CN106328773B - A kind of iii-nitride light emitting devices and preparation method thereof - Google Patents

Abstract

The invention discloses a nitride light-emitting diode and a manufacturing method thereof. A composite structure of a stress control layer/reflection layer/electromagnetic field generating layer is inserted into a P-type nitride and an N-type nitride. When a current passes through the electromagnetic field generating layer, due to Electromagnetic induction generates a magnetic field, and controls the stress control layer to generate stress, thereby regulating the type and magnitude of stress received by multiple quantum wells, improving the o-light ratio of light-emitting diodes and the carrier transition recombination efficiency of quantum wells, improving luminous efficiency and improving the efficiency droop effect .

Description

A nitride light-emitting diode and its manufacturing method

technical field

The invention relates to the field of semiconductor optoelectronic devices, in particular to a nitride light-emitting diode and a manufacturing method thereof.

Background technique

Nowadays, light-emitting diodes (LEDs), especially nitride light-emitting diodes, have been widely used in the field of general lighting due to their high luminous efficiency. Group III nitride light-emitting diodes are uniaxial dielectric crystals, and there are two different solutions to the wave equation. One kind of ordinary light propagates along the optical axis, referred to as o light (Ordinary Light), and its electric field E is perpendicular to the optical axis E⊥c ; Another extraordinary ray propagating perpendicular to the optical axis, referred to as e light (Extraordinary), its electric field E is parallel to the optical axis E∥c. The o light is the transition of electrons from the bottom of the conduction band to the heavy hole band and the light hole band, and the e light is the transition of electrons from the bottom of the conduction band to the hole band split by the crystal field. For III-nitride light-emitting diodes, the luminescence of the material is mainly the recombination of electrons from the bottom of the conduction band to the top of the valence band. Due to the optical anisotropy of III-nitrides, light parallel to the c-axis is not easy to exit.

When the current flows in the nitride light-emitting diode, the electron injection will expand the crystal lattice, and at the same time, the thermal effect will change the stress of the substrate and the epitaxial layer, so that the compressive stress it receives will be reduced (reference: ScientificReports, 5 :17227; DOI: 10.1038/srep17227). As the injection current increases, the compressive stress gradually drops to zero and turns into tensile stress, accompanied by a sharp drop in luminous efficiency. In order to obtain higher luminous efficiency and improve the Efficiency Droop effect, it is necessary to increase the compressive stress of the nitride light-emitting diode under implantation conditions.

Contents of the invention

In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a nitride light-emitting diode and its manufacturing method, inserting a composite structure of stress control layer/reflective layer/electromagnetic field generating layer in P-type nitride and N-type nitride, When the current passes through the electromagnetic field generation layer, a magnetic field is generated due to electromagnetic induction, and the stress control layer generates stress, thereby regulating the type and magnitude of the stress received by the multi-quantum wells, and improving the o-light ratio of the light-emitting diode and the carrier transition recombination efficiency of the quantum wells , enhance luminous efficiency and improve efficiency droop effect.

According to the first aspect of the present invention: a nitride light-emitting diode, which sequentially includes a substrate, a buffer layer, an N-type nitride, multiple quantum wells, and a P-type nitride, is characterized in that: the P-type nitride and the N-type A composite structure composed of a stress control layer/reflection layer/electromagnetic field generation layer inserted into a type nitride.

The reflective layer is used to prevent the materials of the electromagnetic field generation layer and the stress control layer from absorbing the light emitted by the multi-quantum wells. When the current flows through the electromagnetic field generation layer, it will cause an electromagnetic induction effect and generate a magnetic field; the magnetic field controls the stress control layer to generate stress, thereby regulating the multi-quantum wells The type and size of the stress, improve the o-light ratio of the light-emitting diode and the carrier transition recombination efficiency of the quantum well, improve the luminous efficiency and improve the efficiency droop effect.

Further, the electromagnetic field generating layer generates a magnetic field by electromagnetic induction with the current injection of the light emitting diode, and the magnitude of the magnetic field is controlled by the magnetic material of the electromagnetic generating layer and the magnitude of the injected current.

Further, the position of inserting the stress control layer in the P-type nitride and the N-type nitride corresponds to each other, and the material of the stress control layer is a magnetoelastic material, and when subjected to a magnetic field, the lattice constant will change, thereby generating tension stress or compressive stress.

Further, the stress control layer has a thickness of 10-900 nm, preferably 500 nm.

Further, the material of the reflective layer is Al, DBR, ODR or a combination of the above three, preferably DBR.

Further, the electromagnetic field generating layer is a magnetic material, including Ni, Co, Mn, FeCo, Fe ₃ O ₄ , Cr ₂ O ₃ , Fe ₂ CrSi and other simple substances or nanospheres of compounds, with a size of 10-900nm, preferably 200nm .

According to a second aspect of the present invention: a method for manufacturing a nitride light-emitting diode, comprising the following steps:

(1) Epitaxial growth of buffer layer and N-type nitride on the substrate in sequence to form the first epitaxial wafer;

(2) Take the first epitaxial wafer out of the reaction chamber, etch the first channel on the N-type nitride, then deposit the electromagnetic field generating layer in sequence, and then deposit the reflective layer and magnetoelastic material to form the first template;

(3) Put the first template back into the MOCVD reaction chamber for secondary epitaxial growth of N-type nitride, multiple quantum wells, and P-type nitride to form a second epitaxial wafer;

(4) Take the second epitaxial wafer out of the reaction chamber, etch out the second channel, and then deposit the stress control layer, reflective layer and electromagnetic field generating layer in sequence. The coordinates of the channel correspond to the first channel one by one, forming the second channel. template;

(5) Put the second template back into the MOCVD reaction chamber, and perform epitaxial growth of P-type nitride three times to form the final third epitaxial wafer.

Further, the first channel and the second channel have a depth of 100-1000 nm, a length of 1-10 μm, and a width of 1-10 μm.

Description of drawings

FIG. 1 is a schematic diagram of a nitride light emitting diode according to an embodiment of the present invention.

FIG. 2 is a comparison diagram of the stress difference between the nitride light-emitting diode of the embodiment of the present invention and the traditional light-emitting diode under different currents.

Illustration: 100: substrate, 101: buffer layer, 102: N-type nitride, 103: electromagnetic field generating layer, 104: reflective layer, 105: stress control layer, 106: multiple quantum wells, 107: P-type layer.

Detailed ways

A nitride light-emitting diode proposed by the present invention sequentially includes a substrate 100, a buffer layer 101, an N-type nitride 102, a composite structure of a stress control layer 103/reflective layer 104/electromagnetic field generating layer 105, a multiple quantum well 106, P-type nitride 107, a composite structure of stress control layer/DBR/electromagnetic field generation layer inserted in P-type nitride 107 and N-type nitride 102, reflective layer 104 is used to prevent the electromagnetic field generation layer from absorbing light, when the current flows through the electromagnetic field When the layer 105 produces an electromagnetic induction effect, a magnetic field is generated; the magnetic field controls the stress to control the layer 103 to generate stress, thereby regulating the type and size of the stress received by the multi-quantum wells, improving the o-light ratio of the light-emitting diode and the carrier transition recombination efficiency of the quantum wells, Improve luminous efficiency and improve efficiency droop.

First, on the sapphire substrate 100, epitaxially grow the substrate 100, the buffer layer 101, and the N-type nitride 102 in order to form the first epitaxial wafer; then, take out the first epitaxial wafer, and etch the first epitaxial wafer on the N-type nitride 102. A channel with a depth of 1 μm, a length of 2 μm, and a width of 2 μm, respectively depositing an electromagnetic field generating layer of 200 nm FeCo nanospheres, and then depositing a DBR and a 500 nm magnetoelastic material as the stress control layer 103 to form a first template; then, Put the first template back into the MOCVD reaction chamber, perform secondary epitaxy, continue to grow N-type nitride to cover the composite structure of stress control layer 103/DBR reflectivity 104/electromagnetic field generation layer 105, and continue to grow multiple quantum wells 106 and P type nitride 107 to form a second epitaxial wafer; then, take out the second epitaxial wafer and etch a second trench with a depth of 1 μm, a length of 2 μm, and a width of 2 μm, and sequentially deposit 500 nm of magnetoelastic material on the trench Stress control layer 103, DBR reflective layer 104, and electromagnetic field generating layer 105 of FeCo nanospheres with a particle size of 200nm form a second template; finally, put the second template back into the MOCVD reaction chamber for three epitaxy to continue growing P-type nitride 107 , covering the composite structure of the stress control layer 103 /DBR reflective layer 104 /electromagnetic field generating layer 105 .

When the current flows through the electromagnetic field generating layer, a magnetic field is generated, and the magnetic field increases as the current rises, and the magnetoelastic material is controlled to generate compressive stress to offset the decrease in the compressive stress caused by the rise in the junction temperature of the light-emitting diode and the current injection. As shown in Figure 2; when the injection current is less than 300mA, the compressive stress generated by the electromagnetic field is less than the magnitude of the reduction of the compressive stress of the light-emitting diode, and the compressive stress received by the multiple quantum wells of the light-emitting diode shows a downward trend; when the injection current exceeds 300mA, The compressive stress generated by the electromagnetic field is greater than the reduction range of the compressive stress of the light-emitting diode, and the compressive stress suffered by the multiple quantum wells of the light-emitting diode shows an upward trend. The rising compressive stress can improve the o-light ratio of the light-emitting diode and the carrier transition recombination efficiency of the quantum well, improve the luminous efficiency and improve the efficiency droop.

The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the present invention. Therefore, all Equivalent technical solutions also belong to the category of the present invention, and the scope of patent protection of the present invention should be limited according to the scope of claims.

Claims (9)

1. a kind of iii-nitride light emitting devices successively include substrate, N-type nitride, multiple quantum wells and p-type nitride, spy Sign is：It is inserted into stress control layer/reflecting layer/electromagnetic field in the p-type nitride and N-type nitride, answering for layer composition occurs Structure is closed, the position that stress control layer is inserted into the p-type and N-type nitride corresponds, and Stress Control layer material is mangneto Elastic material, when by magnetic fields, lattice constant can change, to generate tensile stress or compression to multiple quantum wells.

2. a kind of iii-nitride light emitting devices according to claim 1, it is characterised in that：The reflecting layer is for preventing electricity Layer occurs for magnetic field and Stress Control layer material absorbs the light that multiple quantum wells issues.

3. a kind of iii-nitride light emitting devices according to claim 1, it is characterised in that：Layer occurs for the electromagnetic field with hair The electric current injection of optical diode causes electromagnetic induction to generate magnetic field, and the magnetic material and note of layer are occurred by electromagnetism for the size in the magnetic field Enter size of current control.

4. a kind of iii-nitride light emitting devices according to claim 1, it is characterised in that：The thickness of the stress control layer For 10 ~ 900nm.

5. a kind of iii-nitride light emitting devices according to claim 1, it is characterised in that：The material in the reflecting layer is Al Or DBR or ODR or aforementioned combinatorial.

6. a kind of iii-nitride light emitting devices according to claim 1, it is characterised in that：Layer occurs for the electromagnetic field Magnetic material selects Ni or Co or Mn or FeCo or Fe₃O₄Or Cr₂O₃Or Fe₂CrSi。

7. a kind of iii-nitride light emitting devices according to claim 6, it is characterised in that：The size of the magnetic material is 10~900nm。

8. a kind of production method of iii-nitride light emitting devices, comprises the steps of：

（1）Successively epitaxial growth buffer, N-type nitride form the first epitaxial wafer on substrate；

（2）First epitaxial wafer is taken out into reaction chamber, the first channel is etched on N-type nitride, is then sequentially depositing electromagnetic field Layer, redeposited reflecting layer and magnetoelastic material occurs, forms the first template；

（3）First template is reentered into MOCVD reaction chamber, secondary epitaxy is carried out and grows N-type nitride, multiple quantum wells, p-type nitrogen Compound forms the second epitaxial wafer；

（4）By the second epitaxial wafer take out reaction chamber, etch the second channel, be then sequentially depositing stress control layer, reflecting layer and Layer occurs for electromagnetic field, and the coordinate one-to-one correspondence of the channel and the first channel forms the second template；

（5）Second template is reentered into MOCVD reaction chamber, epitaxial growth p-type nitride three times is carried out, forms final third Epitaxial wafer.

9. a kind of production method of iii-nitride light emitting devices according to claim 8, it is characterised in that：First ditch Road, the second channel depth be 100 ~ 1000nm, length be 1 ~ 10 μm, width be 1 ~ 10 μm.