TWI610464B - Light emitting diode structure - Google Patents

Abstract

A light emitting diode structure includes a first type doped semiconductor layer, a second type doped semiconductor layer, a light emitting layer, a first electrode, and a second electrode. The light emitting layer is disposed between the first type doped semiconductor layer and the second type doped semiconductor layer. The first electrode is disposed on the first type doped semiconductor layer and includes a plurality of branches. The second electrode is disposed on the second type doped semiconductor layer, the second electrode ring encloses at least one closed region, and the closed region is located between the adjacent two branch portions.

Description

Light-emitting diode structure

The present invention relates to a photovoltaic element structure, and more particularly to a light emitting diode structure.

Light-emitting diode (LED) structures have been widely used in the field of illumination and display because of their low power consumption, environmental protection, long service life and fast response rate. In order to increase the brightness of the light-emitting diode, large-sized crystal grains have been gradually developed. However, the conventional electrode design of the light-emitting diode structure has the disadvantage of causing poor current dispersion, making this electrode design unsuitable for large-sized crystal grains.

In order to improve the above problem of poor current dispersion, another conventional electrode has been developed. Such a conventional electrode includes a first interdigitated electrode disposed on the N-type doped semiconductor layer and a second interdigitated electrode disposed on the P-type doped semiconductor layer. Each of the first interdigitated electrode and the second interdigitated electrode has a plurality of first branch portions and a plurality of second branch portions, wherein only one second branch portion is disposed in the middle of the adjacent two first branch portions. Although this electrode design can improve the problem of poor current dispersion, in this electrode design, due to the mobility of electrons and holes, electricity The mobility of the sub-member is faster than the mobility of the hole, so when the electrons emitted from the first branch portion are transmitted to the second branch portion (or when the hole emitted from the second branch portion is transmitted to the first branch portion), the second sub-point The electron concentration and the hole concentration beside the branch (or beside the first branch) are extremely different, and the electron and hole recombination probability is low, thereby causing the light-emitting diode structure with such a conventional electrode to emit light. Inefficient.

The present invention provides a light emitting diode structure having high luminous efficiency.

An embodiment of the present invention provides a light emitting diode structure including an N-type semiconductor layer, a first electrode, a P-type semiconductor layer, a second electrode, and a light-emitting layer. The first electrode is disposed on the N-type semiconductor layer, and the first electrode includes a plurality of first branch portions. The second electrode is disposed on the P-type semiconductor layer, and the second electrode includes a plurality of second branch portions and an extension portion surrounding the enclosed region. The light emitting layer is disposed between the N-type semiconductor layer and the P-type semiconductor layer. The second branch portion and the extension portion extend respectively between the two adjacent first branch portions.

An embodiment of the present invention provides a light emitting diode structure including an N-type semiconductor layer, a first electrode, a P-type semiconductor layer, a second electrode, and a light-emitting layer. The first electrode includes a plurality of first branch portions. The second electrode is disposed on the P-type semiconductor layer, and the second electrode includes a plurality of second branch portions and an extension portion. The light emitting layer is disposed between the N-type semiconductor layer and the P-type semiconductor layer, and the region where the N-type semiconductor layer is exposed by the light emitting layer and the P-type semiconductor layer is adapted to configure the first electrode. The first branch portions of the first electrode and the second branch portions and the extension portions of the second electrode extend in opposite directions and are opposite to each other Interleaved, and the extension encircles a closed region on the N-type semiconductor layer.

An embodiment of the present invention provides a light emitting diode structure including an N-type semiconductor layer, a first electrode, a P-type semiconductor layer, a second electrode, and a light-emitting layer. The first electrode is disposed on the N-type semiconductor layer, and the first electrode includes a plurality of first branch portions. The second electrode is disposed on the P-type semiconductor layer, and the second electrode includes a plurality of second branch portions and an extension portion. The extension has two extension arms and the ends of the extension arms are connected to enclose a closed area. The light emitting layer is disposed between the N-type semiconductor layer and the P-type semiconductor layer, wherein a distance between the extending arms of the extending portion and the first branch portions is farther than a distance between the extending arms.

Based on the above, the light-emitting diode structure of the embodiment of the present invention can make the electrons in the light-emitting diode structure be arranged by arranging a second electrode enclosing the closed region between adjacent two branch portions of the first electrode. The concentration of the holes is relatively matched, which can effectively promote the recombination of electrons and holes, thereby improving the luminous efficiency of the structure of the light-emitting diode.

The above described features and advantages of the present invention will be more apparent from the following description.

100, 100'‧‧‧Lighting diode structure

102‧‧‧First type doped semiconductor layer

102a‧‧‧ Platform Department

102b‧‧‧Sag

104‧‧‧Second type doped semiconductor layer

106‧‧‧Lighting layer

108, 108'‧‧‧ first electrode

Branches 108a, 108e, 110d‧‧

108b‧‧‧first mat

108c‧‧‧ opening of the first electrode

108d, 110c‧‧‧ connection segment

110‧‧‧second electrode

110a, 110a’‧‧‧ Extension

110b‧‧‧second mat

112‧‧‧Transparent conductive layer

200‧‧‧conductive bumps

300‧‧‧ boards

C‧‧‧closed area

D1, D2‧‧‧ thickness

H1‧‧‧ shortest distance

H2‧‧‧Max width

T1, T2‧‧‧ endpoint

1 is a top plan view showing a structure of a light emitting diode according to an embodiment of the present invention.

Figure 2 is a cross-sectional view taken along line A-A' of Figure 1.

Figure 3 is a cross-sectional view taken along line B-B' of Figure 1.

4 shows a light emitting diode structure bonded to a circuit board according to an embodiment of the invention. The situation.

FIG. 5 is a top plan view showing a structure of a light emitting diode according to another embodiment of the present invention.

1 is a top plan view showing a structure of a light emitting diode according to an embodiment of the present invention. Figure 2 is a cross-sectional view taken along line A-A' of Figure 1. Figure 3 is a cross-sectional view taken along line B-B' of Figure 1.

Referring to FIG. 1 , FIG. 2 and FIG. 3 , the LED structure 100 of the present embodiment includes a first type doped semiconductor layer 102 , a second type doped semiconductor layer 104 , a light emitting layer 106 , a first electrode 108 , and The second electrode 110. The light emitting layer 106 is disposed between the first type doped semiconductor layer 102 and the second type doped semiconductor layer 104. The first electrode 108 is disposed on the first type doped semiconductor layer 102, and the second electrode 110 is disposed on the second type doped semiconductor layer 104. In the present embodiment, the first type doped semiconductor layer 102 is, for example, an N type semiconductor layer, and the second type doped semiconductor layer 104 is, for example, a P type semiconductor layer. The light-emitting layer 106 is, for example, a multiple quantum well structure (MQW) in which a gallium nitride (GaN) layer and an indium gallium nitride (InGaN) layer are alternately stacked. However, in other embodiments, the luminescent layer 106 can also be a quantum well structure. The first electrode 108 and the second electrode 110 are made of a conductive material and are stacked in a single layer or a plurality of layers of conductive materials, including gold, titanium, aluminum, chromium, platinum, other conductive materials or a combination of these materials. However, the invention is not limited to the above.

In more detail, the first type doped semiconductor layer 102 of the present embodiment has The platform portion 102a and the depressed portion 102b are connected, and the thickness D1 of the land portion 102a is larger than the thickness D2 of the depressed portion 102b. The light emitting layer 106 and the second type doped semiconductor layer 104 are disposed on the land portion 102a, and the first electrode 108 is disposed on the depressed portion 102b. In an embodiment, the LED structure 100 can be packaged by means of a flip chip. As shown in FIG. 4, the present embodiment can bond the first electrode 108 and the circuit board 300 and the second electrode 110 and the circuit board 300 by using the conductive bumps 200. In this way, the user can operate the LED structure 100 of the embodiment through the circuit board 300. However, in another embodiment, the LED structure 100 can also be packaged by wire bonding, that is, the bonding wires can be used to bond the first electrode 108 and the circuit board 300 and the second electrode 110 and the circuit board. 300, while the first electrode 108 and the second electrode 110 face away from the circuit board 300.

In addition, the light emitting diode structure 100 of the embodiment may further include a transparent conductive layer 112. The transparent conductive layer 112 can be disposed between the second electrode 110 and the second type doped semiconductor layer 104. The second type doped semiconductor layer 104 can form a good ohmic contact with the second electrode 110 by the transparent conductive layer 112. The material of the transparent conductive layer 112 is, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (indium tin zinc). Oxide, ITZO), aluminum tin oxide (ATO), aluminum zinc oxide (AZO) or other suitable transparent conductive material.

The first electrode 108 of the embodiment includes a plurality of branch portions 108a, and the second electrode 110 of the embodiment encloses at least one closed region C (FIG. 1 is a seal) Closed area C is an example). For example, as shown in FIG. 1, the first electrode 108 of the present embodiment includes two branch portions 108a. (In FIG. 1 , the two branch portions 108 a are taken as an example. However, the structure of the light emitting diode of the present invention is not limited to that shown in FIG. 1 . In other embodiments, the first electrode 108 may include three or more. Branch portion 108a).

In the present embodiment, the closed area C is located between the adjacent two branch portions 108a. In this embodiment, the shortest distance H1 between each branch portion 108a and the adjacent second electrode 110 is less than or equal to the maximum width H2 of the closed region C, but the present invention is not limited thereto, and the distance H1 and the maximum width H2 are both Adjustable to the design needs of the implementation. The maximum width H2 herein refers to the direction in which the width of one closed region C is the largest in each of the different directions, and the width of the closed region C in this direction is the maximum width H2.

The electrode design described above (i.e., the closed region C is located between the adjacent two branch portions 108a) can improve the problem of poor luminous efficiency due to the difference in electron and hole mobility in the prior art. The details are as follows: Since the electron mobility is faster than that of the hole, the electrons can maintain a high concentration away from the branch portion 108a. Therefore, when the electrons move to the closed region C, the concentration of the electrons and the concentration of the holes are relatively close, so that the electrons and the holes have a better recombination ratio, thereby improving the luminous efficiency of the light-emitting diode structure 100.

In this embodiment, since the shortest distance H1 between each branch portion 108a and the adjacent second electrode 110 is less than or equal to the maximum width H2 of the closed region C, the electron concentration in the closed region C can be effectively improved. The concentration of the electrons is closer to the concentration of the holes, and the ratio of the electrons to the holes is increased. The luminous efficiency of the light emitting diode structure 100 is improved.

In the closed region C of the light-emitting diode structure 100 of the present embodiment, the distance between the closed region C and the branch portion 108a is long, and thus the electron emission from the branch portion 108a is transmitted to the closed region C, and the electron concentration has decreased. On the other hand, although the distance between the closed region C and the second electrode 110 is relatively close, since the mobility of the hole is smaller than that of the electron, when the hole emitted by the second electrode 110 is transmitted to the closed region C, the electricity is generated. The hole concentration has dropped to a level close to the electron concentration. In this way, the concentration of the holes in the closed region C can be matched with the concentration of electrons in the closed region C, thereby further increasing the probability of recombination of the electron holes in and around the closed region C, and further increasing The luminous efficiency of the light emitting diode structure 100 is improved, and the uniformity of light emission of the light emitting diode structure 100 can also be improved.

Referring to FIG. 1 , FIG. 3 and FIG. 4 , the first electrode 108 of the embodiment may further include at least one first pad 108 b , and the first pad 108 b is connected to the branch portion 108 a. The second electrode 110 of this embodiment may further include at least one second pad 110b and one extension portion 110a connected to the second pad 110b. In this embodiment, the second pad 110b and the extension portion 110a enclose the closed area C. In addition, in the embodiment, the second pads 110b are disposed between the adjacent two branch portions 108a of the first electrode 108. As shown in FIG. 4, the first pads 108b and the second pads 110b are connected to the circuit board 300 through the conductive bumps 200, thereby allowing the user to operate the LED structure 100 through the circuit board 300.

In detail, the branch portion 108a of the embodiment has opposite first and second ends T1 and T2, and the first pad 108b connects the first end of the adjacent branch 108a. T1. In the present embodiment, the first one of the first electrodes 108 has a U-shape, and the second electrode 110 has a ring shape. Also, the U-shaped opening 108c of the first electrode 108 faces the second pad 110b of the second electrode 110.

FIG. 5 is a top plan view showing a structure of a light emitting diode according to another embodiment of the present invention. Referring to Fig. 5, the light emitting diode structure 100' of the present embodiment is similar to the light emitting diode structure 100 of Fig. 1, and the difference between the two is as follows. In this embodiment, the first electrode 108' includes a plurality of first pads 108b, and the first electrode 108' further includes at least one connecting portion 108d and a plurality of branch portions 108e, wherein the connecting portion 108d connects the adjacent two first portions. The pads 108b are extended by the first pads 108b. Further, in the present embodiment, the second electrode 110' includes a plurality of second pads 110b, an extension portion 110a', a plurality of connection segments 110c, and a plurality of branch portions 110d. The extending portion 110a' is, for example, annular, and the connecting portion 110c connects the extending portion 110a' and the second pad 110b, and the second pads 110b extend out of the branch portion 110d, respectively. In the present embodiment, the branch portion 110d is disposed between the branch portion 108e and the branch portion 108a. Alternatively, in another embodiment, the branch portion 110d and the branch portion 108e may be alternately arranged. In the present embodiment, since the extending portion 110a' is annular and encloses the closed region C, it also has an effect similar to that of the light-emitting diode structure 100 of Fig. 1, and will not be repeated here.

In summary, the light-emitting diode structure of the present invention enables electronic electricity on various regions of the light-emitting diode structure by arranging a second electrode surrounding the closed region between adjacent two branch portions of the first electrode. The hole concentration is matched, which can effectively promote the recombination of electrons and holes, thereby increasing the probability of electron hole compounding. As such, the present invention The luminous efficiency of the light-emitting diode structure can be effectively improved.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Lighting diode structure

102b‧‧‧Sag

108‧‧‧First electrode

108a‧‧‧ Branch

108b‧‧‧first mat

108c‧‧‧ opening of the first electrode

110‧‧‧second electrode

110a‧‧‧Extension

110b‧‧‧second mat

112‧‧‧Transparent conductive layer

C‧‧‧closed area

H1‧‧‧ shortest distance

H2‧‧‧Max width

T1, T2‧‧‧ endpoint

Claims (13)

A light emitting diode structure comprising: a first type semiconductor layer; a first electrode disposed on the first type semiconductor layer, the first electrode comprising a plurality of first branch portions; a second type semiconductor layer; a second electrode disposed on the second type semiconductor layer, the second electrode includes a plurality of second branch portions and at least one extending portion, the extending portion has two extending arms, and a light emitting layer disposed on the first electrode Between the semiconductor layer and the second semiconductor layer, wherein the second branch portion and the extending portion respectively extend between two adjacent first branch portions, and the two extending arms of the extending portion The first electrode is not disposed between the two adjacent portions, and the second branch portion and the two adjacent portions of the extension portion are disposed between the two adjacent portions. One of the first branches. A light emitting diode structure comprising: a first type semiconductor layer; a first electrode disposed on the first type semiconductor layer, the first electrode comprising a plurality of first branch portions; a second type semiconductor layer; a second electrode disposed on the second type semiconductor layer, the second electrode includes a plurality of second branch portions and at least one extension portion, the extension portion having two extension arms; And a light emitting layer disposed between the first type semiconductor layer and the second type semiconductor layer, wherein the first electrode is disposed in an area where the first type semiconductor layer is exposed by the light emitting layer and the second type semiconductor layer The first branch portions of the first electrode and the second branch portion of the second electrode and the extending portion are opposite to each other and are staggered with each other, and the region between the two extending arms of the extending portion is not disposed a first electrode, and the extending portion is located between the two adjacent first branch portions, and the first branch portion is disposed between the two second branch portions and any two adjacent ones of the extending portions One. A light emitting diode structure comprising: a first type semiconductor layer; a first electrode disposed on the first type semiconductor layer, the first electrode comprising a plurality of first branch portions; a second type semiconductor layer; a second electrode disposed on the second type semiconductor layer, the second electrode includes a plurality of second branch portions and at least one extending portion, the extending portion has two extending arms, and a light emitting layer disposed on the first electrode Between the semiconductor layer and the second type semiconductor layer, wherein a distance between the extension arms of the extension portion and the first branch portions is smaller than a distance between the extension arms, the two extensions of the extension portion The first electrode is not disposed in the region between the arms, and the extension portion is located between the two adjacent first branch portions, and the second branch portion and the two adjacent portions of the extension portion are disposed between One of the first branches. A light emitting diode structure includes: an epitaxial structure, comprising a first type semiconductor layer, a light emitting layer and a second type semiconductor layer; and a first electrode and a second electrode The same side of the crystal structure, wherein the first electrode is disposed on the first type semiconductor layer and has a plurality of first branch portions, the second electrode is disposed on the second type semiconductor layer, and has an extension portion and a plurality of second branch portions, each of which is disposed with an equal number of portions of the second branch portions, wherein the first branch portions of the first electrode and the extension portion of the second electrode The second branch portions extend toward each other and are arranged in a finger-crossing manner, the extending portion is located between two adjacent first branch portions, and the second branch portions and the two adjacent portions of the extending portion are between One of the first branch portions is disposed, wherein the extension portion has two extension arms, and the first electrode is not disposed in a region between the two extension arms. An LED structure includes: an epitaxial structure, comprising a first type semiconductor layer, a light emitting layer and a second type semiconductor layer; a first electrode disposed on the first type semiconductor layer; And having a plurality of first branch portions extending from a first side to an opposite second side; and a second electrode disposed on the second type semiconductor layer and having the first side to the first side An extending portion and a plurality of second branch portions extending substantially in the center of the second type semiconductor layer and having two extending arms, the extending arms There is an intersection closer to the second side, wherein the extension portion is located between two adjacent first branch portions, and the intersection is located at the two adjacent first branch portions and the end points thereof Outside the range covered, and the area between the two extension arms is not provided with the first electrode. An LED structure includes: an epitaxial structure, comprising a first type semiconductor layer, a light emitting layer and a second type semiconductor layer; a first electrode disposed on the first type semiconductor layer; And having a plurality of first branch portions; and a second electrode disposed on the second type semiconductor layer and having an extension portion and a plurality of second branch portions, the extension portion having two extension arms, wherein each of the above The extending arm and the adjacent one of the second branch portions sandwich one of the first branch portions, and the first branch portion is disposed between any two of the second branch portion and the extending portion First, and the region between the extension arms is not provided with the first electrode. The light emitting diode structure according to any one of claims 1 to 6, wherein the first type semiconductor layer has a platform portion and a lower trap portion, the thickness of the platform portion being greater than the depressed portion The light-emitting layer and the second-type semiconductor layer are disposed on the platform portion, and the first electrode is disposed on the depressed portion. The light emitting diode structure according to any one of claims 1 to 6, wherein the first electrode further comprises at least one first pad, the first pad electrical property The second branch portion is connected to the first branch portion, and the second electrode further includes at least one second pad electrically connected to the extension portion and the second branch portions. The illuminating diode structure of claim 8, wherein the second pad is disposed between the two first branch portions adjacent to the first electrode. The light emitting diode structure of claim 8, wherein the first branch portions of the first electrode are U-shaped, and the ends of the two extending arms of the extending portion are connected The elongated ring shape, the U-shaped opening of the first electrode faces the second pad of the second electrode. The light emitting diode structure according to any one of claims 1 to 6, wherein the light emitting diode structure is used for a flip chip package. The light emitting diode structure according to any one of claims 1 to 6, further comprising a transparent conductive layer disposed between the second electrode and the second type semiconductor layer. The light emitting diode structure according to any one of claims 1 to 6, wherein a shortest distance between each of the first branch portions and an adjacent second electrode is less than or equal to the extensions The maximum width between the arms.