CN214043696U - Epitaxial layer for improving luminous efficiency of GaN-based green light LED - Google Patents

Abstract

The utility model discloses an epitaxial layer for improving the luminous efficiency of a GaN-based green light LED, which comprises a substrate, an AlN buffer layer, a U-shaped GaN layer, an N-shaped GaN layer, a multi-quantum well, an electron barrier layer, a P-shaped GaN layer and a metal contact layer which are sequentially superposed on the substrate; the multiple quantum well comprises a periodic structure formed by alternately stacking a plurality of pairs of GaN layers and InGaN layers, and an InGaN layerThe quantum barrier layer is arranged on the periodic structure and comprises an unintentional doped GaN layer, a superlattice layer and a P-type InGaN layer arranged on the superlattice layer; the superlattice layer comprises pairs of alternately stacked unintentionally doped In_xGa_1‑xN and unintentionally doped Al_yGa_1‑yAnd N is added. The utility model provides a quantum barrier layer in the multiple quantum well can effectively alleviate near LQB's energy band crooked, reduces the well barrier layer polarization effect, improves gaN base green glow LED luminous efficacy, but wide application in semiconductor lighting technology field.

Description

Epitaxial layer for improving luminous efficiency of GaN-based green light LED

Technical Field

The utility model belongs to the technical field of the semiconductor lighting technology and specifically relates to a promote epitaxial layer of gaN base green glow LED luminous efficacy.

Background

An LED (Light Emitting Diode) is a semiconductor-fixed Light Emitting device, and can directly convert electrical energy into optical energy by using a PN junction, and has the advantages of energy saving, environmental friendliness, small size, long service life, and the like in the field of illumination. The luminous efficiency of the LED is one of the most important indexes for measuring the quality of the LED device, and improving the luminous characteristics of the LED has become a major factor for improving the luminous efficiency.

In the prior art, a GaN-based green light LED quantum well barrier layer structure has a strong polarization effect, and causes energy band bending and electron overflow of an Electron Barrier Layer (EBL), so that the problems of low internal quantum Efficiency, such as Efficiency reduction (Efficiency Droop), injection Efficiency reduction of a hole with high effective mass and low mobility entering an active region after crossing the EBL, and the like, are caused, and the improvement of the LED luminous Efficiency is restricted. Therefore, the quantum barrier layer design needs to be optimized, so that the purposes of reducing the polarization effect caused by lattice mismatch of the well barrier layer and improving the efficiency of injecting holes into the quantum well are achieved, and the radiation recombination luminous efficiency of the quantum well is improved.

Disclosure of Invention

The utility model aims at providing a promote epitaxial layer of gaN base green glow LED luminous efficacy, it is strong to solve current well barrier layer polarization effect, problem that luminous efficiency is low.

The utility model provides a technical scheme that its technical problem adopted is: an epitaxial layer for improving the luminous efficiency of a GaN-based green light LED comprises a substrate, and an AlN buffer layer, a U-shaped GaN layer, an N-shaped GaN layer, a multi-quantum well, an electron blocking layer, a P-shaped GaN layer and a metal contact layer which are sequentially stacked on the substrate; the method is characterized in that: the multiple quantum well comprises a periodic structure formed by alternately stacking a plurality of pairs of GaN layers and InGaN layers and a quantum barrier layer arranged on the periodic structure, wherein the quantum barrier layer comprises an unintentionally doped GaN layer, a superlattice layer and a P-type InGaN layer arranged on the superlattice layer; the superlattice layer comprises pairs of alternately stacked unintentionally doped In_xGa_1-xN and unintentionally doped Al_yGa_1-yN。

Furthermore, the substrate is a patterned substrate, the material is one of sapphire, silicon carbide, indium phosphide, gallium nitride and gallium arsenide, the shape of the pattern is a Mongolian yurt shape, the period is 1-3 μm, the height is 0.5-2.4 μm, and the bottom width is 0.5-3 μm.

Preferably, the unintentionally doped In_xGa_1-xN and unintentionally doped Al_yGa_1-yThe number of the periodic repetitions of N is 2 to 8, the total thickness is 1nm to 2nm, and the thickness of the unintentionally doped GaN layer is 1 to 5 nm.

The utility model has the advantages that: the utility model provides a quantum barrier layer In the multiple quantum well grows the better unintended doping GaN layer of one deck crystal quality earlier and is regarded as the transition layer of protection quantum well, and the unintended doped In of secondary growth_xGa_{1- x}N and unintentionally doped Al_yGa_1-yN has a stress compensation effect, so that the tensile stress of the quantum well region and the compressive stress of the electron barrier layer can be mutually offset in the superlattice layer, and the energy band bending near LQB can be effectively reduced. And finally, growing a C-doped P-type InGaN layer, wherein on one hand, the C doping can perform acceptor compensation to reduce a donor state and reduce the concentration of GaN background carriers, meanwhile, the delta doping of the C can generate high-concentration two-dimensional holes and high hole mobility, and the generated holes do not need to cross a higher electron blocking layer of a band gap, so that the efficiency of injecting the holes into an active region is improved, and the radiation efficiency of a green LED is improvedEmitting composite light with high luminous efficiency. On the other hand, the diffusion coefficient of C is lower than that of Mg, so that the probability of C impurities diffusing to the quantum well region to form a non-radiative recombination center is greatly reduced; the potential barrier height of InGaN is lower than that of the electron barrier layer, the limiting capability of the electron barrier layer on electrons is relatively improved, the efficiency reduction caused by electron overflow is reduced, the luminous efficiency of the green light LED can be effectively improved by using the nano-micron grade Mongolian yurt graphical substrate, and the dislocation density and reverse electric leakage of epitaxy are reduced.

The present invention will be described in more detail with reference to the accompanying drawings and examples.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic structural diagram of a multiple quantum well according to the present invention.

Fig. 3 is a schematic structural view of the middle quantum barrier layer of the present invention.

Fig. 4 is a schematic structural diagram of the substrate according to the present invention.

Detailed Description

In an embodiment, as shown in fig. 1 to 4, an epitaxial layer for improving the light emitting efficiency of a GaN-based green light LED includes a substrate 100, the substrate 100 is a patterned substrate, preferably sapphire, or silicon, silicon carbide, indium phosphide, gallium nitride, gallium arsenide, and the like, and the pattern 101 is in a shape of a yurt, with a period of 1 to 3 μm, a height of 0.5 to 2.4 μm, and a bottom width of 0.5 to 3 μm. The pattern period refers to the distance between the center points of two adjacent patterns. An AlN buffer layer 200, a U-type GaN layer 300, an N-type GaN layer 400, a Multiple Quantum Well (MQW) 500, an electron blocking layer 600, a P-type GaN layer 700, and a metal contact layer 800, which are sequentially stacked on a substrate 100.

The N-type GaN layer 400 is doped with impurity Si at a doping concentration of 2x10¹⁷cm³ ~4.5x10²⁰cm³ (ii) a The P-type GaN layer 700 is doped with Mg impurity with a doping concentration of 1E +18 atom/cm³~1E+21 atom/cm³(ii) a The metal contact layer 800 is doped with an impurity C, wherein the doping concentration of C is 5E17atom/cm³~1E19atom/cm³。

Said multiple quantum well 500 includes a periodic structure 510 in which pairs of GaN layers 511 and InGaN layers 512 are alternately stacked and quantum barrier Layers (LQB) 520 disposed on the periodic structure 510, as shown in fig. 2. The quantum barrier layer 520 comprises an unintentionally doped GaN layer 521, a superlattice layer 522 and a P-type InGaN layer 523 arranged on the superlattice layer 522; the superlattice layer 522 includes pairs of alternately stacked pairs of unintentionally doped In_xGa_1-xN5220 and unintentionally doped Al_yGa_1-yN5221 as shown in fig. 3. Said In_XGa_1-XN layer and Al_yGa_1-yN layer undoped, In_xGa_1-xIn the N alloy, the indium component is more than or equal to 0 and less than or equal to 0.2, and the x is more than or equal to 0_yGa_1-yY in the N alloy is more than or equal to 0 and less than or equal to 0.05. The unintentionally doped In_xGa_1-xN and unintentionally doped Al_yGa_1-yThe number of the periodic repetitions of N is 2 to 8, the total thickness is 1nm to 2nm, and the thickness of the unintentionally doped GaN layer is 1 to 5 nm.

The invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above-described manner. Various insubstantial improvements are made by adopting the method conception and the technical proposal of the utility model; or without improvement, the above conception and technical solution of the present invention can be directly applied to other occasions, all within the protection scope of the present invention.

Claims (3)

1. An epitaxial layer for improving the luminous efficiency of a GaN-based green light LED comprises a substrate, and an AlN buffer layer, a U-shaped GaN layer, an N-shaped GaN layer, a multi-quantum well, an electron blocking layer, a P-shaped GaN layer and a metal contact layer which are sequentially stacked on the substrate; the method is characterized in that: the multiple quantum well comprises a periodic structure formed by alternately stacking a plurality of pairs of GaN layers and InGaN layers and a quantum barrier layer arranged on the periodic structure, wherein the quantum barrier layer comprises an unintentionally doped GaN layer, a superlattice layer and a P-type InGaN layer arranged on the superlattice layer; the superlattice layer comprises pairs of alternately stacked unintentionally doped In_xGa_1-xN and unintentionally doped Al_yGa_1-yN。

2. The epitaxial layer of claim 1 for enhancing the luminous efficiency of a GaN-based green LED, wherein: the substrate is a patterned substrate, the material is one of sapphire, silicon carbide, indium phosphide, gallium nitride and gallium arsenide, the shape of the pattern is a Mongolian yurt shape, the period is 1-3 mu m, the height is 0.5-2.4 mu m, and the bottom width is 0.5-3 mu m.

3. The epitaxial layer of claim 1 for enhancing the luminous efficiency of a GaN-based green LED, wherein: the unintentionally doped In_xGa_1-xN and unintentionally doped Al_yGa_1-yThe number of the periodic repetitions of N is 2 to 8, the total thickness is 1nm to 2nm, and the thickness of the unintentionally doped GaN layer is 1 to 5 nm.

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