KR20170082714A - Light emitting device and light emitting device module including the same - Google Patents

Abstract

A light emitting structure including a first conductivity type semiconductor layer, an active layer on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer on the active layer; A first electrode disposed on at least a part of a side surface of the first conductivity type semiconductor layer; And a second electrode disposed on the second conductivity type semiconductor layer and including a penetrating electrode passing through the light emitting structure and a branch electrode disposed on the second conductivity type semiconductor layer, The penetrating electrode provides a light emitting element exposed to a lower region of the light emitting structure.

Description

TECHNICAL FIELD [0001] The present invention relates to a light emitting device and a light emitting device array module including the light emitting device.

The present invention relates to a light emitting device and a light emitting device array module including the light emitting device. More particularly, the present invention relates to a light emitting device having excellent heat dissipation characteristics and uniformly injecting current into the entire region of the light emitting structure, and a light emitting device array module .

GaN, and AlGaN are widely used for optoelectronics and electronic devices due to their advantages such as wide and easy bandgap energy.

Particularly, a light emitting device such as a light emitting diode or a laser diode using a semiconductor material of a 3-5 group or a 2-6 group compound semiconductor has been widely used in various fields such as red, green, blue and ultraviolet rays It can realize various colors, and it can realize efficient white light by using fluorescent material or color combination. It has low power consumption, semi-permanent lifetime, fast response speed, safety, and environment compared to conventional light sources such as fluorescent lamps and incandescent lamps Affinity.

Therefore, a transmission module of the optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a white light emitting element capable of replacing a fluorescent lamp or an incandescent lamp Diode lighting, automotive headlights, and traffic lights.

In a conventional light emitting device, a light emitting structure including an n-type semiconductor layer, an active layer and a p-type semiconductor layer is formed, and electrons injected through the n-type semiconductor layer and holes injected through the p- Emits light with energy determined by the material's inherent energy band.

There is an attempt to reduce the cross sectional area of the light emitting structure to form pixels. However, since the thickness of each light emitting structure is too large, it is difficult to realize a unit pixel of a unit thin type.

That is, the above-described light emitting structure is grown on a substrate such as sapphire. The light emitting structure is a vertical type light emitting device in which a substrate remains after growth of a light emitting structure, a vertical type In the case of a light emitting device or the like, it is difficult to form an ultra-thin pixel because the thickness of the substrate or the metal support is large.

Further, when forming a thin-film pixel with a light-emitting element, there is a problem of a method of uniformly supplying current when a substrate or a supporting substrate is omitted, or a method of emitting heat from the active layer.

The embodiment attempts to solve the heat dissipation problem by uniformly supplying current when implementing a light-emitting device which is thin and omits a growth substrate or a metal support.

A light emitting structure including a first conductivity type semiconductor layer, an active layer on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer on the active layer; A first electrode disposed on at least a part of a side surface of the first conductivity type semiconductor layer; And a second electrode disposed on the second conductivity type semiconductor layer and including a penetrating electrode passing through the light emitting structure and a branch electrode disposed on the second conductivity type semiconductor layer, The penetrating electrode provides a light emitting element exposed to a lower region of the light emitting structure.

The penetrating electrode may be disposed at a distance from the center of the surface of the second conductivity type semiconductor layer toward the first electrode.

 The penetrating electrode may have a diameter of 1.2 micrometers to 1.5 micrometers.

The branch electrode includes a first branched electrode in the first electrode direction and a second excitation electrode in the opposite direction to the first branched electrode, wherein the length of the first branched electrode is longer than the length of the second branched electrode , The width of the first branched electrode may be greater than the width of the second branched electrode.

The light emitting structure may include a first mesa region, the first conductive semiconductor layer may include a second mesa region, and the first electrode may be disposed on the first conductive semiconductor layer of the second mesa region.

The first electrode includes a first portion extending from a side surface of the first conductivity type semiconductor layer in the second mesa region and a second portion extending from the side surface of the first conductivity type semiconductor layer in the second mesa region, And a third portion disposed on an upper surface of the first conductive semiconductor layer of the second mesa region and connected to the second portion.

Another embodiment includes a circuit board; A plurality of light emitting elements according to any one of claims 1 to 9 arranged on the circuit board; A first electrode line electrically connected to the first electrodes in a lower region adjacent to the first conductive type semiconductor layer and a second electrode line electrically connected to the through electrodes in a lower portion of the light emitting elements, Array module.

In the light emitting device and the light emitting device array module according to the embodiments, the second electrode is disposed in the first mesa etching area as a penetrating electrode, so that the heat generated in the light emitting structure, particularly, the active layer can be emitted to the outside.

Although the current flow in the region adjacent to the second mesa etching region in the light emitting structure can be weakened, current can be uniformly supplied to the entire region of the light emitting structure through the adjustment of the position of the penetrating electrode and the adjustment of the length and thickness of the branch electrode .

In addition, both the first electrode line and the second electrode line may be provided below the light emitting device to emit light to the upper region of FIG.

1 is a sectional view of a first embodiment of a light emitting device,
FIG. 2A is a perspective view of FIG. 1,
2B and 2C are views illustrating a second electrode structure of the light emitting device,
3A to 3H are views showing a manufacturing process of a light emitting device,
4 is a diagram illustrating an embodiment of a smart device including a light emitting device array.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In the description of the embodiment according to the present invention, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

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 of each component does not entirely reflect the actual size.

1 is a sectional view of a first embodiment of a light emitting device.

The light emitting device 100 according to the embodiment includes the light emitting structure 120 including the first conductive semiconductor layer 122, the active layer 124, and the second conductive semiconductor layer 126, The first electrode 142 on the first conductivity type semiconductor layer 122, the second electrode 146 on the second conductivity type semiconductor layer 126, the first electrode 142 on the first conductivity type semiconductor layer 122, And an insulating layer (150).

The light emitting structure 120 has a first mesa region and a second mesa region. The first mesa region includes a first conductive semiconductor layer 122, an active layer 124, Type semiconductor layer 126 and the second mesa region may be disposed only on the first conductivity type semiconductor layer 122. [

3B, in the first etching process for exposing the upper surface of the first conductivity type semiconductor layer 122 to form the region where the first electrode 142 is to be disposed, A second etching process for re-etching the edge regions of the exposed first conductivity type semiconductor layer 122 as shown in FIG. 3C in order to increase the arrangement area of the first electrode 142 The second mesa region can be formed.

Although the side surfaces of the first mesa region and the second mesa region are shown as being vertically close to each other, they may be actually arranged at an angle.

The first conductive semiconductor layer 122 may be formed of a compound semiconductor such as a Group III-V or a Group II-VI, and may be doped with a first conductive dopant to form a first conductive semiconductor layer. The first conductivity type semiconductor layer 122 is made of a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0? X? 1, 0? _Y? 1, 0? _X + And may be formed of any one or more of AlGaN, GaN, InAlGaN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP, for example.

When the first conductive semiconductor layer 122 is an n-type semiconductor layer, the first conductive dopant may include n-type dopants such as Si, Ge, Sn, Se, and Te. The first conductive semiconductor layer 122 may be formed as a single layer or a multilayer, but is not limited thereto.

The first conductivity type semiconductor layer 122 forms a second mesa region on one side (right side in FIG. 1) around the first mesa region and a step on the right side of the second mesa region.

The active layer 124 is disposed on the top surface of the first conductive semiconductor layer 122 on the first mesa region and may have a single well structure, a multiple well structure, a single quantum well structure, a multi quantum well (MQW) , A quantum dot structure, or a quantum wire structure.

InGaN / InGaN, InGaN / InGaN, AlGaN / GaN, InAlGaN / GaN, GaAs (InGaAs), and AlGaN / AlGaN / InGaN / / AlGaAs, GaP (InGaP) / AlGaP, but is not limited thereto. The well layer may be formed of a material having an energy band gap smaller than the energy band gap of the barrier layer.

The second conductive semiconductor layer 126 may be formed of a semiconductor compound on the surface of the active layer 124. The second conductive semiconductor layer 126 may be formed of a compound semiconductor such as a Group III-V or a Group II-VI, and may be doped with a second conductive dopant. The second conductivity type semiconductor layer 126 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 + And may be formed of any one or more of AlGaN, GaN AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP.

When the second conductive semiconductor layer 126 is a p-type semiconductor layer, the second conductive dopant may be at least one selected from the group consisting of Mg, Zn, Ca, Sr, Ba and the like. The second conductive semiconductor layer 126 may be formed as a single layer or a multilayer, but the present invention is not limited thereto.

A light transmitting conductive layer 130 is formed on the second conductive semiconductor layer 126 by ITO or the like so that current spreading from the second electrode 146 to the second conductive semiconductor layer 126 is performed. ) Effect can be improved.

The first conductivity type semiconductor layer 122 is exposed by mesa etching from the light transmissive conductive layer 130 to the portions of the second conductivity type semiconductor layer 126, the active layer 124 and the first conductivity type semiconductor layer 122 An area where the first electrode 146 is to be formed can be secured.

The region of the second electrode 146 through which the penetrating electrode portion is to be formed through the second conductive type semiconductor layer 126, the active layer 124, and the first conductivity type semiconductor layer 122 from the light transmissive conductive layer 130 .

The first electrode 142 and the second electrode 146 may be disposed in contact with the first conductive semiconductor layer 122 and the second conductive semiconductor layer 126, respectively.

A first insulating layer 150 is formed on the exposed surface of the light emitting structure 120 and the first electrode 142 and on the exposed surface of the second electrode 146. The first insulating layer 150 is formed on one layer Or a plurality of layers. Since the second electrode 146 is not formed in the entire region of the light-transmitting conductive layer 130, a step structure may be formed at the edge of the first insulating layer 150 on the first mesa region as shown in FIG. have.

The first electrode 142 may include a first portion 142a, a second portion 142b, and a third portion 142c.

The first portion 142a extends from the side of the first conductive semiconductor layer 122 in the second mesa region and the second portion 142b extends from the side of the first conductive semiconductor layer 122 in the second mesa region. And the third portion 142c may be disposed in surface contact with the upper surface of the first conductive type semiconductor layer 122 in the second mesa region.

The upper surfaces of the first portion 142a, the second portion 142b and the third portion 142c are covered with the first insulating layer 150 so that the lower surface of the first portion 142a is exposed, Can be connected.

The second electrode 146 is formed on a part of the upper surface of the transmissive conductive layer 130 and the second conductivity type semiconductor layer 126 and the active layer 124 from the light transmissive conductive layer 130, May be disposed in a via hole formed through the layer (122).

The portion of the second electrode 146 that is disposed in the via hole may be referred to as a penetrating electrode, and the diameter t1 of the via hole may be 1.2 micrometers to 1.5 micrometers. When the diameter t1 of the via hole is smaller than 1.2 micrometer, the material of the second electrode 146 may not be sufficient to be injected considering the thickness of the second insulating layer 150a. If the diameter is larger than 1.5 micrometers, 124 may increase and the luminous efficiency may be lowered.

The second insulating layer 150a may be disposed inside the via hole to isolate the penetrating electrode from the active layer 124 and the first conductive type semiconductor layer 122. [ The second insulating layer 150a may include the same material as the first insulating layer 150 and the second insulating layer 150a may be formed in the region of the via hole formed in the second conductive semiconductor layer 126, The penetrating electrode may be in direct contact with the second conductive type semiconductor layer 126.

FIG. 2A is a perspective view of FIG. 1, and FIGS. 2B and 2C are views illustrating a second electrode structure of a light emitting device. Hereinafter, the second electrode structure of the light emitting device will be described in detail with reference to FIGS. 2A to 2C.

In FIG. 2A, 'A' represents the upper surface of the first mesa region, and the second electrode 146 and the insulating layer 150 are sequentially disposed on the light emitting structure. In the 'B' region, the insulating layer 150 is disposed on the light emitting structure on the side of the first mesa region, the 'C' region is disposed on the upper surface of the second mesa region, and the insulating layer 150 is disposed on the light emitting structure , And the 'D' region may be disposed on the light emitting structure on the side of the second mesa region.

The first electrode 142 may be disposed to extend laterally from the 'C' region, a portion of the 'D' region, and the 'D' region. The second electrode 146 is disposed in the 'A' region, and the penetrating electrode passes through the light emitting structure or the like.

The second electrode 146 and the penetrating electrode c are shown in FIG. 2B. The penetrating electrode may be disposed at the center of the second mesa region, but the first mesa region direction to the first electrode 142 direction As shown in Fig. When the amount of current injected into the active layer is uneven and especially the amount of current supplied to the right side of the second mesa region is small, the arrangement of the penetrating electrode (c) described above can uniformly supply current to the entire region of the active layer.

In FIG. 2C, a body electrode 146a, a first branched electrode 146b, and a second branched electrode 146c, which form a second electrode, are illustrated. A first branch electrode 146b is branched from the body electrode 146a toward the first electrode and a second branch electrode 146b is branched from the body electrode 146a toward the first electrode. And is branched from the body electrode 146b in the direction opposite to the first branched electrode.

In FIG. 2C, the length of the first branched electrode 146a is longer than the length of the second branched electrode 146b, and the current injection into the active layer from the first electrode direction to the second mesa direction can be increased. The increase of the current injection into the active layer adjacent to the first electrode direction to the second mesa region direction may be achieved by forming the first branched electrode 146a to have a thickness larger than the thickness of the second branched electrode 146b.

3A to 3H are views showing a manufacturing process of a light emitting device.

The light emitting structure 120 and the transparent conductive layer 130 are grown on the substrate 110 as shown in FIG.

The composition of the substrate 110, the light emitting structure 120, and the light transmitting conductive layer 130 is the same as described above.

The light emitting structure 120 including the first conductivity type semiconductor layer, the active layer, and the second conductivity type semiconductor layer may be formed by, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD) ), A plasma enhanced chemical vapor deposition (PECVD), a molecular beam epitaxy (MBE), a hydride vapor phase epitaxy (HVPE), or the like. , But is not limited thereto.

The transparent conductive layer 130 made of ITO can be grown to a thickness (t2, Fig. 3B) of 40 nanometers, for example. The thickness of the substrate 110 may be several times to several hundred times larger than that of the light emitting structure 120 and the light transmitting conductive layer 130. However, for simplicity of explanation, the thickness of the substrate 110 is small.

3B, a part of the light emitting structure 120 is firstly etched to expose a part of the upper surface of the first conductivity type semiconductor layer 122 in the first mesa region. At this time, the thickness t3 of the light emitting structure 120 to be firstly etched is about 1 micrometer, and the active layer 124 and the second conductivity type semiconductor layer 126 can be removed in a region except for the first mesa region have.

3C, the thickness t4 of the first conductive type semiconductor layer 122 to be etched at this time is the same as that of the first conductive type semiconductor layer 122 May be about 2 micrometers. In addition, the first conductivity type semiconductor layer 122 may be exposed on the upper surface of the second mesa region (second mesa).

A via hole is formed from the light transmissive conductive layer 130 to the bottom surface of the light emitting structure 120, as shown in FIG. 3D. At this time, the diameter of the via hole is as described in FIG. 1, and a part of the substrate 110 under the via hole can also be etched.

A second insulating layer 150a is formed on a part of the inner surface of the via hole and a second electrode 146 material is formed on a part of the upper surface of the transparent conductive layer 130 and on the inner surface of the via hole as shown in FIG. So that the second electrode 146 can be formed.

At this time, the second insulating layer 150a may be grown to cover at least the bottom surface of the via hole to the entire active layer (MQW).

The first electrode 142 may be formed on the light emitting structure 120 forming a step between a part of the upper surface of the light emitting structure 120 forming the second mesa region and the side surface and the second mesa region.

The first electrode 142 and the second electrode 146 may be formed of a metal having a predetermined thickness of, for example, 20 nm / 500 nm / 20 nm, such as Cr / Al / Ni / Nanometers / 500 nanometers in thickness, but not always limited thereto.

A first insulating layer 150 is formed on the surfaces of the first electrode 142 and the second electrode 146, the light-transmitting conductive layer 130 and the exposed light-emitting structure 120, By weight. The first insulating layer 150 may be formed with a stepped region s on the second mesa region since the first electrode 142 is disposed in only a portion of the upper surface of the light emitting structure 120 in the second mesa region have.

The substrate 110 and a part of the light emitting structure 120 are removed as shown in FIG. 3G. At this time, the removal of the substrate may be performed by a method of laser lift off (LLO), or by dry and wet etching.

When the excimer laser light having a certain wavelength in the direction of the substrate 110 is focused and irradiated by the laser lift-off method, heat energy is concentrated on the interface between the substrate 110 and the light emitting structure 120 The interface is separated into gallium and nitrogen molecules, and the substrate 110 is instantaneously separated from the portion where the laser beam passes.

3H, a part of the light emitting structure 120 may be removed by etching or the like, and may be removed until the lower surface of the first electrode 142 is exposed. For example, The light emitting structure 120, particularly the first conductivity type semiconductor layer, having a thickness t5 can be removed. At this time, part of the first insulating layer 150, the second insulating layer 150b, and the second electrode 146 may also be etched and removed.

Although not shown, a circuit board is disposed on the lower surface of each light emitting element, and the first electrode line and the second electrode line of the circuit board are connected to the first electrode 142 and the second electrode of the light emitting element, respectively, The module can be manufactured.

At this time, the first electrode line of the circuit board contacts the lower surface of the first portion 142a of the first electrode of Fig. 1, and the second electrode line may contact the lower surface of the penetrating electrode of the second electrode 146 . At this time, the penetrating electrode can emit heat from the inside of the light emitting structure toward the second electrode line.

In the light emitting device and the light emitting device array module described above, the second electrode is disposed in the first mesa etching region as a penetrating electrode, so that heat generated in the light emitting structure, particularly, the active layer can be emitted to the outside.

Although the current flow in the region adjacent to the second mesa etching region in the light emitting structure can be weakened, current can be uniformly supplied to the entire region of the light emitting structure through the adjustment of the position of the penetrating electrode and the adjustment of the length and thickness of the branch electrode .

In addition, both the first electrode line and the second electrode line may be provided below the light emitting device to emit light to the upper region of FIG.

The light emitting element array module can form pixels in various display devices as described above, and can also be used as a light source of a lighting device. In particular, when the FPCB is used as a circuit board, it can be used as a light source of a wearable device such as a smart watch by implementing a light emitting device array capable of bending due to the flexibility of the FPCB.

5 is a view showing an embodiment of a smart watch including the light emitting element array module described above.

The smart watch 300 may perform a pairing with an external digital device and the external digital device may be a digital device capable of establishing a communication connection with the smart watch 300. For example, 410, an IPTV (Internet Protocol Television) 420, and the like.

The light emitting device array 310 described above can be used as a light source of the smart watch 300 and the wear of the wrist due to the flexibility of the FPCB can be realized due to the small size of the light emitting device.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood 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
120: light emitting structure 130: transparent conductive layer
142: first electrodes 142a to 142c: first to third portions
146: second electrode 146a: body electrode
146b, 146c: first and second branched electrodes 150: first insulating layer
150a: second insulating layer

Claims (10)

A light emitting structure including a first conductivity type semiconductor layer, an active layer on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer on the active layer;
A first electrode disposed on at least a part of a side surface of the first conductive semiconductor layer; And
And a second electrode disposed on the second conductivity type semiconductor layer and including a penetrating electrode disposed in a via hole passing through the light emitting structure and a branch electrode disposed on the second conductivity type semiconductor layer,
Wherein the first electrode and the penetrating electrode are exposed in a lower region of the light emitting structure. The method according to claim 1,
Wherein the penetrating electrode is disposed apart from the center of the surface of the second conductivity type semiconductor layer in the direction of the first electrode. The method according to claim 1,
Wherein the via hole has a diameter of 1.2 micrometers to 1.5 micrometers. The method according to claim 1,
Wherein the branch electrode includes a first branched electrode in the first electrode direction and a second excitation electrode in the opposite direction to the first branched electrode,
Wherein a length of the first branched electrode is longer than a length of the second branched electrode. 5. The method of claim 4,
Wherein the branch electrode includes a first branched electrode in the first electrode direction and a second excitation electrode in the opposite direction to the first branched electrode,
Wherein a width of the first branched electrode is larger than a width of the second branched electrode. The method according to claim 1,
The light emitting structure may include a first mesa region, the first conductive semiconductor layer may include a second mesa region, and the first electrode may be disposed on the first conductive semiconductor layer of the second mesa region, . The method according to claim 6,
Wherein the first electrode includes a first portion extending from a side surface of the first conductivity type semiconductor layer of the second mesa region. 8. The method of claim 7,
Wherein the first electrode further comprises a second portion in surface contact with a side surface of the first conductive type semiconductor layer of the second mesa region and connected to the first portion. 9. The method of claim 8,
Wherein the second electrode further comprises a third portion disposed on an upper surface of the first conductive semiconductor layer of the second mesa region and connected to the second portion. A circuit board;
A plurality of light emitting elements according to any one of claims 1 to 9 arranged on the circuit board;
A first electrode line electrically connected to the first electrodes in a lower region adjacent to the first conductive type semiconductor layer;
And a second electrode line electrically connected to the penetrating electrodes at a lower portion of the light emitting elements.

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