CN108807609B - Preparation method of metal nanoparticle modified patterned substrate L ED - Google Patents

Abstract

The invention discloses a preparation method of a patterned substrate L ED modified by metal nanoparticles, which comprises the following steps of 1) forming a layer of metal thin film on the patterned substrate, rapidly heating to 750-1200 ℃, annealing for 1-10min, and forming the metal nanoparticles on the patterned substrate, 2) transferring the patterned substrate to an MOCVD (metal organic chemical vapor deposition) growth chamber to grow a buffer layer, 3) growing u-type GaN, n-type GaN, InGaN/GaN quantum wells, AlGaN electron barrier layers and p-type GaN to obtain the patterned substrate L ED. modified by the metal nanoparticles.

Description

Preparation method of patterned substrate LED decorated with metal nanoparticles

technical field

The invention belongs to the technical field of LEDs, and in particular relates to a preparation method of a patterned substrate LED decorated with metal nanoparticles.

Background technique

In order to improve the epitaxial effect of epitaxial growth of GaN thin films on patterned sapphire substrates, usually: (1) by using a thicker AlN or AlGaN buffer layer; (2) growing an AlN buffer layer first, but the AlN buffer layer is Overetching patterns; (3) Introducing an AlN or SiN insertion layer in the buffer layer. However, these methods all have certain disadvantages. For example, the disadvantage of methods (1) and (3) is that the thickness of the buffer layer is large, and the required raw materials increase, which will increase the cost; During overlay etching, the sample needs to be taken out, and then put in for growth after the etching is completed; and the etching process is also relatively complicated, requiring steps such as gluing, photolithography, cleaning, ICP etching, cleaning, etc. Increased processing costs.

Therefore, it is necessary to develop a patterned substrate LED decorated with metal nanoparticles, which can be simple in processing procedure, low in cost, reduce the thickness of the buffer layer, reduce the dislocation density, and improve the epitaxial effect.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a metal nanoparticle-modified patterned substrate LED with simple processing procedure and low cost, which can reduce the thickness of the buffer layer, reduce the dislocation density, and improve the epitaxial effect.

The technical scheme adopted in the present invention is: a preparation method of a patterned substrate LED decorated with metal nanoparticles, comprising the following steps:

1) A layer of metal film is formed on the patterned substrate, rapidly heated to 750-1200°C, and annealed for 1-10 minutes, then metal nanoparticles can be formed on the patterned substrate;

2) Transfer to MOCVD growth chamber to grow AlN or AlGaN buffer layer;

3) Grow u-type GaN, n-type GaN, InGaN/GaN quantum well, AlGaN electron blocking layer and p-type GaN, and then a patterned substrate LED decorated with metal nanoparticles can be obtained.

Preferably, the metal thin film is Ag thin film, Au thin film, In thin film or Al thin film; and the metal nanoparticle is Ag nanoparticle, Au nanoparticle, In nanoparticle or Al nanoparticle.

Preferably, in step 1), the specific method in the form of metal nanoparticles is: using electron beam evaporation equipment to evaporate a layer of Au film or Ag film on the patterned substrate, the evaporation current is 100-150A, and the vacuum is 1× 10 ^-6 -1×10 ^-3 Pa, under N ₂ protective atmosphere, rapidly heated to 750-1200 ℃, annealed for 0.5-5min, Au nanoparticles or Ag nanoparticles can be formed on the patterned substrate. More preferably, the evaporation current is 120A, the vacuum is 1×10 ^-4 Pa, the temperature is rapidly raised to 800° C. under a N ₂ protective atmosphere, and the annealing time is 1 min.

Preferably, in step 1), the specific method in the form of metal nanoparticles is: placing the patterned substrate in a MOCVD growth chamber, and at 400-600 ° C, passing In metal organic compounds or Al metal at a flow rate of 350-600 sccm For organic matter, lay a layer of In film or Al film, then, under the condition of vacuum degree greater than 10 ^-3 Pa, rapidly heat up to 750-1200℃, anneal for 1-10min, then In nanoparticles can be formed on the patterned substrate or Al nanoparticles.

In step 2), an AlN or AlGaN buffer layer is grown according to a conventional process using metal nanoparticles as a mask. The lateral epitaxial overgrowth of the buffer layer is improved, the dislocation density is reduced, and the purpose of improving the epitaxial effect is achieved.

Preferably, the In metal organic compound is trimethyl indium or diethyl indium; the Al metal organic compound is trimethyl aluminum or diethyl aluminum.

Preferably, the thickness of the metal thin film is 6-30 nm. More preferably, the thickness of the metal thin film is 10 nm. The thickness of the buffer layer is 2-20 nm.

Preferably, the diameter of the metal nanoparticles is 2-6 nm.

Preferably, the patterned substrate is a patterned sapphire substrate.

The beneficial effects of the present invention are as follows: the present invention uses metal nanoparticles as a mask to improve the lateral epitaxial overgrowth of the buffer layer and reduce the dislocation density, thereby achieving the purpose of improving the epitaxial effect; the use of metal nanoparticles is conducive to reducing buffering The thickness of the layer can reduce the production cost; Au or Ag nanoparticles have better light reflection characteristics, which can emit the light emitted by the active layer and the light reflected from the surface of the LED, thereby improving the light extraction efficiency of the LED device; The metal nanoparticle-modified patterned substrate of the present invention has a simple preparation method and a wide range of applications.

Description of drawings

FIG. 1 is a schematic diagram of the formation process of metal nanoparticles, wherein 11 is a patterned sapphire substrate, and 12 is metal nanoparticles.

FIG. 2 is a schematic diagram of the growth of an AlGaN buffer layer on a patterned sapphire substrate LED decorated with metal nanoparticles, wherein 11 is a patterned sapphire substrate, 12 is a metal nanoparticle, and 13 is a buffer layer.

3 is the X-ray rocking curve (XRC) of the LED epitaxial wafer; wherein (a) is the X-ray rocking curve (XRC) of the LED epitaxial wafer without metal nanoparticles in the prior art; (b) is the preparation of Example 1 X-ray rocking curves of LED epitaxial wafers.

FIG. 4 is a photoluminescence (PL) spectrum of the LED epitaxial wafer prepared in Example 1. FIG.

Detailed ways

The invention provides a preparation method of a patterned substrate LED decorated with metal nanoparticles, comprising the following steps:

1) A layer of metal film is formed on the patterned substrate, rapidly heated to 750-1200°C, and annealed for 1-10 minutes, then metal nanoparticles can be formed on the patterned substrate;

2) Transfer to the MOCVD growth chamber to grow the buffer layer;

3) Grow u-type GaN, n-type GaN, InGaN/GaN quantum well, AlGaN electron blocking layer and p-type GaN, and then a patterned substrate LED decorated with metal nanoparticles can be obtained.

Preferably, the specific method in the form of metal nanoparticles is: using electron beam evaporation equipment to evaporate a layer of Au film or Ag film on the patterned substrate, the evaporation current is 100-150A, and the vacuum is 1×10 ^-6 -1 ×10 ^-3 Pa, in a N ₂ protective atmosphere, the temperature is rapidly increased to 750-1200°C, and annealed for 0.5-5min, then Au nanoparticles or Ag nanoparticles can be formed on the patterned substrate.

Preferably, the specific method in the form of metal nanoparticles is as follows: placing the patterned substrate in a MOCVD growth chamber, at 400-600° C., passing In metal organic matter or Al metal organic matter at a flow rate of 350-600 sccm, and laying a layer of In thin film or Al thin film, then, under the condition of vacuum degree greater than 10 ^-3 Pa, the temperature is rapidly heated to 750-1200 ℃, and annealed for 1-10 minutes, then In nanoparticles or Al nanoparticles can be formed on the patterned substrate.

Fig. 1 is a schematic diagram of the formation process of Ag metal nanoparticles, wherein, 11 is a patterned sapphire substrate, and 12 is a metal nanoparticle; first, a layer of Ag metal thin film is deposited on the patterned sapphire substrate, and then under a _N2 protective atmosphere , high temperature rapid annealing, can obtain Ag metal nanoparticles.

FIG. 2 is a schematic diagram of the growth of AlGaN on a patterned sapphire substrate LED decorated with metal nanoparticles, 11 is a patterned sapphire substrate, 12 is a metal nanoparticle, and 13 is a buffer layer. The metal nanoparticles can act as a mask to improve the lateral epitaxial overgrowth of the buffer layer, so as to achieve the purpose of improving the epitaxial effect.

Example 1

A preparation method of a patterned substrate LED decorated with metal nanoparticles, comprising the following steps:

1) Using electron beam evaporation equipment, a layer of Ag film with a thickness of 10 nm was evaporated on the patterned sapphire substrate, the evaporation current was 120 A, and the vacuum was 1 × 10 ^-4 Pa. Under the _N2 protective atmosphere, the temperature was rapidly increased to After annealing at 800°C for 1min, Ag nanoparticles with a diameter of 3nm can be formed on the patterned substrate;

2) Transfer to a MOCVD growth chamber to grow an AlGaN buffer layer with a thickness of 5 nm;

3) Grow u-type GaN, n-type GaN, InGaN/GaN quantum well, AlGaN electron blocking layer and p-type GaN, and then a patterned sapphire substrate LED decorated with metal nanoparticles can be obtained.

3 shows the X-ray rocking curve of the LED epitaxial wafer, wherein (a) is the X-ray rocking curve (XRC) of the LED epitaxial wafer without metal nanoparticles in the prior art; (b) is the LED prepared in Example 1 X-ray rocking curves of epitaxial wafers. As shown in Fig. 3(b), the XRC half width of the LED epitaxial wafer prepared in Example 1 is 201 arcsec, which is better than that of the LED epitaxial wafer without Ag nanoparticles (244 arcsec c).

4 is the PL spectrum of the LED epitaxial wafer prepared in Example 1, the intensity of which is 1.5-2 times that of the LED epitaxial wafer without Ag nanoparticles, and the light extraction efficiency is increased by 3-5%.

Example 2

A preparation method of a patterned substrate LED decorated with metal nanoparticles, comprising the following steps:

1) Using electron beam evaporation equipment, a layer of Au film with a thickness of 6nm was evaporated on the patterned sapphire substrate, the evaporation current was 100A, the vacuum was ₁ × ^10-3 Pa, and the temperature was rapidly increased to Au nanoparticles with a diameter of 2nm can be formed on the patterned substrate by annealing at 750℃ for 5min;

2) Transfer to the MOCVD growth chamber to grow an AlN buffer layer with a thickness of 2 nm;

3) Grow u-type GaN, n-type GaN, InGaN/GaN quantum well, AlGaN electron blocking layer and p-type GaN, and then a patterned sapphire substrate LED decorated with metal nanoparticles can be obtained.

Example 3

A preparation method of a patterned substrate LED decorated with metal nanoparticles, comprising the following steps:

1) Using electron beam evaporation equipment, an Au film with a thickness of 15 nm was evaporated on the patterned sapphire substrate, the evaporation current was 150 A, and the vacuum was 1 × 10 ^-5 Pa. Under the _N2 protective atmosphere, the temperature was rapidly increased to Au nanoparticles with a diameter of 5nm can be formed on the patterned sapphire substrate by annealing at 1000℃ for 2min;

2) Transfer to the MOCVD growth chamber to grow an AlN buffer layer with a thickness of 8 nm;

3) Grow u-type GaN, n-type GaN, InGaN/GaN quantum well, AlGaN electron blocking layer and p-type GaN, and then a patterned sapphire substrate LED decorated with metal nanoparticles can be obtained.

Example 4

A preparation method of a patterned substrate LED decorated with metal nanoparticles, comprising the following steps:

1) Put the patterned sapphire substrate in the MOCVD growth chamber, pass trimethyl indium at a flow rate of 350sccm at 400°C, and lay a layer of In thin film with a thickness of 12nm, then, under the vacuum degree greater than 10 ^-3 Pa Under the condition of high temperature, the temperature is rapidly increased to 900 °C, and annealed for 1 min to form In nanoparticles with a diameter of 3 nm on the patterned substrate;

2) Transfer to the MOCVD growth chamber to grow an AlN buffer layer with a thickness of 5 nm;

3) Grow u-type GaN, n-type GaN, InGaN/GaN quantum well, AlGaN electron blocking layer and p-type GaN, and then a patterned sapphire substrate LED decorated with metal nanoparticles can be obtained.

Example 5

A preparation method of a patterned substrate LED decorated with metal nanoparticles, comprising the following steps:

1) Put the patterned sapphire substrate in the MOCVD growth chamber, at 500°C, pass in trimethylaluminum at a flow rate of ^500sccm , and lay down an Al thin film with a thickness of 15nm. Under the condition of Pa, the temperature is rapidly increased to 1000 °C and annealed for 5 min to form Al nanoparticles with a diameter of 5 nm on the patterned substrate;

2) Transfer to a MOCVD growth chamber to grow an AlGaN buffer layer with a thickness of 10 nm;

3) Grow u-type GaN, n-type GaN, InGaN/GaN quantum well, AlGaN electron blocking layer and p-type GaN, and then a patterned sapphire substrate LED decorated with metal nanoparticles can be obtained.

Example 6

A preparation method of a patterned substrate LED decorated with metal nanoparticles, comprising the following steps:

1) Put the patterned sapphire substrate in the MOCVD growth chamber, at 600°C, pass in diethylaluminum at a flow rate of ^600sccm , and lay down an Al thin film with a thickness of 20nm. Under the condition of Pa, the temperature is rapidly increased to 1200 °C, and annealed for 8 min, Al nanoparticles with a diameter of 6 nm can be formed on the patterned substrate;

2) Transfer to a MOCVD growth chamber to grow an AlN buffer layer with a thickness of 12 nm;

3) Grow u-type GaN, n-type GaN, InGaN/GaN quantum well, AlGaN electron blocking layer and p-type GaN, and then a patterned sapphire substrate LED decorated with metal nanoparticles can be obtained.

Claims (5)

1. A method for preparing a patterned substrate L ED decorated by metal nano-particles is characterized by comprising the following steps:

1) forming a layer of metal film on the patterned substrate, rapidly heating to 750-1200 ℃, and annealing for 1-10min to form metal nanoparticles with the diameter of 2-6nm on the patterned substrate;

2) transferring the substrate to an MOCVD growth chamber, and growing a buffer layer with the thickness of 2-20 nm;

3) growing u-type GaN, n-type GaN, InGaN/GaN quantum wells, AlGaN electron blocking layers and p-type GaN to obtain a patterned substrate L ED modified by metal nanoparticles;

the metal film is an Ag film, an Au film, an In film or an Al film; the metal nanoparticles are Ag nanoparticles, Au nanoparticles, In nanoparticles or Al nanoparticles;

in the step 1), the specific method of the metal nano particle form is to use electron beam evaporation equipment to evaporate a layer of Au film or Ag film on the patterned substrate, wherein the evaporation current is 100-150A, and the vacuum is 1 × 10^-6-1×10^-3Pa, rapidly heating to 750-1200 ℃ under the protection of N, and annealing for 0.5-5min to form Au nanoparticles or Ag nanoparticles on the patterned substrate;

in the step 1), the specific method for the metal nanoparticle form is as follows: placing the patterned substrate In an MOCVD growth chamber, introducing an In metal organic substance or an Al metal organic substance at the temperature of 400-600 ℃ and the flow rate of 350-600sccm, laying an In thin film or an Al thin film, and then, keeping the vacuum degree to be more than 10^-3Under the condition of Pa, rapidly heating to 750-1200 ℃, annealing for 1-10min, and then forming In nano particles or Al nano particles on the patterned substrateParticles.

2. The method according to claim 1, wherein the In metallorganics are trimethyl indium or diethyl indium; the Al metal organic matter is trimethyl aluminum or diethyl aluminum.

3. The production method according to claim 1, wherein in the step 2), the buffer layer is an AlN buffer layer or an AlGaN buffer layer.

4. The production method according to claim 1, wherein the thickness of the metal thin film is 6 to 30 nm.

5. The method of manufacturing according to claim 1, wherein the patterned substrate is a patterned sapphire substrate.

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