TW201803155A - Light emitting diode structure - Google Patents

Abstract

A light emitting diode structure including a first type doped semiconductor layer, a second type doped semiconductor layer, a light emitting layer, a first electrode, and a second electrode is provided. 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 first branches. The second electrode is disposed on the second type doped semiconductor layer. The second electrode encircles at least one closed area, and the closed area is located between two adjacent first branches.

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 electrode design of the conventional light-emitting diode structure has the disadvantage of causing poor current dispersion, making this electrode design unsuitable for use in 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, since the mobility of electrons and holes is different, the mobility of electrons is faster than the mobility of holes, so since the first When the electrons emitted from the branch portion are transmitted to the second branch portion (or when the hole from the second branch portion is transmitted to the first branch portion), the electron concentration and the hole near the second branch portion (or beside the first branch portion) The concentration difference is extremely large, and the electron and hole recombination probability is low, so that the light-emitting diode structure having such a conventional electrode has poor luminous efficiency.

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 extend opposite to and extend from the second branch portions and the extension portions of the second electrode, and the extension portion encloses 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.

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 connected land portion 102a and the depressed portion 102b, 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 present embodiment includes a plurality of branch portions 108a, and the second electrode 110 of the present embodiment encloses at least one closed region C (FIG. 1 is an example of a closed region C). 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 distance H2 are both visible. Adjusted for the design requirements 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 luminous efficiency of the light-emitting diode structure 100 is improved by increasing the recombination ratio of the electrons and the holes.

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 present embodiment has opposite first and second ends T1 and T2, and the first pad 108b connects the first end T1 of the adjacent branch portion 108a. 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. In this way, the luminous efficiency of the luminous efficiency of the light-emitting diode structure of the present invention 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, 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. Fig. 4 shows a state in which the light emitting diode structure of one embodiment of the present invention is bonded to a circuit board. FIG. 5 is a top plan view showing a structure of a light emitting diode according to another embodiment of the present invention.

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 (6)

A light emitting diode structure comprising: a first type doped semiconductor layer; a second type doped semiconductor layer; an illuminating layer disposed on the first type doped semiconductor layer and the second type doped semiconductor layer a first electrode disposed on the first type doped semiconductor layer, the first electrode includes at least one first pad portion and at least one first branch portion, the first pad portion connecting the first electrode a second electrode disposed on the second type doped semiconductor layer, the second electrode including at least one second pad portion, at least one second branch portion, at least one second connection portion, and at least one An extension portion, wherein the second connection portion connects the second pad portion and the second branch portion, the at least one extension portion is disposed at a region between two opposite parallel sides of the LED structure, wherein the extension portion There are two extension arms, and no electrodes are provided between the extension arms. A light emitting diode structure comprising: a first type doped semiconductor layer; a second type doped semiconductor layer; an illuminating layer disposed on the first type doped semiconductor layer and the second type doped semiconductor layer a first electrode disposed on the first type doped semiconductor layer, the first electrode includes at least one first pad portion, at least one first branch portion, and at least one first connection portion, the first The connecting portion is connected to the first pad portion and the first branch portion; and a second electrode is disposed on the second type doped semiconductor layer, the second electrode includes at least one second pad portion, at least one a second branch portion, at least one second connecting portion, and at least one extending portion, wherein the second connecting portion is connected to the second pad portion and the second branch portion, wherein the at least one extending portion is disposed on the LED structure The extension portion has two extension arms, and two electrodes are not disposed between the extension arms, wherein the second connection portion further connects the second pad portion and the extension portion. A light emitting diode structure comprising: a first type doped semiconductor layer; a second type doped semiconductor layer; an illuminating layer disposed on the first type doped semiconductor layer and the second type doped semiconductor layer a first electrode disposed on the first type doped semiconductor layer, the first electrode includes at least one first pad portion and at least one first branch portion, the first pad portion connecting the first electrode a second electrode disposed on the second type doped semiconductor layer, the second electrode includes a plurality of second pads, at least one second connection, and at least one extension, wherein the second The connecting portion is connected to the second pad portions, and the at least one extending portion is disposed at a region between the two adjacent first branch portions, wherein the extending portion has two extending arms, and no two are disposed between the extending arms electrode. A light emitting diode structure comprising: a first type doped semiconductor layer; a second type doped semiconductor layer; an illuminating layer disposed on the first type doped semiconductor layer and the second type doped semiconductor layer a first electrode disposed on the first type doped semiconductor layer, the first electrode includes at least one first pad portion, at least one first branch portion, and at least one first connection portion, wherein the first electrode a connecting portion connecting the first pad portion and the first branch portion; and a second electrode disposed on the second type doped semiconductor layer, the second electrode comprising a plurality of second pad portions, at least one a second branching portion, at least one second connecting portion, and at least one extending portion, wherein the second connecting portion is connected to the second connecting portions, and the at least one extending portion is disposed between the two adjacent first branch portions a region, wherein the extension has two extension arms, and no electrodes are disposed between the extension arms. The light emitting diode structure according to any one of claims 1 to 4, wherein at least one of the first electrode and the second electrode surrounds an open region. The light emitting diode structure according to any one of claims 1 to 4, wherein the first type doped semiconductor layer has a platform portion and a lower trap portion, the light emitting layer and the second layer The doped semiconductor layer is disposed on the platform portion, and the first electrode is disposed on the depressed portion, and an upper surface of the first electrode does not exceed an upper surface of the light emitting layer.