KR100998018B1 - Semiconductor light emitting device having diffractive optical element pattern - Google Patents

Abstract

A semiconductor light emitting device is disclosed. The semiconductor light emitting device includes a substrate, a first conductive semiconductor layer formed on the substrate, an active layer formed on the first conductive semiconductor layer, a second conductive semiconductor layer formed on the active layer, and a second conductive semiconductor layer. And a DOE pattern formed of a transparent material to be formed and provided to the diffractive optical element (DOE).

Light emitting element, DOE pattern, diffraction

Description

Semiconductor light emitting device having a DOE pattern {Semiconductor light emitting device having diffractive optical element pattern}

The present invention relates to a semiconductor light emitting device having a DOE pattern of the present invention, and more particularly, to a semiconductor light emitting device including a DOE pattern on a configuration including a light emitting surface.

Recently, LEDs (light emitting devices) are much more energy-saving than conventional light sources, and can be used almost semi-permanently. Due to these advantages, LED is not only used as the main light source of mobile IT devices such as mobile phones, but also its applications such as light sources of large displays and flashes of cameras are rapidly spreading.

These LEDs require different optical performances depending on the field of use. For example, LEDs used in camera flashes must have high light efficiency within the area required. However, the LED which is a surface light source outputs light at a relatively wide angle (for example, 120 degrees or more), and it was required to adjust the area (angle) to which light is irradiated.

To this end, a method of adjusting the irradiation area of the light output from the LED has been developed by attaching a lens on the LED. However, even when using a separate lens configuration, it is difficult to implement a LED having a uniform and high light efficiency in a certain area, there is a problem due to the process and cost increase by using a separate lens configuration.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a semiconductor light emitting device which diffracts light emitted to the outside by providing a DOE pattern on a configuration including a light emitting surface.

A semiconductor light emitting device according to an embodiment of the present invention for achieving the above object, a substrate, a first conductive semiconductor layer formed on the substrate, an active layer formed on the first conductive semiconductor layer, the active layer And a DOE pattern formed on the second conductive semiconductor layer, and a DOE pattern formed of a transparent material to be provided as a diffractvie optical element (DOE). In this case, the transparent material constituting the DOE pattern may be part of the second conductivity type semiconductor layer.

The semiconductor light emitting device may further include a transparent electrode layer, and the DOE pattern may be formed of the transparent electrode layer. In this case, the transparent electrode layer may be made of any one material of ITO, ZnO 2 and ZnO.

In the present invention, the DOE pattern may be formed of a plurality of concentric circular patterns. In this case, the plurality of concentric circular patterns may have a spacing of 400 nm to 10 μm, and the plurality of concentric circular patterns may have a smaller interval from the center to the outside.

The semiconductor light emitting device may further include a first electrode layer formed under the substrate and a second electrode layer formed on the second conductive semiconductor layer, and the DOE pattern may be formed of a second electrode layer.

The active layer and the second conductive semiconductor layer may have a mesa structure to expose a portion of the first conductive semiconductor layer. In this case, the display device may further include a first electrode formed on the exposed first conductive semiconductor layer and a second electrode formed in a region where the DOE pattern is not formed among the second conductive semiconductor layer.

The display device may further include a first electrode layer formed on a lower surface of the substrate and a second electrode formed in a region where the DOE pattern is not formed among the second conductive semiconductor layers.

According to the present invention, a DOE pattern of a transparent material provided as a diffractvie optical element (DOE) is formed on a structure including a light emitting surface in a semiconductor light emitting device. Accordingly, by diffracting the light emitted to the outside through the DOE pattern, the semiconductor light emitting device can output uniform and high light to a predetermined region.

In addition, by directly forming a DOE pattern on the configuration including the light emitting surface in the semiconductor light emitting device, there is no need to adopt a separate configuration such as a lens for diffraction, simplifying the configuration of the semiconductor light emitting device, process and cost It can also be reduced.

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

1A and 1B are diagrams illustrating a semiconductor light emitting device according to an embodiment of the present invention. FIG. 1B is a cross-sectional view of the semiconductor light emitting device shown in FIG. 1A taken along the line A-A ', and FIGS. 1A and 1B show substantially the same semiconductor light emitting device.

Referring to FIG. 1B, the semiconductor light emitting device 100 is a vertical light emitting device, and includes a substrate 110, a first conductivity type semiconductor layer 120, an active layer 130, and a second conductivity type semiconductor layer 140. And a first electrode layer 150 formed on the bottom surface of the substrate 110 and a second electrode 160 formed on the second conductive semiconductor layer 140.

The semiconductor light emitting device 100 has a structure in which a first conductive semiconductor layer 120, an active layer 130, and a second conductive semiconductor layer 140 are sequentially stacked on the substrate 110. Such a structure is characterized in that the first conductive semiconductor layer 120, the active layer 130, and the second conductive semiconductor layer 140 are grown on a growth substrate (not shown), such as a sapphire substrate or a SiC substrate. It may be formed through a process of moving bonding on the substrate 110. In this case, when the first conductive semiconductor layer 120, the active layer 130, and the second conductive semiconductor layer 140 are bonded to the substrate 110, the growth substrate is removed using a laser lift-off or the like. The first electrode layer 150 is formed on the bottom surface of the substrate 110, and the second electrode 160 is formed on the second conductive semiconductor layer 140.

In the semiconductor light emitting device 100 illustrated in FIG. 1B, the first conductivity-type semiconductor layer 120 may be a p-type semiconductor layer, and the second conductivity-type semiconductor layer 130 may be an n-type semiconductor layer. In addition, the first electrode layer 150 may be a p-type electrode, and the second electrode layer 160 may be an n-type electrode.

Meanwhile, the semiconductor light emitting device 100 includes a DOE (Diffractvie Optical Element) 141 formed on the second conductive semiconductor layer 140. In this case, the DOE pattern 141 may be part of the second conductive semiconductor layer 140 configuration, as shown in FIGS. 1A and 1B. The DOE pattern 141 may be formed by wet or dry etching the upper surface of the second conductive semiconductor layer 140 to correspond to the required pattern.

In addition, the DOE pattern 141 is made of a transparent material, and when light generated from the active layer 130 is output to the outside, the DOE pattern 141 is provided to a diffractive optical element (DOE) for diffraction of light.

As shown in FIG. 1A, the DOE pattern 141 may be formed of a plurality of concentric circular patterns, and each of the plurality of concentric circular patterns may have a spacing within a range of 400 nm to 10 μm with a neighboring pattern. Do.

On the other hand, when the light generated in the active layer 130 passes through the DOE pattern 141 through the second conductivity-type semiconductor layer 140, the light is output through a plurality of concentric circular pattern, a plurality of concentric circular Light is also output through the gaps between the patterns. In particular, the gaps between the plurality of concentric patterns are used as a plurality of slits, and light generated in the active layer 130 is diffracted while passing through the plurality of slits. As the light is diffracted as described above, the light is irradiated to a predetermined area without spreading widely, so that a uniform and high light efficiency can be obtained in a required area. In this case, the predetermined area may vary depending on the product to which the light emitting device is applied. For example, when the light emitting device is used in the camera flash, the predetermined area may be 90 ° or less based on the light emitting device.

In addition, the second conductive semiconductor layer 140 is etched to form a DOE pattern 141 on an upper surface thereof, so that a separate structure such as a lens is not required to implement a diffraction function, thereby providing a semiconductor light emitting device 100. ), And the process and cost can be reduced.

2 to 4 are diagrams illustrating a semiconductor light emitting device according to another exemplary embodiment of the present invention. The semiconductor light emitting devices shown in FIGS. 2 to 4 have a difference according to the configuration in which the DOE pattern is formed, and the function of the DOE pattern is the same as that shown in FIGS. 1A and 1B.

First, the semiconductor light emitting device 200 illustrated in FIG. 2 is a light emitting device having a horizontal structure, and includes a substrate 210, a first conductive semiconductor layer 220, an active layer 230, and a second conductive semiconductor layer 240. And a transparent electrode layer 250. The first electrode 260 formed on the first conductive semiconductor layer 220 exposed by the mesa structure and the second electrode 270 formed on a portion of the transparent electrode layer 250 are included.

The semiconductor light emitting device 200 illustrated in FIG. 2 includes a first conductive semiconductor layer 220, an active layer 230, and a second conductive semiconductor layer 240 on a substrate 210 formed of a sapphire substrate or a SiC substrate. It is prepared by laminating.

Meanwhile, the transparent electrode layer 250 is formed on the second conductivity type semiconductor layer 240, and includes a DOE (Diffractvie Optical Element) 241 pattern. In this case, the DOE pattern 241 is directly formed on the second conductive semiconductor layer 240, and the transparent electrode layer 250 is deposited on the second conductive semiconductor layer 240 on which the DOE pattern 241 is formed. The transparent electrode layer 250 also has a structure having a DOE pattern.

DOE pattern 241 has a plurality of concentric circular patterns, and the plurality of concentric circular patterns have a spacing of 400 nm to 10 μm, as shown in FIG. 1A. When passing through the DOE pattern 241, the diffraction phenomenon of light occurs as the wavelength of the light is longer and the interval between the patterns is smaller. Therefore, in consideration of the wavelength of the light generated in the active layer 230, it is possible to adjust the interval between the plurality of concentric patterns within the range of 400nm to 10㎛.

In addition, as shown in FIG. 2, a plurality of concentric circular patterns have smaller intervals from the center to the outside. This is because gaps between a plurality of concentric patterns are used as a plurality of slits, and the smaller the length of the slits is, the more the diffraction occurs. That is, in the center of the semiconductor light emitting device 200, the interval is widened to output the balanced light, and the interval is relatively narrowed so that the light is diffracted relatively well. Accordingly, the light diffraction increases toward the outside, so that the light is concentrated close to the center area, thereby providing light uniformly and highly efficient in a certain area.

Meanwhile, the semiconductor light emitting device 300 illustrated in FIG. 3 is a light emitting device having a horizontal structure, and includes a substrate 310, a first conductive semiconductor layer 320, an active layer 330, and a second conductive semiconductor layer 340. And a transparent electrode layer 350. And a first electrode 360 formed on the first conductive semiconductor layer 320 exposed by the mesa structure and a second electrode 370 formed on a portion of the second conductive semiconductor layer 340. do.

FIG. 3 has the same structure as that of FIG. 2, but the configuration in which the DOE pattern 351 is formed is different. Specifically, in the semiconductor light emitting device 300 illustrated in FIG. 3, the DOE pattern 351 may be formed on the transparent electrode layer 350 instead of the second conductive semiconductor layer 340. That is, after the transparent electrode layer 350 is formed on the second conductive semiconductor layer 340, the DOE pattern 351 may be formed by etching the transparent electrode layer 350. In this case, as the etching method of the transparent electrode layer 350, wet etching, laser irradiation, imprinting using a holographic pattern or a master pattern may be used. As such, by diffracting the light using the DOE pattern 351 formed on the transparent electrode layer 350, it is possible to provide light uniformly and highly efficient in a predetermined area.

The semiconductor light emitting device 400 illustrated in FIG. 4 is a vertical light emitting device, and includes a substrate 410, a first conductive semiconductor layer 420, an active layer 430, and a second conductive semiconductor layer 440. And a first electrode layer 450 formed on the bottom surface of the substrate 410 and a second electrode layer 460 formed on the second conductive semiconductor layer 440.

Meanwhile, in the semiconductor light emitting device 400 illustrated in FIG. 4, a DOE pattern 461 is formed on the second electrode layer 460. Specifically, after forming a mask pattern using a photoresist on the second conductivity-type semiconductor layer 420, by depositing a metal material, as shown in FIG. 4, the second electrode layer having the DOE pattern 461 formed thereon ( 460 may be formed.

In FIG. 4, the second electrode layer 460 may be formed of an opaque material instead of a transparent material. In this case, light may be extracted through an interval between the DOE patterns 461 formed on the second electrode layer 460, and light is diffracted in the course of passing the interval.

As such, by diffracting the light using the DOE pattern 461 formed on the second electrode layer 460, it is possible to provide light uniformly and highly efficient in a predetermined area.

While the above has been shown and described with respect to preferred embodiments of the present invention, the present invention is not limited to the above-described appropriate embodiments, it is usually in the art without departing from the gist of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1A and 1B illustrate a semiconductor light emitting device according to an embodiment of the present invention, and

2 to 4 illustrate a semiconductor light emitting device according to various embodiments of the present disclosure.

Explanation of symbols on the main parts of the drawings

100, 200, 300, 400: semiconductor light emitting device

110, 210, 310, 410: substrate

120, 220, 320, 420: first conductive semiconductor layer

130, 230, 330, 430: active layer

140, 240, 340, 440: second conductive semiconductor layer

141, 241, 351, 461: DOE pattern

Claims (11)

Board; A first conductivity type semiconductor layer formed on the substrate; An active layer formed on the first conductivity type semiconductor layer; A second conductivity type semiconductor layer formed on the active layer; And A DOE pattern formed on the second conductive semiconductor layer and formed of a transparent material to be provided as a diffractive optical element (DOE), The DOE pattern is a semiconductor light emitting device, characterized in that consisting of a transparent electrode layer. delete delete The method of claim 1, The transparent electrode layer is a semiconductor light emitting device, characterized in that made of any one material of ITO, ZnO 2 and ZnO. The method of claim 1, The DOE pattern is a semiconductor light emitting device, characterized in that consisting of a plurality of concentric pattern. Board; A first conductivity type semiconductor layer formed on the substrate; An active layer formed on the first conductivity type semiconductor layer; A second conductivity type semiconductor layer formed on the active layer; And A DOE pattern formed on the second conductive semiconductor layer and formed of a transparent material to be provided as a diffractive optical element (DOE), wherein the DOE pattern is formed of a plurality of concentric circular patterns, The plurality of concentric pattern is a semiconductor light emitting device, characterized in that having a spacing of 400nm to 10㎛. The method of claim 5, The plurality of concentric circular pattern is a semiconductor light emitting device, characterized in that the interval becomes smaller from the center to the outside. Board; A first conductivity type semiconductor layer formed on the substrate; An active layer formed on the first conductivity type semiconductor layer; A second conductivity type semiconductor layer formed on the active layer; A DOE pattern formed on the second conductive semiconductor layer and made of a transparent material to provide a diffractive optical element (DOE); A first electrode layer formed under the substrate; And And a second electrode layer formed on the second conductive semiconductor layer, wherein the DOE pattern comprises a second electrode layer. The method according to any one of claims 1 to 6, The active layer and the second conductive semiconductor layer has a mesa structure so that a portion of the first conductive semiconductor layer is exposed. 10. The method of claim 9, A first electrode formed on the exposed first conductive semiconductor layer; And, And a second electrode formed in a region in which the DOE pattern is not formed in the second conductive semiconductor layer. The method according to any one of claims 1 to 6, A first electrode layer formed on the bottom surface of the substrate; And, And a second electrode formed in a region in which the DOE pattern is not formed in the second conductive semiconductor layer.

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