CN204102924U - A kind of blue-ray LED epitaxial structure with gradual change type DBR layer - Google Patents

Abstract

The utility model discloses a kind of blue-ray LED epitaxial structure with gradual change type DBR layer, relate to LED technology field.Its structure is followed successively by from the bottom to top: Sapphire Substrate; Low temperature GaN buffer; Gradual change type Bragg reflecting layer (DBR); N-shaped GaN, layer; Multiple quantum well light emitting layer; P-type AlGaN; P-type GaN contact layer.The utility model grows gradual change type DBR layer in blue-ray LED epitaxial structure, adopts gradual change type DBR can reflect the light of the downward directive substrate in active area, its light path is changed and penetrates to top.Gradual change type DBR can reflect low-angle incident light can reflect large angle incidence light again, and then improves the brightness of LED device.This epitaxial structure preparation technology is simple, easy to implement, easy to utilize.

Description

A kind of blue-ray LED epitaxial structure with gradual change type DBR layer

Technical field

The utility model relates to a kind of blue-ray LED epitaxial structure with gradual change type DBR layer.

Background technology

Semiconductor light-emitting-diode (light-emission diodes, LED) has the advantages such as volume is little, energy consumption is low, the life-span is long, environmental and durable because of it, has been widely used in the fields such as indicator light, display screen, backlight, illumination.Current indigo plant, green light LED mainly use GaN as basis material, GaN belongs to direct gap semiconductor, its ternary alloy three-partalloy InxGa1-xN (0 < x < 1) can band gap can from 0.7eV (InN) to 3.4eV (GaN) continuously adjustabe, the whole region of emission wavelength covering visible light and black light.Blue-light LED chip is used to coordinate yellow fluorescent powder can encapsulate out white light LED part.Current, energy savings and control global warmingization have become the subject under discussion paid attention to countries in the world, and the white light LED part of therefore power saving, environmental protection, safety, becomes the new light sources of 21 century.

The luminous efficiency of LED is commonly referred to as the external quantum efficiency of LED component, and external quantum efficiency is determined jointly by internal quantum efficiency and light extraction efficiency.Interior quantum is the electro-optical efficiency of device itself, depends on that crystal can be with, the base of defect, impurity, device crystalline substance composition and structure etc.At present, the internal quantum efficiency of LED component reaches 80% ~ 90%, and light extraction efficiency only has about 40% at present.In chip fabrication process, Sapphire Substrate directly contacts with packaging plastic, and the light sent downwards from active layer can sponge by direct packed glue, causes light extraction efficiency low.Therefore between Sapphire Substrate and active area, grow Bragg reflecting layer, the light light path sent downwards is changed, emit from chip front side from active layer.DBR is the layer structure of two kinds of refractive index different materials cycle alternating growths, grows between active layer and substrate, the light of directive substrate can be reflected back surface or side, can reduce the absorption to light, improves light extraction efficiency.Dbr structure can directly utilize MOCVD device to grow, and again need not process process, simplifies the manufacture craft of device.

Utility model content

The utility model discloses a kind of blue-ray LED epitaxial structure with gradual change type dbr structure, described structure is followed successively by from the bottom to top: substrate; Low temperature GaN buffer; Distributed Bragg reflecting layer (DBR); N-type GaN layer; Multiple quantum well light emitting layer; P-type AlGaN; P-type GaN contact layer; Described distributed Bragg reflecting layer is gradual change type Bragg reflector (DBR) structure.

The utility model grows gradual change type DBR layer in blue-ray LED epitaxial structure, can improve epitaxial wafer light extraction efficiency.Adopt gradual change type DBR can reflect the light of the downward directive substrate in active area, its light path is changed and penetrates to top.Gradual change type DBR can reflect low-angle incident light can reflect large angle incidence light again, and then improves the brightness of LED device.This epitaxial structure preparation technology is simple, easy to implement, easy to utilize.

Accompanying drawing explanation

Describe exemplary embodiment of the present utility model in more detail by referring to accompanying drawing, above and other aspect of the present utility model and advantage will become and more be readily clear of, in the accompanying drawings:

Fig. 1 is the vertical section structure schematic diagram of a kind of blue-ray LED epitaxial structure with gradual change type DBR layer of the present utility model.

Embodiment

Hereinafter, more fully the utility model is described now with reference to accompanying drawing, various embodiment shown in the drawings.But the utility model can be implemented in many different forms, and should not be interpreted as being confined to embodiment set forth herein.On the contrary, provide these embodiments to make the disclosure will be thoroughly with completely, and scope of the present utility model is conveyed to those skilled in the art fully.

Hereinafter, with reference to the accompanying drawings exemplary embodiment of the present utility model is described in more detail.

With reference to accompanying drawing 1, a kind of blue-ray LED epitaxial structure with gradual change type dbr structure, is characterized in that: described structure is followed successively by from the bottom to top: substrate; Low temperature GaN buffer; Distributed Bragg reflecting layer (DBR); N-type GaN layer; Multiple quantum well light emitting layer; P-type AlGaN; P-type GaN contact layer; Described distributed Bragg reflecting layer is gradual change type Bragg reflector (DBR) structure.

Described gradual change type dbr structure can adopt two kinds of spaced cycle growth of different materials to form, and periodicity is 2 ~ 10.

Employing mocvd method grows, and gradual change type dbr structure, by gradual manner, is made up of AlN/GaN.

The m layer AlN material of gradual change type DBR and the thickness of m layer GaN material are respectively:

$d_m=\frac{{\mathrm{\&lambda;}}_m}{4n_1},d_m=\frac{{\mathrm{\&lambda;}}_m}{4n_2}---\left(1\right);$

λ _m=λ ₀(1+t) or λ _m=λ ₀(1+t ²) (2);

In formula (1)-(2): λ ₀for the centre wavelength of device active region luminescence, n ₁and n ₂be respectively the refractive index of AlN material and GaN material, t is positive number, and t is according to λ _mdifference and get different values, m is positive integer;

The foregoing is only embodiment of the present utility model, be not limited to the utility model.The utility model can have various suitable change and change.All do within spirit of the present utility model and principle any amendment, equivalent replacement, improvement etc., all should be included within protection range of the present utility model.

Claims (3)

1. with a blue-ray LED epitaxial structure for gradual change type dbr structure, it is characterized in that: described structure is followed successively by from the bottom to top: substrate, low temperature GaN buffer, distributed Bragg reflecting layer, n-type GaN layer, multiple quantum well light emitting layer, p-type AlGaN, p-type GaN contact layer; Described distributed Bragg reflecting layer is gradual change type Bragg reflector structure.

2. a kind of blue-ray LED epitaxial structure with gradual change type dbr structure according to claim 1, is characterized in that: described in fade to linear gradient or parabolic grades, the m layer AlN material of gradual change type DBR and the thickness of m layer GaN material are respectively:

λ _m=λ ₀(1+t) or λ _m=λ ₀(1+t ²) (2);

In formula (1)-(2): λ ₀for the centre wavelength of device active region luminescence, n ₁and n ₂be respectively the refractive index of AlN material and GaN material, t is positive number, and t is according to λ _mdifference and get different values, m is positive integer.

3. LED epitaxial structure according to claim 1, is characterized in that: described gradual change type DBR epitaxial structure, periodicity is 2 ~ 10.