KR20090080217A - Nitride light emitting device - Google Patents

Abstract

A nitride-based light emitting device is provided to improve an optical extraction effect by forming a phosphor layer and an electrode in patterns. A nitride-based light emitting device includes a reflective layer(40), a first electrode(20), a semiconductor layer(10), a second electrode, and a phosphor layer(60). The first electrode is positioned on the reflective layer. The semiconductor layer is positioned on the first electrode. The second electrode is positioned on the semiconductor layer. The phosphor layer is positioned on a part except for the second electrode on the semiconductor layer. The phosphor layer is formed to change a wavelength of the light emitted from the semiconductor layer. The reflective layer is positioned on a supporting layer(50) which is composed of a metal or a semiconductor.

Description

Nitride-based light emitting device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitride based light emitting device, and more particularly, to a nitride based light emitting device capable of providing a light emitting device that emits a variety of colors and improving color conversion efficiency and reliability of the light emitting device.

Light Emitting Diodes (LEDs) are well-known semiconductor light emitting devices that convert current into light.In 1962, red LEDs using GaAsP compound semiconductors were commercialized, along with GaP: N series green LEDs. It has been used as a light source for display images of electronic devices, including.

The wavelength of light emitted by such LEDs depends on the semiconductor material used to make the LEDs. This is because the wavelength of the emitted light depends on the band-gap of the semiconductor material, which represents the energy difference between the valence band electrons and the conduction band electrons.

Gallium nitride compound semiconductors (Gallium Nitride (GaN)) have high thermal stability and wide bandgap (0.8 to 6.2 eV), which has attracted much attention in the development of high-power electronic components including LEDs.

One reason for this is that GaN can be combined with other elements (indium (In), aluminum (Al), etc.) to produce semiconductor layers that emit green, blue and white light.

In this way, the emission wavelength can be adjusted to match the material's characteristics to specific device characteristics. For example, GaN can be used to create white LEDs that can replace incandescent and blue LEDs that are beneficial for optical recording.

Due to the advantages of these GaN-based materials, the GaN-based LED market is growing rapidly. Therefore, since commercial introduction in 1994, GaN-based optoelectronic device technology has rapidly developed.

The brightness or output of the LED using the GaN-based material as described above is large, the structure of the active layer, the light extraction efficiency to extract light to the outside, the size of the LED chip, the type and angle of the mold (mold) when assembling the lamp package , Fluorescent material and the like.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a nitride-based light emitting device capable of providing a light emitting device capable of efficiently performing color conversion by a phosphor in a chip unit.

As a first aspect for achieving the above technical problem, the present invention provides a nitride-based light emitting device comprising: a reflective layer; A first electrode on the reflective layer; A semiconductor layer on the first electrode; A second electrode on the semiconductor layer; And a phosphor layer positioned on a portion other than the second electrode on the semiconductor layer to convert wavelengths of light emitted from the semiconductor layer.

As a second aspect for achieving the above technical problem, the present invention provides a nitride-based light emitting device comprising: a reflective layer; A first phosphor layer positioned on the reflective layer; A substrate positioned on the first phosphor layer; A semiconductor layer on the substrate, the semiconductor layer having a first exposure surface and a second exposure surface; A first electrode on the first exposure surface of the semiconductor layer; A second electrode on the second exposed surface of the semiconductor layer; And a second phosphor layer positioned on the first exposure surface and / or the second exposure surface except for the first electrode and / or the second electrode.

The present invention can provide a light emitting device capable of color conversion including a phosphor layer in a chip manufacturing step rather than a packaging process, and thus can easily produce a light emitting device package that emits light of various colors, The color can be effectively converted to emit light of high purity, and the conversion of such a color can be varied. In addition, the phosphor layer and the electrode are formed in a pattern is to improve the light extraction effect.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the invention allows for various modifications and variations, specific embodiments thereof are illustrated by way of example in the drawings and will be described in detail below. However, it is not intended to be exhaustive or to limit the invention to the precise forms disclosed, but rather the invention includes all modifications, equivalents, and alternatives consistent with the spirit of the invention as defined by the claims.

When an element such as a layer, region or substrate is referred to as being on another component "on", it will be understood that it may be directly on another element or there may be an intermediate element in between. . If a part of a component, such as a surface, is expressed as 'inner', it will be understood that this means that it is farther from the outside of the device than other parts of the element.

Furthermore, relative terms such as "beneath" or "overlies" refer to the relationship of one layer or region to one layer or region and another layer or region with respect to the substrate or reference layer, as shown in the figures. Can be used to describe.

It will be understood that these terms are intended to include other directions of the device in addition to the direction depicted in the figures. Finally, the term 'directly' means that there is no element in between. As used herein, the term 'and / or' includes any and all combinations of one or more of the recorded related items.

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers, and / or regions, such elements, components, regions, layers, and / or regions It will be understood that it should not be limited by these terms.

Embodiments of the present invention will be described with reference to a gallium nitride (GaN) based light emitting device formed on a nonconductive substrate such as, for example, a sapphire (Al ₂ O ₃ ) based substrate. However, the present invention is not limited to this structure.

Embodiments of the invention may use other substrates, including conductive substrates. Thus, combinations of AlGaInP diodes on GaP substrates, GaN diodes on SiC substrates, SiC diodes on SiC substrates, SiC diodes on sapphire substrates, and / or GaN, SiC, AlN, ZnO and / or nitride based diodes on other substrates may be included. have. Moreover, the present invention is not limited to the use of the diode region. Other forms of active area may also be used in accordance with some embodiments of the present invention.

The present invention can provide a light emitting device in a chip unit in which a phosphor layer for changing a wavelength of light emitted from a semiconductor layer is stacked on a semiconductor layer forming a light emitting device. Such a light emitting device may be laminated as a layer of a chip structure during a light emitting device chip fabrication process instead of being filled with a molding in a package process.

The light emitting device and the phosphor layer may be variously combined according to the color of light to be implemented. That is, for white light emission, it is possible to manufacture a combination of a blue light emitting element and a yellow phosphor layer, a UV light emitting element and a red, green, and blue phosphor layer, and a combination of a light emitting element and a phosphor layer that emits various other colors. In addition, it is possible to fabricate a light emitting device chip that emits virtually all colors.

Therefore, a light emitting device package which emits light of various colors can be easily manufactured, and the color emitted in this process can be effectively converted to emit light of high purity, and the conversion of such colors can be varied. .

First Embodiment

As shown in FIG. 1, the reflective layer 40 is positioned on the support layer 50, and the first electrode 20 and the semiconductor layer 10 are positioned on the reflective layer 40. The semiconductor layer 10 may be formed of a p-type semiconductor layer 11, an active layer 12, and an n-type semiconductor layer 13. That is, the n-type semiconductor layer 13 forms a light extraction surface. However, of course, the p-type semiconductor layer 11 may be stacked to form a light extraction surface.

In some cases, the reflective layer 40 and the first electrode 20 (in this case, a p-type electrode) may be formed as one layer as a reflective ohmic electrode.

The support layer 50 is made of a metal or semiconductor and is bonded to the reflective layer 40 by a method such as plating or bonding, wherein a bonding metal layer (not shown) and / or is between the reflective layer 40 and the support layer 50. A diffusion barrier layer (not shown) may be further included.

A second electrode 30 (in this case, an n-type electrode) is positioned on the n-type semiconductor layer 13, and a phosphor is disposed around the second electrode 30 on the n-type semiconductor layer 13, which forms a light extraction surface. Layer 60 is located (see FIG. 2).

As described above, the phosphor layer 60 absorbs light emitted from the active layer 12 of the semiconductor layer 10 to emit light having a changed wavelength, and the light having the changed wavelength is emitted from the active layer 12. The mixed light can be mixed with light of different colors, for example white light.

The phosphor layer 60 may be formed by deposition by a method such as CVD (chemical vapor deposition), PVD (sputtering, e-beam evaporation, etc.), and materials such as YAG, TAG, Silicate series, and SAM series may be used. Can be. In addition, the phosphor layer 60 may be conductive.

At this time, if the thin film is defined as a film having a thickness of 10 μm or less, the above-described phosphor layer 60 is vacuum deposited as the phosphor thin film.

On the other hand, as shown in Figure 3, the phosphor layer 62 may be formed higher than the second electrode 30, and may cover a portion of the second electrode 30.

In addition, as shown in FIG. 4, the phosphor layer 63 may be further positioned between the first electrode 20 and the reflective layer 40. As such, the phosphor layer 62 partially covering the second electrode 30 or the phosphor layer 63 positioned between the first electrode 20 and the reflective layer 40 may improve the wavelength conversion efficiency of light. .

Second Embodiment

As shown in FIG. 5, the reflective layer 40, the first electrode 20, and the n-type semiconductor layer 11, the active layer 12, and the p-type semiconductor layer 13 are sequentially disposed on the support layer 50. The semiconductor layer 10 including the is positioned.

In this case, the second electrode 31 positioned on the p-type semiconductor layer 13 may be divided into a plurality of cells, and the plurality of second electrodes 31 may form a lattice pattern as shown in FIG. 6. Can be. The pattern of the second electrode 31 may form various patterns such as a triangular lattice pattern in addition to the square lattice pattern shown in FIG. 6.

In this case, the phosphor layer 61 may be filled on the surface of the semiconductor layer 10 between the second electrodes 31 forming the pattern. The characteristics of the phosphor layer 61 may be the same as in the first embodiment. As such, the second electrode 31 and the phosphor layer 61 forming the pattern may play a role as a photonic crystal to improve extraction efficiency of light emitted from the semiconductor layer 10.

In some cases, the transparent electrode 70 may be further positioned on the surface on which the second electrode 31 and the phosphor layer 61 are formed.

On the other hand, as shown in Figure 7, the second electrode 32 may form a partition structure connected to each other. That is, the phosphor layer 64 may be partitioned and formed on the semiconductor layer 10 in the state shown in FIG. 8, and the phosphor layer 64 may be formed on the surface of the semiconductor layer 10 between the second electrodes 32 partitioned and formed as described above. Can be filled.

In this case, a part of the second electrode 32 of the barrier rib structure 32 may be formed with a pad portion 32a for forming an electrode pad for wire bonding. This is because, as shown in FIG. 8, when the second electrode 32 has a partition structure, an area for forming the pad of the second electrode 32 may be small.

As described above, the second electrodes 31 and 32 forming the pattern or barrier rib structure may effectively spread current in the semiconductor layer 10.

Parts other than those described above may be the same as in the first embodiment.

Third Embodiment

As shown in FIG. 9, the reflective layer 400, the first electrode 200, and the p-type semiconductor layer 110, the active layer 120, and the n-type semiconductor layer 130 are formed on the support layer 500. In the structure in which the semiconductor layer 100 is sequentially positioned, the phosphor layer 600 may be formed on a portion including the side surface of the semiconductor layer 100 as well as the light emitting surface on the n-type semiconductor layer 130.

That is, as shown, the phosphor layer 600 may be formed to cover the outer side of the second electrode 300 and the side surface of the semiconductor layer 100 on the light emitting surface, the phosphor layer 600 is a first It may be formed to reach the side of the electrode 200 and the reflective layer 400.

In this case, the phosphor layer 600 may be formed at a position higher than that of the second electrode 300, and may be formed to cover a portion of the second electrode 300.

Meanwhile, as shown in FIG. 10, the phosphor layer 610 may be formed to cover a larger area of the semiconductor layer 100.

That is, the contact portion divided by the groove 411 is positioned on the reflective layer 410, and the first electrode 210 may be in contact with the contact portion. In this case, the first electrode 210 has a structure covering a part of the groove 411, and as shown in FIG. 10, a space is formed at the side of the reflective layer 410. The phosphor layer 610 may be formed up to the side surface of the reflective layer 410 formed as described above.

In this case, the insulating layer 700 may be positioned on an exposed surface of the semiconductor layer 100, that is, a portion of the semiconductor layer 100 that is partially exposed to the side and top surfaces of the semiconductor layer 100. The phosphor layer 610 is formed on the insulating layer 700 formed as described above.

As illustrated, the insulating layer 700 may cover a portion of the side surface and the upper surface of the second electrode 300.

Other parts that are not described may be the same as the first embodiment or the second embodiment.

Fourth Embodiment

As shown in FIG. 11, the above-described configuration including the phosphor layer on the semiconductor layer can also be applied to the horizontal light emitting device structure.

That is, the semiconductor layer 10 including the n-type semiconductor layer 13, the active layer 12, and the p-type semiconductor layer 11 is positioned on the substrate 80, and on the p-type semiconductor layer 11. The first electrode 21 is positioned, and the phosphor layer 65 is positioned at the periphery of the first electrode 21.

In addition, the second electrode 33 is positioned at a portion where the n-type semiconductor layer 13 is opened. In this case, the phosphor layer may be located outside the second electrode 33 (not shown).

In this case, the reflective layer 41 may be positioned below the substrate 80, and the reflective layer 41 may allow the light emitted from the active layer 12 to be reflected and travel upward. Therefore, the phosphor layer 67 may be further positioned between the substrate 80 and the reflective layer 41 so that a wavelength change of light may occur in this process.

In addition, as shown in FIG. 12, the phosphor layer 68 may be formed to have a structure covering all exposed surfaces of the semiconductor layer 10. As illustrated, the semiconductor layer 10 and the substrate 80 may have a structure surrounded by both the phosphor layer 68.

That is, the phosphor layer 68 is positioned on the outer side of the first electrode 21 and the outer side of the second electrode 33, and on the side surfaces of the semiconductor layer 10 and the substrate 80. It can cause wavelength conversion of the emitted light.

On the other hand, as shown in Figure 13, in the structure as shown in Figure 12, the insulating layer 90 may be located between the phosphor layer 69 and the semiconductor layer 10. In addition, the insulating layer 90 may be positioned between the phosphor layer 69 and the substrate 80.

The insulating layer 90 may serve to prevent leakage current when driving the device and protect the semiconductor layer 10 during the manufacturing process.

Parts other than those described above may be the same as the first to third embodiments.

The above embodiment is an example for explaining the technical idea of the present invention in detail, and the present invention is not limited to the above embodiment, various modifications are possible, and various embodiments of the technical idea are all protected by the present invention. It belongs to the scope.

1 to 4 are diagrams showing a first embodiment of the present invention.

5 to 8 are diagrams showing a second embodiment of the present invention.

9 and 10 are diagrams showing a third embodiment of the present invention.

11 to 13 are diagrams showing a fourth embodiment of the present invention.

Claims (13)

In the nitride-based light emitting device, A reflective layer; A first electrode on the reflective layer; A semiconductor layer on the first electrode; A second electrode on the semiconductor layer; And a phosphor layer positioned on a portion of the semiconductor layer other than the second electrode to convert wavelengths of light emitted from the semiconductor layer. The nitride-based light emitting device according to claim 1, wherein the reflective layer is located on a support layer made of a metal or a semiconductor. The nitride-based light emitting device according to claim 1, wherein the phosphor layer covers a part of the second electrode. The nitride-based light emitting device according to claim 1, wherein the phosphor layer is further formed on at least one side surface of the semiconductor layer, the first electrode, and the reflective layer. The nitride-based light emitting device according to claim 4, wherein an insulating layer is positioned between the phosphor layer and at least one of the semiconductor layer, the first electrode, and the reflective layer. The nitride-based light emitting device of claim 1, further comprising a phosphor layer between the first electrode and the reflective layer. The nitride-based light emitting device according to claim 4, wherein a contact portion divided by a groove is positioned at a center side of the reflective layer, and the first electrode is in contact with the contact portion. The nitride-based light emitting device of claim 7, wherein the phosphor layer is connected to a groove of the reflective layer. In the nitride-based light emitting device, A reflective layer; A first phosphor layer positioned on the reflective layer; A substrate positioned on the first phosphor layer; A semiconductor layer on the substrate, the semiconductor layer having a first exposure surface and a second exposure surface; A first electrode on the first exposure surface of the semiconductor layer; A second electrode on the second exposed surface of the semiconductor layer; And a second phosphor layer positioned on the first exposure surface and / or the second exposure surface except for the first electrode and / or the second electrode. The nitride-based light emitting device according to claim 9, wherein the second phosphor layer is further formed on side surfaces of the semiconductor layer and / or the substrate. The nitride-based light emitting device according to claim 9, wherein an insulating layer is positioned between the second phosphor layer and the side surfaces of the semiconductor layer and / or the substrate. The nitride-based light emitting device according to claim 1 or 9, wherein the second electrode forms a plurality of lattice patterns. The nitride-based light emitting device according to claim 1 or 9, wherein the second electrode has a partition structure connected to each other.

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