TW201444115A - Light emitting device and manufacturing method thereof - Google Patents

Abstract

The invention discloses a light emitting device and manufacturing method thereof. The light emitting device includes an epitaxial substrate, an epitaxial structure, a first reflection layer, a protection layer, a barrier layer and a second reflection layer. The epitaxial structure has a first semiconductor layer, an active layer and a second semiconductor layer disposed on the epitaxial substrate sequentially. The epitaxial structure includes at least a groove. The groove exposes the part of the first semiconductor layer. The first reflection layer is disposed on the second semiconductor layer. The protection layer is disposed on the first reflection layer. The barrier layer is disposed on the protection layer and covered the protection layer. The active layer, the second semiconductor layer, the first reflection layer, the protection layer and the barrier layer define a mesa area. The second reflection layer is disposed on the epitaxial substrate and at least extends to the periphery of the epitaxial substrate from the periphery of the mesa area.

Description

Light emitting device and method of manufacturing same

The present invention relates to a light-emitting device and a method of fabricating the same, and more particularly to a light-emitting device having a flip-chip structure and a method of fabricating the same.

The light-emitting diode is a light-emitting element made of a semiconductor material, and has the advantages of low power consumption, long component life, fast reaction speed, and the like, and the small size is easy to be made into a very small or array type component. As technology continues to advance, its range of applications has expanded from indicator lights and backlights to lighting.

1A, FIG. 1B and FIG. 1C, FIG. 1A is a schematic top view of a conventional light-emitting device 1, and FIGS. 1B and 1C are schematic cross-sectional views of a line A-A and a line B-B of FIG. 1A, respectively. Here, the light-emitting device 1 is a flip-chip structure light-emitting diode light-emitting device, and is exemplified by downward light-emitting.

The light-emitting device 1 includes an epitaxial substrate 11 , an epitaxial structure 12 , a reflective layer 13 , a protective layer 14 , a barrier layer 15 , and an insulating layer 16 . In addition, the illuminating device 1 further includes a first electrode P1, a second electrode P2, an isolation trench T and a plurality of recesses U.

The epitaxial structure 12 is disposed on the epitaxial substrate 11 , and the reflective layer 13 is disposed on the epitaxial structure 12 . The epitaxial structure 12 has an n-GaN layer 121, a multiple quantum well layer 122, and a p-GaN layer 123 sequentially disposed on the epitaxial substrate 11, and the reflective layer 13 is usually a high reflectivity metal. The material reflects the light emitted by the light-emitting device 1 to further improve the light-emitting efficiency of the light-emitting device 1. The protective layer 14 is disposed on the reflective layer 13, and the barrier layer 15 is disposed on the protective layer 14 and covers the protective layer 14 and the reflective layer 13. Wherein, the protective layer 14 can protect the reflective layer 13 from the subsequent process damage to the reflective layer 13 and cause a decrease in reflectivity. In addition, the barrier layer 15 can also protect the reflective layer 13 from the expansion of the reflective layer 13 due to subsequent processes or component operations. Problems such as scattered or degraded.

The insulating layer 16 is disposed on the barrier layer 15 and the epitaxial structure 12, and the first electrode P1 and the second electrode P2 are respectively located on opposite sides of the isolation trench T, and the first electrode P1 can be transmitted through the isolation trench T. The second electrode P2 is electrically isolated. The first electrode P1 is electrically connected to the n-GaN layer 121 through one of the first via holes H1 of the insulating layer 16 located in the recess U, and the second electrode P2 is transmitted through the insulating layer 16. The via hole H2 is electrically connected to the p-GaN layer 123 via the barrier layer 15 , the protective layer 14 , and the reflective layer 13 . By supplying power to the first electrode P1 and the second electrode P2 and reflecting by the light of the reflective layer 13, the light-emitting device 1 can emit downward light. The current flowing through the n-GaN layer 121 is dispersed by electrically connecting the first electrode P1 and the n-GaN layer 121 by the first via holes H1 located in the recesses U.

However, in the structure of the conventional light-emitting device 1, although the light-emitting device 1 has the reflective layer 13 to reflect the light emitted by the light-emitting device 1, the reflective layer 13 does not completely cover the entire light-emitting area of the light-emitting device 1, so that the emitted light is emitted. The light is not reflected all the way down. Therefore, as shown in the left side of FIG. 1B and the right side of FIG. 1C, a part of the light is emitted upward in the area around the outer periphery of the light-emitting device 1, which indirectly causes the light extraction efficiency of the light-emitting device 1. The reduction.

Therefore, how to provide a light-emitting device and a method of manufacturing the same, which can improve the light extraction efficiency of the light-emitting device, is an object that the industry has been striving for.

In view of the above problems, an object of the present invention is to provide a light-emitting device and a method of manufacturing the same, which can improve the light extraction efficiency of the light-emitting device.

To achieve the above objective, the present invention provides a light emitting device including an epitaxial substrate, an epitaxial structure, a first reflective layer, a protective layer, a barrier layer, and a second reflective layer. The epitaxial structure has a first semiconductor layer, an active layer and a second semiconductor layer sequentially disposed on the epitaxial substrate. The epitaxial structure comprises at least one recess, and the recess exposes a portion of the first semiconductor layer. The first reflective layer is disposed on the second semiconductor layer. The protective layer is disposed on the first reflective layer. The barrier layer is disposed on the protective layer and covers the protective layer. The active layer, the second semiconductor layer, the first reflective layer, the protective layer and the barrier layer define a platform region. The second reflective layer is disposed on the epitaxial substrate, and in the direction of the vertical epitaxial substrate, the second reflective layer extends at least from the periphery of the land region to the epitaxial substrate Periphery.

In order to achieve the above object, the present invention provides a method for fabricating a light emitting device, comprising: forming an epitaxial structure on an epitaxial substrate, wherein the epitaxial structure has a first semiconductor layer, an active layer, and a second semiconductor layer. Arranging on the epitaxial substrate; removing a portion of the second semiconductor layer and the active layer and exposing the first semiconductor layer to form at least one recess; forming a first reflective layer on the second semiconductor layer; forming a protective layer on Forming a barrier layer on the protective layer, wherein the barrier layer covers the protective layer and the first reflective layer, and the active layer, the second semiconductor layer, the first reflective layer, the protective layer, and the barrier layer Defining a platform region; and forming a second reflective layer over the epitaxial substrate, wherein the second reflective layer extends at least from a periphery of the land region to a periphery of the epitaxial substrate in a direction perpendicular to the epitaxial substrate.

In one embodiment, the light emitting device further includes an insulating layer disposed on the barrier layer and the first semiconductor layer, the insulating layer covering at least the barrier layer and a portion of the surface of the first semiconductor layer.

In an embodiment, the light emitting device further includes a first electrode and a second electrode respectively disposed on the insulating layer, the first electrode extends from the land region to the periphery of the epitaxial substrate, and the second electrode extends from the land region to The periphery of the epitaxial substrate.

In one embodiment, the insulating layer has a first through hole and a second through hole, the first through hole is located in the groove, and the first through hole exposes a portion of the first semiconductor layer, and the first electrode is A via is electrically connected to the first semiconductor layer, a second via is located on the second semiconductor layer, and a portion of the barrier layer is exposed, and the second electrode is electrically connected to the second semiconductor layer through the second via.

In an embodiment, the light emitting device further includes an isolation trench disposed on the insulating layer, and the first electrode and the second electrode are respectively located on opposite sides of the isolation trench.

In one embodiment, the second reflective layer includes a first electrode and a second electrode, and the insulating layer extends from the barrier layer to the periphery of the epitaxial substrate to electrically isolate the first electrode from the first semiconductor layer and electrically The second electrode is isolated from the first semiconductor layer.

In one embodiment, the first electrode is in direct contact with the first semiconductor layer at a periphery of the epitaxial substrate.

In an embodiment, the second reflective layer covers a portion of the insulating layer and is in direct contact with the first semiconductor layer.

In an embodiment, the second reflective layer is formed by a sidewall of the first reflective layer or a barrier layer The sidewall extends to the periphery of the epitaxial substrate and is in direct contact with the first semiconductor layer and is covered by the insulating layer.

In one embodiment, the second reflective layer includes an insulating layer covering at least a portion of the surface of the barrier layer and the first semiconductor layer and in direct contact with the first semiconductor layer.

In an embodiment, the manufacturing method further includes: forming an insulating layer on the barrier layer and the first semiconductor layer, wherein the insulating layer covers at least a portion of the surface of the barrier layer and the first semiconductor layer, and the insulating layer has a first The through hole and the second through hole are located in the groove, the first through hole exposes a portion of the first semiconductor layer, and the second through hole is located on the second semiconductor layer, and a portion of the barrier layer is exposed.

In an embodiment, the manufacturing method further includes: forming a first electrode and a second electrode on the insulating layer, wherein the first electrode and the second electrode are respectively located on opposite sides of an isolation trench, and the first electrode is formed by the platform The second electrode extends from the land area to the periphery of the epitaxial substrate, and the first electrode is electrically connected to the first semiconductor layer through the first via hole, and the second electrode is connected to the second semiconductor layer The hole is electrically connected to the second semiconductor layer.

According to the present invention, a light emitting device and a method of fabricating the same according to the present invention include an epitaxial substrate, an epitaxial structure, a first reflective layer, a protective layer, a barrier layer, and a second reflective layer. The active layer, the second semiconductor layer, the first reflective layer, the protective layer and the barrier layer define a platform region. In addition, in the direction of the vertical epitaxial substrate, the second reflective layer extends at least from the periphery of the land region to the periphery of the epitaxial substrate. Thereby, compared with the conventional one, when the light-emitting device emits light, the light that is incident on the outer peripheral edge of the light-emitting device (ie, outside the land) is reflected back by the second reflective layer, thereby improving the light extraction efficiency of the light-emitting device. .

1, 2, 2a~2d‧‧‧ illuminating devices

11, 21‧‧‧ epitaxial substrate

12, 22‧‧‧ epitaxial structure

121‧‧‧n-GaN layer

122‧‧‧Multiple Quantum Wells

123‧‧‧p-GaN layer

13‧‧‧reflective layer

14, 24‧‧ ‧ protective layer

15, 25‧‧‧ barrier layer

16, 26‧‧‧Insulation

221‧‧‧First semiconductor layer

222‧‧‧ active layer

223‧‧‧Second semiconductor layer

23‧‧‧First reflective layer

27‧‧‧Second reflective layer

A-A, B-B‧‧‧ Straight line

C‧‧‧Cut Road

H1‧‧‧first through hole

H2‧‧‧second through hole

M‧‧‧ Platform Area

S01~S06‧‧‧Steps

P‧‧‧ Peripheral Area

P1‧‧‧first electrode

P2‧‧‧second electrode

T‧‧‧Isolation trench

U‧‧‧ Groove

FIG. 1A is a schematic top view of a conventional light emitting device.

1B and 1C are schematic cross-sectional views of the straight line A-A and the straight line B-B of FIG. 1A, respectively.

2 is a schematic view of the preferred embodiment of the present invention, before the two light-emitting devices are separated.

3A is a top plan view of a light emitting device in accordance with a preferred embodiment of the present invention.

3B and 3C are schematic cross-sectional views of the straight line A-A and the straight line B-B of FIG. 3A, respectively.

3D and FIG. 3E, FIG. 4A and FIG. 4B, FIG. 5A and FIG. 5B, FIG. 6A and FIG. 6B are respectively schematic cross-sectional views along line AA and line BB in FIG. 3A in the light-emitting device of another embodiment. .

FIG. 7 is a flow chart of a method of fabricating a light emitting device according to a preferred embodiment of the present invention.

Hereinafter, a light-emitting device and a method of manufacturing the same according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals. In addition, the illustration of the present invention is merely illustrative and does not represent true dimensions and proportions.

Referring to FIG. 2, FIG. 3A to FIG. 3C, FIG. 2 is a schematic diagram of a light-emitting device 2 according to a preferred embodiment of the present invention. FIG. FIG. 3B and FIG. 3C are schematic cross-sectional views of the line AA and the line BB of FIG. 3A, respectively. Herein, the light-emitting device 2 is exemplified by a flip-chip light-emitting diode that emits light downward. 2 shows two illuminating devices 2 connected before uncut, which is of course not limited thereto. In the actual process, the number and arrangement of the illuminating devices 2 may be other modes. Here, there is a scribe line C between the two illuminating devices 2, and when cutting by the scribe line C, two independent illuminating devices 2 can be separated. In addition, FIG. 2 only shows the land area M, the peripheral area P, the epitaxial substrate 21, and the second reflective layer 27 of the light-emitting device 2.

The light-emitting device 2 includes an epitaxial substrate 21, an epitaxial structure 22, a first reflective layer 23, a protective layer 24, a barrier layer 25, and a second reflective layer 27. In addition, the light emitting device 2 further includes an insulating layer 26. Here, the epitaxial structure 22, the first reflective layer 23, the protective layer 24, the barrier layer 25, the insulating layer 26, and the second reflective layer 27 are respectively disposed on the epitaxial substrate 21.

The epitaxial structure 22 is disposed on the epitaxial substrate 21. among them. The epitaxial substrate 21 may be light transmissive or opaque. In the present embodiment, the epitaxial substrate 21 is exemplified by a light transmissive sapphire substrate (Sapphire). Of course, the epitaxial substrate 21 may also be tantalum carbide, aluminum oxide, gallium nitride, glass, quartz, gallium phosphide or gallium arsenide substrate, etc., when the epitaxial substrate 21 is an opaque substrate, all of them must be completed. After the LED process, the epitaxial substrate 21 is removed to avoid the occurrence of light blocking. In addition, the epitaxial structure 22 is formed by a material gap, and the commonly used group III-V elements are large. It can be divided into four categories: GaP/GaAsP series, AlGaAs series, AlGaInP series, and GaN series. Here, the epitaxial structure 22 has a first semiconductor layer 221, an active layer 222, and a second semiconductor layer 223 as an example. The first semiconductor layer 221 , the active layer 222 , and the second semiconductor layer 223 are sequentially adjacent to the epitaxial substrate 21 and away from the epitaxial substrate 21 . The first semiconductor layer 221 and the second semiconductor layer 223 have different electrical properties. When the first semiconductor layer 221 is P-type, the second electrical semiconductor layer 223 is N-type; and when the first semiconductor 221 layer is N-type, The second semiconductor layer 223 is of a P type. Here, the first semiconductor layer 221 is N-type gallium nitride (GaN), the active layer 222 is a multiple quantum-well (MQW) structure, and the second semiconductor layer 223 is a P-type gallium nitride. For example. The first semiconductor layer 221 of this embodiment is partially exposed for use as a subsequent electrode.

The first reflective layer 23 is disposed on the second semiconductor layer 223 and is in contact with the second semiconductor layer 223. The first reflective layer 23 of this embodiment may be a single layer of high reflectivity metal layer or a plurality of high reflectivity metal layers, and the material thereof may include, for example, silver, aluminum, gold, titanium, chromium, nickel, indium tin oxide. Or a combination thereof, and may be, for example, a single layer of silver, a double layer of nickel/silver, or indium tin oxide/silver to increase the reflectance of light and improve the first reflective layer 23 and the second semiconductor layer 223 Ohmic contact characteristics between.

The protective layer 24 is disposed on the first reflective layer 23. In this embodiment, a protective layer 24 is formed on the upper surface of the first reflective layer 23 to cover the first reflective layer 23. The protective layer 24 may be composed of a single layer or a plurality of metal layers, and the material thereof may include, for example, nickel, titanium, tungsten, or a combination thereof, and may be, for example, a single layer of nickel, titanium, tungsten or titanium tungsten, or Double layer of nickel/titanium, or titanium/nickel. The protective layer 24 can protect the first reflective layer 23 from chemicals or high temperature damage used in subsequent processes to the first reflective layer 23 to cause a decrease in reflectance.

The barrier layer 25 is disposed on the protective layer 24 and at least completely covers the protective layer 24. Here, the barrier layer 25 completely covers the protective layer 24 and the sidewall of the first reflective layer 23 and contacts the second semiconductor layer 223 of the epitaxial structure 22. The barrier layer 25 can also protect the first reflective layer 23 from problems such as diffusion or deterioration of the first reflective layer 23 due to subsequent processes or component operations. The barrier layer 25 can be deposited by evaporation or sputtering and formed on the protective layer 24 and the epitaxial structure 22 by a lift-off process. The barrier layer 25 may be composed of a single layer or a plurality of layers of metal materials, and the material thereof may include, for example, nickel, titanium, tungsten, gold, platinum, or a combination thereof, and may be, for example, Single layer of nickel, titanium, gold, tungsten, platinum or titanium tungsten, or double layer of nickel/titanium, gold/tungsten or titanium tungsten/platinum, or three layers of nickel/titanium/platinum, or four layers of titanium/ Nickel/titanium/platinum, etc.

In the present invention, the active layer 222, the second semiconductor layer 223, the first reflective layer 23, the protective layer 24, and the barrier layer 25 define a mesa region M of the light-emitting device. The platform area M referred to herein is not a completely flat area, in other words, the platform area M may have a structure such as high and low undulations or grooves. In addition, as shown in FIG. 2, the area between the outer side of the land area M and the adjacent light-emitting device 2 may be referred to as a peripheral area P before the cutting process is performed.

The second reflective layer 27 is disposed on the epitaxial substrate 21. As shown in FIG. 2, in the direction of the vertical epitaxial substrate 21 (ie, when the light-emitting device 2 is viewed from above), the second reflective layer 27 extends at least from the periphery of the land region M, and is adjacent to the adjacent portion before the cutting process is performed. The second reflective layer 27 of the illumination device is connected. The so-called "periphery" here does not refer to the precise edge, but the position near the edge can be called the periphery. In other words, in the direction of the vertical epitaxial substrate 21, the second reflective layer 27 extends at least from the periphery of the periphery of the first reflective layer 23 on the land area M toward the outer side of the epitaxial substrate 21 and can extend to the scribe line. Thereby, the center of C (the center) can be reflected toward the peripheral edge of the outer side of the land area M of the light-emitting device 2, whereby the light extraction efficiency of the light-emitting device 2 can be improved. Wherein, the arrangement of the second reflective layer 27 can generate an additional reflective area, which is about 11%~14% higher than that of the first reflective layer 23, so that the light emitting device can be relatively improved. 2 light extraction efficiency. Wherein, the second reflective layer 27 may be a single layer or a multilayer structure, and the material thereof comprises a metal, an alloy or an insulating material. The structure of the second reflective layer 27 and its material properties will be described below.

The insulating layer 26 is disposed on the barrier layer 25 and the first semiconductor layer 221 , wherein the insulating layer 26 covers at least a portion of the surface of the barrier layer 25 and the first semiconductor layer 221 . Here, the insulating layer 26 covers the barrier layer 25 and contacts the first semiconductor layer 221 of the epitaxial structure 22 . In the present embodiment, the insulating layer 26 is made of, for example, a single layer or a plurality of layers of a highly insulating material such as SiO ₂ , SiN _X , Titanium Dioxide (TiO ₂ ) or SOG.

In addition, the illuminating device 2 further includes a first electrode P1 and a second electrode P2. The first electrode P1 and the second electrode P2 are respectively disposed on the insulating layer 26. The first electrode P1 and the second electrode P2 may be composed of a single layer or a plurality of layers of metal materials, and may be made of, for example, gold, tin, aluminum, chromium, platinum, titanium, or a combination thereof, and may be, for example, a single layer. Gold, aluminum or gold tin, Or double layer of titanium/gold or titanium/aluminum, or three layers of chromium/platinum/gold. In addition, in different embodiments, the materials of the first electrode P1 and the second electrode P2 may also be silver, aluminum, rhenium (Rh) or other highly reflective metal materials, respectively. By supplying power to the first electrode P1 and the second electrode P2, the light-emitting device 2 can emit downward light. As shown in FIG. 3A and FIG. 3B, the light-emitting device 2 further includes an isolation trench T, the isolation trench T is located on the insulating layer 26, and the first electrode P1 and the second electrode P2 are respectively located in the isolation trench T. Relative sides. Therefore, as shown in FIG. 3A, the first electrode P1 extends from the isolation trench T of the land region M to the right side, the upper side, and the lower side to the periphery of the epitaxial substrate 21, and the second electrode P2 is separated by the isolation region of the land area M. The groove T extends to the left side, the upper side, and the lower side to the periphery of the epitaxial substrate 21. The insulating layer 26 has a first via hole H1 and a second via hole H2, and the first electrode P1 is electrically connected to the first semiconductor layer 221 through the first via hole H1, and the second electrode P2 is The second via hole H2 , the barrier layer 25 , the protective layer 24 , and the reflective layer 23 are electrically connected to the second semiconductor layer 223 . Here, the number of the first through holes H1 is, for example but not limited to, 25, and the number of the second through holes H2 is, for example but not limited to, four, and the arrangement position thereof is not limited to the position of FIG. 3A.

In addition, the epitaxial structure 22 includes at least one groove U, and the groove U is disposed corresponding to the first through hole H1. In this embodiment, the plurality of grooves U respectively correspond to the plurality of first through holes H1, and for example, but not limited to, forming a two-dimensional array arrangement. In other embodiments, the number of the grooves U and the relative arrangement positions may be different. The first through holes H1 are correspondingly located in the grooves U, and the first electrodes P1 and the insulating layers 26 respectively extend from the inside of the grooves U to the outside of the grooves U. Here, the current flowing through the first semiconductor layer 221 is dispersed by electrically connecting the first electrode P1 and the first semiconductor layer 221 by the first via holes H1 located in the recesses U. After the epitaxial structure 22 is formed, a portion of the second semiconductor layer 223 and the active layer 222 may be removed by etching (wet or dry) or floating process to expose the first semiconductor layer 221 to form the recess U. In addition, the insulating layer 26 is deposited behind the barrier layer 25, and the barrier layer 25 and a portion of the insulating layer 26 on the first semiconductor layer 221 may be etched (wet or dry) or floated to define the first layer. a pattern of the via hole H1 and the second via hole H2, and then defining a pattern region of the first electrode P1 and the second electrode P2, and then depositing by evaporation or sputtering, respectively, and forming a first electrode P1 and a first through the floating process The second electrode P2 is in a region of the insulating layer 26, the barrier layer 25, and the first semiconductor layer 221 in the recess U that is not covered by the insulating layer 26.

In the present embodiment, as shown in FIGS. 3B and 3C, the second reflective layer 27 includes a first electrode P1 and a second electrode P2. In other words, the first electrode P1 and the second electrode P2 of the present embodiment use, for example, but not limited to, silver, aluminum, rhenium (Rh) or other highly reflective metal, in addition to being supplied to the power supply electrode of the light-emitting device 2, The second reflective layer 27 reflects the area of the outer periphery of the land area M of the light-emitting device 2, thereby improving the light extraction efficiency of the light-emitting device 2. In addition, in the peripheral region P, the insulating layer 26 of the present embodiment extends from the barrier layer 25 to the periphery of the epitaxial substrate 21 to electrically isolate the first electrode P1 from the first semiconductor layer 221 (see FIG. 3C). And electrically isolating the second electrode P2 from the first semiconductor layer 221 (as shown in FIG. 3B).

Referring to FIG. 3D and FIG. 3E, respectively, in a light-emitting device 2a of another embodiment, a cross-sectional view along a line A-A and a line B-B as shown in FIG. 3A is shown. 3D is the same as FIG. 3B and will not be described again.

The main difference between FIG. 3E and FIG. 3C is that the first electrode P1 extends from the land region M to the right side, the upper side, and the lower side of the isolation trench T to the periphery of the epitaxial substrate 21, but is adjacent to the periphery of the epitaxial substrate 21. (ie, the peripheral region P), the first electrode P1 is in direct contact with the first semiconductor layer 221 and is electrically connected (ie, the insulating layer 26 does not extend to the periphery of the epitaxial substrate 21), whereby the light-emitting device 2a can be added. In addition to the light extraction efficiency, the ohmic contact area of the first electrode P1 and the first semiconductor layer 221 can also be increased, and therefore, the output of the forward bias of the light-emitting device 2a can be reduced.

In addition, other technical features of the illuminating device 2a can refer to the same components of the illuminating device 2, and details are not described herein again.

Referring to FIG. 4A and FIG. 4B, FIG. 5A and FIG. 5B, FIG. 6A and FIG. 6B, respectively, in the light-emitting devices 2b to 2d of another embodiment, as shown in FIG. 3A along the line AA and the line BB. A schematic cross-sectional view.

As shown in FIG. 4A and FIG. 4B, the main difference from FIG. 3B and FIG. 3C is that the second reflective layer 27 of the light-emitting device 2b of FIGS. 4A and 4B does not include the first electrode P1 and the second electrode P2, but A multilayer coating layer is additionally provided to become the second reflective layer 27 of the light-emitting device 2b. The first electrode P1 and the second electrode P2 are disposed to the edge of the land area M, and do not extend to the periphery of the epitaxial substrate 21, and the second reflective layer 27 extends from the periphery of the land area M to the epitaxial substrate 21, respectively. The insulating layer 26 is covered on the periphery and is in direct contact with the first semiconductor layer 221. The material of the second reflective layer 27 of the embodiment may be a single layer or a plurality of layers of high insulation. Here, the second reflective layer 27 is a multi-layer coating layer (such as a Bragg mirror), and is repeatedly staggered and stacked by two materials of different refractive indexes to form a mirror, and the material thereof includes, for example, cerium oxide/titanium oxide ( SiO ₂ /TiO ₂ ) or cerium oxide/cerium nitride (SiO ₂ /SiN _X ). It is also mentioned that another layer of highly reflective metal layer (for example, silver, aluminum, germanium) can be formed on the second reflective layer 27, thereby further improving the light extraction efficiency.

In addition, other technical features of the illuminating device 2b can refer to the same components of the illuminating device 2, and details are not described herein again.

As shown in FIG. 5A and FIG. 5B, the main difference from FIG. 4A and FIG. 4B is that the second reflective layer 27 of the light-emitting device 2c of the present embodiment is formed before the insulating layer 26, and the second reflective layer 27 is composed of The sidewall of the first reflective layer 23 or the sidewall of the barrier layer 25 extends to the periphery of the epitaxial substrate 21 and is in direct contact with the first semiconductor layer 221 and is covered by the insulating layer 26. Also, since the second reflective layer 27 is formed before the insulating layer 26, the first via hole H1 penetrates through the second reflective layer 27 in addition to the insulating layer 26 in the land area M, and the first electrode P1 is still transmitted. The first via hole H1 is electrically connected to the first semiconductor layer 221 . In addition, in this embodiment, the second reflective layer 27 is formed before the barrier layer 25, and since the barrier layer 25 mainly functions to protect the first mirror layer 23, generally, a metal that is not highly reflective is selected. When the second reflective layer 27 is adjacent to the sidewall of the first reflective layer 23, a better reflection effect can be obtained. In this embodiment, the barrier layer 25 is partially covered on the second reflective layer 27. However, in another embodiment, the second reflective layer 27 is formed behind the barrier layer 25, and therefore, the barrier layer 25 is formed first to completely cover the first reflective layer 23, and the first reflective layer 23 is prevented from being subsequently Problems such as diffusion or deterioration generated during the process or component operation, and then the second reflective layer 27 is formed and adjacent to the sidewall of the barrier layer 25.

In addition, other technical features of the illuminating device 2c can refer to the same components of the illuminating device 2b, and details are not described herein again.

Further, as shown in FIGS. 6A and 6B, the main difference from FIG. 3B and FIG. 3C is that the second reflective layer 27 of the light-emitting device 2d of the present embodiment includes the insulating layer 26. In other words, the insulating layer 26 of the present embodiment is the second reflective layer 27 and is a multi-layer coating layer (such as a Bragg mirror), and is repeatedly stacked and formed by two materials of different refractive indexes to form a mirror, and the material thereof includes, for example, Cerium oxide/cerium oxide (SiO2/TiO2) or cerium oxide/cerium nitride (SiO2/SiNX). The insulating layer 26 is not only an insulating layer of the light-emitting device 2d but also a second reflective layer 27 by its material property to reflect a region that is incident on the outer peripheral edge of the land region M of the light-emitting device 2, thereby improving the light-emitting device. 2 light extraction efficiency. The insulating layer 26 (the second reflective layer 27) extends from above the barrier layer 25 to the periphery of the epitaxial substrate 21. In addition, the second electrode P2 of the present embodiment is formed in the land area M and does not extend to the periphery of the epitaxial substrate 21.

In addition, other technical features of the illuminating device 2d can refer to the same components of the illuminating device 2, and details are not described herein again.

Please refer to FIG. 3A to FIG. 3C and FIG. 7. FIG. 7 is a flow chart showing a manufacturing method of a light-emitting device 2 according to a preferred embodiment of the present invention.

The manufacturing method of the light-emitting device 2 of the present invention may include steps S01 to S06.

As shown in FIG. 3B and FIG. 3C, in step S01, an epitaxial structure 22 is formed on an epitaxial substrate 21, wherein the epitaxial structure 22 has a first semiconductor layer 221, an active layer 222, and a second semiconductor. The layers 223 are sequentially disposed on the epitaxial substrate 21. The main epitaxial methods for forming the epitaxial structure 22 include Liquid Phase Epitaxy (LPE), Vapor Phase Epitaxy (VPE), and Metal-organic Chemical Vapor. Deposition, MOCVD) is not limited.

Next, in step S02, a portion of the second semiconductor layer 223 and the active layer 222 are removed and the first semiconductor layer 221 is exposed to form at least one recess U. Wherein, the first semiconductor layer 221 of the partial epitaxial structure 22 can be exposed by an etching process to serve as a subsequent electrode. Here, a plurality of grooves U are formed on the epitaxial structure 22, and are arranged in a two-dimensional array as an example. The number and arrangement position of the grooves U are not particularly limited. In addition, in other embodiments, in order to determine that a portion of the first semiconductor layer 221 may be exposed, the first semiconductor layer 221 of the etching process removal portion may also be controlled to ensure that the first semiconductor layer 221 may be exposed.

Next, in step S03, a first reflective layer 23 is formed on the second semiconductor layer 223. Wherein, the first reflective layer 23 can be disposed on the epitaxial structure 22 via an electron gun (E-Gun) evaporation or sputtering process, and alloying is performed at a temperature of 325 to 550 ° C. In the step, the contact resistance between the epitaxial structure 22 and the first reflective layer 23 is reduced by heat through the alloying step, and the reflectance of the first reflective layer 23 to the light is improved.

Next, in step S04, a protective layer 24 is formed on the first reflective layer 23. Here, the protective layer 24 is formed on the first reflective layer 23 to cover the upper surface of the first reflective layer 23. The protective layer 24 can be used in the same deposition process as the first reflective layer 23 to sequentially deposit the first reflective layer 23 and the protective layer 24 on the epitaxial structure 22, and then pass through the lithography and etching (wet or dry). The method of floating or the like completes the pattern definition of the first reflective layer 23 and the protective layer 24 at the same time.

Next, in step S05, a barrier layer 25 is formed on the protective layer 24, wherein the barrier layer 25 at least completely covers the protective layer 24 and the first reflective layer 23, and the active layer 222, the second semiconductor layer 223, the first The reflective layer 23, the protective layer 24 and the barrier layer 25 define a land area M. Here, the barrier layer 25 is a metal layer and completely covers the sidewalls of the protective layer 24 and the first reflective layer 23.

Then, step S06 is performed to form a second reflective layer 27 on the epitaxial substrate 21, wherein the second reflective layer 27 extends at least from the periphery of the land region M to the epitaxial layer in the direction of the vertical epitaxial substrate 21. The periphery of the substrate 21. In the present embodiment, the pattern formation definition of the second reflective layer 27 can be completed by evaporation or sputtering plus a floating process.

However, before the second reflective layer 27 is formed, the method for manufacturing the light-emitting device 2 further includes: forming an insulating layer 26 on the barrier layer 25 and the first semiconductor layer 221, wherein the insulating layer 26 covers at least the barrier layer. 25 and a portion of the surface of the first semiconductor layer 221, and the insulating layer 26 has a first through hole H1 and a second through hole H2, and the first through hole H1 is located in the groove U. Here, the insulating layer 26 may be deposited by evaporation or sputtering, or deposited on the barrier layer 25 and the epitaxial structure 22 by optical coating. The insulating layer 26 may be formed before or after the second reflective layer 27. In the present embodiment, the insulating layer 26 is formed first, and the second reflective layer 27 is formed as an example. In addition, the insulating layer 26 is filled in the recess U, and the first reflective layer 23, the protective layer 24 and the barrier layer 25 are not formed in the recess U, and the first through hole H1 is also located in the corresponding recess. Inside the slot U.

In the embodiment, in the step S06 of forming the second reflective layer 27, the second reflective layer 27 includes a first electrode P1 and a second electrode P2. In other words, the first electrode P1 and the second electrode P2 of the present embodiment are the second reflective layer 27. The first electrode P1 is electrically connected to the first semiconductor layer 221 through the first via hole H1 of the insulating layer 26, and the second electrode P2 is electrically connected to the second semiconductor layer 223 through the second via hole H2 of the insulating layer 26. Sexual connection. In addition, the first electrode P1 and the second electrode P2 are respectively located on opposite sides of an isolation trench T. The first electrode P1 extends from the land area M to the periphery of the epitaxial substrate 21, and the second electrode P2 extends from the land area M to the epitaxial substrate 21. Periphery. In addition, the insulating layer 26 extends from the barrier layer 25 to the periphery of the epitaxial substrate 21 to electrically isolate the second electrode P2 from the first semiconductor layer 221. Herein, the material of the second reflective layer 27 (ie, the first electrode P1 and the second electrode P2) comprises silver, aluminum, rhenium (Rh) or other highly reflective conductive metal to make the first electrode P1 and the second electrode P2 becomes a power supply electrode and becomes a second reflective layer 27 of high reflectance.

In addition, referring to FIG. 4A and FIG. 4B, in the light-emitting device 2b of this aspect, in the step of forming the second reflective layer 27, the second reflective layer 27 is formed behind the insulating layer 26, and covers the portion. The insulating layer 26 is in direct contact with the first semiconductor layer 221 in the peripheral region P. In other words, the second reflective layer 27 is formed after the insulating layer 26 is formed.

In addition, the manufacturing method of the light-emitting device 2b further includes: forming a first electrode P1 and a second electrode P2 on the insulating layer 26, wherein the first electrode P1 and the second electrode P2 are respectively located in an isolation trench T On the opposite sides, the first electrode P1 is formed only in the land area M, and does not extend to the periphery of the epitaxial substrate 21. In addition, the first electrode P1 is electrically connected to the first semiconductor layer 221 through the first via hole H1, and the second electrode P2 is electrically connected to the second semiconductor layer 223 via the second via hole H2. In this embodiment, as shown in FIGS. 4A and 4B, the second reflective layer 27 may be directly adjacent to the first electrode P1 and the second electrode P2 without being overlaid thereon. In another embodiment, the second reflective layer 27 may partially cover the first electrode P1 and the second electrode P2.

In addition, referring to FIG. 5A and FIG. 5B, in the light-emitting device 2c of this aspect, the second reflective layer 27 is formed before the insulating layer 26, and in the step S06 of forming the second reflective layer 27, The second reflective layer 27 extends from the sidewall of the first reflective layer 23 or the sidewall of the barrier layer 25 to the periphery of the epitaxial substrate 21 and is in direct contact with the first semiconductor layer 221 and is covered by the insulating layer 26. In addition, since the second reflective layer 27 is adjacent to the sidewall of the first reflective layer 23 or the sidewall of the barrier layer 25, the second reflective layer 27 is also formed in the land region M, and the second reflective layer 27 is also the first The semiconductor layer 221 is in contact and covered by the insulating layer 26.

In addition, referring to FIG. 6A and FIG. 6B, in the light-emitting device 2d of this aspect, the second reflective layer 27 includes the insulating layer 26. In other words, the insulating layer 26 is the second reflective layer, and the second reflective layer 27 (the insulating layer 26) covers at least the barrier layer 25 and the first semiconductor layer 221 Part of the surface is in direct contact with the first semiconductor layer 221. In other words, the second reflective layer 27 and the insulating layer 26 have the same layer structure. Wherein, the second reflective layer 27 (insulating layer 26) is a multi-layer coating layer (such as a Bragg mirror), and is repeatedly stacked and formed by two materials of different refractive indexes to form a mirror, and the material thereof includes, for example, ceria/titanium. Antimony (SiO2/TiO2) or cerium oxide/cerium nitride (SiO2/SiNX).

In addition, other technical features of the manufacturing method of the light-emitting device of the present invention, including the materials of the respective components, the processes thereof, and the like can be referred to the description of the same components, and will not be described herein.

In summary, a light emitting device and a method of fabricating the same according to the present invention include an epitaxial substrate, an epitaxial structure, a first reflective layer, a protective layer, a barrier layer, and a second reflective layer. The active layer, the second semiconductor layer, the first reflective layer, the protective layer and the barrier layer define a platform region. In addition, in the direction of the vertical epitaxial substrate, the second reflective layer extends at least from the periphery of the land region to the periphery of the epitaxial substrate. Thereby, compared with the conventional one, when the light-emitting device emits light, the light that is incident on the outer peripheral edge of the light-emitting device (ie, outside the land) is reflected back by the second reflective layer, thereby improving the light extraction efficiency of the light-emitting device. .

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

2‧‧‧Lighting device

21‧‧‧ epitaxial substrate

22‧‧‧ epitaxial structure

221‧‧‧First semiconductor layer

222‧‧‧ active layer

223‧‧‧Second semiconductor layer

23‧‧‧First reflective layer

24‧‧‧Protective layer

25‧‧‧Barrier layer

26‧‧‧Insulation

27‧‧‧Second reflective layer

H1‧‧‧first through hole

H2‧‧‧second through hole

M‧‧‧ Platform Area

P‧‧‧ Peripheral Area

P1‧‧‧first electrode

P2‧‧‧second electrode

T‧‧‧Isolation trench

U‧‧‧ Groove

Claims (19)

An illuminating device includes: an epitaxial substrate; an epitaxial structure having a first semiconductor layer, an active layer, and a second semiconductor layer sequentially disposed on the epitaxial substrate, the epitaxial structure comprising at least one recess a groove, the groove exposing a portion of the first semiconductor layer; a first reflective layer disposed on the second semiconductor layer; a protective layer disposed on the first reflective layer; a barrier layer disposed on And protecting the protective layer, the active layer, the second semiconductor layer, the first reflective layer, the protective layer and the barrier layer define a land area; and a second reflective layer disposed on the Above the epitaxial substrate, in a direction perpendicular to the epitaxial substrate, the second reflective layer extends at least from a periphery of the land region to a periphery of the epitaxial substrate. The illuminating device of claim 1, further comprising: an insulating layer disposed on the barrier layer and the first semiconductor layer, the insulating layer covering at least the barrier layer and the first semiconductor layer Part of the surface. The illuminating device of claim 2, further comprising: a first electrode and a second electrode respectively disposed on the insulating layer, the first electrode extending from the platform region to a periphery of the epitaxial substrate The second electrode extends from the land region to a periphery of the epitaxial substrate. The illuminating device of claim 3, wherein the insulating layer has a first through hole and a second through hole, the first through hole is located in the groove, and the first through hole is exposed a portion of the first semiconductor layer, the first electrode is electrically connected to the first semiconductor layer through the first via hole, the second via hole is located on the second semiconductor layer, and the portion of the barrier layer is exposed The second electrode is electrically connected to the second semiconductor layer through the second via. The illuminating device of claim 4, further comprising: an isolation trench located on the insulating layer, wherein the first electrode and the second electrode are respectively located at the spacer Off the opposite sides of the groove. The illuminating device of claim 5, wherein the second reflective layer comprises the first electrode and the second electrode, the insulating layer extending from the barrier layer to a periphery of the epitaxial substrate, Electrically isolating the first electrode from the first semiconductor layer and electrically isolating the second electrode from the first semiconductor layer. The illuminating device of claim 5, wherein the second reflective layer comprises the first electrode and the second electrode, and the first electrode is in direct contact with the first semiconductor layer at a periphery of the epitaxial substrate . The illuminating device of claim 5, wherein the second reflective layer covers a portion of the insulating layer and is in direct contact with the first semiconductor layer. The illuminating device of claim 5, wherein the second reflective layer extends from a sidewall of the first reflective layer or a sidewall of the barrier layer to a periphery of the epitaxial substrate, and the first semiconductor layer Direct contact and covered by the insulating layer. The illuminating device of claim 5, wherein the second reflective layer comprises the insulating layer, the insulating layer covering at least a portion of the surface of the barrier layer and the first semiconductor layer, and the first semiconductor layer direct contact. A method for fabricating a light-emitting device includes: forming an epitaxial structure on an epitaxial substrate, wherein the epitaxial structure has a first semiconductor layer, an active layer, and a second semiconductor layer sequentially disposed on the epitaxial substrate Removing a portion of the second semiconductor layer and the active layer and exposing the first semiconductor layer to form at least one recess; forming a first reflective layer on the second semiconductor layer; forming a protective layer on the first a reflective layer is formed on the protective layer, wherein the barrier layer covers the protective layer and the first reflective layer, and the active layer, the second semiconductor layer, the first reflective layer, the The protective layer and the barrier layer define a land region; and a second reflective layer is formed on the epitaxial substrate, wherein the second reflective layer is at least by the platform region in a direction perpendicular to the epitaxial substrate The periphery extends to the periphery of the epitaxial substrate. The manufacturing method of claim 11, further comprising: forming an insulating layer on the barrier layer and the first semiconductor layer, wherein the insulating layer covers at least the barrier layer and the first semiconductor layer a portion of the surface, the insulating layer has a first through hole and a second through hole, the first through hole is located in the groove, the first through hole exposes a portion of the first semiconductor layer, and the second through hole A hole is located on the second semiconductor and a portion of the barrier layer is exposed. The manufacturing method of claim 12, further comprising: forming a first electrode and a second electrode on the insulating layer, wherein the first electrode and the second electrode are respectively located in an isolation trench On both sides, the first electrode extends from the land area to the periphery of the epitaxial substrate, the second electrode extends from the land area to the periphery of the epitaxial substrate, and the first electrode passes through the first through hole The first semiconductor layer is electrically connected, and the second electrode is electrically connected to the second semiconductor layer through the second via. The manufacturing method of claim 12, wherein the second reflective layer comprises a first electrode and a second electrode, the first electrode and the second electrode are respectively located on opposite sides of an isolation trench, The first electrode extends from the land area to a periphery of the epitaxial substrate, the second electrode extends from the land area to a periphery of the epitaxial substrate, and the first electrode passes the first through hole and the first The semiconductor layer is electrically connected, and the second electrode is electrically connected to the second semiconductor layer through the second via. The manufacturing method of claim 14, wherein the insulating layer extends from the barrier layer to a periphery of the epitaxial substrate to electrically isolate the first electrode from the first semiconductor layer and electrically The second electrode is isolated from the first semiconductor layer. The manufacturing method according to claim 14, wherein the first electrode is in direct contact with the first semiconductor layer on a periphery of the epitaxial substrate. The manufacturing method of claim 12, wherein the second reflective layer is formed after the insulating layer and covers a portion of the insulating layer and is in direct contact with the first semiconductor layer. The manufacturing method of claim 12, wherein the second reflective layer extends from a sidewall of the first reflective layer or a sidewall of the barrier layer to a periphery of the epitaxial substrate, and the first semiconductor The layers are in direct contact and are covered by the insulating layer. The manufacturing method of claim 12, wherein the second reflective layer comprises the insulating layer, the insulating layer covering at least a portion of the surface of the barrier layer and the first semiconductor layer, and the first semiconductor layer direct contact.