LED chip based on an aluminum oxide silicon dioxide composite substrate and a manufacturing process for it

Abstract

LED chip based on an aluminum oxide-silicon dioxide composite substrate, comprising: an aluminum oxide-silicon dioxide composite PSS substrate, a composite buffer layer and an LED structure layer, wherein the composite buffer layer is epitaxially grown on the aluminum oxide-silicon dioxide composite PSS substrate and the LED structure layer is epitaxially grown on the composite buffer layer; wherein the composite buffer layer comprises an aluminum oxynitride / aluminum nitride layer and a silicon oxynitride layer; wherein the aluminium oxide in the aluminium oxide-silicon dioxide composite PSS substrate is covered with the aluminium oxynitride / aluminium nitride layer and the silicon dioxide in the aluminium oxide-silicon dioxide composite PSS substrate is covered with the aluminium oxynitride / aluminium nitride layer and the silicon oxynitride layer in an offset manner; and wherein the aluminum oxynitride in the aluminum oxynitride / aluminum nitride layer with is connected to the aluminum oxide-silicon dioxide composite PSS substrate, and the aluminum nitride in the aluminum oxynitride / aluminum nitride layer is connected to the LED structural layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED chips and, in particular, to an LED chip based on an alumina-silicon dioxide composite substrate and a method for producing the same. STATE OF THE ART

[0002] LED (Light Emitting Diode) is a widely used light-emitting device that releases energy through the recombination of electrons and holes, emitting light. LED products are widely used in various industries and play an important role in daily life and manufacturing. The MOCVD (Metal-Organic Chemical Vapor Deposition) method is mainly used in industry to produce LED epitaxial wafers, generally using a PSS (Patterned Sapphire Substrate). A dry etching mask is grown on the PSS substrate, and the mask is patterned using a standardized photolithography process. The sapphire is then etched using an ICP (Inductively Coupled Plasma) etching technique.The mask is removed, and a GaN (gallium nitride) material is grown on it, transforming the vertical epitaxy of the GaN material into a lateral epitaxy. On the one hand, the dislocation density of the epitaxial GaN material can be effectively reduced, thus reducing non-radiative recombination in the active region, reducing reverse leakage current, and improving the lifetime of the LED. On the other hand, the light emitted from the active region changes the exit angle of the totally reflected light through multiple scattering at the interface between GaN and the sapphire substrate, increasing the probability that the light emitted by the inverted LED will exit the sapphire substrate, thereby improving the luminous efficiency.

[0003] The LED market tends to be stable and routinely manufactured. There is increasing demand for higher-quality, sophisticated products, especially those with high luminous efficiency. However, improving internal quantum efficiency is more difficult, so improving external quantum efficiency and light extraction efficiency is more important. To improve external quantum efficiency and light extraction efficiency in the industry, an alumina-silicon dioxide (Al2O3 / SiO2) composite PSS substrate is typically used in combination with an LED barrier crystal underlayer, i.e., an Al2O3 / SiO2 composite PSS substrate is used. A layer of AlN (aluminum nitride) is epitaxially grown as a buffer layer on the Al2O3 / SiO2 composite PSS substrate pattern, and then an LED structural layer is epitaxially grown on the buffer layer.

[0004] However, due to the growth rate of AlN and GaN materials, the difference between the Al2O3 material and the SiO2 material in the pattern part of the Al2O3 / SiO2 composite PSS substrate is relatively large, resulting in poor thickness uniformity of the AlN buffer layer. On the other hand, the Al2O3 / SiO2 composite PSS substrate exhibits poor lattice quality in the SiO2 pattern and SiO2 material layer, and there are some problems, such as a high concentration of oxygen vacancy defects.

[0005] CN 1 09 786 524 A describes an LED epitaxial layer with a PSS structure.

[0006] US 2013 / 0 320 353 A1 discloses a method for depositing a single-crystalline film of group III nitride. DISCLOSURE OF THE INVENTION

[0007] The present application provides an LED chip based on an alumina-silicon oxide composite substrate and a manufacturing method thereof to solve the problems of poor thickness uniformity and poor lattice quality of an AlN buffer layer used.

[0008] In a first aspect, the present application provides an LED chip based on an alumina-silicon oxide composite substrate, comprising: an alumina-silicon dioxide composite PSS substrate, a composite buffer layer, and an LED structural layer, wherein the composite buffer layer is epitaxially grown on the alumina-silicon dioxide composite PSS substrate, and the LED structural layer is epitaxially grown on the composite buffer layer; wherein the composite buffer layer comprises an aluminum oxynitride / aluminum nitride layer and a silicon oxynitride layer, wherein the aluminum oxide in the alumina-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer, and the silicon dioxide in the alumina-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer and the silicon oxynitride layer in a staggered manner;and wherein the aluminum oxynitride in the aluminum oxynitride / aluminum nitride layer is bonded to the aluminum oxide-silicon dioxide composite PSS substrate and the aluminum nitride in the aluminum oxynitride / aluminum nitride layer is bonded to the LED structure layer.;

[0009] In some embodiments, the thickness of the aluminum oxynitride in the aluminum oxynitride / aluminum nitride layer is 30% - 60% of the total thickness of the aluminum oxynitride / aluminum nitride layer.

[0010] In some embodiments, the aluminum oxynitride / aluminum nitride layer has a thickness of 10 nm - 25 nm and the silicon oxynitride layer has a thickness of 10 nm - 30 nm.

[0011] In a second aspect, the present invention also provides a method for manufacturing the LED chip based on an alumina-silicon dioxide composite substrate, the manufacturing method comprising: placing an alumina-silicon dioxide composite PSS substrate in a physical vapor deposition apparatus and epitaxially growing an aluminum oxynitride / aluminum nitride layer by physical vapor deposition to obtain a first substrate; placing the first substrate in a metal-organic chemical vapor deposition apparatus and epitaxially growing a silicon oxynitride layer by metal-organic chemical vapor deposition to obtain a second substrate; and epitaxially growing an LED structural layer on the second substrate.

[0012] In some embodiments, the step of obtaining the first substrate comprises: bombarding an aluminum target material with argon gas under a nitrogen gas atmosphere in a chamber of the physical vapor deposition apparatus onto a surface of a base plate of the alumina-silicon dioxide composite PSS substrate by magnetron sputtering, introducing oxygen gas, and reacting to obtain an aluminum oxynitride thin film epitaxially grown on the alumina-silicon dioxide composite PSS substrate; and stopping the oxygen supply and reacting to obtain an aluminum nitride thin film epitaxially grown on the aluminum oxynitride layer to obtain the first substrate.

[0013] In some embodiments, the sputtering power of the physical vapor deposition apparatus is set in the range of 3000 W to 4500 W and the sputtering temperature is set in the range of 500 °C to 650 °C, wherein the flow rate for introducing the oxygen is 2 sccm to 6 sccm, and wherein the time for introducing the oxygen is 30% to 60% of the total time of the epitaxial growth of the physical vapor deposition.

[0014] In some embodiments, the step of obtaining the second substrate comprises: performing a thermal treatment of the first substrate in a hydrogen atmosphere at a first predetermined temperature in the metal-organic chemical vapor deposition apparatus, wherein the thermal treatment lasts for a first predetermined time; converting the atmosphere into a mixed atmosphere of nitrogen gas and ammonia gas, wherein the nitrogen gas is a carrier gas and the ammonia gas is a reaction gas, to provide a nitrogen source; performing a thermal substitution reaction at a second predetermined temperature to obtain a silicon oxynitride layer epitaxially grown on the first substrate, wherein the second predetermined temperature is lower than the first predetermined temperature and the thermal substitution reaction lasts for a second predetermined time;and maintaining a mixed atmosphere of nitrogen gas and ammonia gas, controlling and lowering the temperature to a third predetermined temperature to perform an annealing treatment, wherein the third predetermined temperature is lower than the second predetermined temperature and the annealing treatment lasts for a third predetermined time to obtain the second substrate;

[0015] In some embodiments, the first predetermined temperature is in the range of 1050°C - 1150°C and the first predetermined time is in the range of 1 min - 5 min; the second predetermined temperature is in the range of 800°C - 1000°C, and the second predetermined time is in the range of 5 min - 20 min; the third predetermined temperature is in the range of 550°C - 650°C and the third predetermined time is in the range of 20 min - 30 min.

[0016] In some embodiments, the epitaxially grown aluminum oxynitride / aluminum nitride layer has a thickness of 10 nm - 25 nm and the epitaxially grown silicon oxynitride layer has a thickness of 10 nm - 30 nm.

[0017] The present invention provides an LED chip based on an alumina-silica composite substrate and a manufacturing method thereof, the LED chip comprising an alumina-silica composite PSS substrate, a composite buffer layer, and an LED structural layer, wherein the composite buffer layer is epitaxially grown on the alumina-silica composite PSS substrate and the LED structural layer is epitaxially grown on the composite buffer layer.The composite buffer layer comprises: an aluminum oxynitride / aluminum nitride layer and a silicon oxynitride layer, wherein the aluminum oxide in the alumina-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer, and the silicon dioxide in the alumina-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer and the silicon oxynitride layer in a staggered manner, wherein the aluminum oxynitride in the aluminum oxynitride / aluminum nitride layer is bonded to the alumina-silicon dioxide composite PSS substrate, and the aluminum nitride in the aluminum oxynitride / aluminum nitride layer is bonded to the LED structure layer.The composite buffer layer has a more uniform thickness on the alumina and silica materials and can better buffer the lattice mismatch and stress relaxation from the alumina-silica composite PSS substrate to the LED barrier crystal underlayer due to the different materials, thereby reducing the defects at the interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly explain the technical solution of the present application, the drawings to be used in the embodiments are briefly presented below. It is obvious that a person skilled in the art can obtain other drawings based on these drawings without inventive effort. Fig. 1 is a schematic diagram of a structure of an LED chip based on an alumina-silicon dioxide composite substrate according to some embodiments of the present application; Fig. 2 is a schematic diagram of a structure of an Al2O3 / SiO2 composite PSS substrate; Fig. 3 is a schematic diagram of a structure of an AlN buffer layer; Fig. Figure 4 is a schematic diagram of the structure of an LED chip with an AlN buffer layer; Fig. 5 is a TEM image I of an LED chip with an AlN buffer layer; Fig. 6 is a TEM image II of an LED chip with an AlN buffer layer; Fig. 7 is the TEM image I of an LED chip based on an alumina-silica composite substrate provided according to some embodiments of the present application; Fig. 8 is a TEM image II of an LED chip based on an alumina-silica composite substrate provided in accordance with some embodiments of the present application; Fig. 9 is a schematic flow diagram of a manufacturing method of an LED chip based on an alumina-silicon dioxide composite substrate provided in accordance with some embodiments of the present application; Fig. 10 is a schematic flow diagram of the epitaxial growth of a SiO x N y layer by MOCVD on a first substrate to obtain a second substrate provided according to some embodiments of the present application; Fig. Figure 11 is a schematic representation of a structure for the epitaxial growth of an AlO x N ylayer on an Al2O3 / SiO2 composite PSS substrate provided according to some embodiments of the present application; Fig. 12 is a schematic representation of a structure for epitaxially growing an AlN layer on an AlO x N y layer provided according to some embodiments of the present application; Fig. 13 is a schematic representation of a structure after thermal treatment of an AlO x N y / AlN layer provided according to some embodiments of the present application; Fig. 14 is a schematic illustration of a structure of a composite buffer layer provided in accordance with some embodiments of the present application; Fig. 15 is a partially enlarged schematic structural diagram at A in Fig. 14. EMBODIMENTS OF THE INVENTION

[0019] Below, embodiments illustrated in the accompanying drawings are explained in detail. When referring to the accompanying drawings in the following description, like reference numerals in different figures indicate the same or similar elements unless otherwise noted. The implementations described in the following embodiments do not represent all implementations compatible with the present application. They are merely examples of systems and methods consistent with certain aspects of the present application, as described in the claims.

[0020] Epitaxial growth refers to the growth of a single-crystal layer on a single-crystal substrate (base plate) with a specific requirement and the same crystal orientation as the substrate, as if the original crystal had expanded to a certain extent. There are various methods for growing epitaxial layers, including liquid-phase epitaxy (LPE), physical vapor deposition (PVD), metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), and molecular beam epitaxy (MBE). Generally, the MOCVD epitaxial growth method is the most widely used for industrial production.

[0021] MOCVD is a new vapor-phase epitaxy process developed based on vapor-phase epitaxy (VPE). MOCVD is a process in which organic compounds of Group III and II elements and hydrides of Group V and VI elements are used as starting materials for crystal growth. Various III-V main group and II-VI subgroup compound semiconductors and their multicomponent solid solutions are grown on a substrate by vapor-phase epitaxy in a thermal decomposition reaction to obtain a thin-film single-crystal material. MOCVD has the advantages of precise control of crystal growth, good repeatability, high yield, and is suitable for industrial production.

[0022] The PVD process is a process in which the surface of a material source (solid or liquid) is physically evaporated into gaseous atoms or molecules or partially ionized into ions under vacuum, and a thin film with a specific function is deposited on the surface of a substrate by a low-pressure gas (or plasma) process.

[0023] In some embodiments, with reference to Fig. 2 shows an Al2O3 / SiO2 composite PSS substrate. A layer of AlN (aluminum nitride) is epitaxially grown on the Al2O3 / SiO2 composite PSS substrate pattern as a buffer layer (see Fig. 3). An LED structure layer is then epitaxially grown on the AlN buffer layer (see Fig. 4).

[0024] On the one hand, however, there is a relatively large difference between the growth rates of the AlN and GaN materials on the Al2O3 material and on the SiO2 material in the Al2O3 / SiO2 composite PSS substrate pattern section. On the other hand, the SiO2 material layer in the SiO2 pattern of the Al2O3 / SiO2 composite PSS substrate has poor lattice quality. There are some problems, such as a high concentration of oxygen vacancies. Fig. 5 and Fig. 6 show microscopic images taken with a transmission electron microscope (TEM) in the aforementioned embodiments. As can be seen from Fig. As can be seen in Figure 6, the thickness of the AlN buffer layer on the SiO2 material of a sample part of the Al2O3 / SiO2 composite PSS substrate is 4.9 nm and 7.4 nm, while the thickness of the AlN buffer layer on the Al2O3 material of a sample part of the Al2O3 / SiO2 composite PSS substrate is 12.5 nm and 15.2 nm. It can be seen that the thickness difference between these two layers is almost twice as large, and the thickness uniformity is not good. From the arrow positions in Fig. However, it can be clearly seen in Figure 5 that oxygen vacancy defects exist in the SiO2 pattern part of the Al2O3 / SiO2 composite PSS substrate.

[0025] To solve the above-mentioned problem, the present application provides an LED chip based on an alumina-silicon dioxide composite substrate, see Fig. 1. It comprises an alumina-silicon dioxide (Al2O3 / SiO2) composite PSS substrate, a composite buffer layer, and an LED structural layer, wherein the composite buffer layer is epitaxially grown on the alumina-silicon dioxide composite PSS substrate and the LED structural layer is epitaxially grown on the composite buffer layer.

[0026] The composite buffer layer is used to better buffer the lattice mismatch and stress relief from the Al2O3 / SiO2 composite PSS substrate to the LED barrier crystal sublayer due to the different materials, and to reduce defects at the interface. The LED structural layer is the main working structural layer of the LED. For example, the LED structural layer may include a U-shaped GaN layer, an N-shaped GaN layer, a stress relief layer, an electron enrichment layer, a multi-quantum well layer, and a P-type layer. The U-shaped GaN layer is used as the LED barrier crystal sublayer to improve external quantum efficiency and luminous efficiency. The N-type GaN layer serves to form an N-type region of the LED. An electron provided by the N-type region recombines with a hole in the quantum well to excite light, which is one of the main structures of the LED.The stress relief layer is used to relieve stress between the lattices. An electron enrichment layer ensures electron enrichment in the N-type region. A multiple quantum well (MQW) refers to a system in which multiple quantum wells are combined. In terms of material structure and growth process, there is no significant difference between multiple quantum wells and superlattices, except that the superlattice interface is relatively thin and the coupling between the potential wells is strong, forming microstripes, while the interface between multiple quantum wells is thick and there is essentially no tunnel coupling, thus preventing the formation of microstripes. The multiple quantum well structure is used primarily for its optical properties and is one of the fundamental structural layers of the LED epitaxial structure.The P-layer, used to form the P-type region of the LED, is one of the main structures of the LED.

[0027] The composite buffer layer comprises an aluminum oxynitride / aluminum nitride layer (AlO x N y / AlN) and a silicon oxynitride layer (SiO x N y ), wherein the aluminum oxide in the aluminum oxide-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer, and the silicon dioxide in the aluminum oxide-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer and the silicon oxynitride layer in a staggered manner. The aluminum oxynitride (AlO x N y ) in the aluminum oxynitride / aluminum nitride layer is bonded to the aluminum oxide-silicon dioxide composite PSS substrate. The aluminum nitride (AlN) in the aluminum oxynitride / aluminum nitride layer is bonded to the LED structural layer.

[0028] In an exemplary embodiment, the thickness of the aluminum oxynitride in the aluminum oxynitride / aluminum nitride layer is 30%-60% of the total thickness of the aluminum oxynitride / aluminum nitride layer. This can reduce lattice defects and make the lattice denser.

[0029] In an exemplary embodiment, the aluminum oxynitride / aluminum nitride layer has a thickness of 10 nm - 25 nm and the silicon oxynitride layer has a thickness of 10 nm - 30 nm. This allows it to better buffer lattice mismatches and stress relaxation due to different materials and reduce defects at the interface.

[0030] The Fig. 7 and Fig. 8 are TEM images I and II, respectively, of an LED chip based on an alumina-silicon dioxide composite substrate provided according to some embodiments of the present application. Fig. 8 shows that the thickness of the composite buffer layer on the SiO2 material of a sample part of the Al2O3 / SiO2 composite PSS substrate is 5.7 nm and 12.4 nm, while the thickness of the composite buffer layer on the Al2O3 material of the sample part of the Al2O3 / SiO2 composite PSS substrate is 8.8 nm and 11.7 nm. It can be seen that the thickness of the two layers is not so different. However, there is no obvious lattice defect in the SiO2 sample part of the Al2O3 / SiO2 composite PSS substrate in Fig. 7 can be seen, and the crystal lattice is denser.

[0031] Based on the above-mentioned embodiments, the present application also provides a method for manufacturing the LED chip based on an alumina-silicon dioxide composite substrate in the above-mentioned embodiments of the present application. As in Fig. As shown in Figure 9, the manufacturing process includes: S100: An Al2O3 / SiO2 composite PSS substrate is placed in a physical vapor deposition (PVD) apparatus, and an AlOxNy / AlN layer is epitaxially grown by physical vapor deposition to obtain a first substrate.

[0032] In a chamber of the PVD device, the sputtering power of the PVD device is set to a range of 3000 W–4500 W and a sputtering temperature of 500 °C–650 °C. In a nitrogen (N2) atmosphere, an aluminum (Al) target is bombarded with argon (Ar) gas onto the surface of a base plate of the Al2O3 / SiO2 composite PSS substrate by magnetron sputtering. First, oxygen (O2) is introduced at a flow rate of 2 sccm–6 sccm (standard cubic centimeters per minute) to react to form an AlO x N y film epitaxially grown on the Al2O3 / SiO2 composite PSS substrate. As shown in Fig. As shown in Figure 11, the time for supplying O2 is 30% - 60% of the total time for epitaxial PVD growth, ie the thickness of the AlO x N y is 30% - 60% of the total thickness of the AlO x N y / AlN layer. After that, the oxygen supply is stopped. The reaction leads to an aluminum nitride (AlN) film, which is deposited on the aluminum oxynitride (AlO x N y ) layer is grown epitaxially. With reference to Fig. 12, a first substrate is obtained, wherein the first substrate is an Al2O3 / SiO2 composite PSS substrate with a PVD deposited AlO x N y / AlN layer.

[0033] S200: The first substrate is placed in a metal-organic chemical vapor deposition device, and a silicon oxynitride layer is epitaxially grown by metal-organic chemical vapor deposition to obtain a second substrate. With reference to Fig. 10 S200 is realized by S210-S230.

[0034] S210: In the MOCVD apparatus, the first substrate is thermally treated at a first predetermined temperature.

[0035] The first substrate is introduced into a metal-organic chemical vapor deposition (MOCVD) device, in which the first substrate is subjected to a thermal treatment in a hydrogen atmosphere (H2) at a first predetermined temperature. For example, the first predetermined temperature is in the range of 1050°C to 1150°C. The thermal treatment is carried out for a first predetermined time. For example, the first predetermined time is in the range of 1 minute to 5 minutes. As in Fig. 13, the AlO x N y / AlN layer on a surface layer with a SiO2 pattern is difficult to produce by deposition. The SEM scan shows that the growth morphology is a non-film-like, irregularly discontinuous distribution. Therefore, thermal treatment is required to remove impurities such as water and oxygen in the surface layer of the substrate. In the high-temperature process, the composite substance of the AlO x N y / AlN layer deposited on the surface layer of SiO2 undergoes an agglomeration effect to form granular particles with a larger interval. This exposes a larger area of ​​the surface layer of SiO2.

[0036] S220: A thermal substitution reaction is carried out at a second predetermined temperature to obtain a SiOxNy layer.

[0037] The atmosphere is converted into a mixed atmosphere of nitrogen (N2) and ammonia (NH3), where N2 is a carrier gas and NH3 is a reactant gas, to provide a nitrogen (N) source. The thermal substitution reaction is carried out at a second predetermined temperature, wherein the second predetermined temperature is lower than the first predetermined temperature. For example, the second predetermined temperature is in the range of 800 °C to 1000 °C. The reaction leads to epitaxial growth of a SiO x N y -layer on the first substrate. As shown in Fig. As shown in Figure 14, the thermal substitution reaction continues for a second predetermined time. For example, the second predetermined time is in the range of 5 min-20 min to determine the thickness and concentration of the N-substitution component of the SiO x N y -layer on the SiO2 surface layer.

[0038] S230: The temperature is lowered to a third predetermined temperature for annealing to obtain a second substrate.

[0039] The mixed atmosphere of N2 and NH3 is maintained, and the temperature is controlled to decrease to a third predetermined temperature for the annealing treatment, wherein the third predetermined temperature is lower than the second predetermined temperature. For example, the third predetermined temperature is in the range of 550 °C - 650 °C. The annealing treatment is carried out for a third predetermined time. For example, the third predetermined time is in the range of 20 min to 30 min in order to remove a large amount of H impurities present in the surface layer of the SiO x N y film produced during the thermal exchange reaction in step S220. After annealing, a second substrate is obtained, see Fig. 14. The second substrate is an Al2O3 / SiO2 composite PSS substrate with a composite buffer layer. The composite buffer layer comprises: an AlO x N y / AlN layer and a SiO x N y -layer, wherein the Al2O3 in the Al2O3 / SiO2 composite PSS substrate is bonded to the AlO x N y / AlN layer and the SiO2 in the Al2O3 / SiO2 composite PSS substrate is covered with the AlO x N y / AlN layer and the SiO x N y -layer is covered in a staggered manner, see Fig. 15. For example, the thickness of the epitaxially grown AlO x N y / AlN layer 10 nm -25 nm and the thickness of the epitaxially grown SiO x N y -Layer 10 nm -30 nm

[0040] S300: An LED structural layer is grown epitaxially on the second substrate.

[0041] For example, LED structural layers such as a U-type GaN layer, an N-type GaN layer, a stress relief layer, an electron enrichment layer, a multi-quantum well layer, and a P-type layer can be epitaxially grown sequentially on the second substrate. Any method can be used for epitaxially growing the LED structural layers. Detailed descriptions thereof are omitted in the present application.

[0042] The Fig. 7 and Fig. 8 show TEM images of LED chips produced using the manufacturing process described above. Fig. 8 shows that the thickness of the composite buffer layer on the SiO2 material of a sample part of the Al2O3 / SiO2 composite PSS substrate is 5.7 nm and 12.4 nm, while the thickness of the composite buffer layer on the Al2O3 material of the sample part of the Al2O3 / SiO2 composite PSS substrate is 8.8 nm and 11.7 nm. It can be seen that the thickness of the two layers is not so different. However, it is Fig. 7 shows that the SiO2 pattern part of the Al2O3 / SiO2 composite PSS substrate has no obvious lattice defects and its lattice is denser. Compared to the LED chip in Fig. 5 and Fig. 6, the thickness uniformity of the composite buffer layer on the Al2O3 material and on the SiO2 material of the Al2O3 / SiO2 composite PSS substrate is greatly improved. There are no obvious lattice defects in the SiO2 pattern portion, and the lattice quality is also greatly improved.

[0043] The present application provides an LED chip based on an alumina-silicon oxide composite substrate and a manufacturing method therefor, wherein the LED chip comprises an alumina-silicon oxide composite PSS substrate, a composite buffer layer, and an LED structural layer. A composite buffer layer is epitaxially grown on the alumina-silicon oxide composite PSS substrate, and the LED structural layer is epitaxially grown on the composite buffer layer. The composite buffer layer comprises: an aluminum oxynitride / aluminum nitride layer and a silicon oxynitride layer, wherein the aluminum oxide in the alumina-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer, and the silicon dioxide in the alumina-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer and the silicon oxynitride layer in a staggered manner.The aluminum oxynitride in the aluminum oxynitride / aluminum nitride layer is bonded to the alumina-silicon dioxide composite PSS substrate, and the aluminum nitride in the aluminum oxynitride / aluminum nitride layer is bonded to the LED structural layer. The composite buffer layer has better thickness uniformity across the alumina and silicon dioxide materials and can better buffer the lattice mismatch and stress relief from the alumina-silicon dioxide composite PSS substrate to the LED barrier crystal sublayer due to the different materials. This can reduce defects at the interface.

Claims

[1] An LED chip based on an alumina-silica composite substrate, comprising: an alumina-silica composite PSS substrate, a composite buffer layer, and an LED structural layer, wherein the composite buffer layer is epitaxially grown on the alumina-silica composite PSS substrate and the LED structural layer is epitaxially grown on the composite buffer layer; wherein the composite buffer layer comprises an aluminum oxynitride / aluminum nitride layer and a silicon oxynitride layer; wherein the aluminum oxide in the aluminum oxide-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer, and the silicon dioxide in the aluminum oxide-silicon dioxide composite PSS substrate is covered with the aluminum oxynitride / aluminum nitride layer and the silicon oxynitride layer in a staggered manner; and wherein the aluminum oxynitride in the aluminum oxynitride / aluminum nitride layer is the alumina-silicon dioxide composite PSS substrate, and the aluminum nitride in the aluminum oxynitride / aluminum nitride layer is bonded to the LED structure layer. [2] The alumina-silicon dioxide composite substrate-based LED chip according to claim 1, wherein the thickness of the aluminum oxynitride in the aluminum oxynitride / aluminum nitride layer is 30%-60% of the total thickness of the aluminum oxynitride / aluminum nitride layer. [3] The alumina-silicon dioxide composite substrate-based LED chip according to claim 1, wherein the aluminum oxynitride / aluminum nitride layer has a thickness of 10 nm - 25 nm and the silicon oxynitride layer has a thickness of 10 nm - 30 nm. [4] A method of manufacturing an LED chip based on an alumina-silicon dioxide composite substrate according to any one of claims 1 to 3, the method comprising: Placing the alumina-silicon dioxide composite PSS substrate in a physical vapor deposition apparatus and epitaxially growing an aluminum oxynitride / aluminum nitride layer by physical vapor deposition to obtain a first substrate; Placing the first substrate in a metal-organic chemical vapor deposition device and epitaxially growing the silicon oxynitride layer by metal-organic chemical vapor deposition to obtain a second substrate; and epitaxial growth of the LED structural layer on the second substrate. [5] The method of claim 4, wherein the step of obtaining the first substrate comprises: Bombarding an aluminum target material with argon gas in a nitrogen gas atmosphere in a chamber of the physical vapor deposition apparatus onto a surface of a base plate of the alumina-silica composite PSS substrate by magnetron sputtering, introducing oxygen gas, and reacting to obtain an aluminum oxynitride thin film epitaxially grown on the alumina-silica composite PSS substrate; Stopping the oxygen supply and reacting to obtain an aluminum nitride thin film epitaxially grown on the aluminum oxynitride layer to obtain the first substrate. [6] The method according to claim 5, wherein a sputtering power of the physical vapor deposition apparatus is set in the range of 3000 W to 4500 W and a sputtering temperature is set in the range of 500 °C to 650 °C; the flow rate for introducing the oxygen gas is 2 sccm to 6 sccm, and the time for introducing the oxygen gas is 30% to 60% of the total time for epitaxial growth by the physical vapor deposition. [7] The method of claim 4, wherein the step of obtaining the second substrate comprises: performing a thermal treatment of the first substrate in a hydrogen atmosphere at a first predetermined temperature in the metal-organic chemical vapor deposition apparatus, wherein the thermal treatment lasts for a first predetermined time; Converting the atmosphere into a mixed atmosphere of nitrogen gas and ammonia gas, wherein the nitrogen gas is a carrier gas and the ammonia gas is a reaction gas, to provide a nitrogen source; performing a thermal substitution reaction at a second predetermined temperature to obtain the silicon oxynitride layer epitaxially grown on the first substrate, wherein the second predetermined temperature is lower than the first predetermined temperature and the thermal substitution reaction lasts for a second predetermined time; and Maintaining a mixed atmosphere of nitrogen gas and ammonia gas, controlling and lowering the temperature to a third predetermined temperature to perform an annealing treatment, wherein the third predetermined temperature is lower than the second predetermined temperature and the annealing treatment lasts for a third predetermined time to obtain the second substrate. [8] The method according to claim 7, wherein the first predetermined temperature is in the range of 1050 °C - 1150 °C and the first predetermined time is in the range of 1 min - 5 min; the second predetermined temperature is in the range of 800 °C - 1000 °C and the second predetermined time is in the range of 5 min - 20 min; and the third predetermined temperature is in the range of 550 °C - 650 °C and the third predetermined time is in the range of 20 min - 30 min. [9] The method of claim 4, wherein the aluminum oxynitride / aluminum nitride layer is epitaxially grown to a thickness of 10 nm - 25 nm and the silicon oxynitride layer is epitaxially grown to a thickness of 10 nm - 30 nm.

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