WO2014101649A1 - Nitride light emitting diode - Google Patents

Abstract

Provided is a nitride light emitting diode having a local doped p-type limit structure, comprising a n-type layer (102), an active layer (103), and p-type layer (105) formed of a nitride semiconductor, a p-type limit structure (104) being further provided between the p-type layer and the active layer, where the p-type limit structure is a multi-layer structure, whose end portion in contact with the active layer is an aluminum indium gallium nitride material layer (104a), the aluminum indium gallium nitride material layer being locally doped, and whose surface in contact with the active layer is not doped. Therefore, light emitting efficiency is improved, and low voltage and desirable aging characteristic are provided.

Description

 Nitride light emitting diode

This application claims the following priority: Chinese invention patent application number 201210582149.6, entitled ' The nitride light-emitting diode ' was submitted on December 28, 2012. The entire contents of the above application are incorporated herein by reference.

Technical field

 The present invention relates to a nitride light emitting diode assembly having a p-type confinement structure, specifically an active layer and p A nitride light-emitting diode partially doped with a p-type confinement structure is formed between the layers.

Background technique

As the efficiency of power GaN-based LEDs continues to increase, the replacement of existing illumination sources with GaN-based LED semiconductor lamps will be an unstoppable trend. However, semiconductor lighting has to enter thousands of households, and there are still many problems to be solved. The most important issues include luminous efficiency and reliability.

Summary of the invention

 The invention proposes a partial doping p A nitride-emitting diode of a limited structure, which improves luminous efficiency and has a lower voltage and better aging characteristics.

The technical solution adopted by the present invention to solve the above problems is: a nitride light emitting diode comprising an n-type layer formed of a nitride semiconductor, an active layer, and p a p-type confinement structure between the p-type layer and the active layer, characterized in that: The type confinement structure is a multi-layer structure, and the end portion in contact with the active layer is an aluminum indium gallium nitride material layer, the aluminum indium gallium nitride material layer is partially doped, and the contact surface with the active layer is undoped.

Preferably, the p-type confinement structure has a thickness of 50 angstroms to 3000 The thickness of the end aluminum nitride indium gallium material layer in contact with the active layer is 5 Å to 150 Å.

Preferably, the aluminum indium gallium nitride material layer is partially doped with Mg and has a doping concentration greater than 1 × 10 ¹⁷ cm ^-3 . In some embodiments of the present invention, in the end aluminum nitride indium gallium material layer in contact with the active layer, the Mg doping position is at the middle or the second half of the end aluminum nitride indium gallium nitride material layer. . In some embodiments of the present invention, in the end aluminum nitride indium gallium material layer in contact with the active layer, the Mg doping has a Gaussian distribution, wherein the contact surface with the active layer is undoped. In some embodiments of the present invention, in the end aluminum nitride indium gallium material layer in contact with the active layer, the Mg-doped aluminum indium gallium nitride material layer has a thickness less than the aluminum indium gallium nitride material. 1/2 of the layer.

In some embodiments of the present invention, the P-type confinement structure further includes: an indium gallium nitride and a second aluminum indium gallium nitride stack deposited on the end layer of aluminum indium gallium nitride material. Wherein, the first aluminum indium gallium nitride Al _x In _y Ga _1-xy N film having a thickness in contact with the active layer is 5 angstroms to 150 angstroms, 0 < x < 0.3, 0 ≦ y < 0.3, Mg doping For local doping. Preferably, the first aluminum indium gallium nitride has a thickness of 60 angstroms to 120 angstroms, 0.05 ≦ x ≦ 0.2, 0 ≦ y ≦ 0.15, uniformly doped Mg from the middle of the first aluminum indium gallium nitride, and the doping thickness It is 1/3 of the thickness of the first aluminum indium gallium nitride film, and the doping concentration is greater than 5 × 10 ¹⁸ cm ^-3 . The indium gallium nitride In _z Ga _1-z N film has a thickness of 10 Å to 800 Å, and 0 < z < 0.4, preferably an indium gallium nitride film having a thickness of 50 Å to 600 Å and 0.2 ≦ z ≦ 0.3 . The second aluminum indium gallium nitride Al _x InyGa _1-xy N film thickness is 35 Å to 2050 Å, 0 < x < 0.3, 0 ≦ y < 0.3, and the second aluminum indium gallium nitride film thickness is preferably selected to be 100 Å. 600 angstroms, 0.05 ≦ x ≦ 0.2 , 0 ≦ y ≦ 0.15 .

In the p-type confinement structure of the present invention, the position, the thickness, and the number of the first doped first aluminum indium gallium nitride layer doping are moderate, thereby blocking the diffusion of Mg and increasing the effective injection of holes. The luminous efficiency, forward voltage, and aging characteristics of the nitride light emitting diode assembly, and thus the present invention can be applied to applications requiring higher luminous efficiency and aging characteristics.

DRAWINGS

1 is a schematic cross-sectional view of a nitride light emitting diode module according to an embodiment of the present invention.

Fig. 2 is a view showing the Mg doping concentration of the nitride light emitting diode device according to Embodiment 1 of the present invention.

Fig. 3 is a view showing the Mg doping concentration of the nitride light emitting diode device according to Embodiment 2 of the present invention.

Fig. 4 is a view showing the Mg doping concentration of the nitride light emitting diode device of Embodiment 3 of the present invention.

Fig. 5 is a graph showing the luminous output power of the embodiment 1 of the present invention.

Figure 6 is a graph showing the forward current - forward voltage of Embodiment 1 of the present invention.

Fig. 7 is a graph showing the long-term aging light decay of the embodiment 1 of the present invention.

Fig. 8 is a graph showing the long-term aging leakage current of the embodiment 1 of the present invention.

Figure 9 is a graph showing the luminous output power of Embodiment 2 of the present invention.

Figure 10 is a graph showing the forward current - forward voltage of Embodiment 2 of the present invention.

Figure 11 is a graph showing the long-term aging light decay of Example 2 of the present invention.

Figure 12 is a graph showing the long-term aging leakage current of Example 2 of the present invention.

Figure 13 is a graph showing the luminous output power of Embodiment 3 of the present invention.

Figure 14 is a graph showing the forward current - forward voltage of Embodiment 3 of the present invention.

Figure 15 is a graph showing the long-term aging light decay of Example 3 of the present invention.

Figure 16 is a graph showing the long-term aging leakage current of Example 3 of the present invention.

In the picture:

100. sapphire substrate ;

 101. a buffer layer;

 102.n type layer;

 103. active layer;

 104. p type restriction structure;

 104a. a first aluminum indium gallium nitride;

 104b. Indium gallium nitride;

 104c. a second aluminum indium gallium nitride;

 105.p type layer;

 106. p type contact layer;

 107.p ohmic electrode;

 108.n ohmic electrode;

109.p pad electrode.

detailed description

 The following embodiments disclose a nitride light emitting diode having a p-type confinement structure, wherein p The type limiting structure is located between the active layer and the p-type layer, and has a multi-layer structure, and one end in contact with the active layer is an aluminum indium gallium nitride material layer, and the aluminum indium gallium nitride material layer is partially doped and active layer The contact surface is undoped.

The invention will now be further described with reference to the drawings and embodiments.

1 is a schematic cross-sectional view showing the structure of a nitride light emitting diode assembly (LED module) according to an embodiment of the present invention, The nitride light emitting diode module of the present embodiment has a structure in which the following layers are sequentially laminated on the sapphire substrate 100:

 (1) A buffer layer composed of gallium nitride (GaN), aluminum nitride (AlN) or aluminum gallium nitride (GaAlN) 101 , the film thickness is 200 angstroms to 500 angstroms;

 (2) An n-type layer 102 composed of Si-doped GaN having a film thickness of 20,000 Å to 40,000 埃

 (3) An active layer of a multiple quantum well structure in which an InGaN layer is used as a well layer and a GaN layer is used as a barrier layer. The film thickness of the well layer is 18 angstroms to 30 angstroms, and the film thickness of the barrier layer is 80 angstroms to 200 angstroms;

 (4) Local doping consisting of a combination of Mg-doped aluminum indium gallium nitride (AlInGaN) and indium gallium nitride (InGaN) The p-type confinement structure 104 has a film thickness of 50 angstroms to 3000 angstroms; the doping mode can be formed by MOCVD epitaxial growth method;

 (5) p-type layer 105 consisting of one of gallium nitride (GaN), indium gallium nitride (InGaN) or gallium nitride The contact layer 106 has a p-type layer 105 having a film thickness of 1000 Å to 3000 Å, and a p-type contact layer 106 having a film thickness of 50 Å to 200 Å.

The electrodes on the p side and the n side can be formed in the following manner, thereby constituting a nitride light emitting diode assembly. First, etch from the corners of the assembly from p The portion of the contact layer 106 to the n-type layer 102 is removed, a portion of the n-type layer 102 is exposed, and an n-ohmic electrode 108 is formed on the exposed n-type layer 102; An electrode on the p-side, specifically, a p-ohmic electrode 107 is formed on almost the entire surface of the p-type contact layer 106, and a p-pad is formed on a portion of the p-ohmic electrode 107. Electrode 109.

The nitride light emitting diode assembly of the present embodiment is characterized by being combined with Mg-doped aluminum indium gallium nitride (Al _x In _y Ga _1-xy N) and indium gallium nitride (In _z Ga _1-z N). The partially doped p-type confinement structure 104 is configured to improve the luminous efficiency of the nitride light-emitting diode, reduce the forward voltage, and have excellent aging characteristics.

In the present embodiment, the partially doped p-type confinement structure 104 includes a first aluminum indium gallium nitride layer 104a, an indium gallium nitride 104b, and a second aluminum indium gallium nitride 104c. The first aluminum indium gallium nitride layer (Al _x In _y Ga _1-xy N , 0.05 ≦ x ≦ 0.2 , 0 ≦ y ≦ 0.15 ) 104a is designed to be partially doped and may have a thickness of 5 angstroms to 150 angstroms ( Preferably, the value is in the range of 60 Å to 120 Å, and the side directly contacting the active layer 103 is not doped, and the purpose is to block the diffusion of Mg atoms from the highly Mg-doped p-type indium gallium nitride to the active layer, and The film thickness is very thin, so that the hole carrier can be tunneled, and the luminous efficiency, forward voltage and aging characteristics of the nitride light-emitting diode assembly can be considered. In the first aluminum indium gallium nitride layer 104a, the doping position, thickness and number of Mg will affect the implementation effect of the present invention, and can be designed as follows: 1) The position of Mg doping may be the first aluminum indium nitride The middle or the second half of the gallium material layer is uniformly doped, and the doping concentration is greater than 5 × 10 ¹⁸ cm ^-3 , and the preferred thickness is less than 1/2 of the aluminum indium gallium nitride material layer. Aluminium indium gallium nitride film thickness of 1/3; 2) Mg doping position can also be Gaussian distribution, the surface doping concentration in contact with the active layer is the lowest (less than 1 × 10 ¹⁶ cm ^-3 ) Miscellaneous and graded to a high doping of 1 × 10 ¹⁹ cm ^-3 . Indium gallium nitride 104b is designed to be Mg-doped p-type indium gallium nitride (In _z Ga _1-z N, 0.2 ≦ z ≦ 0.3), which emphasizes Mg doping greater than 1 × 10 ¹⁹ cm ^-3 The purpose is to provide a high concentration of hole carrier by doping a high concentration of Mg atoms, thereby improving the luminous efficiency of the nitride light emitting diode assembly, which is 20% to 40% higher than the existing products. Brightness, and can reduce its own Barrier height to reduce its resistance, increase its conductivity, and reduce the forward voltage of the LED.

2 to FIG. 4 are schematic diagrams showing Mg doping concentration of a nitride light emitting diode device according to an embodiment of the present invention, and referring to FIGS. 2 to 4 It is more helpful to clearly illustrate the structure of the present invention.

Hereinafter, the present invention will be more specifically described by way of examples.

Example 1

 First, as Example 1, the process of the present invention, the conventional process (ie, the presence or absence of the locally doped p-type confinement structure of the process of the present invention) Two samples were prepared and their luminous output power, forward voltage and aging characteristics were evaluated. In the sample of the present embodiment, the doping position of 104a is distributed as shown in FIG.

In the present embodiment, the film thickness of each semiconductor layer was set as shown in Table 1.

Table 1 Floor Film thickness Å and structure of each layer of the process of the present invention Film thickness ( and structure of various layers of the traditional process Buffer layer 101 300 300 N-type layer 102 25000 25000 Active layer 103 GaN(140)/InGaN(25)
X10 cycle (last GaN layer) GaN(140)/InGaN(25)
X10 cycle (last GaN layer) P-type confinement structure 104 104a film thickness: 90; doping position: 104a middle middle section doping thickness: 30 doping amount: 1E + 19 ;
104b film thickness: 200; 104c film thickness: 500; (104 total film thickness 790) no P-type layer 105 2000 2000 P-type contact layer 106 100 100

 Figure 5, Figure 6, Figure 7, and Figure 8 show its evaluation results.

Embodiment 1 of the present invention as shown in FIG. A graph of the luminous output power of each sample, using the nitride light emitting diode module sample of the inventive process, has a higher luminous output power than the conventional nitride light emitting diode module sample at the same forward current.

The forward current of each sample of Example 1 of the present invention as shown in FIG. 6 - The forward voltage curve, using the nitride light emitting diode module sample of the process of the present invention, has a forward voltage lower than that of the conventional nitride light emitting diode module sample at the same forward current.

Embodiment 1 of the present invention as shown in FIG. The long-term aging light decay curve of each sample, the sample of the nitride light-emitting diode assembly using the process of the invention, has a light decay value superior to the conventional nitride light-emitting diode module sample under long-term aging.

Embodiment 1 of the present invention as shown in FIG. The long-term aging leakage current graph of each sample, using the nitride light-emitting diode module sample of the process of the present invention, has a leakage current value superior to the conventional nitride light-emitting diode module sample under long-term aging.

Example 2

 As Example 2, the process of the present invention, the conventional process (that is, the presence or absence of the partially doped p-type confinement structure of the process of the present invention), Two kinds of samples were evaluated for their luminous output power, forward voltage and aging characteristics.

In the present embodiment, the film thickness of each semiconductor layer was set as shown in Table 2.

Table 2 Floor Film thickness Å and structure of each layer of the process of the present invention Film thickness ( and structure of various layers of the traditional process Buffer layer 101 300 300 N-type layer 102 25000 25000 Active layer 103 GaN(140)/InGaN(25)
X10 cycle (last GaN layer) GaN(140)/InGaN(25)
X10 cycle (last GaN layer) P-type confinement structure 104 104a film thickness: 90; doping position: 104a doping thickness in the second half: 30 doping amount: 1E + 19;
104b film thickness: 200; 104c film thickness: 500; (104 total film thickness 790) no P-type layer 105 2000 2000 P-type contact layer 106 100 100

 Figure 9, Figure 10, Figure 11, and Figure 12 show its evaluation results.

A graph showing the luminous output power of each sample of Example 2 of the present invention as shown in FIG. The sample of the nitride light emitting diode assembly using the process of the present invention has a higher luminous output power than the conventional nitride light emitting diode module sample at the same forward current.

The forward current of each sample of Example 2 of the present invention as shown in FIG. The forward voltage curve, using the nitride light emitting diode module sample of the process of the present invention, has a forward voltage lower than that of the conventional nitride light emitting diode module sample at the same forward current.

Figure 11 Long-term aging light decay curve of each sample of the embodiment of the present invention, using the nitride light-emitting diode module sample of the process of the present invention, the light decay value is superior to the conventional nitride light-emitting diode component under long-term aging. sample.

Figure 12 The long-term aging leakage current curve of each sample of the embodiment of the present invention, using the nitride light-emitting diode module sample of the process of the present invention, the leakage current value is superior to the conventional process nitride light-emitting diode component under long-term aging. sample.

Example 3

 As Example 3, the process of the present invention, the conventional process (that is, the presence or absence of the partially doped p-type confinement structure of the process of the present invention), Two kinds of samples were evaluated for their luminous output power, forward voltage and aging characteristics.

In the present embodiment, the film thickness of each semiconductor layer was set as shown in Table 3.

table 3 Floor Film thickness Å and structure of each layer of the process of the present invention Film thickness ( and structure of various layers of the traditional process Buffer layer 101 300 300 N-type layer 102 25000 25000 Active layer 103 GaN(140)/InGaN(25)
X10 cycle (last GaN layer) GaN(140)/InGaN(25)
X10 cycle (last GaN layer) P-type confinement structure 104 104a film thickness: 90; doping position: 104a Gaussian distribution doping thickness: 90 doping amount: from low doping to high doping 1E + 19;
104b film thickness: 200; 104c film thickness: 500; (104 total film thickness 790) no P-type layer 105 2000 2000 P-type contact layer 106 100 100

 Figure 13, Figure 14, Figure 15, and Figure 16 show the results of its evaluation.

A graph of the luminous output power of each sample of the embodiment of the present invention as shown in FIG. The sample of the nitride light emitting diode assembly using the process of the present invention has a higher luminous output power than the conventional nitride light emitting diode module sample at the same forward current.

The forward current of each sample of the embodiment of the invention as shown in Figure 14 - A graph of forward voltage, using a nitride light emitting diode module sample of the process of the present invention, has a forward voltage lower than that of a conventional nitride light emitting diode module sample at the same forward current.

Figure 15 Long-term aging light decay curve of each sample of the embodiment of the present invention, using the nitride light-emitting diode module sample of the process of the present invention, the light decay value is superior to the conventional nitride light-emitting diode component under long-term aging. sample.

Figure 16 The long-term aging leakage current curve of each sample of the embodiment of the present invention, using the nitride light-emitting diode module sample of the process of the present invention, the leakage current value is superior to the conventional process nitride light-emitting diode component under long-term aging. sample.

The nitride light emitting diode assembly of the above embodiments can provide a high concentration of hole carriers in the above partially doped p type confinement structure 104. (Hole carrier), thereby improving the luminous efficiency of the nitride light emitting diode assembly and reducing its own barrier height (Barrier height ), thereby reducing the resistance value, increasing the conductivity thereof, and reducing the forward voltage of the nitride light emitting diode assembly; and the position, thickness, and concentration of the partially doped first aluminum nitride indium gallium layer doping are moderate, To block Mg Diffusion, Moreover, in order to increase the effective injection of holes, the luminous efficiency, forward voltage and aging characteristics of the nitride light-emitting diode assembly can be balanced, and therefore the present invention can be applied to applications requiring higher luminous efficiency and aging characteristics.

Claims (10)

a nitride light emitting diode comprising an n-type layer formed of a nitride semiconductor, an active layer and a p-type layer, and a p-type confinement structure further disposed between the p-type layer and the active layer, wherein the p-type confinement structure In the multilayer structure, the end portion in contact with the active layer is a layer of aluminum indium gallium nitride Al _x In _y Ga _1-xy N material, which is partially doped and in contact with the active layer. The surface is not doped. The nitride light emitting diode according to claim 1, wherein said p-type confinement structure has a thickness of 50 Å to 3000 Ai. The nitride light emitting diode according to claim 2, wherein the end portion of the aluminum indium gallium nitride material layer in contact with the active layer has a thickness of 5 Å to 150 Å. Ai. The nitride light emitting diode according to claim 1, wherein the aluminum indium gallium nitride material layer is partially doped with Mg. The nitride light emitting diode according to claim 4, wherein the end portion of the aluminum indium gallium nitride material layer in contact with the active layer is Mg The doped position is at the middle or the second half of the end aluminum nitride indium gallium material layer. The nitride light emitting diode according to claim 4, wherein the end portion of the aluminum indium gallium nitride material layer in contact with the active layer is Mg The doping is Gaussian, wherein the contact surface with the active layer is undoped. The nitride light emitting diode according to claim 4, wherein said Mg-indium gallium nitride material layer in contact with said active layer has said Mg The layer thickness of the doped aluminum indium gallium nitride material layer is less than 1/2 of the layer of the aluminum indium gallium nitride material. The nitride light emitting diode according to claim 4, wherein in the end portion of the aluminum indium gallium nitride material layer in contact with the active layer, the doping concentration of the local Mg is greater than 1 × 10 ¹⁷ cm ^-3 . The nitride light emitting diode according to claim 1, wherein said P The type confinement structure further includes: an indium gallium nitride and a second aluminum indium gallium nitride stack deposited on the end layer of aluminum indium gallium nitride material. The nitride light emitting diode according to claim 9, wherein the indium gallium nitride In _z Ga _1-z N film has a thickness of 10 Å to 800 Å and 0 < z < 0.4.

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