CN102969416A

CN102969416A - Nitride light-emitting diode (LED) epitaxial wafer and growing method thereof

Info

Publication number: CN102969416A
Application number: CN201210429391XA
Authority: CN
Inventors: 李鸿渐; 李盼盼; 李志聪; 李璟; 王国宏
Original assignee: YANGZHOU ZHONGKE SEMICONDUCTOR LIGHTING CO Ltd
Current assignee: YANGZHOU ZHONGKE SEMICONDUCTOR LIGHTING CO Ltd
Priority date: 2012-11-01
Filing date: 2012-11-01
Publication date: 2013-03-13

Abstract

The invention provides a nitride light-emitting diode (LED) epitaxial wafer and a growing method thereof and relates to the technical field of semiconductor optoelectronics. The nitride LED epitaxial wafer structurally and sequentially comprises a substrate, a low-temperature buffer layer, an unintentionally doped GaN, an N-shaped electron-injection layer, an InGaN/GaN inserting layer, an active area, an electron blocking layer, a u-GaN/p-GaN superlattice and a p-GaN hole-injection layer from bottom to top. The InGaN/GaN inserting layer is grown between the N-shaped electron-injection layer and the active area so as to effective relieve stress of the active area, lower polarization electric fields, reduce limitation of stark effect through a quantum well, and improve luminance and anti-static properties. The u-GaN/p-GaN superlattice is inserted between the electron blocking layer and the P-shaped hole-injection layer so as to improve current expansion capacity and lower chip operating voltage.

Description

A kind of nitride LED epitaxial wafer and growing method thereof

Technical field

The invention belongs to the optical semiconductor electro-technical field, refer to especially a kind of production technical field of nitride LED epitaxial wafer.

Background technology

Nitride LED as solid state light emitter have efficiently, the advantages such as long-life, environmental protection, be described as the historical second revolution of human illumination behind the Edison invented electric light, become the in the world focus of semiconductor and lighting field research and development and industry concern.But obtain high brightness GaN-based LED, also face technically many difficult problems.

One of them subject matter is that the stress field that lattice mismatch causes in the InGaN/GaN Multiple Quantum Well causes radiation recombination efficiency to reduce.The stress field that lattice mismatch causes among the InGaN/GaN Multiple Quantum Well MQWs causes electronics and hole wave function that the space occurs and separates, thereby reduce the radiation recombination probability, the reduction luminosity so that can be with run-off the straight among the MQWs.It is breakdown that these stress fields of while cause led chip to be easy to owing to being caused by electrostatic interaction, i.e. antistatic special ability.

On the other hand, increasing current expansion efficiency in the LED structural design at present is an important channel of improving brightness, but current extending generally designs at chip, complex process and increase cost.The design current extension layer is a kind of more cost-effective method on the LED epitaxial structure.

Summary of the invention

The present invention seeks to propose a kind of nitride LED epitaxial wafer that can add the electric current extended capability, improve luminosity.

The present invention includes N-type electron injecting layer, P type hole injection layer and be clipped in described N-type electron injecting layer and P type hole injection layer between the Multiple Quantum Well active area, and between described Multiple Quantum Well active area and described P type hole injection layer, comprise an electronic barrier layer, it is characterized in that, 1～50 pair of N-type InGaN/GaN insert layer is set between described N-type electron injecting layer and Multiple Quantum Well active area, and 1～50 pair of P type u-GaN/p-GaN superlattice layer is set between described electronic barrier layer and P type hole injection layer.

The present invention reduces polarized electric field by growth N-type InGaN/GaN insert layer between Multiple Quantum Well active area and N-type electron injecting layer to alleviate the stress in the active area, increases radiation recombination; Between electronic barrier layer and P type hole injection layer, insert simultaneously the u-GaN/p-GaN superlattice layer, can increase the current expansion ability, improve luminosity and reduce operating voltage.

Another purpose of the present invention is the growing method that proposes above nitride LED epitaxial wafer.

The present invention successively the GaN layer of growing low temperature GaN resilient coating, involuntary doping and N-type electron injecting layer on substrate; It is characterized in that grow doping concentration is 1 * 10 on the N-type electron injecting layer ¹⁷Cm ^-3～5 * 10 ¹⁹Cm ^-31～50 pair of N-type InGaN/GaN insert layer; On N-type InGaN/GaN insert layer, grow successively again Multiple Quantum Well active area and electronic barrier layer; At described electronic barrier layer 1～50 pair of u-GaN/p-GaN superlattice layer of growing; Last growing P-type hole injection layer on the u-GaN/p-GaN superlattice layer again.

Technique of the present invention is reasonable, convenient production, and product stability is good, and qualification rate is high.

Adopt the nitride epitaxial sheet of the present invention's growth to make the 10min*23min led chip with standard chips technique, because the introducing of InGaN/GaN insert layer, luminosity has obtained increasing substantially, the antistatic property (ESD) of led chip has obtained very large improvement simultaneously, and ESD reaches more than 95% greater than the 4000V percent of pass under static electricity on human body's pattern; Use u-GaN/p-GaN superlattice insert layer, the voltage of led chip has obtained reduction, and operating voltage drops to 3.0V from 3.2V under the 10mil*23mil chip 20mA.

In addition, the growth temperature of described N-type InGaN/GaN insert layer quantum well and quantum in above-mentioned Multiple Quantum Well active area built between the growth temperature.Its purpose mainly is the cushioning layer material that growth one deck is built between quantum well and quantum, and the active area growth stress discharges after being conducive to, and obtains the active area quantum well of better quality.

When the growth of described N-type InGaN/GaN insert layer, can only carry out N-type to InGaN and mix, perhaps only GaN is mixed, also can mix to InGaN/GaN simultaneously.Dopant selects Si etc. to can be used as the element that N-type is mixed.

When the growth of described N-type InGaN/GaN insert layer, can adopt the superlattice growth mode to grow, it is several to thicker InGaN/GaN also can to grow, and the thickness of every layer of InGaN is 1～500, and the thickness of every layer of GaN is 1～2000.

When the described u-GaN/p-GaN superlattice layer of growth, the element M g that can also adopt the P type to mix mixes to the p-GaN layer, and doping content is 1 * 10 ¹⁷Cm ^-3～5 * 10 ²¹Cm ^-3In described doping content scope, be conducive to the activation of Mg, to obtain higher hole concentration, improve hole injection efficiency, and then improve brightness.

When the described u-GaN/p-GaN superlattice layer of growth, the thickness of every layer of u-GaN is 1～500, and the thickness of every layer of p-GaN is 1～2000.Adopt the u-GaN/p-GaN superlattice, Mg mixes and is similar to the Delta doping, more is conducive to favourable acquisition high hole concentration, improves luminosity.

Description of drawings

Fig. 1 is a kind of structural representation of nitride LED epitaxial wafer of the present invention.

Among the figure, 100: substrate; 101: low temperature buffer layer; 102: non-Doped GaN; 103:N type electron injecting layer; 104:N type InGaN/GaN insert layer; 105: the Multiple Quantum Well active area; 106: electronic barrier layer; The 107:u-GaN/p-GaN superlattice; The 108:p-GaN hole injection layer.

Embodiment

Growth course adopts MOCVD equipment (31 business PCs of the Crius of Aixtron company), and used group V source is ammonia (NH ₃), the organic source material of III family is trimethyl gallium (TMGa) and trimethyl indium (TMIn), the dopant well element of P type and N-type adopts respectively Mg and Si.Substrate can be selected sapphire, silicon, carborundum or GaAs.

In conjunction with Fig. 1, growth step:

1, be the GaN low temperature buffer layer 101 of 0.01～1 μ m in substrate 100 growth a layer thickness, with H ₂As carrier gas, growth temperature is 500～600 ℃, and pressure is 50～1000mbar.This routine thickness is 30 nm.

2, heat up, under temperature is 800～1200 ℃, the condition of pressure 50～1000 mbar, be about the GaN layer 102 of the involuntary doping of 2 μ m in GaN low temperature buffer layer 101 growth a layer thickness.

3, heating up, on the GaN of involuntary doping layer 102, is 800～1200 ℃ in temperature again, under the condition of pressure 50～1000 mbar, adopts Si or other can realize the element that N-type is mixed, and carrying out doping content is 1 * 10 ¹⁹Cm ^-3The growth of N-type electron injecting layer 103, thickness is 0.1～5 μ m, this example is 2 μ m.

4, switch to N ₂Condition, carry out the growth of InGaN/GaN insert layer 104 at N-type electron injecting layer 103: minute two sections growths, 3 couples of InGaN/GaN of phase I growth, growth temperature is 940 ℃, and the thickness of every layer of InGaN is 3 nm, and the thickness of every layer of GaN is 40nm.The doping content of GaN is 1 * 10 ¹⁸Cm ^-3, the doping content of InGaN is 6 * 10 ¹⁷Cm ^-320 pairs of InGaN/GaN superlattice layers of second stage growth, growth temperature is 780 ℃, and the thickness of every layer of InGaN is 1 nm, and the thickness of every layer of GaN is 3 nm, wherein GaN is carried out N-type and mixes, and doping content is 6 * 10 ¹⁷Cm ^-3

6, the Multiple Quantum Well active area 105 of on InGaN/GaN insert layer 104, growing according to a conventional method.

7, conventional method growth electronic barrier layer 106 on Multiple Quantum Well active area 105.

8, on electronic barrier layer 106, adopt N ₂As carrier gas, carry out the growth of 3 pairs of u-GaN/p-GaN superlattice layers 107, the thickness of every layer of u-GaN is 5 nm, and the thickness of every layer of p-GaN is 5 nm, and the Mg doping content is 1 * 10 among the p-GaN ¹⁷～5 * 10 ²¹Cm ^-3

9, conventional method growth p-GaN hole injection layer 108 on u-GaN/p-GaN superlattice layer 107.

Claims

1. nitride LED epitaxial wafer, comprise N-type electron injecting layer, P type hole injection layer and be clipped in described N-type electron injecting layer and P type hole injection layer between the Multiple Quantum Well active area, and between described Multiple Quantum Well active area and described P type hole injection layer, comprise an electronic barrier layer, it is characterized in that, 1～50 pair of N-type InGaN/GaN insert layer is set between described N-type electron injecting layer and Multiple Quantum Well active area, and 1～50 pair of P type u-GaN/p-GaN superlattice layer is set between described electronic barrier layer and P type hole injection layer.

2. the growing method of nitride LED epitaxial wafer as claimed in claim 1, successively the GaN layer of growing low temperature GaN resilient coating, involuntary doping and N-type electron injecting layer on substrate; It is characterized in that grow doping concentration is 1 * 10 on the N-type electron injecting layer ¹⁷Cm ^-3～5 * 10 ¹⁹Cm ^-31～50 pair of N-type InGaN/GaN insert layer; On N-type InGaN/GaN insert layer, grow successively again Multiple Quantum Well active area and electronic barrier layer; At described electronic barrier layer 1～50 pair of u-GaN/p-GaN superlattice layer of growing; Last growing P-type hole injection layer on the u-GaN/p-GaN superlattice layer again.

3. the growing method of described nitride LED epitaxial wafer according to claim 2, the growth temperature that it is characterized in that described N-type InGaN/GaN insert layer quantum well and quantum in above-mentioned Multiple Quantum Well active area are built between the growth temperature.

4. according to claim 2 or the growing method of 3 described nitride LED epitaxial wafers, it is characterized in that when the growth of described N-type InGaN/GaN insert layer, only InGaN is carried out N-type and mix.

5. according to claim 2 or the growing method of 3 described nitride LED epitaxial wafers, it is characterized in that when the growth of described N-type InGaN/GaN insert layer, only GaN is mixed.

6. according to claim 2 or the growing method of 3 described nitride LED epitaxial wafers, it is characterized in that when the growth of described N-type InGaN/GaN insert layer, simultaneously InGaN/GaN being mixed.

7. according to claim 2 or the growing method of 3 described nitride LED epitaxial wafers, it is characterized in that when the growth of described N-type InGaN/GaN insert layer, adopt the superlattice growth mode to grow.

8. according to claim 2 or the growing method of 3 described nitride LED epitaxial wafers, it is characterized in that when the growth of described N-type InGaN/GaN insert layer, it is several to thicker InGaN/GaN to grow, and the thickness of every layer of InGaN is 1～500, and the thickness of every layer of GaN is 1～2000.

9. the growing method of described nitride LED epitaxial wafer according to claim 2 is characterized in that when the described u-GaN/p-GaN superlattice layer of growth, the element that adopts the P type to mix carries out Mg to the p-GaN layer and mixes, and doping content is 1 * 10 ¹⁷Cm ^-3～5 * 10 ²¹Cm ^-3

10. the growing method of described nitride LED epitaxial wafer according to claim 2 is characterized in that the thickness of every layer of u-GaN is 1～500 when the described u-GaN/p-GaN superlattice layer of growth, and the thickness of every layer of p-GaN is 1～2000.