Epitaxial wafer of mini led with low gate current effect and growth method thereof

Abstract

The present application relates to the technical field of LED chip, and particularly relates to an epitaxial wafer of Mini LED with low GTO effect and a growth method thereof. The epitaxial wafer of Mini LED with low GTO effect comprises a buffer layer, a U-shaped GaN layer, an N-type GaN layer, a multi-quantum well active region layer and a P-type GaN layer which are sequentially grown on a substrate. The multi-quantum well active region layer comprises a defect inducing layer, a Si-doped AlGaN layer and a multi-quantum well light emitting layer which are sequentially grown on the N-type GaN layer. The epitaxial wafer of Mini LED avoids strong GTO effect and improves the brightness consistency of Mini LED by setting the defect inducing layer after the N-type GaN layer and setting the Si-doped AlGaN layer after the defect inducing layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED chip, and particularly relates to an epitaxial wafer of Mini LED with low thyristor effect and a growth method thereof. BACKGROUND

[0002] Modern society has entered the information age and is developing towards intelligence, and display is a key link to realize information exchange and intelligence. In the current numerous display technologies, Mini LED (chip size less than 200 mu m) display technology is regarded as the next generation display technology and will inevitably occupy a dominant position. A Chinese patent with the publication number CN115799423B discloses an epitaxial wafer for Mini-LED, which comprises a substrate and a buffer layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer and a P-GaN layer arranged on the substrate in sequence. Compared with traditional LED, Mini LED has smaller volume, more delicate display effect, higher brightness, color saturation and contrast.

[0003] However, due to the large lattice mismatch and thermal mismatch between gallium nitride material and sapphire substrate in Mini LED, there is a large stress in epitaxial growth, which further produces V-type defects, so that in the process of crystal growth, the PN layer appears to be staggered due to uneven thickness, forming a thyristor effect.

[0004] The thyristor effect is a description of the capacitance between the PN junction of the diode. The presence of the thyristor will increase the on-voltage of the diode, making it difficult to light up the light-emitting diode. Once the on-voltage is broken through, the forward voltage of the diode will slowly decrease from the on-voltage as the current increases, and then the normal diode characteristics are restored, resulting in a sharp change in the forward voltage under different currents, ultimately leading to uneven brightness of the chip. SUMMARY

[0005] The technical problem to be solved by the present application is to provide an epitaxial wafer of Mini LED with low thyristor effect and a growth method thereof, which can improve the brightness consistency of Mini LED.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is as follows: an epitaxial wafer of Mini LED with low thyristor effect, comprising a buffer layer, a U-shaped GaN layer, an N-type GaN layer, a multi-quantum well active region layer and a P-type GaN layer grown on a substrate in sequence, wherein the multi-quantum well active region layer comprises a defect inducing layer, a Si-doped AlGaN layer and a multi-quantum well light emitting layer grown on the N-type GaN layer in sequence.

[0007] Another technical solution adopted by the present application is that the growth method of the epitaxial wafer of the Mini LED with low effect of the gas discharge tube, the growth of the defect inducing layer is performed in a reaction cavity, the temperature of the reaction cavity is set to 700-950 DEG C, 30000-60000 sccm of NH3 and 20-100 sccm of SiH4 are introduced at the same time, and the introduction time of NH3 and SiH4 is equal.

[0008] The present application has the beneficial effects that the epitaxial wafer of the Mini LED with low effect of the gas discharge tube provided by the present application sets a defect inducing layer after the N-type GaN layer to induce the generation of defects, controls the position and size of the V-type defect generation, makes the size of the V-type defect of the multi-quantum well layer basically consistent, avoids the effect of the gas discharge tube formed due to the uneven thickness, can significantly reduce the effect of the gas discharge tube of the epitaxial layer, and improves the brightness consistency of the Mini LED; meanwhile, the Si-doped AlGaN layer is set after the defect inducing layer to replace the traditional expansion layer, which can not only have the current expansion effect, but also avoid the weak P-type conductivity due to the high carbon content, and form three PN contact surfaces with the multi-quantum well light-emitting layer and the P-type GaN layer behind to generate strong effect of the gas discharge tube. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 The VFD test diagram of the present application embodiments 1-3. DETAILED DESCRIPTION

[0010] In order to explain the technical content, the achieved purposes and effects of the present application in detail, the following will be explained in combination with the embodiments and the accompanying drawings.

[0011] An epitaxial wafer of the Mini LED with low effect of the gas discharge tube, comprising a buffer layer, a U-type GaN layer, an N-type GaN layer, a multi-quantum well active region layer and a P-type GaN layer grown on a substrate in sequence, the multi-quantum well active region layer comprises a defect inducing layer, a Si-doped AlGaN layer and a multi-quantum well light-emitting layer grown on the N-type GaN layer in sequence.

[0012] From the above description, the beneficial effects of the present application are that: due to the existence of large lattice mismatch and thermal mismatch between the gallium nitride material and the substrate, there is a large stress in the epitaxial growth, and then V-type defects are generated, and the phenomenon of inconsistent thickness occurs in the pile crystal process, which is particularly prone to occur in the multi-quantum well light-emitting layer; the uneven thickness is easy to cause the PN layer to interleave with each other to form a thyristor effect. The present application sets a defect inducing layer after the N-type GaN layer, induces the generation of defects, controls the position and size of the V-type defect generation, makes the size of the V-type defect of the multi-quantum well layer basically consistent, avoids the thyristor effect formed by the uneven thickness; at the same time, the Si-doped AlGaN layer is set after the defect inducing layer to replace the traditional expansion layer, which can not only play the current expansion effect, but also avoid the weak P-type conductivity caused by high carbon content, and form three PN contact surfaces with the multi-quantum well light-emitting layer and the P-type GaN layer behind, to produce a strong thyristor effect.

[0013] The position of the defect inducing layer and the Si-doped AlGaN layer of the present application cannot be adjusted. The defect inducing layer is located between the N-type GaN layer and the multi-quantum well light-emitting layer, and is used to induce the generation of defects, so that the size of the V-type defect extending from the defect inducing layer to the multi-quantum well light-emitting layer is basically consistent; the Si-doped AlGaN layer is used to expand the current laterally, so that the electrons entering the multi-quantum well light-emitting layer from the N-type GaN layer are slowed down and not congested.

[0014] Further, the P-type GaN layer includes a low-temperature P-GaN layer, an electron blocking layer and a high-temperature P-GaN layer which are sequentially grown on the multi-quantum well active region layer.

[0015] Further, the doping source of the defect inducing layer is at least one of Si, In, Al or Mg.

[0016] Further, the doping source of the defect inducing layer is Si.

[0017] Another technical solution adopted by the present application is that: the growth method of the low-thyristor effect Mini LED epitaxial wafer described above, the growth of the defect inducing layer is carried out in a reaction chamber, the temperature of the reaction chamber is set to 700-950 DEG C, 30000-60000 sccm of NH3 and 20-100 sccm of SiH4 are introduced at the same time, and the introduction time of NH3 and SiH4 is equal.

[0018] Further, the growth of the defect-inducing layer is performed in a reaction cavity, the temperature of the reaction cavity is set to 700-950 DEG C, 30000-60000 sccm of NH3, 20-40 sccm of SiH4, 30-50 sccm of TMGa source and 600-1300 sccm of TMIn source are introduced, and the introduction time of NH3, SiH4, TMGa source and TMIn source is equal, and the doping concentration of In is 1E+20-2E+20 atom / cm 3 , and the doping concentration of Si is 1.5E+18-2.5E+18 atom / cm 3 .

[0019] From the above description, the present application provides a simple and efficient defect-inducing layer, which can induce the generation of defects, control the size and position of V-type defects, make the size of V defects of the well barrier layer of the multi-quantum well light-emitting layer basically uniform, effectively improve the PN layer interlacing caused by uneven thickness in the barrier crystallization process, thereby reducing the thyristor effect and improving the consistency of chip brightness under different currents.

[0020] The doping source of the defect-inducing layer is at least one of Si, In, Al or Mg, when the doping source is Si and In, the large atomic radius and activity of In atom can be utilized, and the doping efficiency is higher and the generation of defects is easier to induce.

[0021] Further, the thickness of the defect-inducing layer is 2-30 nm.

[0022] From the above description, by controlling the thickness of the defect-inducing layer and the concentration of the doping source, defects are induced to generate at a specific position, and the thyristor effect is avoided.

[0023] Further, the growth of the Si-doped AlGaN layer is performed in a reaction cavity, the temperature of the reaction cavity is set to 700-950 DEG C, 30000-60000 sccm of NH3, 30-50 sccm of TMGa (trimethyl gallium) source and 150-200 sccm of TMAl (trimethyl aluminum) source are introduced, and the introduction time of NH3, TMGa source and TMAl source is equal.

[0024] From the above description, the present application replaces the traditional low-doped or undoped current spreading layer with the Si-doped AlGaN layer. The traditional current spreading layer has weak P-type conductivity due to low Si doping and high carbon content, forms three PN contact surfaces with the subsequent multi-quantum well light-emitting layer and P layer GaN layer, and generates strong thyristor effect. The Si-doped AlGaN layer of the present application can effectively improve the current spreading and reduce the carbon content, thereby reducing the thyristor effect to the greatest extent and improving the consistency of chip brightness under different currents.

[0025] Further, the mole number of Al in the Si-doped AlGaN layer linearly decreases in the direction away from the substrate.

[0026] As described above, the Al component in the Si-doped AlGaN layer decreases, the energy band is adjusted, the height of the conduction band barrier is increased, the electron moving speed is reduced, the current spreading is increased, and the light emitting efficiency is improved; both the current spreading effect and the voltage increase are not obvious.

[0027] Further, the thickness of the Si-doped AlGaN layer is 10-30 nm.

[0028] Preferably, the thickness of the Si-doped AlGaN layer is 20 nm.

[0029] As described above, if the thickness of the Si-doped AlGaN layer is too thick, the impedance will be increased, resulting in a significant increase in voltage; if the thickness is too thin, the current spreading effect is not obvious, affecting the light emitting efficiency.

[0030] Further, when growing the last barrier layer of the multi-quantum well light emitting layer, the ratio of the mole number of Al to the mole number of GaN in the last barrier layer linearly decreases from 15% to 0% in the direction away from the substrate.

[0031] As described above, the mole number of Al in the last barrier layer of the multi-quantum well light emitting layer linearly decreases in the direction away from the substrate, which can maximize the ESD performance and light emitting efficiency of the LED; specifically, the mole number of Al linearly decreases, the energy band is adjusted, the height of the valence band barrier of the hole injection is reduced, the height of the conduction band barrier of the electron leakage is increased, the carrier leakage is suppressed, the injection efficiency of the carrier is improved, and the light emitting efficiency is improved.

[0032] Further, before growing the buffer layer, hydrogen is used to purge the reaction chamber, so that the reaction chamber is filled with hydrogen; then the hydrogen purging is closed, the pressure of the reaction chamber is set to 500-600 mbar, the temperature is set to 1000-1200℃, and the process is continued for 7-10 min; then hydrogen and ammonia are used to purge the reaction chamber.

[0033] As described above, before growing the buffer layer, the reaction chamber is purged of impurities, and the gas required for the subsequent reaction is introduced in advance; the substrate is pretreated by increasing the temperature and pressure of the reaction chamber, so that the quality of the structure grown on the substrate in the subsequent process is improved.

[0034] Further, the low-temperature P-GaN layer is grown in the reaction cavity, the temperature of the reaction cavity is set to 700-950 DEG C, the pressure is 300-800 mbar, 55000-65000 sccm of NH3, 25-50 sccm of TMGa and 400-950 sccm of Cp2Mg are simultaneously introduced into the reaction cavity, the introduction time of NH3, TMGa and Cp2Mg is the same, the low-temperature P-GaN layer with a thickness of 20-80 nm is grown on the multi-quantum well light-emitting layer, and the Mg doping concentration of the low-temperature P-GaN is 1.1E+16-5E+16 atom / cm 3 .

[0035] As can be known from the above description, the low-temperature P-GaN layer can not only provide holes, but also protect the multi-quantum well active region from being damaged by high temperature, and the performance and light-emitting efficiency of the LED can be maximally improved.

[0036] Embodiment 1 of the present application is a preparation method of an epitaxial structure of a Mini LED with low thyristor effect, comprising the following steps:

[0037] S1: the substrate is placed into the reaction cavity of a metal organic chemical vapor deposition device, and the reaction cavity is purged by using hydrogen; then the purging of hydrogen is closed, the pressure of the reaction cavity is set to 550 mbar, and the temperature is set to 1100 DEG C, and the process is continued for 8.5 min; then the reaction cavity is purged by using hydrogen and ammonia;

[0038] S2: the pressure of the reaction cavity is set to 150 mbar, the temperature is set to 850 DEG C, 70 sccm of TMGa and 35 sccm of TMAl source are simultaneously introduced into the reaction cavity, and the process is continued for 5 min, so that the buffer layer with a thickness of 0.015 um is grown on the substrate.

[0039] S3: the pressure of the reaction cavity is set to 325 mbar, the temperature is set to 1000 DEG C, 350 sccm of TMGa source is simultaneously introduced into the reaction cavity, and the process is continued for 18 min, so that the U-shaped GaN layer is formed on the buffer layer.

[0040] S4: the pressure of the reaction cavity is set to 750 mbar, and the N-type GaN layer with a thickness of 2.5 um is grown on the U-shaped GaN layer.

[0041] S5: a defect induction layer is grown on the N-type GaN layer, the temperature of the reaction cavity is set to 800 DEG C, 50000 sccm of NH3 and 60 sccm of SiH4 are introduced, and a 15 nm SiN defect induction layer is grown on the N-type GaN layer.

[0042] S6: set the temperature of the reaction cavity to 800℃, introduce 40000sccm of NH3, 40sccm of TMGa source and 170sccm of TMAl source, the doping source is Si doping, and the doping concentration is 1.5E+17atom / cm 3 , and grow a 20nm Si-doped AlGaN layer on the defect-inducing layer.

[0043] S7: alternately grow the well layer and the barrier layer of the multi-quantum well light-emitting layer on the Si-doped AlGaN layer, the thickness of the multi-quantum well active region layer is 0.18μm; the well layer is InGaN, and the barrier layer is GaN; one cycle is formed by growing one well layer and one barrier layer, and the number of InGaN / GaN cycles is 13.

[0044] When growing the well layer, set the temperature of the reaction cavity to 750℃, and introduce 1300sccm of TMIn and 210sccm of TEGa source into the reaction cavity; the doping concentration of In in each well layer is 1.5E+20atom / cm 3 ;

[0045] When growing the barrier layer, set the temperature of the reaction cavity to 900℃, and introduce 600sccm of TEGa source into the reaction cavity.

[0046] When growing the last barrier layer, introduce the TMAl source into the reaction cavity, and linearly decrease the flow rate of the TMAl source from 180sccm to 0sccm, so that the number of moles of Al in the last barrier layer linearly decreases along the direction away from the substrate, and the ratio of the number of moles of Al to the number of moles of GaN linearly decreases from 15% to 0%.

[0047] S8: set the temperature of the reaction cavity to 850℃, the pressure to 550mbar, introduce 60000sccm of NH3, 35sccm of TMGa and 600sccm of Cp2Mg into the reaction cavity, and grow a 60nm low-temperature P-GaN layer on the multi-quantum well light-emitting layer, the Mg doping concentration is 3E+16atom / cm 3 .

[0048] S9: set the temperature of the reaction cavity to 850℃, introduce 40000sccm of NH3, 40sccm of TMGa source, 1800sccm of Cp2Mg and 170sccm of TMAl source, and grow an electron blocking layer with a thickness of 60nm on the low-temperature P-GaN layer.

[0049] In the P-type electron blocking layer, the doping concentration of Mg is 1E+17atom / cm 3 , and the doping concentration of Al is 1E+17atom / cm 3 .

[0050] S10: set the temperature of the reaction cavity to 955 DEG C, the pressure to 800 mbar, introduce 67500 sccm of NH3, 37.5 sccm of TMGa and 2500 sccm of Cp2Mg into the reaction cavity, and form a 75 nm high-temperature P-type GaN layer on the P-type electron blocking layer; and the preparation of the Mini LED epitaxial structure is completed.

[0051] Embodiment 2 of the present application is:

[0052] Embodiment 2 differs from Embodiment 1 only in that S6: the temperature of the reaction cavity is set to 800 DEG C, 40000 sccm of NH3, 40 sccm of TMGa source and 170 sccm of TMAl source are introduced, the doping source is Si doping, and the doping concentration is 1.5E+17 atom / cm 3 , a 20 nm Si-doped AlGaN layer is grown on the defect-inducing layer; wherein the number of moles of Al decreases linearly in the direction away from the substrate, and the doping concentration of Al decreases from 2E+19 to 1E+19 atom / cm 3 .

[0053] Embodiment 3 of the present application is:

[0054] Embodiment 3 differs from Embodiment 1 only in that:

[0055] S5: a defect-inducing layer is grown on the N-type GaN layer, the temperature of the reaction cavity is set to 800 DEG C, 40000 sccm of NH3, 30 sccm of SiH4, 40 sccm of TMGa source and 1300 sccm of TMIn source are introduced, and a 15 nm Si-doped InGaN defect-inducing layer is grown on the N-type GaN layer, the Si doping concentration is 2.5E+18 atom / cm 3 , and the doping concentration of In is 1.5E+20 atom / cm 3 .

[0056] S6: the temperature of the reaction cavity is set to 800 DEG C, 40000 sccm of NH3, 40 sccm of TMGa source and 170 sccm of TMAl source are introduced, the doping source is Si doping, and the doping concentration is 1.5E+17 atom / cm 3 , a 20 nm Si-doped AlGaN layer is grown on the defect-inducing layer; wherein the number of moles of Al decreases linearly in the direction away from the substrate, and the doping concentration of Al decreases from 2E+19 to 1E+19 atom / cm 3 .

[0057] The comparative example of the present application is:

[0058] The difference between the comparative example and example 1 is only that: no defect inducing layer is arranged on the N-type GaN layer, and a non-doped current spreading layer with a thickness of 40 nm is directly grown; when the non-doped current spreading layer is grown, the reaction cavity temperature is set to 800 DEG C, 40000 sccm of NH3 and 40 sccm of TMGa source are introduced.

[0059] The epitaxial wafer grown in the comparative example, example 1, example 2 and example 3 is prepared into a chip, and VFD test (VFD is a peak voltage of LED transient, which is characterized by the difference of forward voltage drop difference under a small current IF = 10uA, that is, the difference value of peak voltage and steady voltage, and the smaller the value is, the lower the thyristor effect of the LED device is) is carried out, and the test result is shown in Table 1. Figure 1 Figure 1 It can be known from Table 1 that the VFD values of the examples of the present application are all lower than those of the comparative example, and the growth method of the present application can effectively reduce the thyristor effect; the VFD values of example 2 and example 3 are obviously reduced compared with example 1, which shows that the thyristor effect is lower when the doping source of the defect inducing layer is Si / In than when the doping source is Si, and the linear decrease of the molar number of Si doped Al in the AlGaN layer in the direction away from the substrate can further reduce the thyristor effect.

[0060] Example 4 of the present application is a preparation method of an epitaxial structure of a Mini LED with low thyristor effect, which comprises the following steps:

[0061] S1: the substrate is placed into a reaction cavity of a metal organic chemical vapor deposition device, and the reaction cavity is purged by using hydrogen; then the purging of hydrogen is closed, the pressure of the reaction cavity is set to 500 mbar, and the temperature is set to 1000 DEG C, and the process is continued for 7 min; then the reaction cavity is purged by using hydrogen and ammonia;

[0062] S2: the pressure of the reaction cavity is set to 100 mbar, the temperature is set to 800 DEG C, 60 sccm of TMGa and 25 sccm of TMAl source are introduced into the reaction cavity at the same time, and the process is continued for 4 min, so that a buffer layer with a thickness of 0.01 um is grown on the substrate.

[0063] S3: the pressure of the reaction cavity is set to 150 mbar, the temperature is set to 900 DEG C, 300 sccm of TMGa source is introduced into the reaction cavity at the same time, and the process is continued for 6 min, so that a U-shaped GaN layer is formed on the buffer layer.

[0064] S4: the pressure of the reaction cavity is set to 500 mbar, and an N-type GaN layer with a thickness of 2 um is grown on the U-shaped GaN layer.

[0065] ​S5: A defect inducing layer is grown on the N-type GaN layer, the reaction cavity temperature is set to 700 °C, 30000 sccm of NH3 and 20 sccm of SiH4 are introduced, and a 2 nm SiN defect inducing layer is grown on the N-type GaN layer.

[0066] S6: The reaction cavity temperature is set to 700 °C, 30000 sccm of NH3, 30 sccm of TMGa source and 150 sccm of TMAl source are introduced, the doping source is Si doping, and the doping concentration is 2E+16 atom / cm 3 A 20 nm Si-doped AlGaN layer is grown on the defect inducing layer.

[0067] S7: A well layer and a barrier layer of a multi-quantum well light emitting layer are alternately grown on the Si-doped AlGaN layer, the thickness of the multi-quantum well active region layer is 0.15 μm; the well layer is InGaN, and the barrier layer is GaN; one cycle is formed by growing one well layer and one barrier layer, and the number of InGaN / GaN cycles is 10;

[0068] When the well layer is grown, the reaction cavity temperature is set to 700 °C, 1200 sccm of TMIn and 25 sccm of TEGa source are introduced into the reaction cavity; the In doping concentration of each well layer is 1E+20 atom / cm 3 ;

[0069] When the barrier layer is grown, the reaction cavity temperature is set to 800 °C, 300 sccm of TEGa source is introduced into the reaction cavity;

[0070] When the last barrier layer is grown, the TMAl source is introduced into the reaction cavity, the flow rate of the TMAl source is linearly decreased from 180 sccm to 0 sccm, the mole number of Al in the last barrier layer is linearly decreased along the direction away from the substrate, and the ratio of the mole number of Al to the mole number of GaN is linearly decreased from 15% to 0%.

[0071] S8: The reaction cavity temperature is set to 700 °C, the pressure is 300 mbar, 550000 sccm of NH3, 25 sccm of TMGa and 400 sccm of Cp2Mg are introduced into the reaction cavity, a 60 nm low-temperature P-GaN layer is grown on the multi-quantum well light emitting layer, and the Mg doping concentration is 3E+16 atom / cm 3 .

[0072] S9: The reaction cavity temperature is set to 700 °C, 30000 sccm of NH3, 30 sccm of TMGa source, 1500 sccm of Cp2Mg and 150 sccm of TMAl source are introduced, and a 50 nm thick electron blocking layer is grown on the low-temperature P-GaN layer;

[0073] The doping concentration of Al in the P-type electron blocking layer is 1E+18 atom / cm 3 .

[0074] S10: set the reaction cavity temperature to 900 DEG C, the pressure to 600 mbar, introduce 60000 sccm of NH3, 25 sccm of TMGa and 2000 sccm of Cp2Mg into the reaction cavity, and form a 60 nm high-temperature P-type GaN layer on the P-type electron blocking layer; the preparation of the Mini LED epitaxial structure is completed.

[0075] Embodiment 5 of the application is a preparation method of a Mini LED epitaxial structure with low gate current effect, comprising the following steps:

[0076] S1: place the substrate into the reaction cavity of a metal organic chemical vapor deposition device, and use hydrogen to purge the reaction cavity; then close the hydrogen purge, set the reaction cavity pressure to 600 mbar and the temperature to 1200 DEG C, and maintain for 10 min; and then use hydrogen and ammonia to purge the reaction cavity.

[0077] S2: set the reaction cavity pressure to 200 mbar and the temperature to 900 DEG C, and simultaneously introduce 80 sccm of TMGa and 45 sccm of TMAl source into the reaction cavity, and maintain for 6 min, so that a buffer layer with a thickness of 0.02 μm is grown on the substrate.

[0078] S3: set the reaction cavity pressure to 500 mbar and the temperature to 1100 DEG C, and simultaneously introduce 400 sccm of TMGa source into the reaction cavity, and maintain for 30 min, to form a U-shaped GaN layer on the buffer layer.

[0079] S4: set the reaction cavity pressure to 1000 mbar, and grow a N-type GaN layer with a thickness of 3 μm on the U-shaped GaN layer.

[0080] S5: grow a defect induction layer on the N-type GaN layer, set the reaction cavity temperature to 950 DEG C, introduce 60000 sccm of NH3 and 100 sccm of SiH4, and grow a 30 nm SiN defect induction layer on the N-type GaN layer.

[0081] S6: set the reaction cavity temperature to 950 DEG C, introduce 60000 sccm of NH3, 50 sccm of TMGa source and 200 sccm of TMAl source, the doping source is Si doping, and the doping concentration is 1E+20 atom / cm 3 , and grow a 30 nm Si-doped AlGaN layer on the defect induction layer.

[0082] S7: alternately growing a well layer and a barrier layer of a multi-quantum well light-emitting layer on the Si-doped AlGaN layer, the thickness of the multi-quantum well active region layer being 0.2 μm; the well layer being InGaN, and the barrier layer being GaN, one cycle being formed by growing one well layer and one barrier layer, the number of InGaN / GaN cycles being 16;

[0083] When the well layer is grown, the reaction cavity temperature is set to 800 DEG C, 1500 sccm of TMIn and 400 sccm of TEGa source are introduced into the reaction cavity; the In doping concentration of each well layer is 2E+20 atom / cm 3 ;

[0084] When the barrier layer is grown, the reaction cavity temperature is set to 950 DEG C, 1000 sccm of TEGa source is introduced into the reaction cavity;

[0085] When the last barrier layer is grown, TMAl source is introduced into the reaction cavity, the flow rate of the TMAl source is linearly decreased from 180 sccm to 0 sccm, so that the number of moles of Al in the last barrier layer is linearly decreased along the direction away from the substrate, and the ratio of the number of moles of Al to the number of moles of GaN is linearly decreased from 15% to 0%.

[0086] S8: the reaction cavity temperature is set to 950 DEG C, the pressure is 800 mbar, 65000 sccm of NH3, 50 sccm of TMGa and 950 sccm of Cp2Mg are introduced into the reaction cavity, and an 80 nm low-temperature P-GaN layer is grown on the multi-quantum well light-emitting layer, the Mg doping concentration being 5E+16 atom / cm 3 .

[0087] S9: the reaction cavity temperature is set to 950 DEG C, 60000 sccm of NH3, 50 sccm of TMGa source, 2000 sccm of Cp2Mg and 200 sccm of TMAl source are introduced, and a 70 nm thick electron blocking layer is grown on the low-temperature P-GaN layer;

[0088] In the P-type electron blocking layer, the doping concentration of Mg is 1E+19 atom / cm 3 , and the doping concentration of Al is 1E+17 atom / cm 3 .

[0089] S10: the reaction cavity temperature is set to 1050 DEG C, the pressure is 1000 mbar, 75000 sccm of NH3, 50 sccm of TMGa and 3000 sccm of Cp2Mg are introduced into the reaction cavity, and a 90 nm high-temperature P-type GaN layer is formed on the P-type electron blocking layer; the preparation of the Mini LED epitaxial structure is completed.

[0090] Embodiment 6 of the application is:

[0091] Example 6 differs from Example 3 only in that the doping concentration of In in S5 is 1E+20 atom / cm 3 , the Si doping concentration is 2E+18 atom / cm 3 .

[0092] Example 7 of the present application is:

[0093] Example 7 differs from Example 3 only in that the doping concentration of In in S5 is 2E+20 atom / cm 3 , the Si doping concentration is 1.5E+18 atom / cm 3 .

[0094] In summary, the present application provides a Mini LED epitaxial wafer with low gate current effect, which sequentially grows a buffer layer, a U-shaped GaN layer, an N-type GaN layer, a defect induction layer of the N-type GaN layer, a Si-doped AlGaN layer, a multi-quantum well light-emitting layer, a low-temperature P-GaN layer, an electron blocking layer and a high-temperature P-GaN layer on a substrate. Among them, by setting the Si-doped AlGaN layer and the defect induction layer, the gate current effect of the epitaxial layer can be significantly reduced, and the brightness consistency of the Mini LED can be improved; by doping the number of moles of Al in the last barrier layer of the multi-quantum well light-emitting layer to decrease linearly in the direction away from the substrate, and by setting the low-temperature P-GaN layer, the ESD performance and light-emitting efficiency of the LED can be maximized, and the gate current effect can be further reduced.

[0095] The above description is only an example of the present application, and does not limit the patent scope of the present application. Any equivalent transformation or direct or indirect application in the related technical field based on the content of the present application specification and drawings is also included in the patent protection scope of the present application.

Claims

1. An epitaxial wafer of a Mini LED with low gate current effect, comprising a buffer layer, a U-shaped GaN layer, an N-type GaN layer, a multi-quantum well active region layer and a P-type GaN layer grown in sequence on a substrate, characterized in that, The multi-quantum well active region layer comprises a defect inducing layer, a Si-doped AlGaN layer and a multi-quantum well light emitting layer grown in sequence on the N-type GaN layer; The P-type GaN layer comprises a low-temperature P-GaN layer, an electron blocking layer and a high-temperature P-GaN layer grown in sequence on the multi-quantum well active region layer; The defect inducing layer is doped with at least one of Si, In, Al or Mg.

2. The low-gate effect Mini LED epitaxial wafer of claim 1, wherein, The defect inducing layer is doped with Si.

3. The growth method of an epitaxial wafer of a low-gate effect Mini LED according to claim 1, characterized in that, The defect inducing layer is grown in a reaction chamber, wherein the temperature of the reaction chamber is set to 700-950℃, 30000-60000sccm of NH3 and 20-100sccm of SiH4 are introduced into the reaction chamber, and the introduction time of NH3 and SiH4 is equal.

4. The growth method of the low-gate current effect Mini LED epitaxial wafer according to claim 3, wherein the growth of the defect inducing layer is performed in a reaction cavity, the temperature of the reaction cavity is set to 700-950 ℃, 30000-60000 sccm of NH3, 20-40 sccm of SiH4, 30-50 sccm of TMGa source and 600-1300 sccm of TMIn source are introduced at the same time, the introduction time of NH3, SiH4, TMGa source and TMIn source is equal, the doping concentration of In is 1E+20-2E+20 atom / cm 3 , and the Si doping concentration is 1.5E+18-2.5E+18 atom / cm 3 .

5. The growth method of an epitaxial wafer of a low-gate-liquid effect Mini LED according to claim 3, characterized in that, The defect inducing layer has a thickness of 2-30nm.

6. The growth method of an epitaxial wafer of a low-gate-liquid effect Mini LED according to claim 3, characterized in that, The Si-doped AlGaN layer is grown in a reaction chamber, wherein the temperature of the reaction chamber is set to 700-950℃, 30000-60000sccm of NH3, 30-50sccm of TMGa source and 150-200sccm of TMAl source are introduced into the reaction chamber, and the introduction time of NH3, TMGa source and TMAl source is equal.

7. The growth method of an epitaxial wafer of low-gate-fluid-effect Mini LED according to claim 6, characterized in that, The mole number of Al in the Si-doped AlGaN layer decreases linearly in the direction away from the substrate.

8. The growth method of an epitaxial wafer of a low-gate-liquid effect Mini LED according to claim 3, characterized in that, When the last barrier layer of the multi-quantum well light emitting layer is grown, the ratio of the mole number of Al to the mole number of GaN in the last barrier layer decreases linearly from 15% to 0% in the direction away from the substrate.

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