Light emitting diode capable of maintaining forward voltage

Abstract

The invention provides a light emitting diode capable of maintaining forward voltage, and belongs to the technical field of photoelectron manufacturing. The light-emitting diode comprises an epitaxial layer, a transparent conductive layer, a first electrode and a second electrode, the epitaxial layer comprises a light-emitting area and a non-light-emitting area, the first electrode is located in the non-light-emitting area, the transparent conductive layer is located in the light-emitting area, and the second electrode is located on the surface, away from the epitaxial layer, of the transparent conductive layer; the ratio of the minimum distance from the peripheral edge of the transparent conductive layer to the peripheral edge of the light-emitting area to the shortest distance between the first electrode and the second electrode is 0.06-0.08. According to the embodiment of the invention, the forward voltage can be kept stable and unchanged under the condition that the distance between the P electrode and the N electrode is increased.

Description

Technical Field

[0001] The present disclosure relates to the field of optoelectronic manufacturing technology, and in particular to a light emitting diode capable of maintaining a forward voltage. Background Art

[0002] Light-emitting diodes (LEDs) are a highly influential new product in the optoelectronics industry. For indoor fine-pitch display LED chips, the market is urgently demanding reduced chip size to lower production costs.

[0003] As LED chips continue to shrink, the center-to-center distance between the P and N electrodes decreases dramatically. This change leads to collisions between solder balls during the wire bonding process. To address this issue, a common approach is to increase the center-to-center distance between the P and N electrodes.

[0004] However, as the distance between the P and N electrodes increases, the forward voltage of the LED chip also increases. Excessively high forward voltage will cause more non-radiative recombination inside the LED chip, reducing the number of photons emitted and lowering the luminous efficiency. Summary of the Invention

[0005] The present disclosure provides a light-emitting diode that maintains a forward voltage, which can maintain a stable forward voltage even when the distance between the P electrode and the N electrode is increased. The technical solution is as follows:

[0006] On the one hand, an embodiment of the present disclosure provides a light-emitting diode, which includes: an epitaxial layer, a transparent conductive layer, a first electrode, and a second electrode, the epitaxial layer including a light-emitting area and a non-light-emitting area; the ratio of the minimum distance from the peripheral edge of the transparent conductive layer to the peripheral edge of the light-emitting area to the shortest distance between the first electrode and the second electrode is 0.06 to 0.08.

[0007] Optionally, a ratio of the shortest distance between the first electrode and the second electrode to the length of the long side of the epitaxial layer is 0.2 to 0.25.

[0008] Optionally, a ratio of the shortest distance from the first electrode to the light-emitting area to the shortest distance between the first electrode and the second electrode is 0.3 to 0.45.

[0009] On the other hand, an embodiment of the present disclosure provides a light-emitting diode, which includes: an epitaxial layer, a first electrode, and a second electrode, the epitaxial layer including a light-emitting area and a non-light-emitting area; the positive projection of the side of the light-emitting area close to the first electrode on the epitaxial layer includes a first arc segment, a second arc segment, and a third arc segment connected in sequence, the first arc segment and the third arc segment are both bent toward the direction of the first electrode, and the second arc segment is bent away from the first electrode.

[0010] Optionally, the radii of the first arc segment and the third arc segment are the same; and the ratio of the radius of the first arc segment to the length of the short side of the epitaxial layer is 0.1 to 0.16.

[0011] Optionally, a ratio of the radius of the second arc segment to the length of the short side of the epitaxial layer is 0.34 to 0.46.

[0012] On the other hand, an embodiment of the present disclosure provides a light-emitting diode, comprising: an epitaxial layer, the epitaxial layer comprising a light-emitting area and a non-light-emitting area; the orthographic projection of the light-emitting area on the epitaxial layer is proportionally magnified by 0.9 to 1.1 times and is located within a closed curve, the closed curve comprising 8 end-to-end connected trajectory segments Si, 1≤i≤8; wherein, trajectory segments S1, S3, S4, S5 and S7 are circular arcs, and trajectory segments S2, S6 and S8 are straight lines.

[0013] Optionally, in a coordinate system with the first end of the trajectory segment S1 as the origin, the direction parallel to the long side of the light-emitting diode as the X-axis, and the direction perpendicular to the long side of the light-emitting diode as the Y-axis; the functions of the trajectory segments S1, S3, S4, S5 and S7 are:

[0014] X=X0+Rcosα

[0015] Y=Y0+Rsinα

[0016] Where X0 and Y0 are the centers of the arc, R is the radius of the arc, and α is the angle corresponding to any point in the arc.

[0017] The values ​​of R of the trajectory segments S1, S3, S4, S5, and S7 are 9.0 μm, 9.0 μm, 28.0 μm, 9.0 μm, and 9.0 μm, respectively.

[0018] Optionally, the value ranges of α of the trajectory segments S1, S3, S4, S5 and S7 are: 180.0° to 270.0°, 31.8° to 270.0°, 148.2° to 211.8°, 90.0° to 328.2° and 90.0° to 180.0°, respectively.

[0019] Optionally, the rotation directions of the track segments S1 , S3 , S4 , S5 and S7 are respectively: counterclockwise, counterclockwise, clockwise, counterclockwise and counterclockwise.

[0020] The beneficial effects of the technical solutions provided by the embodiments of the present disclosure include at least:

[0021] In the light-emitting diode provided by the embodiments of the present disclosure, a transparent conductive layer is disposed in the light-emitting region of the epitaxial layer, a second electrode is disposed on the transparent conductive layer, and a first electrode is disposed in the non-light-emitting region of the epitaxial layer. Furthermore, the ratio of the minimum distance between the peripheral edge of the transparent conductive layer and the peripheral edge of the light-emitting region to the shortest distance between the first electrode and the second electrode is 0.06 to 0.08. This allows the spacing between the transparent conductive layer and the peripheral edge of the light-emitting region to be correlated with the spacing between the two electrodes. Even if the spacing between the two electrodes is increased, the spacing between the peripheral edge of the transparent conductive layer and the peripheral edge of the light-emitting region is limited to a predetermined range, thereby preventing a significant decrease in the spacing between the peripheral edge of the transparent conductive layer and the peripheral edge of the light-emitting region. The closer the peripheral edge of the transparent conductive layer is to the peripheral edge of the light-emitting region, the larger the area of ​​the transparent conductive layer. The larger the area of ​​the transparent conductive layer, the smaller the equivalent resistance of the current diffusion path, and thus the lower the forward voltage of the light-emitting diode. Therefore, the distance between the transparent conductive layer and the peripheral edge of the light-emitting area is correlated with the distance between the two electrodes. When the distance between the two electrodes increases, the area of ​​the transparent conductive layer can be controlled within a reasonable range, thereby ensuring that the forward voltage of the light-emitting diode remains stable, avoiding the generation of more non-radiative recombination inside the light-emitting diode, and improving the luminous efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 is a top view of a light emitting diode provided by an embodiment of the present disclosure;

[0024] Figure 2 is a cross-sectional view of a light emitting diode provided by an embodiment of the present disclosure;

[0025] Figure 3 is a top view of an epitaxial layer provided by an embodiment of the present disclosure;

[0026] Figure 4 is a top view of a transparent conductive layer provided by an embodiment of the present disclosure;

[0027] Figure 5This is a test data diagram of a light emitting diode provided by an embodiment of the present disclosure;

[0028] Figure 6 This is a flow chart of a method for preparing a light emitting diode provided in an embodiment of the present disclosure.

[0029] The descriptions of the marks in the figure are as follows:

[0030] 10. Substrate;

[0031] 20. epitaxial layer; 21. first semiconductor layer; 22. active layer; 23. second semiconductor layer; 24. groove;

[0032] 201, luminous area; 2011, first arc segment; 2012, second arc segment; 2013, third arc segment;

[0033] 202, non-luminous area;

[0034] 31. First electrode; 32. Second electrode;

[0035] 40. Transparent conductive layer;

[0036] 50. Passivation layer. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0038] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by a person of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," "third," and similar words used in the patent specification and claims of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish between different components. Similarly, terms such as "a" or "an" do not indicate a quantitative limitation, but rather indicate the presence of at least one. Terms such as "include" or "comprise" mean that the elements or objects preceding "include" or "comprises" encompass the elements or objects listed after "include" or "comprises," and their equivalents, and do not exclude other elements or objects. Terms such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," "right," "top," and "bottom" are used only to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0039] Figure 1 This is a top view of a light emitting diode provided by an embodiment of the present disclosure. Figure 2It is a cross-sectional view of a light-emitting diode provided by an embodiment of the present disclosure. Figure 2 It is along Figure 1 Cross-sectional view taken along section line AB.

[0040] like Figure 1 、 2 As shown, the light-emitting diode includes: an epitaxial layer 20, a transparent conductive layer 40, a first electrode 31 and a second electrode 32. The epitaxial layer 20 includes a light-emitting area 201 and a non-light-emitting area 202. The first electrode 31 is located in the non-light-emitting area 202. The transparent conductive layer 40 is located in the light-emitting area 201. The second electrode 32 is located on the surface of the transparent conductive layer 40 away from the epitaxial layer 20.

[0041] The ratio of the minimum distance a from the peripheral edge of the transparent conductive layer 40 to the peripheral edge of the light emitting area 201 to the shortest distance b between the first electrode 31 and the second electrode 32 is 0.06 to 0.08.

[0042] In the light-emitting diode provided by the embodiments of the present disclosure, a transparent conductive layer 40 is disposed in the light-emitting region 201 of the epitaxial layer 20, a second electrode 32 is located on the transparent conductive layer 40, and a first electrode 31 is located in the non-light-emitting region 202 of the epitaxial layer 20. Furthermore, the ratio of the minimum distance from the peripheral edge of the transparent conductive layer 40 to the peripheral edge of the light-emitting region 201 to the shortest distance between the first electrode 31 and the second electrode 32 is 0.06 to 0.08. This ensures that the spacing between the transparent conductive layer 40 and the peripheral edge of the light-emitting region 201 is correlated with the spacing between the two electrodes. Even if the spacing between the two electrodes is increased, the spacing between the peripheral edge of the transparent conductive layer 40 and the peripheral edge of the light-emitting region 201 remains within a predetermined range, thereby preventing a significant reduction in the spacing between the peripheral edge of the transparent conductive layer 40 and the peripheral edge of the light-emitting region 201. The closer the edge of the transparent conductive layer 40 is to the edge of the light-emitting region 201, the larger the area of ​​the transparent conductive layer 40. The larger the area of ​​the transparent conductive layer 40, the smaller the equivalent resistance of the current diffusion path, and thus the lower the forward voltage of the LED. Therefore, the distance between the transparent conductive layer 40 and the edge of the light-emitting region 201 is correlated with the distance between the two electrodes. When the distance between the two electrodes is increased, the area of ​​the transparent conductive layer 40 can be controlled within a reasonable range, thereby ensuring a stable forward voltage of the LED and preventing excessive non-radiative recombination within the LED, thereby improving luminous efficiency.

[0043] In the disclosed embodiment, the pattern formed by the peripheral edge of the transparent conductive layer 40 is similar to the pattern formed by the peripheral edge of the light-emitting area 201, and the shortest distance from any point on the peripheral edge of the transparent conductive layer 40 to the peripheral edge of the light-emitting area 201 is the same.

[0044] The shortest distance between the first electrode 31 and the second electrode 32 is a straight-line distance between the shortest two points on the outer contour of the first electrode 31 and the outer contour of the second electrode 32 .

[0045] For example, the minimum distance from the peripheral edge of the transparent conductive layer 40 to the peripheral edge of the light-emitting area 201 is 2 μm, and the shortest distance between the first electrode 31 and the second electrode 32 is 28 μm. The ratio of the minimum distance from the peripheral edge of the transparent conductive layer 40 to the peripheral edge of the light-emitting area 201 to the shortest distance between the first electrode 31 and the second electrode 32 is 0.07.

[0046] Optionally, a ratio of the shortest distance b between the first electrode 31 and the second electrode 32 to the length c of the long side of the epitaxial layer 20 is 0.2 to 0.25.

[0047] In the embodiment of the present disclosure, the outer contour of the epitaxial layer 20 may be a rectangle, and the long side of the epitaxial layer 20 is the side with a longer length on the outer contour of the epitaxial layer 20 .

[0048] For example, the shortest distance between the first electrode 31 and the second electrode 32 is 28 μm, the long side length of the epitaxial layer 20 is 125 μm, and the ratio of the shortest distance between the first electrode 31 and the second electrode 32 to the long side length of the epitaxial layer 20 is 0.224.

[0049] When the ratio of the electrode spacing to the length of the epitaxial layer 20 is too small, current will be excessively concentrated below the electrodes, causing localized heating and reduced luminous efficiency. A large ratio can increase equivalent resistance and affect voltage characteristics. By controlling the minimum distance between the first electrode 31 and the second electrode 32 to within 0.2 to 0.25 of the length of the long side of the epitaxial layer 20, the resistance of lateral current expansion and longitudinal current transmission is balanced, reducing current crowding near the electrodes and effectively spreading current to the light-transmitting areas of the epitaxial layer 20, thereby improving luminous efficiency.

[0050] Furthermore, setting the spacing between the first electrode 31 and the second electrode 32 within an appropriate range can also reduce the electric field strength between the two electrodes, reducing the risk of electrostatic breakdown. This can also prevent metal migration short circuits caused by a too small spacing between the electrodes. Furthermore, by limiting the spacing between the two electrodes, heat accumulation caused by excessive local current density can be reduced, lowering the chip's temperature gradient.

[0051] Optionally, a ratio of the shortest distance e from the first electrode 31 to the light emitting area 201 to the shortest distance b between the first electrode 31 and the second electrode 32 is 0.3 to 0.45.

[0052] For example, the shortest distance between the first electrode 31 and the light emitting region 201 is 10 μm, and the shortest distance between the first electrode 31 and the second electrode 32 is 28 μm. The ratio of the shortest distance from the first electrode 31 to the light emitting region 201 to the shortest distance between the first electrode 31 and the second electrode 32 is 0.36.

[0053] By limiting the minimum distance between the first electrode 31 and the light-emitting region 201 to within the aforementioned range, the layout of the first electrode 31 is optimized. When the first electrode 31 is close to the light-emitting region 201, the electron injection path is shortened, reducing series resistance. Maintaining a certain distance between the first electrode 31 and the light-emitting region 201 prevents excessive current concentration, ensuring a more uniform distribution of carriers within the light-emitting region 201 and improving luminous efficiency. This also prevents a situation where the distance between the first electrode 31 and the light-emitting region 201 is too small, causing the first electrode 31 to be too close to the active layer 22 and increasing the electrode's light absorption area. It also prevents a situation where the distance between the first electrode 31 and the light-emitting region 201 is too large, causing insufficient lateral current expansion and causing localized overheating.

[0054] Alternatively, as Figure 1 As shown, the light emitting diode includes: an epitaxial layer 20 , a first electrode 31 and a second electrode 32 . The epitaxial layer 20 includes a light emitting region 201 and a non-light emitting region 202 .

[0055] The positive projection of the side of the light-emitting area 201 close to the first electrode 31 on the epitaxial layer 20 includes a first arc segment 2011, a second arc segment 2012 and a third arc segment 2013 connected in sequence. The first arc segment 2011 and the third arc segment 2013 are both bent toward the direction of the first electrode 31, and the second arc segment 2012 is bent away from the first electrode 31.

[0056] In the embodiment of the present disclosure, the first arc segment 2011 and the second arc segment 2012 are both curved toward the side where the first electrode 31 is located, which can increase the area of ​​the light-emitting region 201 and thus enhance the light-emitting effect of the light-emitting diode.

[0057] Among them, the side wall of the first electrode 31 close to the light-emitting area 201 is an arc surface. By bending the second arc segment 2012 in a direction away from the second electrode 32, the second arc segment 2012 can form a concentric arc with the side wall of the first electrode 31 close to the light-emitting area 201. In this way, the distance from each position on the second arc segment 2012 to the first electrode 31 is the same, which can facilitate the control of the shortest distance from the first electrode 31 to the light-emitting area 201 within the design requirements.

[0058] At the same time, by setting the side of the light-emitting area 201 as an arc segment, the sharp corners of the active layer 22 are eliminated, preventing excessive concentration of the electric field at the tips. The arc segment can also alleviate stress concentration at the corners of the epitaxial layer 20, reducing the risk of cracks caused by thermal expansion or packaging stress.

[0059] Optionally, the radii of the first arc segment 2011 and the third arc segment 2013 are the same; and the ratio of the radius of the first arc segment 2011 to the length d of the short side of the epitaxial layer 20 is 0.1 to 0.16.

[0060] For example, the radius R of the first arc segment 2011 is 9 μm, the short side length d of the epitaxial layer 20 is 70 μm, and the ratio of the radius of the first arc segment 2011 to the short side length d of the epitaxial layer 20 is 0.13.

[0061] When the radius of first arc segment 2011 exceeds 5 μm, carrier aggregation is dispersed, improving forward antistatic capabilities and reducing the risk of leakage or breakdown. Furthermore, the radius of first arc segment 2011 is proportional to the short side of epitaxial layer 20, avoiding the tip effect and controlling the loss of light-emitting area. It also provides a smoother gradient of the electric field along the corners, improving carrier recombination uniformity.

[0062] Optionally, the ratio of the radius of the second arc segment 2012 to the length of the short side of the epitaxial layer 20 is 0.34 to 0.46.

[0063] For example, the radius of the second arc segment 2012 is 28 μm, the short side length of the epitaxial layer 20 is 70 μm, and the ratio of the radius of the second arc segment 2012 to the short side length of the epitaxial layer 20 is 0.4.

[0064] The ratio of the radius of the second arc segment 2012 to the length of the short side of the epitaxial layer 20 is controlled within the above-mentioned range, so that the second arc segment 2012 can occupy a larger area, and the second arc segment 2012 can surround the side wall of the first electrode 31 close to the light-emitting area 201 within a larger angle range, so that the distance from each position on the side wall of the first electrode 31 facing the light-emitting area 201 to the second arc segment 2012 is the same.

[0065] Alternatively, as Figure 2 As shown, the light emitting diode further includes a substrate 10 , and an epitaxial layer 20 is located on the surface of the substrate 10 .

[0066] For example, the substrate is a sapphire substrate. Sapphire substrates have high light transmittance, meaning they are transparent. Furthermore, sapphire is a relatively hard material with relatively stable chemical properties, which enables the LED to have good luminous effects and stability.

[0067] Alternatively, as Figure 2 As shown, the epitaxial layer 20 includes a first semiconductor layer 21 , an active layer 22 and a second semiconductor layer 23 stacked in sequence. The surface of the second semiconductor layer 23 has a groove 24 exposing the first semiconductor layer 21 .

[0068] The area where the first semiconductor layer 21 is exposed by the groove 24 is the non-luminescent area 202 on the epitaxial layer 20 , and the area where the second semiconductor layer 23 is exposed is the luminescent area 201 .

[0069] The transparent conductive layer 40 is located on the surface of the second semiconductor layer 23 , the second electrode 32 is located on the surface of the transparent conductive layer 40 , the first electrode 31 is located in the groove 24 , and the first electrode 31 is connected to the first semiconductor layer 21 .

[0070] In the embodiment of the present disclosure, one of the first semiconductor layer 21 and the second semiconductor layer 23 is a p-type layer, and the other of the first semiconductor layer 21 and the second semiconductor layer 23 is an n-type layer.

[0071] As an example, the first semiconductor layer 21 is an n-type layer, and the second semiconductor layer 23 is a p-type layer.

[0072] Optionally, the first semiconductor layer 21 is a silicon-doped n-type GaN layer, and the thickness of the n-type GaN layer may be 0.5 μm to 3 μm.

[0073] Optionally, the active layer 22 includes alternately grown InGaN quantum well layers and GaN quantum barrier layers, wherein the active layer 22 may include 3 to 8 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0074] As an example, in the embodiment of the present disclosure, the active layer 22 includes five periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0075] Optionally, the thickness of the active layer 22 may be 150 nm to 200 nm.

[0076] Optionally, the second semiconductor layer 23 is a magnesium-doped p-type GaN layer, and the thickness of the p-type GaN layer may be 0.5 μm to 3 μm.

[0077] The first electrode 31 located in the groove 24 is an n-electrode, and the electrode located on the second semiconductor layer 23 is a p-electrode.

[0078] Alternatively, as Figure 2 As shown, the light emitting diode further includes a passivation layer 50 , which is located at least on the surface of the second semiconductor layer 23 , the surface of the transparent conductive layer 40 and the bottom surface of the groove 24 .

[0079] Illustratively, the passivation layer 50 has through holes exposing the first semiconductor layer 21 and the transparent conductive layer 40 respectively. The first electrode 31 is connected to the first semiconductor layer 21 through the through hole, and the second electrode 32 is connected to the transparent conductive layer 40 through the through hole.

[0080] Alternatively, the passivation layer 50 may include a DBR layer or a silicon oxide layer.

[0081] Optionally, the light emitting diode includes an epitaxial layer 20, wherein the epitaxial layer 20 includes a light emitting region 201 and a non-light emitting region 202. The orthographic projection of the light emitting region 201 on the epitaxial layer 20 is proportionally magnified by 0.9 to 1.1 times and lies within a closed curve.

[0082] Figure 3 FIG. 1 is a top view of an epitaxial layer 20 provided in an embodiment of the present disclosure. Figure 3 As shown, the closed curve includes 8 end-to-end track segments Si, 1≤i≤8.

[0083] like Figure 3 As shown, the trajectory segments S1 , S3 , S4 , S5 and S7 are arcs, and the trajectory segments S2 , S6 and S8 are straight lines.

[0084] The first end of the trajectory segment S1 (such as Figure 3 In a coordinate system where the left end of the midline segment S1 is the origin, the direction parallel to the long side of the epitaxial layer 20 is the X axis, and the direction perpendicular to the long side of the epitaxial layer 20 is the Y axis, the trajectory function of each arc is:

[0085] X=X0+Rcosα;

[0086] Y=Y0+Rsinα;

[0087] Where X0 and Y0 are the arc centers, R is the arc radius, and α is the independent variable, representing the angle corresponding to any point in the arc. Each arc is defined by its starting point α1, its ending point α2, and its rotational direction. The values ​​of R for trajectory segments S1, S3, S4, S5, and S7 are 9.0 μm, 9.0 μm, 28.0 μm, 9.0 μm, and 9.0 μm, respectively. The ranges of α for trajectory segments S1, S3, S4, S5, and S7 are 180.0° to 270.0°, 31.8° to 270.0°, 148.2° to 211.8°, 90.0° to 328.2°, and 90.0° to 180.0°, respectively. The rotation directions of the trajectory segments S1, S3, S4, S5, and S7 are respectively: counterclockwise, counterclockwise, clockwise, counterclockwise, and counterclockwise. The parameters of the arc S are shown in Table 1 below.

[0088] Table 1

[0089] Curve number x01μm) y01μm) R(μm) α1(°) α2(°) Direction of rotation S1 9.0 0.0 9.0 180.0 270.0 Counterclockwise S3 60.6 0.0 9.0 270.0 31.8 Counterclockwise S4 92.0 19.5 28.0 211.8 148.2 Clockwise S5 60.6 39.0 9.0 328.2 90.0 Counterclockwise S7 9.0 39.0 9.0 90.0 180.0 Counterclockwise

[0090] At the same time, taking into account the process error, the center coordinates and radius values ​​of each of the above arcs are allowed to be within the range of ±5μm assigned in Table 1, and the starting value α1 and the end value α2 of the value range of the independent variable α are allowed to be within the range of ±5° assigned in Table 1.

[0091] Alternatively, as Figure 3 As shown, in the outer contour of the orthographic projection of the second semiconductor layer 23 on the surface of the first semiconductor layer 21, the trajectory segments S2 and S6 are first straight lines with constant Y-axis coordinates, that is, the first straight lines are parallel to the X-axis.

[0092] The trajectory function of each first straight line is: Y=Y0.

[0093] Where Y0 is a constant, the value of the constant Y0 of the trajectory function of each first straight line, the starting value X1 and the end value X2 of the value range of the independent variable X are shown in Table 2 below.

[0094] Table 2

[0095] Curve number y0(μm) x1(μm) x2(μm) S2 -9 9 60.6 S6 48 60.6 9

[0096] At the same time, taking into account the process error, the values ​​of Y0, the starting value X1, and the end value X2 of each of the first straight lines mentioned above are allowed to be within the range of ±5 μm assigned in Table 2.

[0097] Alternatively, as Figure 3 As shown, in the outer contour of the orthographic projection of the second semiconductor layer 23 on the surface of the first semiconductor layer 21, the trajectory segment S8 is a second straight line with a constant X-axis coordinate, that is, the second straight line is parallel to the Y-axis.

[0098] The trajectory function of each second straight line is: X=X0.

[0099] Where X0 is a constant, the value of the constant X0 of the trajectory function of each second straight line, the starting value Y1 and the end value Y2 of the value range of the independent variable Y are shown in Table 3 below.

[0100] Table 3

[0101] Curve number x0(μm) y1(μm) y2(μm) S8 0 39 0

[0102] At the same time, taking into account the process error, the values ​​of X0, the starting value Y1, and the end value Y2 of each of the second straight lines mentioned above are allowed to be within the range of ±5 μm assigned in Table 3.

[0103] Figure 4 FIG. 4 is a top view of a transparent conductive layer 40 provided in an embodiment of the present disclosure. Figure 4 As shown, the contour line of the orthographic projection of the transparent conductive layer 40 on the surface of the epitaxial layer 20 includes a circular curve and 8 end-to-end track segments, 1≤i≤9.

[0104] like Figure 3 As shown, the contour line M1 is a circular curve, M2, M4, M5, M6 and M8 are arcs, and the remaining trajectory segments are all straight lines.

[0105] In a coordinate system with the first end of the trajectory segment M2 as the origin, the direction parallel to the long side of the epitaxial layer 20 as the X axis, and the direction perpendicular to the long side of the epitaxial layer 20 as the Y axis, the trajectory function of each arc M is:

[0106] X=X0+Rcosα

[0107] Y=Y0+Rsinα

[0108] Where X0 and Y0 are the arc centers, R is the arc radius, and α is the independent variable, representing the angle corresponding to any point in the arc. Each arc is defined by its starting point α1, its ending point α2, and its rotational direction. The parameters for the trajectory segment M are shown in Table 4 below.

[0109] Table 4

[0110] Curve number X01(μm) Y01(μm) R(μm) α1(°) α2(°) Direction of rotation M1 26.00 19.50 13.00 0.00 360.00 Clockwise M2 7.00 0.00 7.00 180.00 270.00 Counterclockwise M4 58.56 0.00 7.00 270.00 31.85 Counterclockwise M5 90.00 19.50 30.00 211.80 148.20 Clockwise M6 58.56 39.00 7.00 328.15 90.00 Counterclockwise M8 7.00 39.00 7.00 90.00 180.00 Counterclockwise

[0111] At the same time, taking into account the process error, the center coordinates and radius values ​​of each of the above arcs are allowed to be within the range of ±5μm assigned in Table 4, and the starting value α1 and the end value α2 of the value range of the independent variable α are allowed to be within the range of ±5° assigned in Table 4.

[0112] Alternatively, as Figure 4 As shown, in the outline of the orthographic projection of the transparent conductive layer 40 on the surface of the epitaxial layer 20, the track segments M3 and M7 are first straight lines with constant Y-axis coordinates, that is, the first straight lines are parallel to the X-axis.

[0113] The trajectory function of each first straight line M is: Y=Y0.

[0114] Where Y0 is a constant, the value of the constant Y0 of the trajectory function of each first straight line, the starting value X1 and the end value X2 of the value range of the independent variable X are shown in Table 5 below.

[0115] Table 5

[0116] Curve number y0(μm) x1(μm) x2(μm) M3 -7 7 58.56 M7 46 58.56 7

[0117] At the same time, taking into account the process error, the values ​​of Y0, the starting value X1, and the end value X2 of each of the first straight lines mentioned above are allowed to be within the range of ±5μm assigned in Table 5.

[0118] Alternatively, as Figure 4 As shown, in the outline of the orthographic projection of the transparent conductive layer 40 on the surface of the epitaxial layer 20, the trajectory segment M9 is a second straight line with a constant X-axis coordinate, that is, the second straight line is parallel to the Y-axis and the first side.

[0119] The trajectory function of each second straight line is: X=X0.

[0120] Where X0 is a constant, the value of the constant X0 of the trajectory function of each second straight line, and the starting value Y1 and the end value Y2 of the value range of the independent variable Y are shown in Table 6 below.

[0121] Table 6

[0122] Curve number x0(μm) y1(μm) y2(μm) M9 0 39 0

[0123] At the same time, taking into account the process error, the values ​​of X0, the starting value Y1, and the end value Y2 of each of the above-mentioned second straight lines can be allowed to be within the range of ±5μm assigned in Table 6.

[0124] The test data of the light emitting diode provided by the embodiment of the present disclosure is as follows Figure 5 As shown in the figure, the forward voltage of the light-emitting diode provided by the embodiment of the present disclosure (experimental group) is about 0.012V lower than the forward voltage of the base group. This shows that the light-emitting diode provided by the embodiment of the present disclosure can increase the center-to-center distance between the two electrodes, prevent the solder balls in the package bonding link from colliding with each other, and still maintain a nearly constant forward voltage of the light-emitting diode.

[0125] Figure 6 This is a flow chart of a method for preparing a light emitting diode provided by an embodiment of the present disclosure. Figure 6 As shown, the preparation method comprises:

[0126] Step 101: Prepare an epitaxial layer.

[0127] Wherein, the epitaxial layer is prepared on the substrate.

[0128] For example, the epitaxial layer may include a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on a substrate, wherein the first semiconductor layer has a first conductivity type, the second semiconductor layer has a second conductivity type different from the first conductivity type, and the active layer is configured to generate light through electron-hole recombination.

[0129] One of the first semiconductor layer and the second semiconductor layer is a p-type layer, and the other of the first semiconductor layer and the second semiconductor layer is an n-type layer.

[0130] As an example, the first semiconductor layer is an n-type layer, and the second semiconductor layer is a p-type layer.

[0131] The epitaxial layer includes a light-emitting area and a non-light-emitting area, and the second semiconductor layer of the epitaxial layer has a groove exposing the first semiconductor layer. The first semiconductor layer exposed by the groove is the non-light-emitting area, and the second semiconductor layer is the light-emitting area.

[0132] The epitaxial wafer fabrication in step 101 may include the following steps:

[0133] In the first step, a first semiconductor layer, an active layer and a second semiconductor layer are grown on a substrate in sequence.

[0134] For example, the substrate may be a sapphire substrate. Since the sapphire substrate has a relatively high light transmittance, is relatively hard, and has relatively stable chemical properties, the use of a sapphire substrate can enable the light-emitting diode to have good light-emitting effect and stability.

[0135] Optionally, the first semiconductor layer is a silicon-doped n-type GaN layer, and the thickness of the n-type GaN layer may be 0.5 μm to 3 μm.

[0136] Optionally, the active layer includes alternately grown InGaN quantum well layers and GaN quantum barrier layers, wherein the active layer may include 3 to 8 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0137] As an example, in the embodiment of the present disclosure, the active layer includes five periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0138] Optionally, the thickness of the active layer may be 150 nm to 200 nm.

[0139] Optionally, the second semiconductor layer is a magnesium-doped p-type GaN layer, and the thickness of the p-type GaN layer may be 0.5 μm to 3 μm.

[0140] In the second step, the surface of the second semiconductor layer is etched to form a groove exposing the first semiconductor layer.

[0141] In the third step, the epitaxial layer is etched to expose the substrate.

[0142] Step 102: forming a transparent conductive layer in the light emitting area.

[0143] Illustratively, the transparent conductive layer may be an ITO layer or an IZO layer.

[0144] Specifically, the process may include: projecting the pattern on the mask onto the photoresist through photolithography, and removing the exposed ITO through wet etching. Projecting the pattern on the mask onto the photoresist through photolithography, and removing the exposed ITO through wet etching.

[0145] Step 103: forming a first electrode and a second electrode.

[0146] The first electrode is located in the non-luminous area, the second electrode is located on the surface of the transparent conductive layer away from the epitaxial layer, and the ratio of the minimum distance from the peripheral edge of the transparent conductive layer to the peripheral edge of the luminous area to the shortest distance between the first electrode and the second electrode is 0.06 to 0.08.

[0147] For example, Figure 2As shown, the prepared first electrode is located in the groove, and the prepared second electrode is located on the surface of the transparent conductive layer.

[0148] The specific steps may include the following:

[0149] In the first step, a passivation layer is formed on the surface of the epitaxial layer and the surface of the transparent conductive layer.

[0150] Optionally, the passivation layer includes a silicon oxide layer.

[0151] When preparing the passivation layer, the deposition temperature is controlled to be between 150°C and 250°C, and the deposition rate is between 15 angstroms per second and 25 angstroms per second. The passivation layer produced using this process can relieve stress and improve the quality of light-emitting diodes.

[0152] Exemplarily, the deposition temperature of the passivation layer is 200° C., and the deposition rate of the passivation layer is 20 Å / s.

[0153] In the second step, through holes are made on the passivation layer to expose the transparent conductive layer and the first semiconductor layer respectively.

[0154] Specifically, the method may include: forming a photoresist layer on the surface of the passivation layer, opening a hole in the photoresist layer in a region corresponding to the through hole, and then etching the passivation layer with a buffered oxide etching solution.

[0155] The buffered oxide etching solution is a mixture of hydrofluoric acid and water, or a mixture of ammonium fluoride and water.

[0156] In the third step, after forming the through hole, a first electrode and a second electrode are fabricated on the surface of the passivation layer.

[0157] Finally, the sapphire can be invisible cut and scratched, which can effectively reduce the loss of brightness. Then, the light-emitting diode is tested.

[0158] The above description is merely an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A light emitting diode, characterized in that: The light-emitting diode comprises: an epitaxial layer (20), a transparent conductive layer (40), a first electrode (31) and a second electrode (32); the epitaxial layer (20) comprises a light-emitting region (201) and a non-light-emitting region (202); The ratio of the minimum distance from the peripheral edge of the transparent conductive layer (40) to the peripheral edge of the light-emitting area (201) to the shortest distance between the first electrode (31) and the second electrode (32) is 0.06 to 0.

08.

2. The light emitting diode according to claim 1, characterized in that The ratio of the shortest distance between the first electrode (31) and the second electrode (32) to the length of the long side of the epitaxial layer (20) is 0.2 to 0.

25.

3. The light emitting diode according to claim 1, characterized in that The ratio of the shortest distance from the first electrode (31) to the light-emitting area (201) to the shortest distance between the first electrode (31) and the second electrode (32) is 0.3 to 0.

45.

4. A light emitting diode, characterized in that: The light-emitting diode comprises: an epitaxial layer (20), a first electrode (31) and a second electrode (32); the epitaxial layer (20) comprises a light-emitting region (201) and a non-light-emitting region (202); The orthographic projection of the side of the light-emitting area (201) close to the first electrode (31) on the epitaxial layer (20) includes a first arc segment (2011), a second arc segment (2012) and a third arc segment (2013) connected in sequence, wherein the first arc segment (2011) and the third arc segment (2013) are both bent in the direction of the first electrode (31), and the second arc segment (2012) is bent in the direction away from the first electrode (31).

5. The light emitting diode according to claim 4, characterized in that The first arc segment (2011) and the third arc segment (2013) have the same radius; The ratio of the radius of the first arc segment (2011) to the length of the short side of the epitaxial layer (20) is 0.1 to 0.

16.

6. The light emitting diode according to claim 4, characterized in that The ratio of the radius of the second arc segment (2012) to the length of the short side of the epitaxial layer (20) is 0.34 to 0.

46.

7. A light emitting diode, characterized in that: The light-emitting diode comprises: an epitaxial layer (20), wherein the epitaxial layer (20) comprises a light-emitting region (201) and a non-light-emitting region (202); The orthographic projection of the light-emitting area (201) on the epitaxial layer (20) is proportionally magnified by 0.9 to 1.1 times and is located within a closed curve, wherein the closed curve includes 8 end-to-end track segments Si, 1≤i≤8; Among them, the trajectory segments S1, S3, S4, S5 and S7 are arcs, and the trajectory segments S2, S6 and S8 are straight lines.

8. The light emitting diode according to claim 7, characterized in that In a coordinate system with the first end of the trajectory segment S1 as the origin, the direction parallel to the long side of the light emitting diode as the X axis, and the direction perpendicular to the long side of the light emitting diode as the Y axis; The functions of trajectory segments S1, S3, S4, S5, and S7 are: X=X0+Rcosα Y=Y0+Rsinα Where X0 and Y0 are the centers of the arc, R is the radius of the arc, and α is the angle corresponding to any point in the arc; The values ​​of R of the trajectory segments S1, S3, S4, S5, and S7 are 9.0 μm, 9.0 μm, 28.0 μm, 9.0 μm, and 9.0 μm, respectively.

9. The light emitting diode according to claim 8, characterized in that The value ranges of α for trajectory segments S1, S3, S4, S5, and S7 are: 180.0° to 270.0°, 31.8° to 270.0°, 148.2° to 211.8°, 90.0° to 328.2°, and 90.0° to 180.0°, respectively.

10. The light emitting diode according to claim 9, characterized in that The rotation directions of the trajectory segments S1, S3, S4, S5 and S7 are respectively: counterclockwise, counterclockwise, clockwise, counterclockwise and counterclockwise.

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