Method for preparing epitaxial wafer with Bragg reflector

Abstract

The present invention provides a method for preparing an epitaxial wafer with a Bragg reflector, and belongs to the technical field of light-emitting diodes. After the n-type layer, active layer and p-type layer are grown on the substrate, multiple SiO2 refractive layers and Ti3O5 refractive layers are alternately evaporated to obtain a Bragg reflector. The evaporation rate of the SiO2 refractive layer is a first evaporation rate to obtain a SiO2 refractive layer with a surface roughness of 0.5 to 0.8 nm, and the evaporation rate of the Ti3O5 refractive layer is a second evaporation rate to obtain a Ti3O5 refractive layer with a surface roughness of 1.0 to 1.1 nm; the roughness is reasonable, the particles that appear at the junction of the SiO2 refractive layer and the Ti3O5 refractive layer will be reduced, and the junction of the SiO2 refractive layer and the Ti3O5 refractive layer is relatively flat and the roughness is also low. The microscopic crystal quality and interlayer quality of the obtained Bragg reflector are effectively improved to improve the reflective efficiency of the Bragg reflector.

Description

Technical Field

[0001] The present disclosure relates to the technical field of light emitting diodes, and in particular to a method for preparing an epitaxial wafer with a Bragg reflector. Background Art

[0002] Light-emitting diodes are semiconductor electronic components that can emit light. As a new type of efficient, environmentally friendly, green solid-state lighting source, they are rapidly and widely used, such as traffic lights, car interior and exterior lights, urban landscape lighting, mobile phone backlights, etc. Improving the chip's luminous efficiency is the goal that light-emitting diodes are constantly pursuing.

[0003] The LED epitaxial wafer is the basic structure for preparing LEDs. Common LED epitaxial wafers include a substrate and an n-type layer, an active layer, a p-type layer and a Bragg reflector stacked on the substrate in sequence. The added Bragg reflector can reflect most of the light, increase the light emitted from the light-emitting surface of the LED epitaxial wafer, and thus improve the light-emitting efficiency of the final LED.

[0004] Since the Bragg reflector itself is obtained by alternately growing refractive layers of different materials, there are certain lattice mismatches and defects inside. Combined with the fact that the Bragg reflector is usually grown on a material different from the Bragg reflector itself, it is easy for the Bragg reflector to be rough and of poor quality, thus affecting the reflective performance of the Bragg reflector. Summary of the invention

[0005] The disclosed embodiment provides a method for preparing an epitaxial wafer with a Bragg reflector, which can improve the roughness, quality and reflective performance of the Bragg reflector. The technical solution is as follows:

[0006] The embodiment of the present disclosure provides a light-emitting diode epitaxial wafer, and the method for preparing the light-emitting diode epitaxial wafer having a Bragg reflector comprises:

[0007] An n-type layer, an active layer and a p-type layer are sequentially grown on a substrate;

[0008] On the p-type layer, a plurality of SiO 2 Refractive layer and Ti 3 O 5 The refractive layer is used to obtain the Bragg reflector, the SiO 2 The evaporation rate of the refractive layer is the first evaporation rate to obtain a SiO2 layer with a surface roughness of 0.5 to 0.8 nm. 2 Refractive layer, the Ti 3 O 5 The evaporation rate of the refractive layer is the second evaporation rate to obtain a Ti with a surface roughness of 1.0 to 1.1 nm. 3 O5 Refraction layer.

[0009] Optionally, the SiO 2 The first evaporation rate of the refractive layer is 4 to 6 angstroms per second, and the Ti 3 O 5 The second evaporation rate of the refractive layer is 1.8-2.2 angstroms / second.

[0010] Optionally, the SiO 2 The evaporation voltage of the refractive layer is 1150-1250V, and the SiO 2 When the ion beam current of the refractive layer is 1150-1250 mA, the SiO 2 Refractive layer O 2 The flux is 45~55sccm.

[0011] Optionally, the Ti 3 O 5 The evaporation voltage of the refractive layer is 1350-1450V, and the SiO 2 When the ion beam current of the refractive layer is 1350-1450 mA, the SiO 2 Refractive layer O 2 The flux is 80-90 sccm, and the SiO 2 The Ar flux of the refractive layer is 10-15 sccm.

[0012] Optionally, the SiO 2 The vapor deposition temperature of the refractive layer is 120°C to 140°C.

[0013] Optionally, the Ti 3 O 5 The vapor deposition temperature of the refractive layer is 120°C to 140°C.

[0014] Optionally, the method for preparing the light-emitting diode epitaxial wafer having a Bragg reflector further comprises:

[0015] Multiple SiO were evaporated at multiple evaporation rates. 2 Test layer;

[0016] Get each of the SiO 2 The SiO of the test layer 2 Test layer roughness;

[0017] The plurality of SiO 2 The test layer was etched and multiple SiO 2 Corrosion rate of test layer;

[0018] According to the plurality of SiO 2 Test layer roughness and multiple SiO2 The test layer corrosion rate determines the SiO 2 The first relationship curve between the corrosion rate and roughness of the material;

[0019] Determine the SiO with the slowest corrosion rate according to the first relationship curve 2 The evaporation rate corresponding to the test layer is the first evaporation rate.

[0020] Optionally, the plurality of SiO 2 The test layer was etched and multiple SiO 2 Test layer corrosion rate, including:

[0021] NH 4 F, HF and water ratio solution corrodes the SiO 2 The test layer, the ratio of NH 4 The ratio of F and HF is 20:1 respectively.

[0022] Optionally, the method for preparing the light-emitting diode epitaxial wafer having a Bragg reflector further comprises:

[0023] After the n-type layer, active layer and p-type layer are sequentially grown on the substrate, a plurality of SiO 2 Refractive layer and Ti 3 O 5 Before forming a refractive layer to obtain a Bragg reflector, the substrate is placed in a pure nitrogen environment with a constant temperature and humidity to stand.

[0024] Optionally, the substrate is placed in a pure nitrogen environment with a temperature of 21° C. to 25° C. and a humidity of less than 15%.

[0025] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure include:

[0026] After the n-type layer, active layer and p-type layer are grown on the substrate, multiple SiO 2 Refractive layer and Ti 3 O 5 The refractive layer is used to obtain a Bragg reflector. The Bragg reflector can realize the normal reflection of light, improve the light extraction efficiency of the light emitting diode epitaxial wafer, and SiO 2 Refractive layer and Ti 3 O 5 The Bragg reflector obtained by alternately stacking the refractive layers also has a good reflection effect on light. Further, the evaporation rate of the SiO2 refractive layer is a first evaporation rate to obtain a SiO2 with a surface roughness of 0.5 to 0.8 nm. 2 Refractive layer, Ti 3 O 5The evaporation rate of the refractive layer is the second evaporation rate to obtain a Ti with a surface roughness of 1.0 to 1.1 nm. 3 O 5 Refractive layer; can obtain SiO with lower roughness 2 Refractive layer and Ti 3 O 5 Refractive layer, SiO 2 Refractive layer and Ti 3 O 5 The roughness of the refractive layer is reasonable, SiO 2 Refractive layer and Ti 3 O 5 The particles at the interface of the refractive layer will be reduced, and SiO 2 Refractive layer and Ti 3 O 5 The junction of the refractive layers is relatively flat and has low roughness, which effectively improves the microscopic crystal quality and interlayer quality of the obtained Bragg reflector, thereby improving the reflective efficiency of the Bragg reflector. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is a flow chart of a method for preparing a light-emitting diode epitaxial wafer with a Bragg reflector provided in an embodiment of the present disclosure;

[0029] Figure 2 It is a structural schematic diagram of a light-emitting diode epitaxial wafer with a Bragg reflector provided in an embodiment of the present disclosure;

[0030] Figure 3 is a schematic diagram of the film state of a Bragg reflector in the prior art provided by an embodiment of the present disclosure;

[0031] Figure 4 is a schematic diagram of the film state of the Bragg reflector provided by an embodiment of the present disclosure;

[0032] Figure 5 It is a flow chart of another method for preparing a light-emitting diode epitaxial wafer with a Bragg reflector provided in an embodiment of the present disclosure;

[0033] Figure 6 It is a schematic diagram of a first relationship curve provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0035] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The words "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity restriction, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", "top", "bottom" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] Available here Figure 1 , Figure 1 is a flow chart of a method for preparing a light-emitting diode epitaxial wafer with a Bragg reflector provided in an embodiment of the present disclosure, with reference to Figure 1 It can be seen that the embodiment of the present disclosure provides a light-emitting diode epitaxial wafer, and the method for preparing the light-emitting diode epitaxial wafer with a Bragg reflector includes:

[0037] S101: growing an n-type layer, an active layer and a p-type layer in sequence on a substrate.

[0038] S102: Alternately evaporate multiple SiO layers on the p-type layer 2 Refractive layer and Ti 3 O 5 Refractive layer to obtain Bragg reflector, SiO 2 The evaporation rate of the refractive layer is the first evaporation rate to obtain a SiO2 layer with a surface roughness of 0.5 to 0.8 nm. 2 Refractive layer, Ti 3 O 5 The evaporation rate of the refractive layer is the second evaporation rate to obtain a Ti with a surface roughness of 1.0 to 1.1 nm. 3 O 5 Refraction layer.

[0039] After the n-type layer, active layer and p-type layer are grown on the substrate, multiple SiO 2 Refractive layer and Ti3 O 5 The refractive layer is used to obtain a Bragg reflector. The Bragg reflector can realize the normal reflection of light, improve the light extraction efficiency of the light emitting diode epitaxial wafer, and SiO 2 Refractive layer and Ti 3 O 5 The Bragg reflector obtained by alternately stacking refractive layers also has a good reflection effect on light. 2 The evaporation rate of the refractive layer is the first evaporation rate to obtain a SiO2 layer with a surface roughness of 0.5 to 0.8 nm. 2 Refractive layer, Ti 3 O 5 The evaporation rate of the refractive layer is the second evaporation rate to obtain a Ti with a surface roughness of 1.0 to 1.1 nm. 3 O 5 Refractive layer; can obtain SiO with lower roughness 2 Refractive layer and Ti 3 O 5 Refractive layer, SiO 2 Refractive layer and Ti 3 O 5 The roughness of the refractive layer is reasonable, SiO 2 Refractive layer and Ti 3 O 5 The particles at the interface of the refractive layer will be reduced, and SiO 2 Refractive layer and Ti 3 O 5 The junction of the refractive layers is relatively flat and has low roughness, which effectively improves the microscopic crystal quality and interlayer quality of the obtained Bragg reflector, thereby improving the reflective efficiency of the Bragg reflector.

[0040] It should be noted that the surface roughness provided in the present disclosure is the average spacing of the microscopic roughness of the profile - Sm.

[0041] Optionally, SiO 2 The first evaporation rate of the refractive layer is 4 to 6 angstroms per second, Ti 3 O 5 The second evaporation rate of the refractive layer is 1.8-2.2 angstroms / second.

[0042] SiO 2 Refractive layer and Ti 3 O 5 When the evaporation rate of the refractive layer is within the above range, SiO 2 Refractive layer and Ti 3 O 5 The quality of the refractive layer itself is good, and the roughness of the two layers can be guaranteed to be reasonable. 2 Refractive layer and Ti3 O 5 The presence of granular particles at the interface of the refractive layer is greatly reduced, thereby ensuring the reflective efficiency of the final Bragg reflector and improving the reflective effect of the Bragg reflector.

[0043] In one implementation provided in the present disclosure, SiO 2 Refractive layer and Ti 3 O 5 The evaporation rate of the refractive layer can be 4-6 angstroms / second and 2 angstroms / second respectively. 2 Refractive layer and Ti 3 O 5 The quality of the refractive layer can improve the quality and reflective efficiency of the final Bragg reflector.

[0044] Optionally, SiO 2 The evaporation voltage of the refractive layer is 1150~1250V, and the growth voltage of SiO 2 When the ion beam current of the refractive layer is 1150-1250 mA, the growth of SiO 2 Refractive layer O 2 The flux is 45~55sccm.

[0045] SiO 2 The evaporation voltage of the refractive layer, SiO 2 When the ion beam current and oxygen flux of the refractive layer are within the above ranges, the obtained SiO 2 The refractive layer is denser and SiO 2 It is also not easy for a large number of particles to appear at the boundary of the refractive layer during the growth process, which effectively improves the quality and reflection efficiency of the final Bragg reflector.

[0046] In one implementation provided in the present disclosure, SiO 2 The evaporation voltage of the refractive layer, SiO 2 The ion beam current voltage and oxygen flux during the evaporation of the refractive layer can be 1200 mA, 1200 V and 50 sccm respectively. 2 The quality of the refractive layer can improve the quality and reflective efficiency of the final Bragg reflector.

[0047] Optionally, SiO 2 The vapor deposition temperature of the refractive layer is 120°C to 140°C.

[0048] SiO 2 When the evaporation temperature of the refractive layer is within the above range, it can ensure that SiO 2 The evaporation efficiency of the refractive layer and SiO 2The evaporation quality of the refractive layer improves the quality and reflective efficiency of the final Bragg reflector.

[0049] For example, SiO 2 The vacuum pressure of the refractive layer can be 1.5*10 -2 pa~9*10 -3 pa.

[0050] Can ensure SiO 2 The evaporation efficiency of the refractive layer and SiO 2 The evaporation quality of the refractive layer improves the quality and reflective efficiency of the final Bragg reflector.

[0051] Optionally, Ti 3 O 5 The vapor deposition temperature of the refractive layer is 120°C to 140°C.

[0052] Ti 3 O 5 When the evaporation temperature of the refractive layer is within the above range, Ti 3 O 5 The evaporation efficiency of the refractive layer and Ti 3 O 5 The evaporation quality of the refractive layer improves the quality and reflective efficiency of the final Bragg reflector.

[0053] For example, Ti 3 O 5 The initial pressure of the refractive layer can be 1.2*10 -3 pa.

[0054] Can guarantee Ti 3 O 5 The evaporation efficiency of the refractive layer and Ti 3 O 5 The evaporation quality of the refractive layer improves the quality and reflective efficiency of the final Bragg reflector.

[0055] Optionally, Ti 3 O 5 The evaporation voltage of the refractive layer is 1350~1450V, and the growth voltage of SiO 2 When the ion beam current of the refractive layer is 1350-1450 mA, the growth of SiO 2 Refractive layer O 2 The flux is 80-90 sccm, growing SiO 2 The Ar flux of the refractive layer is 10-15 sccm.

[0056] Ti 3 O 5 The evaporation voltage of the refractive layer, Ti 3 O5 When the ion beam current and oxygen flux of the refractive layer are within the above ranges, the obtained Ti 3 O 5 The refractive layer is denser and Ti 3 O 5 It is also not easy for a large number of particles to appear at the boundary of the refractive layer during the growth process, which effectively improves the quality and reflection efficiency of the final Bragg reflector.

[0057] In one implementation provided by the present disclosure, Ti 3 O 5 The evaporation voltage of the refractive layer, Ti 3 O 5 The ion beam current and oxygen flux during the evaporation of the refractive layer can be 1400V, 1400Ma and 85sccm respectively. 3 O 5 The quality of the refractive layer can improve the quality and reflective efficiency of the final Bragg reflector.

[0058] Exemplarily, the number of periods of the Bragg reflector may be 14-28.

[0059] When the period number of the Bragg reflector is within the above range, the reflective efficiency of the Bragg reflector can be ensured, while the preparation cost of the Bragg reflector itself will not be too high, and the thickness of the Bragg reflector itself will not be too large to affect the overall light output efficiency of the light-emitting diode epitaxial wafer. The reflective efficiency of the Bragg reflector can be ensured while reducing the preparation cost required for the Bragg reflector itself.

[0060] It should be noted that in the Bragg reflector, Ti 3 O 5 The thickness of the refractive layer is related to SiO 2 The thickness of the refractive layer can be determined according to the wavelength of the light that the Bragg reflector needs to reflect. 3 O 5 The thickness of the refractive layer is related to SiO 2 The refractive layer usually corresponds to one quarter of the waves that need to be reflected.

[0061] For ease of understanding, here is provided Figure 2 , Figure 2 is a schematic structural diagram of a light-emitting diode epitaxial wafer with a Bragg reflector provided in an embodiment of the present disclosure, Figure 2 The light-emitting diode epitaxial wafer can be Figure 1 The light emitting diode epitaxial wafer with a Bragg reflector is prepared by the method for preparing the light emitting diode epitaxial wafer with a Bragg reflector provided in the reference Figure 2It can be seen that the light emitting diode epitaxial wafer with the Bragg reflector 5 may include a substrate 1 and an n-type layer 2, an active layer 3, a p-type layer 4 and a Bragg reflector 5 sequentially stacked on the substrate 1, wherein the Bragg reflector 5 includes SiO 2 Refractive layer 51 and Ti 3 O 5 Refractive layer 52.

[0062] It should be noted that the n-type layer 2, the active layer 3 and the p-type layer 4 stacked on the substrate 1 can be made of gallium nitride material, aluminum indium gallium phosphide material or aluminum indium phosphide material, and the present disclosure does not limit this. In the present disclosure, an epitaxial wafer in which the n-type layer 2, the active layer 3 and the p-type layer 4 are all made of gallium nitride materials is described and illustrated.

[0063] Optionally, the n-type layer 2 may be an n-type GaN layer. The thickness of the n-type GaN layer may be 0.5 to 3 micrometers, which can ensure the quality of the n-type GaN layer.

[0064] For example, the active layer 3 may include GaN barrier layers and InGaN well layers that are alternately stacked. The thickness of the GaN barrier layers may be 8-15 nm, and the thickness of the InGaN well layers may be 1.5-3 nm.

[0065] Optionally, the p-type layer 4 may be a p-type GaN layer, the p-type GaN layer may be doped with Mg, and the thickness of the p-type GaN layer may be 50-80 nm. The obtained p-type GaN layer has good overall quality.

[0066] It should be noted that in other implementations provided in the present disclosure, similar structures such as a buffer layer, a stress release layer, a shallow well layer, a current blocking layer, an electron blocking layer, etc. may be further provided in the light-emitting diode epitaxial wafer, and the present disclosure does not limit this. The Bragg reflector 5 may actually be provided between the n-type layer 2 and the substrate 1 of the light-emitting diode epitaxial wafer, and the growth steps of the Bragg reflector 5 provided in the present disclosure may also be used to improve the quality and reflective efficiency of the final Bragg reflector 5, and the present disclosure does not limit this.

[0067] For ease of understanding, here is provided Figure 3 and Figure 4 , Figure 3 is a schematic diagram of the film state of the Bragg reflector in the prior art provided by the embodiment of the present disclosure, Figure 4 is a schematic diagram of the film state of the Bragg reflector provided by the embodiment of the present disclosure, Figure 4 The film layer of the Bragg reflector in Figure 2 The structure of the Bragg reflector in . Figure 3 and Figure 4It can be seen that the clarity and particles between the film layers of the Bragg reflector provided in the present disclosure are much smaller than the clarity and particles between the film layers of the Bragg reflector in the prior art.

[0068] Figure 5 is a flow chart of another method for preparing a light-emitting diode epitaxial wafer with a Bragg reflector provided in an embodiment of the present disclosure, with reference to Figure 5 It can be seen that the method for preparing a light-emitting diode epitaxial wafer with a Bragg reflector provided in the present disclosure may also include:

[0069] S201: Evaporating multiple SiO at multiple evaporation rates 2 Test layer; Get each SiO 2 The SiO of the test layer 2 Test layer roughness; multiple SiO 2 The test layer was etched and multiple SiO 2 Test layer corrosion rate; according to multiple SiO 2 Test layer roughness and multiple SiO 2 The corrosion rate of the test layer determines the SiO 2 The first relationship curve between the corrosion rate and the roughness of the material; according to the first relationship curve, the slowest corrosion rate SiO 2 The evaporation rate corresponding to the test layer is the first evaporation rate.

[0070] In determining SiO 2 Before the first evaporation rate of the refractive layer, the SiO 2 The first relationship curve between the corrosion rate and roughness of the material is SiO 2 The corrosion rate of the material is related to the roughness, so there is no need to calculate the SiO 2 The test layers are all tested for roughness. According to the first relationship curve, the SiO 2 The corrosion rate of the material is used to determine the SiO 2 The roughness of the material can be reduced. 2 The evaporation rate of the refractive layer most suitable for the Bragg reflector can be determined in a relatively convenient and rapid manner.

[0071] It should be noted that the roughness detection of crystal materials requires a relatively accurate roughness analyzer, which has a high cost.

[0072] For example, each SiO 2 The thickness of the test layer may be 85 nm to 130 nm.

[0073] Each SiO 2When the thickness of the test layer is within the above range, relatively stable corrosion rate data can be obtained without excessively increasing the test cost.

[0074] It should be noted that the corrosion rate can be obtained by dividing the thickness change before and after immersion by the immersion time.

[0075] Optionally, multiple SiO 2 The evaporation rate of the test layer increases in an incremental manner, and the two adjacent SiO 2 The difference in evaporation rate between the test layers is 3A / S.

[0076] The test accuracy of the first relationship curve can be improved.

[0077] It should be noted that two adjacent SiO 2 The test layer is two SiO 2 Experimental layer.

[0078] Optionally, multiple SiO 2 The test layer was etched and multiple SiO 2 Test layer corrosion rate, including:

[0079] NH 4 F. HF and water solution corrodes SiO 2 Test layer, NH 4 The ratio of F and HF is 20:1 respectively.

[0080] The above ratio solution was used to treat SiO 2 The material is corroded to facilitate the determination of SiO 2 The corrosion rate of the material can be easily observed with the naked eye.

[0081] For example, each SiO 2 The test layer was immersed in the ratio solution for 120s to 200s. 2 The test layer is immersed in the ratio solution at a temperature of 20 to 30 degrees Celsius. 2 The test layers were corroded to a certain thickness.

[0082] For ease of understanding, here is provided Figure 6 , Figure 6 is a schematic diagram of a first relationship curve provided by an embodiment of the present disclosure, with reference to Figure 6 It can be seen that SiO 2 Corrosion rate of materials and SiO 2 The roughness of the material is positively correlated. Figure 6 The vertical axis is SiO 2 Data on the corrosion rate of materials, Figure 6The horizontal axis is SiO 2 Material roughness data. It should be noted that Figure 6 The black dots in the figure are SiO 2 Specific data corresponding to the material, Figure 6 The curve in FIG. 1 is the first relationship curve obtained after fitting the black circular points.

[0083] S202: Evaporating multiple Ti at multiple evaporation rates 3 O 5 Experimental layer; get each Ti 3 O 5 Ti of the test layer 3 O 5 Test layer roughness; multiple Ti 3 O 5 The test layer was corroded and multiple Ti 3 O 5 Test layer corrosion rate; according to multiple Ti 3 O 5 Test layer roughness and multiple Ti 3 O 5 The corrosion rate of the test layer is determined by 3 O 5 The second relationship curve between the corrosion rate and roughness of the material; Determine the slowest corrosion rate Ti according to the second relationship curve 3 O 5 The evaporation rate corresponding to the test layer is the second evaporation rate.

[0084] In step S202, the variation trend of the second relationship curve can be referred to Figure 6 The variation trend of the first relationship curve shown in FIG. 1 is not described here in detail. 3 O 5 The proportioning solution of the test layer can refer to the proportioning solution in step S201, which will not be described again here.

[0085] S203: providing a substrate.

[0086] The substrate can be a sapphire substrate, which is easy to realize and manufacture.

[0087] Optionally, step S203 may further include: treating the surface of the substrate for growing the epitaxial layer for 5 to 6 minutes under a hydrogen atmosphere.

[0088] For example, when processing the surface of the substrate for growing the epitaxial layer, the temperature of the reaction chamber may be 1000-1100° C., and the pressure of the reaction chamber may be 200-500 torr.

[0089] S204: growing an n-type layer on the substrate.

[0090] Optionally, the growth pressure of the n-type GaN layer may be 200-600 Torr, and the growth temperature of the n-type GaN layer may be 1000-1100° C.

[0091] S205: growing an active layer on the n-type layer.

[0092] The active layer includes alternately stacked GaN barrier layers and InGaN well layers. The growth temperature of the InGaN well layer can be 760-780° C., and the growth temperature of the GaN barrier layer can be 860-890° C. The quality of the active layer grown under these conditions is good, and the luminous efficiency of the light-emitting diode can be guaranteed.

[0093] S206: growing a p-type layer on the active layer.

[0094] Optionally, the growth pressure of the p-type GaN layer may be 200-600 Torr, and the growth temperature of the p-type GaN layer may be 940-980° C.

[0095] S207: placing the substrate in a pure nitrogen environment with a constant temperature and humidity and leaving it to stand.

[0096] Optionally, the substrate is placed in a pure nitrogen environment with a temperature of 21° C. to 25° C. and a humidity of less than 15% to stand.

[0097] The purity of the substrate and the epitaxial layer evaporated on the substrate can be ensured, and the influence of impurities on the Bragg reflector during the growth process can be reduced.

[0098] S208: Alternately evaporate multiple SiO 2 Refractive layer and Ti 3 O 5 Refractive layer to obtain Bragg reflector, SiO 2 The evaporation rate of the refractive layer is the first evaporation rate to obtain a SiO2 layer with a surface roughness of 0.5 to 0.8 nm. 2 Refractive layer, Ti 3 O 5 The evaporation rate of the refractive layer is the second evaporation rate to obtain a Ti with a surface roughness of 1.0 to 1.1 nm. 3 O 5 Refraction layer.

[0099] It should be noted that step S208 can refer to Figure 1 The step S102 of the method for preparing a light emitting diode epitaxial wafer with a Bragg reflector is shown in FIG. 1 , so the step S208 will not be described in detail here.

[0100] It should be noted that in the embodiments of the present disclosure, Veeco K 465i or C4 or RB MOCVD (Metal Organic Chemical Vapor Deposition) equipment is used to realize the LED growth method. 2 (Hydrogen) or high purity N 2 (nitrogen) or high purity H 2 and high purity N 2 A mixed gas of high purity NH 3 As the N source, trimethylgallium (TMGa) and triethylgallium (TEGa) as the gallium source, trimethylindium (TMIn) as the indium source, silane (SiH 4 ) as N-type dopant, trimethylaluminum (TMAl) as aluminum source, bis(cyclopentadienyl)magnesium (CP 2 Mg) as a P-type dopant.

[0101] The above description does not limit the present disclosure in any form. Although the present disclosure has been disclosed as above through the embodiments, it is not used to limit the present disclosure. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present disclosure. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present disclosure without departing from the content of the technical solution of the present disclosure still falls within the scope of the technical solution of the present disclosure.

Claims

1. A method for preparing a light emitting diode epitaxial wafer having a Bragg reflector, characterized in that: The method for preparing the light emitting diode epitaxial wafer with a Bragg reflector comprises: An n-type layer, an active layer and a p-type layer are sequentially grown on a substrate; A plurality of SiO2 refractive layers and Ti3O5 refractive layers are alternately evaporated on the p-type layer to obtain a Bragg reflector, wherein the evaporation rate of the SiO2 refractive layer is a first evaporation rate to obtain a SiO2 refractive layer with a surface roughness of 0.5-0.8 nm, and the evaporation rate of the Ti3O5 refractive layer is a second evaporation rate to obtain a Ti3O5 refractive layer with a surface roughness of 1.0-1.1 nm; The first evaporation rate of the SiO2 refractive layer is 4-6 angstroms / second, and the second evaporation rate of the Ti3O5 refractive layer is 1.8-2.2 angstroms / second; The evaporation voltage of the SiO2 refractive layer is 1150-1250V, and when the ion beam current for growing the SiO2 refractive layer is 1150-1250mA, the O2 flux for growing the SiO2 refractive layer is 45-55sccm.

2. The method for preparing a light emitting diode epitaxial wafer with a Bragg reflector according to claim 1, characterized in that: The evaporation voltage of the Ti3O5 refractive layer is 1350-1450V, the ion beam current for growing the Ti3O5 refractive layer is 1350-1450mA, the O2 flux for growing the Ti3O5 refractive layer is 80-90sccm, and the Ar flux for growing the Ti3O5 refractive layer is 10-15sccm.

3. The method for preparing a light emitting diode epitaxial wafer with a Bragg reflector according to claim 1, characterized in that: The coating temperature of the SiO2 refractive layer is 120°C-140°C.

4. The method for preparing a light emitting diode epitaxial wafer with a Bragg reflector according to claim 1, characterized in that: The evaporation temperature of the Ti3O5 refractive layer is 120°C-140°C.

5. The method for preparing a light emitting diode epitaxial wafer with a Bragg reflector according to claim 1, characterized in that: The method for preparing the light emitting diode epitaxial wafer with a Bragg reflector further comprises: Depositing a plurality of SiO2 test layers at a plurality of evaporation rates; Obtaining the surface roughness of the SiO2 test layer of each of the SiO2 test layers; Corroding a plurality of the SiO2 test layers and obtaining a plurality of SiO2 test layer corrosion rates; Determine a first relationship curve between the corrosion rate and the surface roughness of the SiO2 material according to the surface roughness of the plurality of SiO2 test layers and the corrosion rates of the plurality of SiO2 test layers; The evaporation rate corresponding to the SiO2 test layer having the slowest corrosion rate is determined according to the first relationship curve as the first evaporation rate.

6. The method for preparing a light emitting diode epitaxial wafer with a Bragg reflector according to claim 5, characterized in that: The etching of the plurality of SiO2 test layers and obtaining the etching rates of the plurality of SiO2 test layers comprises: The SiO2 test layer is corroded with a solution of NH4F, HF and water, wherein the ratio of NH4F to HF in the solution is 20:

1.

7. The method for preparing a light emitting diode epitaxial wafer with a Bragg reflector according to claim 1, characterized in that: The method for preparing the light emitting diode epitaxial wafer with a Bragg reflector further comprises: After the n-type layer, active layer and p-type layer are sequentially grown on the substrate, and before a plurality of SiO2 refractive layers and Ti3O5 refractive layers are alternately evaporated on the p-type layer to obtain a Bragg reflector, the substrate is placed in a pure nitrogen environment with constant temperature and humidity.

8. The method for preparing a light emitting diode epitaxial wafer with a Bragg reflector according to claim 7, characterized in that: The substrate is placed in a pure nitrogen environment with a temperature of 21° C. to 25° C. and a humidity of less than 15%.

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