CN204243083U - Light emitting device - Google Patents

Abstract

The utility model discloses a kind of luminescent device, and its light with more than 140 degree points to angle.Disclosed a kind of luminescent device comprises: substrate; Semiconductor layer, is formed in the one side of substrate; Semi light transmitting part, is formed on the another side of substrate.The utility model adopts semi light transmitting part, thus the thickness of substrate is maintained thinner, and is reflected by the light launched to the upper side of substrate, thus has the advantage that the light that can realize more than 140 degree points to angle.

Description

Light emitting device

technical field

The utility model relates to a light-emitting device, in particular to a light-emitting device with a light directing angle of more than 140 degrees.

Background technique

Generally, a gallium nitride-based light-emitting device is produced by growing a gallium nitride-based semiconductor layer on a sapphire substrate.

Recently, a flip-chip type light emitting device in which the light emitting device is directly mounted on a circuit board is used for thinning.

In a general flip-chip type light emitting device, a GaN-based semiconductor layer including an electrode pattern is grown on one side of a sapphire substrate, and light emitted from the GaN-based semiconductor layer is emitted from the other side of the sapphire substrate. Here, the general flip-chip type light emitting device can expand the beam angle of light by adjusting the thickness of the sapphire substrate.

However, it is difficult for ordinary flip-chip light-emitting devices to achieve a light directing angle of more than 140 degrees even if the thickness of the sapphire substrate is designed to be more than 400 μm, and as the thickness of the sapphire substrate increases, the light efficiency caused by light loss The lower the more prominent.

Utility model content

The technical problem to be solved by the utility model is to provide a light emitting device that can increase the light directing angle of the light emitting device.

Another technical problem to be solved by the utility model is to provide a sapphire substrate designed to be thinner and form a semi-transparent layer on the sapphire substrate to minimize light loss, thereby improving light efficiency and achieving a 140-degree Light-emitting devices with light pointing angles.

A light emitting device according to an embodiment of the present invention includes: a substrate; a semiconductor layer formed on one side of the substrate; and a semi-transparent portion formed on the other side of the substrate.

Preferably, the semi-transparent portion includes multiple layers, and the multiple layers have different refractive indices from each other.

Preferably, the multi-layers are composed of SiN, SiO ₂ , TiO ₂ , and HfO ₂ material layers that are different from each other.

Preferably, the multiple layers are composed of a first layer to a third layer, and the first layer is a material layer selected from SiN, SiO ₂ , TiO ₂ , and HfO ₂ .

Preferably, the multiple layers are composed of the first layer to the third layer, and the second layer is a material layer selected from SiN, SiO ₂ , TiO ₂ , and HfO ₂ .

Preferably, the multiple layers are composed of a first layer to a third layer, and the third layer is a material layer selected from SiN, SiO ₂ , TiO ₂ , and HfO ₂ .

Preferably, the multi-layer is composed of first to third layers arranged in sequence, the first layer has a lower refractive index than the second layer on the first layer, and is located on the second The third layer on the layer has a lower refractive index than the second layer.

Preferably, the multiple layers are composed of the first layer to the third layer arranged in sequence, and the refractive index becomes smaller as the first layer approaches the third layer.

Preferably, the multiple layers are composed of the first layer to the third layer arranged in sequence, and the refractive index increases from the first layer to the third layer.

Preferably, the semi-transparent portion has a different refractive index than the substrate.

Preferably, the semi-transparent part is made of a thin-film metal layer.

Preferably, the thickness of the substrate is less than 250 μm.

Preferably, the light emitting device is a flip chip type light emitting device.

According to an embodiment of the present utility model, in the light-emitting device of the present utility model, one side of the substrate is provided with a semiconductor lamination portion and the other surface of the substrate is provided with a semi-transparent portion whose refractive index is different from that of the substrate, so that the emitted By reflecting part of the light on the other surface of the substrate, the light directivity angle can be enlarged.

In the present invention, the light directing angle of more than 140 degrees is realized, and the thickness of the substrate is designed to be less than 250 μm, so that the light loss can be minimized, and it has the advantage of reducing the thickness of the light emitting device.

Moreover, in the present invention, the chip of the light-emitting device is directly flip-chip bonded or surface-mounted on the circuit board, so compared with the light-emitting device in the form of a common package, it has the advantages of high efficiency and miniaturization.

Description of drawings

FIG. 1 is a cross-sectional view schematically illustrating a light emitting device according to an embodiment of the present invention.

2a is a plan view specifically showing the structure of the light emitting device in FIG. 1, and FIG. 2b is a cross-sectional view showing the light emitting device taken along line I-I' in FIG. 2a.

FIG. 3 is a diagram showing an area A in FIG. 1 according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating an area A in FIG. 1 according to another embodiment of the present invention.

FIG. 5 is a diagram illustrating an area A in FIG. 1 according to still another embodiment of the present invention.

Symbol Description:

100: light emitting diode 200, 300, 400: translucent part

Detailed ways

Hereinafter, embodiments of the present utility model will be described in detail with reference to the accompanying drawings. The embodiments described below are provided as examples in order to fully convey the idea of the present invention to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In addition, the width, length, thickness, and the like of constituent elements in the drawings may be exaggerated for convenience. Throughout the specification, the same reference numerals denote the same constituent elements.

Fig. 1 schematically illustrates a sectional view of a light-emitting device according to an embodiment of the present invention, Fig. 2a is a plan view specifically illustrating the structure of the light-emitting device in Fig. A cross-sectional view of a light emitting device taken along line I', FIG. 3 is a diagram showing the area A of FIG. 1 according to an embodiment of the present invention.

As shown in FIGS. 1 to 3 , a light emitting device according to an embodiment of the present invention includes: a light emitting structure 110 including a substrate 111 and a semiconductor laminate 113 ; and a semi-transparent portion 200 .

The semiconductor lamination part 113 of the light emitting structure 110 is provided on one side of the substrate 111 , and the semi-transparent part 200 is provided on the other side of the substrate 111 .

The light emitting diode 100 is a flip-chip type, and the electrode pads 37a, 37b are located at the bottom of the chip.

The substrate 111 may be a growth substrate for growing a semiconductor layer, such as a sapphire substrate or a gallium nitride substrate. For example, the substrate 111 is a heterogeneous substrate suitable for growing gallium nitride-based semiconductor layers, and has a first refractive index. For example, the substrate 111 may be a sapphire substrate having a refractive index of about 1.78 at a wavelength of 450 nm or a SiC substrate having a refractive index of about 2.72.

In the embodiment of the present invention, the substrate 111 is limited to a sapphire substrate for description. The substrate 111 has a thickness of 250 μm or less.

The semi-transparent portion 200 has a refractive index different from that of the substrate 111 . For example, the semi-transparent part 200 may have a refractive index smaller than 1.78. The semi-transparent part 200 has a refractive index smaller than that of the substrate 111 , so that the light direction angle of the light emitting device can be enlarged by the light totally reflected at the interface between the semi-transparent part 200 and the substrate 111 . Here, although it is limited to the case where the semi-transparent portion 200 has a refractive index smaller than that of the substrate 111 , it is not limited thereto and may have a higher refractive index than the substrate 111 .

The light emitting structure 110 is located on one side of the semi-transparent portion 200 . The light emitting structure 110 includes a first conductive type semiconductor layer 23 and a plurality of mesa M located on the substrate 111 , and the plurality of mesa M include an active layer 25 and a second conductive type semiconductor layer 27 respectively. The active layer 25 is located between the first conductive type semiconductor layer 23 and the second conductive type semiconductor layer 27 . In addition, reflective electrodes 30 are provided on the plurality of bosses M respectively.

As shown in the figure, the plurality of bosses M may have an elongated shape extending parallel to each other in one side direction. Such a shape simplifies the work of forming a plurality of mesas M of the same shape in a plurality of chip regions on the growth substrate 111 .

In addition, the reflective electrode 30 may be formed on each of the mesas M after forming a plurality of mesas M, but it is not limited thereto, and the second conductive type semiconductor layer 27 may also be grown and formed on the first mesa M before forming the mesas M. on the second conductivity type semiconductor layer 27 . The reflective electrode 30 covers most of the upper surface of the boss M, and has substantially the same shape as the planar shape of the boss M. As shown in FIG.

The reflective electrode 30 includes a reflective layer 28 and may further include a barrier layer 29 . The barrier layer 29 may cover the upper surface and side surfaces of the reflective layer 28 . For example, the reflective layer 28 may be patterned and the barrier layer 29 may be formed thereon so that the barrier layer 29 may cover the upper surface and side surfaces of the reflective layer 28 . For example, the reflective layer 28 can be formed by vapor-depositing or patterning Ag, Ag alloy, Ni/Ag, NiZn/Ag, TiO/Ag layers. In addition, the barrier layer 29 may be formed of Ni, Cr, Ti, Pt, Rd, Ru, W, Mo, TiW or a composite layer thereof, so as to prevent diffusion or contamination of metal substances in the reflective layer.

After the plurality of mesas M are formed, edges of the first conductive type semiconductor layer 23 may also be etched. Accordingly, the upper surface of the substrate 111 can be exposed. The side surfaces of the first conductivity type semiconductor layer 23 may also be formed to be inclined.

The light emitting device chip of the present invention further includes a lower insulating layer 31 covering the plurality of bosses M and the first conductive type semiconductor layer 23 . The lower insulating layer 31 has openings for allowing electrical connection to the first conductive type semiconductor layer 23 and the second conductive type semiconductor layer 27 in specific regions. For example, the lower insulating layer 31 may have an opening portion exposing the first conductive type semiconductor layer 23 and an opening portion exposing the reflective electrode 30 .

The opening portion may be located in an area between the bosses M and near the edge of the substrate 111 , and may have an elongated shape extending along the bosses M. Referring to FIG. In addition, the opening is limited to the upper portion of the boss M, and is provided so as to be offset to the same end side of the boss.

The light emitting device of the present invention includes a current spreading layer 33 formed on the lower insulating layer 31 . The current spreading layer 33 covers the plurality of mesas M and the first conductive type semiconductor layer 23 . Also, the current spreading layer 33 has openings located within the upper regions of the respective mesas M and exposing the reflective electrodes. The current spreading layer 33 can be in ohmic contact with the first conductive type semiconductor layer 23 through the opening of the lower insulating layer 31 . The current spreading layer 33 is insulated from the plurality of mesas M and the reflective electrode 30 by the lower insulating layer 31 .

The openings of the current spreading layer 33 each have a wider area than the openings of the lower insulating layer 31 to prevent the current spreading layer 33 from being connected to the reflective electrode 30 .

The current spreading layer 33 is formed on almost the entire area of the substrate 111 except the opening. Therefore, electric current can be easily dispersed through the current spreading layer 33 . The current spreading layer 33 may include a highly reflective metal layer such as an Al layer, and the highly reflective metal layer may be formed on an adhesive layer such as Ti, Cr, or Ni. In addition, a single-layer or composite-layer protective layer of materials such as Ni, Cr, and Au can be formed on the highly reflective metal layer. The current spreading layer 33 may have, for example, a multilayer structure of Ti/Al/Ti/Ni/Au.

The light emitting device of the present invention is formed with an upper insulating layer 35 on the current spreading layer 33 . Upper insulating layer 35 has an opening exposing current spreading layer 33 , and has an opening exposing reflective electrode 30 .

The upper insulating layer 35 can be formed by using an oxide insulating layer, a nitride insulating layer, mixed layers or intersecting layers of these insulating layers, polymers such as polyimide, polytetrafluoroethylene, and parylene.

A first pad 37 a and a second pad 37 b are formed on the upper insulating layer 35 . The first pad 37 a is connected to the current spreading layer 33 through the opening of the upper insulating layer 35 , and the second pad 37 b is connected to the reflective electrode 30 through the opening of the upper insulating layer 35 . In order to mount the light emitting device on a circuit board or the like, the first pad 37a and the second pad 37b may be used for connecting bumps or as pads for surface mounting (SMT: Surface Mount Technology).

The first pad 37a and the second pad 37b may be formed together through the same process, for example, a photolithography and etching technique or a lift-off technique may be used. The first pad 37 a and the second pad 37 b may include, for example, an adhesive layer of materials such as Ti, Cr, and Ni, and a high-conductivity metal layer of materials such as Al, Cu, Ag, and Au. The first pad 37a and the second pad 37b may be formed such that the end portions are on the same plane, and thus the light emitting device chip may be flip-chip bonded on the conductive pattern formed on the circuit substrate at the same height.

Then, the substrate 111 is divided into units of individual light emitting devices, so that the light emitting devices are manufactured. The growth substrate 111 may be removed from the light emitting device chips before or after being divided in units of individual light emitting devices.

According to the present embodiment, the light emitting device is provided with a semiconductor lamination part 113 on one side of the substrate 111, and is provided with a semi-transparent part having a refractive index different from that of the substrate 111 on the other side of the substrate 111. 200, so that a part of the light emitted to the other surface of the substrate 111 is reflected and a part is transmitted, thereby expanding the light directing angle.

Moreover, in the present invention, the thickness of the substrate 111 is designed to be less than 250 μm, so that the light loss can be minimized, and it is beneficial to the thinning of the light emitting device.

Moreover, in the present invention, the light-emitting diode 100 is directly flip-chip bonded or surface-mounted on the circuit board, so it has the advantages of achieving high efficiency and miniaturization compared with a common light-emitting device in the form of a package.

FIG. 4 is a diagram illustrating an area A in FIG. 1 according to another embodiment of the present invention.

As shown in FIG. 4 , in a light-emitting device according to another embodiment of the present invention, the structure of the semi-transparent portion 300 on the substrate 111 is different from the one embodiment described, and all other structures are the same as those according to the present invention. The light emitting device of the one embodiment described above is the same, and thus detailed description of the configuration other than the configuration of the semi-transparent portion 300 is omitted.

The semi-transparent portion 300 has a refractive index different from that of the substrate 111 . The semi-transparent part 300 is composed of more than two layers. For example, the semi-transparent part 300 includes a first layer 301 , a second layer 303 and a third layer 305 . The first layer 301 to the third layer 305 are formed of SiN, SiO ₂ , TiO ₂ , HfO _{2 ,} etc., and are composed of different materials.

The first layer 301 to the third layer 305 have different refractive indices from each other. For example, the refractive index of the first layer 301 is smaller than that of the second layer 303 on the first layer 301 , and the refractive index of the third layer 305 on the second layer 303 is The refractive index is smaller than the refractive index of the second layer 303. Also, although the refractive indices of the first layer 301 and the third layer 305 are not particularly limited, for example, the refractive index of the first layer 301 may be smaller than that of the third layer 305 . For example, the first layer 301 may be SiO ₂ , the second layer 303 may be TiO ₂ , and the third layer 305 may be HfO ₂ .

In addition, the first layer 301 to the third layer 305 may have smaller and smaller refractive indices as they get away from the substrate 111 . For example, the first layer 301 may be TiO ₂ , the second layer 303 may be HfO ₂ , and the third layer 305 may be SiO ₂ .

In addition, the first layer 301 to the third layer 305 may also have larger and larger refractive indices as they get away from the substrate 111 .

The light-emitting device according to another embodiment of the present invention reflects a part of the light incident from the semiconductor lamination part through the substrate 111 and transmits the other part through the semi-transparent part 300 composed of two or more layers, Thereby, the light directing angle can be enlarged.

Moreover, in the present invention, the thickness of the substrate 111 is designed to be less than 250 μm, so that the light loss can be minimized, and it is beneficial to the thinning of the light emitting device.

Moreover, in the present invention, the chip of the light-emitting device is directly flip-chip bonded or surface-mounted on the circuit board, so compared with the light-emitting device in the form of a common package, it has the advantages of high efficiency and miniaturization.

FIG. 5 is a diagram illustrating an area A in FIG. 1 according to still another embodiment of the present invention.

As shown in FIG. 5 , in a light emitting device according to yet another embodiment of the present utility model, the structure of the semi-transparent portion 400 located on the substrate 111 is different from the one embodiment described, and all other structures are the same as those according to The light emitting device of the one embodiment described above is the same, and thus detailed description of the configuration other than the configuration of the semi-transparent portion 400 is omitted.

The semi-transparent portion 400 has a refractive index different from that of the substrate 111 . The semi-transparent part 400 transmits part of the light and reflects the other part. The semi-transparent portion 400 may be made of metal material. The light transmittance of the semi-transparent part 400 can be adjusted by adjusting the thickness. The semi-transparent part 400 is composed of a thin film metal layer.

In the light-emitting device according to still another embodiment of the present invention, part of the light incident from the semiconductor laminated part through the substrate 111 is reflected and the other part is transmitted by the semi-transparent part 400 composed of a thin-film metal layer. , so that the light pointing angle can be enlarged.

Moreover, in the present invention, the thickness of the substrate 111 is designed to be less than 250 μm, so that the light loss can be minimized, and it is beneficial to the thinning of the light emitting device.

Moreover, in the present invention, the chip of the light-emitting device is directly flip-chip bonded or surface-mounted on the circuit board, so compared with the light-emitting device in the form of a common package, it has the advantages of high efficiency and miniaturization.

A variety of embodiments and features of the present utility model have been described above, but the utility model is not limited to the above-described embodiments and features, and can be performed in various ways without departing from the scope of the idea of the present utility model. deformation.

Claims (13)

1. a luminescent device, is characterized in that, comprising:

Substrate;

Semiconductor layer, is formed in the one side of described substrate;

Semi light transmitting part, is formed on the another side of described substrate.

2. luminescent device as claimed in claim 1, it is characterized in that, described semi light transmitting part comprises multilayer, and described multilayer has mutually different refractive index.

3. luminescent device as claimed in claim 2, it is characterized in that, described multilayer is by SiN, SiO ₂, TiO ₂, HfO ₂in mutually different material layer form.

4. luminescent device as claimed in claim 3, it is characterized in that, described multilayer is made up of to third layer ground floor, and described ground floor is SiN, SiO ₂, TiO ₂, HfO ₂in a kind of material layer.

5. luminescent device as claimed in claim 3, it is characterized in that, described multilayer is made up of to third layer ground floor, and the described second layer is SiN, SiO ₂, TiO ₂, HfO ₂in a kind of material layer.

6. luminescent device as claimed in claim 3, it is characterized in that, described multilayer is made up of to third layer ground floor, and described third layer is SiN, SiO ₂, TiO ₂, HfO ₂in a kind of material layer.

7. luminescent device as claimed in claim 2, it is characterized in that, described multilayer is made up of to third layer the ground floor set gradually, described ground floor has the refractive index less than the second layer be positioned on described ground floor, and the described third layer be positioned on the described second layer has the refractive index less than the described second layer.

8. luminescent device as claimed in claim 2, it is characterized in that, described multilayer is made up of to third layer the ground floor set gradually, and tends to described third layer along with from described ground floor, and refractive index is more and more less.

9. luminescent device as claimed in claim 2, it is characterized in that, described multilayer is made up of to third layer the ground floor set gradually, and tends to described third layer along with from described ground floor, and refractive index is increasing.

10. luminescent device as claimed in claim 1, it is characterized in that, described semi light transmitting part has the refractive index being different from described substrate.

11. luminescent devices as claimed in claim 1, it is characterized in that, described semi light transmitting part is made up of thin film metal layer.

12. luminescent devices as claimed in claim 1, is characterized in that, the thickness of described substrate is less than 250 μm.

13. luminescent devices as claimed in claim 1, it is characterized in that, described luminescent device is the luminescent device of flip-chip variety.