Light emitting device

Abstract

The embodiment of the invention discloses a light-emitting device, for example, comprising a first epitaxial structure which comprises an N-type GaN layer, a light-emitting layer and a P-type GaN layer which are arranged in sequence; the second epitaxial structure comprises an electron channel layer and a barrier layer which are arranged in sequence; and a connection layer; wherein the connection layer is connected between the first epitaxial structure and the second epitaxial structure, and the material of the connection layer comprises GaN. According to the embodiment of the invention, the GaN connecting layer is arranged to integrate the two epitaxial structures on one light-emitting device, so that the light-emitting device provided by the embodiment of the invention not only realizes light emitting, but also realizes constant-current light emitting, and the problem that the head and the tail of an existing LED lamp head are uneven in light emitting brightness can be more flexibly solved; and the two epitaxial structures are integrated on one light-emitting device, so that the light-emitting device provided by the embodiment of the invention can be more flexibly applied to a light-emitting device needing constant current.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a light-emitting device. Background Art

[0002] With the development of semiconductor technology, LED (Light-emitting Diode) technology is becoming more and more mature, but there is still room for improvement in many design details. For example, for the LED light strip products with multiple LED strings connected in parallel on the market, when they are used in parallel over a long distance, the different LED strings at the head and tail ends have a large difference in distance from the power supply, resulting in a large difference in voltage drop, which will cause uneven brightness of the entire light strip. Summary of the invention

[0003] In view of at least some of the problems and shortcomings in the prior art, the embodiments of the present invention disclose a light-emitting device and a method for preparing the light-emitting device, so as to more flexibly solve the problem of uneven light brightness at the head and tail of the existing LED light strip.

[0004] On the one hand, the light-emitting device provided by an embodiment of the present invention, for example, includes: a first epitaxial structure, including an N-type GaN layer, a light-emitting layer and a P-type GaN layer arranged in sequence; a second epitaxial structure, including an electron channel layer and a barrier layer arranged in sequence; and a connecting layer; wherein the connecting layer is connected between the first epitaxial structure and the second epitaxial structure, and the material of the connecting layer includes GaN.

[0005] The embodiment of the present invention integrates two epitaxial structures into one light-emitting device by setting a GaN connecting layer, so that the light-emitting device provided by the embodiment of the present invention can not only realize light emission but also realize constant current light emission, thereby solving the problem of uneven light emission at the head and tail of the existing LED light strip. In addition, based on the integration of the two epitaxial structures into one light-emitting device, the light-emitting device provided by the embodiment of the present invention can be more flexibly applied to light-emitting devices requiring constant current.

[0006] On the other hand, a light-emitting device provided in an embodiment of the present invention includes: a substrate, a connecting layer, a first epitaxial structure and a second epitaxial structure; one of the first epitaxial structure and the second epitaxial structure is arranged between the substrate and the connecting layer, and the other of the first epitaxial structure and the second epitaxial structure is arranged on a side of the connecting layer away from the substrate; wherein the roughness of the side of the connecting layer away from the substrate is smaller than the roughness of the side of the first epitaxial structure or the second epitaxial structure arranged on the substrate away from the substrate.

[0007] It can be seen from the above that the above technical features of the present invention can have one or more of the following beneficial effects: the embodiment of the present invention integrates two epitaxial structures into one light-emitting device by setting a GaN connecting layer, so that the light-emitting device provided by the embodiment of the present invention not only realizes light emission but also realizes constant current light emission, which can more flexibly solve the problem of uneven brightness of the head and tail of the existing LED light strip, and based on the integration of two epitaxial structures into one light-emitting device, the light-emitting device provided by the embodiment of the present invention can be more flexibly applied to light-emitting devices that require constant current. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0009] Figure 1 A schematic structural diagram of a light emitting device provided in an embodiment of the present invention.

[0010] Figure 2 A schematic structural diagram of a light emitting device provided in the first embodiment of the present invention.

[0011] Figure 3 for Figure 2 Schematic diagram of the specific structure of the light-emitting device.

[0012] Figure 4 A schematic structural diagram of a light emitting device provided in a second embodiment of the present invention.

[0013] Figure 5 for Figure 4 Schematic diagram of the specific structure of the light-emitting device.

[0014] Figure 6 The present invention is a flowchart of a method for preparing a light-emitting device according to a first embodiment of the present invention.

[0015] Figure 7 A flow chart of a method for preparing a light-emitting device provided in accordance with a second embodiment of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0017] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0018] The directional terms mentioned in the embodiments of the present invention, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and understand the present invention, but not to limit the present invention. For the sake of understanding and ease of description, the size and thickness of each component shown in the drawings are arbitrarily shown, but the present invention is not limited to this. When a component such as a layer, film, region or substrate is referred to as "on (another component)", the component may be directly on the other component, or there may be an intermediate component. In addition, in the specification, "arranging (several components) in sequence" means that these components have a relative arrangement order, but does not mean that these components must be connected to each other, and there may be other intermediate components between these components.

[0019] In addition, the division of multiple embodiments in the present invention is only for the convenience of description and should not constitute a special limitation. The features in various embodiments can be combined and referenced to each other without contradiction.

[0020] See also Figure 1 , the embodiment of the present invention, for example, provides a light-emitting device 10, for example, including: a second epitaxial structure 500, a first epitaxial structure 300 and a connecting layer 400; wherein the connecting layer 400, for example, is connected between the second epitaxial structure 500 and the first epitaxial structure 300, and the material of the connecting layer 400 includes GaN. The first epitaxial structure 300, for example, includes an N-type GaN layer 310, a light-emitting layer 330 and a P-type GaN layer 350 arranged in sequence, and the first epitaxial structure is, for example, a light-emitting diode epitaxial structure, which can, for example, realize LED light emission; the second epitaxial structure 500, for example, includes an electron channel layer 510 and a barrier layer 530 arranged in sequence, which can, for example, realize constant current.

[0021] The embodiment of the present invention integrates two epitaxial structures into one light-emitting device by setting a GaN connecting layer, so that the light-emitting device provided by the embodiment of the present invention can not only realize light emission but also realize constant current light emission, thereby more flexibly solving the problem of uneven light brightness at the head and tail of the existing LED light strip. In addition, based on the integration of the two epitaxial structures into one light-emitting device, the light-emitting device provided by the embodiment of the present invention can be more flexibly applied to light-emitting devices requiring constant current.

[0022] The light emitting device 10 is described below with reference to a specific embodiment.

[0023] [First embodiment]

[0024] See also Figure 2 The light emitting device 10 provided in the first embodiment of the present invention, for example, comprises: a substrate 100, a buffer layer 200, a first epitaxial structure 300, a connecting layer 400 and a second epitaxial structure 500. The buffer layer 200 is, for example, disposed on one side of the substrate 100, the first epitaxial structure 300 is, for example, disposed on a side of the buffer layer 200 away from the substrate 100, the connecting layer 400 is, for example, disposed on a side of the first epitaxial structure 300 away from the buffer layer 200, and the second epitaxial structure 500 is, for example, disposed on a side of the connecting layer 400 away from the first epitaxial structure 300. The material of the connecting layer 400 comprises GaN.

[0025] Specifically, the material of the substrate 100 is, for example, Al2O3, for example, a sapphire substrate. AlN is deposited on the sapphire substrate, for example, by a plasma enhanced chemical vapor deposition method, for example, the thickness of the deposited AlN is 10 to 100 nanometers, and the substrate is heat-treated in a hydrogen environment at 1000 to 1200° C. for 8 to 12 minutes to obtain the substrate 100.

[0026] Further, see Figure 3, the buffer layer 200, for example, includes a first buffer layer 210 and a second buffer layer 220 arranged in sequence, and the first buffer layer 210, for example, is arranged on the substrate 100. For example, the material of the first buffer layer 210 is, for example, AlN and / or GaN, that is, the first buffer layer 210 is, for example, an AlN buffer layer, or the first buffer layer 210 is, for example, a GaN buffer layer, or the first buffer layer 210, for example, includes both an AlN buffer layer and a GaN buffer layer, and the GaN buffer layer is, for example, arranged on the side of the AlN buffer layer away from the substrate 100. Wherein, the thickness of the AlN buffer layer is, for example, 1 to 100 nanometers. The provision of the AlN buffer layer helps to obtain a GaN material with higher crystal quality and higher resistance. Specifically, compared with the substrate 100 (sapphire substrate), the lattice mismatch and thermal expansion coefficient mismatch between AlN and GaN are smaller, and GaN is epitaxially grown on the AlN surface, and the obtained GaN material has a lower XRD (102) / XRD (002), a smoother surface, and a higher resistance. Among them, XRD (102) is the characteristic peak of the crystal plane of GaN material 102 on the XRD diffraction spectrum, and XRD (002) is the characteristic peak of the crystal plane of GaN material 002 on the XRD diffraction spectrum. Furthermore, by setting a GaN buffer layer in a low temperature environment (for example, 500°C to 1000°C), stress release is helpful, thereby effectively avoiding cracks in the appearance of the light-emitting device. The first buffer layer 210 is used, for example, to buffer the problem of mismatch between the Al2O3 lattices in GaN and the substrate 100. The material of the second buffer layer 220 is, for example, undoped GaN, the thickness of the second buffer layer 220 is, for example, 2 to 4 microns, and the second buffer layer 220 is, for example, a high-resistance layer structure. For example, the resistance of the second buffer layer 220 is 1.17e11Ω / □. The second buffer layer 220 is used, for example, to obtain a GaN material with better crystal quality.

[0027] In accordance with the above, see Figure 3 The first epitaxial structure 300, for example, includes an N-type GaN layer 310, a stress adjustment layer 320, a light-emitting layer 330, an electron blocking layer 340 and a P-type GaN layer 350 arranged in sequence, wherein the N-type GaN layer 310 is, for example, arranged on a side of the second buffer layer 220 away from the first buffer layer 210.

[0028] Specifically, the material of the N-type GaN layer 310 includes, for example, Si-doped GaN, and the doping concentration of the N-type GaN layer 310 is in the range of 1e19 cm -3 ~3e19cm -3 The thickness of the N-type GaN layer 310 is, for example, 1 to 4 micrometers. The material of the stress adjustment layer 320 includes, for example, Si-doped GaN, and the doping concentration of the stress adjustment layer 320 is in the range of 1e17 cm -3 ~8e18cm -3. The light-emitting layer 330 is, for example, a superlattice multiple quantum well light-emitting layer. For example, the light-emitting layer 330 includes, for example, InGaN and GaN lattices. The provision of the stress adjustment layer 320 helps to obtain InGaN materials with better crystal quality. The material of the electron blocking layer 340 includes, for example, AlGaN, and the thickness of the electron blocking layer 340 is, for example, 10 to 30 nanometers. The material of the P-type GaN layer 350 includes, for example, Mg-doped GaN, and the doping concentration range of the P-type GaN layer 350 is 1e18cm -3 ~2e20cm -3 The thickness of the P-type GaN layer 350 is, for example, 30 to 500 nanometers.

[0029] As mentioned above, see Figure 3 The connection layer 400 is, for example, disposed on a side of the P-type GaN layer 350 away from the electron blocking layer 340, wherein the connection layer 400 is, for example, a flat high-resistance layer structure. For example, the roughness of the P-type GaN layer 350 is, for example, 0.3 to 0.5 nanometers, the roughness of the connection layer 400 is, for example, less than 0.3 nanometers, preferably, the roughness of the connection layer 400 is, for example, 0.22 nanometers, and the resistance Rs of the connection layer 400 is, for example, greater than 1e9Ω / □. The material of the connection layer 400 includes GaN, and the thickness of the connection layer 400 is, for example, greater than 100 nanometers, and preferably, the thickness of the connection layer 400 is, for example, 200 to 800 nanometers.

[0030] In a specific embodiment, the connection layer 400 is a GaN layer doped with Fe and / or C, and the doping concentration of the connection layer 400 is greater than 8e18cm -3 . The connection layer 400 is doped with Fe and / or C to increase the resistance of the connection layer 400. In another specific embodiment, the connection layer 400 is, for example, an undoped GaN layer, and a flat high-resistance connection layer 400 can be directly grown, for example, under external conditions. For example, the V / III ratio (NH3 / Ga ratio) of the connection layer 400 and the growth temperature of the connection layer 400 can be optimized. For example, the V / III ratio of the GaN connection layer is 900 to 2000, and the growth temperature is 1050°C to 1100°C, so as to obtain an undoped GaN connection layer 400 having a flat high-resistance characteristic.

[0031] Specifically, after the first epitaxial structure 300 is grown, its surface portion (i.e., the P-type GaN layer 350) is rough, and the roughness will affect the mobility of the second epitaxial structure 500. The embodiment of the present application provides a flat connection layer 400 to flatten the surface growth. Furthermore, the high-resistance connection layer 400 can prevent the second epitaxial structure from leaking electricity, thereby affecting the light-emitting condition of the light-emitting device. In addition, by providing the connection layer 400, it is also possible to prevent Mg in the P-type GaN layer 350 from diffusing into the second epitaxial structure 500.

[0032] Further, see Figure 3 The second epitaxial structure 500 , for example, includes an electron channel layer 510 , an isolation layer 520 , and a barrier layer 530 , which are arranged in sequence. The electron channel layer 510 , for example, is arranged on a side of the connection layer 240 away from the P-type GaN layer 350 .

[0033] The material of the electron channel layer 510 includes, for example, GaN or InGaN, and the thickness of the electron channel layer 510 is, for example, 100 to 300 nanometers. The material of the isolation layer 520 includes, for example, AlN, and the thickness of the isolation layer 520 is, for example, 1 to 2 nanometers. The isolation layer 520 is provided to improve the luminescence performance of the second epitaxial structure 500. The material of the barrier layer 530 includes, for example, AlGaN, and the proportion of aluminum in the barrier layer 530 is 20% to 30%, and the thickness of the barrier layer 530 is, for example, 15 to 30 nanometers. The AlGaN in the barrier layer 530 forms a heterostructure with the GaN in the electron channel layer 510, thereby obtaining 2-DEG (Two-dimensional electron gas). In this way, the light-emitting device 10 provided in the embodiment of the present invention can achieve the effect of constant current light emission.

[0034] By setting an isolation layer 520 (AlN thin layer) between the barrier layer 530 (AlGaN) and the electron channel layer 510 (GaN), the electron density of the two-dimensional electron gas can be increased, the resistance can be reduced, the mobility can be increased, and a larger current can be achieved. Specifically, the effective ΔEc (cathode polarization value) caused by the polarization effect of the AlGaN / AlN / GaN structure is increased, a deeper quantum well is generated, and thus a higher electron concentration is generated; the penetration of the two-dimensional electron gas into the barrier layer 530 is significantly reduced, so the alloy disorder scattering can be reduced and the mobility can be improved. That is, the AlGaN / AlN / GaN heterojunction formed by inserting an AlN thin layer at the AlGaN / GaN heterojunction interface is superior to the conventional AlGaN / GaN heterojunction.

[0035] In addition, the light emitting device 10 further includes, for example, a surface protection layer 600, which includes, for example, a protection layer and / or a passivation layer. For example, a protection layer may be provided on the side of the barrier layer 530 away from the isolation layer 520, the material of the protection layer may be, for example, GaN, and the thickness of the protection layer may be, for example, 2 nanometers; or a passivation layer may be provided on the side of the barrier layer 530 away from the isolation layer 520, the material of the passivation layer may be, for example, SiN, and the thickness of the passivation layer may be, for example, 10 to 50 nanometers; or a protection layer may be provided on the side of the barrier layer 530 away from the isolation layer 520, and a passivation layer may be provided on the protection layer.

[0036] To sum up, the embodiment of the present invention avoids affecting the mobility of the second epitaxial structure, avoids leakage of the second epitaxial structure, and avoids diffusion of Mg in the first epitaxial structure into the second epitaxial structure by setting a flat and high-resistance GaN connecting layer, thereby integrating the two epitaxial structures into one light-emitting device, so that the light-emitting device provided by the embodiment of the present invention not only realizes light emission but also realizes constant current light emission, which can more flexibly solve the problem of uneven brightness of the head and tail of the existing long-line LED filaments / light strips; and based on the integration of the two epitaxial structures into one light-emitting device, the light-emitting device provided by the embodiment of the present invention can be more flexibly applied to light-emitting devices that require constant current.

[0037] [Second embodiment]

[0038] Compared with the first embodiment, the light emitting device 10 of the second embodiment is based on the same idea but has slightly different specific structural settings and specific parameters of some layers. The differences between the second embodiment and the first embodiment are illustrated below, and the similarities are not repeated.

[0039] For details, see Figure 4 The light emitting device 10 provided in the second embodiment of the present invention, for example, comprises: a substrate 100, a buffer layer 200, a second epitaxial structure 500, a connecting layer 400 and a first epitaxial structure 300. The buffer layer 200 is, for example, disposed on one side of the substrate 100, the second epitaxial structure 500 is, for example, disposed on a side of the buffer layer 200 away from the substrate 100, the connecting layer 400 is, for example, disposed on a side of the second epitaxial structure 500 away from the buffer layer 200, and the first epitaxial structure 300 is, for example, disposed on a side of the connecting layer 400 away from the second epitaxial structure 500.

[0040] In the second embodiment, the second buffer layer 220 may be different from the first embodiment. The second buffer layer 220 may be a high-resistance layer structure. For example, the resistance of the second buffer layer 220 is 1.17e11Ω / □. The material of the second buffer layer is GaN, and the high-resistance second buffer layer 220 is obtained by growing the second buffer layer 220 under conditions such as epitaxial GaN flow field and temperature field, or the material of the second buffer layer 320 is Fe- or C-doped GaN, wherein the doping concentration is greater than 1e19cm -3 The thickness of the second buffer layer 220 is, for example, 2 to 4 micrometers. The second buffer layer 220 is, for example, grown at a temperature of 1000 to 1150° C. on a side of the first buffer layer 321 away from the substrate 100. By providing a high-resistance second buffer layer 220, the breakdown voltage can be increased to prevent leakage of the light-emitting device 10.

[0041] Further, see Figure 5The second epitaxial structure 500, for example, includes an electron channel layer 510, an isolation layer 520, and a barrier layer 530 arranged in sequence, wherein the electron channel layer 510 is, for example, arranged on a side of the second buffer layer 220 away from the first buffer layer 210, and the material of the barrier layer 530 includes AlGaN.

[0042] Based on the above, the specific parameters of the connection layer 400 in the second embodiment are different from those in the first embodiment. The connection layer 400 is, for example, disposed on the side of the barrier layer 530 away from the isolation layer 520. The material of the connection layer 400 includes GaN, and the connection layer 400 is, for example, a flat high-resistance layer structure. If the barrier layer 530 has a high Al component (the proportion of aluminum is greater than 25%) or the thickness of the barrier layer 530 is thicker (the thickness is greater than 9 nanometers), the epitaxial surface of the second epitaxial structure 500 is prone to become rough. For example, the roughness of the side of the second epitaxial structure 500 away from the substrate 100 is, for example, 0.3 to 0.5 nanometers, and the roughness of the connection layer 400 is, for example, less than 0.3 nanometers. Preferably, the roughness of the connection layer 400 is, for example, 0.22 nanometers, and the resistance Rs of the connection layer 400 is, for example, greater than 1e9Ω / □. Furthermore, the thickness of the connecting layer 400 is, for example, greater than 100 nanometers, and the preferred thickness of the connecting layer 400 is, for example, 200 to 800 nanometers. If the thickness of the connecting layer 400 is less than 100 nanometers, the Si in the first epitaxial structure 300 may penetrate into the second epitaxial structure 500 due to the insufficient thickness of the connecting layer 400, thereby causing the current collapse effect of the second epitaxial structure 500. If the thickness of the connecting layer 400 is greater than 800 nanometers, the warping may be too large due to excessive thickness. The connecting layer 400 is grown, for example, at a temperature of 1000 to 1100° C. on the side of the barrier layer 530 away from the substrate 100. The connecting layer 400 grown at high temperature can play a barrier role, thereby reducing dislocation pits and preventing leakage, thereby improving the electrical performance of the light-emitting device 10.

[0043] Further, see Figure 5 The first epitaxial structure 300, for example, includes an N-type GaN layer 310, a stress adjustment layer 320, a light-emitting layer 330, an electron blocking layer 340 and a P-type GaN layer 350 arranged in sequence, wherein the N-type GaN layer 310 is, for example, arranged on a side of the connecting layer 400 away from the barrier layer 530.

[0044] To summarize, the embodiment of the present invention sets the thickness of the connecting layer to be greater than 100 nanometers, thereby avoiding the Si in the first epitaxial structure 300 from penetrating into the second epitaxial structure due to insufficient thickness of the connecting layer, thereby causing the current collapse effect of the second epitaxial structure, and also avoiding warping due to excessive thickness of the connecting layer; and the connecting layer grown at high temperature can play a barrier role, thereby reducing dislocation pits and preventing leakage, thereby improving the electrical performance of the light-emitting device 10; in this way, the two epitaxial structures are integrated into one light-emitting device, so that the light-emitting device provided by the embodiment of the present invention not only realizes light emission but also realizes constant current light emission, which can more flexibly solve the problem of uneven brightness of the head and tail of the existing long-line LED filament / light strip, and based on the integration of the two epitaxial structures into one light-emitting device, the light-emitting device provided by the embodiment of the present invention can be more flexibly applied to light-emitting devices requiring constant current.

[0045] In addition, see Figure 6 The following is a method for preparing the light emitting device 10 provided in the first embodiment of the present application, and the preparation method includes, for example:

[0046] S11: providing a substrate;

[0047] S13: growing an N-type GaN layer, a light-emitting layer and a P-type GaN layer in sequence on the substrate;

[0048] S15: growing a connection layer on the P-type GaN layer;

[0049] S17: sequentially growing an electron channel layer, an isolation layer and a barrier layer on the connection layer.

[0050] Wherein, step S11 specifically includes: growing AlN on a sapphire substrate by a plasma enhanced chemical vapor phase method, and heat treating it in a hydrogen environment at 1000-1200° C. for 8-12 minutes to obtain a substrate liner;

[0051] Step S12 is also included between step S11 and step S13, and step S12 specifically includes:

[0052] S121: growing an AlN buffer layer on a substrate liner by metal organic chemical vapor deposition,

[0053] S123: growing a GaN buffer layer on the AlN buffer layer at low temperature;

[0054] S125: growing a second buffer layer on the GaN buffer layer at a temperature of 1000-1150° C.

[0055] Based on the above, step S13 specifically includes:

[0056] S131: growing an N-type GaN layer on the second buffer layer;

[0057] S132: growing a stress adjustment layer on the N-type GaN layer at a temperature of 750 to 950° C.;

[0058] S133: growing a light-emitting layer on the stress adjustment layer;

[0059] S134: growing an electron blocking layer on the light-emitting layer;

[0060] S135: growing a P-type GaN layer on the electron blocking layer.

[0061] Among them, step S133 is to grow a light-emitting layer on the stress adjustment layer in an environment where N2 (nitrogen) is the main carrier gas, and TMGa / TEGa (trimethylgallium / triethylgallium), TMAl (trimethylaluminum), TMIn (trimethylindium) and NH3 (ammonia) are used as Ga source, Al source, In source and N source respectively, wherein the material of the connecting layer includes Fe and / or C-doped GaN to obtain a flat high-resistance connecting layer.

[0062] Step S15 specifically includes: growing the connection layer on the barrier layer under the conditions of epitaxial GaN flow field and temperature field.

[0063] Furthermore, step S17 specifically includes:

[0064] S171: growing an electron channel layer on the connecting layer;

[0065] S173: growing an isolation layer on the electron channel layer;

[0066] S175: growing a barrier layer on the isolation layer.

[0067] In addition, step S19 is included after step S17, and step S19 specifically includes:

[0068] S191: growing a protective layer on the barrier layer;

[0069] S193: growing a passivation layer on the protective layer.

[0070] In addition, see Figure 7 , for example, a method for preparing the light emitting device 10 provided in the second embodiment of the present application is also provided, and the preparation method, for example, includes:

[0071] S21: providing a substrate;

[0072] S23: growing an electron channel layer, an isolation layer and a barrier layer in sequence on the substrate;

[0073] S25: growing a connection layer on the barrier layer;

[0074] S27: sequentially growing an N-type GaN layer, a light-emitting layer and a P-type GaN layer on the connection layer.

[0075] Here, step S21 is, for example, the same as step S11.

[0076] Step S22 is also included between step S21 and step S23, and step S22 specifically includes:

[0077] S221: growing an AlN buffer layer on a substrate liner by metal organic chemical vapor deposition,

[0078] S223: growing a GaN buffer layer on the AlN buffer layer at low temperature;

[0079] S225: growing a second buffer layer on the GaN buffer layer at a temperature of 1000-1150° C. and under epitaxial GaN flow field and temperature field conditions.

[0080] Based on the above, step S23 specifically includes:

[0081] S231: growing an electron channel layer on the second buffer layer;

[0082] S233: growing an isolation layer on the electron channel layer;

[0083] S235: growing a barrier layer on the isolation layer.

[0084] Step S25 specifically includes: growing the connection layer on the barrier layer at a temperature of 1000-1100° C.

[0085] Step S27 specifically includes:

[0086] S271: growing an N-type GaN layer on the connection layer;

[0087] S272: growing a stress adjustment layer on the N-type GaN layer at a temperature of 750 to 950° C.;

[0088] S273: growing a light-emitting layer on the stress adjustment layer;

[0089] S274: growing an electron blocking layer on the light-emitting layer;

[0090] S275: growing a P-type GaN layer on the electron blocking layer.

[0091] It can be understood that the aforementioned embodiments are only exemplary descriptions of the present invention. Under the premise that the technical features do not conflict, the structures do not contradict, and the purpose of the present invention is not violated, the technical solutions of the various embodiments can be arbitrarily combined and used in combination.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light emitting device, characterized in that: include: The first epitaxial structure includes an N-type GaN layer, a light-emitting layer and a P-type GaN layer arranged in sequence; A second epitaxial structure includes an electron channel layer and a barrier layer arranged in sequence; and Connection layer; The connection layer is connected between the first epitaxial structure and the second epitaxial structure, and the material of the connection layer includes GaN.

2. The light emitting device according to claim 1, characterized in that: Also includes: substrate; The first epitaxial structure is arranged on one side of the substrate, the connecting layer is arranged on a side of the first epitaxial structure away from the substrate, and the second epitaxial structure is arranged on a side of the connecting layer away from the first epitaxial structure.

3. The light emitting device according to claim 2, characterized in that: The connecting layer is an undoped GaN layer; or, the connecting layer is a Fe and / or C-doped GaN layer, and the doping concentration of the connecting layer is greater than 8e18cm -3 .

4. The light emitting device according to claim 3, characterized in that: The N-type GaN layer is disposed on one side of the substrate, the light-emitting layer is disposed on a side of the N-type GaN layer away from the substrate, the P-type GaN layer is disposed on a side of the light-emitting layer away from the N-type GaN layer, and the connecting layer is disposed on a side of the P-type GaN layer away from the light-emitting layer; The material of the P-type GaN layer includes Mg-doped GaN; The electron channel layer is arranged on a side of the connection layer away from the P-type GaN layer, and the barrier layer is arranged on a side of the electron channel layer away from the connection layer; wherein the material of the electron channel layer includes GaN or InGaN.

5. The light emitting device according to claim 1, characterized in that: Also includes: substrate; The second epitaxial structure is arranged on one side of the substrate, the connecting layer is arranged on a side of the second epitaxial structure away from the substrate, and the first epitaxial structure is arranged on a side of the connecting layer away from the second epitaxial structure.

6. The light emitting device according to claim 5, characterized in that: The barrier layer is arranged on one side of the substrate, the electron channel layer is arranged on a side of the barrier layer away from the substrate, and the connection layer is arranged on a side of the electron channel layer away from the barrier layer; wherein the material of the barrier layer includes AlGaN.

7. The light emitting device according to claim 6, characterized in that: The N-type GaN layer is arranged on a side of the connecting layer away from the barrier layer, the light-emitting layer is arranged on a side of the N-type GaN layer away from the connecting layer, and the P-type GaN layer is arranged on a side of the light-emitting layer away from the N-type GaN layer; the material of the N-type GaN layer includes Si-doped GaN, and the doping concentration range of the N-type GaN layer is 1e19cm -3 ~3e19cm -3 .

8. The light emitting device according to any one of claims 1 to 7, characterized in that: The thickness of the connecting layer is greater than 100 nanometers.

9. The light emitting device according to any one of claims 1 to 7, characterized in that: The second epitaxial structure further includes an isolation layer, wherein the isolation layer is connected between the electron channel layer and the barrier layer, the material of the isolation layer includes AlN, and the thickness of the isolation layer is 1 to 2 nanometers.

10. A light emitting device, characterized in that: include: A substrate, a connecting layer, a first epitaxial structure, and a second epitaxial structure; One of the first epitaxial structure and the second epitaxial structure is disposed between the substrate and the connection layer, and the other of the first epitaxial structure and the second epitaxial structure is disposed on a side of the connection layer away from the substrate; The roughness of a side of the connecting layer away from the substrate is smaller than the roughness of a side of the first epitaxial structure or the second epitaxial structure disposed on the substrate away from the substrate.

Images