KR101241533B1

KR101241533B1 - Light emitting diode and method for manufacturing led

Info

Publication number: KR101241533B1
Application number: KR1020040075980A
Authority: KR
Inventors: 최성철
Original assignee: 엘지이노텍 주식회사
Priority date: 2004-09-22
Filing date: 2004-09-22
Publication date: 2013-03-08
Also published as: KR20060027134A

Abstract

The present invention discloses a light emitting diode and a method of manufacturing the same, which increase the light efficiency by lowering the vertical current density by increasing the area of the active layer. The disclosed invention comprises the steps of forming a nitride semiconductor layer; Forming a first nitride semiconductor layer having a surface of an uneven structure on the nitride semiconductor layer according to an etching pattern formed by a photo process; Forming an active layer having an uneven structure on the first nitride semiconductor layer having the uneven structure; And forming a second nitride semiconductor layer on the active layer having the uneven structure.

Light emitting diode, active layer, gallium layer, area, current density, light efficiency

Description

LIGHT EMITTING DIODE AND METHOD FOR MANUFACTURING LED}

1 is a view for explaining the structure and manufacturing process of a semiconductor light emitting device according to the prior art.

2 is a view showing the structure of a semiconductor light emitting device according to the present invention.

3 is a diagram illustrating the structure of a semiconductor light emitting device according to another embodiment of the present invention;

Description of the Related Art [0002]

100: sapphire substrate 111: buffer layer

113: Undoped GaN layer 114: N-type GaN layer

115: active layer 116: P-type AlGaN (Mg) layer

117: P-type GaN layer

The present invention relates to a light emitting diode, and more particularly, to a light emitting diode and a method for manufacturing the same, which lower the vertical current density to improve light efficiency.

In general, a light emitting diode (LED) is a type of semiconductor used to send and receive signals by converting electricity into infrared rays or light using characteristics of a compound semiconductor. It is used for various automation equipment.

The operation principle of the LED is that when a forward voltage is applied to a semiconductor of a specific element, electrons and holes move and recombine with each other through a junction portion of a positive-negative and a positive-negative, and energy levels are caused by the combination of electrons and holes. Will fall and this energy level is emitted as light.

In addition, LEDs are generally manufactured in small sizes and have structures mounted on epoxy molds, lead frames, and PCBs. Currently, the most commonly used LEDs are 5mm (T 1 3/4) plastic packages or new types of packages depending on the specific application. The color of the light emitted by the LED creates a wavelength depending on the composition of the semiconductor chip components, and the wavelength determines the color of the light.

In particular, LEDs are becoming smaller and smaller, such as resistors, capacitors, and noise filters, due to the trend toward miniaturization and slimming of information and communication devices, and directly mounting them on a PCB (Printed Circuit Board) board. In order to make the surface mount device (Surface Mount Device) type.

Accordingly, LED lamps, which are used as display elements, are also being developed in SMD type. Such SMD can replace the existing simple lighting lamp, which is used for lighting indicators of various colors, character display and image display.

As shown in FIG. 1, a buffer layer made of gallium nitride (GaN) is formed on a sapphire substrate 10 composed of an Al ₂ O ₃ series component. Then, an undoped GaN layer 3 is successively grown on the buffer layer 1.

As described above, in order to grow a thin film of the Group 3 series element on the sapphire substrate 10, a metal organic chemical vapor deposition (MOCVD) is generally used, and the growth pressure is 200 torr (torr). Form a layer while maintaining 650 torr.

An N-type GaN layer 5 is formed on the undoped GaN layer 3, in order to form the silicon using silicon tetrahydride (Si: H4) or silicon dihydride (Si ₂ H ₆ ) gas. This is used.

When the N-type gallium nitride layer (GaN: 5) is grown, an active layer 7 is grown on the N-type gallium nitride layer 5. The active layer 7 is a semiconductor layer to which a light emitting material made of indium gallium nitride (InGaN) is added as a light emitting region. As the active layer 7 is grown, a P-type AlGaN (Mg) layer 9 is subsequently formed. In the P-type AlGaN (Mg) layer 7, Mg-based Group 2 elements are used.

The P-type AlGaN (Mg) layer 7 is contrasted with the N-type gallium nitride layer 5, and the N-type gallium nitride layer 5 transfers electrons to the active layer 7 by a voltage applied from the outside. Supply.

In addition, the P-type AlGaN (Mg) layer 9 supplies holes to the active layer 7 by a voltage applied to the outside, whereby holes and electrons in the active layer 7 To generate light.

Then, a contact layer (not shown) made of P-type GaN is grown on the P-type AlGaN (Mg) layer 9 for electrical contact with a P-type electrode (not shown).

And the contact layer, the P-type AlGaN (Mg) layer 9, the active layer 7, and the N-type GaN layer 5 for electrical contact between the N-type electrode (not shown) and the Un-GaN layer 3. An edge region is etched to expose the Un-GaN layer 3.

Then, an N-type electrode is formed on the exposed Un-GaN layer 3, and a P-type electrode is formed on the contact layer.

However, in order to improve the productivity of the semiconductor light emitting device having the above structure, a larger number of semiconductor light emitting devices should be formed on a single wafer. As the number of semiconductor light emitting devices increases, the chip area of the light emitting devices is inevitably small. You lose.

As described above, when the chip area of the light emitting device is reduced, the vertical current density increases, and the increase in the vertical current density causes a deterioration and a decrease in reliability.

In particular, deterioration and reliability deterioration of the semiconductor light emitting device reduce light brightness and increase leakage current.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting diode and a method of manufacturing the light emitting diode having improved light efficiency by lowering the vertical current density by forming an active layer of a semiconductor light emitting device in an uneven structure.

A light emitting diode manufacturing method according to the present invention for achieving the above object,

Forming a nitride semiconductor layer;

Forming a first nitride semiconductor layer having a surface of an uneven structure on the nitride semiconductor layer according to an etching pattern formed by a photo process;

Forming an active layer having an uneven structure on the first nitride semiconductor layer having the uneven structure; And

And forming a second nitride semiconductor layer on the active layer having the uneven structure.

In addition, the light emitting diode manufacturing method according to the present invention,

Forming a nitride semiconductor layer;

Forming a first nitride semiconductor layer having a surface of an uneven structure according to an etching pattern formed by a photo process on the gallium nitride layer;

Forming a first active layer having an uneven structure on the first nitride semiconductor layer having the uneven structure;

Repeating the above steps to alternately form a nitride semiconductor layer and an active layer having a plurality of uneven structures; And

And forming a second nitride semiconductor layer on the alternately formed top active layer.

Here, the nitride semiconductor layer and the active layer having the uneven structure are each characterized by three or more.

The light emitting diode according to the present invention,

Board;

A first nitride semiconductor layer having a concave-convex structure on the substrate;

An active layer having an uneven structure formed on the first nitride semiconductor layer; And

And a second nitride semiconductor layer formed on the active layer.

In addition, the light emitting diode according to the present invention,

Board;

A plurality of active layers having an uneven structure on the first nitride semiconductor layer; And

And a second nitride semiconductor layer formed on the plurality of active layers.

Here, the nitride semiconductor layer and the active layer having the concave-convex structure are three or more, respectively, and the third nitride semiconductor layer is further formed on the second nitride semiconductor layer.

According to the present invention, the active layer of the semiconductor light emitting device has a concave-convex structure to lower the vertical current density to improve the light efficiency.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, a GaN buffer layer 111 formed of gallium nitride (GaN) is formed on the sapphire substrate 100 having Al ₂ O ₃ based components.

Thereafter, an undoped GaN layer 113 is grown on the buffer layer 111.

An N-type GaN layer 114 is formed on the undoped GaN layer 113. To form the same, silicon using silicon tetrahydride (Si: H4) or silicon dihydrogen (Si ₂ H ₆ ) gas is formed. This is used.

When the N-type gallium nitride layer (GaN) 114 is grown, a photoresist is coated on the N-type gallium nitride layer 114, and then an exposure process is performed using a mask.

When the exposure process is performed, it is developed to form an etching pattern.

When the etching pattern is formed on the N-type gallium nitride layer 114 according to the photo process as described above, an etching process is performed to form an uneven structure on the surface of the N-type gallium nitride layer 114.

The uneven structure is for maximizing the surface area of the N-type gallium nitride layer 114, so the number of peaks and valleys is better.

As described above, when the N-type gallium nitride layer 114 having an uneven structure is formed by the etching process, the active layer 115 including the InGaN component is grown on the N-type gallium nitride layer.

Since the active layer 115 is grown along the uneven structure of the N-type gallium nitride layer 114, the active layer 115 is formed in the same shape as the uneven structure formed on the N-type gallium nitride layer 114.

Therefore, the surface area of the active layer 115 also increases.

When the active layer 115 is formed, a P-type AlGaN (Mg) layer 116 is subsequently formed.

Mg-based Group 2 elements are used for the P-type AlGaN (Mg) layer 116.

The P-type GaN layer 117 is grown on the P-type AlGaN (Mg) layer 116 for electrical contact with the second electrode to be formed later, and the first electrode and the Un-GaN layer 113 The un-GaN layer 113 is etched by etching edge regions of the P-type GaN layer 117, the P-type AlGaN (Mg) layer 116, the active layer 115, and the N-type GaN layer 114 for electrical contact. To be exposed.

Here, the second N-type GaN layer may be further grown on the P-type GaN layer.

Then, a first electrode is formed on the exposed Un-GaN layer 113, and a second electrode is formed on the P-type GaN layer 117.

Therefore, by reducing the chip area of the light emitting device, the increased vertical current density is lowered by the active layer 115 having the uneven structure, thereby increasing the light efficiency.

In addition, when the vertical current density decreases due to an increase in the area of the active layer 115, the degradation phenomenon is reduced accordingly.

3 is a diagram illustrating a structure of a semiconductor light emitting device according to another exemplary embodiment of the present invention.

As shown in FIG. 3, a buffer layer (GaN buffer layer) 111 and an undoped GaN layer 113 are successively formed on the sapphire substrate 100 composed of Al ₂ O ₃ series components. .

Then, a first N-type GaN layer 114a is formed on the undoped GaN layer 113.

Then, the first N-type GaN layer 114a is formed in an uneven structure according to the etching process described with reference to FIG. 2. Then, a first active layer 115a made of InGaN component is grown on the first N-type GaN layer 114a.

The first active layer 115a has a concave-convex structure according to the concave-convex structure of the first N-type GaN layer 114a.

The above process is repeated to form a second N-type GaN layer 114b on the first active layer 115a, and then the second active layer 115b is formed on the second N-type GaN layer 114a. Form.

A third N-type GaN layer 114c is formed on the second active layer 115b, and a third active layer 115c is formed on the third N-type GaN layer 114c.

Therefore, the first active layer 115a, the second active layer 115b, and the third active layer 115c all have an uneven structure.

As such, a plurality of active layers 115: 115a, 115b, and 115c are formed between the N-type GaN layers 114 to enlarge the area of the active layer 115.

In the drawing, three active layers 115 are formed, but in some cases, three or more active layers may be formed.

Mg-based Group 2 elements are used for the P-type AlGaN (Mg) layer 116.

The P-type GaN layer 117 is grown on the P-type AlGaN (Mg) layer 116 for electrical contact with the second electrode 120 to be formed later, and the first electrode 130 and the Un-GaN In order to make electrical contact with the layer 113, the regions of the P-type GaN layer 117, the P-type AlGaN (Mg) layer 116, the active layer 115, and the N-type GaN layer 114 are partially etched. The GaN layer 113 is exposed.

Here, the fourth N-type GaN type may be further grown on the P-type GaN layer.

As described in detail above, the present invention improves the light efficiency by forming the active layer of the semiconductor light emitting device having an uneven structure to lower the vertical current density.

The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art without departing from the gist of the present invention as claimed in the following claims.

Claims

delete

Forming a nitride semiconductor layer;

Forming a second nitride semiconductor layer having an uneven structure on the first active layer and having the same polarity as the first nitride semiconductor layer;

Forming a second active layer having an uneven structure on the second nitride semiconductor layer having the uneven structure;

Forming a third nitride semiconductor layer having a different polarity from the first nitride semiconductor layer on the second active layer; Light emitting diode manufacturing method comprising a.

The method of claim 2,

And forming a fourth nitride semiconductor layer having the same polarity as the first nitride semiconductor layer on the third nitride semiconductor layer.

delete

Board;

A first active layer having a concave-convex structure on the first nitride semiconductor layer;

A second nitride semiconductor layer having an uneven structure on the first active layer and having the same polarity as the first nitride semiconductor layer;

A second active layer having an uneven structure on the second nitride semiconductor layer having the uneven structure;

A third nitride semiconductor layer having a different polarity from the first nitride semiconductor layer on the second active layer;

Light emitting diode comprising a.

6. The method of claim 5,

And a fourth nitride semiconductor layer having the same polarity as the first nitride semiconductor layer on the third nitride semiconductor layer.

delete