KR102510596B1 - Semiconductor device - Google Patents

Abstract

In an embodiment, a first recess region includes a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, and extends from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer through the active layer. A light emitting structure comprising a; a first electrode layer contacting the first conductivity-type semiconductor layer in the first recess region; a second electrode layer in contact with the second conductivity type semiconductor layer; and a first reflective layer electrically connected to the second electrode layer and extending from an edge region of the light emitting structure to a region higher than the active layer.

Description

Semiconductor device {SEMICONDUCTOR DEVICE}

Embodiments relate to semiconductor devices, and more particularly, to semiconductor devices with improved light extraction efficiency.

A light emitting device including compounds such as GaN and AlGaN has many advantages, such as having a wide band gap energy that is easily adjustable, and can be used in various ways such as a light emitting device, a light receiving device, 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.

Therefore, the light emitting element 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, a light emitting structure including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer is disposed on a substrate, a first electrode is disposed on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer is disposed. A second electrode may be disposed on the conductive semiconductor layer.

Light generated from the active layer of the semiconductor device may propagate not only to the top of the active layer but also to the side and bottom of the active layer. Therefore, when the light emitted from the semiconductor device progresses in the lateral direction, the traveling path increases or is absorbed inside the light emitting structure, thereby reducing light extraction efficiency.

The embodiment seeks to improve the light extraction efficiency of a semiconductor device and control the beam angle.

In an embodiment, a first recess region includes a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, and extends from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer through the active layer. A light emitting structure comprising a; a first electrode layer contacting the first conductivity-type semiconductor layer in the first recess region; a second electrode layer in contact with the second conductivity type semiconductor layer; and a first reflective layer electrically connected to the second electrode layer and extending from an edge region of the light emitting structure to a region higher than the active layer.

The first reflective layer may directly contact the second conductivity type semiconductor layer in a peripheral area of the second electrode layer.

The first reflective layer may have a layer structure of aluminum, titanium, gold, and titanium.

An edge region of the light emitting structure may be removed from the second conductivity-type semiconductor layer to a portion of the active layer and the first conductivity-type semiconductor layer, and the first reflective layer may be disposed in the region from which the light emitting structure is removed.

The distance between the lower surface of the second conductive semiconductor layer of the light emitting structure and the outermost periphery of the light emitting structure may be within 3 to 7 micrometers.

The semiconductor device further includes a second electrode disposed on a surface of the second conductivity-type semiconductor layer and electrically connected to the first reflective layer, and a first insulating layer disposed on a surface of the second conductivity-type semiconductor layer. A width of a region where the surface of the two-conductivity semiconductor layer and the first insulating layer contact each other may range from 5 micrometers to 15 micrometers.

The edge of the surface of the second conductivity-type semiconductor layer and the edge of the second electrode layer may be spaced apart from each other by 5 micrometers to 15 micrometers.

In the edge region of the light emitting structure, the side of the light emitting structure may form an angle greater than 90 degrees and less than 150 degrees with respect to the bottom surface of the light emitting structure.]

In another embodiment, a first recess includes a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, and extends from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer through the active layer. a light emitting structure including an area and a second recess area and emitting light in an ultraviolet wavelength range; a first electrode layer contacting the first conductivity-type semiconductor layer in the first recess region; a second electrode layer in contact with the second conductivity type semiconductor layer; a first reflective layer electrically connected to the second electrode layer and extending from an edge region of the light emitting structure to a region higher than the active layer; and a second reflective layer disposed in the second recess region.

The height of the first recessed area may be the same as that of the second recessed area.

A width of the first recess area may be greater than a width of the second recess area.

A portion of the first reflective layer may overlap the second reflective layer in a vertical direction.

The second reflective layer may be disposed in a region where the current intensity is 30% to 40% of I ₀ , and the I ₀ may be the current intensity in the first conductivity type semiconductor layer contacting the first electrode layer.

Another embodiment includes a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer, and a first ridge extending from the second conductivity-type semiconductor layer to the first conductivity-type semiconductor layer through the active layer. a light emitting structure including a access region and emitting light in an ultraviolet wavelength region; a first electrode layer contacting the first conductivity-type semiconductor layer in the first recess region; a second electrode layer in contact with the second conductivity type semiconductor layer; and a third reflective layer at least partially disposed inside the first recess region.

An upper surface of the third reflective layer may be disposed higher than that of the active layer.

A bottom surface of the third reflective layer may be disposed under the first recess region and at least partially overlap the second conductivity type semiconductor layer in a vertical direction.

The third reflective layer may be electrically connected to the first electrode layer.

A lower reflective layer may be further included and spaced apart from the lower portion of the light emitting structure, and the third reflective layer may be spaced apart from the lower reflective layer.

A lower reflective layer spaced apart from the lower portion of the light emitting structure may be included, and the third reflective layer may electrically contact the lower reflective layer.

In an exemplary embodiment, since the semiconductor device includes aluminum and may have a low current density, the first to third reflective layers may be formed to adjust the beam angle and improve light extraction efficiency.

In particular, a light emitting device emitting light in the UV-B or UV-C wavelength region has a light emitting structure grown on the basis of AlGaN, and compared to a light emitting device emitting light in the blue wavelength region, the light emitting device emits light in the TE mode. Polarization can be increased to the TM mode in which light emission in a parallel direction is dominant. In this case, light traveling in a lateral direction in the active layer may be reflected by the first to third reflective layers.

1 is a plan view of a first embodiment of a semiconductor device.
FIG. 2 is a cross-sectional view of the semiconductor device of FIG. 1 in the direction HH'.
3 is a view showing a part of FIG. 2 in detail.
4 to 6 are diagrams showing parts of second to fourth embodiments of semiconductor devices in detail.
7 is a plan view of a fifth embodiment of a semiconductor device.
FIG. 8 is a cross-sectional view of the semiconductor device of FIG. 7 in the KK′ direction.
9 is a view illustrating a package in which semiconductor elements are disposed.

Hereinafter, embodiments of the present invention that can specifically realize the above object will be described with reference to the accompanying drawings.

In the description of the embodiment according to the present invention, in the case of being described as being formed on "on or under" of each 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.

The semiconductor device may include various electronic devices such as a light emitting device and a light receiving device, and both the light emitting device and the light receiving device may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer.

A semiconductor device according to the present embodiment may be a light emitting device.

A light emitting device emits light by recombination of electrons and holes, and the wavelength of this light is determined by the energy band gap inherent in a material. Thus, emitted light may vary depending on the composition of the material.

When the light emitting structure includes AlGaN having a large Al composition ratio, it can emit light in the ultraviolet, especially deep ultraviolet wavelength region. Ultraviolet light may have a wavelength in the range of, for example, 10 nanometers to 400 nanometers, UV-A (near ultraviolet ray) may have a wavelength in the range of, for example, 320 nanometers to 400 nanometers, and UV-B ( Far ultraviolet rays) may have a wavelength ranging from 280 nanometers to 320 nanometers, and UV-C (deep ultraviolet rays) may have a wavelength ranging from 100 nanometers to 280 nanometers.

FIG. 1 is a plan view of a semiconductor device of a first embodiment, FIG. 2 is a cross-sectional view of the semiconductor device of FIG. 1 in the H-H' direction, and FIG. 3 is a view showing a portion of FIG. 2 in detail.

1, in the semiconductor device, a first electrode layer 242 and a first reflective layer 250 are disposed inside and outside of a plurality of recesses, respectively, and a reflective layer ( A reflective layer is disposed, and the reflective layer may be an extension of the first reflective layer 250 .

In a semiconductor device, a structure composed of a first electrode layer, a recess, and a first reflective layer may actually be formed in a larger number, and the number of recesses may be freely adjusted in consideration of the size, current density, and light output of the semiconductor device. can

The semiconductor device 200A according to the present embodiment includes a semiconductor structure 220 including a first conductivity type semiconductor layer 222, an active layer 224, and a second conductivity type semiconductor layer 226, and a first conductivity type semiconductor layer 220. It may include a first electrode layer 242 contacting the semiconductor layer 222 and a second electrode layer 246 contacting the second conductivity type semiconductor layer 226 .

A recess is provided from the second conductivity type semiconductor layer 226 to the active layer 224 and a portion of the first conductivity type semiconductor layer 226 to expose a plurality of areas where the first conductivity type semiconductor layer 222 is exposed. However, it may be referred to as a recess region, and the cross section of the recess region is, for example, circular, polygonal, elliptical, etc., but is not necessarily limited thereto.

The first electrode layer 242 is disposed under the first conductivity type semiconductor layer 222 exposed in the recess region, and the second conductivity type semiconductor layer 226 between the recess regions A second electrode layer 246 may be disposed on the lower surface of the .

The first conductivity type semiconductor layer 222 may be implemented with a compound semiconductor such as group III-IV or group II-V, and may be doped with a first conductivity type dopant. The first conductivity-type semiconductor layer 222 is AlGaN, a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0≤x≤1, 0≤y≤1, 0≤x+y≤1) , GaN, InAlGaN, AlGaAs, GaP, GaAs, GaAsP, can be grown as any one or more of AlGaInP.

When the first conductivity-type semiconductor layer 222 is an n-type semiconductor layer, the first conductivity-type dopant may include an n-type dopant such as Si, Ge, Sn, Se, or Te. The first conductivity type semiconductor layer 222 may be grown as a single layer or multiple layers, but is not limited thereto.

The active layer 224 may include 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.

The active layer 224 is a well layer and a barrier layer, for example, AlGaN/AlGaN, InGaN/GaN, InGaN/InGaN, AlGaN/GaN, InAlGaN/GaN, GaAs (InGaAs), using compound semiconductor materials of group III-IV elements. , / AlGaAs, GaP (InGaP) / AlGaP may be formed in a pair structure of one or more, but is not limited thereto. The well layer may be formed of a material having an energy band gap smaller than that of the barrier layer.

The second conductivity type semiconductor layer 226 may be implemented with a compound semiconductor such as group III-IV or group II-V, and may be doped with a second conductivity type dopant. The second conductivity-type semiconductor layer 226 is, for example, AlGaN, a semiconductor material having a composition formula of In _x Al _y Ga _{1 -xy} N (0≤x≤1, 0≤y≤1, 0≤x+y≤1) , GaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, may be formed of any one or more of AlGaInP.

When the second conductivity type semiconductor layer 226 is made of AlGaN, hole injection may not be smooth due to low electrical conductivity of AlGaN. You can solve this problem by placing .

When the second conductivity type semiconductor layer 226 is a p-type semiconductor layer, the second conductivity type dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, or Ba. The second conductivity type semiconductor layer 226 may be formed as a single layer or multiple layers, but is not limited thereto.

An upper surface of the first conductivity-type semiconductor layer 222 may have irregularities, which may improve extraction efficiency of light emitted from the semiconductor device 200A. The width may increase from the first conductive semiconductor layer 222 toward the active layer 224, the electron blocking layer, and the second conductive semiconductor layer 226, and the width of the lower structure of the light emitting structure 220 in the etching process. This is because it can be etched more widely.

The height of the light emitting structure 220 may be, for example, 2 to 3 micrometers, and in the case of the light emitting structure 220 emitting ultraviolet light, in order to increase the extraction efficiency of light having a shorter wavelength than the blue wavelength, the upper surface has irregularities. The depth of may be between 3,000 angstroms and 8,000 angstroms, and may have an average depth of about 5,000 angstroms.

A first insulating layer 231 is disposed spaced apart from the first electrode layer 242 by a predetermined distance, and the first insulating layer 231 extends from the exposed surface of the first conductivity type semiconductor layer 22 to the side of the recess region. It may extend to the surface of the second conductivity type semiconductor layer 226 . On the exposed lower surface of the second conductive semiconductor layer 246 , the first insulating layer 231 may be disposed spaced apart from both ends of the second electrode layer 246 by a predetermined distance.

The first insulating layer 231, the second insulating layer 232 and the passivation layer 280, which will be described later, may be made of an insulating material, for example, aluminum oxide or aluminum nitride may be used, and in detail, SiO2 or SiN. this can be used

The first reflective layer 250 surrounds at least a portion of the lower surface and side surface of the second electrode layer 246 and at least a portion of the lower surface and side surface of the first insulating layer 231 and is on the lower surface of the second conductive semiconductor layer 226 . ) may be disposed, the first reflective layer 250 may be made of a conductive material, for example, may be made of metal, in detail, chromium (Cr), aluminum (Al), titanium (Ti), gold ( It may be made of at least one material selected from the group consisting of Au) and nickel (Ni) and alloys thereof.

For example, when the first reflective layer 250 is made of aluminum and light in the ultraviolet wavelength region is emitted from the active layer 224, the thickness of the first reflective layer 250 is 50 nanometers or more, the ultraviolet wavelength region It may be sufficient to reflect more than 80% of the light.

The first reflective layer 250 may act as a capping layer that electrically connects the second electrode layer 246 to the second electrode 266 and surrounds and supports the second electrode layer 246 to secure stability. . In addition, the first reflective layer 250 may contact the insulating layer, and when in contact with the insulating layer, the reliability of the device may be secured because of good adhesion to the insulating layer.

In particular, the semiconductor device 200A emitting light in the UV-B or UV-C wavelength region has a light emitting structure 220 grown on the basis of AlGaN compared to a light emitting device emitting light in the blue wavelength region. Light emission of the TM mode, in which light emission in a direction perpendicular to the growth direction (horizontal direction in FIG. 2) is dominant, may increase. At this time, the light traveling in the lateral direction from the active layer 224 is reflected by the first reflective layer 250 to change the traveling direction of the light and shorten the light path to reduce re-absorption of light within the light emitting structure 220. there is.

For this function, the first reflective layer 250 may be disposed to extend from an edge region of the light emitting structure 220 to a region higher than the active layer 224 .

In FIG. 3, the edge region of the light emitting structure 220 is removed and exposed from the second conductivity type semiconductor layer 226 to the active layer 224 and a portion of the first conductivity type semiconductor layer 222, and the light emitting structure A first reflective layer 250 may be disposed in an area where 220 is removed.

In FIG. 3, the area indicated by the line I-I' is the end of the light emitting structure 220 and can be referred to as a separation area of the light emitting structure 220, and the area indicated by the line J-J' is the surface of the light emitting structure 220, that is, the second conductive area. It may be a region in which the upper surface remains without the mold semiconductor layer 226 being removed.

Here, the distance d1 between the line I-I' and the line J-J' may be 3 micrometers to 7 micrometers, for example, 5 micrometers. If the distance between the I-I' line and the J-J' line is less than 3 micrometers, the mesa etch area is narrowed and it may be difficult to form the first reflective layer 250 having a stepped structure. If the distance is greater than 7 micrometers, the process stability However, a problem in that the volume of the active layer 224 decreases may occur.

The second electrode 266 may be made of a conductive material, may be made of metal, may have a single-layer structure or a multi-layer structure, and in detail, Ti (titanium)/Ni (nickel)/Ti/Ni/Ti/Au (gold ) may have a structure.

Since the second electrode 266 may reflect light, light extraction efficiency may be improved as the second electrode 266 is closer to the light emitting structure 220 . A distance d2 between the second electrode 266 and the end of the light emitting structure 220 in the region indicated by the line II' may be 20 micrometers to 30 micrometers. If the distance d2 is less than 20 micrometers, it may be difficult to form the second insulating layer 280 and secure a process margin. If the distance d2 is greater than 30 micrometers, the second electrode 266 is too far from the light emitting structure 220. Light extraction efficiency may decrease.

The second electrode 266 is disposed after forming a recess in at least one of the first insulating layer 231 and the passivation layer 280 to be electrically connected to the first reflective layer 250. At this time, the first insulating layer 266 is disposed. It may be formed along the step of at least one of the layer 231 and the passivation layer 280 . When the second electrode 266 is formed along the lower step, the upper surface of the second electrode 266 may have a concave surface or a convex surface with respect to the substrate. A concave surface or a convex surface may increase an adhesion area during wire bonding of devices later, and thus may have an effect of improving adhesion.

The depth h1 of the recess region may be the same as the depth h3 from which the light emitting structure 220 is removed to dispose the first reflective layer 250 at the edge of the light emitting structure 220 .

In addition, the side of the light emitting structure 220, in particular, the second conductive semiconductor layer 226 is disposed at an angle θ1 with respect to the lower surface, and the side surface of the first reflective layer 250 has an angle θ2 with respect to the lower surface. , and the above-described angles θ1 and θ2 may be equal to each other.

The sloped structure of the first reflective layer 250 may be formed by removing the edge of the light emitting structure 220 with a slope and removing it by a method such as mesa etching. You can progress upwards. In FIG. 3 , the aforementioned angles θ1 and θ2 may be larger than 90 degrees and smaller than 150 degrees.

The distance d3 between the lower surface of the second conductive semiconductor layer 226 and the contact area of the first insulating layer 231 may be, for example, 5 micrometers to 15 micrometers. If it is smaller than 5 micrometers, it is difficult to secure a process margin, and if it is larger than 15 micrometers, the area in which the second electrode layer 246 can be disposed is reduced, so that the operating voltage of the device can be increased. Also, on the lower surface of the second conductive semiconductor layer 226, the distance d4 of the region where the first insulating layer 231 overlaps the first reflective layer 250 is, for example, 4 micrometers to 8 micrometers. can be If it is smaller than 4 micrometers, it is difficult to secure a process margin that allows the first reflective layer 250 and the first insulating layer 231 to overlap, and if it is larger than 8 micrometers, it is a process margin for electrically separating the first electrode layer 242. is difficult to obtain.

A second insulating layer 232 may be disposed under the first reflective layer 250 and the first insulating layer 231 . The second insulating layer 232 contacts the first conductive semiconductor layer 222 inside the recess region and is disposed covering the edge of the first electrode layer 242 .

The second insulating layer 231 may serve to electrically separate the first electrode layer 242 and the second electrode layer 246 . The second insulating layer 232 may have a thickness of 5,000 angstroms to 13,000 angstroms. If the thickness of the second insulator 232 is smaller than 5,000 angstroms, it is not sufficient to electrically separate the first electrode layer 242 and the second electrode layer 246, and reliability may be lowered. If it is thicker than that, stress generated in the process of bonding the support substrate 270 increases, and reliability may deteriorate.

A lower reflective layer 265 and a bonding layer 260 may be disposed on a lower surface of the second insulating layer in the shape of the recess region and the light emitting structure. The lower reflective layer 265 in the first recessed region may contact the first electrode layer 242 between the second insulating layers 232 .

The lower reflective layer 265 may be made of a material having excellent reflectivity, for example, aluminum (Al), and in the ultraviolet wavelength region, it should be provided with a thickness of, for example, 500 angstroms or more to secure a light reflectance of 80% or more. can

The bonding layer 260 includes a region in which the lower reflective layer 265 is bonded to the lower support substrate 270 by diffusion bonding or eutectic bonding including a region in which Ni, Sn, Au, etc. are mixed. can be an area.

The bottom surface of the bonding layer 260 is formed along the step created by the separation distance d0 between the second electrode layer 246 and the first insulating layer 231 disposed on the bottom surface of the second conductivity type semiconductor layer 226, thereby forming the semiconductor element. It may have protrusions in the thickness direction, and if the thickness is sufficiently thick, it may have a flat bottom surface.

The distance d0 between the second electrode layer 246 and the first insulating layer 231 may be, for example, 1 to 2 micrometers. ) may contact the first reflective layer 250 . The separation distance d0 can be secured through self-alignment.

The bonding layer 260 may be made of a conductive material, for example, gold (Au), tin (Sn), indium (In), aluminum (Al), silicon (Si), silver (Ag), or nickel (Ni). ) and a material selected from the group consisting of copper (Cu) or an alloy thereof. The anti-diffusion layer prevents a material constituting the bonding layer 260 generated during the bonding process from being diffused to the periphery of the first electrode layer 242, thereby reducing reliability.

A diffusion barrier layer (not shown) may be disposed between the lower reflective layer 265 and the bonding layer 260. The diffusion barrier layer may have, for example, a multilayer structure of titanium/nickel/titanium/nickel. .

The support substrate 270 may be made of a conductive material, and may be formed of, for example, a metal or semiconductor material. The material of the support substrate 270 may be a metal having excellent electrical or thermal conductivity, and since it should be able to sufficiently dissipate heat generated during operation of the light emitting device, it may be formed of a material having high thermal conductivity. For example, it may be made of a material selected from the group consisting of silicon (Si), molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu), and aluminum (Al) or an alloy thereof, In addition, gold (Au), copper alloy (Cu Alloy), nickel (Ni), copper-tungsten (Cu-W), carrier wafer (eg GaN, Si, Ge, GaAs, ZnO, SiGe, SiC, SiGe, Ga2O3 etc.), etc. may optionally be included.

When a semiconductor device is formed on the basis of AlGaN, if a large amount of aluminum (Al) is included, the current spreading property in the light emitting structure is deteriorated. In particular, the light emitting device emitting light in the UV-B or UV-C wavelength region A light emitting structure is grown based on AlGaN containing a large amount of polarization may increase in a TM mode in which light emission in a direction parallel to the growth direction of the light emitting structure is dominant compared to a light emitting device emitting light in a blue wavelength region. At this time, light traveling in a lateral direction in the active layer may be reflected by the first reflective layer 250 .

4 to 6 are diagrams showing parts of second to fourth embodiments of semiconductor devices in detail.

4 is a cross-sectional view of a portion of a second embodiment of a semiconductor device. Hereinafter, the second embodiment of the semiconductor device will be described mainly in different parts from the first embodiment of the semiconductor device.

The semiconductor device 200B according to the present embodiment is different from the above-described first embodiment in that the third reflective layer 238 is disposed in the recess region.

The third reflective layer 238 may be formed of at least one material selected from the group consisting of chromium (Cr), aluminum (Al), titanium (Ti), gold (Au), and nickel (Ni) and alloys thereof. . When the third reflective layer 238 is made of aluminum and light in the ultraviolet wavelength range is emitted from the active layer 224, the thickness of the third reflective layer 238 is 50 nanometers or more to reflect light in the ultraviolet wavelength range. It can be enough.

An upper surface of the third reflective layer 238 may be electrically connected to the first electrode layer 242 and a lower surface of the third reflective layer 238 may be electrically connected to the lower reflective layer 265 . Also, the third reflective layer 238 may be electrically separated from the first reflective layer 250 by the second insulating layer 232 .

At this time, the third reflective layer 238 has a portion vertically overlapping with the first reflective layer 250 under the second conductivity type semiconductor layer 226, thereby securing process stability and supporting substrate in the active layer 224. The light output of the light emitting device may be improved by sufficiently reflecting light emitted in the (270) direction.

5 is a cross-sectional view of a portion of a third embodiment of a semiconductor device. Hereinafter, the third embodiment of the semiconductor device will be described mainly in different parts from the second embodiment of the semiconductor device.

5, the height h52 from the bottom surface of the light emitting structure 220 to the top surface of the third reflective layer 238 is greater than the height h51 from the bottom surface of the light emitting structure 220 to the active layer 224. can That is, a portion of the third reflective layer 238, that is, an upper region is disposed at a height corresponding to that of the first conductivity-type semiconductor layer 222, and a lower region extends from the lower portion of the recess region to the second conductivity-type semiconductor layer 226. It may be disposed facing the lower surface. In addition, the middle region of the third reflective layer 238 may be disposed at a height corresponding to the active layer 224 and inclined with the lower surface of the second conductivity type semiconductor layer 226. At this time, the active layer 224 emits light. The light to be reflected may be reflected especially in the middle region of the third reflective layer 238 .

In the semiconductor device 200C according to the present embodiment, the upper surface of the third reflective layer 238 contacts the first electrode layer 242 and is electrically connected to the first conductive semiconductor layer 222, and the lower The surface may contact the lower reflective layer 265 . However, the middle and lower regions of the third reflective layer 238 may be surrounded by the second insulating layer 232 .

6 is a cross-sectional view of a portion of a fourth embodiment of a semiconductor device. Hereinafter, a fourth embodiment of a semiconductor device will be described focusing on different parts from the above-described embodiment of the semiconductor device.

In the semiconductor device 200D of the embodiment, a conductive layer 228 may be disposed under the second conductive semiconductor layer 226 . When the second conductivity-type semiconductor layer 226 is made of AlGaN, AlGaN may not smoothly inject holes due to its low electrical conductivity. However, the conductive layer 228 containing GaN having relatively excellent electrical conductivity is disposed to solve this problem. can solve

The bonding layer 260 passes through the first recess and contacts the first conductivity type semiconductor layer 222. Although not shown, a first conductivity type semiconductor layer 222 is interposed between the bonding layer 260 and the first conductivity type semiconductor layer 222. An electrode layer may be disposed.

The second reflective layer 235 is disposed in the second recess, and the insulating layer 230 extends to the upper surface in addition to the side surface of the second reflective layer 235 and is disposed. The height of the first recess region where the bonding layer 260 contacts the first conductivity-type semiconductor layer 222 is the same as the height of the second recess where the second reflective layer 235 is disposed, but the width of the second recess may be smaller than the width of the first recess.

The insulating layer 230 may be disposed on the upper surface, the side surface, and the bottom surface of the second reflective layer 235, and the bonding layer 260 may be disposed on the lower surface to be electrically connected to the second reflective layer 235. there is.

FIG. 7 is a plan view of a semiconductor device according to a fifth embodiment, and FIG. 8 is a cross-sectional view of the semiconductor device of FIG. 7 in the direction K-K′. Hereinafter, the fifth embodiment of the semiconductor device will be mainly described in terms of differences from the above-described first embodiment.

In the semiconductor device 200E, the second reflective layer 235 is disposed in a low current density region between the first electrode layer 242 and the recesses, and the low current density region is It may be spaced apart from the first electrode layer 242 by a distance r0. In the semiconductor device 200E, the structure including the first electrode layer 242 and the recesses may actually be formed in a larger number, and the number is not limited because it can be designed in consideration of current density. By disposing in consideration of the current density of the first electrode layer 242, it is possible to design a low current density area and dispose the second reflective layer between each low current density area. The second reflective layer 235 may be made of the same material as the third reflective layer 238 of FIGS. 3 to 6 described above.

In FIG. 7 , each of the plurality of first electrode layers 242 is shown in a circular shape, and regions spaced apart from each of the first electrode layers by a distance r0 may be referred to as a 'boundary region', and the current density of the boundary region may be Ii. .

The 'boundary area' may be circular, but may vary according to the shape of the first electrode layer 242, so it is not limited thereto, and the current density Ii in the border area may be 30% to 40% of the above I ₀ , example For example, Ii = I0 × exp (-1).

Also, a region between the plurality of boundary regions may be referred to as a 'low current density region', and the current density of the low current density region may be smaller than Ii described above.

In this embodiment, the second reflective layer 235 is disposed to circumscribe the 'boundary area' around one first electrode layer 242, and the plurality of 'boundary areas' may circumscribe each other or have a spaced distance from each other. Accordingly, when the boundary regions circumscribe each other, the low current density regions may be spaced apart from each other, and when the boundary regions are spaced apart from each other, the low current density regions may be extended and disposed.

In FIG. 8 , a recess is provided from the second conductivity type semiconductor layer 226 to the active layer 224 and a portion of the first conductivity type semiconductor layer 226 to expose the first conductivity type semiconductor layer 222 . There are a plurality of these, which can be divided into a first recess area and a second recess area, and cross sections of the first recess area and the second recess area are, for example, circular, polygonal, elliptical, etc., and are not necessarily limited thereto. don't The second recess area may be disposed around the first recess area.

A first electrode layer 242 is disposed on the first conductive semiconductor layer 222 exposed in the first recess region 1, and the first recess region 1 and the second recess region A second electrode layer 246 may be disposed on the second conductivity type semiconductor layer 226 between the recess region 2 . In addition, the second reflective layer 235 may be inserted and disposed in the second recess region 2, and a portion of the second reflective layer 235 may extend to an area outside the second recess region and be disposed. A portion of the second reflective layer 235 may be disposed at a height corresponding to that of the active layer 224 and a portion of the first conductivity-type semiconductor layer 222 . That is, the top surface of the second reflective layer 235 may be disposed at the same height as the active layer 224 .

When the light emitting structure 220 is based on AlGaN and contains a large amount of aluminum (Al), the current spreading characteristics in the light emitting structure 220 deteriorate. 2 reflective layer 235 is formed. In addition, by changing the path of light emitted in the TM mode from the active layer and traveling in the horizontal direction upward, light absorption in the light emitting structure can be reduced to adjust the beam angle of the semiconductor device and improve light extraction efficiency.

In addition, the first reflective layer 250 is a capping layer that electrically connects the second electrode layer 246 to the second electrode 266 and surrounds and supports the second electrode layer 246 and the reflective layer 235 to ensure stability ( capping layer). In particular, in the edge region of the light emitting structure 220, the second conductivity type semiconductor layer 226 is removed from the active layer 224 and a partial area of the first conductivity type semiconductor layer 222 to be exposed, and the light emitting structure 220 ) may be removed, the first reflective layer 250 may be disposed, and the first reflective layer 250 may extend to a region higher than the active layer 224 and may be disposed in the same manner as in the first embodiment described above. there is.

That is, the edge region of the light emitting structure 220 is exposed by being removed from the second conductivity type semiconductor layer 226 to the active layer 224 and a partial area of the first conductivity type semiconductor layer 222, and the light emitting structure 220 ) may be disposed in the region where the first reflective layer 250 is removed.

In FIG. 8, the area indicated by the line I-I' is the end of the light emitting structure 220 and can be referred to as a separation area of the light emitting structure 220, and the area indicated by the line J-J' is the surface of the light emitting structure 220, that is, the second conductive area. It may be a region in which the upper surface remains without the mold semiconductor layer 226 being removed.

Here, the distance d1 between the line I-I' and the line J-J' may be 3 micrometers to 7 micrometers, for example, 5 micrometers. If the distance between the I-I' line and the J-J' line is less than 3 micrometers, the mesa etch area is narrowed and it may be difficult to form the first reflective layer 250 having a stepped structure. If the distance is greater than 7 micrometers, the process stability However, a problem in that the volume of the active layer 224 decreases may occur.

In the semiconductor device 200E according to the present embodiment, the second reflective layer 235 is provided in the second recess region in the low current density region to reflect light emitted from the active layer 224 and traveling laterally upward. In addition, the first reflective layer 250 extends to a height higher than the active layer 224 at the edge of the light emitting structure 220 and is disposed to reflect light emitted from the active layer 224 and traveling to the edge area in an upward direction. can

The semiconductor device described above is configured as a package and can be used for curing resin, resist, SOD or SOG, for medical purposes such as atopic 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, 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

9 is a view illustrating a package in which semiconductor elements are disposed.

The light emitting device package 300 according to the embodiment includes a package body 310, a first electrode portion 321, a second electrode portion 322, and a light emitting device 200A.

The package body 310 may be made of an insulating material having a cavity, and may include, for example, polypthalamide (PPA) resin or a silicon-based material.

The electrode unit 321 and the second electrode unit 322 are disposed on the package body 310, respectively, and some may be disposed on the bottom surface of the cavity.

The light emitting element 200A may be the light emitting element described above, and may be disposed on the first electrode part 321 and electrically connected to the second electrode part 322 through the wire 330 .

A periphery of the light emitting device 200 and the wire 330 may be filled with air. In the case of a light emitting device that emits ultraviolet rays, if a molding portion made of a silicon-based material is disposed in a region around the light emitting device, defects such as cracks may occur in the molding portion due to energy corresponding to the wavelength of the ultraviolet rays, and thus reliability may be deteriorated.

A phosphor (not shown) may be included around the light emitting element 200A. The phosphor may be YAG-based phosphor, nitride-based phosphor, silicate, or a mixture thereof, but is not limited thereto. A groove is formed on the top of the package body 310 and a cover 370 is disposed on the groove. The cover 370 may be made of a light-transmitting material such as glass, and the package body 310 and the The cover 370 may be coupled, and the adhesive 375 may be, for example, a silicon-based adhesive.

In addition to the shape of the package of FIG. 9 , the semiconductor device may be flip-bonded and used as a package.

The light emitting device includes a laser diode in addition to the above-described light emitting diode, and the structure of the light emitting device according to the embodiment may be applied to a laser diode and other semiconductor devices.

Light emitted from the semiconductor device is a mixture of light in various wavelength regions, and light may be emitted radially from the semiconductor device.

Like a semiconductor device, a laser diode may include a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer having the above structure. In addition, an electro-luminescence phenomenon in which light is emitted from the active layer when a current is passed after bonding a p-type first conductivity type semiconductor and an n-type second conductivity type semiconductor is used. There is a difference in the direction of light and the wavelength band. 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. Therefore, it can be used for optical communication.

The light receiving element may refer to a photodetector that is a kind of transducer that detects light and converts the intensity into an electrical signal. As such photodetectors, photocells (silicon, selenium), photoconductive devices (cadmium sulfide, cadmium selenide), photodiodes (e.g., PDs having peak wavelengths in the visible blind spectral region or true blind spectral region), phototransistors , photomultiplier tube, photoelectric tube (vacuum, gas filled), IR (Infra-Red) detector, etc., but the embodiment is 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. Among them, a pin-type photodetector and a Schottky-type photodetector may be implemented using a nitride semiconductor material.

A photodiode, like a semiconductor device, may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer having the above structure, and is made of a pn junction or pin structure. When a reverse bias is applied to the photodiode, the resistance becomes very high and a minute current flows. However, when light is incident on the photodiode, electrons and holes are generated and current flows.

A photovoltaic cell or solar cell is a type of photodiode and can convert light into electric current using a photoelectric effect. A solar cell, like a semiconductor device, may include a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer having the above structure. When sunlight is incident from the outside, electrons and recesses are generated in the first n-type semiconductor layer and the second p-type semiconductor layer, respectively, and the generated electrons and The recess moves to the n-type electrode and the p-type electrode, respectively, and when the n-type electrode and the p-type electrode are connected to each other, electrons move from the n-type electrode to the p-type electrode, and current flows.

Solar cells can be divided into crystalline solar cells and thin-film solar cells, and thin-film solar cells can be divided into inorganic thin-film solar cells and organic thin-film solar cells.

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, or As, and doped with a p-type or n-type dopant. It may be implemented using a 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 implemented in various configurations through combination or combination with each other, and each component shown in each practical example 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.

200A~200E: semiconductor device 220: light emitting structure
231: first insulating layer 232: second insulating layer
235: second reflective layer 238: third reflective layer
242: first electrode mixture layer 246: second electrode layer
250: first reflective layer 260: bonding layer
265: lower reflective layer 266: second electrode
270: support substrate 300: package

Claims (19)

A first recess region including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, and extending from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer through the active layer. light emitting structures;
a first electrode layer contacting the first conductivity-type semiconductor layer in the first recess region;
a second electrode layer in contact with the second conductivity type semiconductor layer; and
A first reflective layer electrically connected to the second electrode layer and extending from an edge region of the light emitting structure to a region higher than the active layer,
The second electrode layer is electrically connected to a second electrode disposed outside the light emitting structure through the first reflective layer. According to claim 1,
The first reflective layer directly contacts the second conductivity type semiconductor layer in a peripheral region of the second electrode layer. According to claim 1,
The first reflective layer has a layer structure including aluminum, titanium, gold or titanium. According to claim 1,
The edge region of the light emitting structure is removed from the second conductivity-type semiconductor layer to an active layer and a partial region of the first conductivity-type semiconductor layer, and the first reflective layer is disposed in the region from which the light emitting structure is removed. According to claim 4,
A semiconductor device in which a distance between a lower surface of the second conductive semiconductor layer of the light emitting structure and an outermost periphery of the light emitting structure is within 3 to 7 micrometers. According to claim 5,
The second electrode is disposed on the surface of the second conductivity-type semiconductor layer and electrically connected to the first reflective layer;
The semiconductor device further includes a first insulating layer disposed on a surface of the second conductivity type semiconductor layer,
A width of a region where the surface of the second conductivity type semiconductor layer and the first insulating layer contact each other is 5 micrometers to 15 micrometers. According to claim 1,
The semiconductor device of claim 1 , wherein an edge of the surface of the second conductivity-type semiconductor layer and an edge of the second electrode layer are separated from each other by 5 micrometers to 15 micrometers. According to claim 1,
In the edge region of the light emitting structure, the side surface of the light emitting structure is a semiconductor device forming an angle greater than 90 degrees and smaller than 150 degrees with respect to the bottom surface of the light emitting structure. A first recess region including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, extending from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer through the active layer; and a second conductivity type semiconductor layer. a light emitting structure including a recess region and emitting light in an ultraviolet wavelength region;
a first electrode layer contacting the first conductivity-type semiconductor layer in the first recess region;
a second electrode layer in contact with the second conductivity type semiconductor layer;
a first reflective layer electrically connected to the second electrode layer and extending from an edge region of the light emitting structure to a region higher than the active layer; and
A second reflective layer disposed in the second recess area;
The second electrode layer is electrically connected to a second electrode disposed outside the light emitting structure through the first reflective layer. According to claim 9,
The semiconductor device of claim 1 , wherein a height of the first recess region is equal to a height of the second recess region. According to claim 9 or 10,
The semiconductor device of claim 1 , wherein a width of the first recess region is greater than a width of the second recess region. According to claim 9 or 10,
A portion of the first reflective layer overlaps the second reflective layer in a vertical direction. According to claim 12,
The second reflective layer is disposed in a region where the current intensity is 30% to 40% of I ₀ , and the I ₀ is the current intensity in the first conductivity type semiconductor layer contacting the first electrode layer. A first recess region including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, and extending from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer through the active layer; , a light emitting structure that emits light in the ultraviolet wavelength region;
a first electrode layer contacting the first conductivity-type semiconductor layer in the first recess region;
a second electrode layer in contact with the second conductivity type semiconductor layer;
A first reflective layer electrically connected to the second electrode layer and extending from an edge region of the light emitting structure to a region higher than the active layer, and
a third reflective layer at least partially disposed inside the first recess region;
The second electrode layer is electrically connected to a second electrode disposed outside the light emitting structure through the first reflective layer. According to claim 14,
A semiconductor device wherein an upper surface of the third reflective layer is disposed higher than that of the active layer. According to claim 14,
The semiconductor device of claim 1 , wherein a bottom surface of the third reflective layer is disposed below the first recess region and at least partially overlaps the second conductive semiconductor layer in a vertical direction. According to claim 14,
The third reflective layer is electrically connected to the first electrode layer. According to claim 17,
Further comprising a lower reflective layer spaced apart from the lower portion of the light emitting structure,
The third reflective layer is disposed to be spaced apart from the lower reflective layer in the first recess region. According to claim 17,
The semiconductor device further includes a lower reflective layer spaced apart from the lower portion of the light emitting structure, wherein the third reflective layer electrically contacts the lower reflective layer.

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