CN104900772B - The preparation method of light emitting diode - Google Patents

Abstract

The invention discloses a method for preparing a light-emitting diode, which has the beneficial effect of significantly increasing the reflection of light and enhancing the luminous efficiency of the light-emitting diode, and is achieved through the following steps: (1) providing a growth substrate; Deposit buffer layer, N-type layer, light-emitting layer and P-type layer; (3) Prepare N electrode and P electrode on N-type layer and P-type layer respectively; (4) Grind and thin the growth substrate backside; (5) Provide a Si substrate with the same diameter as the growth substrate; (6) Align the Si substrate with the back of the growth substrate; (7) Bond the Si substrate to the back of the growth substrate through a bonding process, and then grind Thinning to form a thin layer of Si; (8) Perform thermal oxidation reaction on the thin layer of Si on the back of the growth substrate to form a Si/SiO ₂ structure; (9) Cycle steps (5) to (8) to form n pairs of Si/SiO 2 DBR structure composed of _SiO2 .

Description

Manufacturing method of light-emitting diode

technical field

The invention belongs to the technical field of semiconductor light emitting, and in particular relates to a preparation method of a light emitting diode.

Background technique

With the application of light-emitting diodes more and more widely, further improving its luminous efficiency has become the research focus of the industry. Among them, the distributed Bragg reflector (DBR: Distributed Bragg Reflector) structure is prepared on the back of the light-emitting diode to effectively reflect light and improve luminescence. One of the effective means of diode luminous efficiency, the DBR structure on the back of the traditional light-emitting diode is usually deposited by evaporation to form a multi-layer SiO ₂ /TiO ₂ structure. However, the traditional evaporation DBR structure requires a large number of layers (20~40 layers) , there are too many interfaces, which will affect the quality of film formation, and there will inevitably be light loss at the interface; at the same time, if the evaporation method is used, there will be risks of red, blue and green plating on the back of the LED and plating on the front electrode of the LED. The light-emitting area affects the brightness; if it is plated to the electrode, it will cause difficult bonding of the light-emitting diode core, causing customer complaints; in order to solve the above problems, the present invention provides a high-efficiency and novel preparation method of DBR structure and its preparation led.

Contents of the invention

In view of the above problems, the present invention provides a method for preparing a light-emitting diode, which can avoid the problems caused by the traditional evaporation DBR preparation method, and at the same time can effectively increase the reflection of light and enhance the luminous efficiency of the light-emitting diode.

A method for preparing a light-emitting diode, comprising the following steps: (1) providing a growth substrate; (2) sequentially depositing a buffer layer, an N-type layer, a light-emitting layer, and a P-type layer on the growth substrate; N electrode and P electrode are prepared on the P-type layer and the P-type layer; (4) Grinding and thinning the back of the growth substrate; (5) Providing a Si substrate with the same diameter as the growth substrate; (6) Connecting the Si substrate to the growth substrate Alignment on the back of the substrate; (7) Bond the Si substrate on the back of the growth substrate through a bonding process, and then grind and thin it to form a thin layer of Si with a thickness of 10 to 1000 nm; (8) Align The thin layer of Si on the back of the growth substrate undergoes a thermal oxidation reaction to form a Si/SiO ₂ structure; (9) cycle steps (5) to (8) to form a DBR structure composed of n pairs of Si/SiO ₂ .

Preferably, the Si substrate in step (5) may be a Si-on-insulator substrate, and the steps (5) to (7) are changed to: (5) Provide a Si-on-insulator substrate with the same diameter as the growth substrate bottom, the upper surface of which is a thin layer of Si, and the thickness of the thin layer of Si is 10-1000 nm; (6) Align the upper surface of the Si-on-insulator substrate with the back of the growth substrate; (7) Through the stripping and bonding process, the The thin layer of Si on the upper surface of the Si-on-insulator substrate is bonded to the back of the growth substrate; other steps are the same.

Preferably, the diameters of the growth substrate, the Si substrate and the Si-on-insulator substrate are the same and ≥ 1 inch.

Preferably, the N-type layer is an N-type doped III-V group semiconductor layer, and the N-type dopant is preferably SiH ₄ .

Preferably, the light-emitting layer is a non-doped or N-type doped or P-type doped III-V semiconductor layer with a quantum well and/or quantum dot structure.

Preferably, the P-type layer is a P-type doped III-V group semiconductor layer, and the P-type dopant is preferably CP ₂ Mg.

Preferably, the thermal oxidation reaction is dry oxidation (reaction with O ₂ ) or wet oxidation (reaction with H ₂ O vapor) or a combination thereof, preferably dry oxidation, and the thermal oxidation reaction temperature is 500~1500°C .

Preferably, the logarithm of the DBR structure composed of Si/SiO ₂ is n≥2, preferably 2~4 pairs, wherein the thickness of Si is 5~500nm, and the thickness of SiO ₂ is 5~500nm.

The preparation method of the light-emitting diode of the present invention has at least the following beneficial effects:

(1) It can avoid the risk of red, blue and green back plating of LEDs and plating on the front electrodes of LEDs produced by the traditional evaporation DBR preparation method, thereby avoiding the impact on the yield and quality of LED chips;

(2) The number of layers is small and the interface is small, which has the advantages of good film formation and high reflectivity, which can effectively increase the reflection of light and enhance the luminous efficiency of light-emitting diodes.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In addition, the drawing data are descriptive summaries and are not drawn to scale.

1-2 are schematic flow charts for preparing light-emitting diodes in Example 1 of the present invention.

3-4 are schematic flow charts for preparing light-emitting diodes in Example 2 of the present invention.

Marked in the figure: 100: growth substrate; 101: buffer layer; 102: N-type layer; 103: light-emitting layer; 104: P-type layer; 105: N electrode; 106: P electrode; 107: insulating protection layer; 108: Si substrate; 109: Si-on-insulator substrate; 110: DBR structure.

detailed description

The specific implementation manners of the present invention will be described in detail below with reference to the drawings and examples.

Example 1

As shown in Figures 1-2, a schematic flow chart of a method for preparing a light-emitting diode, the method is realized by the following steps:

(1) Provide a growth substrate 100, the growth substrate is selected from Al ₂ O ₃ , SiC, Si, GaN, GaAs or GaP, and the diameter of the growth substrate is ≥ 1 inch;

(2) On the growth substrate 100, a buffer layer 101, an N-type layer 102, a light-emitting layer 103, and a P-type layer 104 are sequentially deposited, the buffer layer is a non-doped III-V semiconductor layer, and the N-type layer The layer is an N-type doped III-V semiconductor layer, the light-emitting layer is a non-doped or N-type doped or P-type doped III-V semiconductor layer with a quantum well and/or quantum dot structure, and the P The type layer is a P-type doped III-V semiconductor layer, the N-type dopant is preferably SiH ₄ , and the P-type dopant is preferably CP ₂ Mg;

(3) N-electrode 105 and P-electrode 106 are respectively prepared on N-type layer 102 and P-type layer 104, and N-electrode and P-electrode are selected from Au or Ag or Al or Pt or Ti or any combination thereof;

(4) Grinding and thinning the back of the growth substrate 100;

(5) providing a Si substrate 108 with the same diameter as the growth substrate 100;

(6) aligning the Si substrate 108 and the back side of the growth substrate 100;

(7) Bonding the Si substrate 108 to the back of the growth substrate 100 through a bonding process, and then grinding and thinning to form a thin layer of Si, the thickness of the thin layer of Si is 10-1000 nm;

(8) Perform thermal oxidation reaction on the thin layer of Si on the back of the growth substrate 100, choose dry oxidation (reaction with O ₂ ) or wet oxidation (reaction with H ₂ O vapor) or a combination thereof, preferably dry oxidation, so The thermal oxidation reaction temperature is 500~1500°C, forming a Si/ _SiO2 structure, wherein the thickness of Si is 5~500nm, and the thickness of _SiO2 is 5~500nm;

(9) Cycle steps (5) to (8) to form a DBR structure 110 composed of n pairs of Si/SiO ₂ , the logarithm n≥2, preferably 2 to 4 pairs;

(10) Forming an insulating protective layer 107 on the exposed epitaxial layer to protect the epitaxial layer, thus completing the preparation of the light emitting diode.

Example 2

As shown in Figures 3 to 4, the schematic flow chart of the preparation of light-emitting diodes in Example 2 differs from Example 1 in that the Si substrate 108 in step (5) of Example 1 is changed to a Si-on-insulator substrate 109, so Steps (5) to (7) of Embodiment 1 are changed to:

(5) Provide a Si-on-insulator substrate 109 having the same diameter as the growth substrate 100, the upper surface of which is a thin layer of Si, and the thickness of the thin layer of Si is 10-1000 nm;

(6) Aligning the upper surface of the Si-on-insulator substrate 109 with the back surface of the growth substrate 100;

(7) bonding the thin layer of Si on the upper surface of the Si-on-insulator substrate 109 to the back of the growth substrate 100 by a lift-off and bonding process;

Other preparation steps are identical with embodiment 1.

The light-emitting diode with a DBR structure composed of (Si/SiO ₂ ) _n prepared by the above method can avoid the risk of back-plating red, blue and green light-emitting diodes and plating on the front electrode of the light-emitting diode produced by the traditional evaporation DBR preparation method, thereby Avoiding the impact on the yield and quality of LED core particles; at the same time, the number of layers is small and the interface is small, which has the advantages of good film formation and high reflectivity, which can effectively increase the reflection of light and enhance the luminous efficiency of LEDs.

The foregoing represents preferred embodiments of the present invention, and it should be understood that those skilled in the art may modify the invention described herein while still achieving the advantageous effects of the present invention. Therefore, the above description should be understood as widely known to those skilled in the art, but not as a limitation to the present invention, and any changes made according to the present invention fall within the protection scope of the present invention.

Claims (10)

1. The preparation method of light-emitting diode, comprises following preparation steps: (1) Provide a growth substrate; (2) Deposit a buffer layer, an N-type layer, a light-emitting layer and a P-type layer sequentially on the growth substrate; (3) N-electrodes and P-electrodes are prepared on the N-type layer and the P-type layer respectively; (4) Grinding and thinning the back of the growth substrate; (5) Provide a Si substrate with the same diameter as the growth substrate; (6) Align the Si substrate with the back of the growth substrate; (7) Bond the Si substrate on the back of the growth substrate through a bonding process, and then grind and thin it to form a thin layer of Si with a thickness of 10 to 1000 nm; (8) Perform a thermal oxidation reaction on the thin layer of Si on the back of the growth substrate to form a Si/SiO ₂ structure; (9) Repeat steps (5) to (8) to form a DBR structure composed of n pairs of Si/SiO ₂ . 2. The method for manufacturing a light-emitting diode according to claim 1, wherein the Si substrate in the step (5) is a Si-on-insulator substrate, and the steps (5)-(7) are changed to: (5) Provide a Si-on-insulator substrate with the same diameter as the growth substrate, the upper surface of which is a thin layer of Si, and the thickness of the thin layer of Si is 10 to 1000nm; (6) Align the upper surface of the Si substrate on insulator with the back of the growth substrate; (7) Bonding the thin layer of Si on the upper surface of the Si-on-insulator substrate to the back of the growth substrate through a lift-off and bonding process; other preparation steps are the same as those described in claim 1. 3. The method of manufacturing a light emitting diode according to claim 1 or 2, characterized in that: the diameter of the growth substrate is ≥ 1 inch. 4. The method for manufacturing a light emitting diode according to claim 1, wherein the N-type layer is an N-type doped III-V group semiconductor layer. 5. The preparation method of light-emitting diode according to claim 1, characterized in that: the light-emitting layer is undoped or N-type doped or P-type doped III-V semiconductor layer quantum wells and/or quantum dots structure. 6 . The method for manufacturing a light emitting diode according to claim 1 , wherein the P-type layer is a P-type doped III-V group semiconductor layer. 7. The method for preparing a light emitting diode according to claim 1, characterized in that: the thermal oxidation reaction is dry oxidation or wet oxidation or a combination thereof. 8 . The method for preparing a light-emitting diode according to claim 7 , wherein the thermal oxidation reaction temperature is 500-1500° C. 9. The method for preparing a light-emitting diode according to claim 1, characterized in that: the logarithm of the DBR structure composed of Si/SiO ₂ is n≥2. 10. The method for preparing a light-emitting diode according to claim 1, characterized in that: the DBR structure composed of Si/SiO ₂ , wherein the thickness of Si is 5-500nm, and the thickness of SiO ₂ is 5-500nm.