and the side for epitaxial growth has a positioning straight edge 11. The cross-sectional area of each blind hole 20 gradually increases from the positioning straight edge 11 to a direction away from the positioning straight edge 11. Since the positioning straight edge 11 is towards the center of the graphite disc when the sapphire substrate is installed on the graphite disc, the cross-sectional area of the blind hole 20 on each sapphire substrate gradually increases from the positioning straight edge 11 to a direction away from the center of the graphite disc. During epitaxial growth, the larger the cross-sectional area of the blind hole 20, the larger the air column formed in the epitaxial growth AlN template layer, and since the heat conduction capacity of air is much weaker than that of AlN material, the heat conduction capacity gradually decreases from the positioning straight edge 11 to a direction away from the center of the graphite disc, thereby compensating for the phenomenon of temperature non-uniformity on the sapphire substrate caused by centrifugal force and improving the consistency of the wavelength of the epitaxial wafer.

[0034] Optionally, as shown in Figure 2 the side for epitaxial growth has a plurality of partitions 30, and the plurality of partitions 30 are arranged in sequence from the positioning straight edge 11 to a direction away from the positioning straight edge 11.

[0035] The cross-sectional area of the blind hole 20 in the same partition 30 is the same, and the cross-sectional area of the blind hole 20 in each partition 30 gradually increases from the positioning straight edge 11 to a direction away from the positioning straight edge 11.

[0036] By arranging the plurality of partitions 30 in a direction away from the positioning straight edge 11 and setting the cross-sectional area of the blind hole 20 in the same partition 30 to be the same, the heat conduction capacity of the area in the same partition 30 on the substrate body is kept consistent. Since the plurality of partitions 30 are arranged in sequence in a direction away from the positioning straight edge 11, the plurality of partitions 30 can form a plurality of areas with gradually changing heat conduction capacity on the substrate body, and the cross-sectional area of the blind hole 20 in the partition 30 farther away from the positioning straight edge 11 is larger, so that the phenomenon of temperature non-uniformity on the sapphire substrate caused by centrifugal force can be compensated for, and the consistency of the wavelength of the epitaxial wafer can be improved.

[0037] In the embodiment of the present disclosure, by arranging the plurality of partitions 30 and setting the cross-sectional area of the blind hole 20 in the plurality of partitions 30 to be the same and the cross-sectional area of the blind hole 20 in different partitions 30 to be different, the cross-sectional area of the blind hole 20 to be etched and formed on the substrate body can be quickly and conveniently determined, and the preparation efficiency can be improved.

[0038] Optionally, as shown in Figure 2 the same partition 30 includes at least one row of spaced blind holes 20, and the centers of the blind holes 20 in the same row are located on the same circular arc line.

[0039] The positioning straight edge 11 is located towards the center of the graphite disc, and the perpendicular bisector of the positioning straight edge 11 coincides with the diameter of the graphite disc.

[0040] The blind holes 20 in each sub-area 30 are arranged to be spaced along an arcuate line, so that the blind holes 20 in each sub-area 30 jointly form a fan ring shape. Since the blind holes in each hole group in the same sub-area 30 are distributed around the center of the arcuate line, the cross-sectional area of the blind holes 20 changes uniformly along the direction away from the center of the graphite disc, and the heat conduction capacity also changes uniformly along the direction away from the center of the graphite disc, so as to improve the phenomenon of temperature non-uniformity on the sapphire substrate caused by centrifugal force.

[0041] As shown in the example, Figure 2 The side of the sapphire substrate 10 for epitaxial growth has four fan-shaped sub-areas 30, which are arranged in sequence from the positioning straight edge 11 to the direction away from the positioning straight edge 11.

[0042] By arranging the four fan-shaped sub-areas 30 in the direction away from the positioning straight edge 11, and arranging the cross-sectional areas of the blind holes 20 in the same fan-shaped sub-area 30 to be the same, the heat conduction capacity of the area on the sapphire substrate 10 in the same fan-shaped sub-area 30 is kept consistent. Since the four fan-shaped sub-areas 30 are arranged in sequence in the direction away from the positioning straight edge 11, four areas with gradually changing heat conduction capacities are formed on the substrate body, and the cross-sectional area of the blind holes 20 in the fan-shaped sub-area 30 farther away from the positioning straight edge 11 is larger, so as to compensate for the phenomenon of temperature non-uniformity on the sapphire substrate caused by centrifugal force.

[0043] Optionally, as shown in the example, Figure 1 Each blind hole 20 includes a counterbore section 210 and a tapered hole section 220, one end of the counterbore section 210 is coaxially connected to the small end of the tapered hole section 220, and the large end of the tapered hole section 220 is located on the side for epitaxial growth.

[0044] In the embodiment of the present disclosure, each blind hole 20 includes a counterbore section 210 and a tapered hole section 220, one end of the counterbore section 210 is connected to the small end of the tapered hole section 220, and the large end of the tapered hole section 220 is located on the surface of the sapphire substrate 10. In this way, a plurality of tapered curved surfaces are formed on the surface of the sapphire substrate 10, which is conducive to reducing the dislocation density of the nitride film epitaxially grown on the sapphire substrate 10, so as to improve the crystal quality of the nitride film.

[0045] The diameters of the counterbore sections 210 of the plurality of blind holes 20 are the same, and the diameters of the large ends of the tapered hole sections 220 gradually increase from the positioning straight edge 11 to the direction away from the positioning straight edge 11. When adjusting the diameter of the blind hole 20, the diameter of the tapered hole section 220 is changed without changing the diameter of the counterbore section 210, that is, the diameter of the blind hole 20 does not need to be adjusted as a whole, so as to facilitate the rapid formation of the blind hole 20.

[0046] Exemplarily, the counterbore section 210 is a circular hole, and the tapered hole section 220 is a circular tapered hole.

[0047] Optionally, as shown in Figure 1 the counterbore section 210 has a hole diameter of 100 nm to 600 nm, and a length of 100 nm to 500 nm in a direction perpendicular to the surface for epitaxial growth.

[0048] Exemplarily, the counterbore section 210 has a hole diameter of 400 nm, and a length of 300 nm. By setting the counterbore section 210 to this size, it can be ensured that a large enough air column can be formed in the blind hole 20 to achieve the purpose of changing the heat conduction capacity.

[0049] Optionally, as shown in Figure 1 the tapered hole section 220 has a length of 100 nm to 500 nm, a large end of the tapered hole section 220 has a diameter of 800 nm to 1200 nm, and a small end of the tapered hole section 220 has a diameter of 500 nm to 700 nm.

[0050] Exemplarily, the tapered hole section 220 has a length of 400 nm, a small end of the tapered hole section 220 has a diameter of 400 nm, and a large end of the tapered hole section 220 has a diameter of 600 nm. By setting the tapered hole section 220 to this size, a suitable tapered curved surface is formed on the surface of the sapphire substrate 10, which is conducive to reducing the dislocation density of the nitride film epitaxially grown on the sapphire substrate 10, thereby improving the crystal quality of the nitride film.

[0051] In the embodiments of the present disclosure, the blind holes 20 located on the surface of the sapphire substrate 10 are uniformly distributed and cover the surfaces of the sapphire substrate 10 everywhere, so that the air columns formed can be distributed in each region on the surface of the sapphire substrate 10 to achieve the purpose of changing the heat conduction capacity.

[0052] Exemplarily, as shown in Figure 2 the same partition 30, each blind hole 20 is distributed around the surface of the sapphire substrate 10 with the same center as the circle point. Among them, the spacing between adjacent two blind holes 20 is 800 nm to 1500 nm.

[0053] As an example, the spacing between adjacent two blind holes 20 is 800 nm.

[0054] It should be noted that the blind holes 20 can also be arranged on the surface of the sapphire substrate 10 in other ways as long as the blind holes 20 are uniformly distributed, and the embodiments of the present disclosure are not limited.

[0055] Figure 3 is a flowchart of a preparation method of a sapphire substrate provided by the embodiments of the present disclosure. As shown in Figure 3 the preparation method comprises:

[0056] Step S11: providing a sapphire substrate.

[0057] Step S12: forming a plurality of blind holes on a surface of the sapphire substrate for epitaxial growth.

[0058] The surface for epitaxial growth has a positioning straight edge 11, and the plurality of blind holes 20 gradually increase in cross-sectional area in a direction away from the positioning straight edge 11.

[0059] The surface for epitaxial growth of the sapphire substrate 10 prepared by the preparation method is provided with a plurality of spaced blind holes 20, and the surface for epitaxial growth has a positioning straight edge 11. On the surface of the sapphire substrate 10, the cross-sectional area of each blind hole 20 gradually increases from the positioning straight edge 11 to a direction away from the positioning straight edge 11. Since the positioning straight edge 11 is directed to the center of the graphite disc when the sapphire substrate is installed on the graphite disc, the cross-sectional area of the blind hole 20 on each sapphire substrate gradually increases from the positioning straight edge 11 to a direction away from the center of the graphite disc. During epitaxial growth, the larger the cross-sectional area of the blind hole 20, the larger the volume of the air column formed in the epitaxial growth AlN template layer. Since the thermal conductivity of air is much weaker than that of AlN material, the thermal conductivity gradually weakens from the positioning straight edge 11 to a direction away from the center of the graphite disc, thereby compensating for the phenomenon of uneven temperature on the sapphire substrate caused by centrifugal force and improving the consistency of the wavelength of the epitaxial wafer.

[0060] Optionally, the sapphire substrate 10 is a flat sheet structure prepared from sapphire material.

[0061] In step S11, the sapphire substrate 10 can be pretreated, and the sapphire substrate 10 is placed in the MOCVD reaction chamber for baking treatment for 12 to 18 minutes. As an example, in the embodiment of the present disclosure, the sapphire substrate 10 is baked for 15 minutes.

[0062] Specifically, the baking temperature can be 1000-1200°C, and the pressure in the MOCVD reaction chamber during baking can be 100-200 mbar.

[0063] In step S12, the process of forming blind holes 20 on the surface of the sapphire substrate 10 can include etching the surface of the sapphire substrate for epitaxial growth to form blind holes, the blind holes having a connected counterbore section and a tapered hole section, one end of the counterbore section being coaxially connected to the small end of the tapered hole section, and the large end of the tapered hole section being located on the surface for epitaxial growth.

[0064] Specifically, first, an initial hole is formed on the surface of the sapphire substrate 10 by dry etching, and the length of the initial hole is the sum of the length of the hole section 210 and the length of the tapered hole section 220.

[0065] Then, the initial hole is continuously etched by dry etching to form the tapered hole section 220, so that the etched initial hole forms the hole section 210, and the preparation of the blind hole 20 is completed.

[0066] The hole section 210 is a circular hole, and the tapered hole section 220 is a conical hole.

[0067] Optionally, as shown in the figure, Figure 1 The diameter of the hole section 210 is 100-600 nm, and the length of the hole section 210 is 100-500 nm.

[0068] For example, the diameter of the hole section 210 is 400 nm, and the length of the hole section 210 is 300 nm. By setting the hole section 210 to this size, a large enough air column can be formed in the blind hole 20 to achieve the purpose of changing the heat conduction capacity.

[0069] Optionally, as shown in the figure, Figure 1 The length of the tapered hole section 220 is 100-500 nm, the diameter of the large end of the tapered hole section 220 is 800-1200 nm, and the diameter of the small end of the tapered hole section 220 is 500-700 nm.

[0070] For example, the length of the tapered hole section 220 is 400 nm, the diameter of the small end of the tapered hole section 220 is 400 nm, and the diameter of the large end of the tapered hole section 220 is 600 nm. By setting the tapered hole section 220 to this size, a suitable tapered surface is formed on the surface of the sapphire substrate 10, which is conducive to reducing the dislocation density of the nitride film epitaxially grown on the sapphire substrate 10, thereby improving the crystal quality of the nitride film.

[0071] Optionally, as shown in the figure, Figure 2 The side of the sapphire substrate 10 for epitaxial growth has a plurality of partitions 30, and the plurality of partitions 30 are arranged in sequence from the positioning straight edge 11 to the direction away from the positioning straight edge 11. The hole diameters of the blind holes 20 in the same partition 30 are the same, and the hole diameters of the blind holes 20 in each partition 30 gradually increase from the positioning straight edge 11 to the direction away from the positioning straight edge 11.

[0072] In the embodiments of the present disclosure, by setting the plurality of partitions 30 and setting the hole diameters of the blind holes 20 in the plurality of partitions 30 to be the same and the hole diameters of the blind holes 20 in different partitions 30 to be different, it is convenient and fast to determine the hole diameters of the blind holes 20 that need to be etched on the substrate body, thereby facilitating the improvement of the preparation efficiency.

[0073] In step S12, when the blind holes 20 are formed on the surface of the sapphire substrate 10, the blind holes 20 can be formed in batches according to the partitions 30 on the sapphire substrate 10.

[0074] In the same partition 30, the hole diameters of the counterbore sections 210 of the blind holes 20 are the same, and the diameters of the large ends of the taper hole sections 220 gradually increase from the positioning straight edge 11 to the direction away from the positioning straight edge 11.

[0075] When the hole diameters of the blind holes 20 are adjusted, the hole diameters of the taper hole sections 220 are changed without changing the hole diameters of the counterbore sections 210, i.e., the hole diameters of the blind holes 20 are not adjusted as a whole, so that the blind holes 20 can be quickly formed.

[0076] Optionally, as shown in Figure 2 , the same partition 30 includes at least one row of multiple blind holes 20 arranged at intervals, and the centers of the blind holes 20 in the same row are located on the same circular arc line.

[0077] The positioning straight edge 11 is towards the center of the graphite disc, and the perpendicular bisector of the positioning straight edge 11 coincides with the diameter of the graphite disc.

[0078] The blind holes 20 in each partition 30 are arranged at intervals along the circular arc line, so that the blind holes 20 in each partition 30 jointly form a fan ring shape. Since the blind holes in each hole group in the same partition 30 are distributed around the center of the circular arc line, the cross-sectional area of the blind holes 20 uniformly changes along the direction away from the center of the graphite disc, and the heat conduction capacity also uniformly changes along the direction away from the center of the graphite disc, so as to improve the phenomenon of uneven temperature on the sapphire substrate due to centrifugal force.

[0079] Figure 4 is a structural schematic diagram of a light emitting diode chip provided by an embodiment of the present disclosure. As shown in Figure 4 , the light emitting diode chip includes the sapphire substrate as described above.

[0080] As shown in Figure 4 , the light emitting diode chip further includes an epitaxial wafer stacked on the sapphire substrate, and the epitaxial wafer includes a low-temperature AlN layer 41, a high-temperature AlN layer 42, an n-type AlGaN layer 43, a multiple quantum well layer 44, a p-type AlGaN barrier layer 45, a p-type AlGaN layer 46, and a p-type GaN layer 47 stacked in sequence.

[0081] In the embodiments of the present disclosure, a high-temperature MOCVD device is used to grow the epitaxial wafer. In the process, high-purity hydrogen or high-purity nitrogen or a mixture of high-purity hydrogen and high-purity nitrogen is used as the carrier gas, high-purity ammonia is used as the nitrogen source, trimethyl gallium and triethyl gallium are used as the gallium source, trimethyl indium is used as the indium source, silane is used as the N-type dopant, i.e., the Si source, and trimethyl aluminum is used as the aluminum source, and dimethyl magnesium is used as the P-type dopant, i.e., the Mg source. The pressure in the reaction chamber is 100-600 torr.

[0082] The specific preparation process is as follows:

[0083] First, the sapphire substrate is subjected to special cleaning treatment as the growth substrate.

[0084] Then, the substrate is placed in the MOCVD to grow a low-temperature AlN layer 41. The process temperature of the MOCVD is 1100°C, the pressure is 100 torr, ammonia and trimethyl aluminum are introduced as the reactants, the V / III molar ratio is 3000, and the process time is 1000 s.

[0085] Next, the temperature is raised to 1350°C to grow a high-temperature AlN layer 42 with a thickness of 2.5 μm. The growth pressure is 100 torr, ammonia and trimethyl aluminum are introduced as the reactants, the V / III molar ratio is 300, and the process time is 5000 s.

[0086] Then, a silane-doped n-type AlGaN layer 43 with a thickness of 700 nm is grown at a temperature of 1060°C. The growth pressure is 200 torr.

[0087] Next, an AlGaN layer 44 with a thickness of 100 nm is grown at a temperature of 1040°C and a growth pressure of 150 torr in a nitrogen atmosphere. The AlGaN layer 44 is grown for 5 cycles. x Ga 1-x N / Al y Ga 1-y N(x<y) multiple quantum well layer, in which the thicknesses of the AlGaN barrier layer and the AlGaInN well layer are 3 nm and 11 nm, respectively. x Ga 1-x N layer and the well layer Al y Ga 1-y N layer are 3 nm and 11 nm, respectively.

[0088] Next, a Mg-doped p-type AlGaN barrier layer 45 with a thickness of 30 nm is grown at a temperature of 980°C and a growth pressure of 200 torr.

[0089] Then, a Mg-doped p-type AlGaN layer 46 with a thickness of 25 nm is grown at a temperature of 900°C and a growth pressure of 300 torr.

[0090] Then, a p-type Mg-doped GaN layer 47 with a thickness of 5 nm is grown at a temperature of 850°C and a growth pressure of 400 torr.

[0091] Finally, the epitaxial wafer is completed by annealing for 30 minutes in a nitrogen atmosphere.

[0092] The above is not intended to limit the present disclosure in any form, although the present disclosure has been disclosed as above by way of examples, but is not intended to limit the present disclosure. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to form equivalent examples of equivalent changes without departing from the technical solution of the present disclosure. Any simple modification, equivalent change and modification made to the above examples according to the technical essence of the present disclosure shall still fall within the scope of the technical solution of the present disclosure.

Claims

1. A sapphire substrate, characterized by, The sapphire substrate (10) has a positioning straight edge (11) on the side for epitaxial growth, the side for epitaxial growth has a plurality of blind holes (20), the cross-sectional area of the plurality of blind holes (20) gradually increases in the direction away from the positioning straight edge (11), and the positioning straight edge (11) is towards the center of the graphite disc.

2. The sapphire substrate of claim 1, wherein The side for epitaxial growth has a plurality of partitions (30), and the plurality of partitions (30) are arranged in sequence from the positioning straight edge (11) to the direction away from the positioning straight edge (11). The cross-sectional area of the blind holes (20) in the same partition (30) is the same, and the cross-sectional area of the blind holes (20) in each partition (30) gradually increases from the positioning straight edge (11) to the direction away from the positioning straight edge (11).

3. The sapphire substrate of claim 2, wherein, The same partition (30) includes at least one row of spaced blind holes (20), and the centers of the blind holes (20) in the same row are located on the same circular arc line.

4. The sapphire substrate according to any one of claims 1 to 3, wherein The blind hole (20) includes a counterbore section (210) and a tapered hole section (220), one end of the counterbore section (210) is coaxially connected to the small end of the tapered hole section (220), and the large end of the tapered hole section (220) is located on the side for epitaxial growth. The diameters of the counterbore sections (210) of the plurality of blind holes (20) are the same, and the diameters of the large ends of the tapered hole sections (220) gradually increase from the positioning straight edge (11) to the direction away from the positioning straight edge (11).

5. The sapphire substrate of claim 4, wherein, The diameter of the counterbore section (210) is 100-600 nm, and the length of the counterbore section (210) in the direction perpendicular to the side for epitaxial growth is 100-500 nm.

6. The sapphire substrate of claim 4, wherein, The length of the tapered hole section (220) is 100-500 nm, the diameter of the large end of the tapered hole section (220) is 800-1200 nm, and the diameter of the small end of the tapered hole section (220) is 500-700 nm.

7. The sapphire substrate according to any one of claims 1 to 3, wherein The distance between adjacent two blind holes (20) is 800-1500 nm.

8. A method of producing a sapphire substrate, characterized by, The preparation method comprises: providing a sapphire substrate; forming a plurality of blind holes on the side for epitaxial growth of the sapphire substrate, the side for epitaxial growth has a positioning straight edge, and the cross-sectional area of the plurality of blind holes gradually increases in the direction away from the positioning straight edge, and the positioning straight edge is towards the center of the graphite disc.

9. The production method according to claim 8, characterized by, The method for forming a plurality of blind holes on the side for epitaxial growth of the sapphire substrate comprises: etching the side for epitaxial growth of the sapphire substrate to form blind holes, the blind holes have a counterbore section and a tapered hole section, one end of the counterbore section is coaxially connected to the small end of the tapered hole section, and the large end of the tapered hole section is located on the side for epitaxial growth.

10. A light emitting diode chip, characterized by The light-emitting diode chip comprises the sapphire substrate according to any one of claims 1-7.

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