KR101813891B1 - Light emitting diode - Google Patents

Abstract

The light emitting device according to the embodiment does not entirely etch a region where the electrode is to be formed but only a portion to which the auxiliary finger electrode is to be connected is partially etched, thereby reducing the area of the active layer exposed to the outside, The light efficiency is increased and the groove connecting the auxiliary finger electrode to the first semiconductor layer is separated from the electrode pad so that the light emitting device can be protected from ESD (Electrostatic Discharge).

Description

[0001]

The present invention relates to a light emitting device, and more particularly, to a light emitting device that protects a light emitting device from ESD (Electrostatic Discharge) and can improve light extraction efficiency.

Fluorescent lamps are gradually replacing with other light sources because of the frequent replacement of black spots and short life span and the use of fluorescent materials, which is against the trend of the future lighting market which is aiming for environment friendly.

As the other light source, LED (Light Emitting Diode) is one of the next generation light sources because of its high processing speed and low power consumption of semiconductors, as well as environment friendly and energy saving effect. Therefore, utilization of LEDs to replace conventional fluorescent lamps is actively underway.

Currently, semiconductor light emitting devices such as LEDs are applied to various apparatuses including televisions, monitors, notebooks, mobile phones, and other display devices, and are widely used as backlight units in place of conventional CCFLs.

Research is underway to improve the light extraction efficiency of the light emitting device, and the light emitting device is susceptible to ESD and research is underway to protect it from ESD.

In the embodiment, the light emitting device according to the embodiment does not entirely etch an area where an electrode is to be formed, but only a part to be connected with the auxiliary finger electrode is partially etched, thereby reducing the area of the active layer exposed to the outside, The light extraction efficiency and the light efficiency are increased.

Embodiments provide a light emitting device in which a finger electrode portion is formed symmetrically in a central portion of a light emitting element to improve a current diffusion effect.

A light emitting device according to an embodiment includes a substrate, a light emitting structure disposed on the substrate, the light emitting structure including a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer; A first electrode including a first electrode pad disposed on one side of the semiconductor layer and a first finger electrode portion connected to the first electrode pad and extending in the other direction; a first electrode formed between the second semiconductor layer and the first electrode, And a second electrode disposed on the other side of the second semiconductor layer, wherein the first electrode further includes at least one auxiliary finger electrode connected to the first finger electrode portion and connected to the first semiconductor layer And the light emitting structure includes a groove extending from the first finger electrode part to the first semiconductor layer and having a greater width than the auxiliary finger electrode.

Here, the first finger electrode unit may include a first finger electrode and a second finger electrode that is symmetric with the first finger electrode.

In addition, a plurality of the auxiliary finger electrodes may be formed, and the plurality of auxiliary finger electrodes may have the same interval between two adjacent auxiliary finger electrodes.

The present embodiment is not to entirely etch the region where the electrode of the light emitting device is to be formed but only the portion to which the auxiliary finger electrode is to be connected is partly etched so that the area of the active layer exposed to the outside is reduced and current leakage can be reduced, Is increased.

In addition, in the embodiment, the groove connecting the auxiliary finger electrode to the first semiconductor layer is spaced apart from the electrode pad, so that the light emitting element can be protected from ESD (Electrostatic Discharge).

1 is a layout diagram showing electrodes of a light emitting device according to an embodiment.
2 is a cross-sectional view taken along the line AA in Fig.
3 is a cross-sectional view taken along line BB in Fig.
4 is a view showing ESD destruction experiment data of the light emitting device.
5 is a diagram showing emission experiment data of the light emitting device.
6 is a layout view of an electrode of a light emitting device according to another embodiment.
7 is a cross-sectional view of a light emitting device package including the light emitting device according to the embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Thus, in some embodiments, well known process steps, well known device structures, and well-known techniques are not specifically described to avoid an undesirable interpretation of the present invention. Like reference numerals refer to like elements throughout the specification.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions. The elements can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Before the description of the embodiments, the terms "on", "below", or "above" the substrate, layer (film) region, electrode pad or patterns of each layer quot ;, " on ", "under ", " directly ", or " indirectly" In addition, the criteria for above or below each layer will be described with reference to the drawings.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size and area of each component do not entirely reflect actual size or area.

Further, the angle and direction mentioned in the description of the structure of the light emitting device in the embodiment are based on those shown in the drawings. In the description of the structure of the light emitting device in the specification, reference points and positional relationship with respect to angles are not explicitly referred to, refer to the related drawings.

1 is a cross-sectional view taken along the line AA of FIG. 1, FIG. 3 is a cross-sectional view taken along the line BB of FIG. 1, and FIG. FIG. 5 is a graph showing experimental data of ESD breakdown of a light emitting device. FIG.

1 to 3, a light emitting device 100 includes a substrate 110, a buffer layer 112, a first semiconductor layer 120, a second semiconductor layer 140, and first and second semiconductor layers 120, And 140 may include an active layer 130.

The substrate 110 is preferably formed using a transparent material including sapphire. In addition to sapphire, the substrate 110 may include zinc oxide (ZnO), gallium nitride (GaN) gallium nitride (GaN), silicon carbide (SiC), and aluminum nitride (AlN).

A buffer layer 112 may be disposed on the substrate 110 to mitigate lattice mismatch between the substrate 110 and the first semiconductor layer 120. The buffer layer 112 can be formed in a low-temperature atmosphere and can be selected from materials such as GaN, InN, AlN, AlInN, InGaN, AlGaN, and InAlGaN.

The first semiconductor layer 120 may be formed on the buffer layer 112. The first semiconductor layer 120 may include an n-type semiconductor layer to provide electrons to the active layer 130. The first semiconductor layer 120 may be formed of only the first conductive semiconductor layer, (Not shown) under the conductive type semiconductor layer, but the present invention is not limited thereto.

The n-type semiconductor layer may be a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? x? 1, 0? y? 1, 0? x + y? 1) , AlGaN, InGaN, InN, InAlGaN, AlInN and the like, and n-type dopants such as Si, Ge, and Sn can be doped.

The non-conductive semiconductor layer is a layer formed for improving the crystallinity of the first conductivity type semiconductor layer. The first conductivity type semiconductor layer has a lower electrical conductivity than that of the first conductivity type semiconductor layer because the n-type dopant is not doped. Type semiconductor layer.

Accordingly, the active layer 130 and the second semiconductor layer 140 may be sequentially stacked on the first semiconductor layer 120. [

First, the active layer 130 is a region where electrons and holes are recombined. As the electrons and the holes are recombined, the active layer 130 transits to a low energy level and can generate light having a wavelength corresponding thereto.

The active layer 130 includes a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) And may be formed of a single quantum well structure or a multi quantum well (MQW) structure. Therefore, more electrons are collected at the lower energy level of the quantum well layer, and as a result, the recombination probability of electrons and holes is increased, and the luminous efficiency can be improved. It may also include a quantum wire structure or a quantum dot structure.

A second semiconductor layer 140, and injects holes to the above-described active layer 130, a second There semiconductor layer 140 is, for example, be implemented as a p-type semiconductor layer, the semiconductor layer p is In _x Al _y Ga _{1-x y} N (For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, etc.) having a composition formula of 0? X? 1, 0? Y? 1, 0? X + A p-type dopant such as Mg, Zn, Ca, Sr, or Ba can be doped.

The first semiconductor layer 120, the active layer 130 and the second semiconductor layer 140 may be formed using a metal organic chemical vapor deposition (MOCVD) method, a chemical vapor deposition (CVD) method, A plasma enhanced chemical vapor deposition (PECVD), a molecular beam epitaxy (MBE), and a hydride vapor phase epitaxy (HVPE) It is not limited thereto.

In addition, the doping concentrations of the conductive dopants in the first semiconductor layer 120 and the second semiconductor layer 140 can be uniformly or nonuniformly formed. That is, the structure of the plurality of semiconductor layers may be variously formed, but the structure is not limited thereto.

In addition, unlike the above, the first semiconductor layer 120 may include a p-type semiconductor layer, and the second semiconductor layer 140 may include an n-type semiconductor layer. That is, the first semiconductor layer 120 and the second semiconductor layer 140 may be formed at different positions with respect to the active layer 130, but the first semiconductor layer 120 may include an n-type semiconductor layer And are stacked on the substrate 110. In this embodiment,

Referring again to FIG. 2, a light-transmitting electrode layer 150 may be formed on the second semiconductor layer 140.

The transparent electrode layer 150 is ITO, IZO (In-ZnO) , GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrO x, RuO x , RuO _x / ITO, Ni / IrO _x / Au, and Ni / IrO _x / Au / ITO. Accordingly, the light generated in the active layer 130 can be diverted to the outside, and the light can be prevented from being formed in the entire one or the entire outer surface of the second semiconductor layer 140, thereby preventing current clustering.

The first electrode 160 may be disposed on the second semiconductor layer 1400.

The first electrode 160 may include a first electrode pad 162 disposed on one side of the second semiconductor layer 140 and a first finger electrode portion 164 connected to the first electrode pad 162, 166).

The first electrode 160 may include a conductive material such as nickel, platinum, ruthenium, iridium, rhodium, tantalum, molybdenum, (Mo), titanium (Ti), silver (Ag), tungsten (W), copper (Cu), chromium (Cr), palladium (Pd), vanadium (V), cobalt (Co), niobium (Zr), indium tin oxide (ITO), aluminum zinc oxide (AZO), and indium zinc oxide (IZO). However, the present invention is not limited thereto.

An insulating layer 190 may be formed between the second semiconductor layer 140 and the first electrode 160 to prevent electrical short-circuiting.

The arrangement of the insulating layer 190 may be formed corresponding to the first electrode 160 and may be formed to have a width larger than the width of the first electrode 160, but is not limited thereto.

The insulating layer 190 comprises a nonconductive organic or inorganic material, preferably an organic material, for example, urethane, polyester or acrylic, and may also be a single layer, have. But it is natural that it is not limited thereto.

The first electrode 160 may further include at least one auxiliary finger electrode 168 connected to the first finger electrode unit 164 and 166 and connected to the first semiconductor layer 120. The auxiliary finger electrode 168 connected to the first finger electrode portions 164 and 166 penetrates the insulating layer 190, the second semiconductor layer 140 and the active layer 130 to form the first semiconductor layer 120 .

At this time, the first semiconductor layer 120 is extended from the first finger electrode parts 164 and 166 to the first semiconductor layer 120 to correspond to the auxiliary finger electrode 168, 180 may be formed. That is, a portion of the second semiconductor layer 140, the active layer 130, and the first semiconductor layer 120 formed between the auxiliary finger electrode 168 and the first semiconductor layer 120, Is formed.

The grooves 180 may be formed by wet etching, dry etching, or laser lift off (LLO), but are not limited thereto.

The size or shape of the groove 180 is not limited, but may preferably be greater than the width of the auxiliary finger electrode 168 to prevent electrical shorting.

If the first semiconductor layer 120 is an n-type semiconductor, the first electrode 160 operates as an n-type electrode.

The number of the auxiliary finger electrodes 168 is not limited and may be formed in a suitable number according to the size, area, and light emitting capacity of the light emitting device 100.

A plurality of auxiliary finger electrodes 168 may be formed and a plurality of auxiliary finger electrodes 168 may have the same interval d1 between two auxiliary finger electrodes 168 adjacent to each other. The intervals of the auxiliary finger electrodes 168 are the same so that the current diffusion can be uniformly performed throughout the light emitting element 100. [

In addition, a plurality of auxiliary finger electrodes 168 may be formed, and the distance between two adjacent auxiliary finger electrodes 168 may be closer to the first electrode pad 162. Therefore, even if the auxiliary finger electrode 168 is formed far from the first electrode pad 162, current supply can be smoothly performed.

The thickness of the auxiliary finger electrode 168 may become thicker as the distance from the first electrode pad 162 increases. Therefore, even if the auxiliary finger electrode 168 is formed far from the first electrode pad 162, current supply can be smoothly performed.

Embodiments can protect the light emitting device from electrostatic discharge (ESD) by supplying a current to the auxiliary finger electrode by performing a mesa etching on a portion spaced apart from the electrode pad, instead of supplying current from the electrode pad directly to the semiconductor layer. Referring to FIG. 4, in the ESD breakdown test of the prior art, 52% of the defect rate is shown, whereas in the embodiment, the defect rate is 84%, which is much improved ESD tolerance.

The insulating layer 190 may be formed between the first electrode 160 and the second semiconductor layer 140 and the first electrode 160 may be formed by etching the first electrode 160. [ Only a part of the light emitting device 100 is etched so that the auxiliary finger electrode 168 connected to the first and second semiconductor layers 160 and 164 can be connected to the first semiconductor layer 120. As a result, The current leakage is prevented, and the light extraction efficiency and the light efficiency are increased. Referring to FIG. 5, the emission experiment data shown in FIG. 5 shows that the emission area ratio of the prior art is 76%, while the embodiment has an effect of improving the emission area ratio by 79% to 3%.

1 to 3, the auxiliary finger electrode 168 and the inner surface of the groove 180 may be spaced apart from each other.

Therefore, electrical shorting between the auxiliary finger electrode 168 and the second semiconductor layer 140 and the active layer 130 can be prevented.

The insulating layer 190 may extend to surround the outer peripheral surface of the auxiliary finger electrode 168. That is, the insulating layer 190 may be formed in the space between the inner surface of the groove 180 and the auxiliary finger electrode 168. Therefore, electrical shorting can be prevented.

The number of the first finger electrode portions 164 and 166 is not limited, but may include a first finger electrode 164 and a second finger electrode 166. That is, the light emitting device 100 may be variously arranged according to the size of the light emitting device 100.

The first finger electrode 164 and the second finger electrode 166 may be disposed symmetrically with respect to each other. The first finger electrode 164 and the second finger electrode 166 are disposed symmetrically with respect to each other, so that efficient current diffusion can be expected.

In addition, at least one of the first finger electrode 164 and the second finger electrode 166 may include a bend. The bending can be arranged in various forms in consideration of the shape of the light emitting device 100 and current diffusion. The bending may have a curvature, but is not limited thereto.

The second semiconductor layer 140 may include a second electrode 170.

The second electrode 170 is connected to the second electrode pad 172 and the second electrode pad 172 disposed on one side of the second semiconductor layer and includes at least one second Finger electrode portions 174, 176, and 178, respectively.

At least one of the second finger electrode units 174, 176, and 178 may be disposed, and the number of the second finger electrode units 174, 176, and 178 is not limited. Preferably, the third finger electrode 174, 176 and a fifth finger electrode 178. That is, the light emitting device 100 may be variously arranged in consideration of current diffusion according to the size of the light emitting device 100.

The third finger electrode 174 is disposed between the first finger electrode 164 and the second finger electrode 166 and spaced apart from the first finger electrode 164 and the second finger electrode 166 by a predetermined distance . The distance d2 between the first finger electrode 164 and the third finger electrode 174 may be the same as the separation distance d3 between the second finger electrode 166 and the third finger electrode 174. [ This is because the fingers are symmetrical with respect to the third finger electrode 174 to improve the current diffusion effect. The distance d2 between the first finger electrode 164 and the third finger electrode 174 may be different from the distance d3 between the second finger electrode 166 and the third finger electrode 174 . But is not limited thereto.

The fourth finger electrode 176 and the fifth finger electrode 178 may be disposed symmetrically with respect to the third finger electrode 174. The fourth finger electrode 176 and the fifth finger electrode 178 may be spaced apart from the first finger electrode 164 and the second finger electrode 166 by a predetermined distance.

The distance between the third finger electrode 174 and the fourth finger electrode 176 may be the same as the distance between the third finger electrode 174 and the fifth finger electrode 178, but is not limited thereto.

The separation distance d4 between the first finger electrode 164 and the fourth finger electrode 176 may be different from the separation distance d5 between the first finger electrode 164 and the fifth finger electrode 178 Can be arranged identically.

That is, the distances between the fingers are constant and are symmetrically arranged to improve the current diffusion effect.

At least one of the third finger electrode 174 to the fifth finger electrode 178 includes a bend, and the bend may be formed to have a curvature.

6 is a layout view of an electrode of a light emitting device according to another embodiment. Referring to FIG. 6, the light emitting device 200 of the embodiment is different from the light emitting device 100 of the other embodiment only in the arrangement of the fingers, and the other components are the same.

The light emitting device 200 includes a first finger electrode unit 264 disposed at the center of the light emitting device 200 and two second finger electrode units 274 symmetrical with respect to the first finger electrode unit 264 , 276 are disposed. The embodiment is merely an example in which the arrangement of the fingers can be changed according to the size of the light emitting device 200, but the fingers can be arranged in various ways without being limited thereto.

Although the horizontal emitting type light emitting device is described as an example in the embodiment, the present invention is not limited thereto, and may be applied to a vertical type light emitting device, a flip type light emitting device, or a light emitting device having a via hole structure.

7 is a cross-sectional view of a light emitting device package including the light emitting device according to the embodiment.

7, the light emitting device package 300 includes a body 320, a first electrode layer 331 and a second electrode layer 332 provided on the body 320, A light emitting device 350 according to an embodiment electrically connected to the first electrode layer 331 and the second electrode layer 332 and a molding member 340 sealing the light emitting device 350.

The body 320 may be formed of a silicon material, a synthetic resin material, or a metal material, and an inclined surface may be formed around the light emitting device 350.

The first electrode layer 331 and the second electrode layer 332 are electrically isolated from each other and provide power to the light emitting device 350. The first electrode layer 331 and the second electrode layer 332 may reflect the light generated by the light emitting device 350 to increase the light efficiency and may be configured to discharge heat generated from the light emitting device 350 to the outside It can also play a role.

The light emitting device 350 may be mounted on the body 320 or on the first electrode layer 331 or the second electrode layer 332.

The light emitting device 350 may be electrically connected to the first electrode layer 331 and the second electrode layer 332 by a wire, flip chip, or die bonding method.

The molding member 340 can protect the light emitting device 350 by sealing. In addition, the molding member 340 may include a phosphor to change the wavelength of the light emitted from the light emitting device 350.

At least one of the light emitting devices of the above-described embodiments may be mounted on one or more than one light emitting device package, but the present invention is not limited thereto.

A light guide plate, a prism sheet, a diffusion sheet, and the like, which are optical members, may be disposed on the light path of the light emitting device package. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Still another embodiment may be implemented as a display device, an indicating device, and a lighting system including the light emitting device or the light emitting device package described in the above embodiments. For example, the lighting system may include a lamp and a streetlight.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

100: light emitting device 110: substrate
112: buffer layer 120: first semiconductor layer
130: active layer 140: second semiconductor layer
150: Transparent electrode layer 160: First electrode
162: first electrode pad 164: first finger electrode
166: second finger electrode 168: auxiliary finger electrode
170: second electrode 172: second electrode pad
174: Third finger electrode 176: Fourth finger electrode
178: fifth finger electrode 180: groove
190: insulating layer

Claims (15)

Board;
A light emitting structure disposed on the substrate and including a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer;
A first electrode including a first electrode pad disposed on one side of the second semiconductor layer and a first finger electrode portion connected to the first electrode pad and extending in the other direction;
An insulating layer formed between the second semiconductor layer and the first electrode; And
And a second electrode disposed on the other side of the second semiconductor layer,
Wherein the first electrode further comprises at least one auxiliary finger electrode connected to the first finger electrode portion and connected to the first semiconductor layer,
Wherein the light emitting structure includes a groove extending from the first finger electrode portion to the first semiconductor layer and having a width larger than that of the auxiliary finger electrode,
Wherein the first finger electrode portion includes:
A first finger electrode; And
And a second finger electrode symmetrical with the first finger electrode,
Wherein a distance between the first finger electrode and the second finger electrode is the same,
The groove
A plurality of first finger electrodes and second finger electrodes are formed at equal intervals,
Wherein the auxiliary finger electrode comprises:
Wherein a distance between two adjacent auxiliary finger electrodes is closer to the first electrode pad, and a thickness of the auxiliary finger electrode increases as the distance from the first electrode pad increases. The method according to claim 1,
Wherein the auxiliary finger electrode comprises:
A plurality of electrodes are formed,
Wherein the plurality of auxiliary finger electrodes are spaced apart from each other by two auxiliary finger electrodes adjacent to each other. The method according to claim 1,
Wherein the auxiliary finger electrode comprises:
And is spaced apart from an inner surface of the groove. The method according to claim 1,
Wherein the insulating layer
And a space between the auxiliary finger electrode and the inner surface of the groove. The method according to claim 1,
The second electrode,
And a second finger electrode part connected to the second electrode pad and extending in the first electrode pad direction. 6. The method of claim 5,
The second finger electrode unit
A third finger electrode disposed between the first and second finger electrodes; And
And a fourth finger electrode and a fifth finger electrode disposed apart from the first and second finger electrodes by a predetermined distance. The method according to claim 6,
And at least one of the first to fifth finger electrodes has a curvature. The method according to claim 6,
And the groove is symmetrically arranged with respect to the third finger electrode. The method according to claim 6,
Wherein a distance between the first finger electrode and the third finger electrode is equal to a distance between the second finger electrode and the third finger electrode. The method according to claim 6,
Wherein a distance between the first finger electrode and the fourth finger electrode is equal to a distance between the second finger electrode and the fifth finger electrode. The method according to claim 6,
And a distance between the third finger electrode and the fourth finger electrode is equal to a distance between the third finger electrode and the fifth finger electrode. 8. The method of claim 7,
Wherein the fourth finger electrode and the fifth finger electrode are disposed symmetrically with respect to the third finger electrode. A light emitting device package comprising the light emitting device according to any one of claims 1 to 12. delete delete

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