Light emitting diode epitaxial structure

Abstract

The utility model discloses a light-emitting diode epitaxial structure, which comprises a substrate, an electron providing layer, a light-emitting layer and a hole providing layer which are sequentially arranged from bottom to top, and a miniature capacitor layer is added between the electron providing layer and the light-emitting layer. The micro capacitor layer comprises more than one layer of micro capacitor structure, the micro capacitor structure is composed of a GaN: C / GaN: Si structure, the GaN: C is on the upper part, and the GaN: Si is on the lower part. Due to the existence of the capacitance effect, the structure buffers the electron migration rate, solves the problem that the electron hole migration rates are not matched, and further improves the luminous efficiency; moreover, the structure can absorb and disperse electrostatic energy, weaken the influence of instantaneous voltage impact and current peak on the LED structure, and stabilize the working voltage and current, thereby improving the antistatic capability of the LED epitaxial structure.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor materials and photoelectric device preparation processes, in particular to a light emitting diode epitaxial structure. Background Art

[0002] Light-emitting diodes (LEDs) are known as the third generation of lighting sources after incandescent lamps and fluorescent lamps. LED technology has the characteristics of energy saving, environmental protection, and long life, which has attracted widespread attention from the industry and academia. Semiconductor lighting technology is changing with each passing day, and the increasing lumen efficiency has enabled LEDs to have more applications. LEDs have gradually moved from traditional indicator lights to backlighting, lighting, and display applications. With the successful commercialization of LEDs, they have been widely used in many fields such as traffic lights, full-color displays, LCD backlights, and white light LEDs. With the continuous expansion of application areas, the reliability requirements of devices are constantly increasing. Due to the insulating properties of sapphire substrates, GaN-based LEDs are often damaged by electrostatic discharge (ESD), resulting in reduced device performance, reduced service life, or even complete destruction. Therefore, improving the anti-electrostatic discharge performance of light-emitting diodes has an important impact on the reliability of devices.

[0003] There are two main basic ideas for improving the ESD performance of GaN-based LEDs: one is to add a parallel shunt circuit to the device to reduce the current flowing through the device during electrostatic discharge; the other is to improve the crystal quality of GaN materials, reduce defect density, enhance the current expansion effect, and obtain a more uniform and smaller local current density. For the former, it can be achieved by integrating a silicon Zener diode (Si-based Zener Diode) through a flip-chip process or making a built-in GaN-based Schottky diode (Schottky Diode). Although these methods can achieve the purpose of improving the ESD performance of light-emitting diodes, they will increase the process complexity and increase production costs. Utility Model Content

[0004] The purpose of the utility model is to provide a light emitting diode epitaxial structure to solve the problems mentioned in the above background technology.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] A light-emitting diode epitaxial structure comprises an AlO-SiO composite substrate, an electron supply layer formed by Si-doped GaN, a superlattice structure light-emitting layer formed by a combination of GaN / InGaN / AlGaN, and a hole supply layer formed by highly Mg-doped GaN, which are arranged in sequence from bottom to top. A micro-capacitor layer is added between the electron supply layer and the light-emitting layer. The micro-capacitor layer comprises more than one micro-capacitor structure, and the micro-capacitor structure consists of a GaN:C / GaN:Si structure, wherein GaN:C is on the top and GaN:Si is on the bottom.

[0007] Specifically, the micro capacitor layer is composed of four sub-capacitor layers, which are stacked in sequence from bottom to top: a first sub-capacitor layer, a second sub-capacitor layer, a third sub-capacitor layer, and a fourth sub-capacitor layer.

[0008] Preferably, a GaN buffer layer is provided between the composite substrate and the electron supply layer.

[0009] Preferably, a current spreading layer formed of low-doped GaN is provided between the electron supply layer and the micro-capacitor layer or between the micro-capacitor layer and the light-emitting layer.

[0010] Preferably, a superlattice structure stress release layer formed by a combination of GaN and InGaN is arranged between the electron supply layer and the micro capacitor layer or between the micro capacitor layer and the light emitting layer.

[0011] Preferably, an electron blocking layer having a superlattice structure composed of AlN / AlGaN / GaN is arranged between the light-emitting layer and the hole-supplying layer.

[0012] Preferably, the light-emitting diode epitaxial structure is provided with at least two of a buffer layer, a current spreading layer, a stress release layer, and an electron blocking layer; when present: the buffer layer is arranged between the substrate and the electron supply layer; the current spreading layer and the stress release layer are arranged between the electron supply layer and the light-emitting layer, and the positions of the current spreading layer, the micro-capacitor layer, and the stress release layer can be arbitrarily interchanged or the structures can be integrated; the electron blocking layer is arranged between the light-emitting layer and the hole supply layer.

[0013] The GaN:C is highly C-doped GaN, and the GaN:Si is highly Si-doped GaN.

[0014] The C element in the highly C-doped GaN layer can be obtained by changing the growth conditions (such as high growth rate, low growth pressure, low growth temperature or low 5:3 ratio), by introducing a C source (CCl 4 \CBr 4 Since changing the growth conditions will lead to a decrease in the quality of the crystal, it is preferred to introduce CBr 4A highly C-doped GaN is obtained, wherein the C-doping concentration is higher than the C-doping concentration of the highly Si-doped GaN layer. The Si element in the highly Si-doped GaN layer is provided by a Si source, preferably SiH 4 , the Si doping concentration is higher than that of the highly C-doped GaN layer.

[0015] The utility model sets a micro capacitor structure between the electron supply layer and the light-emitting layer, and a capacitor is formed by high C-doped GaN and high Si-doped GaN, and the capacitor structure is cyclically grown to form multiple capacitors to form a micro capacitor structure. Since high C-doped GaN has high resistance and exhibits P-type GaN characteristics, it can form a capacitor effect when combined with high Si-doped GaN exhibiting N-type GaN characteristics.

[0016] Due to the existence of the capacitance effect, the structure of the utility model buffers the electron migration rate, solves the problem of electron-hole migration rate mismatch, and thus improves the luminous efficiency; and the structure can also absorb and disperse electrostatic energy, weaken the impact of instantaneous voltage shock and current peak on the LED structure, stabilize the operating voltage and current, and thus improve the anti-static ability of the LED epitaxial structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the SIMS (secondary ion mass spectrometry) of In, C, and Si elements of an LED epitaxial wafer containing a micro-capacitor structure. The area framed by the square is the SIMS of C and Si elements of the micro-capacitor structure GaN:C / GaN:Si.

[0018] Figure 2 It is a schematic diagram of the epitaxial structure of the light emitting diode of the utility model provided in Example 1. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. The components of the embodiment of the utility model generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the utility model provided in the drawings is not intended to limit the scope of the utility model for protection, but merely represents the selected embodiment of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0020] Example:

[0021] like Figure 2The light emitting diode epitaxial structure of the present embodiment shown includes a substrate 100, a buffer layer 200, an electron supply layer 300, a current spreading layer 400, a micro capacitor layer 500, a stress release layer 600, a light emitting layer 700, an electron blocking layer 800, and a hole supply layer 900 arranged in sequence from bottom to top;

[0022] Provide an Al 2 O 3 -SiO 2 Composite substrate;

[0023] A GaN buffer layer 200 is deposited on the substrate with a thickness of 4 μm;

[0024] An electron supply layer 300 is deposited on the buffer layer; the electron supply layer is a Si-doped GaN layer with a Si concentration of 2E19 atom / cm 3 , thickness 1.5um;

[0025] A current spreading layer 400 is deposited on the electron supply layer. The current spreading layer is a low-doped GaN layer with a Si concentration of 2E17atom / cm 3 , thickness 0.25um;

[0026] Depositing a micro capacitor layer 500 on the current spreading layer;

[0027] The microcapacitor layer is composed of 4 subcapacitor layers;

[0028] The sub-capacitor layer is stacked with a high Si-doped GaN layer and a high C-doped GaN layer from bottom to top;

[0029] The highly Si-doped GaN layer in the sub-capacitor layer can have inconsistent thickness and inconsistent doping;

[0030] The highly C-doped GaN layer in the sub-capacitor layer can have inconsistent thickness and inconsistent doping;

[0031] In this embodiment, the micro capacitor layer is composed of four sub-capacitor layers, which are stacked from bottom to top in sequence: a first sub-capacitor layer 510, a second sub-capacitor layer 520, a third sub-capacitor layer 530, and a fourth sub-capacitor layer 540;

[0032] The first sub-capacitor layer is deposited on the current spreading layer; it is composed of a highly Si-doped GaN layer 511 and a highly C-doped GaN layer 512;

[0033] High Si-doped GaN layer is formed by controlling the introduction of SiH 4 The amount of Si doping is controlled by the amount of Si doping, 1E18 atom / cm 3 , thickness 0.05um, C doping 3E16 atom / cm 3 ;

[0034] Highly C-doped GaN layer is formed by controlling the introduction of CBr 4 The amount of C doping is controlled by the amount of C doping, 3E17 atom / cm 3 , thickness 0.05um, Si doping 1E17 atom / cm 3 ;

[0035] The second sub-capacitor layer is deposited on the first sub-capacitor layer; it is composed of a second highly Si-doped GaN layer 521 and a second highly C-doped GaN layer 522;

[0036] The highly Si-doped GaN layer is formed by controlling the introduction of SiH 4 The amount of Si doping is controlled by the amount of Si doping, 2E18 atom / cm 3 , thickness 0.05um, C doping 2E16 atom / cm 3 ;

[0037] The highly C-doped GaN layer is then controlled by introducing CBr 4 The amount of C doping is controlled by the amount of C doping, 5E17 atom / cm 3 , thickness 0.05um, Si doping 8E16 atom / cm 3 ;

[0038] The third sub-capacitor layer is deposited on the second sub-capacitor layer; it is composed of a third highly Si-doped GaN layer 531 and a third highly C-doped GaN layer 532;

[0039] High Si-doped GaN layer is three-way controlled to introduce SiH 4 The amount of Si doping is controlled by the amount of Si doping, 3E18 atom / cm 3 , thickness 0.05um, C doping 1E16 atom / cm 3 ;

[0040] Highly C-doped GaN layer is three-way controlled by CBr 4 The amount of C doping is controlled by the amount of C doping, 7E17 atom / cm 3 , thickness 0.05um, Si doping 6E16 atom / cm 3 ;

[0041] The fourth sub-capacitor layer is deposited on the third sub-capacitor layer; it is composed of a highly Si-doped GaN layer 541 and a highly C-doped GaN layer 542;

[0042] High Si-doped GaN layer is four-way controlled by introducing SiH 4 The amount of Si doping is controlled by the amount of Si doping, 5E18 atom / cm 3 , thickness 0.05um, C doping 1E16 atom / cm 3 ;

[0043] Highly C-doped GaN layer is four-way controlled by introducing CBr 4 The amount of C doping is controlled by the amount of C doping, 1E18 atom / cm 3 , thickness 0.05um, Si doping 4E16 atom / cm 3 ;

[0044] A stress release layer 600 is deposited on the micro capacitor layer. The stress release layer is a super lattice structure formed by a combination of GaN and InGaN, and has a thickness of 0.2 um.

[0045] A light emitting layer 700 is deposited on the stress release layer. The light emitting layer is a super lattice structure formed by a combination of GaN / InGaN / AlGaN and has a thickness of 0.2 um.

[0046] An electron blocking layer 800 is deposited on the light emitting layer. The electron blocking layer is a super lattice structure composed of AlN / AlGaN / GaN and has a thickness of 150A.

[0047] A hole supply layer 900 is deposited on the electron blocking layer, and the hole supply layer is a highly Mg-doped GaN layer.

[0048] In the description of the present utility model, it should be noted that when terms such as "upper", "lower", "inner", "outer", "left", "right" and the like indicating orientation or positional relationship appear, it should be understood that the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the utility model product is usually placed when in use, or the orientation or positional relationship commonly understood by those skilled in the art, is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the equipment or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, when terms such as "first" and "second" appear, they are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present utility model, it should also be noted that, unless otherwise clearly specified and limited, terms such as "installation", "setting", and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements. For those skilled in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

Claims

1. A light-emitting diode epitaxial structure, comprising, arranged in order from bottom to top, an Al2O3-SiO2 composite substrate (100), an electron supply layer (300) formed of Si-doped GaN, a superlattice structure light-emitting layer (700) formed of a combination of GaN / InGaN / AlGaN, and a hole supply layer (900) formed of highly Mg-doped GaN, characterized in that: A micro capacitor layer (500) is added between the electron supply layer (300) and the light-emitting layer (700), wherein the micro capacitor layer comprises more than one layer of micro capacitor structure, and the micro capacitor structure is composed of a GaN:C / GaN:Si structure, wherein GaN: C is on top and GaN:Si is on the bottom.

2. The light emitting diode epitaxial structure according to claim 1, characterized in that: The micro capacitor layer is composed of four sub-capacitor layers, which are stacked in sequence from bottom to top: a first sub-capacitor layer (510), a second sub-capacitor layer (520), a third sub-capacitor layer (530), and a fourth sub-capacitor layer (540).

3. The light emitting diode epitaxial structure according to claim 1 or 2, characterized in that: A GaN buffer layer (200) is provided between the composite substrate (100) and the electron supply layer (300).

4. The light emitting diode epitaxial structure according to claim 1 or 2, characterized in that: A current spreading layer (400) formed of low-doped GaN is provided between the electron supply layer (300) and the micro-capacitor layer (500) or between the micro-capacitor layer (500) and the light-emitting layer (700).

5. The light emitting diode epitaxial structure according to claim 1 or 2, characterized in that: A superlattice structure stress release layer (600) formed by a combination of GaN and InGaN is provided between the electron supply layer (300) and the micro capacitor layer (500) or between the micro capacitor layer (500) and the light emitting layer (700).

6. The light emitting diode epitaxial structure according to claim 1 or 2, characterized in that: An electron blocking layer (800) having a superlattice structure composed of AlN / AlGaN / GaN is arranged between the light-emitting layer (700) and the hole-supplying layer (900).

7. The light emitting diode epitaxial structure according to claim 1 or 2, characterized in that: At least two of a buffer layer (200), a current spreading layer (400), a stress release layer (600), and an electron blocking layer (800) are provided; when present: the buffer layer (200) is provided between the substrate (100) and the electron supply layer (300); the current spreading layer (400) and the stress release layer (600) are provided between the electron supply layer (300) and the light-emitting layer (700), and the positions of the current spreading layer (400), the micro-capacitor layer (500), and the stress release layer (600) can be interchanged at will or their structures can be integrated; and the electron blocking layer (800) is provided between the light-emitting layer (700) and the hole supply layer (900).

Images