CN101359710B - Manufacturing method of green light LED - Google Patents

Abstract

The invention relates to a method for fabricating a green LED, which is mainly characterized in that through the introduction of an insert layer into an epitaxial growth InGaN/GaN quanta well, V type defects between the InGaN and the GaN is reduced and In precipitation is reduced; thus, the green LED with high brightness and strong antistatic ability can be obtained. With the introduction of the insert layer, the brightness of a 300micronx300micron green LED chip at 520nm under 20mA is improved from 100mcd to 250mcd and the antistatic ability of the chip is increased from HBM 500V (human-body model) to HBM 4000V.

Description

A kind of manufacture method of green light LED

Technical field

The present invention relates to organic metal vapor deposition (MOCVD) epitaxial growth method of a kind of gallium nitride (GaN), especially relate to a kind of manufacture method of green light LED for the III-V group nitride material of base.

Background technology

GaN base III-V group-III nitride is the semiconductor material with wide forbidden band of important direct band gap.The GaN sill has excellent material mechanical and chemical property, excellent photoelectric property, under the room temperature its bandgap range from 0.7eV (InN) to 6.2eV (AlN), emission wavelength has been contained far infrared, infrared, visible light, ultraviolet light and deep ultraviolet, and the GaN sill is in field of optoelectronic devices such as blue light, green glow, purple light and the white light-emitting diodes background that is widely used.

The external quantum efficiency of GaN base blue-ray LED obtained great raising in recent years, reach 45% (referring to: Appl.Phys.Lett 89,071109), but the external quantum efficiency of green light LED with respect to the basic blue-ray LED of GaN much lower (referring to: Appl.Phys.Lett 86,101903 etc.), green light LED needs high-quality high In ingredient InxGal-xN/GaN quantum well (x 〉=15%), yet because being separated of In takes place in the InGaN material of high In ingredient easily, and the interface of InxGaN/GaN Multiple Quantum Well is easy to generate a large amount of V-type defectives, above-mentioned is that the green light LED external quantum efficiency is low, the main cause of antistatic effect difference.

Given this, be necessary to provide a kind of new process to overcome above-mentioned shortcoming.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of manufacture method of green light LED, by the method minimizing InGaN of introducing one deck insert layer in epitaxial growth InGaN/GaN quantum well and the V-type defective between GaN, and reduce separating out of In component, thereby the acquisition high brightness, the green light LED that antistatic effect is strong.

In order to solve the problems of the technologies described above, the present invention adopts following technical scheme: a kind of manufacture method of green light LED, it adopts the MOCVD method, utilizes high-purity N H3 to do the N source, and trimethyl gallium or triethyl-gallium are done the gallium source, trimethyl indium is done the indium source, trimethyl aluminium is done the aluminium source, and silane is as n type dopant, and two luxuriant magnesium are as p type dopant, it is characterized in that this method may further comprise the steps:

Step 1 is handled the Sapphire Substrate surface with H2 under high temperature in the MOCVD reative cell, the growing low temperature nucleating layer of lowering the temperature is then followed growing GaN resilient coating at high temperature, and this GaN resilient coating comprises non-Doped GaN layer and mixes the n type GaN layer of Si;

Step 2 is reduced to temperature between 650～750 ℃, and carrier gas switches to N2, and In grows on the GaN resilient coating _xGa _1-xThe N/GaN quantum well, 0.15≤x≤0.35 wherein, described In _xGa _1-xThe N/GaN quantum well comprises InGaN trap layer, and insert layer and GaN build layer, and wherein the molar flow of TEGa is 0.1 * 10 ^-5Moles/min to 1.5 * 10 ^-5Moles/min, the molar flow of TMIn are 5 * 10 ^-5Moles/min to 10 * 10 ^-5Between the moles/min or the molar flow of TMA1 be 0～1.0 * 10 ^-5The mole moles/min, the flow of NH3 is 12 liters/minute.

Step 3 is at In _xGa _1-xGenerate p type AlGaN electronic barrier layer and p type GaN layer on the N/GaN quantum well layer.

As one of a preferred embodiment of the present invention, this insert layer is In _yGa _1-yN, the thickness 0.1～5nm of wherein x＜y≤1, and this layer.

As one of a preferred embodiment of the present invention, this insert layer is Al _zGa _1-zN, the thickness of wherein 0＜z≤1, and this layer are 0.1～5nm.

As one of a preferred embodiment of the present invention, this insert layer is Al _aIn _bGa _1-a-bN, wherein 0＜a＜1,0＜b＜1 and a, the value of b need satisfy the potential barrier that its potential barrier is higher than GaN, and the thickness of this layer is 0.1～5nm.

As one of a preferred embodiment of the present invention, this insert layer is In _cAl _1-cN, x＜c≤1 wherein, the thickness of this layer is 0.1～5nm.

As one of a preferred embodiment of the present invention, this InGaN/GaN Multiple Quantum Well that comprises insert layer is applicable to but is not limited to green light LED, and the number of quantum well is 1～20.

The present invention mainly passes through to introduce the method minimizing InGaN of one deck insert layer and the V-type defective between GaN in epitaxial growth InGaN/GaN quantum well, and reduces separating out of In component, thereby the acquisition high brightness, the green light LED that antistatic effect is strong.After introducing insert layer, the brightness under the 20mA of the green light LED chip of 300 microns * 300 microns 520nm is increased to 250mcd by 100mcd, and the antistatic effect of chip is increased to Human Body Model 4000V by Human Body Model 500V.

Description of drawings

Fig. 1 is the structural representation of green light LED of the present invention;

Wherein, 1. Sapphire Substrate; 2.GaN nucleating layer; 3. non-Doped GaN layer; 4.n type GaN layer; 5.InGaN/GaN multiple quantum well active layer; Wherein, 5a is an InGaN trap layer, and 5b is middle insert layer, and 5c is that GaN builds layer; 6.p type AlGaN carrier barrier layer; 7.p type GaN layer.

Fig. 2 is the luminous power and the current curve diagram of green light LED of the present invention.

Wherein, curve 1 is the luminous power and the current curve diagram of the green light LED of the present invention's volume minor structure of containing insert layer; Curve 2 is luminous power and current curve diagrams of green light LED of the multi-quantum pit structure of no insert layer.

Embodiment

Further specify concrete implementation step of the present invention below in conjunction with accompanying drawing:

Embodiment one

Utilize the green light LED of MOCVD equipment epitaxial growth high brightness, used substrate is the sapphire of (001) face.As shown in Figure 1, at first in the MOCVD reative cell Sapphire Substrate 1 is heated to 1200 ℃, handles 5min under H2, temperature is reduced to 500～600 ℃ of growing GaN nucleating layers 2 then, the about 30nm of thickness; Temperature rises to 1160 ℃ then, H2 does carrier gas, with the GaN resilient coating of 3.0 microns/hour growth rate epitaxial growth 4 micron thickness, comprising the involuntary Doped GaN layer 3 of 0.5 micron thickness and the n type GaN resilient coating 4 of mixing Si of 3.5 micron thickness, the doping content of silicon is 5 * 10 ¹⁷Cm ^-3To 5 * 10 ¹⁹Cm ^-3Between; Then temperature is reduced between 650～750 ℃, carrier gas switches to N2,5 In of growth on this resilient coating _0.2Ga _0.8N (2.5nm)/In _0.8Ga _0.2N (0.5nm)/GaN (10nm), wherein the molar flow of TEGa is 0.1 * 10 ^-5Moles/min to 1.5 * 10 ^-5Moles/min, the molar flow of TMIn are 5 * 10 ^-5Moles/min to 10 * 10 ^-5Between the moles/min, the flow of NH3 is 12 liters/minute, then temperature is increased to 1000～1100 ℃, and H2 does carrier gas, the thick p type Al of growth 25nm _0.15Ga _0.85The p type GaN layer that N and 200nm are thick, the Mg doping content is 5 * 10 ¹⁹Cm ^-3To 5 * 10 ²⁰Cm ^-3Between.

Embodiment two

Utilize the green light LED of MOCVD equipment epitaxial growth high brightness, used substrate is the sapphire of (001) face.As shown in Figure 1, at first in the MOCVD reative cell Sapphire Substrate 1 is heated to 1200 ℃, handles 5min under H2, temperature is reduced to 500～600 ℃ of growing GaN nucleating layers 2 then, the about 30nm of thickness; Temperature rises to 1160 ℃ then, H2 does carrier gas, with the GaN resilient coating of 3.0 microns/hour growth rate epitaxial growth 4 micron thickness, comprising the involuntary Doped GaN layer 3 of 0.5 micron thickness and the n type GaN resilient coating 4 of mixing Si of 3.5 micron thickness, the doping content of silicon is 5 * 10 ¹⁷Cm ^-3To 5 * 10 ¹⁹Cm ^-3Between; Then temperature is reduced between 650～750 ℃, carrier gas switches to N2,5 In of growth on this resilient coating _0.2Ga _0.8N (2.5nm)/Al _0.8Ga _0.2N (0.5nm)/GaN (10nm), wherein the molar flow of TEGa is 0.1 * 10 ^-5Mole moles/min to 1.5 * 10 ^-5The mole moles/min, the molar flow of TMIn is 5 * 10 ^-5The mole moles/min, the molar flow of TMA1 is 1.0 * 10 ^-5The mole moles/min, the flow of NH3 is 12 liters/minute, then temperature is increased to 1000～1100 ℃, H2 does carrier gas, the thick p type Al of growth 25nm _0.15Ga _0.85The p type GaN layer that N and 200nm are thick, the Mg doping content is 5 * 10 ¹⁹Cm ^-3To 5 * 10 ²⁰Cm ^-3Between.

The present invention mainly passes through to introduce the method minimizing InGaN of one deck insert layer and the V-type defective between GaN in epitaxial growth InGaN/GaN quantum well, and reduces separating out of In component, thereby the acquisition high brightness, the green light LED that antistatic effect is strong.This insert layer is In _yGa _1-yN, x＜y≤1 wherein, (0.15≤x≤0.35), and the thickness 0.1～5nm of this layer, because the In content of introducing increases, it can reach dynamic equilibrium with the In that separates out, thereby reduce separating out of In, and can reduce InGaN quantum well and GaN stress and the V-type defective between building, thereby obtain high brightness, the green light LED that antistatic effect is strong.

This insert layer is Al _yGa _1-yN, the thickness of wherein 0＜y≤1, and this layer are 0.1～5nm, because the Al-N key is strong, can prevent the volatilization of In behind the introducing Al, and because Al _yGa _1-yThe potential barrier of N is bigger, can improve the restriction to charge carrier, strengthens the recombination probability in electronics and hole, thereby the acquisition high brightness, the green light LED that antistatic effect is strong.

This insert layer is Al _aIn _bGa _1-a-bN, wherein 0＜a＜1,0＜b＜1 and a, the value of b need satisfy the potential barrier that its potential barrier is higher than GaN, and the thickness of this layer is 0.1～5nm.

This insert layer is In _cAl _1-cN, x＜c≤1 wherein, the thickness of this layer is 0.1～5nm.

The InGaN/GaN Multiple Quantum Well that comprises above insert layer is applicable to but is not limited to green light LED, and the number of quantum well has N, N more than or equal to 1 smaller or equal to 20.

After tested, after the introducing insert layer, the brightness under the 20mA of the green light LED chip of 300 microns * 300 microns 520nm is increased to 250mcd by 100mcd, and the antistatic effect of chip is increased to Human Body Model 4000V by Human Body Model 500V.

Above embodiment is the unrestricted technical scheme of the present invention in order to explanation only.Any technical scheme that does not break away from spirit and scope of the invention all should be encompassed in the middle of the patent claim of the present invention.

Claims (2)

1. the manufacture method of a green light LED, it adopts the MOCVD method, utilizes high-purity N H ₃Do the N source, trimethyl gallium or triethyl-gallium are done the gallium source, and trimethyl indium is done the indium source, and trimethyl aluminium is done the aluminium source, and silane is as n type dopant, and two luxuriant magnesium is characterized in that as p type dopant this method may further comprise the steps:

Step 1 is being used H under the high temperature in the MOCVD reative cell ₂Processing Sapphire Substrate surface, the growing low temperature nucleating layer of lowering the temperature is then followed growing GaN resilient coating at high temperature, and this GaN resilient coating comprises non-Doped GaN layer and mixes the n type GaN layer of Si;

Step 2 is reduced to temperature between 650～750 ℃, and carrier gas switches to N ₂, In grows on the GaN resilient coating _xGa _1-xThe N/GaN quantum well, 0.15≤x≤0.35 wherein, described In _xGa _1-xThe N/GaN quantum well comprises InGaN trap layer, and insert layer and GaN build layer, and wherein the molar flow of TEGa is 0.1 * 10 ^-5～1.5 * 10 ^-5Moles/min, the molar flow of TMIn are 5 * 10 ^-5～10 * 10 ^-5The molar flow of moles/min or TMAl is 0～1.0 * 10 ^-5Moles/min, NH ₃Flow be 12 liters/minute; This insert layer is In _yGa _1-yN, wherein x＜y≤1; Or Al _zGa _1-zN, wherein 0＜z≤1;

Step 3 is at In _xGa _1-xGenerate p type AlGaN electronic barrier layer and p type GaN layer on the N/GaN quantum well layer.

2. the manufacture method of a kind of green light LED as claimed in claim 1, it is characterized in that: the number of described quantum well is 1～20.

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