KR102158576B1 - Ultraviolet light emitting device and light emitting device package having the same - Google Patents

Abstract

The ultraviolet light emitting device according to the embodiment includes a substrate, a first conductivity type semiconductor layer disposed on the substrate, an active layer disposed on the first conductivity type semiconductor layer, and a second conductivity type semiconductor disposed on the active layer. A layer, a second electrode disposed on the second conductive type semiconductor layer, a first electrode disposed on a first conductive type semiconductor layer to be disposed outside the second electrode, and the second conductive type semiconductor layer And an insulating layer disposed in an edge region between the and the second electrode.
In the embodiment, by disposing an insulating layer under the second electrode adjacent to the first electrode, there is an effect of preventing the current from being concentrated to the edge and light emission from being concentrated at the edge.

Description

Ultraviolet light emitting device and light emitting device package including the same {ULTRAVIOLET LIGHT EMITTING DEVICE AND LIGHT EMITTING DEVICE PACKAGE HAVING THE SAME}

The embodiment relates to an ultraviolet light emitting device.

In general, a light emitting device is a compound semiconductor that converts electrical energy into light energy, and can be produced as a compound semiconductor such as Group III and Group V on the periodic table, and various colors by adjusting the composition ratio of the compound semiconductor Implementation is possible.

When a forward voltage is applied, the electrons in the n-layer and the holes in the p-layer are combined to emit energy equivalent to the band gap energy of the conduction band and the balance band. Is mainly emitted in the form of heat or light, and becomes a light emitting device when radiated in the form of light.

Recently, ultraviolet light emitting devices using ultraviolet rays have been developed, and such ultraviolet light emitting devices are used in various fields for purposes such as treatment and sterilization.

Conventional ultraviolet light emitting devices are composed of a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer. The luminous efficiency, such as a decrease in external quantum efficiency, decreases, resulting in a problem of lowering the sterilizing power.

In order to solve the above problems, the embodiment aims to provide an ultraviolet light emitting device for improving luminous efficiency and a flip chip light emitting device package including the same.

In order to achieve the above object, the ultraviolet light emitting device according to the embodiment includes a substrate, a first conductivity type semiconductor layer disposed on the substrate, an active layer disposed on the first conductivity type semiconductor layer, and the active layer. A second conductivity-type semiconductor layer disposed on, a second electrode disposed on the second conductivity-type semiconductor layer, a first electrode disposed on the first conductivity-type semiconductor layer to be disposed outside the second electrode, And an insulating layer disposed in an edge region between the second conductivity type semiconductor layer and the second electrode.

In the embodiment, by disposing an insulating layer under the second electrode adjacent to the first electrode, there is an effect of preventing the current from being concentrated to the edge and light emission from being concentrated at the edge.

In addition, the embodiment has an effect of improving luminous efficiency, such as lifetime and external quantum efficiency, by preventing light emission from being concentrated at the edge.

1 is a cross-sectional view showing an ultraviolet light emitting device according to a first embodiment.
2 is a cross-sectional view showing the movement of current in the ultraviolet light emitting device according to the first embodiment.
3 is a cross-sectional view showing an ultraviolet light emitting device according to a second embodiment.
4 is a cross-sectional view showing the movement of current in the ultraviolet light emitting device according to the second embodiment.
5 is a cross-sectional view illustrating a package of a flip chip light emitting device including an ultraviolet light emitting device according to embodiments.

Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

1 is a cross-sectional view showing an ultraviolet light-emitting device according to a first embodiment, and FIG. 2 is a cross-sectional view showing a current movement of an ultraviolet light-emitting device according to the first embodiment.

Referring to FIG. 1, the ultraviolet light emitting device according to the first embodiment includes a substrate 110, a buffer layer 181 disposed on the substrate 110, and a first conductivity type disposed on the buffer layer 181. A semiconductor layer 120, a current diffusion layer 182 disposed on the first conductivity type semiconductor layer 120, a strain control layer 183 disposed on the current diffusion layer 182, and the strain control layer The active layer 130 disposed on the 183, the electron blocking layer 184 disposed on the active layer 130, and the second conductivity type semiconductor layer 140 disposed on the electron blocking layer 184 And, a light-transmitting electrode layer 185 disposed on the second conductive type semiconductor layer 140, a first electrode 150 disposed on the first conductive type semiconductor layer 120, and the light-transmitting electrode layer 185 ), and an insulating layer disposed under the second electrode adjacent to the first electrode.

The substrate 110 may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate. For example, the substrate 110 is sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ At least one of can be used.

A buffer layer 181 may be disposed on the substrate 110.

The buffer layer 181 serves to alleviate lattice mismatch between the material of the light emitting structure and the substrate 110. The buffer layer 181 may be formed of at least one of a group III-5 compound semiconductor, such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. The buffer layer 181 may be formed on the substrate 110 at regular intervals to form a plurality of pattern portions.

A first conductivity type semiconductor layer 120 may be disposed on the buffer layer 181.

The first conductivity-type semiconductor layer 120 may include, for example, an n-type semiconductor layer. The first conductivity type semiconductor layer 120 may be implemented as a compound semiconductor. The first conductivity-type semiconductor layer 120 may be implemented as, for example, a Group II-VI compound semiconductor or a Group III-V compound semiconductor.

The first conductivity type semiconductor layer 120 is 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) Can be implemented. The first conductivity type semiconductor layer 120 may be selected from, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, etc., and Si, Ge, Sn, An n-type dopant such as Se or Te may be doped.

The current diffusion layer 182 may improve light efficiency by improving internal quantum efficiency, and may be an undoped gallium nitride layer. An electron injection layer (not shown) may be further formed on the current diffusion layer 182. The electron injection layer may be a conductive gallium nitride layer. For example, since the electron injection layer is doped with an n-type doping element at a concentration of 6.0x10 ¹⁸ atoms/cm ³ to 3.0x10 ¹⁹ atoms/cm ³ , electron injection can be efficiently performed.

A strain control layer 183 may be formed on the electron diffusion layer 182.

The strain control layer 183 effectively relieves an odd stress due to lattice mismatch between the first conductivity type semiconductor layer 120 and the active layer 130.

The lattice constant of the strain control layer 183 may be greater than the lattice constant of the first conductivity type semiconductor layer 120, but less than the lattice constant of the active layer 130. Accordingly, stress due to a difference in lattice constant between the active layer 130 and the first conductivity type semiconductor layer 120 can be minimized.

The strain control layer 183 is a multi-layer (multi-layer) may be formed of, for example, a strain control layer 183 is _{Al x In y Ga 1 -x- y} N and a pair (pair), a plurality of GaN Can be equipped.

An active layer 130 may be disposed on the strain control layer 183.

In the active layer 130, electrons (or holes) injected through the first conductivity type semiconductor layer 120 and holes (or electrons) injected through the second conductivity type semiconductor layer 140 meet each other, and the active layer It is a layer that emits light by a difference in the band gap of the energy band according to the forming material of (130). The active layer 130 may be formed in any one of a single well structure, a multiple well structure, a quantum dot structure, or a quantum wire structure, but is not limited thereto.

The active layer 130 may be a layer that generates ultraviolet rays. The active layer 130 may generate deep ultraviolet light having a wavelength of 170 nm to 210 nm. This is not limited.

The active layer 130 may be implemented as a compound semiconductor. The active layer 130 may be implemented as a group II-VI or III-V compound semiconductor, for example. The active layer 130 may be implemented as 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), for example. have. When the active layer 130 is implemented in the multi-well structure, the active layer 130 may be implemented by stacking a plurality of well layers and a plurality of barrier layers, for example, the InGaN well layer/GaN barrier layer. It can be implemented in cycles.

An electron blocking layer 184 may be disposed on the active layer 130.

The electron blocking layer 184 serves as electron blocking and MQW cladding of the active layer, thereby improving luminous efficiency. The electron blocking layer 184 may be formed of an Al _x In _y Ga _(1-xy) N (0≤x≤1,0≤y≤1) semiconductor, and is higher than the energy band gap of the active layer 130. It may have an energy band gap, and may be formed to a thickness of about 100Å to about 600Å, but is not limited thereto. Alternatively, the electron blocking layer 184 may be formed of an Al _z Ga _(1-z) N/GaN (0≦z≦1) superlattice.

A second conductivity type semiconductor layer 140 may be disposed on the electron blocking layer 184.

The second conductivity-type semiconductor layer 140 may be implemented as, for example, a p-type semiconductor layer. The second conductivity type semiconductor layer 140 may be implemented as a compound semiconductor. The second conductivity-type semiconductor layer 140 may be implemented as, for example, a Group II-VI compound semiconductor or a Group III-V compound semiconductor.

The second conductivity type semiconductor layer 140 is 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) Can be implemented. The second conductivity type semiconductor layer 140 may be selected from, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, etc., and Mg, Zn, Ca, A p-type dopant such as Sr or Ba may be doped.

Meanwhile, the first conductivity-type semiconductor layer 120 may include a p-type semiconductor layer, and the second conductivity-type semiconductor layer 140 may include an n-type semiconductor layer. In addition, a semiconductor layer including an n-type or p-type semiconductor layer may be further formed under the second conductivity-type semiconductor layer 140. Accordingly, the light emitting structure may have at least one of an np, pn, npn, and pnp junction structure.

Doping concentrations of impurities in the first conductivity-type semiconductor layer 120 and the second conductivity-type semiconductor layer 140 may be uniformly or non-uniformly formed. That is, the structure of the light emitting structure may be formed in various ways, but is not limited thereto.

A translucent electrode layer 185 may be disposed on the second conductivity type semiconductor layer 140.

The light-transmitting electrode layer 185 may be multi-stacked on a single metal, a metal alloy, or a metal oxide so that carrier injection can be performed efficiently. For example, the light-transmitting electrode layer 185 may be formed of a material having excellent electrical contact with a semiconductor, and the light-transmitting electrode layer 185 may include indium tin oxide (ITO), indium zinc oxide (IZO), and indium zinc tin oxide (IZTO). , IAZO(indium aluminum zinc oxide), IGZO(indium gallium zinc oxide), IGTO(indium gallium tin oxide), AZO(aluminum zinc oxide), ATO(antimony tin oxide), GZO(gallium zinc oxide), IZON(IZO Nitride) ), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx/ITO, Ni/IrOx/Au, and Ni/IrOx/Au/ITO, Ag, Ni, Cr , Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, may be formed by including at least one of Hf, but is not limited to these materials.

The second electrode 160 is disposed on the light-transmitting electrode layer 185, and the first electrode 150 is formed on the first conductivity type semiconductor layer 120 where the upper portion is exposed. The first electrode 150 may be disposed to surround the second electrode 160. Thereafter, as the first electrode 160 and the second electrode 160 are finally connected to each other, manufacturing of the light emitting device may be completed.

The first electrode 150 and the second electrode 160 are aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), platinum (Pt), gold (Au), tungsten (W), and copper. It may include one or an alloy thereof selected from the group consisting of (Cu) and molybdenum (Mo).

An insulating layer 170 may be disposed between the translucent electrode layer 185 and the second electrode 160.

The insulating layer 170 may be disposed under the second electrode 160 adjacent to the first electrode 150. The insulating layer 170 may be disposed along the lower edge of the second electrode 160. The insulating layer 170 may be disposed to be in contact with the lower edge of the second electrode 160. The second electrode 160 may have a structure covering the insulating layer 170. The insulating layer 170 may be disposed along the edge of the translucent electrode layer 185. The lower central region of the second electrode 160 may be disposed to contact the light-transmitting electrode layer 185.

Alternatively, the insulating layer 170 may be disposed under the translucent electrode layer 185. The insulating layer 170 may be disposed on the second conductivity type semiconductor layer 140. The insulating layer 170 may be disposed along the edge of the second conductivity type semiconductor layer 140.

Also, the light-transmitting electrode layer 185 may be omitted. When the translucent electrode layer 185 is omitted, the insulating layer 170 may be disposed on the second conductivity type semiconductor layer 140. The insulating layer 170 may be disposed along the edge of the second conductivity type semiconductor layer 140.

The insulating layer 170 may include SiO ₂ and Al ₂ O ₃ . The insulating layer 170 may include a material having thermal conductivity. The insulating layer 170 may include a material having a band gap of 5 eV or more. The thickness of the insulating layer 170 may be 1/10 to 1/2 of the thickness of the second electrode 160. The insulating layer 170 may be formed as thin as possible so that current does not flow.

As shown in FIG. 2, the current moves downward from the second electrode 160. Since the insulating layer 170 is disposed at the lower edge of the second electrode 160, the current is not concentrated to the edge of the second electrode 160 and is spread evenly within the second electrode 160. The current evenly diffused within the second electrode 160 is evenly transmitted to the active layer 130 to emit full light.

As described above, by forming the insulating layer 170 under the second electrode 160 adjacent to the first electrode 150, the current at the edge of the second electrode 160 adjacent to the first electrode 150 It is possible to prevent the local concentration of, and from this, it is possible to reduce the phenomenon that only the edge is intensively emitted.

Therefore, the insulating layer structure as described above has an effect of extending the life of the device. In addition, there is an effect of improving the amount of light by 10% or more.

3 is a cross-sectional view showing an ultraviolet light-emitting device according to a second embodiment, and FIG. 4 is a cross-sectional view showing a current movement of the ultraviolet light-emitting device according to the second embodiment.

Referring to FIG. 3, the ultraviolet light emitting device according to the second embodiment includes a substrate 210, a buffer layer 281 disposed on the substrate 210, and a first conductivity type disposed on the buffer layer 281. A semiconductor layer 220, a current diffusion layer 282 disposed on the first conductivity type semiconductor layer 220, a strain control layer 283 disposed on the current diffusion layer 282, and the strain control layer An active layer 230 disposed on 283, an electron blocking layer 284 disposed on the active layer 230, and a second conductivity type semiconductor layer 240 disposed on the electron blocking layer 284 And, a light-transmitting electrode layer 285 disposed on the second conductive type semiconductor layer 240, a first electrode 250 disposed on the first conductive type semiconductor layer 220, and the light-transmitting electrode layer 285 ), and an insulating layer 270 disposed under the second electrode 260 adjacent to the first electrode 250. Here, components except for the structures of the first electrode 250 and the insulating layer 170 are the same as those of the light emitting device according to the first embodiment, and thus are omitted.

The first electrode 250 may be disposed on the first conductivity type semiconductor layer 220 in which the upper portion is exposed. The first electrode 250 may be disposed on one side of the second electrode 260.

The insulating layer 270 may be disposed under the second electrode 260 adjacent to the first electrode 250. The insulating layer 270 may be disposed to be in contact with a lower side of the second electrode 260 adjacent to the first electrode 250. The insulating layer 270 may be disposed on one side of the translucent electrode layer 285. The other side of the second electrode 260 may be disposed to come into contact with the translucent electrode layer 285. When the light-transmitting electrode layer 285 is omitted, the insulating layer 270 may be disposed to contact the second conductivity type semiconductor layer 240.

The insulating layer 270 may include SiO ₂ and Al ₂ O ₃ . The insulating layer 270 may include a material having thermal conductivity. The insulating layer 270 may include a material having a band gap of 5 eV or more. The insulating layer 270 may have a thickness of 1/10 to 1/2 of the second electrode 260. The insulating layer 270 may be formed as thin as possible so that no current flows.

As shown in FIG. 4, the current moves downward from the second electrode 260. Since the insulating layer 270 is disposed on one side of the lower edge of the second electrode 260, the current is not concentrated to the edge of the second electrode 260 and is spread evenly within the second electrode 260. The current evenly diffused within the second electrode 260 is evenly transmitted to the active layer 230 through the other lower side of the second electrode 260 to emit full light.

5 is a cross-sectional view illustrating a package of a flip chip light emitting device including a light emitting device according to embodiments. Here, the light emitting device package may be a flip chip type light emitting device package.

The light emitting device package 300 includes a submount substrate 310, bonding pads 320 and 330 disposed on the submount substrate 310, and a flip chip on the submount substrate 310 by bumps 340 and 350. It may include a light emitting device to be bonded.

The light emitting device 100 may be a light emitting device according to embodiments, and may be disposed on the submountain substrate 310 with the light emitting device 100 turned upside down.

As the submountain substrate 310, SiC, Si, Ge, SiGe, AlN, metal, etc. having excellent thermal conductivity may be used. Bonding pads 320 and 330 may be disposed on the submountain substrate 310. The bonding pads 320 and 330 supply power to the light emitting device 110.

The bonding pads 320 and 330 may use a metal having excellent electrical conductivity, and may be formed through a screen printing method or a deposition process using a mask pattern. The bonding pads 320 and 330 may include a first bonding pad 320 and a second bonding pad 330. The first bonding pad 320 and the second bonding pad 330 may be electrically separated. The first bonding pad 320 may be disposed in a central area on the submountain substrate 310. The second bonding pad 330 may be disposed along the edge of the submounted substrate 310. The second bonding pad 330 may be disposed to surround the first bonding pad 320.

Bumps 340 and 350 may be disposed on the bonding pads 320 and 330. As the bumps 340 and 350, at least one of Pb, Sn, Au, Ge, Cu, Bi, Cd, Zn, Ag, Ni, and Ti may be used, and an alloy thereof may be used. The bumps 340 and 350 may include a first bump 340 and a second bump 350.

The first bump 340 and the second bump 350 may be disposed on the bonding pads 320 and 330 to be electrically connected to the first electrode and the second electrode of the light emitting device 100.

Although described above with reference to the drawings and embodiments, those skilled in the art will understand that the embodiments can be variously modified and changed without departing from the technical spirit of the embodiments described in the following claims. I will be able to.

110: substrate 120: first conductivity type semiconductor layer
130: active layer 140: second conductivity type semiconductor layer
150: first electrode 160: second electrode
170: insulating layer 181: buffer layer

Claims (9)

Board;
A first conductivity type semiconductor layer disposed on the substrate;
An active layer disposed on the first conductivity type semiconductor layer;
A second conductivity type semiconductor layer disposed on the active layer;
A translucent electrode layer disposed on the second conductivity type semiconductor layer;
A second electrode disposed on the translucent electrode layer;
A first electrode disposed on the first conductivity type semiconductor layer so as to be disposed outside the second electrode; And
Including an insulating layer disposed between the translucent electrode layer and the second electrode,
The translucent electrode layer includes at least one of a single metal, a metal alloy, and a metal oxide,
The insulating layer is disposed along a lower edge region of the second electrode,
The insulating layer is in direct contact with an upper surface of the translucent electrode layer and a lower surface of the second electrode and is spaced apart from the second conductivity type semiconductor layer,
The second electrode is in direct contact with a portion of the upper surface of the translucent electrode layer,
The thickness of the insulating layer is 1/10 to 1/2 of the thickness of the second electrode,
The insulating layer is an ultraviolet light emitting device comprising a material having an energy band gap of 5 eV or more. delete delete The method of claim 1,
The first electrode is an ultraviolet light emitting device disposed to surround the second electrode. delete delete The method of claim 1,
The insulating layer is a UV light emitting device including SiO ₂ , Al ₂ O ₃ . delete A light emitting device package comprising the ultraviolet light emitting device according to any one of claims 1, 4 and 7.

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