KR102328472B1 - Ohmic contacts and light emitting diode comprising the same - Google Patents

Abstract

An embodiment includes a first layer disposed on a nitride-based semiconductor layer and made of Al; _{Disclosed is an ohmic bonding comprising a second layer including at least one M x} Al _y alloy formed by reacting with Al of the first layer, and a third layer disposed on the second layer and made of Au as a material.

Description

Ohmic junction and light emitting device including the same

The present invention relates to an ohmic junction and a light emitting device including the same.

A light emitting diode (LED) is one of the light emitting devices that emit light when a current is applied. The light emitting device can emit high-efficiency light, and thus has an excellent energy-saving effect.

Recently, the luminance problem of the light emitting device has been greatly improved, and it is applied to various devices such as a backlight unit of a liquid crystal display device, an electric sign board, a display device, and a home appliance.

In particular, nitride-based semiconductor light emitting devices have excellent electron affinity, electron mobility, electron saturation rate, and field breakdown voltage characteristics to realize high efficiency and high output, and do not contain harmful substances such as arsenic (As) and mercury (Hg). Therefore, it is attracting a lot of attention as an environmentally friendly device.

In the nitride-based semiconductor light emitting device, the junction between the semiconductor and the metal is difficult to form a surface level of the nitride semiconductor, so the difference in the work function between the semiconductor and the metal becomes a junction barrier. The ohmic junction is formed on the nitride semiconductor layer to minimize the influence of the junction barrier between the nitride semiconductor and the metal on the light emitting device. Ohmic bonding uses an electrode structure containing Al, and Al diffuses to other layers during the heat treatment process to form a compound, which combines with Au to compound Au ₄ Al, Au ₈ Al ₃ , Au ₂ Al, AuAl ₂ to form The compound formed by diffusion of Al has a high electrical resistance and roughens the surface, thereby deteriorating the electrical properties of the light emitting device.

To prevent this, a metal layer that prevents the diffusion of the Al layer is used, but there is a problem in that it cannot perform the function of preventing the diffusion of Al during a high temperature heat treatment process.

In particular, in the case of an ultraviolet light emitting device, an ohmic junction is formed on an AlGaN layer having a high Al ratio through high temperature heat treatment.

An embodiment provides an ohmic junction having improved surface properties and electrical properties, and a light emitting device including the same.

In addition, there is provided an ohmic junction in which electrical properties are not deteriorated even with high-temperature heat treatment, and a light emitting device including the same.

An ohmic junction according to an embodiment of the present invention includes: a first layer disposed on a nitride-based semiconductor layer and made of Al; A second layer including at least one M _x Al _y (M is a metal) alloy formed by reacting with Al of the first layer, and a third layer disposed on the second layer and made of Au can be

M may have a higher melting point than the melting point of Al.

The M may react with the Al at a heat treatment temperature of 700 degrees or more to form the second layer.

M may be any one metal selected from Cu, Pd, and Ag.

The M _x Al _y may be Cu _x Al _y (1≤x≤9, 1≤y≤4).

In the Cu _x Al _y alloy, y may have a value greater than or equal to x.

The Cu _x Al _y may have an electrical resistance of 20Ω or less.

The second layer may include at least one alloy selected from _{CuAl, CuAl 2} , Cu ₄ Al ₃ , Cu ₃ Al ₂ and Cu ₉ Al _{4 .}

The electrical conductivity of the M _x Al _y alloy may be greater than that of the Al-Au alloy.

It may be configured to further include a protective layer disposed on the second layer to prevent oxidation of the second layer.

The protective layer may be made of at least one metal or alloy selected from Cr, Ni, Ti, and Au.

The nitride-based semiconductor may be an AlGaN-based nitride-based semiconductor.

A light emitting device according to another embodiment of the present invention includes a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer; a first electrode disposed on one side of the light emitting structure and electrically connected to the first semiconductor layer; a second electrode disposed on one side of the light emitting structure and electrically connected to the second semiconductor layer; A first layer disposed between the second electrode and the second semiconductor layer and made of Al, _{a second layer including at least one M x} Al _y alloy formed by reacting with Al of the first layer, and the It is disposed on the second layer and may be configured to include an ohmic junction including a third layer made of Au.

M may have a higher melting point than the melting point of Al.

The M may react with the Al at a heat treatment temperature of 700 degrees or more to form the second layer.

M may be any one metal selected from Cu, Pd, and Ag.

The electrical conductivity of the M _x Al _y alloy may be greater than that of the Al-Au alloy.

It may be configured to further include a protective layer disposed on the second layer to prevent oxidation of the second layer.

The protective layer may be made of at least one metal or alloy selected from Cr, Ni, Ti, and Au.

The second semiconductor layer may be an AlGaN-based nitride-based semiconductor.

According to the embodiment, the surface characteristics and electrical characteristics of the light emitting device are improved.

In addition, electrical properties are not deteriorated even by high-temperature heat treatment.

1 is a conceptual diagram of a light emitting device according to an embodiment of the present invention;
2 is a cross-sectional view of an ohmic junction according to an embodiment of the present invention;
3 is a cross-sectional view of an ohmic junction according to another embodiment of the present invention;
4 is a cross-sectional view of an ohmic junction according to another embodiment of the present invention;
5 is a cross-sectional view of an ohmic junction according to another embodiment of the present invention;
6 is a cross-sectional view of an ohmic junction according to another embodiment of the present invention;
7 is a process diagram of ohmic bonding according to an embodiment of the present invention;
8 is a process diagram of ohmic bonding according to another embodiment of the present invention;
9 is a graph for comparing the electrical conductivity of a second layer formed according to the prior art and an embodiment of the present invention;
10 and 11 are views showing the surface of the ohmic junction formed according to the prior art and an embodiment of the present invention,
12 is an enlarged view of the surface of the ohmic junction formed according to the prior art and an embodiment of the present invention;
13 is a view for explaining the function of the protective layer of the ohmic junction according to an embodiment of the present invention;
14 is a flowchart of a method of manufacturing a light emitting device according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms including an ordinal number such as second, first, etc. may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as the first component, and similarly, the first component may also be referred to as the second component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is mentioned that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings, but the same or corresponding components are given the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted.

1 is a conceptual diagram of a light emitting device according to an embodiment of the present invention.

Referring to FIG. 1 , a light emitting device 100A according to an embodiment of the present invention includes a light emitting structure 110 including a plurality of semiconductor layers, a first electrode 140 electrically connected to the light emitting structure 110 and The second electrode 130 may be included.

The light emitting structure may include a first semiconductor layer, an active layer, and a second semiconductor layer.

The first semiconductor layer 113 may be a compound semiconductor of group III-V or group II-VI, and may be doped with a first dopant. The first semiconductor layer 113 may _{satisfy the compositional formula of Al x} In _y Ga(1-xy)N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, the first semiconductor layer 113 may include at least one of AlGaN, InAlGaN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP.

When the first semiconductor layer 113 is a p-type semiconductor layer, the first conductivity-type dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, Ba, or the like. The first semiconductor layer 113 may be formed as a single layer or a multilayer, but is not limited thereto.

In the case of an ultraviolet (UV), deep UV, or non-polarized light emitting device, the first semiconductor layer 113 may include at least one of InAlGaN and AlGaN. If the first semiconductor layer 113 is a p-type semiconductor layer, the first semiconductor layer 113 may include graded AlGaN having an aluminum concentration gradient in order to reduce a lattice difference, and may include 10 nm to 100 nm. may have a thickness of

The active layer 112 disposed between the first semiconductor layer 113 and the second semiconductor layer 111 may include a single well structure, a multi-well structure, a single quantum well structure, a multi-quantum well (MQW) structure, and a quantum dot structure. It may include any one of a structure or a quantum wire structure.

The active layer 112 is formed of a well layer and a barrier layer, for example, InGaN/GaN, InGaN/InGaN, GaN/AlGaN, InAlGaN/GaN, GaAs (InGaAs)/AlGaAs, GaP using a III-V group element compound semiconductor material. (InGaP)/AlGaP may be formed in any one or more pair (pair) structure, but is not limited thereto. The well layer may be formed of a material having an energy band gap smaller than that of the barrier layer.

The second semiconductor layer 111 may be implemented as a compound semiconductor of group III-V or group II-VI, and may be doped with a second dopant. The second semiconductor layer 111 may _{satisfy the compositional formula of Al x} In _y Ga(1-xy)N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, the second semiconductor layer 111 may include any one or more of AlGaN, InAlGaN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP.

When the second semiconductor layer 111 is an n-type semiconductor layer, the second conductivity-type dopant may include an n-type dopant such as Si, Ge, Sn, Se, Te, or the like. The second semiconductor layer 111 may be formed as a single layer or a multilayer, but is not limited thereto.

In the case of an ultraviolet (UV), deep UV, or non-polarized light emitting device, the second semiconductor layer 111 may include at least one of InAlGaN and AlGaN. When the second semiconductor layer 111 is made of AlGaN, the Al content may be 50%. In the case of the second semiconductor layer 111, the n-type semiconductor layer, the second semiconductor layer 111 may be formed of Al _{0 .5} GaN, for example 0.6 to 2.6 ㎛ ㎛, may have a thickness of 1.6 ㎛ .

According to the embodiment, the upper surface of the light emitting structure 110 may have an uneven portion 111a. However, the present invention is not necessarily limited thereto. For example, the upper surface of the second semiconductor layer 111a may be a flat surface.

The first electrode 140 and the second electrode 130 are disposed on one side of the light emitting structure 110 . Here, one side may be opposite to the main light emitting surface of the light emitting structure 110 . The light emitting device 100A according to an embodiment of the present invention may be a flip chip or a thin film flip chip (TFFC) in which the first electrode 140 and the second electrode 130 are disposed on the same plane. .

The light emitting device according to the present invention is not limited to a flip chip type, and may be applied to a horizontal chip (Lateral Chip) and a vertical chip (Vertical Chip) type. In the horizontal chip and the vertical tip structure, the arrangement relationship of the light emitting structure, the first electrode, and the second electrode is different, and the ohmic junction is disposed between the second semiconductor layer and the second electrode of the light emitting structure.

The first electrode 140 may be electrically connected to the first semiconductor layer 113 of the light emitting structure 110 , and the second electrode 130 may be electrically connected to the second semiconductor layer 111 .

The first electrode 140 may be electrically connected to the first semiconductor layer 113 through the reflective layer 114 , and the second electrode 130 may be electrically connected to the second semiconductor layer 111 through a contact hole. have. The extension 131 of the second electrode 130 filled in the contact hole is electrically insulated from the active layer 112 and the first semiconductor layer 113 by the protective layer 120 .

The first electrode 140 and the second electrode 130 are disposed adjacent to each other at one side of the light emitting structure 110 . In this case, the first electrode 140 and the second electrode 130 may be spaced apart from each other by a predetermined interval for electrical insulation. The thickness of the first electrode 140 and the second electrode 130 may be the same, but is not limited thereto.

The support layer 170 is formed to surround at least one side of the light emitting structure 110 , the first electrode 140 , and the second electrode 130 . The support layer 170 may include an insulating part 171 disposed between the first electrode 140 and the second electrode 130 . The support layer 170 may be a cured polymer resin. There is no limitation on the type of polymer resin.

The ohmic junction 150 is disposed between the second electrode 130 and the second semiconductor layer 113 . One surface of the ohmic junction 150 is electrically connected to the second electrode 130 and electrically connected to the second semiconductor layer 113 through the other surface. The side surface of the ohmic junction 150 may be covered by the protective layer 120 , but is not limited thereto.

2 is a cross-sectional view of an ohmic junction according to an embodiment of the present invention.

Referring to FIG. 2 , the ohmic junction according to an embodiment of the present invention is configured by sequentially stacking a first layer 151 , a second layer 152 , and a third layer 153 from the second semiconductor layer 113 . can be

The first layer 151 may be formed of Al and an alloy containing Al. The thickness of the first layer 151 may be, for example, 50 to 500 nm, but is not limited thereto, and may have various thicknesses depending on the thickness of the metal M forming the second layer 152 .

The second layer 152 may include at least one M _x Al _y alloy formed by reacting with Al of the first layer 151 . The thickness of the second layer 152 may be, for example, 5 to 500 nm, but is not limited thereto, and may have various thicknesses according to the thickness of the first layer 151 .

M of the second layer 152 may be a metal having a melting point higher than that of Al. M reacts with Al at a heat treatment temperature of 700 degrees or more to form the second layer 152 . During the heat treatment process at a temperature higher than the melting point, Al in the first layer 151 diffuses to form a compound with M to form the second layer 152 .

M may be any one metal selected from Cu, Pd, and Ag. However, the present invention is not necessarily limited thereto. As a metal having a melting point higher than that of Al, an alloy formed by a compound reaction with Al may be a metal having greater electrical conductivity than that of an Al-Au alloy.

In addition, M may be a metal in which the electrical conductivity of the alloy formed by the chemical reaction with Al is greater than the electrical conductivity of the Al-Au alloy, and the electrical resistance deviation is 5 Ω or less.

The third layer 153 is disposed on the second layer 152 and may be made of Au and an alloy containing Au. The thickness of the third layer 153 may be, for example, 20 to 500 nm, but is not necessarily limited thereto.

3 is a cross-sectional view of an ohmic junction according to another embodiment of the present invention.

Referring to FIG. 3 , an ohmic junction according to another embodiment of the present invention is performed from the second semiconductor layer 113 to the first layer 151 , the second layer 152 , the protective layer 154 , and the third layer 153 . These may be sequentially stacked.

The ohmic bonding according to the embodiment of FIG. 3 is a configuration in which a protective layer is added to the embodiment of FIG. 2, and a description overlapping with that of FIG. 2 will be omitted.

The protective layer 154 may be disposed on the second layer 152 to prevent oxidation of the second layer 152 . The protective layer 154 may be made of, for example, at least one metal or alloy selected from Cr, Ni, Ti, and Au. In the protective layer 154 , a metal or a metal alloy having low reactivity with oxygen is disposed on the second layer 152 to prevent the second layer 152 from combining with oxygen.

4 is a cross-sectional view of an ohmic junction according to another embodiment of the present invention.

Referring to FIG. 4 , in the ohmic junction according to another embodiment of the present invention, the first layer 1510 , the second layer 1520 , and the third layer 1530 are sequentially stacked from the second semiconductor layer 1130 . can be

The first layer 1510 may be formed of Al and an alloy containing Al. The thickness of the first layer 1510 may be, for example, 50 to 500 nm, but is not necessarily limited thereto, and may have various thicknesses depending on the thickness of the metal Cu forming the second layer 1520 .

The second layer 1520 may include at least one Cu _x Al _y alloy (1≤x≤9, 1≤y≤4) formed by reacting with Al of the first layer 1510 . The thickness of the second layer 1520 may be, for example, 5 to 500 nm, but is not limited thereto, and may have various thicknesses according to the thickness of the first layer 1510 .

Cu reacts with Al at a heat treatment temperature of 700 degrees or more to form the second layer 1520 . During the heat treatment process at a temperature higher than the melting point, Al in the first layer 1510 diffuses to form a compound with Cu, thereby forming the second layer 1520 .

_{In the Cu x} Al _y alloy forming the second layer 1520 , y may have a value greater than or equal to x. The second layer 1520 may include, for example, at least one alloy selected from _{CuAl, CuAl 2} , Cu ₄ Al ₃ , Cu ₃ Al _{2 ,} and Cu ₉ Al _{4 .}

However, the present invention is not necessarily limited thereto, and the second layer 1520 may include all Cu _x Al _y alloys having an electrical resistance of 20 Ω or less and an electrical resistance deviation of 5 Ω or less and other impurities.

The third layer 1530 is disposed on the second layer 1520 and may be made of Au and an alloy containing Au. The thickness of the third layer 1530 may be, for example, 20 to 500 nm, but is not limited thereto.

5 is a cross-sectional view of an ohmic junction according to another embodiment of the present invention.

Referring to FIG. 5 , an ohmic junction according to another embodiment of the present invention is performed from the second semiconductor layer 1130 to the first layer 1510 , the second layer 1520 , the protective layer 1540 , and the third layer 1530 . ) may be sequentially stacked.

The ohmic bonding according to the embodiment of FIG. 5 is a configuration in which a protective layer is added to the embodiment of FIG. 4, and a description overlapping with that of FIG. 4 will be omitted.

The protective layer 1540 may be disposed on the second layer 1520 to prevent oxidation of the second layer 1520 . The protective layer 1540 may be made of, for example, at least one metal or alloy selected from Cr, Ni, Ti, and Au. In the protective layer 1540 , a metal or a metal alloy having low reactivity with oxygen is disposed on the second layer 1520 to prevent bonding between the second layer 1520 and oxygen.

6 is a cross-sectional view of an ohmic junction according to another embodiment of the present invention.

Referring to FIG. 6 , an ohmic junction according to another embodiment of the present invention is performed from the second semiconductor layer 1130 to the bottom layer 1550 , the first layer 1510 , the second layer 1520 , and the protective layer 1540 . , the third layer 1530 may be sequentially stacked.

The ohmic bonding according to the embodiment of FIG. 6 is a configuration in which a bottom layer is added to the embodiment of FIG. 5, and a description overlapping with that of FIG. 5 will be omitted.

The bottom layer 1550 is disposed between the first layer 1520 and the second semiconductor layer 1130 to prevent diffusion of Al in the first layer into the semiconductor layer during high-temperature heat treatment. The bottom layer 1550 may include, for example, at least one of Cr, Ti, Nb, V, W, Ta, Re, Mo, Mn, Pt, Pd, Rh, Y and Zr having a melting point higher than that of Al. may be included, and a plurality of layers instead of a single layer may be disposed between the first layer 1520 and the second semiconductor layer 1130 .

7 is a process diagram of ohmic bonding according to an embodiment of the present invention.

Referring to FIG. 7 , in the ohmic bonding according to an embodiment of the present invention, heat treatment is performed after laminating a first layer 151 , an M metal layer M, and a third layer 153 on the second semiconductor layer 113 . is formed by In this case, the first layer 151 , the M metal layer M, and the third layer 153 may be deposited by a sputtering method, a vacuum deposition method, plating, a film forming method, or the like, but is not limited thereto.

The heat treatment process is carried out at a high temperature higher than the Al melting point, for example, may be carried out at a temperature of 700 degrees or higher, but is not limited thereto, and may be determined in consideration of the relationship between temperature and contact resistance.

Al of the first layer 151 is diffused into the M layer (M) by the heat treatment process to form the second layer 152 including _{at least one M x} Al _{y alloy.}

8 is a flowchart of ohmic bonding according to another embodiment of the present invention.

Referring to FIG. 8 , the heat treatment process is performed in a state in which the protective layer 1540 is additionally stacked on the M layer (M). The protective layer 1540 prevents the blackening (fog) phenomenon of the second layer 1520 by blocking the _{M x} Al _y alloy from combining with oxygen during the heat treatment process.

9 is a graph for comparing the electrical conductivity of a second layer formed according to an embodiment of the present invention and the prior art.

Referring to FIG. 9( a ), in the ohmic bonding according to the prior art, an Al-Au alloy is generated during heat treatment. In the case of an Al-Au alloy, the maximum electrical resistance is 50Ω and the electrical resistance deviation between the alloys is 40Ω, so the electrical conductivity of the ohmic bonding reduces the

Referring to FIG. 9(b), in the case of ohmic bonding according to an embodiment of the present invention, a Cu layer is laminated on the first layer and heat treatment is performed to form a second layer including _{Cu x} Al _{y alloy.} The second layer is CuAl, CuAl ₂ , Cu ₄ Al ₃ , Cu ₃ Al ₂ and Cu ₉ Al ₄ It contains at least one alloy among the alloys, and the electrical resistance of each alloy is 20 Ω or less, and the electrical resistance deviation between alloys is 5 Ω or less. _{In the case of the Cu x} Al _y alloy according to an embodiment of the present invention, since there is no significant difference from the electrical resistance of Al or Au, the reduction in electrical conductivity of the ohmic junction can be prevented.

10 and 11 are views showing a surface of an ohmic junction formed according to the prior art and an embodiment of the present invention.

Referring to FIG. 10( a ), it can be seen that the surface of the ohmic junction according to the prior art has different colors due to the unbalanced distribution of the Al-Au alloy. This phenomenon is due to the influence of _{AuAl 2} alloy having an electrical resistance that is about 30 times higher than that of Au or Al.

Referring to FIG. 10( b ), it can be confirmed that the color change of the surface portion does not occur in the ohmic bonding according to an embodiment of the present invention by forming an alloy having a small electrical resistance variation during high-temperature heat treatment.

Referring to FIG. 11( a ), the surface of the ohmic junction according to the prior art has an uneven surface state due to Al diffusion during high-temperature heat treatment. It can be seen that the surface of the junction is formed flat by accommodating the diffusion of Al during high-temperature heat treatment to form the second layer.

12 is an enlarged view of the surface of the ohmic junction formed according to the prior art and an embodiment of the present invention.

Referring to FIG. 12 ( a ), it can be seen that the surface of the ohmic junction according to the prior art is unevenly formed by Al diffused to the surface during high-temperature heat treatment. Referring to FIG. 12(b), it can be seen that the surface of the ohmic junction according to an embodiment of the present invention is formed to be flat by accommodating the diffusion of Al during high-temperature heat treatment to form a second layer.

13 is a view for explaining the function of a protective layer of an ohmic junction according to an embodiment of the present invention.

Referring to FIG. 13( a ), it can be seen that blackening occurs due to the combination of the second layer with oxygen when heat treatment is performed without a protective layer. 13(b) shows the surface of the ohmic junction subjected to high-temperature heat treatment in an environment in which 5% oxygen is injected, and FIG. represents the surface. 13(b) and 13(c), the protective layer blocks the bond between the second layer and oxygen to prevent the blackening phenomenon.

14 is a flowchart of a method of manufacturing a light emitting device according to an embodiment of the present invention.

First, referring to FIG. 14A , a light emitting structure 110 is formed on a substrate S. The light emitting structure 110 sequentially forms a second semiconductor layer 111 , an active layer 112 , and a first semiconductor layer 113 .

Here, the substrate S _{may be formed of at least one of sapphire (Al 2} O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not necessarily limited thereto. The substrate S may have sufficient mechanical strength to be well separated into separate chips through a scribing process and a breaking process without causing warpage to the nitride semiconductor.

Thereafter, as shown in FIG. 14B , the reflective layer 114 and the contact hole H are formed in the light emitting structure 110 , and the protective layer 120 is formed on the outer surface of the light emitting structure 120 . The inside of the contact hole H is insulated from the first semiconductor layer 113 and the active layer 112 by the protective layer 120 .

Thereafter, as shown in FIG. 14C , the first electrode 140 connected to the first semiconductor layer 113 and the second electrode 130 contacting the first semiconductor layer 113 are formed. The electrode may be patterned after the electrode material layer is formed by plating. The electrode material may include Cu, Ag, etc. having excellent conductivity.

Thereafter, as shown in FIG. 14D , the first pad 150 formed on the first electrode 140 and the second pad 160 formed on the second electrode 130 are formed. The first pad 150 and the second pad 160 may be made of the same material as the first electrode 140 .

Thereafter, the support layer 170 is filled on one surface of the light emitting device on which the first pad 150 and the second pad 160 are formed, and then cured. At least a portion of the support layer 170 may be formed between the first pad 150 and the second pad 160 , the side surfaces of the first electrode 140 and the second electrode 130 , and the side surface of the light emitting structure. .

Then, as shown in FIG. 14E, the substrate is removed. The substrate may be separated by irradiating a laser having a predetermined wavelength. The substrate may be removed by a laser lift-off method (LLO), but is not limited thereto. When the substrate is removed, an uneven portion 111a may be formed on the second semiconductor layer 111 .

Although only one light emitting device is illustrated in this drawing, a plurality of light emitting devices may be continuously formed on one substrate and then manufactured as a wafer level package in which a plurality of light emitting devices are separated.

Thereafter, as shown in FIG. 14F , an optical layer 190 is formed on at least a portion of the light emitting structure 110 , the first electrode 140 , the second electrode 130 , the first pad 150 , and the second pad 160 . Thus, a light emitting device package can be manufactured. The optical layer 190 may include a wavelength converter. The wavelength converter may be a YAG, silicate-based, or nitride-based phosphor, but is not necessarily limited thereto. For example, the wavelength converter may include quantum dots (QDs) or dyes.

A plurality of light emitting devices according to the present invention may be arranged on a substrate, and optical members such as a light guide plate, a prism sheet, and a diffusion sheet may be disposed on a light path of the light emitting device package. Such a light emitting device package, a substrate, and an optical member may function as a backlight unit.

In addition, it may be implemented as a display device, an indicator device, and a lighting device including a light emitting device package.

Here, the display device includes a bottom cover, a reflecting plate disposed on the bottom cover, a light emitting module emitting light, a light guide plate disposed in front of the reflecting plate and guiding light emitted from the light emitting module in front of the light guide plate An optical sheet comprising prism sheets disposed thereon, a display panel disposed in front of the optical sheet, an image signal output circuit connected to the display panel and supplying an image signal to the display panel, and a color filter disposed in front of the display panel. may include Here, the bottom cover, the reflector, the light emitting module, the light guide plate, and the optical sheet may form a backlight unit.

In addition, the lighting device includes a light source module including a substrate and a light emitting device package according to an embodiment, a heat sink for dissipating heat of the light source module, and a power supply unit that processes or converts an electrical signal received from the outside and provides it to the light source module may include For example, the lighting device may include a lamp, a head lamp, or a street lamp.

The head lamp includes a light emitting module including light emitting device packages disposed on a substrate, a reflector that reflects light emitted from the light emitting module in a predetermined direction, for example, forward, and a lens that refracts light reflected by the reflector forward. , and a shade that blocks or reflects a portion of light reflected by the reflector and directed to the lens to form a light distribution pattern desired by the designer.

In the above, the embodiment has been mainly described, but this is only an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are not exemplified above in the range that does not depart from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

110: light emitting structure
111: second semiconductor layer
112: active layer
113: first semiconductor layer
120: protective layer
130: second electrode
140: first electrode
150: ohmic junction
151, 1510: 1st floor
152, 1520: 2nd floor
153, 1530: 3rd floor
154, 1540: protective layer

Claims (20)

a first layer disposed on the nitride-based semiconductor layer and including Al;
a second layer comprising at least one Cu _x Al _y alloy formed by reacting with Al of the first layer; and
It is disposed on the second layer and includes a third layer containing Au,
The electrical conductivity of the CuxAly alloy is greater than that of the Al-Au alloy, and an ohmic junction having an electrical resistance of 20 Ω or less and an electrical resistance deviation of 5 Ω or less. delete According to claim 1,
The Cu reacts with the Al at a heat treatment temperature of 700 degrees or more to form the second layer. delete According to claim 1,
The Cu _x Al _y is Cu _x Al _y (1≤x≤9, 1≤y≤4) ohmic bonding. 6. The method of claim 5,
In the Cu _x Al _y alloy, y is an ohmic junction having a value greater than or equal to x. delete 6. The method of claim 5,
The second layer is an ohmic bonding comprising at least one alloy selected from _{CuAl, CuAl 2} , Cu ₄ Al ₃ , Cu ₃ Al ₂ and Cu ₉ Al _{4 .} delete According to claim 1,
Ohmic bonding further comprising a protective layer disposed on the second layer to prevent oxidation of the second layer. 11. The method of claim 10,
The protective layer is an ohmic bonding comprising at least one metal or alloy selected from Cr, Ni, Ti and Au. According to claim 1,
The nitride-based semiconductor is an AlGaN-based nitride-based semiconductor ohmic junction. a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer;
a first electrode disposed on one side of the light emitting structure and electrically connected to the first semiconductor layer;
a second electrode disposed on one side of the light emitting structure and electrically connected to the second semiconductor layer; and
A first layer disposed between the second electrode and the second semiconductor layer and comprising Al, a second layer comprising at least one Cu _x Al _y alloy formed by reacting with Al of the first layer, and the second layer It is disposed on the layer and comprises a third layer comprising Au,
The CuxAly alloy has electrical conductivity greater than that of the Al-Au alloy, and includes an ohmic junction having an electrical resistance of 20Ω or less and an electrical resistance deviation of 5Ω or less. delete 14. The method of claim 13,
The Cu reacts with the Al at a heat treatment temperature of 700 degrees or more to form the second layer. delete delete 14. The method of claim 13,
The light emitting device further comprising a protective layer disposed on the second layer to prevent oxidation of the second layer. 19. The method of claim 18,
The protective layer is a light emitting device comprising at least one metal or alloy selected from Cr, Ni, Ti and Au. 14. The method of claim 13,
The second semiconductor layer is an AlGaN-based nitride-based semiconductor light emitting device.

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