KR101172136B1 - Light emitting device, method for fabricating the same and light emitting device package - Google Patents

Abstract

The embodiment relates to a light emitting device, a method of manufacturing the light emitting device, and a light emitting device package.

A light emitting device according to an embodiment includes a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; An insulator on the cavity in which the light emitting structure is partially removed; And a first electrode on the insulator.

Light Emitting Device, Current Diffusion

Description

LIGHT EMITTING DEVICE, METHOD FOR FABRICATING THE SAME AND LIGHT EMITTING DEVICE PACKAGE}

The embodiment relates to a light emitting device, a method of manufacturing the light emitting device, and a light emitting device package.

A light emitting device (LED) may be generated by combining elements of group III and group V on a periodic table of a p-n junction diode having a characteristic in which electrical energy is converted into light energy. LED can realize various colors by adjusting the composition ratio of compound semiconductors.

When the forward voltage is applied, the n-layer electrons and the p-layer holes combine to emit energy corresponding to the energy gap of the conduction band and the valence band. It is mainly emitted in the form of heat or light, and when it is emitted in the form of light, it becomes an LED.

For example, nitride semiconductors are receiving great attention in the field of optical devices and high power electronic devices due to their high thermal stability and wide bandgap energy. In particular, blue light emitting devices, green light emitting devices, and ultraviolet light emitting devices using nitride semiconductors are commercially used and widely used.

In the vertical light emitting device according to the prior art, n-type electrodes and p-type electrodes are formed above and below, respectively, for current injection.

In this case, electrons and holes injected by the n-type electrode and the p-type electrode respectively flow into the active layer to combine to generate light. The generated light is emitted to the outside but a part is reflected by the n-type electrode is lost in the light emitting device. That is, according to the prior art, the light emitted under the n-type electrode has a problem that the luminous efficiency decreases due to the reflection of the n-type electrode.

In addition, according to the prior art, there is a problem that heat is generated by reabsorption of light reflected by the n-type electrode.

In addition, according to the prior art, there is a problem in that the lifetime and reliability due to current crowding is reduced.

Embodiments provide a light emitting device, a method of manufacturing a light emitting device, and a light emitting device package capable of improving current spreading efficiency as well as improving light extraction efficiency.

A light emitting device according to an embodiment includes a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; An insulator on the cavity in which the light emitting structure is partially removed; And a first electrode on the insulator.

In addition, the light emitting device according to the embodiment includes a light emitting structure including a first conductive semiconductor layer, an active layer, a second conductive semiconductor layer; A first electrode on a first insulator formed on the light emitting structure; And a second electrode formed on the light emitting structure, wherein the resistance of the first region below the first electrode is greater than the resistance of the second region below the second electrode.

In addition, the manufacturing method of the light emitting device according to the embodiment comprises the steps of forming a light emitting structure comprising a first conductive semiconductor layer, an active layer, a second conductive semiconductor layer; Removing a portion of the light emitting structure to form a cavity; Forming an insulator on the cavity; And forming a first electrode on the insulator.

In addition, the light emitting device package according to the embodiment includes a light emitting structure, the light emitting device including an insulator on the cavity in which the light emitting structure is partially removed and a first electrode on the insulator; And a package body in which the light emitting device is disposed.

According to the light emitting device, the manufacturing method of the light emitting device, and the light emitting device package according to the embodiment, light extraction efficiency can be increased by controlling the current flow.

In addition, according to the embodiment, the reliability of the light emitting device can be improved by increasing the current spreading efficiency.

In the description of an embodiment according to the present invention, each layer (film), region, pattern or structure is "on / over" or "below" of the substrate, each layer (film), region, pad or patterns. In the case described as being formed under, "on / over" and "under" are formed "directly" or "indirectly" through another layer. It includes everything that is done. In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

(Example)

1 is a cross-sectional view of a light emitting device according to an embodiment.

The light emitting device 100 according to the embodiment includes a light emitting structure 110 including a first conductive semiconductor layer 112, an active layer 114, and a second conductive semiconductor layer 116, and the light emitting structure is partially removed. It may include an insulator 130 formed on the cavity and the first electrode 144 formed on the insulator 130.

The cavity C may be a cavity in which a portion of the first conductivity type semiconductor layer 112 is removed.

The insulator 130 may include a first insulator 132 filling the cavity C and a second insulator 134 formed on the first insulator.

The horizontal width of the second insulator 134 may be wider than the horizontal width of the first insulator 132.

The depth d of the cavity C may be greater than the thickness t2 of the remaining first conductive semiconductor layer.

A third electrode 142 may be included on the light emitting structure 110 on one side of the first electrode 144. The first electrode 144 may be a pad electrode, but is not limited thereto.

In addition, the light emitting device 100 according to the embodiment includes a light emitting structure 110 including a first conductive semiconductor layer 112, an active layer 114, and a second conductive semiconductor layer 116, and the light emitting structure ( A first electrode 144 on the first insulator 134 formed on the 110 and a second electrode 142 formed on the light emitting structure 110, and formed under the first electrode 144. The resistance of the first region may be greater than the resistance of the second region under the second electrode 142.

The embodiment further includes a second insulator 132 formed under the first insulator 134, and the second insulator 132 has a depth direction inside the first conductive semiconductor layer 112. It can be formed as.

The second insulator 132 may have a larger thickness than the remaining first conductive semiconductor layer 112.

The first electrode 144 may be a pad electrode.

In the light emitting structure 110, the first conductivity-type semiconductor layer 112, for example, N-GaN, has high ionization concentration and conductivity, and thus, current is easily spread. However, this has a problem in that a considerable amount of light absorbed under the pad electrode is absorbed by the pad electrode to reduce light extraction.

According to an embodiment, the first conductive semiconductor layer under the pad electrode may be partially etched, and then an insulator is deposited to form a pad electrode. As a result, the remaining region of the first conductivity-type semiconductor layer 112 has a low thickness t2, so that a resistance higher than that of the unetched first conductivity-type semiconductor layer 112 is generated. Accordingly, current flows under the pad electrode. By increasing the current diffusion in the region other than the pad electrode, the current density is increased in the region other than the pad electrode, thereby improving the overall light extraction efficiency.

Further, according to the embodiment, the insulating layer is filled in the cavity from which the first conductivity type semiconductor layer is removed to block the flow of current in the area under the pad electrode to suppress the generation of light in the active layer under the pad electrode. Can reduce the absorption of light.

2 and 3 are diagrams showing light emission characteristics of the light emitting device according to the embodiment.

2 is a diagram of light emitting power according to an etching depth d of the light emitting structure 110, that is, a depth d of the cavity C. For example, FIG. 2 is a first conductivity type semiconductor. When the total thickness t1 of the layer 112 is 4 μm, for example, it is a plot of output power according to the etching depth d. In FIG. 2, the first comparative example R1 is a case where the light emitting structure is not etched (d = 0).

Referring to FIG. 2, the deeper the etching depth d, the higher the output power.

3 is a ratio of light extraction efficiency with the second comparative example R2 according to the thickness t2 of the first conductive semiconductor layer 112 remaining. For example, when the total thickness t1 of the first conductivity type semiconductor layer 112 is 4 μm, the thickness t2 of the remaining first conductivity type semiconductor layer 112 is 0.001 μm, 0.01 μm, and 0.1 μm, respectively. And a light extraction efficiency ratio in the case of 1.0 μm (based on the X axis).

In the second comparative example R2, for example, when the total thickness t1 of the first conductivity-type semiconductor layer 112 is 4 μm, the thickness t2 of the remaining first conductivity-type semiconductor layer is 1 μm. Is an example.

According to the embodiment, when the thickness of the remaining first conductivity-type semiconductor layer 112 is, for example, about 0.01 μm or less, the relative light extraction efficiency is remarkably increased.

In example embodiments, the light extraction efficiency may increase as the depth d of the cavity C is greater than the thickness t2 of the remaining first conductive semiconductor layer.

According to the light emitting device, the manufacturing method of the light emitting device, and the light emitting device package according to the embodiment, light extraction efficiency can be increased by controlling the current flow.

In addition, according to the embodiment, the reliability of the light emitting device may be improved by current spreading.

Hereinafter, a method of manufacturing a light emitting device according to an embodiment will be described with reference to FIGS. 4 to 8.

First, as shown in FIG. 4, the first substrate 105 is prepared. The first substrate 105 may be a sapphire (Al ₂ O ₃ ) substrate, a SiC substrate and the like, but is not limited thereto. Impurities on the surface may be removed by wet cleaning the first substrate 105.

Thereafter, a light emitting structure 110 including a first conductivity type semiconductor layer 112, an active layer 114, and a second conductivity type semiconductor layer 116 is formed on the first substrate 105.

The first conductive semiconductor layer 112 may form an N-type GaN layer using a chemical vapor deposition method (CVD), molecular beam epitaxy (MBE), or sputtering or hydroxide vapor phase epitaxy (HVPE). . In addition, the first conductive semiconductor layer 112 may include a silane containing n-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and silicon (Si). The gas SiH ₄ may be injected and formed.

In this embodiment, an undoped semiconductor layer (not shown) may be formed on the first substrate 105, and a first conductivity-type semiconductor layer 112 may be formed on the undoped semiconductor layer. . For example, an undoped GaN layer may be formed on the first substrate 105, and an n-type GaN layer may be formed to form the first conductive semiconductor layer 112.

Thereafter, an active layer 114 is formed on the first conductivity type semiconductor layer 112. The active layer 114 has an energy band inherent in the active layer (light emitting layer) material because electrons injected through the first conductive semiconductor layer 112 and holes injected through the second conductive semiconductor layer 116 formed thereafter meet each other. It is a layer that emits light with energy determined by.

The active layer 114 may have a quantum well structure in which nitride semiconductor thin film layers having different energy bands are alternately stacked one or more times. For example, the active layer 114 is injected with trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) to form an InGaN / GaN, InGaN / InGaN structure. The multi quantum well structure may be formed, but is not limited thereto.

Thereafter, a second conductive semiconductor layer 116 is formed on the active layer 114. For example, the second conductive semiconductor layer 116 includes p-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and magnesium (Mg) in the chamber. Bicetyl cyclopentadienyl magnesium (EtCp ₂ Mg) {Mg (C ₂ H ₅ C ₅ H ₄ ) ₂ } is injected to form a p-type GaN layer, but is not limited thereto.

Next, as shown in FIG. 5, the second electrode layer 120 is formed on the light emitting structure 110. For example, the second electrode layer 120 may be formed on the second conductive semiconductor layer 116, but is not limited thereto.

The second electrode layer 120 may include an ohmic layer (not shown), a reflective layer 122, a bonding layer (not shown), a conductive layer 124, and the like. The second electrode layer 120 is a semiconductor substrate in which titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), or impurities are implanted. It may be formed of at least one of.

For example, the second electrode layer 120 may include an ohmic layer, and may be formed by stacking a single metal, a metal alloy, a metal oxide, or the like in multiple layers to efficiently inject holes. For example, the ohmic layer may include ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx. At least one of RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, but is not limited thereto.

In addition, when the second electrode layer 120 includes the reflective layer 122, the second electrode layer 120 may be formed of a metal layer including Al, Ag, or an alloy including Al or Ag. Aluminum or silver can effectively reflect the light generated from the active layer to greatly improve the light extraction efficiency of the light emitting device.

In addition, when the second electrode layer 120 includes a bonding layer, the reflective layer may function as a bonding layer or form a bonding layer using nickel (Ni), gold (Au), or the like.

In addition, the second electrode layer 120 may include a conductive layer 124. If the first conductivity type semiconductor layer 112 is sufficiently thick (50 μm or more), the process of forming the conductive layer may be omitted. The conductive layer 124 may be made of a metal, a metal alloy, or a conductive semiconductor material having excellent electrical conductivity to inject holes efficiently. For example, the conductive layer 124 may be copper (Cu), copper alloy (Cu Alloy) or Si, Mo, SiGe and the like. The conductive layer 124 may be formed using an electrochemical metal deposition method or a bonding method using a eutectic metal.

Next, as illustrated in FIG. 6, the first substrate 105 is removed to expose the first conductivity-type semiconductor layer 112. The method of removing the first substrate 105 may use a high power laser to separate the first substrate or use a chemical etching method. In addition, the first substrate 105 may be removed by physically grinding. The removal of the first substrate exposes the first conductivity type semiconductor layer 112 or the undoped semiconductor layer.

Next, as shown in FIG. 7, a portion of the light emitting structure 110 is removed to form a cavity C. For example, the cavity C may be formed by partially removing the first conductivity-type semiconductor layer 112, but is not limited thereto. The cavity C may include a recess, a groove, a trench, a trench, and the like.

For example, etching may be performed on a portion of the first conductivity-type semiconductor layer 112 corresponding to the vertical bottom of the first electrode 144 to be formed later. The etching for forming the cavity C may be performed by dry etching or wet etching.

According to the embodiment, since the current is not smoothly supplied to the region where the cavity C is formed, light emission does not occur below the cavity C, and accordingly, the first electrode 144 existing above the cavity C. The absorption of light by) can be minimized.

Next, an insulator 130 is formed on the cavity C as shown in FIG. 8. For example, the insulator 130 may be formed on the cavity C by using an oxide film such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , SiN, or a nitride film.

Forming the insulator 130 includes forming a first insulator 132 filling the cavity C and forming a second insulator 134 on the first insulator 132. can do. The first insulator 132 and the second insulator 134 may be formed of the same material or different materials.

For example, a first insulator 132 filling the cavity C is formed. For example, the first insulator 131 filling the cavity C is formed using an oxide film such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , SiN, or a nitride film.

Thereafter, a second insulator 134 may be formed on the first insulator 132. For example, the second insulator 134 may be formed through patterning after forming an insulating material on the light emitting structure 110 including the first insulator 132, but is not limited thereto.

At this time, in an embodiment, the horizontal width of the second insulator 134 may be wider than the horizontal width of the first insulator 132, but is not limited thereto. Accordingly, the first electrode 144 formed afterwards is prevented from directly contacting the light emitting structure 110, and thus, electrons supplied from the pad electrode do not flow directly into the light emitting structure below the pad electrode, but instead of the third electrode around the pad electrode. Current spreading may be achieved by flowing through the electrode 142.

Meanwhile, according to the exemplary embodiment, the third electrode 142 may be formed on the light emitting structure 110 on one side of the first electrode 144, and the third electrode 142 may be formed at the same time as the first electrode 144 forming process. It may proceed, but is not limited to such.

In an embodiment, the first electrode 144 may be formed on the insulator 130 so as to spatially overlap the cavity C. In the embodiment, the cavity C region below the vertical of the first electrode 144 is not smoothly supplied with current, and thus no light is generated by the combination of carriers (electrons and holes).

In addition, the cavity C, which is an etched region in the embodiment, is covered with the insulator 130 so that current does not flow, but current is diffused to other regions. In other words, the cavity is covered with an insulator and serves as a current blocking layer (CBL). Therefore, it is possible to minimize the absorption of light by the first electrode as well as to improve reliability by efficient current flow, thereby increasing the amount of light.

According to the light emitting device, the manufacturing method of the light emitting device, and the light emitting device package according to the embodiment, light extraction efficiency can be increased by controlling the current flow.

Further, according to the embodiment, the reliability of the light emitting device can be improved by current spreading.

9 is a view illustrating a light emitting device package in which a light emitting device is installed, according to embodiments.

Referring to FIG. 9, the light emitting device package according to the embodiment may include a body part 200, a fifth electrode layer 210 and a fourth electrode layer 220 installed on the body part 200, and the body part 200. The light emitting device 100 is installed at and electrically connected to the fifth electrode layer 210 and the fourth electrode layer 220, and a molding member 400 surrounding the light emitting device 100 is included.

The body part 200 may include a silicon material, a synthetic resin material, or a metal material, and an inclined surface may be formed around the light emitting device 100.

The fifth electrode layer 210 and the fourth electrode layer 220 are electrically separated from each other, and serve to provide power to the light emitting device 100. In addition, the fifth electrode layer 210 and the fourth electrode layer 220 may serve to increase light efficiency by reflecting the light generated from the light emitting device 100, and generated from the light emitting device 100. It may also serve to release heat to the outside.

The light emitting device 100 may be a vertical type light emitting device illustrated in FIG. 1, but is not limited thereto.

The light emitting device 100 may be installed on the body portion 200 or may be installed on the fifth electrode layer 210 or the fourth electrode layer 220.

The light emitting device 100 may be electrically connected to the fifth electrode layer 210 and / or the fourth electrode layer 220 through a wire 300. In this embodiment, the vertical light emitting device 100 is illustrated. As such, one wire 300 is used. As another example, when the light emitting device 100 is a horizontal type light emitting device, two wires 300 may be used. When the light emitting device 100 is a flip chip type light emitting device, the wire 300 may be used. May not be used.

The molding member 400 may surround the light emitting device 100 to protect the light emitting device 100. In addition, the molding member 400 may include a phosphor to change the wavelength of the light emitted from the light emitting device 100.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. And differences relating to such modifications and applications will have to be construed as being included in the scope of rights specified in the appended claims.

1 is a cross-sectional view of a light emitting device according to an embodiment.

2 and 3 are light emission characteristics of the light emitting device according to the embodiment.

4 to 8 are cross-sectional views of a method of manufacturing a light emitting device according to the embodiment.

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

Claims (20)

A light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; An insulator on the cavity in which the light emitting structure is partially removed; And A pad electrode disposed to correspond to the insulator; A lower side of the insulator is located above the active layer, The cavity is a cavity in which only a part of the first conductivity type semiconductor layer of the light emitting structure is removed. The thickness of the cavity is greater than the thickness of the first conductive semiconductor layer remaining after the portion of the first conductive semiconductor layer is removed. Light emitting element. delete The method according to claim 1, The insulator is, A first insulator filling the cavity; And And a second insulator on the first insulator. The method of claim 3, And a horizontal width of the second insulator is wider than a horizontal width of the first insulator. The method according to claim 1, When the total thickness of the first conductive semiconductor layer is 4㎛, the thickness of the remaining first conductive semiconductor layer is 0.01㎛ or less. The method according to claim 1, Light emitting device comprising an electrode on the light emitting structure on one side of the pad electrode. delete Forming a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; Removing a portion of the light emitting structure to form a cavity; Forming an insulator on the cavity; And And forming a pad electrode to correspond to the insulator. A lower side of the insulator is located above the active layer, The cavity is a cavity in which only a part of the first conductivity type semiconductor layer of the light emitting structure is removed. The thickness of the cavity is greater than the thickness of the first conductive semiconductor layer remaining after the portion of the first conductive semiconductor layer is removed. delete The method of claim 8, Forming the insulator, Forming a first insulator that fills the cavity; And Forming a second insulator on the first insulator; manufacturing method of a light emitting device comprising a. The method of claim 10, And the horizontal width of the second insulator is wider than the horizontal width of the first insulator. The method of claim 8, If the total thickness of the first conductive semiconductor layer is 4㎛, the thickness of the remaining first conductive semiconductor layer is 0.01㎛ or less manufacturing method of the light emitting device. The method of claim 8, When the pad electrode is formed, A method of manufacturing a light emitting device to form an electrode together on the light emitting structure. A light emitting device including a light emitting structure including a first conductive semiconductor layer and an active layer and a second conductive semiconductor layer, an insulator on a cavity from which the light emitting structure is partially removed, and a pad electrode disposed to correspond to the insulator; And And a package body in which the light emitting device is disposed. A lower side of the insulator is located above the active layer, The cavity is a cavity in which only a part of the first conductivity type semiconductor layer of the light emitting structure is removed. The thickness of the cavity is greater than the thickness of the first conductive semiconductor layer remaining after the portion of the first conductive semiconductor layer is removed. 15. The method of claim 14, When the total thickness of the first conductive semiconductor layer is 4㎛, the thickness of the remaining first conductive semiconductor layer is 0.01㎛ or less. 15. The method of claim 14, The insulator is, A first insulator filling the cavity; And And a second insulator on the first insulator. A light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; A first insulator formed on the cavity in which the light emitting structure is partially removed, and a pad electrode disposed to correspond to the first insulator; And An electrode formed on the light emitting structure; The resistance of the first region below the pad electrode is greater than the resistance of the second region below the electrode, A lower side of the second insulator formed under the first insulator is located on the active layer, The cavity is a cavity in which only a part of the first conductivity type semiconductor layer of the light emitting structure is removed. The thickness of the second insulator formed in the cavity is greater than the thickness of the first conductive semiconductor layer remaining after the portion of the first conductive semiconductor layer is removed. Light emitting element. 18. The method of claim 17, The second insulator is formed in the depth direction inside the first conductivity type semiconductor layer. 19. The method of claim 18, When the total thickness of the first conductive semiconductor layer is 4㎛, the thickness of the remaining first conductive semiconductor layer is 0.01㎛ or less. delete

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