KR101662239B1 - A light emitting device, a method of fabricating the light emitting device, and a light emitting device package - Google Patents

Abstract

The light emitting device includes a first conductive semiconductor layer, an active layer, a second conductive semiconductor layer, and a first transparent conductive layer sequentially laminated on a substrate, and the first conductive semiconductor layer is etched to expose a part of the first conductive semiconductor layer, A first electrode formed on a dielectric layer formed on one side of the light emitting structure, and a second light transmitting conductive layer formed on a dielectric layer formed on the upper and the other side of the light emitting structure, .

Description

[0001] The present invention relates to a light emitting device, a method of manufacturing the same, and a light emitting device package,

Embodiments relate to a light emitting device, a method of manufacturing the same, and a light emitting device package capable of preventing deterioration of an ambient light and improving ESD resistance.

2. Description of the Related Art Generally, a light emitting diode (LED) is used to convert an electric signal into an infrared ray, a visible ray, or a light by using a characteristic of a compound semiconductor called an electron-hole recombination, Semiconductor device.

In general, LEDs are used for home appliances, remote controls, display boards, displays, various automation devices, and optical communication. The types of LEDs are divided into IRED (Infrared Emitting Diode) and VLED (Visible Light Emitting Diode).

In the LED, the frequency (or wavelength) of the emitted light is a function of the band gap of the semiconductor material. When a semiconductor material having a small band gap is used, photons of low energy and long wavelength are generated, When a semiconductor material having a bandgap is used, short wavelength photons are generated. Therefore, the semiconductor material of the device is selected depending on the type of light to be emitted.

For example, AlGaInP materials are used for red LEDs, and silicon carbide (SiC) and Group III nitride-based semiconductors, especially gallium nitride (GaN), are used for blue LEDs.

Embodiments provide a light emitting device, a method of manufacturing the same, and a light emitting device package that can prevent deterioration of an ambient light and improve ESD resistance.

A light emitting device according to an embodiment includes a substrate; The first conductivity type semiconductor layer, the active layer, the second conductivity type semiconductor layer, and the first light-transmitting conductive layer are sequentially stacked on the substrate, and a part of the first conductivity type semiconductor layer and the other part of the first conductivity type semiconductor layer are etched A light emitting structure; A dielectric layer formed on a surface of the light emitting structure; A first electrode formed on a dielectric layer formed on one side of the light emitting structure; And a second transmissive conductive layer formed on the dielectric layer formed on the upper and the other side of the light emitting structure.

A method of manufacturing a light emitting device according to an embodiment includes sequentially laminating a first conductive type semiconductor layer, an active layer, a second conductive type semiconductor layer, and a first light transmitting conductive layer on a substrate, the transparent conductive layer, Forming a light emitting structure that exposes a portion of the first conductivity type semiconductor layer and another portion of the first conductivity type semiconductor layer by etching the conductive type semiconductor layer, the active layer, and the first conductivity type semiconductor layer; Forming a dielectric layer on a part of a surface of the light emitting structure and a dielectric layer formed on side surfaces and an upper surface of the light emitting structure; forming a dielectric layer on the dielectric layer on one side of the light emitting structure and connected to the first light transmitting conductive layer through the dielectric layer; And forming a second transmissive conductive layer on the dielectric layer formed on the upper surface and the other surface of the light emitting structure.

A light emitting device package according to an embodiment includes a package body, a first metal layer and a second metal layer disposed on the package body, the light emitting element mounted on the package body to be electrically connected to the first metal layer and the second metal layer, And a sealing layer surrounding the light emitting device. The light emitting device package may further include a first wire connected to a first electrode formed on a dielectric layer formed on one side of the light emitting structure of the light emitting device.

The light emitting device, the method of manufacturing the same, and the light emitting device package according to the embodiment can improve the light quantity of the light emitting device and protect the active layer from ESD shock.

1 shows a structure of a general nitride-based semiconductor light-emitting device.
2 shows a light emitting device according to an embodiment.
3A to 3F show a method of manufacturing a light emitting device according to an embodiment.
4 is a conceptual diagram for explaining that the light emitting device shown in FIG. 2 protects the active layer from ESD.
5 illustrates a light emitting device package including a light emitting device according to an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. In the description of the embodiments, it is to be understood that each layer (film), region, pattern or structure is formed "on" or "under" a substrate, each layer The terms " on "and " under " encompass both being formed" directly "or" indirectly " In addition, the criteria for above or below each layer will be described with reference to the drawings.

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. Hereinafter, a light emitting device, a manufacturing method thereof, and a light emitting device package according to embodiments will be described with reference to the accompanying drawings.

2 shows a light emitting device 200 according to an embodiment. 2, the light emitting device 200 includes a substrate 210, a first conductive semiconductor layer 220, an active layer 230, a second conductive semiconductor layer 240, and a first transmissive conductive layer 250 A dielectric layer 260, a second transmissive conductive layer 270, a first electrode 285, and a second electrode 280. The light emitting structure 205 includes a light emitting structure 205, At this time, the first conductivity type may be N-type and the second conductivity type may be P-type.

The substrate 210 may be a sapphire substrate. The substrate 210 may be a template substrate on which at least one of a silicon (Si) substrate, a zinc oxide (ZnO) substrate, a nitride semiconductor substrate, or GaN, InGaN, AlGaN and AlInGaN is stacked. The substrate may be a translucent substrate, but is not limited thereto.

The light emitting structure 205 is formed by sequentially stacking a first conductive semiconductor layer 220, an active layer 230, a second conductive semiconductor layer 240, and a first transparent conductive layer 250 on a substrate 210, Lt; / RTI >

For example, the first conductive semiconductor layer 220 may be an N-type semiconductor layer and may be selected from InAlGaN, GaN, AlGaN, InGaN, AlN and InN. ) May be doped. The second conductive semiconductor layer 240 may be selected from InAlGaN, GaN, AlGaN, InGaN, AlN, and InN, and may be doped with a second conductive dopant (e.g., Mg).

The active layer 230 may be formed in a single or multiple quantum well structure. For example, the active layer 230 includes a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) A structure including at least one of a quantum wire structure, a quantum dot structure, a single quantum well structure or a multi quantum well (MQW) structure.

The first light transmitting conductive layer 250 not only reduces the total reflection but also increases light extraction efficiency of light emitted from the active layer 230 to the second conductive semiconductor layer 240 because of its good light transmitting property.

The first light transmitting conductive layer 250 is made of a transparent oxide material having a high transmittance to the light emitting wavelength of the light emitting device 200. For example, ITO (Indium Tin Oxide), TO (Tin Oxide), IZO (Indium Zinc Oxide), ITZO (Indium Tin Zinc Oxide), ZnO ITO can be used.

The light emitting structure 205 includes a second conductive type semiconductor layer 240, an active layer 230, and a first conductive type semiconductor layer 220 on one side of the multilayer structure to expose a portion of the first conductive type semiconductor layer 220, A portion of the first conductive semiconductor layer 220 exposed by etching is referred to as a first etching region.

The light emitting structure 205 may further include a second conductive semiconductor layer 240, an active layer 230, and a first conductive semiconductor layer (not shown) on the other side of the multilayered structure to expose another portion of the first conductive semiconductor layer 220 220 are etched. Hereinafter, another portion of the first conductive semiconductor layer 220 exposed by etching is referred to as a second etching region.

2, the light emitting structure 215 has a structure in which a part of the exposed portion of the first conductive semiconductor layer 220 (the first etching region) and a surface of the other portion (the second etching region) .

The light emitting structure 205 may also have a surface of the first etch region that is horizontal or lower than the surface of the second etch region.

A dielectric layer 260 is formed on the surface of the light emitting structure 205. For example, the dielectric layer 260 is formed on the first etch region, the second etch region, the sides (e.g., one side and the other side) and the top surface of the light emitting structure 205. At this time, the dielectric layer 260 may cover the whole of the first transmissive conductive layer 250.

Here, one side of the light emitting structure 205 refers to a side adjacent to the first etching region, and the other side of the light emitting structure 205 refers to a side adjacent to the second etching region.

In addition, the dielectric layer 260 may have a groove or hole exposing a part of the upper surface of the first transmissive conductive layer 250. For example, a groove or hole may be formed through the dielectric layer 260 to expose a part of the upper surface of the first transmissive conductive layer 250 adjacent to one side of the light emitting structure 205.

At this time, the dielectric layer 260 may be a structure in which a double layer composed of a SiO ₂ layer and a TiO ₂ layer is repeatedly laminated at least twice.

The second transmissive conductive layer 270 may be formed on the dielectric layer 260 covering the upper surface of the light emitting structure 205 and the dielectric layer 260 covering the other surface of the light emitting structure 205. The second transmissive conductive layer 270 may also be formed on the dielectric layer 260 formed on the second etching region adjacent to the other side of the light emitting structure 205. At this time, the second transmissive conductive layer 270 and the first transmissive conductive layer 250 may overlap each other vertically.

The second electrode 280 may be formed on the surface of the second etching region. The second electrode 280 may be formed on the surface of the second etching region where the second transmissive conductive layer 270 is not formed. And a part of the second electrode 280 may be formed so as to cover a part of the second transmissive conductive layer 270.

The first electrode 285 is formed on one side of the light emitting structure 205 and on the dielectric layer 260 formed on the first etching region. The first electrode 285 may be formed in a groove (or a hole) exposing a part of the upper surface of the first transmissive conductive layer 250 adjacent to one side of the light emitting structure 205. The first electrode 285 is connected to the first transparent conductive layer 250 through a groove (or a hole). The second electrode 280 may be a first conductive type electrode and the first electrode 285 may be a second conductive type electrode and each of the second electrode 280 and the first electrode 285 may include chromium / RTI > and / or gold (Au).

The light emitting device shown in FIG. 2 includes a first bonding pad (not shown) formed on the first electrode 285 on one side of the light emitting structure for bonding an external first wire (522 shown in FIG. 5) And a second bonding pad (not shown) formed on the second electrode 280 for bonding an external second wire (524 shown in FIG. 5).

1 shows a structure of a general nitride-based semiconductor light-emitting device. 1, a nitride-based semiconductor light emitting device 100 includes an n-type nitride semiconductor layer 120, an active layer 130, and a p-type nitride semiconductor layer 140 on a sapphire substrate 110, which is a light- ), And an ITO (Indium Tin Oxide) film 150 are sequentially stacked.

The nitride based semiconductor light emitting device 100 is formed on a portion of the n-type nitride semiconductor layer 120 exposed by the p-type electrode 160 formed on the ITO film 150 and the mesa etching And an n-type electrode 170 formed on the n-type electrode. 1, since the p-type electrode 160 absorbs a part of the light generated in the active layer 130, the light amount of the light emitting device 100 is reduced.

However, unlike the structure of the light emitting device 100 shown in FIG. 1, the light emitting device 200 according to the embodiment has a structure in which the first electrode 285 is formed on one side of the light emitting structure 205. Therefore, since the active layer 230 is not present under the first electrode 285, the recombination of the electrons and holes can be prevented, so that the absorption of the light amount in the first electrode 285 can be reduced.

In addition, the light emitting device 200 according to the embodiment has a structure in which the dielectric layer 260 and the first electrode 285 are laminated on a part of the exposed surface of the first conductivity type semiconductor layer 220. Accordingly, the first conductive semiconductor layer 220, the dielectric layer 260, and the first electrode 285 stacked form a first capacitor 292 of a MOS (Metal / SiO ₂ / Semiconductor) structure.

The light emitting device 200 according to the embodiment may further include a first transmissive conductive layer 250, a dielectric layer 260, and a second transmissive conductive layer 270 sequentially stacked on the upper surface of the second conductive semiconductor layer 220, . Thus, the first transparent conductive layer 250, the dielectric layer 260, and the second transparent conductive layer 270 that are stacked form the second capacitor 294.

Therefore, the first capacitor 292 and the second capacitor 294 of the light emitting device according to the embodiment protect the active layer 230 from ESD (Electrostatic Discharge) impact in pulse form. That is, the high-frequency component due to the ESD shock exits through the first capacitor 292 and the second capacitor 294, so that the active layer 230 region can be protected.

4 is a conceptual diagram for explaining that the light emitting device 200 shown in FIG. 2 protects the active layer 230 from ESD.

4, when the light emitting device 200 is expressed in a circuit, each of the first capacitor 292 and the second capacitor 294 is connected in parallel to the light emitting device 410 (e.g., a light emitting diode) Structure. Here, R1 represents a resistance between the light emitting device 410 and the high voltage pulse generating unit 401. [

The high voltage pulse generating unit 401 generates a pulse voltage such as an instantaneous static electricity and applies the generated pulse voltage to the light emitting device 200. For example, the high voltage pulse generating unit 401 includes a high voltage pulse generator 420 for generating a pulse voltage V _ESD 430, a first capacitor Ch for charging a pulse voltage V _ESD or discharging a charged pulse voltage, The resistor R2 existing between the high voltage pulse generator 420 and the first capacitor Ch and the pulse voltage V _ESD generated by the first capacitor Ch or the first capacitor Ch, And a switch 440 for switching to discharge the charged pulse voltage V _ESD to the light emitting device 200. [

The amount of charge Q _Dis charged in the first capacitor Ch by the pulse voltage V _ESD generated from the high voltage pulse generator 420 is expressed by Equation 1.

The total capacitance CT1 of the light emitting device 100 shown in FIG. 1 is expressed by Equation 2, and the total capacitance CT2 of the light emitting device 200 shown in FIG.

Here, C _Diode represents the capacitance of a general luminous element without the MOS capacitor shown in Fig. 1, C _MOS represents the capacitance of the first capacitor 292 shown in Fig. 2, C _cp represents the capacitance of the first capacitor 292 shown in Fig. Lt; RTI ID = 0.0 > 292 < / RTI >

The total capacitance CT2 of the light emitting device 200 according to the embodiment is larger than the total capacitance CT1 of the general light emitting device 100 shown in FIG. 1 (CT2> CT1).

In general, a current (I) flowing in a light emitting device is expressed by Equation (4).

In this case, Q represents a quantity of charge supplied to the light emitting device,? Represents a time constant, R1 represents a resistance of the light emitting device, and CT represents a total capacitance value of the light emitting device. Q _Dis represents the amount of charge applied to the light emitting diode, for example, the amount of charge discharged from the first capacitor Ch to the light emitting element.

Referring to Equation 4, the current flowing through the light emitting element is inversely proportional to the total capacitance CT of the light emitting element.

The current I2 flowing in the light emitting device 200 shown in FIG. 2 is smaller than the current flowing in the light emitting device 100 shown in FIG. 1 when the pulse voltage V _ESD is applied because CT2> CT1. That is, in the light emitting device according to the embodiment, the current flowing to the active layer 230 due to the electrostatic stress is reduced, so that the electrostatic shock can be mitigated.

Also, the embodiment can control the capacitance of the second capacitor by controlling the area of the second transparent conductive layer 365. Therefore, a larger capacitance can be easily manufactured, and ESD can be improved.

3A to 3F show a method of manufacturing a light emitting diode according to another embodiment of the present invention.

3A, a first conductive semiconductor layer 320, an active layer 330, a second conductive semiconductor layer 340, and a first transmissive conductive layer 350 are sequentially formed on a sapphire substrate 310 . For example, an n-type GaN layer 320, an active layer 330 in which a GaN layer and an InGaN layer are stacked, a P-type GaN layer 340, and an ITO layer (Indium Tin Oxide layer) 350 are formed on a sapphire substrate 310 Can be formed sequentially.

3B, the first transparent conductive layer 350, the second conductive semiconductor layer 340, the active layer 330, and the first conductive semiconductor layer 320 are selectively etched in order, Thereby exposing a part of the region A of the first conductivity type semiconductor layer 320. At this time, a portion A of the first conductive semiconductor layer 320 is etched from the active layer 330 to the first depth a. At this time, a portion of the first conductive semiconductor layer 320 exposed by etching is referred to as a first etching region A.

The first conductivity type semiconductor layer 320, the first conductivity type semiconductor layer 340, the active layer 330, and the first conductivity type semiconductor layer 320 are sequentially etched by selectively etching the first light-transmitting conductive layer 350, the second conductivity type semiconductor layer 340, (B). At this time, another portion B of the first conductive semiconductor layer 320 is etched from the active layer 330 to the second depth b. Wherein the first depth (a) is equal to or greater than the second depth (b) (a? B). At this time, another part of the region of the first conductivity type semiconductor layer 320 exposed by the etching is referred to as a second etching region B.

Next, as shown in FIG. 3C, a dielectric layer 360 is formed on the surface of the etched product (hereinafter referred to as "the light emitting structure 305"). The dielectric layer 360 is formed of a SiO ₂ layer and TiO ₂ Layer can be formed by repeatedly laminating at least two double layers.

3D, the dielectric layer 360 is selectively etched so as to have a groove 362 exposing a part of the second etching region B and a part of the upper surface of the first light transmitting conductive layer 350, Lt; / RTI > The dielectric layer 360 is formed on the side surfaces (e.g., one side surface and the other side surface) and the upper surface of the light emitting structure 205, and on some surfaces of the second etching region, A groove 362 is formed to expose a part of the upper surface of the light-transmitting conductive layer 250.

Next, as shown in FIG. 3E, on the dielectric layer 260 formed on part of the upper surface of the light emitting structure 305, the other surface, and a part of the surface of the second etching area B, a second transparent conductive layer 365 ).

For example, an ITO layer may be formed on the surface of the selectively etched dielectric layer 360, and the ITO layer may be selectively etched to be formed on the upper surface, the other surface, and a part of the second etching area B of the light emitting structure 305 The second translucent conductive layer 365 is left on the dielectric layer 360 to be formed. At this time, the second transparent conductive layer 365 may remain in a part of the second etching region adjacent to the other side of the light emitting structure 305.

Next, as shown in FIG. 3F, a second electrode 375 is formed on a part of the exposed surface of the second etching region. The second electrode 375 may be formed on a part of the surface of the second etching region adjacent to the remaining second translucent conductive layer 365 and may cover a part of the second translucent conductive layer 265.

The first electrode 370 is formed in the groove 362 exposing the surface of the dielectric layer 360 formed on one side of the light emitting structure 305 and the upper surface portion of the first light transmitting conductive layer 350.

5 illustrates a light emitting device package including a light emitting device according to an embodiment. Referring to FIG. 5, the light emitting device package includes a package body 510, a first metal layer 512, a second metal layer 514, a light emitting device 520, a first wire 522, a second wire 524, Reflective plate 530 and encapsulant layer 540. [

The package body 510 is a structure in which a cavity is formed in one side region. At this time, the side wall of the cavity may be formed to be inclined. The package body 510 may be formed of a substrate having good insulating or thermal conductivity, such as a silicon based wafer level package, a silicon substrate, silicon carbide (SiC), aluminum nitride (AlN) Or may be a structure in which a plurality of substrates are stacked. The embodiments are not limited to the material, structure, and shape of the body described above.

The first metal layer 512 and the second metal layer 514 are disposed on the surface of the package body 510 so as to be electrically separated from each other in consideration of heat discharge or mounting of the light emitting device. The light emitting device 520 is electrically connected to the first metal layer 512 and the second metal layer 514 through the first wire 522 and the second wire 524.

For example, the first wire 522 electrically connects the first electrode 285 of the light emitting device shown in FIG. 2 and the first metal layer 512, the second wire 524 electrically connects the second electrode 280, The second metal layer 514 may be electrically connected.

The first wire 522 may be connected to a first bonding pad formed on the first electrode 285 and the second wire 524 may be connected to a second bonding pad formed on the second electrode 280. [ have.

5, the first wire 522 is connected to the first electrode 285 (or the first bonding pad) formed on the side surface rather than the upper surface of the light emitting structure, so that the light amount absorption in the first electrode 285 Can be reduced.

The reflection plate 530 is formed on the cavity sidewall of the package body 510 to direct the light emitted from the light emitting element 520 in a predetermined direction. The reflection plate 530 is made of a light reflection material, and may be, for example, a metal coating or a metal flake.

The encapsulation layer 540 surrounds the light emitting device 520 located in the cavity of the package body 510 to protect the light emitting device 520 from the external environment. The sealing layer 540 is made of a colorless transparent polymer resin material such as epoxy or silicone. The sealing layer 540 may include a phosphor to change the wavelength of light emitted from the light emitting device 320. The light emitting device package can mount at least one of the light emitting elements of the above-described embodiments, but is not limited thereto.

A plurality of light emitting device packages according to embodiments may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, and the like may be disposed on the light path of the light emitting device package. The light emitting device package, the substrate, and the optical member may function as a backlight unit.

Still another embodiment may be implemented as a display device, an indicating device, and a lighting system including the light emitting device or the light emitting device package described in the above embodiments. For example, the lighting system may include a lamp and a streetlight.

Since the second conductive type electrode is formed on the side surface of the light emitting structure and the active layer is not present under the second conductive type electrode in the light emitting device according to the embodiment, The light amount of the light emitting device can be reduced and the light amount of the light emitting device can be improved. As described in FIG. 4, the first capacitor and the second capacitor of the light emitting device can protect the active layer from the pulse ESD shock.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

210, 310: substrate, 205, 305:
220, 320: first conductivity type semiconductor layer, 230, 330: active layer,
240,340: a second conductivity type semiconductor layer, 250,350: a first translucent conductive layer,
260, 360: dielectric layer, 270, 365: second light transmitting conductive layer,
280,375: first conductive type electrode, 285,370: second conductive type electrode
510: package body, 512: first metal layer, 514: second metal layer, 520: light emitting element,
522: first wire, 524: second wire, 530: reflector, 540: sealing layer.

Claims (13)

Board;
A first region in which a first conductivity type semiconductor layer, an active layer, a second conductivity type semiconductor layer, and a first transmissive conductive layer are sequentially laminated on the substrate, a part of the first conductivity type semiconductor layer is exposed, A second region that exposes another portion of the one-conductivity-type semiconductor layer;
A dielectric layer formed on a side surface of the light emitting structure and on an exposed surface of the first conductivity type semiconductor layer of the first and second regions of the light emitting structure; And
A first electrode formed on the first region and a dielectric layer formed on one side of the side of the light emitting structure adjacent to the first region;
A second transmissive conductive layer formed on a dielectric layer formed on an upper portion of the light emitting structure and another region on a side surface of the light emitting structure adjacent to the second region; And
And a second electrode formed on an exposed surface of the first conductive type semiconductor layer in the second region,
Wherein an exposed surface of the first conductive type semiconductor layer in the first region is lower than an exposed surface of the first conductive type semiconductor layer in the second region. The method according to claim 1,
Wherein an exposed surface of the first conductive type semiconductor layer of each of the first and second regions is located lower than the active layer. The method according to claim 1,
Wherein the first region is a first etching region in which the light emitting structure is etched,
The second region is a second etching region in which the light emitting structure is etched,
Wherein the first etch region has a first depth from the active layer,
The second etch region having a second depth from the active layer,
Wherein the first depth is greater than the second depth. The method according to claim 1,
Wherein the first light transmitting conductive layer is made of a transparent oxide-based material. 5. The organic electroluminescent device according to claim 4,
A SiO ₂ layer and a TiO ₂ layer is repeatedly laminated at least twice. The plasma display panel of claim 1,
And one end thereof is connected to the first light-transmitting conductive layer through the dielectric layer. The method according to claim 1,
Wherein the first light-transmitting conductive layer and the second light-transmitting conductive layer are an ITO layer (Indium Tin Oxide layer). The method according to claim 1,
And a part of the second electrode is formed so as to cover a part of the second transmissive conductive layer. The dielectric layer according to claim 1,
And a surface of the first transmissive conductive layer is covered. The method according to claim 1,
Wherein the first transmissive conductive layer and the second transmissive conductive layer overlap vertically. A package body;
A first metal layer and a second metal layer disposed in the package body;
The light emitting device according to any one of claims 1 to 10, which is mounted on the package body so as to be electrically connected to the first metal layer and the second metal layer. And
And a sealing layer surrounding the light emitting device. delete delete

Images