CN103400910A - White light LED (Light-emitting Diode) extension structure and manufacturing method thereof - Google Patents

Abstract

The invention provides a white light LED (Light-emitting Diode) extension structure and a manufacturing method thereof. GaN-based LED extension structure growth is carried out by adopting YAG crystalline ceramics doped with rare earth element or single crystal as a substrate. The extension structure comprises a low-temperature AlN buffer layer, a low-temperature GaN buffer layer, a GaN buffer layer, an n-shaped GaN layer, a AlGaN barrier layer, a InGaN/GaN multiple quantum wells luminescent layer, a AlGaN barrier layer, a P-shaped GaN layer and a highly doped p-shaped GaN electrode contact layer from bottom to top. The LED extension layer structure takes fluorescent materials as the substrate, and an LED chip prepared by the extension structure can realize direct white light emission, so that a preparation process of a white light LED light source is simplified, and the production cost is reduced.

Description

A kind of white light LEDs epitaxial structure and manufacture method thereof

Technical field

The present invention relates to the preparation method of a kind of LED chip of field of photoelectric technology, relate in particular to a kind of preparation method of white light LEDs epitaxial wafer.

Background technology

LED is as a kind of new type light source, owing to having energy-saving and environmental protection, the life-span is long, toggle speed is fast, can control luminescent spectrum and forbid making the unrivaled advantage of the more high conventional light source of colorfulness obtain unprecedented development with the size of width.

At present, the white light LEDs purposes of in illumination, drenching with rain is more and more extensive.Now the generating white light mode of white light LEDs is all to smear YAG fluorescent material on the LED chip of blue light-emitting with city, wherein is no lack of wave and runs into excitated fluorescent powder after fluorescent material, makes the fluorescent material Yellow light-emitting low temperature, and gold-tinted namely sends white light with the residue blue light.

But for common blue-light LED chip, its photoelectric conversion efficiency is generally lower than 30%, even present best LED chip, its photoelectric conversion efficiency can be higher than 50% yet.Therefore LED will supervene a large amount of heat when luminous.General around the chip of lighting, temperature can arrive 150 degrees centigrade to 200 degrees centigrade.Such temperature will cause the decrease in efficiency 20-30% of fluorescent material, thereby produce the colour temperature of light source and the skew of chromaticity coordinates.Light efficiency and the stability of LED light source have also been affected simultaneously.

Summary of the invention

The present invention is intended to solve the foregoing problems of prior art, the invention provides a kind of fluorescent material that need not to use, a kind of GaN base white light LEDs epitaxial wafer of growing on the YAG of novel rare-earth element doping pottery or single crystalline substrate, also provide the growth technique of this epitaxial wafer simultaneously.

For achieving the above object, a kind of GaN base white light LEDs epitaxial wafer, its structure is followed successively by substrate, low temperature AI N resilient coating, low temperature GaN resilient coating, GaN resilient coating, N-shaped GaN layer, AlGaN barrier layer, InGaN/GaN multiple quantum well light emitting layer, AlGaN barrier layer, P type GaN layer and highly doped p type GaN contact electrode layer from bottom to top, and its substrate adopts rare earth doped YAG pottery or monocrystalline.

Described rare earth doped YAG pottery or monocrystalline rare earth elements are selected from Ce, Eu, Er, Nd, Tb, Sm, Tm, Dy or Yb, and doping is 0.005 to 25wt.%.

Described rare earth element is optional wherein a kind of or several arbitrarily.

Described rare earth doped YAG pottery or YAG pottery or the meticulous polishing of single-crystal surface process of single crystalline substrate, its surface roughness reaches 0.1-0.3nm.

A kind of GaN base white light LEDs epitaxial wafer of growing on rare earth doped YAG pottery or single crystalline substrate, the metallo-organic compound chemical gaseous phase depositing process is adopted in its growth, and growth technique is for carrying out successively following steps:

(1) at first with YAG pottery or single crystalline substrate at 800 ℃-1400 ℃, carry out a kind of jade 5-20 minute of high-temperature cleaning place in hydrogen atmosphere;

(2) temperature drops to 500 ℃-700 ℃, growth 15-60nm thickness low temperature AI N resilient coating;

(3) temperature remains on 500 ℃-700 ℃, growth 50nm-300nm thickness low temperature GaN resilient coating;

(4) temperature is increased to 900 ℃-1200 ℃, growth 2-4um thickness high temperature GaN resilient coating;

(5) temperature is increased to 900 ℃-1200 ℃, the N-shaped GaN layer of growth 1um-3um, and it is 1 * 10 that Si mixes solubility ¹⁷cm ^-3-3 * 10 ²⁰cm ^-3

(6) temperature is down to 650 ℃-850 ℃, the InGaN/GaN multiple quantum well layer of 1-30 the circulation of growing;

(7) temperature is 800 ℃-1150 ℃, the p-type GaN layer of growth 100nm-800nm, and doping solubility is 1 * 10 ¹⁷cm ^-3-3 * 10 ²⁰cm ^-3

(8) temperature is 800 ℃-1150 ℃, the highly doped p-type GaN contact electrode layer of growth 5nm-50nm, and it is 1 * 10 that Mg mixes solubility ¹⁸cm ^-3-5 * 10 ²⁰cm ^-3

The present invention, by utilizing rare earth doped YAG pottery or monocrystalline to be substrate, at its superficial growth GaN base blue-ray LED epitaxial structure, thereby makes blue-light excited YAG pottery or single crystalline substrate be mixed into white light.Thereby realized the growth of GaN base white light LEDs epitaxial wafer, avoided the use of fluorescent material in conventional white light LED, thereby effectively avoided because the fluorescent material quantum efficiency that high temperature causes descends, the colour temperature of light source the chromaticity coordinates drift.Simultaneously also simplify the white light LEDs production routine, greatly reduced the white light LEDs production cost.

Description of drawings

A kind of white light LEDs epitaxial structure of Fig. 1 schematic diagram.

Embodiment

Example 1: with the Ce of 0.005wt.% ₂O ₃Powder mixes in the YAG powder, by wet ball grinding, fully mixes, the dry rear fluorescence ceramics powder material that obtains.Be idiosome with the fluorescence ceramics powder material by cold isostatic compaction.Idiosome is put into the vacuum high-temperature sintering stove, and sintering temperature is 1450 ℃, sintering time 10 hours.Transparent ceramic sample thickness after attenuate and surface fine polishing that sintering is completed is 600 μ m, and surface roughness is 3nm.Be that substrate is put into metal-organic chemical vapor deposition equipment with this Ce:YAG transparent ceramic material, carry out high-temperature cleaning and processed 20 minutes in 800 ℃ of hydrogen atmospheres, temperature drops to 500 ℃, growth 15nm thickness low temperature AI N resilient coating; Continued growth 300nm thickness low temperature GaN resilient coating; Temperature is increased to 900 ℃, growth 2 μ m thickness high temperature GaN resilient coatings; Keep 900 ℃, the N-shaped GaN layer of growth 3um, it is 1 * 10 that Si mixes solubility ¹⁷cm ^-3Cool the temperature to again 650 ℃, the InGaN/GaN multiple quantum well layer of 30 circulations of growth; Temperature is risen to 800 ℃ again, the p-type GaN layer of growth 100nm, doping solubility is 3 * 10 ²⁰cm ^-3Keep 800 ℃ of temperature, the highly doped p-type GaN contact electrode layer of growth 50nm, it is 5 * 10 that Mg mixes solubility ²⁰cm ^-3, finally depositing device is down to room temperature.

Example 2 is with the Ce of 0.3wt.% ₂O ₃Powder mixes in the YAG powder, by wet ball grinding, fully mixes, the dry rear fluorescence ceramics powder material that obtains.Be idiosome with the fluorescence ceramics powder material by cold isostatic compaction.Idiosome is put into the vacuum high-temperature sintering stove, and sintering temperature is 1850 ℃, sintering time 15 hours.Transparent ceramic sample thickness after attenuate and surface fine polishing that sintering is completed is 450 μ m, and surface roughness is 2nm.Be that substrate is put into metal-organic chemical vapor deposition equipment with this Ce:YAG ceramic material, carry out high-temperature cleaning and processed 20 minutes in 1400 ℃ of hydrogen atmospheres, temperature drops to 700 ℃, growth 60nm thickness low temperature AI N resilient coating; Continued growth 50nm thickness low temperature GaN resilient coating; Temperature is increased to 1200 ℃, growth 4 μ m thickness high temperature GaN resilient coatings; Keep 1200 ℃, the N-shaped GaN layer of growth 1um, it is 3 * 10 that Si mixes solubility ²⁰cm ^-3Cool the temperature to again 850 ℃, the InGaN/GaN multiple quantum well layer of 25 circulations of growth; Temperature is risen to 1150 ℃ again, the p-type GaN layer of growth 800nm, doping solubility is 1 * 10 ¹⁷cm ^-3Keep 1150 ℃ of temperature, the highly doped p-type GaN contact electrode layer of growth 5nm, it is 5 * 10 that Mg mixes solubility ²⁰cm ^-3, finally depositing device is down to room temperature.

Example 3 is with the Ce of 1.2wt.% ₂O ₃The Gd of powder and 25wt.% ₂O ₃Mix in the YAG powder, by wet ball grinding, fully mix, the dry rear fluorescence ceramics powder material that obtains.Be idiosome with the fluorescence ceramics powder material by cold isostatic compaction.Idiosome is put into the vacuum high-temperature sintering stove, and sintering temperature is 1830 ℃, sintering time 12 hours.Transparent ceramic sample thickness after attenuate and surface fine polishing that sintering is completed is 350 μ m, and surface roughness is 1nm.Be that substrate is put into metal-organic chemical vapor deposition equipment with this Ce:YAG ceramic material, carry out high-temperature cleaning and processed 15 minutes in 1300 ℃ of hydrogen atmospheres, temperature drops to 500 ℃, growth 60nm thickness low temperature AI N resilient coating; Temperature rises to 700 ℃, growth 50nm thickness low temperature GaN resilient coating; Temperature is increased to 1100 ℃, growth 4 μ m thickness high temperature GaN resilient coatings; Temperature rises to 1200 ℃, the N-shaped GaN layer of growth 1um, and it is 1.5 * 10 that Si mixes solubility ¹⁹cm ^-3Cool the temperature to again 850 ℃, the InGaN/GaN multiple quantum well layer of 30 circulations of growth; Temperature is risen to 1050 ℃ again, the p-type GaN layer of growth 500nm, doping solubility is 2 * 10 ¹⁷cm ^-3Temperature rises to 1180 ℃, the highly doped p-type GaN contact electrode layer of growth 15nm, and it is 3 * 10 that Mg mixes solubility ¹⁹cm ^-3, finally depositing device is down to room temperature.

Example 4 is with the Ce of 0.005wt.% ₂O ₃Powder mixes in the YAG powder, by wet ball grinding, fully mixes, the dry rear powder material that obtains fluorescent crystal.Be idiosome with the fluorescent powder raw material by cold moudling.Idiosome is put into the vacuum high-temperature monocrystal growing furnace, be warmed up to the powder fusing, utilize the YAG seed crystal to carry out pulling growth.Crystal-cut after growth is become epitaxial wafer, and thickness is 600 μ m after attenuate and surface fine polishing, and surface roughness is 3nm.Be that substrate is put into metal-organic chemical vapor deposition equipment with this Ce:YAG monocrystal material, carry out high-temperature cleaning and processed 20 minutes in 800 ℃ of hydrogen atmospheres, temperature drops to 500 ℃, growth 15nm thickness low temperature AI N resilient coating; Continued growth 300nm thickness low temperature GaN resilient coating; Temperature is increased to 900 ℃, growth 2 μ m thickness high temperature GaN resilient coatings; Keep 900 ℃, the N-shaped GaN layer of growth 3um, it is 1 * 10 that Si mixes solubility ¹⁷cm ^-3Cool the temperature to again 650 ℃, the InGaN/GaN multiple quantum well layer of 30 circulations of growth; Temperature is risen to 800 ℃ again, the p-type GaN layer of growth 100nm, doping solubility is 3 * 10 ²⁰cm ^-3Keep 800 ℃ of temperature, the highly doped p-type GaN contact electrode layer of growth 50nm, it is 5 * 10 that Mg mixes solubility ²⁰cm ^-3, finally depositing device is down to room temperature.

Foregoing is four specific embodiments of the present invention, and be not limitation of the present invention, any trickle modification, equivalent variations and modification that every foundation technical spirit of the present invention is done top embodiment, all still belong to technology contents of the present invention and scope.

Claims (5)

1. GaN base white light LEDs epitaxial wafer, its structure is followed successively by substrate, low temperature AI N resilient coating, low temperature GaN resilient coating, GaN resilient coating, N-shaped GaN layer, AlGaN barrier layer, InGaN/GaN multiple quantum well light emitting layer, AlGaN barrier layer, P type GaN layer and highly doped p-type GaN contact electrode layer from bottom to top, it is characterized in that: its substrate adopts rare earth doped Y ₃Al ₅O ₁₂(YAG) pottery or monocrystalline.

2. a kind of GaN base white light LEDs epitaxial wafer according to claim 1, it is characterized in that, described rare earth doped YAG pottery or monocrystalline rare earth elements are selected from Ce, Eu, Er, Nd, Tb, Sm, Tm, Dy or Yb, and doping is that 0.005wt% is to 25wt.%.

3. according to claim 1 with 2 described a kind of GaN base white light LEDs epitaxial wafers, is characterized in that, described rare earth element is optional wherein a kind of or several arbitrarily.

4. a kind of GaN base white light LEDs epitaxial wafer according to claim 1, is characterized in that, as YAG pottery or the meticulous polishing of single-crystal surface process of substrate, its surface roughness reaches 0.1-0.3nm.

5. a kind of GaN base white light LEDs epitaxial wafer according to claim 1, is characterized in that, adopts metallo-organic compound chemical meteorology deposition method, carries out successively following steps:

(1) at first with YAG pottery or single crystalline substrate at 800 ℃-1400 ℃, carry out high-temperature cleaning in hydrogen atmosphere and process 5-20 minute;

(2) temperature drops to 500 ℃-700 ℃, growth 15-60nm thickness low temperature AI N resilient coating;

(3) temperature remains on 500 ℃-700 ℃, growth 50nm-300nm thickness low temperature GaN resilient coating;

(4) temperature is increased to 900 ℃-1200 ℃, growth 2-4um thickness high temperature GaN resilient coating;

(5) temperature is increased to 900 ℃-1200 ℃, the N-shaped GaN layer of growth 1um-3um, and it is 1 * 10 that Si mixes solubility ¹⁷cm ^-3-3 * 10 ²⁰cm ^-3

(6) temperature is down to 650 ℃-850 ℃, the InGaN/GaN multiple quantum well layer of 1-30 the circulation of growing;

(7) temperature is 800 ℃-1150 ℃, the p-type GaN layer of growth 100nm-800nm, and doping solubility is 1 * 10 ¹⁷cm ^-3-3 * 10 ²⁰cm ^-3

(8) temperature is 800 ℃-1150 ℃, the highly doped p-type GaN contact electrode layer of growth 5nm-50nm, and it is 1 * 10 that Mg mixes solubility ¹⁸cm ^-3-5 * 10 ²⁰cm ^-3

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