Method for preparing epitaxial wafer with improved doping efficiency and epitaxial growth apparatus

Abstract

The disclosure provides an epitaxial wafer preparation method and an epitaxial growth device for improving doping efficiency, and belongs to the technical field of epitaxial preparation. Cp2Mg enters the reaction cavity through a magnesium source pipeline, and the side wall of the magnesium source pipeline is connected with an auxiliary pushing pipeline. In the process of solid Cp2Mg entering the reaction cavity through the magnesium source pipeline, a growth pushing gas is introduced into the magnesium source pipeline from the auxiliary pushing pipeline, and the growth pushing gas is an inert gas. Without increasing the doping amount of Cp2Mg, the unit flow rate of Cp2Mg is increased, the flow and reaction of Cp2Mg in the reaction cavity are promoted, the uniform distribution of Cp2Mg is ensured, and the rapid growth of the p-type GaN layer is promoted. The more uniform distribution of Cp2Mg can improve the doping efficiency of Mg elements in the p-type GaN layer and the uniformity of the distribution to improve the radiation recombination efficiency of electrons and holes in the finally obtained epitaxial wafer.

Description

Technical Field

[0001] The present disclosure relates to the technical field of epitaxial preparation, and in particular to an epitaxial wafer preparation method and epitaxial growth equipment for improving doping efficiency. Background Art

[0002] Light-emitting diodes (LEDs) are widely used light-emitting devices, commonly found in traffic lights, interior and exterior automotive lighting, urban lighting, and landscape lighting. LED epitaxial wafers are the fundamental structure used to manufacture LEDs. These wafers typically consist of a substrate, followed by an n-type GaN layer, a light-emitting layer, and a p-type GaN layer stacked on top of the substrate. Electrons generated in the n-type GaN layer and holes generated in the p-type GaN layer, driven by current, enter the light-emitting layer, where they recombine and emit light.

[0003] Mg doping is required in the p-type GaN layer to ensure that the p-type GaN layer can provide sufficient holes. The Mg doped in the p-type GaN layer comes from Cp2Mg introduced into the reaction chamber during the growth of the p-type GaN layer. Since Cp2Mg is in solid state, the efficiency of Cp2Mg being brought to the reaction chamber by the carrier gas is lower than that of a liquid metal source. At the same time, the activation efficiency of Cp2Mg itself is also relatively low. The superposition effect of the two results in less Mg elements entering the p-type GaN layer, resulting in fewer effective holes in the p-type GaN layer and uneven distribution, which in turn affects the radiation recombination efficiency of electrons and holes. Summary of the Invention

[0004] The present disclosure provides a method for preparing an epitaxial wafer with improved doping efficiency and an epitaxial growth device, which can improve the doping efficiency of Mg in the p-type GaN layer and thus increase the radiative recombination efficiency of electrons and holes in the resulting epitaxial wafer. The technical solution is as follows:

[0005] The present disclosure provides a light-emitting diode epitaxial wafer. The method for preparing the epitaxial wafer with improved doping efficiency includes:

[0006] providing a substrate;

[0007] sequentially growing an n-type GaN layer and a light-emitting layer on the substrate;

[0008] A Ga source, ammonia and Cp2Mg are introduced into the reaction chamber to grow a p-type GaN layer on the light-emitting layer. The Cp2Mg enters the reaction chamber through a magnesium source pipe. The side wall of the magnesium source pipe is connected to an auxiliary push pipe. During the process of the Cp2Mg entering the reaction chamber through the magnesium source pipe, a growth push gas is introduced into the magnesium source pipe from the auxiliary push pipe. The growth push gas is an inert gas.

[0009] Optionally, the ratio of the flow rate of the growth driving gas introduced into the magnesium source pipe from the auxiliary driving pipe to the flow rate of the Cp2Mg entering the reaction chamber through the magnesium source pipe is 1:5 to 1:15.

[0010] Optionally, the flow rate of the growth driving gas introduced into the magnesium source pipeline from the auxiliary driving pipeline is 50 to 300 sccm.

[0011] Optionally, the growth promoting gas is nitrogen or hydrogen or a hydrogen-nitrogen mixture.

[0012] Optionally, the method for preparing an epitaxial wafer with improved doping efficiency further comprises: after growing the light-emitting layer on the n-type GaN layer, introducing a Ga source, ammonia and Cp2Mg into the reaction chamber before growing a p-type GaN layer on the light-emitting layer,

[0013] The Cp2Mg is introduced into the reaction chamber through the magnesium source pipe, and at the same time, an auxiliary driving gas is introduced into the magnesium source pipe through the auxiliary driving pipe.

[0014] Optionally, the flow rate of the auxiliary driving gas is greater than the flow rate of the growth driving gas.

[0015] Optionally, the flow rate of the auxiliary driving gas is 200-500 sccm.

[0016] Optionally, after growing the light-emitting layer on the n-type GaN layer, before introducing Ga source, ammonia and Cp2Mg into the reaction chamber to grow the p-type GaN layer on the light-emitting layer, the Cp2Mg at a flow rate of 500 to 1500 sccm is introduced into the reaction chamber through the magnesium source pipe.

[0017] Optionally, after growing the light-emitting layer on the n-type GaN layer, before introducing Ga source, ammonia and Cp2Mg into the reaction chamber to grow the p-type GaN layer on the light-emitting layer, the Cp2Mg is introduced into the reaction chamber through the magnesium source pipe for 5 to 15 minutes.

[0018] The embodiment of the present disclosure provides an epitaxial growth device, which includes a mounting base, a substrate placement component, and a gas delivery component.

[0019] The mounting seat includes a reaction chamber, the substrate placement component is located in the reaction chamber and is used to place a substrate, the gas delivery component includes a magnesium source delivery pump, a gas delivery pump, a magnesium source pipeline and an auxiliary push pipeline, the magnesium source delivery pump and the gas delivery pump are spaced from the mounting seat, the two ends of the magnesium source pipeline are respectively connected to the reaction chamber and the magnesium source delivery pump, and the two ends of the auxiliary push pipeline are respectively connected to the reaction chamber and the gas delivery pump.

[0020] The technical solutions provided by the embodiments of the present disclosure bring beneficial effects including:

[0021] The deposition and growth of the p-type GaN layer on the light-emitting layer can be achieved by introducing Ga source, ammonia and Cp2Mg into the reaction chamber. During the growth of the p-type GaN layer, Cp2Mg enters the reaction chamber through the magnesium source pipe, and the side wall of the magnesium source pipe is connected to an auxiliary driving pipe. In the process of solid Cp2Mg entering the reaction chamber through the magnesium source pipe, a growth driving gas is introduced into the magnesium source pipe from the auxiliary driving pipe, and the growth driving gas is an inert gas. The growth driving gas, which is an inert gas, can increase the unit flow rate of Cp2Mg without increasing the doping amount of Cp2Mg, promote the flow and reaction of Cp2Mg in the reaction chamber, so as to ensure the uniform distribution of Cp2Mg and promote the entry of Mg element into the p-type GaN layer, and the growth driving gas will not affect the reaction of Ga source and ammonia in the reaction chamber, which can effectively improve the uniform distribution of Mg element in the p-type GaN layer. Furthermore, the growth-propelling gas enters the magnesium source pipe from the sidewall through the auxiliary propulsion pipe. A certain flow rate difference exists between the Cp2Mg on either radial side of the magnesium source pipe, allowing the Cp2Mg to better adapt to the spiral flow field within the reaction chamber and achieve a more uniform distribution of the Cp2Mg. This more uniform distribution of the Cp2Mg improves the doping efficiency and distribution uniformity of the Mg element in the p-type GaN layer, thereby increasing the radiative recombination efficiency of electrons and holes in the resulting epitaxial wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. 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 any creative work.

[0023] Figure 1 is a simplified structural diagram of an epitaxial growth device provided by an embodiment of the present disclosure;

[0024] Figure 2 Schematic diagram of the positional relationship between the magnesium source pipe and the auxiliary propulsion pipe provided in an embodiment of the present disclosure;

[0025] Figure 3 This is a flow chart of a method for preparing an epitaxial wafer with improved doping efficiency provided by an embodiment of the present disclosure;

[0026] Figure 4 This is a schematic diagram of an epitaxial wafer structure for improving doping efficiency provided by an embodiment of the present disclosure;

[0027] Figure 5This is a flow chart of another method for preparing an epitaxial wafer with improved doping efficiency provided by an embodiment of the present disclosure;

[0028] Figure 6 This is a schematic diagram of another epitaxial wafer structure for improving doping efficiency provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] 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.

[0030] For ease of understanding, the basic structure of the epitaxial growth equipment used to prepare epitaxial wafers is first described here. Figure 1 This is a simplified schematic diagram of the epitaxial growth device provided by the embodiment of the present disclosure. Figure 1 It can be seen that the embodiment of the present disclosure provides an epitaxial growth device, which includes a mounting base 1, a substrate placement component 2, and a gas delivery component 3. The mounting base 1 includes a reaction chamber 11, the substrate placement component 2 is located in the reaction chamber 11 and is used to place a substrate, and the gas delivery component 3 includes a magnesium source delivery pump 31, a gas delivery pump 32, a magnesium source pipeline 33, and an auxiliary driving pipeline 34. The magnesium source delivery pump 31 and the gas delivery pump 32 are separated from the mounting base 1, and the two ends of the magnesium source pipeline 33 are respectively connected to the reaction chamber 11 and the magnesium source delivery pump 31. The two ends of the auxiliary driving pipeline 34 are respectively connected to the reaction chamber 11 and the gas delivery pump 32.

[0031] The deposition and growth of the p-type GaN layer on the light-emitting layer can be achieved by introducing Ga source, ammonia and Cp2Mg into the reaction chamber 11. During the growth of the p-type GaN layer, Cp2Mg enters the reaction chamber 11 through the magnesium source pipe 33, and the side wall of the magnesium source pipe is connected to the auxiliary driving pipe 34. In the process of solid Cp2Mg entering the reaction chamber 11 through the magnesium source pipe 33, a growth driving gas is introduced into the magnesium source pipe 33 from the auxiliary driving pipe 34, and the growth driving gas is an inert gas. The growth driving gas, which is an inert gas, can increase the unit flow rate of Cp2Mg without increasing the doping amount of Cp2Mg, promote the flow and reaction of Cp2Mg in the reaction chamber 11, so as to ensure the uniform distribution of Cp2Mg and promote the entry of Mg element into the p-type GaN layer, and the growth driving gas will not affect the reaction of Ga source and ammonia in the reaction chamber 11, and can effectively improve the uniform distribution of Mg element in the p-type GaN layer. Furthermore, the growth-propelling gas enters the magnesium source pipe 33 from the sidewall thereof through the auxiliary propulsion pipe 34. A certain flow velocity difference exists between the Cp2Mg on the radial sides of the magnesium source pipe 33, which allows the Cp2Mg to better adapt to the spiral flow field within the reaction chamber 11 and achieves a more uniform distribution of the Cp2Mg. A more uniform distribution of the Cp2Mg can improve the doping efficiency and distribution uniformity of the Mg element in the p-type GaN layer, thereby increasing the radiative recombination efficiency of electrons and holes in the resulting epitaxial wafer.

[0032] It should be noted that in the related art, the flow rate of Cp2Mg entering the reaction chamber 11 through the magnesium source pipe 33 can be changed, but the flow rate of Cp2Mg is usually difficult to change and there is an upper limit to the flow rate. In order to ensure the flow rate, a smaller flow rate of Cp2Mg is introduced into the reaction chamber 11, which may cause Cp2Mg to fail to keep up with the reaction rate of the Ga source and ammonia, resulting in too little Mg in the p-type GaN layer. Sacrificing the flow rate to introduce a larger flow rate of Cp2Mg into the reaction chamber 11 may easily cause the problem of accumulation and uneven distribution of Mg elements in the p-type GaN layer, resulting in the overall quality of the p-type GaN layer finally obtained being not good enough. The increase of the growth-promoting gas in the present disclosure can effectively increase the flow rate of Cp2Mg without reducing the molar mass of Cp2Mg entering the reaction chamber 11, and can also increase the upper limit of the flow rate of Cp2Mg, and can also be applied to the growth of more different materials that need to be doped with Mg.

[0033] It should be noted that different organic metal sources or reaction gases introduced into the reaction chamber 11 may be provided with different pipelines to transport the organic metal sources and reaction gases into the reaction chamber 11. The present disclosure does not impose any limitation on this.

[0034] Figure 2 This is a schematic diagram of the positional relationship between the magnesium source pipeline and the auxiliary propulsion pipeline provided in the embodiment of the present disclosure, with reference to Figure 2It can be seen that one end of the auxiliary pushing pipeline 34 is in communication with the side wall of the magnesium source pipeline 33. For the convenience of understanding, the input end of the magnesium source pipeline 33 and the input end of the auxiliary pushing pipeline 34 are respectively identified as 331 and 341 in Figure 2 It can be seen from Figure 2 that the output end of the auxiliary pushing pipeline 34 is in communication with the side wall of the magnesium source pipeline 33, and the output end of the magnesium source pipeline 33 is in communication with the reaction cavity 11.

[0035] It should be noted that the magnesium source conveying pump 31 and the gas conveying pump 32 can be located in the mounting seat 1 and spaced from the reaction cavity 11, or can be located outside the mounting seat 1 and spaced from the mounting seat 1, which is not limited by the present disclosure. The mounting seat 1 can include a seat body and a box cover, the seat body has a recess therein, and the seat body is hinged to the box cover. When the box cover is closed between the seat body and the seat cover, the box cover and the recess form the reaction cavity 11.

[0036] Optionally, the substrate placing component 2 includes a graphite disc 21 and a driving motor 22. The graphite disc 21 is located in the reaction cavity 11. The graphite disc 21 is generally columnar, and one end face of the graphite disc 21 has a plurality of substrate placing recesses. The end face of the graphite disc 21 having the plurality of substrate placing recesses is opposite to the output ends of the magnesium source pipeline 33 and the auxiliary pushing pipeline 34. The driving motor 22 is spaced from the reaction cavity 11, and an output shaft of the driving motor 22 is located in the reaction cavity 11. The output shaft of the driving motor 22 is coaxially connected to the graphite disc 21.

[0037] During the preparation of the epitaxial wafer, the substrate can be placed in the substrate placing recess. The substrate is supported by the graphite disc 21 as a whole. The driving motor 22 can drive the graphite disc 21 to rotate through the output shaft to ensure that the substrate in each substrate placing recess can react with the organic metal source and the reaction gas in the reaction cavity 11 to form a relatively uniform and high-quality epitaxial wafer on each substrate.

[0038] In other implementations provided by the present disclosure, the epitaxial growth device can further include other structures such as a heating component or a condensing component in addition to the substrate placing component 2 and the gas conveying component 3, which is not limited by the present disclosure. The heating component can include a heating wire located between the graphite disc 21 and the bottom of the reaction cavity 11, and the heating wire can be supported on the bottom of the reaction cavity 11. The condensing component can include some condensing water pipes added to the side wall of the reaction cavity 11 and a pump structure for controlling the flow of condensing water in the condensing water pipes, which is not limited by the present disclosure.

[0039] Figure 3 is a flow chart of an epitaxial wafer preparation method for improving doping efficiency provided by an embodiment of the present disclosure, referring to Figure 3 It can be seen that the present disclosure provides a light emitting diode epitaxial wafer, and an epitaxial wafer preparation method for improving doping efficiency includes:

[0040] S101: providing a substrate.

[0041] S102: Growing an n-type GaN layer and a light-emitting layer in sequence on the substrate.

[0042] S103: Ga source, ammonia and Cp2Mg are introduced into the reaction chamber to grow a p-type GaN layer on the light-emitting layer. Cp2Mg enters the reaction chamber through a magnesium source pipe. The side wall of the magnesium source pipe is connected to an auxiliary push pipe. In the process of Cp2Mg entering the reaction chamber through the magnesium source pipe, a growth push gas is introduced into the magnesium source pipe from the auxiliary push pipe. The growth push gas is an inert gas.

[0043] The deposition and growth of the p-type GaN layer on the light-emitting layer can be achieved by introducing Ga source, ammonia and Cp2Mg into the reaction chamber. During the growth of the p-type GaN layer, Cp2Mg enters the reaction chamber through the magnesium source pipe, and the side wall of the magnesium source pipe is connected to an auxiliary driving pipe. In the process of solid Cp2Mg entering the reaction chamber through the magnesium source pipe, a growth driving gas is introduced into the magnesium source pipe from the auxiliary driving pipe, and the growth driving gas is an inert gas. The growth driving gas, which is an inert gas, can increase the unit flow rate of Cp2Mg without increasing the doping amount of Cp2Mg, promote the flow and reaction of Cp2Mg in the reaction chamber, so as to ensure the uniform distribution of Cp2Mg and promote the entry of Mg element into the p-type GaN layer, and the growth driving gas will not affect the reaction of Ga source and ammonia in the reaction chamber, which can effectively improve the uniform distribution of Mg element in the p-type GaN layer. Furthermore, the growth-propelling gas enters the magnesium source pipe from the sidewall through the auxiliary propulsion pipe. A certain flow rate difference exists between the Cp2Mg on either radial side of the magnesium source pipe, allowing the Cp2Mg to better adapt to the spiral flow field within the reaction chamber and achieve a more uniform distribution of the Cp2Mg. This more uniform distribution of the Cp2Mg improves the doping efficiency and distribution uniformity of the Mg element in the p-type GaN layer, thereby increasing the radiative recombination efficiency of electrons and holes in the resulting epitaxial wafer.

[0044] Optionally, in step S103, the ratio of the flow rate of the growth driving gas introduced from the auxiliary driving pipe into the magnesium source pipe to the flow rate of Cp2Mg entering the reaction chamber through the magnesium source pipe is 1:5 to 1:15.

[0045] The ratio of the flow rate of the growth driving gas introduced into the magnesium source pipeline from the auxiliary driving pipeline to the flow rate of Cp2Mg entering the reaction chamber through the magnesium source pipeline is within the above range, which can ensure that the flow rate of the growth driving gas is relatively reasonable, effectively promote the flow and uniform distribution of Cp2Mg, and ensure a stable reaction between Cp2Mg and the organic metal source or ammonia in the reaction chamber, thereby improving the quality of the p-type GaN layer finally obtained.

[0046] Optionally, the flow rate of the growth pushing gas introduced into the magnesium source pipe through the auxiliary pushing pipe is 50-300 sccm.

[0047] The flow rate of the growth pushing gas introduced into the magnesium source pipe through the auxiliary pushing pipe is within the above range, which can effectively promote the flow and uniform distribution of Cp2Mg, and effectively improve the quality of the finally obtained p-type GaN layer and the doping and uniform distribution of the Mg element in the p-type GaN layer.

[0048] In other implementations provided by the present disclosure, the flow rate of the growth pushing gas introduced into the magnesium source pipe through the auxiliary pushing pipe can also be 100-200 sccm. The quality of the obtained p-type GaN layer can be further improved and the doping efficiency of Mg in the obtained p-type GaN layer can be ensured.

[0049] Optionally, in step S103, the growth pushing gas is nitrogen or hydrogen or hydrogen-nitrogen mixed gas.

[0050] The growth pushing gas is the above gas, which can ensure the stable pushing of the growth pushing gas and ensure that the growth pushing gas will not have a large impact on other reactions in the reaction chamber.

[0051] Illustratively, in step S103, the flow rate of Cp2Mg entering the reaction chamber through the magnesium source pipe can be 500-1500 sccm, the flow rate of the Ga source introduced into the reaction chamber can be 50-150 sccm, and the flow rate of ammonia introduced into the reaction chamber can be 30-80 sccm.

[0052] During the growth of the p-type GaN layer, the flow rates of the Ga source, ammonia and Cp2Mg are within the above ranges, which can ensure that the quality of the obtained p-type GaN layer is good, and can also be used to grow more p-type GaN layers of different thickness specifications.

[0053] It should be noted that the growth pushing gas mainly enters the magnesium source pipe, and the introduction of the growth pushing gas has no effect on the pressure and temperature of the Cp2Mg introduced into the magnesium source pipe. The temperature and pressure of the Cp2Mg introduced into the reaction chamber can be 850-950℃ or 100-500 torr, respectively. The present disclosure does not limit this.

[0054] Figure 4 is a schematic diagram of an epitaxial wafer structure for improving doping efficiency provided by an embodiment of the present disclosure, Figure 4 The epitaxial wafer structure shown in Figure 3 The epitaxial wafer structure prepared by the epitaxial wafer preparation method for improving doping efficiency shown in Figure 4 It can be seen that the epitaxial wafer includes a substrate 10 and an n-type GaN layer 20, a light-emitting layer 30 and a p-type GaN layer 40 which are sequentially stacked on the substrate 10.

[0055] Figure 5 is another flow chart of the method for preparing an epitaxial wafer with improved doping efficiency provided by the embodiments of the present disclosure, referring to Figure 5 It can be seen that the method for preparing an epitaxial wafer with improved doping efficiency can comprise:

[0056] 201: providing a substrate.

[0057] The substrate can be a sapphire substrate. It is easy to implement and manufacture.

[0058] Optionally, step S201 can further comprise: treating the substrate under a hydrogen atmosphere for 5-6 minutes for growing the surface of the epitaxial layer.

[0059] Illustratively, when the substrate is treated for growing the surface of the epitaxial layer, the temperature of the reaction chamber can be 1000-1100℃, and the pressure of the reaction chamber can be 200-500 torr.

[0060] S202: growing a GaN buffer layer on the substrate.

[0061] Illustratively, the growth temperature of the GaN buffer layer can be 530-560℃, and the pressure can be 200-500mtorr. The obtained GaN buffer layer has good quality.

[0062] S203: growing an undoped GaN layer on the GaN buffer layer.

[0063] The thickness of the undoped GaN layer can be 0.5-3um.

[0064] Illustratively, the growth temperature of the undoped GaN layer can be 1000-1100℃, and the growth pressure is controlled at 100-300 torr. The obtained undoped GaN layer has good quality.

[0065] S204: growing an n-type GaN layer on the undoped GaN layer.

[0066] The growth temperature of the n-type GaN layer is 1000-1100℃, and the growth pressure is controlled at 100-300 torr.

[0067] S205: growing a light-emitting layer on the n-type GaN layer.

[0068] The light-emitting layer can comprise InGaN well layers and GaN barrier layers alternately grown. The pressure of the reaction chamber is controlled at 200 torr. When the InGaN well layer is grown, the temperature of the reaction chamber is 760-780℃. When the GaN barrier layer is grown, the temperature of the reaction chamber is 860-890℃. The obtained light-emitting layer has good quality.

[0069] S206: growing an AlGaN electron blocking layer on the light-emitting layer.

[0070] The AlGaN electron blocking layer can be grown at a temperature of 800-1000°C and a pressure of 100-300 Torr. The AlGaN electron blocking layer grown under these conditions has good quality, which is beneficial for improving the luminous efficiency of the light-emitting diode.

[0071] S207: Cp2Mg is introduced into the reaction chamber through the magnesium source pipeline, and at the same time, an auxiliary propulsion gas is introduced into the magnesium source pipeline through the auxiliary propulsion pipeline.

[0072] Before growing the p-type GaN layer, an Mg source is first introduced into the reaction chamber to ensure that there is a certain amount of Mg element in the reaction chamber before the p-type GaN layer grows, so as to promote the entry of Mg element into the p-type GaN layer. The increase of auxiliary driving gas can promote the uniform distribution of Mg element, thereby ensuring the uniform distribution of Mg element in the final p-type GaN layer, thereby ensuring that the p-type GaN layer can provide a relatively uniform space and ensure the uniform light emission of the epitaxial wafer.

[0073] For example, the type of the auxiliary driving gas may be the same as the type of the growth driving gas, which facilitates the preparation of epitaxial wafers.

[0074] In other implementations provided by the present disclosure, the type of the auxiliary driving gas may be different from the type of the growth driving gas, and the present disclosure does not impose any limitation on this.

[0075] Optionally, the flow rate of the auxiliary driving gas is greater than the flow rate of the growth driving gas.

[0076] The flow rate of the auxiliary driving gas is greater than the flow rate of the growth driving gas, which can maximize the uniform distribution of the Mg element in the reaction chamber and ensure the uniform growth of the obtained p-type GaN layer.

[0077] Optionally, the flow rate of the auxiliary driving gas is 200-500 sccm.

[0078] When the flow rate of the auxiliary driving gas is within the above range, it can effectively promote the uniform distribution of the Mg element without excessively increasing the overall preparation cost of the epitaxial wafer.

[0079] In other implementations provided by the present disclosure, the flow rate of the auxiliary driving gas may also be 200-400 sccm, which can also effectively promote the uniform distribution of the Mg element.

[0080] Optionally, in step S207, Cp2Mg is introduced into the reaction chamber through the magnesium source pipe at a flow rate of 500-1500 sccm. This ensures that a suitable amount of Cp2Mg is introduced, uniform distribution of the Mg element is ensured, and good growth quality of the resulting p-type GaN layer is ensured.

[0081] Optionally, in step S207, the time for introducing Cp2Mg into the reaction chamber through the magnesium source pipe is 5 to 15 minutes, which can ensure the uniform distribution of the Mg element and effectively improve the uniform distribution of the Mg element in the final p-type GaN layer.

[0082] S208: introducing a Ga source, ammonia, and Cp2Mg into the reaction chamber to grow a p-type GaN layer on the AlGaN electron blocking layer.

[0083] The growth conditions of the p-type GaN layer and multiple insertion layers can be referred to Figure 3 The step S103 shown in FIG is omitted for brevity.

[0084] S209: growing a p-type contact layer on the p-type GaN layer.

[0085] Optionally, the growth pressure of the p-type contact layer may be 100-300 Torr, and the growth temperature of the p-type contact layer may be 800-1000°C.

[0086] It should be noted that Figure 5 The method for preparing the light emitting diode epitaxial wafer shown in Figure 3 The light-emitting diode preparation method shown in provides a more detailed growth method of light-emitting diode epitaxial wafers.

[0087] The structure of the light emitting diode epitaxial wafer after executing step S209 can be seen in Figure 6 .

[0088] It should be noted that in the embodiments of the present disclosure, high-purity H2 (hydrogen) or high-purity N2 (nitrogen) or a mixed gas of high-purity H2 and high-purity N2 is used as the carrier gas, high-purity NH3 is used as the N source, trimethylgallium (TMGa) and triethylgallium (TEGa) are used as gallium sources, trimethylindium (TMIn) is used as the indium source, silane (SiH4) is used as the N-type dopant, trimethylaluminum (TMAl) is used as the aluminum source, and bis(cyclopentadienyl)magnesium (CP2Mg) is used as the P-type dopant.

[0089] Figure 6 This is a schematic diagram of another epitaxial wafer structure for improving doping efficiency provided by an embodiment of the present disclosure. Figure 6 The epitaxial wafer structure shown in Figure 5 The epitaxial wafer preparation method shown in is prepared, reference Figure 6 It can be seen that in another implementation provided by the present disclosure, the light-emitting diode epitaxial wafer may include a substrate 10 and a GaN buffer layer 50, an undoped GaN layer 60, an n-type GaN layer 20, a light-emitting layer 30, an AlGaN electron blocking layer 70, a p-type GaN layer 40 and a p-type contact layer 80 grown on the substrate 10.

[0090] Optionally, the substrate 10 can be a sapphire substrate 10. It is easy to make and obtain.

[0091] Optionally, the thickness of the GaN buffer layer 50 can be 10-30 nm. It can reduce the lattice mismatch between the n-type GaN layer 20 and the substrate 10, and ensure the crystal quality of the epitaxial layer.

[0092] Illustratively, the thickness of the undoped GaN layer 60 can be 1-3.5 μm. In this case, the quality of the obtained light emitting diode epitaxial wafer is better.

[0093] In an implementation provided by the present disclosure, the thickness of the undoped GaN layer 60 can also be 1 μm. The present disclosure does not limit this.

[0094] Optionally, the doping element of the n-type GaN layer 20 can be Si, and the doping concentration of the Si element can be 1×1018-1×1020cm-3. The quality of the n-type GaN layer 20 as a whole is better. 18 19 -3 The quality of the n-type GaN layer 20 as a whole is better.

[0095] Illustratively, the thickness of the n-type GaN layer 20 can be 2-3 μm. The quality of the n-type GaN layer 20 as a whole is better.

[0096] In an implementation provided by the present disclosure, the thickness of the n-type GaN layer 20 can be 2 μm. The present disclosure does not limit this.

[0097] Optionally, the light emitting layer 30 can include InGaN well layers and GaN barrier layers which are alternately stacked. It is easy to make and obtain.

[0098] Optionally, the Al component in the AlGaN electron blocking layer 70 can be 0.15-0.25. The effect of blocking electrons is better.

[0099] Optionally, the p-type GaN layer 40 can be doped with Mg.

[0100] Illustratively, the thickness of the p-type contact layer 80 can be 15 nm.

[0101] It should be noted that, Figure 6 The epitaxial wafer structure shown in the present disclosure is relatively Figure 4 The epitaxial wafer structure shown in the present disclosure adds the electron blocking layer 70 between the light emitting layer 30 and the p-type GaN layer 40, and the p-type contact layer 80 is also grown on the p-type GaN layer 40. The quality and light emitting efficiency of the obtained epitaxial wafer are better.

[0102] ​​The above description 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 within the scope of the technical solutions of the present disclosure to obtain equivalent embodiments with equivalent changes, but as long as the changes do not deviate from the technical solutions 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 are still within the scope of the technical solutions of the present disclosure.

Claims

1. A method for preparing an epitaxial wafer with improved doping efficiency, characterized in that: The method for preparing an epitaxial wafer with improved doping efficiency comprises: providing a substrate; sequentially growing an n-type GaN layer and a light-emitting layer on the substrate; Cp2Mg is introduced into the reaction chamber through the magnesium source pipe, and at the same time, an auxiliary driving gas is introduced into the magnesium source pipe through the auxiliary driving pipe; Ga source, ammonia and Cp2Mg are introduced into the reaction chamber to grow a p-type GaN layer on the light-emitting layer. The Cp2Mg enters the reaction chamber through a magnesium source pipe. The side wall of the magnesium source pipe is connected to an auxiliary push pipe. In the process of the Cp2Mg passing through the magnesium source pipe and entering the reaction chamber, a growth push gas is introduced into the magnesium source pipe from the auxiliary push pipe. The growth push gas is an inert gas. The flow rate of the auxiliary push gas is greater than the flow rate of the growth push gas. When the p-type GaN layer grows, the flow rate of the Cp2Mg is 500~1500sccm.

2. The method for preparing an epitaxial wafer with improved doping efficiency according to claim 1, wherein: The ratio of the flow rate of the growth driving gas introduced into the magnesium source pipe from the auxiliary driving pipe to the flow rate of the Cp2Mg entering the reaction chamber through the magnesium source pipe is 1:5-1:

15.

3. The method for preparing an epitaxial wafer with improved doping efficiency according to claim 1, wherein: The flow rate of the growth driving gas introduced into the magnesium source pipe from the auxiliary driving pipe is 50-300 sccm.

4. The method for preparing an epitaxial wafer with improved doping efficiency according to any one of claims 1 to 3, characterized in that: The growth promoting gas is nitrogen or hydrogen or a hydrogen-nitrogen mixed gas.

5. The method for preparing an epitaxial wafer with improved doping efficiency according to any one of claims 1 to 3, characterized in that: The flow rate of the auxiliary driving gas is 200-500 sccm.

6. The method for preparing an epitaxial wafer with improved doping efficiency according to any one of claims 1 to 3, characterized in that: After growing the light-emitting layer on the n-type GaN layer, the Cp2Mg with a flow rate of 500-1500 sccm is introduced into the reaction chamber through the magnesium source pipe before introducing Ga source, ammonia and Cp2Mg into the reaction chamber to grow the p-type GaN layer on the light-emitting layer.

7. The method for preparing an epitaxial wafer with improved doping efficiency according to any one of claims 1 to 3, characterized in that: After growing the light-emitting layer on the n-type GaN layer, before introducing Ga source, ammonia and Cp2Mg into the reaction chamber to grow the p-type GaN layer on the light-emitting layer, the Cp2Mg is introduced into the reaction chamber through the magnesium source pipe for 5 to 15 minutes.

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