KR102551894B1 - Semiconductor device - Google Patents

Abstract

An embodiment includes a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, wherein the second conductivity type semiconductor layer a light emitting structure including a plurality of first recesses extending through the active layer to a partial region of the first conductive type semiconductor layer and a second recess disposed between the plurality of first recesses; a plurality of first electrodes disposed inside the plurality of first recesses and electrically connected to the first conductive semiconductor layer; and a reflective layer disposed inside the second recess, wherein the plurality of first recesses and second recesses extend in a first direction, the first direction being a direction perpendicular to a thickness direction of the light emitting structure. A semiconductor device is disclosed.

Description

Semiconductor device {SEMICONDUCTOR DEVICE}

The embodiment relates to a semiconductor device.

Semiconductor devices including compounds such as GaN and AlGaN have many advantages, such as having a wide and easily adjustable band gap energy, and can be used in various ways such as light emitting devices, light receiving devices, and various diodes.

In particular, light emitting devices such as light emitting diodes or laser diodes using group 3-5 or group 2-6 compound semiconductor materials of semiconductors are developed in thin film growth technology and device materials to produce red, green, Various colors such as blue and ultraviolet can be realized, and white light with high efficiency can be realized by using fluorescent materials or combining colors. , safety, and environmental friendliness.

In addition, when light receiving devices such as photodetectors or solar cells are manufactured using group 3-5 or group 2-6 compound semiconductor materials, photocurrent is generated by absorbing light in various wavelength ranges through the development of device materials. By doing so, it is possible to use light in a wide range of wavelengths from gamma rays to radio wavelengths. In addition, it has the advantages of fast response speed, safety, environmental friendliness, and easy control of element materials, so that it can be easily used in power control or ultra-high frequency circuits or communication modules.

Accordingly, the semiconductor device can replace a transmission module of an optical communication means, a light emitting diode backlight that replaces a Cold Cathode Fluorescence Lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, and can replace a fluorescent lamp or an incandescent bulb. Applications are expanding to white light emitting diode lighting devices, automobile headlights and traffic lights, and sensors that detect gas or fire. In addition, applications of semiconductor devices can be expanded to high-frequency application circuits, other power control devices, and communication modules.

In particular, a light emitting element that emits light in the ultraviolet wavelength region can be used for curing, medical, and sterilization purposes by performing a curing or sterilizing action.

In a conventional semiconductor device, light generated in an active layer may travel in a lateral or downward direction in addition to an upper direction of the active layer. In particular, as the concentration of Al increases, the amount of light emitted to the side may increase. Therefore, there is a problem in that the light propagation path of the light emitted from the semiconductor device is lengthened or absorbed inside the light emitting structure.

The embodiment provides a semiconductor device with improved light extraction efficiency.

A semiconductor device according to an embodiment of the present invention includes a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, , a plurality of first recesses disposed through the second conductive semiconductor layer and the active layer to a partial region of the first conductive semiconductor layer and a second recess disposed between the plurality of first recesses; A light emitting structure comprising; a plurality of first electrodes disposed inside the plurality of first recesses and electrically connected to the first conductive semiconductor layer; and a reflective layer disposed inside the second recess, wherein the plurality of first and second recesses extend in a first direction, and the first direction is perpendicular to a thickness direction of the light emitting structure. .

A length of the second recess in the first direction may be longer than a length of an adjacent first recess in the first direction.

A length of the second recess in the first direction may be 104% or more of a length of an adjacent first recess in the first direction.

An area of the plurality of first recesses may be 30% to 45% based on a maximum area of the light emitting structure in the first direction.

An area of the plurality of second recesses may be 4% to 10% based on a maximum area of the light emitting structure in the first direction.

An area of the plurality of first electrodes may be 19% to 29% based on a maximum area of the light emitting structure in the first direction.

A second electrode disposed on a lower surface of the light emitting structure may be included.

An area of the plurality of second electrodes may be 57% to 86% based on a maximum area of the light emitting structure in the first direction.

A distance between an end of the second recess and a side surface of the light emitting structure may be in a range of 1 μm to 10 μm.

A distance between the plurality of first recesses may be 20 μm to 60 μm.

The reflective layer may be disposed in an area where current density is 40% or less based on 100% current density at the center of the first electrode.

A third recess formed at an edge of the light emitting structure and connecting both ends of the plurality of second recesses may be included.

A side reflector formed inside the third recess may be included.

A capping layer electrically connected to the second electrode may be included.

The capping layer may be disposed higher than the active layer in an edge region of the light emitting structure.

According to an embodiment, light extraction efficiency may be improved.

Also, light output can be improved.

Also, the operating voltage can be improved.

Various advantageous advantages and effects of the present invention are not limited to the above description, and will be more easily understood in the process of describing specific embodiments of the present invention.

1 is a cross-sectional view of a semiconductor device according to a first embodiment of the present invention;
2 is a conceptual diagram showing a process of upwardly reflecting light by a reflective layer;
3 is an enlarged view of part A of FIG. 1;
4 is a view for explaining a height difference between a first recess and a second recess;
5 is a plan view of a semiconductor device according to an embodiment of the present invention;
6 is an enlarged view of part C of FIG. 5,
7 is a photograph of a light emitting structure to which power is applied;
8 is a plan view of a semiconductor device according to a second embodiment of the present invention;
9A and 9C are diagrams showing a semiconductor device according to a third embodiment of the present invention;
10 is a diagram showing a semiconductor device according to a fourth embodiment of the present invention;
11 is a diagram showing a semiconductor device according to a fifth embodiment of the present invention.

The present embodiments may be modified in other forms or combined with each other, and the scope of the present invention is not limited to each of the embodiments described below.

Even if a matter described in a specific embodiment is not described in another embodiment, it may be understood as a description related to another embodiment, unless there is a description contrary to or contradictory to the matter in another embodiment.

For example, if the characteristics of component A are described in a specific embodiment and the characteristics of component B are described in another embodiment, the opposite or contradictory description even if the embodiment in which components A and B are combined is not explicitly described. Unless there is, it should be understood as belonging to the scope of the present invention.

In the description of the embodiment, in the case where an element is described as being formed “on or under” of another element, on or under (on or under) or under) includes both elements formed by directly contacting each other or by indirectly placing one or more other elements between the two elements. In addition, when expressed as "on or under", it may include the meaning of not only the upward direction but also the downward direction based on one element.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention.

1 is a cross-sectional view of a semiconductor device according to an embodiment of the present invention, FIG. 2 is a conceptual diagram showing a process of upwardly reflecting light by a reflective layer, FIG. 3 is an enlarged view of portion A of FIG. 1, and FIG. It is a drawing for explaining the height difference between the first recess and the second recess.

Referring to FIG. 1 , a semiconductor device according to an embodiment includes a light emitting structure 120 including a first conductivity type semiconductor layer 122, a second conductivity type semiconductor layer 126, and an active layer 124, and a first conductivity type semiconductor layer 122. Inside the first electrode 142 electrically connected to the type semiconductor layer 122, the second electrode 146 electrically connected to the second conductivity type semiconductor layer 126, and the second recess 127 A reflective layer 135 is disposed.

The light emitting structure 120 according to the embodiment may output light in an ultraviolet wavelength range. Illustratively, the light emitting structure 120 may output light (UV-A) in a near-ultraviolet wavelength range, may output light (UV-B) in a far-ultraviolet wavelength range, or light (UV-A) in a deep ultraviolet wavelength range. C) can be released. The UV wavelength band may be determined by the Al composition ratio of the light emitting structure 120 .

Illustratively, the light (UV-A) in the near ultraviolet wavelength range may have a wavelength ranging from 320 nm to 420 nm, and the light (UV-B) in the far ultraviolet wavelength range may have a wavelength ranging from 280 nm to 320 nm. The light (UV-C) of the wavelength range may have a wavelength ranging from 100 nm to 280 nm.

The light emitting structure 120 includes a plurality of first recesses 128 penetrating the second conductivity type semiconductor layer 126 and the active layer 124 to a partial region of the first conductivity type semiconductor layer 122, and a plurality of first recesses 128. It includes at least one second recess 127 disposed between the first recesses 128 of the dog.

The first insulating layer 131 may be formed on the first recess 128 and the second recess 127 . The first insulating layer 131 may electrically insulate the reflective layer 135 from the active layer 124 and the first conductive type semiconductor layer 122 . The first insulating layer 131 may extend from the first recess 128 and the second recess 127 onto the second conductive semiconductor layer 126 .

The first electrode 142 and the second electrode 146 may be ohmic electrodes. The first electrode 142 and the second electrode 146 include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), and indium gallium zinc oxide (IGZO). ), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx/ITO, Ni/IrOx/Au, or Ni/IrOx/Au/ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, It may be formed including at least one of Ru, Mg, Zn, Pt, Au, and Hf, but is not limited to these materials.

The reflective layer 135 may be disposed inside the second recess 127 . In detail, the reflective layer 135 may be disposed on the first insulating layer 131 within the second recess 127 .

The reflective layer 135 may be formed of a material having high reflectivity in the UV wavelength range. The reflective layer 135 may include a conductive material. For example, the reflective layer 135 may include Al (aluminum). When the thickness of the aluminum reflective layer 135 is about 30 nm to about 100 nm, more than 80% of light in the ultraviolet wavelength range may be reflected. Accordingly, it is possible to prevent light emitted from the active layer 124 from being absorbed inside the semiconductor layer.

Referring to FIG. 2 , when the Al composition of the light emitting structure 120 increases, current spreading characteristics within the light emitting structure 120 may deteriorate. In addition, the amount of light emitted to the side of the active layer 124 is increased compared to the GaN-based blue light emitting device (TM mode). Such a TM mode may occur in a semiconductor device emitting a wavelength in the ultraviolet region.

According to the embodiment, by etching a region having a low current density and forming the reflective layer 135 , the light L1 may be upwardly reflected by the reflective layer 135 . Accordingly, light absorption within the light emitting structure 120 may be reduced and light extraction efficiency may be improved. Also, the beam angle of the semiconductor device may be adjusted.

The first conductivity-type semiconductor layer 122 may be implemented with compound semiconductors such as group III-V and group II-VI, and the first conductivity-type semiconductor layer 122 may include 1 dopant may be doped. The first conductive semiconductor layer 122 is a semiconductor material having a composition formula of Inx1Aly1Ga1-x1-y1N (0≤x1≤1, 0≤y1≤1, 0≤x1+y1≤1), for example, GaN, AlGaN, It may be selected from InGaN, InAlGaN, and the like. Also, the first dopant may be an n-type dopant such as Si, Ge, Sn, Se, or Te. When the first dopant is an n-type dopant, the first conductivity-type semiconductor layer 122 doped with the first dopant may be an n-type semiconductor layer.

The first conductive type semiconductor layer 122 may have a low concentration layer 122a having a relatively low concentration of Al and a high concentration layer 122b having a relatively high concentration of Al. The high-concentration layer 122b may have an Al concentration of 60% to 70%, and the low-concentration layer 122a may have an Al concentration of 40% to 50%. The low-concentration layer 122a is disposed adjacent to the active layer 124 .

The first electrode 142 may be disposed on the low-concentration layer to secure relatively smooth current injection characteristics. That is, the first recess 128 is preferably formed up to the region of the low-concentration layer 122a. This is because the high-concentration layer 122b has a relatively low current spreading characteristic due to the high concentration of Al.

The active layer 124 is a layer where electrons (or holes) injected through the first conductive semiconductor layer 122 and holes (or electrons) injected through the second conductive semiconductor layer 126 meet. The active layer 124 transitions to a lower energy level as electrons and holes recombine, and may generate light having a wavelength corresponding to the transition.

The active layer 124 may have a structure of any one of a single well structure, a multi-well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, or a quantum wire structure, and the active layer 124 The structure of is not limited to this. The active layer may include Al.

The second conductivity type semiconductor layer 126 is formed on the active layer 124 and may be implemented with a compound semiconductor such as group III-V or group II-VI. Dopants may be doped. The second conductive type semiconductor layer 126 is a semiconductor material having a composition formula of Inx5Aly2Ga1-x5-y2N (0≤x5≤1, 0≤y2≤1, 0≤x5+y2≤1) or AlInN, AlGaAs, GaP, GaAs , GaAsP, may be formed of a material selected from AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, or Ba, the second conductivity-type semiconductor layer 126 doped with the second dopant may be a p-type semiconductor layer.

When the second conductive semiconductor layer 126 is AlGaN, hole injection may not be smooth due to low electrical conductivity. Accordingly, GaN having relatively excellent electrical conductivity may be disposed on the bottom surface of the second conductivity type semiconductor layer 126 .

The thickness d2 of the first electrode 142 may be thinner than the thickness d3 of the first insulating layer 131, and have a separation distance d4 of 0 μm to 4 μm from the first insulating layer 131. can The thickness d2 of the first electrode 142 may be 40% to 80% of the thickness d3 of the first insulating layer 131 .

When the thickness d2 of the first electrode 142 is 40% to 80% of the thickness d3 of the first insulating layer 131, when disposing the second insulating layer 132 and the lower electrode layer 165 It is possible to solve problems such as peeling and cracks caused by deterioration in step coverage characteristics. In addition, the first insulating layer 131 may have a separation distance (d4) of 1 μm to 3 μm more preferably from the first electrode 142, and by having a preferable separation distance, the second insulation layer 132 The gap-fill characteristics of can be improved.

Referring to FIG. 3 , the reflective layer 135 may cover one side surface and a part of the top surface of the second electrode 146 . With this configuration, light introduced between the first insulating layer 131 and the second electrode 146 can be reflected upward. However, the reflective layer 135 made of aluminum has relatively poor step coverage, and leakage current may occur due to migration characteristics, thereby degrading reliability. Therefore, it may not be desirable for the reflective layer 1355 to completely cover the second electrode 146 .

The second electrode 146 may be disposed on the lower surface 121 of the light emitting structure. The thickness of the second electrode 146 may be 80% or less of the thickness of the first insulating layer 131 . Accordingly, when the reflective layer 135 and the capping layer 150 are disposed, problems such as cracks or peeling of the reflective layer 135 or the capping layer 150 due to a decrease in step coverage may be solved.

A distance S1 between the plurality of second electrodes may range from 3 μm to 60 μm. When the distance S1 between the plurality of second electrodes is smaller than 3 μm, the width of the second recess 127 becomes small, making it difficult to form the reflective layer 135 therein. In addition, when the distance exceeds 60 μm, the area of the second electrode 146 may be reduced, resulting in an increase in operating voltage and a decrease in light output due to a problem of removing an effective light emitting region.

The width S2 of the reflective layer may be 3 μm to 30 μm. If the width S2 of the reflective layer is less than 3 μm, it is difficult to form the reflective layer in the second recess 127, and if it exceeds 30 μm, the area of the second electrode 146 is reduced, resulting in an increase in operating voltage. .

A width S2 of the reflective layer 135 may be the same as that of the second recess 127 . The width of the first recess and the width of the second recess 127 may be the maximum width formed on the lower surface 121 of the light emitting structure.

The reflective layer 135 may include an extension 135a extending from the second recess 127 toward the second electrode 146 . The extension part 135a may electrically connect the second electrodes 146 separated by the second recess 127 to each other.

A width S5 of the extension 135a may be in the range of 0 μm to 20 μm. When the width S5 is greater than 20 μm, since the area where the second electrode 146 and the extension portion 135a vertically overlap is too wide, peeling may occur due to a difference in thermal expansion coefficient. A width S4 of the reflective layer including the extension part 135a may be 20 μm to 60 μm.

The second electrode 146 may have a first separation distance S3 from the first insulating layer 131 of 0 μm to 4 μm. When the separation distance is longer than 4 μm, the area where the second electrode 146 is disposed is narrowed, and thus the operating voltage may increase. The first insulating layer 131 and the second electrode 146 may more preferably have a separation distance S3 of 1 μm to 4 μm. When the reflective layer 135 is disposed within the desired separation distance S3, it can be sufficiently disposed to satisfy a gap-fill characteristic.

The reflective layer 135 may be disposed at a first separation distance S3 between the second electrode 146 and the first insulating layer 131, and within the first separation distance S3, the reflective layer 135 is the first separation distance S3. It may contact the side surface and top surface of the insulating layer 131 and the side surface and top surface of the second electrode 146 . In addition, a region in which the reflective layer 135 and the second conductive type semiconductor layer 126 are formed may be disposed within the first separation distance S3, and current distribution may be facilitated by forming the Schottky junction. can

An angle θ4 formed between the inclined portion of the reflective layer 135 and the lower surface of the second conductive type semiconductor layer 126 may range from 90 degrees to 145 degrees. When the inclination angle θ4 is less than 90 degrees, it is difficult to etch the second conductive type semiconductor layer 126, and when it is greater than 145 degrees, the area of the active layer to be etched increases, resulting in a decrease in luminous efficiency.

The capping layer 150 may cover the reflective layer 135 and the second electrode 146 . Accordingly, the second electrode pad 166, the capping layer 150, the reflective layer 135, and the second electrode 146 may form one electrical channel.

The capping layer 150 completely surrounds the reflective layer 135 and the second electrode 146 and may contact side surfaces and top surfaces of the first insulating layer 131 . The capping layer 150 is made of a material having good adhesion to the first insulating layer 131, and includes at least one material selected from the group consisting of materials such as Cr, Al, Ti, Ni, Au, and alloys thereof. It may be made of a single layer or a plurality of layers.

When the capping layer 150 contacts the side surface and top surface of the first insulating layer 131 , thermal and electrical reliability of the reflective layer 135 and the second electrode 146 may be improved. In addition, light emitted in the direction of the substrate 170 after passing through a partial area of the first insulating layer 131 and emitted between the first insulating layer 131 and the second electrode 146 and emitted in the direction of the substrate 170 It may have a reflective function of reflecting light upward.

The capping layer 150 may be disposed at the second separation distance S6 between the first insulating layer 131 and the second electrode 146 . The capping layer 150 may contact the side surface and top surface of the second electrode 146 and the side surface and top surface of the first insulating layer 131 at the second separation distance S6 . In addition, a region where the capping layer 150 and the second conductive semiconductor layer 126 contact each other within the second separation distance to form a Schottky junction may be disposed, and current dissipation may be facilitated by forming the Schottky junction. .

Referring back to FIG. 1 , the lower electrode layer 165 and the bonding layer 160 may be disposed along the shape of the lower surface of the light emitting structure 120 and the first recess 128 and the second recess 127. there is. The lower electrode layer 165 may be made of a material having excellent reflectivity. Illustratively, the lower electrode layer 165 may include aluminum. When the lower electrode layer 165 includes aluminum, light emitted from the active layer 124 toward the substrate 170 may be upwardly reflected to improve light extraction efficiency.

The second insulating layer 132 electrically insulates the reflective layer 135 , the second electrode 146 , and the capping layer 150 from the lower electrode layer 165 . The lower electrode layer 165 may be electrically connected to the first electrode 142 through the second insulating layer 132 .

The thickness of the first insulating layer 131 may be 40% to 80% of the thickness of the second insulating layer 132 . When 40% to 80% is satisfied, the thickness of the first insulating layer 131 is reduced, and the upper surface of the reflective layer 135 is closer to the first conductive type semiconductor layer 122, so light extraction efficiency can be improved.

For example, the thickness of the first insulating layer 131 may be 3000 angstroms to 7000 angstroms. If it is thinner than 3000 angstroms, electrical reliability may deteriorate, and if it is thicker than 7000 angstroms, when the reflective layer 135 and the capping layer 150 are disposed on the top and side surfaces of the first insulating layer 131, the reflective layer 135 However, since the step coverage characteristics of the capping layer 150 are not good, peeling or cracking may occur. When peeling or cracking occurs, electrical reliability may deteriorate or light extraction efficiency may deteriorate.

The second insulating layer 132 may have a thickness of 4000 angstroms to 10000 angstroms. If it is thinner than 4000 angstroms, electrical reliability may be deteriorated during device operation, and if it is thicker than 10000 angstroms, reliability may be deteriorated due to pressure or thermal stress applied to the device during processing, and the unit cost of the device due to the long process time can cause problems with an increase in The thicknesses of the first insulating layer 131 and the second insulating layer 132 are not limited thereto.

The bonding layer 160 may include a conductive material. For example, the bonding layer 160 may include a material selected from the group consisting of gold, tin, indium, aluminum, silicon, silver, nickel, and copper, or an alloy thereof.

The substrate 170 may be made of a conductive material. For example, the substrate 170 may include a metal or semiconductor material. The substrate 170 may be a metal having excellent electrical conductivity and/or thermal conductivity. In this case, the heat generated during operation of the semiconductor device can be quickly dissipated to the outside.

The substrate 170 may include a material selected from the group consisting of silicon, molybdenum, silicon, tungsten, copper, and aluminum, or an alloy thereof.

The second electrode pad 166 may be made of a conductive material. The second electrode pad 166 may have a single-layer or multi-layer structure, and may include titanium (Ti), nickel (Ni), silver (Ag), and gold (Au). For example, the second electrode pad 166 may have a structure of Ti/Ni/Ti/Ni/Ti/Au.

The second electrode pad 166 may have a concave portion and a convex portion on an upper surface of the second electrode pad 166 having a depressed central portion. A wire (not shown) may be bonded to the concave portion of the upper surface. Therefore, the bonding area is widened, and the second electrode pad 166 and the wire can be more firmly bonded.

Since the second electrode pad 166 can reflect light, light extraction efficiency can be improved as the second electrode pad 166 is closer to the light emitting structure 120 .

The distance between the second electrode pad 166 and the light emitting structure 120 may be 5 μm to 30 μm. If it is smaller than 5 μm, it is difficult to secure a process margin, and if it is larger than 30 μm, the area where the second electrode pad 166 is disposed in the entire device increases, so the area of the light emitting layer 24 may decrease and the amount of light may decrease.

The height of the convex portion of the second electrode pad 166 may be higher than that of the active layer 124 . Accordingly, the second electrode pad 166 reflects light emitted from the active layer 124 in the horizontal direction of the device upward, thereby improving light extraction efficiency and controlling the beam angle.

Concavo-convex may be formed on an upper surface of the light emitting structure. Such irregularities may improve extraction efficiency of light emitted from the light emitting structure 120 . The irregularities may have different average heights depending on the wavelength of the ultraviolet light. In the case of UV-C, light extraction efficiency may be improved when the irregularities have a height of about 300 nm to about 800 nm and an average height of about 500 nm to about 600 nm.

A passivation layer 180 may be disposed on top and side surfaces of the light emitting structure 12 . The thickness of the passivation layer 180 may be 2000 angstroms to 5000 angstroms. If it is less than 2000 angstroms, it is not sufficient to protect the device from external moisture or foreign substances, and the electrical and optical reliability of the device may be deteriorated. If it is thicker than 5000 angstroms, the stress applied to the device increases, reducing optical reliability However, as the process time increases, the cost of the device may increase.

Referring to FIG. 4 , the protrusion height H ₁ of the second recess 127 may be greater than the protrusion height H ₂ of the first recess 128 . Here, the protrusion height may be defined as a vertical distance from the active layer 124 to the upper surfaces of the first recess 128 and the second recess 127 .

Specifically, the protruding height H ₁ of the second recess 127 may satisfy the following relational expression 1.

[Relationship 1]

H ₁ =W ₄ ×tan(θ ₁ )

Here, W ₄ is the distance from the midpoint C1 between the adjacent first and second recesses 128 and 127 to the upper surface C2 of the second recess, and θ ₁ is 0.5 degrees. or more and less than 5.0 degrees.

When θ ₁ is less than 0.5 degrees, the height of the reflective layer is relatively low, making it difficult to perform an effective reflective function. In addition, when the angle exceeds 5.0 degrees, the height of the reflective layer is too high, so there is a problem in that the area of the active layer is excessively reduced in proportion thereto. In addition, there is a problem in that the recess process and the insulating layer process must be more precisely managed.

For example, the distance from the intermediate point C1 to the upper surface C2 of the second recess is 20 μm to 40 μm, and θ1 may be 2.3 degrees. The protrusion height of the second recess 127 may be about 300 nm to about 800 nm. In this case, light emitted in the TM mode from the active layer 124 can be effectively reflected upward.

The second recess 127 may be formed higher than the first recess 128 . However, it is not necessarily limited thereto, and the height of the first recess 128 and the height of the second recess 127 may be the same.

The inclination angle θ ₂ of the first recess 128 is 40 degrees to 70 degrees, or 60 degrees to 70 degrees, and the inclination angle θ ₃ of the second recess 127 is 40 degrees to 70 degrees, Or it may be 60 degrees to 70 degrees.

FIG. 5 is a plan view of a semiconductor device according to an embodiment of the present invention, and FIG. 6 is an enlarged view of part C of FIG. 5 , and FIG. 7 is a photograph of a light emitting structure to which power is applied.

Referring to FIGS. 5 and 6 , the first recesses 128 may extend in a first direction (X direction) and be spaced apart in a second direction (Z direction). Here, the first direction may be a direction perpendicular to the thickness direction (Y direction) of the light emitting structure 120 . Hereinafter, the width (area) of the first recess 128 and the second recess 127 is defined as a region formed under the light emitting structure 120 .

A first electrode 142 may be disposed inside the first recess 128 . The area of the first electrode 142 may be controlled by adjusting the number of the first recesses 128 or adjusting the length extending in the first direction.

Since current dissipation is relatively difficult in the UV light emitting structure having a high aluminum concentration, it is necessary to increase the area of the first electrode compared to the GaN light emitting structure emitting blue light. In the embodiment, since the plurality of first electrodes 142 contact the first conductive semiconductor layer in the first direction, a current injection area can be increased.

At this time, when the first recess 128 is excessively formed to increase the area of the first electrode 142, the area of the active layer 124 and the second electrode 146 decreases, so maintaining an appropriate area ratio It is important.

The width W1 of the first recess 128 may be greater than or equal to 30 μm and less than or equal to 60 μm. When the width W1 of the first recess 128 is smaller than 30 μm, it is difficult to secure a process margin in forming the first electrode 142 therein, and when the width W1 of the first recess 128 is larger than 60 μm, the active layer is excessively reduced. Light output may be lowered.

The distance d6 between the first recesses 128 may range from 20 μm to 60 μm. When the distance d6 is less than 20 μm, the active layer may be excessively reduced and light output may be lowered. When the distance is greater than 60 μm, the number of first recesses 128 is reduced and the It is difficult to secure enough space.

The area of the plurality of first electrodes 142 may be 19% to 29% based on 100% of the maximum area of the light emitting structure 120 in the first direction. If the area of the first electrode 142 is less than 19%, sufficient current injection and diffusion may be difficult, and if the area of the first electrode 142 is greater than 29%, the active layer 124 and the second electrode 146 ) There is a problem in that the area in which ) can be disposed is reduced, and the light output is lowered and the operating voltage is increased.

The area of the plurality of first recesses 128 may be 30% to 45% based on 100% of the maximum area of the light emitting structure 120 in the first direction. When the area of the first recess 128 is less than 30%, the area of the first electrode 142 becomes small, and when the area of the first recess 128 is greater than 45%, the active layer 124 There is a problem in that an area in which the second electrode 146 and the second electrode 146 can be disposed is reduced so that the light output is lowered and the operating voltage is increased.

The plurality of second recesses 127 may extend in a first direction (X direction) and be spaced apart in a second direction (Y direction). The second recess 127 may be disposed between the plurality of first recesses 128 .

The reflective layer 135 may be disposed inside the second recess 127 . Accordingly, the reflective layer 135 may be disposed on both side surfaces of the plurality of first electrodes 142 to upwardly reflect light emitted from the periphery of the first electrodes 142 . The width S2 of the reflective layer 135 may be equal to or greater than the width of the second recess 127 .

As the composition of aluminum increases, the current dissipation effect may be weakened. Accordingly, the current is distributed only to points near each of the first electrodes 142, and the current density may rapidly decrease at points far away from each other. Accordingly, the effective light emitting region P2 is narrowed.

The effective light emitting region P2 may be defined as a boundary point where the current density is 30% to 40% or less based on the center of the first electrode 142 where the current density is 100%. For example, a distance 5 μm to 40 μm away from the center of the first recess 128 in the second direction may be defined as the boundary point. However, it may be variable according to the level of the injection current and the concentration of Al.

The reflective layer 135 may be disposed at a boundary point where the current density is 30% to 40% or less. That is, in the embodiment, the light extraction efficiency may be improved by forming the reflective layer 135 in an area where the current density is low.

The length of the second recess 127 in the first direction may be longer than the length of the adjacent first recess 128 in the first direction. If the length of the second recess 127 is equal to or shorter than the length of the adjacent first recess 128, light emitted from the end point of the first recess 128 cannot be controlled.

Here, the first recesses 128 adjacent to the second recess 127 are two first recesses 128 disposed closest to the second recess 127 in the second direction (Z direction). can That is, the second recess 127 may be formed to be longer than at least one of the two first recesses 128 disposed adjacent to each other.

One end of the second recess 127 may be longer than one end of the first recess 128 (d5). A length of the second recess 127 in the first direction may be 104% or more of a length of the first recess 128 disposed adjacent thereto in the first direction. In this case, light emitted from the periphery of both ends of the first electrode 142 can be effectively upwardly reflected.

A distance d1 between the second recess 127 and the side surface of the light emitting structure 120 may range from 1.0 μm to 10 μm. When the separation distance d1 is less than 1.0 μm, it is difficult to secure a process margin and it is difficult to arrange the capping layer 150 while covering the reflective layer 135, and thus reliability may deteriorate. In addition, when the separation distance d1 is greater than 10 μm, an area participating in light emission is reduced, and thus light extraction efficiency may decrease. However, it is not necessarily limited thereto, and the second recess 127 and the reflective layer 135 may be formed up to the side of the light emitting structure 120 .

The area of the plurality of second recesses 127 may be 4% to 10% based on 100% of the maximum area of the light emitting structure 120 in the first direction. When the area of the second recess 127 is smaller than 4%, it is difficult to form the reflective layer 135 inside the second recess 127 . In addition, when the area of the second recess 127 is greater than 10%, the area of the active layer is reduced and light output may be weakened.

The area of the reflective layer 135 may be 46% to 70% based on 100% of the maximum area of the light emitting structure 120 in the first direction. An area of the reflective layer 135 that actually reflects light may be equal to or smaller than an area of the second recess 127 . The area of the reflective layer 135 here is an area including an extension extending to the lower surface of the light emitting structure 120 and covering the second electrode 146 .

The area of the second electrode 146 may be 57% to 86% based on 100% of the maximum area of the light emitting structure 120 in the first direction. If the area of the second electrode 146 is less than 57%, the operating voltage may increase, and if the area is greater than 86%, the area of the first electrode 142 may decrease, resulting in lower current injection and dissipation efficiency. .

The area of the second electrode 146 may be an area remaining after excluding areas of the first recess 128 and the second recess 127 in the light emitting structure 120 . Accordingly, the second electrode 146 may be one electrode connected as a whole.

8 is a plan view of a semiconductor device according to a second embodiment of the present invention, FIG. 9 is a view showing a semiconductor device according to a third embodiment of the present invention, and FIG. 10 is a semiconductor device according to a fourth embodiment of the present invention. 11 is a diagram showing a semiconductor device according to a fifth embodiment of the present invention.

Referring to FIG. 8 , side reflectors 135b connected to both ends of the plurality of reflective layers 135 may be included. That is, the third recess 129 may be formed at the edge of the light emitting structure 120 , and the side reflector 135b may be formed inside the third recess 129 . The reflective layer 135 and the side reflector 135b may include the same reflective material. For example, the reflective layer 135 and the side reflector 135b may include aluminum.

The plurality of reflective layers 135 and the side reflectors 135b may be electrically connected or spaced apart from each other.

When the plurality of reflective layers 135 and the side reflectors 135b are connected to each other, a plurality of first regions 136 may be formed. The plurality of first regions 136 may be spaced apart from each other by the plurality of reflective layers 135 .

A first recess 128 and a first electrode 142 may be disposed in each of the plurality of first regions 136 . According to this configuration, light emitted around both ends of the first electrode 142 can be reflected upward effectively.

The second electrode may be divided into a plurality of pieces by the second recess 127 and the third recess. The plurality of divided second electrodes 146 may be electrically connected to each other by extensions of the reflective layer 135 .

Referring to FIG. 9A , the reflective layer 135 may not be disposed at the edge of the light emitting device. That is, the reflective layer 135 or the first electrode 142 may be disposed at the edge for various reasons such as a process margin.

Referring to FIG. 9B , the capping layer 150, the lower electrode layer 165, and the substrate 70 protrude from the edge portion Z1 of the semiconductor device to upwardly reflect the light L2 emitted from the active layer 124. can That is, the side reflector may be formed at the edge portion Z1 of the semiconductor device. Accordingly, light emitted from the outermost shell can be upwardly reflected without forming a separate reflective layer.

An angle between the capping layer 150 and the lower surface of the second conductive type semiconductor layer 126 may range from 90 degrees to 145 degrees. When the angle is less than 90 degrees or greater than 145 degrees, the efficiency of reflecting light moving toward the side to the upper side may decrease.

According to this configuration, light emitted between the plurality of first recesses 128 is upwardly reflected by the reflective layer 135, and light emitted from the edge of the light emitting structure 120 is upwardly reflected by the capping layer 150. can

Referring to FIG. 10 , the plurality of reflective layers 135 may extend in a second direction (Z direction) and be spaced apart in a first direction (X direction). The arrangement of the first recess 128 and the second recess 127 may be appropriately modified according to the location of the electrode pad.

Referring to FIG. 11 , the first recess 128 and the first electrode 142 may extend in the first direction and the second direction, respectively. Accordingly, a plurality of second regions 137 may be formed in regions where the first recesses 128 intersect each other.

A plurality of reflective layers 135 may be disposed in the second region 137 to reflect light upward. A side reflector 135b may be disposed at an edge of the light emitting structure 120 . The plurality of reflective layers 135 and the side reflector 135b may be electrically connected to each other through the second electrode. However, it is not necessarily limited thereto, and the plurality of reflective layers 135 and the side reflector 135b may be electrically insulated.

The semiconductor device is configured as a package and may be used for curing of resin, resist, SOD, or SOG. Alternatively, the semiconductor device may be used for medical treatment or for sterilization of air purifiers or water purifiers.

In addition, the semiconductor device may be used as a light source of a lighting system, a light source of an image display device or a light source of a lighting device. That is, the semiconductor element may be applied to various electronic devices disposed in a case to provide light. Illustratively, when a semiconductor device and an RGB phosphor are mixed and used, white light having excellent color rendering index (CRI) can be implemented.

The semiconductor device described above is configured as a light emitting device package and can be used as a light source of a lighting system, for example, a light source of an image display device or a light source of a lighting device.

When used as a backlight unit of an image display device, it can be used as an edge-type backlight unit or a direct-type backlight unit, and when used as a light source for a lighting device, it can be used as a lamp or bulb type, and can also be used as a light source for mobile terminals. may be

The light emitting element includes a laser diode in addition to the light emitting diode described above.

Like the light emitting device, the laser diode may include the first conductivity type semiconductor layer, the active layer, and the second conductivity type semiconductor layer having the above structure. In addition, an electro-luminescence phenomenon in which light is emitted when a current is passed after bonding a p-type first conductivity type semiconductor and an n-type second conductivity type semiconductor is used, but the directionality of the emitted light There is a difference between and phase. That is, a laser diode can emit light having a specific wavelength (monochromatic beam) with the same phase and in the same direction by using a phenomenon called stimulated emission and a constructive interference phenomenon. Due to this, it can be used for optical communication, medical equipment, and semiconductor processing equipment.

A photodetector, which is a type of transducer that detects light and converts its intensity into an electrical signal, may be exemplified as the light receiving element. As such an optical detector, a photovoltaic cell (silicon, selenium), an optical output device (cadmium sulfide, cadmium selenide), a photodiode (eg, a PD having a peak wavelength in a visible blind spectral region or a true blind spectral region), a photodetector Transistors, photomultiplier tubes, photoelectric tubes (vacuum, gas filled), IR (Infra-Red) detectors, etc., but embodiments are not limited thereto.

In addition, a semiconductor device such as a photodetector may be fabricated using a direct bandgap semiconductor having excellent light conversion efficiency. Alternatively, photodetectors have various structures, and the most common structures include a pin type photodetector using a p-n junction, a Schottky type photodetector using a Schottky junction, and a Metal Semiconductor Metal (MSM) type photodetector. there is.

Like a light emitting device, a photodiode may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer having the above-described structure, and has a pn junction or pin structure. The photodiode operates by applying reverse bias or zero bias, and when light is incident on the photodiode, electrons and holes are generated and current flows. In this case, the size of the current may be substantially proportional to the intensity of light incident on the photodiode.

A photovoltaic cell or solar cell is a type of photodiode and can convert light into electric current. A solar cell, like a light emitting device, may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer having the above structure.

In addition, it can be used as a rectifier of an electronic circuit through the rectification characteristics of a general diode using a p-n junction, and can be applied to an oscillation circuit by being applied to a microwave circuit.

In addition, the above-described semiconductor device is not necessarily implemented as a semiconductor and may further include a metal material in some cases. For example, a semiconductor device such as a light receiving device may be implemented using at least one of Ag, Al, Au, In, Ga, N, Zn, Se, P, or As, and may be implemented using a p-type or n-type dopant. It may be implemented using a doped semiconductor material or an intrinsic semiconductor material.

Although the above has been described with reference to the embodiments, this is only an example and does not limit the present invention, and those skilled in the art to which the present invention belongs will not deviate from the essential characteristics of the present embodiment. It will be appreciated that various variations and applications are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention as defined in the appended claims.

Claims (15)

a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer;
a plurality of first recesses passing through the second conductive semiconductor layer and the active layer to a partial region of the first conductive semiconductor layer and a second recess disposed between the plurality of first recesses; a light emitting structure;
a plurality of first electrodes disposed inside the plurality of first recesses and electrically connected to the first conductive semiconductor layer;
a reflective layer disposed inside the second recess; and
Including; a second electrode disposed on the lower surface of the light emitting structure,
The plurality of first and second recesses extend in a first direction;
The first direction is a direction perpendicular to the thickness direction of the light emitting structure,
The reflective layer includes an extension portion extending from the second recess toward the second electrode,
The extension portion covers a portion of a side surface and an upper surface of the second electrode and is electrically connected to the second electrode.
According to claim 1,
A length of the second recess in the first direction is longer than a length of at least one of the adjacent first recesses in the first direction.
According to claim 1,
A length of the second recess in the first direction is 104% or more of a length of the adjacent first recess in the first direction.
According to claim 1,
An area of the plurality of first recesses is 30% to 45% of a maximum area of the light emitting structure in the first direction.
According to claim 1,
The area of the plurality of second recesses is 4% to 10% of the light emitting structure in the first direction.
According to claim 1,
An area of the plurality of first electrodes is 19% to 29% of a maximum area of the light emitting structure in the first direction.
delete According to claim 1,
An area of the plurality of second electrodes is 57% to 86% of a maximum area of the light emitting structure in the first direction.
According to claim 1,
The semiconductor device of claim 1 , wherein a distance between an end of the second recess and a side surface of the light emitting structure is in a range of 1 μm to 10 μm.
According to claim 1,
A semiconductor device wherein a distance between two adjacent first recesses is in a range of 20 μm to 60 μm.
According to claim 1,
The reflective layer is disposed in a region in which a current density is 40% or less based on a current density of 100% at the center of the first electrode.
According to claim 1,
A semiconductor device comprising a third recess formed at an edge of the light emitting structure and connecting both ends of the plurality of second recesses.
According to claim 12,
A semiconductor device comprising a side reflector formed inside the third recess.
According to claim 1,
A semiconductor device comprising a capping layer electrically connected to the second electrode.
According to claim 14,
The capping layer is disposed higher than the active layer in the edge region of the light emitting structure semiconductor device.

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