KR102528843B1 - Light emitting element and light emitting device using the same - Google Patents

Abstract

An object of the present invention is to provide a light emitting element capable of eliminating bias in luminance distribution and obtaining uniform light emission, and a light emitting device using the same.
According to the present invention, as a light emitting element having a hexagonal planar shape, an n-side semiconductor layer 2n, a p-side semiconductor layer 3p provided on the n-side semiconductor layer 2n, and a p-side semiconductor layer ( 3p), provided in regions other than the three corner portions R2, R4, and R6 located at opposite angles to each other, and a plurality of holes 6 exposing the n-side semiconductor layer 2n, and the p-side semiconductor layer 3p ), the first p-electrode 4p installed in contact with the first p-electrode 4p, the second p-electrode 5n provided at each of the three corners R1, R3, and R5 on the first p-electrode 4p, and the first p-electrode 4p. ), and provided with an n-electrode 7n electrically connected to the n-side semiconductor layer 2n through a plurality of holes 6.

Description

Light emitting element and light emitting device using the same {LIGHT EMITTING ELEMENT AND LIGHT EMITTING DEVICE USING THE SAME}

The present invention relates to a light emitting element and a light emitting device using the same.

[0003] Conventionally, various researches have been conducted on a light emitting element for obtaining uniform light emission with good light extraction efficiency (for example, see Patent Literatures 1 to 3, etc.).

Japanese Unexamined Patent Publication No. 2010-251481 Japanese Unexamined Patent Publication No. 2006-203058 Japanese Unexamined Patent Publication No. 2008-524831

An embodiment of the present invention is to provide a light emitting element and a light emitting device using the light emitting element capable of further improving light extraction from the upper surface by minimizing light emission from each part of the light emitting element and its periphery. The purpose.

The light emitting element according to the embodiment of the present invention,

(1) A light emitting element having a hexagonal planar shape,

an n-side semiconductor layer;

a p-side semiconductor layer provided on the n-side semiconductor layer;

A plurality of holes provided in a region of the p-side semiconductor layer excluding three corner portions located at opposite angles to each other when viewed from a plan view, and exposing the n-side semiconductor layer;

a first p-electrode provided in contact with the p-side semiconductor layer;

a second p-electrode provided on each of the three respective portions on the first p-electrode;

and an n-electrode installed on the first p-electrode and electrically connected to the n-side semiconductor layer through the plurality of holes.

(2) A light emitting element having a hexagonal planar shape,

an n-side semiconductor layer;

a p-side semiconductor layer provided on the n-side semiconductor layer;

A plurality of holes provided in a region of the p-side semiconductor layer excluding two corner portions located farthest away from each other and exposing the n-side semiconductor layer when viewed from a plan view;

a first p-electrode provided in contact with the p-side semiconductor layer;

a second p-electrode provided on each of the three respective portions on the first p-electrode;

and an n-electrode installed on the first p-electrode and electrically connected to the n-side semiconductor layer through the plurality of holes.

A light emitting device according to an embodiment of the present invention,

(3) the light emitting element;

A body on which the light emitting element is installed;

A hemispherical light transmitting member covering the light emitting element is provided.

According to the embodiment of the present invention, it is possible to realize a light emitting element and a light emitting device using the light emitting element capable of further improving light extraction from the upper surface by minimizing light emission from each portion of the light emitting element and its peripheral portion.

1A is a schematic plan view schematically showing the configuration of a light emitting element according to an embodiment of the present invention.
Fig. 1B is an enlarged plan view of a main part of the light emitting element in Fig. 1A.
Fig. 1C is a cross-sectional view taken along line A-A' in Fig. 1A.
Fig. 1D is a cross-sectional view taken along line BB' in Fig. 1A.
Fig. 1E is a schematic plan view schematically showing a partial configuration of a light emitting device according to an embodiment of the present invention including the light emitting element shown in Fig. 1A.
Fig. 1F is a cross-sectional view taken along line AA' in Fig. 1E.
Fig. 2 is a schematic plan view schematically showing the configuration of a light emitting element according to another embodiment of the present invention.
Fig. 3 is a schematic plan view schematically showing the configuration of a light emitting element according to still another embodiment of the present invention.
Fig. 4A is a schematic plan view schematically showing the configuration of a light emitting element according to still another embodiment of the present invention.
Fig. 4B is an enlarged plan view of a main part of the light emitting element in Fig. 4A.
Fig. 4C is a cross-sectional view taken along line A-A' in Fig. 4A.
5 is a diagram showing simulation results of the current density distribution of the light emitting element according to the embodiment of the present invention.
6A and 6B are diagrams showing simulation results of the current density distribution of the light emitting element for reference.
7A to 7F are schematic plan views for explaining the position of the second p-electrode in the light emitting element according to the embodiment of the present invention.
8A is a plan view schematically showing the configuration of a light emitting device using a light emitting element according to an embodiment of the present invention.
Fig. 8B is a cross-sectional view taken along line A-A' in Fig. 8A.
9A is a plan view schematically showing the configuration of another light emitting device using a light emitting element according to an embodiment of the present invention.
Fig. 9B is a cross-sectional view taken along line A-A' in Fig. 9A.
Fig. 10A is a plan view schematically showing the configuration of a light source unit using the light emitting device of Fig. 9A according to an embodiment of the present invention.
Fig. 10B is a cross-sectional view taken along line A-A' in Fig. 10A.
Fig. 11A is a plan view schematically showing the configuration of another light source unit using the light emitting device of Fig. 9A according to an embodiment of the present invention.
Fig. 11B is a cross-sectional view taken along line A-A' in Fig. 11A.

In the following description, terms indicating a specific direction or position (eg, "up", "down", "right", "left" and other terms including these terms) are used as necessary. The use of these terms is to facilitate understanding of the invention referring to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. The same reference numerals shown in a plurality of drawings denote the same parts or members. In order to make the invention easy to understand, a plurality of embodiments are described, but these embodiments are not independent of each other, and descriptions of other embodiments are applied where they can be shared.

Embodiment 1: Light-emitting element

As shown in FIG. 1A, the light emitting element 10 of this embodiment has a hexagonal planar shape. As shown in FIGS. 1A and 1B , the light emitting element 10 includes an n-side semiconductor layer 2n, a p-side semiconductor layer 3p provided on the n-side semiconductor layer 2n, and a p-side semiconductor layer 3p. ), a plurality of holes 6 provided at specific positions, a first p-electrode 4p provided in contact with the p-side semiconductor layer 3p, and a plurality of holes 6 on the first p-electrode 4p The second p-electrode 5p provided on each of the undisposed corners R1, R3 and R5, and the n-electrode 7n electrically connected to the n-side semiconductor layer 2n via a plurality of holes 6, provide The plurality of holes 6 are three corners of the p-side semiconductor layer at opposite angles to each other in plan view, for example, regions excluding R1, R3, and R5 in FIG. 1A (in other words, FIG. 1A , it is provided in the regions adjacent to the respective portions R2, R4, and R6, the respective sides, and the regions inner than these).

In the light emitting element 10, the second p-electrode 5p connected to the outside is disposed over the regions of three corner portions located at opposite angles to each other in the p-side semiconductor layer 3p. On the other hand, a plurality of holes 6 are provided in regions other than the three corner portions R1, R3, and R5 where the second p-electrode is disposed, and an n-electrode 7n passes through the plurality of holes 6 to n It is electrically connected to the side semiconductor layer 2n. As a result, of the current supplied to the semiconductor layer, the current supplied to the corner portions R1, R3, and R5 where the second p-electrode 5p is disposed is suppressed, while the region other than these corner portions, that is, the plurality of holes ( 6) can increase the current supplied to the region adjacent to the side of the p-side semiconductor layer where 6) is disposed and to the region inside the corner portions R1, R3 and R5. As a result, light emission from the respective portions R1, R3, and R5 of the light emitting element 10 and the region around them is minimized, and the upper surface of the other light emitting element 10 (particularly, the respective portions R1, R3, Light extraction from the inner region surrounded by R5) can be further improved.

The planar shape of the light emitting element 10 is preferably a regular hexagon, but variations in the angles of the six corners by about 120 degrees ± 5 degrees are acceptable. Each side constituting the hexagon is usually a straight line, but may be slightly curved or bent depending on the processing accuracy of the semiconductor layer. Accordingly, the planar shape of the light emitting element includes a regular hexagon and a shape similar thereto, taking this into consideration.

Such a light emitting element having a hexagonal planar shape may have a length of about 300 to 2000 μm on one side, for example. In other words, the length of the diagonal connecting the corner part at the farthest position may be about 600 to 4000 μm. In other words, the plane area of the light emitting element is about 0.2 to 10 mm 2 .

(semiconductor layer)

The semiconductor layer includes at least an n-side semiconductor layer 2n and a p-side semiconductor layer 3p. In addition, it is preferable to include an active layer between them. The planar shape of the n-side semiconductor layer 2n and/or the p-side semiconductor layer 3p is preferably a hexagon in order to make the planar shape of the light emitting element hexagonal. However, in the n-side semiconductor layer 2n and/or the p-side semiconductor layer 3p, there may be a portion removed in part or all in the film thickness direction on a part of the outer periphery and/or on the inner side. In addition, based on the light emitting region (the active layer corresponds to this in this embodiment), the semiconductor on the side to which the n electrode is connected is the n-side semiconductor layer 2n, and the semiconductor on the side to which the p electrode is connected is the p-side semiconductor layer 3p.

As these n-side semiconductor layers, active layers, and p-side semiconductor layers, for example, nitride semiconductors represented by In _X Al _Y Ga _{1 -XY} N (0≤≤X, 0≤≤Y, X+Y<1) can be used. . For the film thickness and layer structure of each layer constituting the semiconductor layer, those known in the relevant field can be used.

The semiconductor layer is formed on the substrate for semiconductor growth. In the case of using a nitride semiconductor for the semiconductor layer, a substrate made of sapphire (Al ₂ O ₃ ) can be used.

(hole)

The plurality of holes 6 are provided in a region of the p-side semiconductor layer excluding three corner portions located at opposite angles to each other in a plan view, and expose the n-side semiconductor layer.

Here, the corner parts located at opposite angles to each other mean that they are not adjacent to each other and are located facing each other. Note that, in the case of a p-side semiconductor layer having a hexagonal planar shape, the three corner portions located at opposite angles to each other refer to every other three corner portions.

The hole 6 may be formed in any region of the p-side semiconductor layer, as long as it is provided in a region excluding the three corner portions located at opposite angles to each other. In other words, if it is not formed only on every three corner parts, it is not necessary to form it on four corner parts including every other three corner parts, and it is formed on five corner parts including every other three corner parts. It may not exist, and it may not be formed in all leg parts. In any of these cases, it is preferable that holes are provided in regions of the p-side semiconductor layer other than the corner portions, particularly in the inner region surrounded by at least three corner portions, and light emitted from the upper surface of the light emitting element can be increased. .

For example, in the light emitting element A shown in FIG. 7A, the hole 6 is formed in three corner portions represented by R2, R4, and R6, which are every other three corner portions, and are diagonal to each other. It is not formed in the three corners indicated by R1, R3 and R5 at the position. In the light emitting element B shown in B of FIG. 7 , the hole 6 is not formed in the corner part indicated by R2 in addition to the three corner parts indicated by R1, R3 and R5 located opposite to each other, and is not formed in the corner part indicated by R4 and R4. It is formed in the two corner parts represented by R6. In the light emitting element C shown in Fig. 7C, the hole 6 is not formed in the corner portions indicated by R1, R3, R4, and R6, which are located at opposite angles to each other, but in the two corner portions indicated by R2 and R5. is formed In the light emitting element D shown in D of FIG. 7 , the hole 6 is formed in one corner portion indicated by R6, but in addition to the three corner portions indicated by R1, R3 and R5 located opposite to each other, It is not formed in the two corner parts indicated by R2 and R4. However, here, any of R1 to R6 may be sufficient as the corner part in which the hole 6 is formed. Further, in the light emitting element E shown in FIG. 7E , the hole 6 is not formed in any of the corner portions including the three corner portions indicated by R1, R3 and R5 which are located at opposite angles to each other.

In the specification of the present application, the term "cornered portion" means, as described above, two lines constituting the outer edges of the light emitting element and/or the n-side semiconductor layer and/or the p-side semiconductor layer intersect at 120 degrees ± 5 degrees when viewed in a plan view. and refers to a fan-shaped region (see 7ni in FIG. 1B) formed by making the two lines two sides. However, it may be a region (refer to 27n in Fig. 2 and 47ni in Fig. 4b) including a portion extending slightly inward as long as the fan-shaped region is included. The two lines are preferably about 1/3 or less of the length of the sides forming the hexagon, and more preferably about 1/4 or less.

As described above, the hole 6 is a hole through which the n-side semiconductor layer is exposed. A plurality of n-side semiconductor layers exposed by the hole can be used to electrically connect integrally with the n-side semiconductor layer through an n-electrode described later.

The number, size, shape, and position of the holes can be appropriately set according to the intended size, shape, connection state, and the like of the light emitting element.

It is more preferable that all the holes are arranged in the same size and shape. In this way, it is possible to realize uniformity of the supply amount of current. As a result, the luminous intensity of the entire light emitting element can be made uniform, and unevenness in luminance can be suppressed.

As for the shape of a hole, polygons, such as a circle, an ellipse, a triangle, a rectangle, and a hexagon, etc. are mentioned in planar view, and a circular shape or an ellipse is especially preferable. The size of the hole can be appropriately adjusted according to the size of the semiconductor layer, required output of the light emitting element, luminance, and the like. The hole preferably has, for example, a diameter (one side) of about several tens to several hundred micrometers. From another point of view, the diameter is preferably about 1/20 to 1/5 of one side of the semiconductor layer. From another point of view, it can be appropriately adjusted according to the total plane area occupied by the hole, for example. Specifically, the total plane area is about 1/100 to 1/20 of the plane area of the light emitting element described above. In other words, about 2000 μm ² to 0.5 mm 2 can be cited. The number of holes is, for example, about 2 to 100, preferably about 4 to 80.

It is preferable that a plurality of holes are arranged side by side along the side of the p-side semiconductor layer in plan view, as shown in Fig. 1A, for example. In this case, it is more preferable to arrange adjacent holes at equal intervals. However, between some of the holes, the intervals may be different. Here, the equal interval means not only that the holes are all arranged at equal intervals, but also that such intervals allow a difference within a range of about ±5%. The shortest distance between holes (hereinafter, distance between centers of holes) is, for example, about 2 to 8 times the size (eg, diameter) of the hole, and a distance of about 4 to 6 times is preferable. do. Specifically, when the p-side semiconductor layer has a hole with a diameter of about 50 μm, the shortest distance is about 100 to 400 μm, preferably about 200 to 300 μm.

By arranging these holes, it is possible to control the current injected into the n-side semiconductor layer and improve the luminous efficiency.

(1st p-electrode, 2nd p-electrode and n-electrode)

The light emitting element includes at least a first p-electrode (4), a second p-electrode (5), and an n-electrode (7).

These electrodes may be formed of, for example, metals such as Ag, Au, Pt, Pd, Rh, Ni, W, Mo, Cr, Ti, Al, and Cu, or alloys thereof, or, for example, Zn , In, Sn, Ga, and Mg. Examples of the translucent conductive film include ITO, ZnO, IZO, GZO, In ₂ O ₃ and SnO ₂ . etc. can be mentioned.

The first p-electrode 4 is provided on the p-side semiconductor layer and in contact with the p-side semiconductor layer. The first p-electrode is an ohmic electrode layer, but can also function as a light reflection electrode layer, for example. Therefore, the larger the contact area with the p-side semiconductor layer, the more preferable the first p-electrode is. , It is more preferable that it is formed on the substantially entire surface including the above-mentioned corner part.

As the light reflection electrode layer, it can be formed of a layer (Ag-containing layer) containing Ag or an Ag alloy or the like. The layer made of Ag or Ag alloy is preferably disposed in contact with the semiconductor layer or at a position closest to the semiconductor layer. As the Ag alloy, any of materials known in the field may be used. The thickness of the light reflection electrode layer is not particularly limited, and a thickness capable of effectively reflecting light emitted from the semiconductor layer, for example, is about 20 nm to 1 μm. In order to prevent migration of Ag, it is preferable to provide an additional conductive layer or insulating layer covering the upper surface (preferably, the upper surface and side surface) thereof.

Such an additional conductive layer can be formed by a single-layer film or a laminated film made of the metals listed as the above-mentioned electrode materials or alloys thereof. For example, a monolayer film containing at least a metal such as Al, Cu or Ni, or a laminated film such as Ni/Ti/Ru or Ni/Ti/Pt may be used. In addition, the thickness of the conductive layer may be on the order of several hundred nanometers to several micrometers in order to effectively prevent migration of Ag.

In addition, the additional insulating layer is, for example, partially opened on the upper surface of the light reflective electrode layer, and an insulating layer such as SiN or SiO ₂ is formed so as to cover the side surface of the light reflective electrode layer, thereby preventing Ag migration. can do. Further, the insulating layer may be either a single layer film or a multilayer film.

As the ohmic electrode layer, a single-layer film or a laminated film made of the light-transmitting conductive film described above can be used.

The second p-electrode is on the first p-electrode and is disposed at the corner in a plan view. However, the second p-electrode is not disposed in the region where the hole is disposed. As described above, the second p-electrode is disposed on three corner portions at opposite angles to each other, where no hole is disposed. However, the second p-electrode may be further disposed at a corner portion in which no hole is disposed, as long as the second p-electrode is disposed at the three corner portions at opposite angles to each other.

That is, it is preferable that the second p-electrode is disposed on three or more corner portions among the six corner portions of the light emitting element. When the second p-electrode is disposed on three corner portions, as shown in Fig. 7A, it is preferable to arrange three corner portions that are not adjacent to each other, in other words, three corner portions located at opposite angles to each other. In the case where the second p-electrode is disposed on four corner portions, as shown in Fig. 7B, it is preferable that the second p-electrode be disposed on any one corner portion in addition to the three angle portions located opposite each other. When the second p-electrode is disposed in five or six corner portions, as shown in FIG. 7D and FIG. 7E, it may be disposed in any corner portion, and the two corner portions in which the second p-electrode is not disposed. It is preferable to arrange so that are not adjacent to each other (see FIG. 7B and FIG. 7C). Among them, it is more preferable that the second p-electrode is disposed on three corner parts or six corner parts that are not adjacent to each other, which has excellent uniformity of current density distribution. This is preferable because the extraction of light from the region of can be further improved.

The 2nd p-electrode, for example, when viewed from a plane, has a corner portion, that is, a fan shape formed by two lines crossing at 120 degrees ± 5 degrees and two sides of the two lines, a shape similar thereto, or these It is preferable to have a shape including a shape (hereinafter sometimes referred to as "a fan shape"). It is exemplified that the two lines have a length of 40% or less of the sides forming the hexagon, preferably about 35% or less, about 30% or less, about 25% or less, about 20% or less, or about 15% or less. In other words, shapes such as a sector having one side of about 30 to 300 μm or one side of about 100 to 300 μm are exemplified.

The n-electrode is provided on the first p-electrode. The n-electrode is not provided on the second p-electrode, but is disposed spaced apart from the second p-electrode in a plan view. Also, the n-electrode is electrically connected to the n-side semiconductor layer through the plurality of holes described above. The n-electrode may be divided into a plurality of n-electrodes, but one n-electrode is preferably connected to the n-side semiconductor layer through a plurality of holes so that the connection area at the time of mounting can be widened and current can be uniformly supplied.

The second p-electrode and/or n-electrode is, specifically, Ti/Rh/Au, Ti/Pt/Au, W/Pt/Au, Rh/Pt/Au, Ni/Pt/Au, Al from the semiconductor layer side. -Cu alloy/Ti/Pt/Au, Al-Si-Cu alloy/Ti/Pt/Au, Ti/Rh, Ti/Rh/Ti/Pt/Au, Ag/Ni/Ti/Pt, Ti/ASC/Ti /Rt/Au (here, ASC is an Al/Si/Cu alloy) or the like. In addition, the light-transmitting conductive film described above may be disposed on the semiconductor layer side of such a laminated structure.

The n-electrode is disposed in a region extending from a part of the exposed surface of the n-side semiconductor layer, which is the bottom surface of the hole provided in the above-mentioned p-side semiconductor layer, to the side surface of the hole (side surface of the active layer and the p-side semiconductor layer) and above the p-side semiconductor layer. It is preferable to extend over the p-side semiconductor layer from the inside of the hole via the formed insulating film. As the insulating film here, it is preferable to use a known material film in the field, a single-layer film or a laminated film, with a thickness capable of ensuring electrical insulation.

Part or all of the n-electrode may be slightly smaller than, equal to, or slightly larger than the n-side semiconductor layer in plan view. Further, the n-electrode preferably has an opening corresponding to a fan shape or the like so as to be separated from the second p-electrode in plan view.

Further, a dielectric multilayer film such as a DBR (distributed Bragg reflector) film may be included between the n-electrode and the second p-electrode, and the n-side semiconductor layer and the p-side semiconductor layer, respectively.

Embodiment 2: Light-emitting element

Embodiment 2 has substantially the same configuration as the light emitting element of Embodiment 1, except that the position of the plurality of holes 6 and the position of the second p-electrode in the light emitting element are partially different.

(hole)

In this light emitting element, as shown in FIG. 7F, the plurality of holes are two corner portions located at the furthest position of the p-side semiconductor layer in a plan view, for example, R1 in FIG. 7F and It is provided in the region except for R4 and exposes the n-side semiconductor layer.

Here, the two corner parts at the farthest position mean the corner parts arranged at both ends of the longest diagonal line.

The hole 6 may be formed in any region of the p-side semiconductor layer, as long as it is provided in a region excluding the two corner portions at the farthest position. In other words, as long as it is not formed only on the two corner parts at the farthest position, it is not necessary to be formed on the corner part adjacent to either of these two corner parts, and the five corner parts including the two corner parts at the farthest position It does not have to be formed in, and it is not necessary to be formed in all leg parts. In any of these cases, it is preferable that a hole is provided in a region of the p-side semiconductor layer other than the corner portion, particularly in an inner region sandwiched between at least two corner portions, and the upper surface of the light emitting element (particularly, between the two corner portions). It is possible to increase the light extracted from the area on the inside of the pinched area).

For example, in the light emitting element F shown in F of FIG. 7 , the hole 6 is not formed in the two corner portions indicated by R2 and R5 located at the farthest position, and 4 indicated by R1, R3, R4 and R6. It is formed in each part of the dog. Further, in the light emitting element B shown in B of FIG. 7 , the hole 6 is not formed in the corner parts indicated by R1 and R3 in addition to the two corner parts indicated by R2 and R5 located at the farthest position, and is not formed in the corner parts indicated by R4 and R6. It is formed in the two corner parts represented by . In addition, in the light emitting element C shown in FIG. 7C , the hole 6 is not formed in the corner parts indicated by R1 and R4 in addition to the two corner parts indicated by R3 and R6 located at the farthest position, and is not formed in the corner parts indicated by R2 and R5. It is formed in the two corner parts represented by . In the light emitting element D shown in D of FIG. 7 , the hole 6 is formed in one corner part indicated by R6, but in addition to the four corner parts indicated by R2 and R5 or R1 and R4 located at the farthest position. It is not formed in the corner part represented by R3. However, here, any of R1 to R6 may be sufficient as the corner part in which the hole 6 is formed. In addition, in the light emitting element E shown in FIG. 7E, the hole 6 is not formed in any corner part including the six corner parts indicated by R2 and R5, R1 and R4, or R3 and R6 at the farthest position. .

(2nd p electrode)

The second p-electrode is disposed on the corner portion above the first p-electrode. However, the second p-electrode is not disposed in the region where the hole is disposed. As described above, the second p-electrode is disposed on the two corner portions at the farthest positions where no hole is disposed. However, as long as the second p-electrode is disposed at the two most distant corner portions, it may be further disposed at a corner portion where no hole is disposed.

That is, the second p-electrode is preferably disposed on two or more corner portions among the six corner portions of the light emitting element. In the case where the second p-electrode is disposed on the two corner portions, it is preferable to arrange the two corner portions at the farthest positions, as shown in Fig. 7F. In the case where the second p-electrode is disposed on four corner portions, as shown in FIGS. 7B and 7C , in addition to the two most distant corner portions, the corner portion adjacent to any of these two corner portions It is preferable to arrange at any two corner parts. That is, it is preferable that the second p-electrode is disposed such that the two corner portions on which the second p-electrode is not disposed are not adjacent to each other. In the case where the second p-electrode is disposed in five or six corner portions, it may be disposed in any corner portion, as shown in Figs. 7D and 7E. Among them, it is more preferable that the second p-electrode is disposed at six corner portions.

The light-emitting element of Embodiment 2 having the above configuration minimizes light emission from each corner and its peripheral area in the region where the second p-electrode is disposed, and further improves light extraction from the upper surface of the light-emitting element. can

embodiment 3: light emission Device

As shown in FIGS. 8A and 8B , the light emitting device of one embodiment of the present invention includes the light emitting element 70 described above, a base body 80 on which the light emitting element 70 is installed, and a hemispherical shape covering the light emitting element. A light transmitting member 90 is provided.

Further, in this light-emitting device, a functional member having light reflection, light-transmitting, light-shielding, wavelength converting, etc. is optionally provided on the side surface, upper surface, or lower surface of the light-emitting element or the like (also, the side surface, upper surface, or lower surface of the body). may be placed. For example, a phosphor layer may be formed on the side surface and upper surface of the light emitting element by electrodeposition, spraying, or the like. Further, an optical member (for example, a lens) may be disposed to further cover the light transmitting member 90 .

(gas)

The base material is, for example, metal, ceramic, resin, dielectric, pulp, glass, paper, or a composite material thereof (eg composite resin), or these materials and a conductive material (eg metal, carbon, etc.) A plurality of wiring patterns are optionally provided on the inside and/or back surface of a base material made of a composite material or the like.

The wiring pattern may be any material capable of supplying current to the light emitting element, and is formed of a material, thickness, shape, or the like commonly used in the field. In addition, if the wiring pattern includes a pair of positive and negative patterns connected to the electrodes (second p-electrode and n-electrode) of the light emitting element, it has another pattern arranged independently of the pair of positive and negative patterns. may be

In addition, it is preferable to mount the light emitting element to the base body by, for example, bonding members such as bumps and solder. As the bonding member, any of materials known in the field may be used.

(light-transmitting member)

The light transmitting member covers the light emitting element and also serves as a lens. Therefore, it is preferable to have a hemispherical shape. However, this hemispherical shape does not have to be a strict sphere or a strict half, and may be a partially cut body such as a spherical sphere, an elongated sphere, an egg shape, and a fusiform shape.

The light transmitting member may be formed of glass or the like, but is preferably formed of resin. Examples of the resin include thermosetting resins, thermoplastic resins, modified resins thereof, and hybrid resins containing one or more of these resins.

(absence of functionality)

Examples of functional members include members capable of adding various functions, such as lenses and phosphor layers. One functional member or a plurality of functional members may be disposed with respect to one light emitting element, or one may be disposed with respect to a plurality of light emitting elements.

As a lens, a concave-convex lens, a Fresnel lens, etc. are mentioned, for example. For these lenses, those manufactured by known manufacturing methods using known materials in the field can be used. The lens may contain a light diffusing material or the like. Examples of the light diffusion material include fibrous fillers such as glass fiber and wollastonite, inorganic fillers such as aluminum nitride and carbon, silica, titanium oxide, zirconium oxide, magnesium oxide, glass, crystals or sintered bodies of phosphors, binders of phosphors and inorganic materials, and the like. The sintered body of , etc. are mentioned.

A protective film, a reflective film, an anti-reflection film, or the like may be formed on the light incident surface and/or light exit surface of the lens. As the antireflection film, a 4-layer structure composed of silicon dioxide and zirconium dioxide, etc. can be applied.

As the phosphor, those known in the art can be used. For example, cerium-activated yttrium aluminum garnet (YAG) phosphors, cerium-activated lutetium aluminum garnet (LAG), europium and/or chromium-activated nitrogen-containing aluminum calcium silicate (CaO-Al ₂ O ₃ -SiO ₂ )-based phosphors, europium-activated silicate ((Sr, Ba) ₂ SiO ₄ )-based phosphors, β-SiAlON phosphors, nitride-based phosphors such as CASN-based or SCASN-based phosphors, KSF-based phosphors (K ₂ SiF ₆ :Mn), a sulfide-based phosphor, a so-called nanocrystal, or a light emitting material called a quantum dot may be used. As the light emitting material, semiconductor materials such as group II-VI, group III-V, and group IV-VI semiconductors, specifically, CdSe, core-shell type CdS _x Se _{1 -x} /ZnS, nano nanoparticles such as GaP size of highly dispersed particles. The phosphor can be used singly or in combination of two or more.

With the miniaturization of light-emitting devices in recent years and the miniaturization of the light-transmitting member covering the light-emitting element, as a result of the surface of the light-transmitting member being close to the light-emitting element, the light that passes through the side of the light-emitting device without obtaining a lens effect by the light-transmitting member. This increases, and there is a concern that light taken out from above the light emitting device cannot be obtained with desired efficiency. In contrast, as in the present embodiment, when a light emitting element having a hexagonal planar shape is covered with a light transmitting member, the distance between the light emitting element and the surface of the light transmitting member is reduced compared to a light emitting element having a rectangular planar shape and having the same planar area. more can be obtained. Therefore, the lens effect by the light-transmitting member can be effectively utilized. In addition, the light emitting element according to the present embodiment has a structure for suppressing light emission in the respective portions, in other words, instead of suppressing current supply to the semiconductor layer in the respective portions, current supplied to regions other than the respective portions. has a structure that increases This reduces the light escaping directly from the corner of the light emitting element that tends to approach the surface of the light emitting member to the side of the light emitting device, effectively utilizes the lens effect of the light transmitting member, and efficiently directs the light upward to the light emitting device. can be extracted

Hereinafter, embodiments of a light emitting element and a light emitting device using the same will be described in detail based on the drawings.

Example 1: light emitting element

As shown in Figs. 1A to 1D, the light emitting element 10 of this embodiment has a hexagonal planar shape. This light emitting element 10 includes an n-side semiconductor layer 2n and a p-side semiconductor layer 3p, a first p-electrode 4p, a second p-electrode 5p, and an n-electrode 7n. The length of one side of the light emitting element 10 is about 1.2 mm.

The semiconductor layer is formed by stacking an n-side semiconductor layer 2n, an active layer Ac, and a p-side semiconductor layer 3p in this order on a hexagonal sapphire substrate 8 . The semiconductor layer has a region at its outermost periphery in which the p-side semiconductor layer 3p and a part of the active layer Ac are removed to expose the n-side semiconductor layer 2n.

The p-side semiconductor layer 3p has a plurality of holes 6 . In the hole 6, the active layer Ac existing below it is also removed to expose the n-side semiconductor layer 2n. However, in the p-side semiconductor layer 3p here, holes are not arranged in the three non-adjacent corner portions of the hexagon and their periphery, and a plurality of holes 6 are formed in the region excluding these corner portions and their periphery. has

The hole 6 is substantially circular and has a diameter of about 27 µm, for example, 58 holes are formed. The holes 6 are arranged substantially parallel to the sides of the hexagon in plan view, and the center-to-center distance is about 300 μm. The total area of the hole 6 is about 0.92% of the planar area of the semiconductor layer, and is about 33000 μm ² .

In contact with the p-side semiconductor layer 3p, a first p-electrode 4p is disposed on substantially the entire surface excluding the plurality of holes 6. Here, the approximate entire surface refers to a region other than the outer edge of the upper surface of the p-side semiconductor layer 3p and the inner edge near the hole 6 . For example, it is preferable that the first p-electrode 4p is provided on 90% or more of the upper surface of the p-side semiconductor layer 3p. The first p-electrode 4p comprises an Ag-containing layer formed on substantially the entire surface of the p-side semiconductor layer 3p, a layer covering the upper surface of the Ag-containing layer, and further covering a part of the upper surface and side surfaces of the Ag-containing layer. It has an insulating layer 4a made of SiN. The layer covering the Ag-containing layer is formed by a laminated film of a Ni layer, a Ti layer, and a Pt layer from the semiconductor layer side. With such a laminated structure, light emitted from the active layer Ac can be reflected toward the sapphire substrate 8, so that the light extraction efficiency can be improved. Furthermore, migration of Ag can be effectively prevented by the layer covering the Ag-containing layer and the insulating layer 4a.

On the first p-electrode 4p, the second p-electrode 5p is disposed in a region including three corner portions and their peripheries where the aforementioned holes 6 are not disposed. The second p-electrode 5p has a fan shape having two sides substantially parallel to one of the two sides of the p-side semiconductor layer 3p constituting a region including the provided corner portion and its periphery. The two sides of the fan shape are each about 1/5 of the length of one side of the p-side semiconductor layer 3p, and are about 300 μm.

Above the first p-electrode 4p, an n-electrode 7n electrically connected to the n-side semiconductor layer 2n via a plurality of holes 6 is disposed. In Fig. 1B, the outer circumference of the n-electrode 7n is indicated by 7no and the inner circumference by 7ni. The first p-electrode 4p is disposed over the first p-electrode 4p other than the second p-electrode 5p and its periphery via an insulating film 9 made of SiO ₂ . The insulating film 9 is disposed over the side surface of the hole 6 and a partial region of the exposed n-side semiconductor layer 2n (upper surface of the n-side semiconductor layer 2n). The insulating film 9 is formed on a partial region on the first p-electrode 4p disposed on the p-side semiconductor layer 3p, that is, a connection portion between the first p-electrode 4p and the second p-electrode 5p. , has an opening 9a exposing the upper surface of the first p-electrode 4p. The insulating film 9 also covers the p-side semiconductor layer 3p and the n-side semiconductor layer 2n exposed by removal of a part of the active layer Ac on the outermost periphery of the light emitting element 10 .

Both the second p-electrode 5p and the n-electrode 7n are formed of a laminated film of Ti/Al-Si-Cu alloy/Ti/Pt/Au from the semiconductor layer side.

When manufacturing a light emitting device using such a light emitting element 10, as shown in FIGS. 1E and 1F, bump electrodes BP connected to the second p-electrode 5p are respectively 5p), a plurality of bump electrodes BP connected to the n-electrode 7n are uniformly formed over the entire surface. The bump electrode BP connected to the n-electrode 7n does not overlap with the hole 6 in plan view so that the insulating film 9 is not destroyed by an excessive load when the light emitting element 10 is mounted. It is desirable to form in place.

Example 2: light emitting element

In the light emitting element 20 of Example 2, as shown in FIG. 2, except that the second p-electrode 25p is not a fan shape, but has a shape with two portions extending slightly inward from the fan shape, It has substantially the same configuration as the light emitting element 10 of Example 1.

Example 3: light emitting element

As shown in Fig. 3, in the light emitting element 30 of Example 3, the fan-shaped second p-electrode 5p is disposed in the area including all corner parts and their periphery. Correspondingly, the number of holes 6 is 55, with no holes 6 arranged in the region including the six corners of the p-side semiconductor layer 3p and their peripheries. Therefore, the total area of the hole 6 is about 0.87% of the planar area of the semiconductor layer, and is about 3100 μm ² .

Except for the configuration described above, it has substantially the same configuration as the light emitting element 10 of the first embodiment.

Example 4: light emitting element

As shown in Fig. 4, in the light emitting element 40 of Example 4, a part of the p-side semiconductor layer 3p and the active layer Ac is removed from its outermost periphery to expose the n-side semiconductor layer 2n. It has a region that is covered by the insulating film 9, but has a region that is not covered with the insulating film 9 at each portion. In addition, the second p-electrode 45p having a substantially sector-shaped recessed outer side is disposed in an area including all corner portions and their periphery. Further, in each portion where the second p-electrode 45p is disposed, in a region not covered with the insulating film 9, a part of the n-electrode 7n is in contact with the n-side semiconductor layer 2n for electrical connection. has been

Except for the configuration described above, it has substantially the same configuration as the light emitting element 30 of the third embodiment.

<Evaluation of light emitting element>

Distribution of the current density in the light-emitting elements 10, 20, and 30 of Examples 1 to 3 was analyzed by simulation software using the finite element method. The results are shown in FIGS. 5A to 5C , respectively. 5A to 5C, the darker the shade, the higher the current density.

For reference, as shown in A of FIG. 6 , a light emitting element 40 having substantially the same configuration as the light emitting element 10 except for arranging the second p-electrode 55 along a pair of diagonal lines. ), the current density distribution was also analyzed. The result is shown in FIG. 6B.

5A to 5C, all of the light emitting elements 10, 20, and 30 measure the current density in the region where the second p-electrode 5 is disposed, in the region adjacent to the side of the semiconductor layer and in the region inside. It was found that it can be reduced more than the current density in .

In particular, in the light emitting element 20, by increasing the area of the second p-electrode 25 than that of the light-emitting element 10, the current density in each portion where the second p-electrode 25 is disposed can be reduced. On the other hand, it is possible to improve the current density in the inner region, particularly in the central region of the semiconductor layer.

Further, in the light emitting element 30, as the number of second p-electrodes 35 is increased to six, the current density can be reduced in each portion where the second p-electrodes 35 are disposed. The current density can be improved more uniformly throughout the inner side.

This phenomenon indicates that the current density distribution in the inner region of the semiconductor layer could be increased more remarkably than the current density distribution in the corner and outer periphery of the semiconductor layer in the light emitting element 50 .

In addition, with respect to the light emitting elements 10, 20, and 30, the forward voltage Vf applied with a current of 350 mA was analyzed by simulation using the finite element method. The results are shown in a table together with the number of holes, the total area of the region where the n-electrode is connected to the n-side semiconductor layer via the hole (the area of the n-side contact region), and the area of the first p-electrode (the area of the p-side contact region). shown in 1. In addition, the areas of the n-side contact region and the p-side contact region are relative values of the area of the light emitting element 10 as 100%.

Light emitting element (10) Light-emitting element (20) Light-emitting element (30) Forward voltage Vf (V) 0.344 0.333 0.332 Number of holes (pcs) 58 58 55 Area of n-side contact area (%) 100 100 94.8 Area of p-side contact area (%) 100 100 99.8

As shown in Table 1, it was confirmed that the Vf values of the light emitting elements 20 and 30 were reduced by 0.011V (about 3.1%) and 0.012V (about 3.5%), respectively, relative to the light emitting element 10. In the light-emitting element 20, the area of the p-side contact region is the same as that of the light-emitting element 10, but the area of the second p-electrode is large, and current concentration in the vicinity of the second p-electrode is alleviated, resulting in a reduced Vf value. I think there is. Further, in the light emitting element 30, the number of second p-electrodes is increased from 3 to 6 compared to the light emitting element 10 and the light emitting element 20, so that the current is more evenly supplied to the semiconductor layer, so that the Vf value is higher. I think it is reducing.

Example 5: light emitting device

As shown in FIGS. 8A and 8B , the light emitting device 60 of Example 5 includes a light emitting element 70 having a hexagonal planar shape similarly to the light emitting element 10 of the first embodiment, and a pair of positive and negative surfaces on the surface. A body 80 having a wiring pattern (not shown) is provided.

The light-emitting element 70 is mounted face-down on the base body 80, and the n-electrode and p-electrode of the light-emitting element 70 are connected to the wiring pattern of the base body 80 via a bonding member. Further, the light emitting element 70 is covered with a hemispherical light transmitting member 90 made of silicone resin or the like. The light transmitting member 90 also covers a part of the upper surface of the base body 80 together with the light emitting element 70 .

In such a light-emitting device, the lens effect of the light-transmitting member 90 can be used more effectively to efficiently extract light upward from the light-emitting device.

Example 6: light emitting device

As shown in FIGS. 9A and 9B , the light emitting device 61 of Example 6 includes a light emitting element 70 having a hexagonal planar shape similar to the light emitting element 10 of the first embodiment, and a pair of positive and negative surfaces on the surface. A body 80 having a wiring pattern (not shown) is provided. The light emitting element 70 is mounted face-down on the body 80, and its side surface and upper surface, which is a light extraction surface, are covered with a phosphor layer 92 made of YAG or the like. Further, the surface of the light emitting element 70 covered with the phosphor layer 92 is covered in a substantially rectangular shape with a light transmitting member 91 made of silicone resin or the like.

Such a light emitting device can efficiently take out light of an arbitrary color by utilizing the wavelength conversion effect of the phosphor layer 92 .

Example 7: light source unit

As shown in FIGS. 10A and 10B , the light source unit 65 of the seventh embodiment includes a circuit board 81 and a plurality of light emitting devices 61 of the sixth embodiment mounted on the circuit board 81 at a distance from each other. ) and a lens 93 covering each light emitting device 61. The lens 93 here has a substantially circular shape that can effectively use the light from the light emitting device 61, as shown in FIG. 10A, for example. Further, on the upper surface of the lens 93, which is above the light emitting device 61 and on the opposite side of the lower surface facing the light emitting device 61, as shown in FIG. 10B, the light emitted from the light emitting device 61 is spread. It may have a concave part that can be used.

In such a light source unit, the light emitting devices can be used as a backlight light source or an illumination light source by arranging the light emitting devices vertically and/or horizontally, randomly or regularly.

Example 8: light source unit

As shown in FIGS. 11A and 11B , the light source unit 66 of the eighth embodiment includes a circuit board 81 and a light emitting device 61 of the sixth embodiment mounted on the circuit board 81 spaced apart from each other. , a Fresnel lens 94 covering the light emitting device 61 is provided. The Fresnel lens 94 here has a shape capable of reducing visibility from the outside of, for example, a light emitting element disposed in the light emitting device 61 or a phosphor layer disposed thereon.

Such a light source unit can be used as a flash light for a camera or the like.

Light emitting devices according to the embodiments and examples of the present invention are lighting fixtures, camera flashes, backlight light sources of liquid crystal displays, light sources for various indicators, vehicle-mounted light sources, sensor light sources, signals, vehicle-mounted parts, and signboard channels. It can be used for various light sources such as letters.

10, 20, 30, 40, 50, 70, A, B, C, D, E: light emitting element
2n: n-side semiconductor layer
3p: p-side semiconductor layer
4p: 1st p-electrode
4a: insulating film
5p, 25p, 45p, 5, 15, 25, 35, 45, 55: second p-electrode
6 : hole
7n, 27n, 47n: n electrode
7no, 47no: outer circumference of n electrode
7ni, 47ni: inner circumference of n electrode
8: sapphire substrate
9: insulating film
9a: opening
Ac: active layer
R1, R2, R3, R4, R5, R6: each part
BP: bump
60, 61: light emitting device
65, 66: light source unit
80: gas
81: circuit board
90, 91: light transmitting member
92: phosphor layer
93: lens
94: Fresnel lens

Claims (14)

A light emitting element having a hexagonal planar shape,
an n-side semiconductor layer;
a p-side semiconductor layer provided on the n-side semiconductor layer;
When viewed from a plan view, among the six corner portions of the light emitting element, the p-side semiconductor layer is provided in a region excluding at least three corner portions located at opposite angles to each other, and exposes the n-side semiconductor layer. with a hole in
a first p-electrode provided in contact with the p-side semiconductor layer;
a second p-electrode provided on each of the at least three respective portions on the first p-electrode;
and an n-electrode installed on the first p-electrode and electrically connected to the n-side semiconductor layer through the plurality of holes. A light emitting element having a hexagonal planar shape,
an n-side semiconductor layer;
a p-side semiconductor layer provided on the n-side semiconductor layer;
A plurality of holes provided in a region excluding at least two corner portions located farthest from the p-side semiconductor layer among the six corner portions of the light emitting element when viewed from a plan view, and exposing the n-side semiconductor layer;
a first p-electrode provided in contact with the p-side semiconductor layer;
a second p-electrode provided on each of the at least two corner portions on the first p-electrode;
and an n-electrode installed on the first p-electrode and electrically connected to the n-side semiconductor layer through the plurality of holes. According to claim 1 or 2,
The plurality of holes are not provided in the six corner portions. According to claim 3,
The light emitting element wherein the second p-electrode is provided on each of the six corner portions on the first p-electrode. According to claim 1 or 2,
The second p-electrode is a fan shape having two sides parallel to one of the two sides constituting the corner portion provided respectively. According to claim 1 or 2,
The plurality of holes are arranged along the sides of the p-side semiconductor layer. According to claim 1 or 2,
The n-electrode is provided over the first p-electrode from a portion electrically connected to the n-side semiconductor layer through an insulating layer. According to claim 7,
The insulating layer is a dielectric multilayer film, a light emitting element. According to claim 1 or 2,
The first p-electrode includes a silver (Ag)-containing layer in contact with the p-side semiconductor layer. According to claim 1 or 2,
The first p-electrode is a light-transmitting conductive film. According to claim 1 or 2,
The n-electrode is electrically connected to the n-side semiconductor layer via a translucent conductive film in contact with the n-side semiconductor layer, respectively, in the plurality of holes. As a light emitting device,
The light emitting device according to claim 1 or 2,
A body on which the light emitting element is installed;
A light-emitting device comprising a hemispherical light-transmitting member covering the light-emitting element. According to claim 12,
The light-emitting device further comprising a phosphor layer between the light-emitting element and the light-transmitting member. According to claim 12,
A light emitting device further comprising an optical member covering the light transmitting member.

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