CN102208504A - Quaternary light emitting diode and preparation method thereof - Google Patents

Abstract

The invention discloses a quaternary light emitting diode and a preparation method thereof, relating to a semiconductor light emitting diode and a preparation method thereof and belonging to the semiconductor photoelectron technology field. From the bottom up the quaternary light emitting diode comprises a substrate 1, a buffer layer 2, a Bragg reflector 3, a lower coating 4, an active layer 5, an upper coating 6, a current barrier layer 7 which is formed at a relative position to an electrode 9, an epitaxial window layer 8 which grows at the surface of the current barrier layer 7, and the electrode 9 which is installed on the current barrier layer, wherein the Bragg reflector is a layer containing alumina whose reflection coefficient is higher than the reflection coefficient of a layer containing aluminium. According to the invention, a current barrier region corresponding with the electrode is made at the surface of the epitaxial layer, brightness loss is minimized, combined with wet oxidation technology to optimize the epitaxial layer material property, the light extraction efficiency is greatly raised, thereby a composite brightness enhancement light emitting diode with an optimized structure is obtained.

Description

A kind of four-element LED and preparation method thereof

Technical field

The invention discloses a kind of four-element LED, relate to a kind of semiconductor light-emitting-diode, aim to provide a kind of light-emitting diode structure that increases luminous efficiency and preparation method thereof, belong to field of semiconductor photoelectron technique.

Background technology

Light-emitting diode (LED, light emitting diode) be by the III-IV compounds of group, make as GaAs (GaAs), GaP (gallium phosphide), GaAsP semiconductors such as (gallium arsenide phosphides), have the forward conduction of general P-N knot, oppositely by, breakdown characteristics.Under forward voltage, electronics injects the P district by the N district, and the N district is injected by the P district in the hole.Minority carrier (few son) part that enters the other side zone is compound and luminous with majority carrier (many sons).

Because the light absorptive of quaternary system reddish yellow light-emitting diode material itself is stronger, especially the gallium arsenide substrate absorption effects is obvious, so the light-emitting diode light extraction efficiency of ordinary construction is lower.Simultaneously, common electrode of light emitting diode structure is owing to the design feature of itself, and one part of current can cause the efficient lighting area loss from electrode below process.Therefore, because the influence of above two aspect factors, the external quantum efficiency of the light-emitting diode of ordinary construction is lower.

At above two aspect problems, the someone has proposed DBR (Bragg reflection) blast technology and current blocking technology respectively.But because the limitation of every technology, the effect that improves light extraction efficiency is more limited, and the cost that has is higher, is unfavorable for large-scale production.How integrated use number of ways increases substantially the light extraction efficiency of light-emitting diode, and being needs the problem that solves at present.

Summary of the invention

Below the electrode that the electric current of light-emitting diode injects, make current barrier layer, can make most of electric current flow through active area by the current extending around the electrode, avoided the crowded of electrode below electric current like this, but because the photon that this part electric current produces since electrode stop with body in absorb, and can not be transmitted into external, produce a large amount of heat in vivo, lowered device performance greatly.Light absorptive owing to quaternary system reddish yellow light-emitting diode material itself is stronger simultaneously, so the light-emitting diode light extraction efficiency of ordinary construction is lower, in order to address the above problem, the present invention proposes a kind of four-element LED and preparation method thereof.

A kind of four-element LED, comprise from bottom to top substrate 1, resilient coating 2, Bragg reflector 3, time coating layer 4, active layer 5, last coating layer 6, it is characterized in that: be manufactured with current barrier layer 7 in last coating layer 6 position relative with electrode, superficial growth at current barrier layer 7 has extension Window layer 8, and electrode 9 is installed on the current barrier layer 7; The edge of described Bragg reflector 3 is the reflection coefficient salic layer high than aluminous layer.

The material of current barrier layer 7 is the insulated non-metal material.

The manufacture method of described a kind of four-element LED comprises the following step:

A. extension is grown for the first time, finishes epitaxial loayer basic structure: begin to be followed successively by substrate 1, resilient coating 2, Bragg reflector 3, following coating layer 4, active layer 5 and last coating layer 6 by the bottom; As shown in Figure 1.

B. make current barrier layer 7: this barrier layer is by deposition, photoetching and etching technics, and the position relative with electrode at epitaxial surface makes current barrier layer 7;

C. extension is grown for the second time: in current barrier layer 7 superficial growth extension Window layer 8, form complete epitaxial structure, finish the preparation of extension;

D. make and current barrier layer 7 phase position electrode of opposite 9 at epitaxial surface; As shown in Figure 2.

E. the edge to the Bragg reflector in the epitaxial loayer carries out oxidation: the edge of the aluminous layer of Bragg reflector is oxidized to salic layer, improves the reflection coefficient of this layer;

F. grind the attenuate substrate, by metal coating in substrate bottom deposited metal;

G. extension is cut into individual chips.

Above-mentioned current barrier layer 7 is by what photoetching, etching process to epitaxial loayer itself formed electric current to be had the epitaxial surface of blocking effect.

The manufacture method of above-mentioned four-element LED comprises the mode of oxidizing of wet nitrogen or wet oxygen for the method for oxidation of Bragg reflector 7.

The making of above-mentioned Window layer 8 is the growth second time of extension, at current barrier layer 7 superficial growth extension GaP layers.

The present invention can obtain following beneficial effect, a kind of four-element LED utmost point has been proposed, it is a kind of NEW TYPE OF COMPOSITE blast light-emitting diode of optimizing structure, optimize structure to be not only and below electrode, make current barrier layer, allow electric current around electrode, flow through, reduced luminous loss, and improved epitaxial structure by the mode of oxidation, improve the reflection efficiency of Bragg reflector layer, both composite actions make the light extraction efficiency of light-emitting diode obtain increasing substantially.

The composite action of the two above two kinds of methods is applied in the middle of LED device makes simultaneously, owing to can make the luminous efficiency of device promote more than one times.

Description of drawings

Fig. 1 is the epitaxial structure schematic diagram of common epitaxial wafer;

Fig. 2 is for increasing the epitaxial structure schematic diagram of current barrier layer;

Fig. 3 is the structural representation of a kind of four-element LED disclosed by the invention.

Fig. 4 is the making flow chart of a kind of four-element LED disclosed by the invention.

Among the figure: 1, substrate, 2, resilient coating, 3, Bragg reflector, 4, coating layer down, 5, active layer, 6, go up coating layer, 7, current barrier layer, 8, Window layer, 9, electrode, 10 oxide layers

Embodiment

Be described further for the present invention below in conjunction with the drawings and specific embodiments:

As shown in Figure 3, a kind of four-element LED, comprise from bottom to top substrate 1, resilient coating 2, Bragg reflector 3, time coating layer 4, active layer 5, last coating layer 6, it is characterized in that: be manufactured with current barrier layer 7 in last coating layer 6 position relative with electrode, superficial growth at current barrier layer 7 has extension Window layer 8, and electrode 9 is installed on the current barrier layer; Described Bragg reflector 7 is the reflection coefficient salic layer high than aluminous layer.

The material of current barrier layer 7 is the insulated non-metal material.

The manufacture method of described a kind of four-element LED comprises the following step as shown in Figure 4:

A. extension is grown for the first time, finishes extension basic structure: begin to be followed successively by substrate 1, resilient coating 2, Bragg reflector 3, following coating layer 4, active layer 5 and last coating layer 6 by the bottom, as shown in Figure 1;

B. make current barrier layer 7: this barrier layer is by deposition, photoetching and etching technics, and the position relative with electrode at epitaxial surface makes current barrier layer 7;

C. extension is grown for the second time: in current barrier layer 7 superficial growth extension Window layer 8, form complete epitaxial structure, finish the preparation of extension;

D. make and current barrier layer 7 phase position electrode of opposite 9 at epitaxial surface, as Fig. 2;

E. to the edge oxidation of the Bragg reflector in the epitaxial loayer: the aluminous layer of Bragg reflector is oxidized to salic layer, improves the reflection coefficient of this layer;

F. grind the attenuate substrate, by metal coating in substrate bottom deposited metal;

G. extension is cut into individual chips.

Described current barrier layer 7 is by what photoetching, etching process to epitaxial loayer itself formed electric current to be had the manufacture method of the four-element LED that the epitaxial surface of blocking effect states, and comprises the mode of oxidizing of wet nitrogen or wet oxygen for the method for oxidation of Bragg reflector 7.

The making of above-mentioned Window layer 8 is the growth second time of extension, at current barrier layer 7 superficial growth extension GaP layers.

As mentioned above, the invention provides a kind of NEW TYPE OF COMPOSITE blast light-emitting diode structure and manufacture method thereof of optimizing structure, so offer the application of patent of invention in accordance with the law, yet, above implementation is preferred embodiment of the present invention, is not to limit to the present invention with this, be with, such as be similar to, duplicate with structure of the present invention, device, feature etc., all should belong to of the present invention founding within purpose and the claim.

Claims (5)

1. four-element LED, comprise from bottom to top substrate (1), resilient coating (2), Bragg reflector (3), time coating layer (4), active layer (5), last coating layer (6), it is characterized in that: be manufactured with current barrier layer (7) in last coating layer (6) position relative with electrode, superficial growth at current barrier layer (7) has extension Window layer (8), and electrode (9) is installed on the current barrier layer; The edge of described Bragg reflector (7) is salic layer.

2. a kind of four-element LED according to claim 1 is characterized in that: the material of current barrier layer (7) is the insulated non-metal material.

3. four-element LED according to claim 1 is characterized in that: described current barrier layer (7) is by what photoetching, etching process to epitaxial loayer itself formed electric current to be had the epitaxial surface of blocking effect.

4. the manufacture method of the described a kind of four-element LED of claim 1 is characterized in that: comprise the following step:

A. extension is grown for the first time, finishes extension basic structure: begin to be followed successively by substrate (1), resilient coating (2), Bragg reflector (3), following coating layer (4), active layer (5) and last coating layer (6) by the bottom;

B. make current barrier layer (7): this barrier layer is by deposition, photoetching and etching technics, and the position relative with electrode at epitaxial surface makes current barrier layer (7);

C. extension is grown for the second time: in current barrier layer (7) superficial growth extension Window layer (8), form complete epitaxial structure, finish the preparation of extension;

D. make and current barrier layer (7) phase position electrode of opposite (9) at epitaxial surface;

E. to the Bragg reflector oxidation in the epitaxial loayer: the edge of the aluminous layer of Bragg reflector is oxidized to salic layer, improves the reflection coefficient of this layer;

F. grind the attenuate substrate, by metal coating in substrate bottom deposited metal;

G. extension is cut into individual chips.

5. the manufacture method of four-element LED as claimed in claim 4 is characterized in that: the mode of oxidizing that comprises wet nitrogen or wet oxygen for the method for oxidation of Bragg reflector (7).

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