KR102299745B1 - Semiconductor device - Google Patents

Abstract

The 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 and a semiconductor structure including a plurality of recesses penetrating the active layer and extending to a partial region of the first conductivity-type semiconductor layer; a plurality of first electrodes disposed inside the plurality of recesses and electrically connected to the first conductivity-type semiconductor layer; and a second electrode electrically connected to the second conductivity-type semiconductor layer, wherein the active layer includes a plurality of well layers and a plurality of barrier layers, and the second conductivity-type semiconductor layer has a higher aluminum composition than the well layer. the low 2-1 conductivity type semiconductor layer, and a 2-2 conductivity type semiconductor layer having an aluminum composition higher than that of the well layer, wherein the second electrode is in contact with the 2-1 conductivity type semiconductor layer, and The 2-2 conductivity type semiconductor layer is disposed between the 2-1 conductivity type semiconductor layer and the active layer, and the ratio of the lowest aluminum composition to the highest aluminum composition in the second conductivity type semiconductor layer is 1:5 to 1:90, and a ratio of the maximum horizontal area of the semiconductor structure to the area of the recess is greater than 1:0.16 and less than 1:0.246.

Description

Semiconductor device {SEMICONDUCTOR DEVICE}

The embodiment relates to a semiconductor device.

A semiconductor device including a compound such as GaN or AlGaN has many advantages, such as having a wide and easily adjustable band gap energy, and thus can be used in various ways 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 have developed red, green, and Various colors such as blue and ultraviolet light can be realized, and efficient white light can be realized by using fluorescent materials or combining colors. , safety and environmental friendliness.

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

Therefore, the semiconductor device can replace a light emitting diode backlight, a fluorescent lamp or an incandescent light bulb that replaces a cold cathode fluorescence lamp (CCFL) constituting a transmission module of an optical communication means and a backlight of a liquid crystal display (LCD) display device. The application is expanding to white light emitting diode lighting devices, automobile headlights and traffic lights, and sensors that detect gas or fire. In addition, the application of the semiconductor device may be extended to high-frequency application circuits, other power control devices, and communication modules.

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

However, since the light emitting device emitting light in the ultraviolet wavelength region has a high Al concentration, there is a problem in that the current is not well dispersed in the semiconductor layer. Accordingly, there is a problem in that the light output is weakened and the operating voltage is increased.

The embodiment provides a semiconductor device with improved light output.

In addition, a semiconductor device having a lower operating voltage is provided.

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 semiconductor structure including a plurality of recesses passing through the second conductivity type semiconductor layer and the active layer to a partial region of the first conductivity type semiconductor layer; a plurality of first electrodes disposed inside the plurality of recesses and electrically connected to the first conductivity-type semiconductor layer; and a second electrode electrically connected to the second conductivity-type semiconductor layer, wherein the active layer includes a plurality of well layers and a plurality of barrier layers, and the second conductivity-type semiconductor layer has a higher aluminum composition than the well layer. the low 2-1 conductivity type semiconductor layer, and a 2-2 conductivity type semiconductor layer having a higher aluminum composition than the well layer, wherein the second electrode is in contact with the 2-1 conductivity type semiconductor layer, and The 2-2 conductivity type semiconductor layer is disposed between the 2-1 conductivity type semiconductor layer and the active layer, and the ratio of the lowest aluminum composition to the highest aluminum composition in the second conductivity type semiconductor layer is 1:5 to 1:90, and the ratio of the maximum horizontal area of the semiconductor structure to the area of the recess is greater than 1:0.16 and less than 1:0.246.

A ratio of a first area in which the plurality of first electrodes contact the first conductivity type semiconductor layer to a second area in which the second electrodes contact the 2-1 conductivity type semiconductor layer (first area: second area) area) may be greater than 1:4.87 and less than 1:12.7.

The first area may be greater than 4.9% and less than 8.6% of a maximum cross-sectional area in a horizontal direction of the semiconductor structure, and the horizontal direction may be a direction perpendicular to a thickness direction of the semiconductor structure.

The second area may be greater than 41.9% and less than 62.6% of the maximum cross-sectional area in the horizontal direction of the semiconductor structure.

An area of the plurality of recesses may be greater than 16% and less than 24.6% of a maximum cross-sectional area in a horizontal direction of the semiconductor structure.

The active layer may generate light in the ultraviolet wavelength band.

The thickness ratio of the 2-1 conductivity type semiconductor layer and the 2-2 conductivity type semiconductor layer may be 1:5 to 1:50, and the thickness of the 2-1 conductivity type semiconductor layer may be 1.0 μm to 10 μm. have.

The average aluminum composition of the 2-1 conductivity type semiconductor layer may be 1.0% to 35%.

The diameter of the recess may be 38 μm or more and 60 μm or less, and the diameter of the first electrode may be 24 μm or more and 50 μm or less.

The first conductivity type semiconductor layer may include a 1-2 conductivity type semiconductor layer having a lower composition than the aluminum composition of the active layer, and the first electrode may be disposed on the 1-2 conductivity type semiconductor layer.

A first conductive layer electrically connecting the plurality of first electrodes, a second conductive layer electrically connecting the plurality of second electrodes, and a first insulating layer disposed between the first conductive layer and the second conductive layer and a conductive substrate disposed under the second conductive layer.

According to an embodiment, the light output may be improved.

Also, the operating voltage may be lowered.

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

1 is a conceptual diagram of a semiconductor device according to a first embodiment of the present invention;
Figure 2a is an enlarged view of part A of Figure 1,
Figure 2b is a partial enlarged view of Figure 2a,
3 is a graph of the aluminum composition according to the thickness direction of the semiconductor device according to the first embodiment of the present invention,
4A and 4B are diagrams for explaining a configuration in which light output is improved according to a change in the number of recesses;
5 is a plan view of a semiconductor device according to a first embodiment of the present invention;
6 is a plan view of a semiconductor device according to a second embodiment of the present invention;
7 is a plan view of a semiconductor device according to a third embodiment of the present invention;
8 is a plan view of a semiconductor device according to a fourth embodiment of the present invention;
9 is a graph of measuring light output and power conversion efficiency (Wall-Plug Efficiency) of the semiconductor device according to the first to fourth embodiments;
10 is a conceptual diagram of a semiconductor device according to a fifth embodiment of the present invention;
11 is a plan view of FIG. 10;
12 is a conceptual diagram of a semiconductor device package according to an embodiment of the present invention;
13 is a plan view of a semiconductor device package according to an embodiment of the present invention;
14 is a modification of FIG. 13 .

The present embodiments may be modified in other forms or various embodiments may be 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 a description contradicts or contradicts the matter in another embodiment.

For example, if a specific embodiment describes a feature for configuration A and another embodiment describes a feature for configuration B, the opposite or contradictory description is not explicitly described in an embodiment in which configuration A and configuration B are combined. Unless otherwise indicated, it should be understood as belonging to the scope of the present invention.

In the description of the embodiment, in the case where one element is described as being formed on "on or under" of another element, on (above) or below (on) or under) includes both elements in which two elements are in direct contact with each other or one or more other elements are disposed between the two elements indirectly. In addition, when expressed as "up (up) or down (on or under)", it may include the meaning of not only an upward direction but also a downward direction based on one element.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily implement them.

1 is a conceptual diagram of a semiconductor device according to a first embodiment of the present invention, FIG. 2A is an enlarged view of part A of FIG. 1 , and FIG. 2B is a partially enlarged view of FIG. 2A .

Referring to FIG. 1 , a semiconductor device according to an embodiment includes a semiconductor structure 120 including a first conductivity type semiconductor layer 124 , a second conductivity type semiconductor layer 127 , and an active layer 126 , and a first conductivity type semiconductor layer 126 . It includes a first electrode 142 electrically connected to the type semiconductor layer 124 and a second electrode 146 electrically connected to the second conductivity type semiconductor layer 127 .

The first conductivity type semiconductor layer 124 , the active layer 126 , and the second conductivity type semiconductor layer 127 may be disposed in a first direction (Y direction). Hereinafter, a first direction (Y direction), which is a thickness direction of each layer, is defined as a vertical direction, and a second direction (X direction) perpendicular to the first direction (Y direction) is defined as a horizontal direction.

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

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

The semiconductor structure 120 may include a plurality of recesses 128 that pass through the second conductivity-type semiconductor layer 127 and the active layer 126 to a partial region of the first conductivity-type semiconductor layer 124 . .

The first electrode 142 may be disposed on the upper surface of the recess 128 to be electrically connected to the first conductivity-type semiconductor layer 124 . The second electrode 146 may be disposed under the second conductivity type semiconductor layer 127 .

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. Exemplarily, the first electrode may have a plurality of metal layers (eg, Cr/Al/Ni), and the second electrode may be ITO.

Referring to FIGS. 2A and 2B , when the Al composition of the semiconductor structure 120 is increased, the current diffusion characteristics in the semiconductor structure 120 may be reduced. In addition, the amount of light emitted in the lateral direction of the semiconductor device is increased in the active layer 126 compared to the GaN-based blue light emitting device (TM mode). Such a TM mode may mainly occur in an ultraviolet semiconductor device.

In an ultraviolet light emitting device, current diffusion characteristics may be reduced in a semiconductor structure, and a smooth current injection is required to secure a uniform current density characteristic in the semiconductor structure to secure electrical and optical characteristics and reliability of the semiconductor device. Accordingly, the first electrode 142 may be disposed by forming a relatively large number of recesses 128 compared to a general GaN-based semiconductor structure for smooth current injection. Hereinafter, components for improving current spreading characteristics and current injection characteristics, which are deteriorated when the GaN-based semiconductor structure includes Al, will be described.

The first insulating layer 131 may electrically insulate the first electrode 142 from the active layer 126 and the second conductivity-type semiconductor layer 127 . Also, the first insulating layer 131 may electrically insulate the second electrode 146 and the second conductive layer 150 from the first conductive layer 165 . In addition, the first insulating layer 131 may function to prevent the side surface of the active layer 126 from being oxidized during the process of the semiconductor device.

The first insulating layer 131 _{may be formed by selecting at least one from the group consisting of SiO 2} , SixOy, Si3N4, SixNy, SiOxNy, Al ₂ O ₃ , TiO ₂ , AlN, and the like, but is not limited thereto. The first insulating layer 131 may be formed as a single layer or a multilayer. Exemplarily, the first insulating layer 131 may be a distributed Bragg reflector (DBR) having a multilayer structure including silver Si oxide or a Ti compound. However, the present invention is not limited thereto, and the first insulating layer 131 may include various reflective structures.

When the first insulating layer 131 performs a reflective function, light extraction efficiency may be improved by upwardly reflecting the light L1 emitted from the active layer 126 toward the side. In this case, as the number of recesses 128 increases, light extraction efficiency may be more effective.

The diameter W3 of the first electrode 142 may be 24 μm or more and 50 μm or less. When this range is satisfied, it may be advantageous for current dispersion, and a large number of first electrodes 142 may be disposed. When the diameter W3 of the first electrode 142 is greater than 24 μm, the current injected into the first conductivity type semiconductor layer 124 can be sufficiently secured, and when the diameter W3 of the first electrode 142 is 50 μm or less, the first conductivity type semiconductor layer The number of the plurality of first electrodes 142 disposed in the area of 124 may be sufficiently secured and current dispersion characteristics may be secured.

The diameter W1 of the recess 128 may be 38 μm or more and 60 μm or less. The diameter W1 of the recess 128 is disposed under the second conductivity-type semiconductor layer 127 and may be defined as the widest area in the recess. The diameter W1 of the recess 128 may be the diameter of the recess 128 disposed on the bottom surface of the second conductivity type semiconductor layer 127 .

In forming the first electrode 142 disposed inside the recess 128 when the diameter W1 of the recess 128 is 38 μm or more, the first electrode 142 is of the first conductivity type. It is possible to secure a process margin for securing an area for electrically connecting with the semiconductor layer 124, and to prevent the volume of the active layer 124 from decreasing for disposing the first electrode 142 when it is 60 μm or less. and thus the luminous efficiency may be deteriorated.

The inclination angle θ5 of the recess 128 may be 70 degrees to 90 degrees. When this area range is satisfied, it may be advantageous to form the first electrode 142 on the upper surface, and a large number of recesses 128 may be formed.

When the inclination angle θ5 is less than 70 degrees, the area of the active layer 124 to be removed may increase, but the area in which the first electrode 142 will be disposed may be reduced. Accordingly, current injection characteristics may be deteriorated, and luminous efficiency may be reduced. Accordingly, the area ratio between the first electrode 142 and the second electrode 146 may be adjusted using the inclination angle θ5 of the recess 128 .

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

When the thickness d2 of the first electrode 142 is thinner than the thickness d3 of the first insulating layer 131 , peeling and cracking due to deterioration of the step coverage characteristic occurring when the first conductive layer 165 is disposed problems such as In addition, by having the separation distance d4 from the first insulating layer 131 , a gap-fil characteristic of the second insulating layer 132 may be improved.

The separation distance d4 between the first electrode 142 and the first insulating layer 131 may be 0 μm or more and 4 μm or less. When the separation distance d4 between the first electrode 142 and the first insulating layer 131 is 4 μm or less, the width of the first insulating layer 131 disposed on the upper surface of the recess 128 can be secured, The secured width of the first insulating layer 131 may provide a function of a current blocking layer, thereby securing reliability of the semiconductor device.

The upper surface 143 of the recess 128 has a first region d5 in which the first insulating layer 131 and the first conductivity type semiconductor layer 124 are in contact, and the second insulating layer 132 and the first conductivity type semiconductor layer. It may include a second region d4 in which the layer 124 contacts, and a third region d6 in which the first electrode layer 142 and the first conductivity-type semiconductor layer 124 contact each other. The third region d6 may be the same as the width W3 of the first electrode 142 .

When the first insulating layer 142 and the second insulating layer 132 are made of the same material, the first insulating layer 142 and the second insulating layer 132 may not be separated from each other by physical and/or chemical bonding. may be In this case, the sum of the width of the first region d5 and the width of the second region d4 may be defined as the width of the first region d5 or the width of the second region d4.

When the recess 128 has a diameter W1 and an inclination angle θ5 of the recess 128 , when the width of the first region d5 is widened, the third region d6 is narrowed and the first region d6 is narrowed. When the width of the region d5 is increased, the third region d6 may be widened.

The width of the first region d5 may be 5 μm to 14 μm. When it is 5 μm or more, a process margin for securing the first region d5 can be secured, and since the first region d5 can be secured, the reliability of the semiconductor device can be improved, and the reliability of the semiconductor device can be improved than 14 μm. If it is large, when the recess 128 has a diameter W1 and an inclination angle θ5 of the recess, the width W3 of the first electrode layer 142 may be reduced and electrical characteristics may deteriorate.

Therefore, in order to uniform the current distribution of the semiconductor device and secure the current injection characteristics, the width of the third region d6 may be determined by adjusting the width of the first region d5 and the width of the second region d4. .

In addition, when the total area of the recess 128 is increased, the area in which the second electrode 146 can be disposed may be reduced. Through this complementary relationship, the ratio of the total area of the first electrode 142 to the total area of the second electrode 246 can be determined, and the recess ( The width of 128 and/or the total area of the recess 128 can be freely designed within the above range.

The thickness of the second electrode 146 may be thinner than the thickness of the first insulating layer 131 . Accordingly, the step coverage characteristics of the second conductive layer 150 and the second insulating layer 132 surrounding the second electrode 146 may be secured, and reliability of the semiconductor device may be improved. The second electrode 146 may have a first separation distance S1 from the first insulating layer 131 of 1 μm to 4 μm. When the separation distance is 1 μm or more, a process margin of the process of disposing the second electrode 146 between the first insulating layers 131 can be secured, and thus the electrical characteristics, optical characteristics, and reliability of the semiconductor device are improved. can be When the separation distance is 4 μm or less, the entire area in which the second electrode 146 can be disposed may be secured and the operating voltage characteristics of the semiconductor device may be improved.

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

The second conductive layer 150 may completely surround the second electrode 146 and may be in contact with the side surface and the top surface of the first insulating layer 131 . The second conductive layer 150 is made of a material having good adhesion to the first insulating layer 131 , and at least one material selected from the group consisting of materials such as Cr, Al, Ti, Ni, Au, and these materials. It may be made of an alloy, and may be formed of a single layer or a plurality of layers.

When the second conductive layer 150 is in contact with the side surface and the top surface of the first insulating layer 131 , thermal and electrical reliability of the second electrode 146 may be improved. In addition, it may have a reflection function of reflecting light emitted between the first insulating layer 131 and the second electrode 146 upward.

The second conductive layer 150 may be disposed at a first separation distance S1 between the first insulating layer 131 and the second electrode 146 . The second conductive layer 150 may be in contact with the side surface and the top surface of the second electrode 146 and the side surface and the top surface of the first insulating layer 131 at the first separation distance S1 . In addition, a region in which the second conductive layer 150 and the second conductive semiconductor layer 126 come into contact with each other within the first separation distance S1 to form a Schottky junction may be disposed, and the current by forming the Schottky junction Dispersion can be facilitated. However, the present invention is not limited thereto, and the resistance between the second conductive layer 150 and the second conductivity type semiconductor layer 126 is higher than the resistance between the second electrode 146 and the second conductivity type semiconductor layer 126 . It can be freely placed within this larger configuration.

The second insulating layer 132 may electrically insulate the second electrode 146 and the second conductive layer 150 from the first conductive layer 165 . The first conductive layer 165 may pass through the second insulating layer 132 to be electrically connected to the first electrode 142 . The second insulating layer 132 and the first insulating layer 131 may be formed of the same material or may be formed of different materials.

The first conductivity-type semiconductor layer 124 may be implemented with a compound semiconductor such as III-V group, II-VI group, etc., and the first conductivity-type semiconductor layer 124 is formed on the first conductivity-type semiconductor layer 124 . One dopant may be doped. The first conductivity type semiconductor layer 124 is _{a semiconductor material having a composition formula of In x1} Al _y1 Ga _{1 -x1- y1} N (0≤x1≤1, 0≤y1≤1, 0≤x1+y1≤1), e.g. For example, it may be selected from GaN, AlGaN, InGaN, InAlGaN, and the like. In addition, 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 124 doped with the first dopant may be an n-type semiconductor layer.

The first conductivity type semiconductor layer 124 may include a 1-2 conductivity type semiconductor layer 124b having a relatively low Al composition and a 1-1 conductivity type semiconductor layer 124a having a relatively high Al composition. have. The 1-1 layer 124a may have an Al composition of 60% to 70%, and the 1-2 conductivity type semiconductor layer 124b may have an Al composition of 40% to 50%. In the 1-2 conductivity type semiconductor layer 124b, the Al composition may be lower than the Al composition of the well layer. The 1-2 conductivity type semiconductor layer 124b is disposed adjacent to the active layer 126 . Accordingly, the 1-2 conductivity type semiconductor layer 124b having a relatively low Al composition may be electrically connected to the first electrode 142 , and the 1-2 conductivity type semiconductor layer 124b may be connected to the first electrode 142 . ) can be encountered.

The first electrode 142 may be disposed inside the 1-2 conductivity type semiconductor layer 124b. That is, the recess 128 is preferably formed up to the region of the 1-2 conductivity type semiconductor layer 124b. This is because the 1-1 conductivity type semiconductor layer 124a has a relatively low current diffusion characteristic due to a high Al composition. Accordingly, the first electrode 142 may contact the 1-2 conductivity type semiconductor layer 124b inside the recess 128 to form an ohmic.

The active layer 126 is a layer in which electrons (or holes) injected through the first conductivity type semiconductor layer 124 and holes (or electrons) injected through the second conductivity type semiconductor layer 127 meet. The active layer 126 may transition to a low energy level as electrons and holes recombine, and may generate light having a corresponding wavelength.

The active layer 126 may have 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 126 . The structure is not limited thereto. The active layer may include Al.

The second conductivity-type semiconductor layer 127 is formed on the active layer 126 , and may be implemented as a compound semiconductor such as III-V or II-VI, and is formed on the second conductivity-type semiconductor layer 127 . Dopants may be doped. The second conductivity type semiconductor layer 127 is _{a semiconductor material having a composition formula of In x5} Al _y2 Ga _{1 -x5- y2} N (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 127 doped with the second dopant may be a p-type semiconductor layer.

Referring back to FIG. 1 , the second conductive layer 150 may electrically connect the second electrode 146 and the second electrode pad 166 .

The second electrode 146 may be directly disposed on the second conductivity type semiconductor layer 127 . When the second conductivity type semiconductor layer 127 is AlGaN, hole injection may not be smooth due to low electrical conductivity. Therefore, it is necessary to appropriately adjust the Al composition of the second conductivity type semiconductor layer 127 . This will be described later.

The second conductive layer 150 may be made of at least one material selected from the group consisting of materials such as Cr, Al, Ti, Ni, Au, and alloys thereof, and may be formed of a single layer or a plurality of layers. .

The first conductive layer 165 and the bonding layer 160 may be disposed along the lower surface of the semiconductor structure 120 and the shape of the recess 128 . The first conductive layer 165 may be made of a material having excellent reflectance. For example, the first conductive layer 165 may include aluminum. When the electrode layer 165 includes aluminum, light emitted from the active layer 126 toward the substrate 170 is reflected upward, thereby improving light extraction efficiency. However, the present invention is not limited thereto, and the first conductive layer 165 may provide a function for being electrically connected to the first electrode 142 . The first conductive layer 165 may be disposed without a material having high reflectivity, for example, aluminum and/or silver (Ag). In this case, the first electrode ( 142) and the first conductive layer 165, and between the second conductive semiconductor layer 127 and the first conductive layer 165, a reflective metal layer (not shown) made of a material having high reflectivity may be disposed. have.

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 a semiconductor material. The substrate 170 may be a metal having excellent electrical conductivity and/or thermal conductivity. In this case, heat generated during the operation of the semiconductor device can be quickly discharged to the outside. Also, when the substrate 170 is made of a conductive material, the first electrode 142 may receive an external current through the substrate 170 .

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

A second electrode pad 166 may be disposed in one corner region of the semiconductor device. The second electrode pad 166 may have a concave portion and a convex portion on the upper surface of the second electrode pad 166 because the central portion thereof is depressed. A wire (not shown) may be bonded to the concave portion of the upper surface. Accordingly, the bonding area is increased, so that the second electrode pad 166 and the wire can be more firmly bonded. The second electrode pad 166 may pass through the passivation layer 180 and the first insulating layer 131 to be electrically connected to the second conductive layer 150 .

A passivation layer 180 may be disposed on an upper surface and a side surface of the semiconductor structure 120 . The passivation layer 180 may have a thickness of 200 nm or more to 500 nm or less. When it is 200 nm or more, the electrical and optical reliability of the device can be improved by protecting the device from external moisture or foreign substances, and when it is 500 nm or less, the stress applied to the semiconductor device can be reduced, and the optical and electrical reliability of the semiconductor device is lowered. Alternatively, it is possible to improve the problem that the unit cost of the semiconductor device increases as the process time of the semiconductor device increases.

Concavities and convexities may be formed on the upper surface of the semiconductor structure 120 . Such irregularities may improve extraction efficiency of light emitted from the semiconductor structure 120 . The unevenness may have a different average height depending on the wavelength of ultraviolet rays, and in the case of UV-C, light extraction efficiency may be improved when it has a height of about 300 nm to 800 nm and an average height of about 500 nm to 600 nm.

3 is a graph showing the aluminum composition according to the thickness direction of the semiconductor device according to the first embodiment of the present invention.

The second conductivity-type semiconductor layer 127 of the semiconductor device according to the embodiment includes aluminum in a surface layer in contact with the second electrode 246 . When the GaN thin film is disposed between the second conductivity-type semiconductor layer 127 and the second electrode 246 for ohmic contact, since the GaN thin film absorbs most of the light of the ultraviolet wavelength, there is a problem in that optical properties are deteriorated. Therefore, in the embodiment, it is necessary to adjust the aluminum composition of the second conductivity-type semiconductor layer 127 so that ohmic contact with the second electrode is possible without the GaN thin film.

All of the first conductivity type semiconductor layer 124 , the active layer 126 , and the second conductivity type semiconductor layer 127 according to the embodiment may be AlGaN or AlN. However, it is not necessarily limited to this.

The active layer 126 includes a plurality of well layers 126a and a barrier layer 126b , and an electron blocking layer 129 may be disposed between the active layer 126 and the second conductivity type semiconductor layer 127 .

The electron blocking layer 129 may have an aluminum composition of 50% to 90%. When the aluminum composition of the blocking layer 129 is less than 50%, the height of the energy barrier for blocking electrons may be insufficient, and light emitted from the active layer 126 may be absorbed by the blocking layer 129, and the aluminum composition is 90 %, the electrical characteristics of the semiconductor device may deteriorate.

The electron blocking layer 129 may include a 1-1 section 129a and a 1-2 section 129b. In the 1-1 section 129a, the aluminum composition may be increased as it approaches the blocking layer 129 . The aluminum composition of the 1-1 section 129a may be 80% to 100%. Accordingly, the first-first section 129a of the electron blocking layer 129 may be a portion having the highest Al content in the semiconductor structure. The first-first section 129a may be made of AlGaN or AlN. Alternatively, the 1-1 section 129a may be a superlattice layer in which AlGaN and AlN are alternately disposed.

The thickness of the first-first section 129a may be about 0.1 nm to 4 nm. When the first conductivity-type semiconductor layer 124 is formed of an n-type semiconductor and the second conductivity-type semiconductor layer 127 is formed of a p-type semiconductor, the first conductivity-type semiconductor layer 127 is formed of a second conductivity-type semiconductor In order to effectively block the movement of electrons in the layer 127, the thickness of the first-first section 129a may be 0.1 nm or more.

In addition, in order to secure hole injection efficiency from the second conductivity type semiconductor layer 127 to the active layer 126 , the thickness of the first-first section 129a may be 4 nm or less.

However, the present invention is not limited thereto, and the hole from the second conductivity type semiconductor layer 127 to the active layer 126 rather than the function of blocking electron movement from the first conductivity type semiconductor layer 127 to the second conductivity type semiconductor layer 127 is not limited thereto. The thickness of the 1-1 section 129a may be arranged to be less than 0.1 nm in order to secure the function of injecting the . In addition, the blocking efficiency of electrons moving from the first conductivity type semiconductor layer 124 to the second conductivity type semiconductor layer 127 is secured rather than the hole injection efficiency from the second conductivity type semiconductor layer 127 to the active layer 126 . In order to do this, the thickness of the 1-1 section 129a may exceed 4 nm.

In the embodiment of the present invention, the hole injection efficiency from the second conductivity type semiconductor layer 127 to the active layer 126 and the electrons moving from the first conductivity type semiconductor layer 124 to the second conductivity type semiconductor layer 126 . In order to secure the blocking efficiency, the thickness of section 1-1 (129-a) was arranged to be 0.1 nm or more and 4 nm or less, but the numerical range mentioned when one of the electron blocking function and the hole injection function should be selectively secured may get out of

The first-second section 129b may include an undoped section. The first-second period 129b may serve to prevent the dopant from being dispersed into the active layer 126 .

The second conductivity type semiconductor layer 127 may include a 2-1 conductivity type semiconductor layer 127a and a 2-2 conductivity type semiconductor layer 127b. The 2-1-th conductivity type semiconductor layer 127a may be a surface region in direct contact with the second electrode 146 . The 2-2 conductivity type semiconductor layer 127b may be disposed between the electron blocking layer 129 and the 2-1 conductivity type semiconductor layer 127a.

The aluminum composition of the 2-1th conductivity type semiconductor layer 127a may be lower than the aluminum composition of the well layer 126a. Here, the well layer 126a may be a well layer having the lowest Al composition among the plurality of well layers. If the aluminum composition of the 2-1-th conductivity-type semiconductor layer 127a is higher than that of the well layer 126a, the resistance between the 2-1-th conductivity-type semiconductor layer 127a and the second electrode 146 increases. There is a problem in that sufficient ohmic is not made and current injection efficiency is lowered.

The average aluminum composition of the 2-1-th conductivity type semiconductor layer 127a may be 1% to 35%, or 1% to 10%. If it is greater than 35%, sufficient ohmic may not be achieved with the second electrode, and if the composition is less than 1%, the composition is almost close to the GaN composition, thereby absorbing light.

The thickness of the 2-1-th conductivity type semiconductor layer 127a may be 1 nm to 10 nm. As described above, the 2-1-th conductivity type semiconductor layer 127a may absorb ultraviolet light because the composition of aluminum is low for ohmic reasons. Therefore, it may be advantageous in terms of light output to control the thickness of the 2-1th conductivity type semiconductor layer 127a as thin as possible.

However, when the thickness of the 2-1-th conductivity type semiconductor layer 127a is controlled to be 1 nm or less, since it is too thin, it is difficult to significantly lower the aluminum composition. In addition, when the thickness is thicker than 10 nm, the amount of light absorbed becomes too large, so that the light output efficiency may decrease.

The thickness of the 2-2 conductivity type semiconductor layer 127b may be greater than 10 nm and less than 100 nm. For example, the thickness of the 2-2 conductivity type semiconductor layer 127b may be 25 nm. When the thickness of the second-second conductivity type semiconductor layer 127b is less than 10 nm, resistance increases in the horizontal direction, and thus current injection efficiency may decrease. In addition, when the thickness of the 2-2 conductivity type semiconductor layer 127b is greater than 100 nm, resistance increases in the vertical direction, so that the current injection efficiency may be reduced.

The thickness of the 2-1-th conductivity-type semiconductor layer 127a may be smaller than the thickness of the 2-2-th conductivity type semiconductor layer 127b. A thickness ratio of the 2-1-th conductivity-type semiconductor layer 127a and the 2-2 conductivity-type semiconductor layer 127b may be 1:5 to 1:50. When the thickness ratio is less than 1:5, the thickness of the 2-1-th conductivity type semiconductor layer 127a may be too thick, and thus light output efficiency may be lowered. Also, when the thickness ratio is greater than 1:50, the thickness of the 2-1th conductivity type semiconductor layer 127a may be too thin. Therefore, it may be difficult to lower the aluminum composition to a desired range within a thin thickness range. Accordingly, ohmic reliability may be deteriorated.

The aluminum composition of the 2-2 conductivity type semiconductor layer 127b may be higher than the aluminum composition of the well layer 126a. For example, the aluminum composition of the well layer 126a may be about 30% to 50% to generate ultraviolet light. If the aluminum composition of the 2-2 conductivity type semiconductor layer 127b is lower than the aluminum composition of the well layer 126a, the light extraction efficiency decreases because the 2-2 conductivity type semiconductor layer 127b absorbs light. can

The average aluminum composition of the 2-2 conductivity type semiconductor layer 127b may be greater than 40% and less than 80%. When the aluminum composition of the 2-2 conductivity type semiconductor layer 127b is less than 40%, there is a problem in absorbing light, and when it is greater than 80%, there is a problem in that the current injection efficiency is deteriorated. For example, the average aluminum composition of the 2-2 conductivity type semiconductor layer 127b may be 50%.

The 2-2 conductivity type semiconductor layer 127b may be smaller as the aluminum composition moves away from the active layer 126 in the partial section 127c. In this case, the reduction in aluminum of the 2-1-th conductivity-type semiconductor layer 127a may be greater than the reduction in aluminum of the partial section 127c of the 2-2 conductivity-type semiconductor layer 127b. That is, the Al composition change rate of the 2-1-th conductivity-type semiconductor layer 127a in the thickness direction may be greater than the Al composition change rate of the 2-2-th conductivity-type semiconductor layer 127b.

The thickness of the 2-2 conductivity type semiconductor layer 127b is thicker than that of the 2-1 conductivity type semiconductor layer 127a, but the aluminum composition must be higher than that of the well layer 126a, so the reduction may be relatively gentle. However, since the 2-1-th conductivity type semiconductor layer 127a has a thin thickness and a large change in aluminum composition, the decrease in aluminum composition may be relatively large.

A point where aluminum is lowest in the second conductivity type semiconductor layer 127 may be a point where the 2-1th conductivity type semiconductor layer 127a contacts the second electrode. In this case, the aluminum composition may be 1% to 10%. When the aluminum composition is less than 1%, the amount of light absorption may be increased, and if the aluminum composition is greater than 10%, the ohmic characteristics may be deteriorated.

The lowest point of aluminum in the second conductivity type semiconductor layer 127 may be the point closest to the electron blocking layer 129 . In this case, as described above, the aluminum composition of the electron blocking layer 129 may be 50% to 90%. Accordingly, the maximum aluminum composition of the second conductivity type semiconductor layer 127 may be 50% to 90%.

Accordingly, the aluminum composition change in the thickness direction of the second conductivity type semiconductor layer 127 may be 1% to 90%, or 10% to 90%. In addition, the ratio of the lowest aluminum composition to the highest aluminum composition ratio of the second conductivity type semiconductor layer 127 may be 1:5 to 1:90.

4A and 4B are diagrams for explaining a configuration in which light output is improved according to a change in the number of recesses, FIG. 5 is a plan view of a semiconductor device according to a first embodiment of the present invention, and FIG. 6 is a diagram of the present invention A plan view of a semiconductor device according to a second embodiment, FIG. 7 is a plan view of a semiconductor device according to a third embodiment of the present invention, FIG. 8 is a plan view of a semiconductor device according to a fourth embodiment of the present invention, and FIG. 9 are graphs in which the optical output and WPE of the semiconductor devices according to the first to fourth embodiments are measured.

Referring to FIG. 4A , when the GaN-based semiconductor structure 120 emits ultraviolet light, it may contain aluminum, and when the aluminum composition of the semiconductor structure 120 increases, the current dissipation characteristic in the semiconductor structure 120 decreases. can be In addition, when the active layer 126 contains Al and emits ultraviolet light, the amount of light emitted laterally from the active layer 126 is increased compared to the GaN-based blue light emitting device (TM mode). Such a TM mode may mainly occur in an ultraviolet semiconductor device.

The ultraviolet semiconductor device has inferior current dissipation characteristics compared to the blue GaN-based semiconductor device. Therefore, it is necessary to dispose a relatively large number of first electrodes 142 in the ultraviolet semiconductor device compared to the blue GaN-based semiconductor device.

If the composition of aluminum increases, the current dissipation characteristic may deteriorate. Referring to FIG. 4A , the current is distributed only at a point adjacent to each of the first electrodes 142 , and the current density may be sharply lowered at a point farther away. Accordingly, the effective light emitting area P2 may be narrowed.

The effective light emitting region P2 may be defined as a region up to the boundary point where the current density is 40% or less based on the current density at the center of the first electrode 142 having the highest current density. For example, the effective light emitting area P2 may be adjusted according to the level of the injection current and the Al composition within a range of 40 μm from the center of the recess 128 .

Since the low current density region P3 has a low current density, the amount of light emitted may be less than that of the effective light emitting region P2 . Accordingly, the light output may be improved by further disposing the first electrode 142 in the low current density region P3 having a low current density or using a reflective structure.

In general, in the case of a GaN-based semiconductor device emitting blue light, it is preferable to minimize the area of the recess 128 and the first electrode 142 because the current dispersion characteristic is relatively excellent. This is because as the area of the recess 128 and the first electrode 142 increases, the area of the active layer 126 decreases. However, in the case of the embodiment, since the aluminum composition is high and the current dissipation characteristic is relatively low, the area and/or the number of the first electrodes 142 is increased even at the expense of the area of the active layer 126 to increase the low current density region P3. It may be desirable to reduce , or arrange a reflective structure in the low current density region P3.

Referring to FIG. 4B , when the number of the recesses 128 is increased to 48, the recesses 128 may be disposed in a zigzag manner instead of being disposed in a straight line in the horizontal and vertical directions. In this case, since the area of the low current density region P3 can be narrowed, most of the active layer 126 can participate in light emission.

5 to 8 , when the number of recesses is increased to 79, 96, 116, and 137, respectively, it can be seen that the low current density region (a dotted circle region) is further reduced.

Table 1 below shows the total area (ISO area) of the semiconductor structures of Examples 1 to 4, the area of the p-ohmic electrode (the second area), the area of the n-ohmic electrode (the first area), the area ratio, and the number of recesses was measured.

The semiconductor structure area (ISO area) may be a horizontal maximum cross-sectional area including the recess area.

The area of the first electrode may be an area of the n-ohmic electrode that increases as the number of recesses 128 increases based on 100% of the area of the semiconductor structure.

The area of the second electrode may be an area of the p-ohmic electrode that decreases as the number of recesses 128 increases based on 100% of the area of the semiconductor structure.

In Table 2 below, the semiconductor structure area (ISO area), the recess area, the area of the second conductivity type semiconductor layer, the area of the first conductive layer, and the area of the second electrode pad of Examples 1 to 4 were measured.

The recess area is a total area of the recess that increases as the number of recesses increases based on 100% of the area of the semiconductor structure. Here, the area of each recess may be the maximum area in the thickness direction.

The area of the second conductivity type semiconductor layer is a total area of the second conductivity type semiconductor layer that decreases as the number of recesses increases based on 100% of the area of the semiconductor structure.

The area of the first conductive layer is a total area of the first conductive layer that decreases as the number of recesses increases based on 100% of the semiconductor structure.

The second electrode pad was designed to have a constant area irrespective of the number of recesses based on 100% of the semiconductor structure.

Total area of semiconductor structure [%] 1st electrode area [%] second electrode
area[%] 1st electrode: 2nd electrode
area ratio recess
Count Example 1 100 4.9 62.6 1:12.7 79 Example 2 100 6.0 56.5 1:9.41 96 Example 3 100 7.3 49.4 1:6.76 116 Example 4 100 8.6 41.9 1:4.87 137

Total area of semiconductor structure [%] recess
area[%] Second conductive type semiconductor layer area [%] 1st conductive layer
area[%] Second electrode pad area [%] Example 1 100 16 84.0 72.4 4.4 Example 2 100 18.5 81.5 67.1 4.4 Example 3 100 21.5 78.5 60.9 4.4 Example 4 100 24.6 75.4 54.3 4.4

Referring to Examples 1 to 4, it can be seen that as the number of the recesses 128 increases, the areas of the active layer and the second electrode decrease, and the total area of the recess 128 and the total area of the first electrode gradually increase. have.

In Examples 1 to 4, the size of the semiconductor device, the size of the recess, and the size of the first electrode were the same. Exemplarily, the diameter of the recess 128 was manufactured to be the same as 56 μm, and the diameter of the first electrode was manufactured to be the same as 42 μm.

A first area of the plurality of first electrodes 142 in contact with the first conductivity-type semiconductor layer 124 may be 4.9% or more and 8.6% or less of the maximum horizontal cross-sectional area of the semiconductor structure 120 .

When the first area of the plurality of first electrodes 142 is 4.9% or more, sufficient current injection characteristics can be secured, so that the light output can be secured. It is possible to improve operating voltage characteristics and light output.

In addition, the total area of the plurality of recesses 128 may be 16% or more and 24.6% or less of the maximum horizontal cross-sectional area of the semiconductor structure 120 . If the total area of the recess 128 does not satisfy the above condition, it is difficult to control the total area of the first electrode 142 to be 4.9% or more and 8.6% or less. When the semiconductor structure 120 is configured based on AlGaN, since the resistance of the semiconductor structure 120 is high, the current injection characteristics injected into the semiconductor structure 120 from the outside and the current diffusion characteristics within the semiconductor structure 120 are It may be lower than that of the GaN-based semiconductor structure 120 . Therefore, when the total area of the recess is 16% or more of the maximum cross-sectional area in the horizontal direction of the semiconductor structure 120, electrical characteristics by current injection and current diffusion characteristics can be secured, and when the total area of the recess is 24.6% or less, the active layer 126 emitting light ) to secure the optical properties such as light output.

A second area of the second electrode 246 in contact with the second conductivity-type semiconductor layer 127 may be 41.9% or more and 62.6% or less of the maximum horizontal cross-sectional area of the semiconductor structure 120 . The second area may be a total area of the second electrode 246 in contact with the second conductivity-type semiconductor layer 127 .

The second area for securing the operating voltage characteristics of the semiconductor device and for securing the injection efficiency of holes for injecting holes into the semiconductor structure 120 may be 42% or more of the maximum horizontal cross-sectional area of the semiconductor structure 120 . . In addition, in order to secure a balance between electron injection efficiency and hole injection efficiency and electron injection efficiency to be injected into the semiconductor structure 120 , and to secure optical and electrical characteristics of the semiconductor device, the second area is the semiconductor It may be 62.6% or less of the maximum horizontal cross-sectional area of the structure 120 .

According to an embodiment, since the surface of the second conductivity-type semiconductor layer in contact with the second electrode includes aluminum, current dissipation efficiency may be relatively reduced. Therefore, it is necessary to increase the contact area of the second electrode to improve the current dissipation efficiency.

Referring to FIG. 9 , based on 100% of the light output of the first embodiment (#1) in which the number of recesses 128 is 79, the second embodiment (#2) in which the number of recesses 128 is 96 ), the light output was improved by 4% compared to the first embodiment. In addition, in the third embodiment (#3), in which the number of recesses is increased to 116, the light output is improved by 3% compared to the first embodiment. However, in the case of the fourth embodiment (#4) in which the number of recesses is increased to 137, it can be seen that the light output is rather decreased than in the third embodiment.

In addition, it can be seen that the power conversion efficiency (Wall-Plug Efficiency) also exhibits the same tendency as the light output. The power conversion efficiency may be output power/input power. Illustratively, the horizontal dotted line may be a desired WPE reference, but is not limited thereto.

The first area and the second area have an inverse relationship. That is, when the number of recesses is increased to increase the number of the first electrodes, the area of the second electrode is decreased. In the case of the first and fourth embodiments, it can be seen that the first area or the second area is excessively reduced, and as a result, the light output is lowered.

Referring to FIG. 9 , it can be seen that when the number of recesses is greater than 79 and smaller than 137, a relatively high light output and power conversion efficiency can be obtained.

Accordingly, the ratio (first area: second area) of the first area in which the plurality of first electrodes contact the first conductivity type semiconductor layer to the second area in which the second electrodes contact the second conductivity type semiconductor layer is 1 It can be controlled larger than :4.87 and smaller than 1:12.7.

When the area ratio is greater than 1:4.87, the second area to the first area may be sufficiently secured. Accordingly, the current injection characteristic by the second electrode is improved to ensure a balance between electrons and holes injected into the active layer 126 . In addition, it is possible to improve the current injection characteristics of the semiconductor device.

Illustratively, in the case of Example 4, since the second area is only about 41.9%, the balance between electrons and holes injected into the active layer 126 may not be secured, and current injection characteristics of the semiconductor device may be deteriorated. As a result, the light output of the semiconductor device may decrease.

In order to secure the first area to the second area, the area ratio may be adjusted to be less than 1:12.7. When the area ratio is adjusted to be less than 1:12.7, the current injection characteristic by the first electrode can be improved and the balance between electrons and holes injected into the active layer 126 can be secured, thereby improving the current injection characteristic of the semiconductor device. Exemplarily, in the case of Example 1, since the first area is only about 4.9%, the current injection efficiency may be reduced.

Also, a ratio between the maximum horizontal area of the semiconductor structure and the area of the recess may be greater than 1:0.16 and less than 1:0.246. When the area ratio is greater than 1:0.16, a sufficient first area may be secured to improve current injection characteristics by the first electrode. In addition, when the area ratio is smaller than 1:0.246, the second area may be secured to improve the current injection characteristics.

10 is a conceptual diagram of a semiconductor device according to a fifth embodiment of the present invention, and FIG. 11 is a plan view of FIG. 10 .

Referring to FIG. 10 , the above-described configuration may be applied to the light emitting structure 120 as it is. The plurality of recesses 128 may penetrate through the second conductivity type semiconductor layer 127 and the active layer 126 to a partial region of the first conductivity type semiconductor layer 124 .

The first electrode 142 may be disposed on the upper surface of the recess 128 to be electrically connected to the first conductivity-type semiconductor layer 124 . The second electrode 146 may be formed under the second conductivity type semiconductor layer 127 . The second electrode 146 may be in contact with and electrically connected to the 2-1-th conductivity type semiconductor layer 127a.

Since the 2-1-th conductivity type semiconductor layer 127a in contact with the second electrode 146 has an average aluminum composition of 10% to 35%, ohmic connection may be easy. In addition, since the 2-1-th conductivity type semiconductor layer 127a has a thickness greater than 1 nm and less than 10 nm, light absorption may be small.

When the second electrode 146 is made of a metal oxide such as ITO, the 2-1-th conductivity type semiconductor layer 127a may be in contact with oxygen. Accordingly, aluminum disposed on the surface of the 2-1-th conductivity type semiconductor layer 127a may react with oxygen to form aluminum oxide. In addition, a nitride such as NO or _{an oxide of Ga 2} O ₃ may be further formed.

A second electrode pad 166 may be disposed in one corner region of the semiconductor device. The second electrode pad 166 may have a concave portion and a convex portion on the upper surface of the second electrode pad 166 because the central portion thereof is depressed. A wire (not shown) may be bonded to the concave portion of the upper surface. Accordingly, the bonding area is increased, so that the second electrode pad 166 and the wire can be more firmly bonded.

The first insulating layer 131 may electrically insulate the first electrode 142 from the active layer 126 and the second conductivity-type semiconductor layer 127 . Also, the first insulating layer 131 may electrically insulate the second electrode 146 and the second conductive layer 150 from the first conductive layer 165 .

The first insulating layer 131 may be formed by selecting at least one selected from the group consisting _{of SiO 2} , SixOy, Si ₃ N ₄ , Si _x N _y , SiO _x N _y , Al ₂ O ₃ , TiO _{2 , AlN, and the like.} However, the present invention is not limited thereto. The first insulating layer 131 may be formed as a single layer or a multilayer. Exemplarily, the first insulating layer 131 may be a distributed Bragg reflector (DBR) having a multilayer structure including silver Si oxide or a Ti compound. However, the present invention is not limited thereto, and the first insulating layer 131 may include various reflective structures.

When the first insulating layer 131 performs an insulating function, light emitted from the active layer 126 toward the side may be upwardly reflected to improve light extraction efficiency. As will be described later, in the ultraviolet semiconductor device, as the number of recesses 128 increases, light extraction efficiency may be more effective.

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

The second conductive layer 150 completely surrounds the second electrode 146 and may be in contact with the side surface and the top surface of the first insulating layer 131 . The second conductive layer 150 is made of a material having good adhesion to the first insulating layer 131 , and at least one material selected from the group consisting of materials such as Cr, Al, Ti, Ni, Au, and these materials. It may be made of an alloy of , and may be made of a single layer or a plurality of layers.

When the second conductive layer 150 is in contact with the side surface and the top surface of the first insulating layer 131 , thermal and electrical reliability of the second electrode 146 may be improved. In addition, it may have a reflection function of reflecting light emitted between the first insulating layer 131 and the second electrode 146 upward.

The second insulating layer 132 may electrically insulate the second electrode 146 and the second conductive layer 150 from the first conductive layer 165 . The first conductive layer 165 may pass through the second insulating layer 132 to be electrically connected to the first electrode 142 .

The first conductive layer 165 and the bonding layer 160 may be disposed along the lower surface of the light emitting structure 120 and the shape of the recess 128 . The first conductive layer 165 may be made of a material having excellent reflectance. For example, the first conductive layer 165 may include aluminum. When the first conductive layer 165 includes aluminum, light emitted from the active layer 126 may be reflected upward to improve light extraction efficiency.

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 a semiconductor material. The substrate 170 may be a metal having excellent electrical conductivity and/or thermal conductivity. In this case, heat generated during the operation of the semiconductor device can be quickly discharged 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.

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

The semiconductor device may include a side reflector Z1 disposed at an edge thereof. The side reflector Z1 may be formed in which the second conductive layer 150 , the first conductive layer 165 , and the substrate 170 protrude in the thickness direction (the Y-axis direction). Referring to FIG. 11 , the side reflective part Z1 may be disposed along the edge of the semiconductor device to surround the light emitting structure.

The second conductive layer 150 of the side reflection part Z1 may protrude higher than the active layer 126 to upwardly reflect light emitted from the active layer 126 . Accordingly, even without forming a separate reflective layer, light emitted in the horizontal direction (X-axis direction) due to the TM mode from the outermost layer may be upwardly reflected.

The inclination angle of the side reflector Z1 may be greater than 90 degrees and less than 145 degrees. The inclination angle may be an angle formed by the second conductive layer 150 with a horizontal plane (XZ plane). When the angle is smaller than 90 degrees or larger than 145 degrees, the efficiency of reflecting light moving toward the side upward may be reduced.

12 is a conceptual diagram of a semiconductor device package according to an embodiment of the present invention, FIG. 13 is a plan view of a semiconductor device package according to an embodiment of the present invention, and FIG. 14 is a modification of FIG. 13 .

Referring to FIG. 12 , the semiconductor device package includes a body 2 in which a groove 3 is formed, a semiconductor device 1 disposed in the body 2 , and a semiconductor device 1 disposed in the body 2 to electrically communicate with the semiconductor device 1 . It may include a pair of lead frames (5a, 5b) connected. The semiconductor device 1 may include all of the above-described configurations.

The body 2 may include a material or a coating layer that reflects ultraviolet light. The body 2 may be formed by laminating a plurality of layers 2a, 2b, 2c, 2d, and 2e. The plurality of layers 2a, 2b, 2c, 2d, and 2e may be made of the same material or may include different materials.

The groove 3 may be formed to become wider as it moves away from the semiconductor device, and a step 3a may be formed on the inclined surface.

The light transmitting layer 4 may cover the groove 3 . The light transmitting layer 4 may be made of a glass material, but is not limited thereto. The light-transmitting layer 4 is not particularly limited as long as it is a material that can transmit ultraviolet light effectively. The interior of the groove 3 may be an empty space.

Referring to FIG. 13 , the semiconductor device 10 may be disposed on the first leadframe 5a and may be connected to the second leadframe 5b by wires. In this case, the second leadframe 5b may be disposed to surround the side surface of the first leadframe.

Referring to FIG. 14 , in the semiconductor device package, a plurality of semiconductor devices 10a, 10b, 10c, and 10d may be disposed. In this case, the leadframe may include first to fifth leadframes 5a, 5b, 5c, 5d, and 5e.

The first semiconductor device 10a may be disposed on the first leadframe 5a and may be connected to the second leadframe 5b with a wire. The second semiconductor device 10b may be disposed on the second leadframe 5b and may be connected to the third leadframe 5c with a wire. The third semiconductor device 10c may be disposed on the third leadframe 5c and may be connected to the fourth leadframe 5d with a wire. The fourth semiconductor device 10d may be disposed on the fourth leadframe 5d and may be connected to the fifth leadframe 5e with a wire.

The semiconductor device may be applied to various types of light source devices. For example, the light source device may be a concept including a lighting device, a display device, and a vehicle lamp. That is, the semiconductor element may be applied to various electronic devices that are disposed in a case and provide light.

The lighting device may include a light source module including a substrate and a semiconductor device according to an embodiment, a heat dissipating unit for dissipating heat from the light source module, and a power supply unit for processing or converting an electrical signal provided from the outside and providing it to the light source module. In addition, the lighting device may include a lamp, a head lamp, or a street lamp.

The display device may include a bottom cover, a reflector, a light emitting module, a light guide plate, an optical sheet, a display panel, an image signal output circuit, and a color filter. The bottom cover, the reflector, the light emitting module, the light guide plate, and the optical sheet may constitute a backlight unit.

The reflector is disposed on the bottom cover, and the light emitting module may emit light. The light guide plate may be disposed in front of the reflection plate to guide the light emitted from the light emitting module to the front, and the optical sheet may include a prism sheet and the like, and may be disposed in front of the light guide plate. The display panel may be disposed in front of the optical sheet, the image signal output circuit may supply an image signal to the display panel, and the color filter may be disposed in front of the display panel.

When used as a backlight unit of a display device, the semiconductor device may be used as an edge type backlight unit or may be used as a direct type backlight unit.

The semiconductor device may be a laser diode in addition to the light emitting diode described above.

The laser diode may include a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer having the above-described structure in the same manner as the light emitting device. And, it uses the electro-lminescence phenomenon in which light is emitted when a current flows after bonding a p-type first conductivity type semiconductor and an n-type second conductivity type semiconductor. There is a difference in the direction and phase of light. That is, the laser diode uses a phenomenon called stimulated emission and constructive interference, so that light having one specific wavelength (monochromatic beam) can be emitted with the same phase and in the same direction. Therefore, it can be used for optical communication, medical equipment, and semiconductor processing equipment.

As the light receiving element, a photodetector, which is a kind of transducer that detects light and converts its intensity into an electrical signal, may be exemplified. As such a photodetector, a photovoltaic cell (silicon, selenium), an optical output device (cadmium sulfide, cadmium selenide), a photodiode (for example, a PD having a peak wavelength in a visible blind spectral region or a true blind spectral region), a photo A transistor, a photomultiplier tube, a phototube (vacuum, gas-filled), an IR (Infra-Red) detector, etc., but the embodiment is not limited thereto.

In addition, a semiconductor device such as a photodetector may be generally manufactured using a direct bandgap semiconductor having excellent light conversion efficiency. Alternatively, the photodetector has various structures, and the most common structures include a pin-type photodetector using a pn junction, a Schottky-type photodetector using a Schottky junction, and a Metal Semiconductor Metal (MSM) photodetector. have.

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 in the same way as the light emitting device, and has a pn junction or pin structure. The photodiode operates by applying a reverse bias or zero bias, and when light is incident on the photodiode, electrons and holes are generated and a current flows. In this case, the magnitude 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 may convert light into electric current. The solar cell may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer having the above-described structure in the same manner as the light emitting device.

In addition, it may be used as a rectifier of an electronic circuit through the rectification characteristic of a general diode using a p-n junction, and may be applied to an oscillation circuit by being applied to a very high frequency circuit.

In addition, the above-described semiconductor device is not necessarily implemented only 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 formed using a p-type or n-type dopant. It may be implemented using a doped semiconductor material or an intrinsic semiconductor material.

Although the embodiment has been described above, it is only an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are not exemplified above in a range that does not depart from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

Claims (11)

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 semiconductor structure including a plurality of recesses passing through the second conductivity-type semiconductor layer and the active layer to a partial region of the first conductivity-type semiconductor layer;
a plurality of first electrodes disposed inside the plurality of recesses and electrically connected to the first conductivity-type semiconductor layer; and
a second electrode electrically connected to the second conductivity-type semiconductor layer;
the active layer includes a plurality of well layers and a plurality of barrier layers;
The second conductivity type semiconductor layer includes a 2-1 conductivity type semiconductor layer having an aluminum composition lower than that of the well layer, and a 2-2 conductivity type semiconductor layer having an aluminum composition higher than that of the well layer,
The second electrode is in contact with the 2-1 conductivity type semiconductor layer, the 2-2 conductivity type semiconductor layer is disposed between the 2-1 conductivity type semiconductor layer and the active layer,
The ratio of the lowest aluminum composition to the highest aluminum composition in the second conductivity-type semiconductor layer is 1:5 to 1:90,
A ratio of the maximum horizontal area of the semiconductor structure to the area of the recess is greater than 1:0.16 and less than 1:0.246.
According to claim 1,
A ratio of a first area in which the plurality of first electrodes contact the first conductivity type semiconductor layer to a second area in which the second electrodes contact the 2-1 conductivity type semiconductor layer (first area: second area area) is greater than 1:4.87 and less than 1:12.7.
3. The method of claim 2,
The first area is greater than 4.9% and less than 8.6% of a maximum cross-sectional area in a horizontal direction of the semiconductor structure, and the horizontal direction is a direction perpendicular to a thickness direction of the semiconductor structure.
3. The method of claim 2,
The second area is greater than 41.9% and smaller than 62.6% of the maximum horizontal cross-sectional area of the semiconductor structure.
According to claim 1,
The active layer is a semiconductor device that generates light in the ultraviolet wavelength band.
According to claim 1,
The thickness ratio of the 2-1 conductivity type semiconductor layer and the 2-2 conductivity type semiconductor layer is 1:5 to 1:50,
The thickness of the 2-1 conductive semiconductor layer is in a range of 1.0 μm to 10 μm.
According to claim 1,
The average aluminum composition of the 2-1 conductivity-type semiconductor layer is 1.0% to 35% of the semiconductor device.
According to claim 1,
The diameter of the recess is 38 μm or more and 60 μm or less.
According to claim 1,
The first electrode has a diameter of 24 μm or more and 50 μm or less.
According to claim 1,
The first conductivity type semiconductor layer includes a 1-2 conductivity type semiconductor layer having a lower composition than the aluminum composition of the active layer,
The first electrode is a semiconductor device disposed on the 1-2 conductivity type semiconductor layer.
According to claim 1,
a first conductive layer electrically connecting the plurality of first electrodes;
a second conductive layer electrically connecting the plurality of second electrodes;
a first insulating layer disposed between the first conductive layer and the second conductive layer; and
and a conductive substrate disposed under the second conductive layer.

Images