KR102632215B1 - Semiconductor device and semiconductor device package including the same - Google Patents

Abstract

An embodiment includes a light emitting structure including 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 first electrode electrically connected to the first conductive semiconductor layer; and a second electrode electrically connected to the second conductive semiconductor layer, wherein the second conductive semiconductor layer includes a first surface on which the second electrode is disposed, and the second conductive semiconductor layer includes The ratio (W2:W1) of the second shortest distance (W2) from the first surface to the second point and the first shortest distance (W1) from the first surface to the first point is 1:1.25 to 1:100. The first point is a point in the active layer that has the same composition as the aluminum composition of the well layer closest to the second conductivity type semiconductor layer, and the second point is a point in which the aluminum composition and the dopant composition of the second conductivity type semiconductor layer are Disclosed is a semiconductor device at the point where it becomes identical and a semiconductor device package including the same.

Description

Semiconductor device and semiconductor device package including the same {SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE PACKAGE INCLUDING THE SAME}

The embodiment relates to a semiconductor device and a semiconductor device package including the same.

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

In particular, light-emitting devices such as light emitting diodes and laser diodes using group 3-5 or group 2-6 compound semiconductor materials have been developed into red, green, and green colors through the development of thin film growth technology and device materials. Various colors such as blue and ultraviolet rays can be realized, and efficient white light can also be realized by using fluorescent materials or combining colors. Compared to existing light sources such as fluorescent lights and incandescent lights, it has low power consumption, semi-permanent lifespan, and fast response speed. , has the advantages of 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, the development of device materials absorbs light in various wavelength ranges to generate photocurrent. By doing so, light of various wavelengths, from gamma rays to radio wavelengths, can be used. In addition, it has the advantages of fast response speed, safety, environmental friendliness, and easy control of device materials, so it can be easily used in power control, ultra-high frequency circuits, or communication modules.

Therefore, semiconductor devices can replace the transmission module of optical communication means, the light emitting diode backlight that replaces the cold cathode fluorescence lamp (CCFL) that constitutes the backlight of LCD (Liquid Crystal Display) display devices, and fluorescent or incandescent light bulbs. Applications are expanding to include white light-emitting diode lighting devices, automobile headlights and traffic lights, and sensors that detect gas or fire. In addition, the applications of semiconductor devices can be expanded to high-frequency application circuits, other power control devices, and communication modules.

In particular, light-emitting devices that emit light in the ultraviolet wavelength range have a curing or sterilizing effect and can be used for curing, medical purposes, and sterilization.

Recently, research on ultraviolet light-emitting devices has been active, but there are still problems with the ultraviolet light-emitting devices being difficult to implement vertically, and there is a problem of crystallinity deteriorating during the process of separating the substrate.

The embodiment provides a vertical ultraviolet light emitting device.

Additionally, a light emitting device with improved light output is provided.

The problem to be solved in the embodiment is not limited to this, and it will also include means of solving the problem described below and purposes and effects that can be understood from the embodiment.

A semiconductor device according to an embodiment of the present invention emits light including 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. structure; a first electrode electrically connected to the first conductive semiconductor layer; and a second electrode electrically connected to the second conductive semiconductor layer, wherein the second conductive semiconductor layer includes a first surface on which the second electrode is disposed, and the second conductive semiconductor layer includes The ratio (W2:W1) of the second shortest distance (W2) from the first surface to the second point and the first shortest distance (W1) from the first surface to the first point is 1:1.25 to 1:100. The first point is a point in the active layer that has the same composition as the aluminum composition of the well layer closest to the second conductivity type semiconductor layer, and the second point is a point in which the aluminum composition and the dopant composition of the second conductivity type semiconductor layer are This may be the point where they become the same.

According to the embodiment, a vertical ultraviolet light-emitting device can be manufactured.

Additionally, light output can be improved.

The various and beneficial advantages and effects of the present invention are not limited to the above-described content, and may be more easily understood through description of specific embodiments of the present invention.

1 is a conceptual diagram of a light-emitting structure according to an embodiment of the present invention,
Figure 2 is a graph showing the aluminum composition ratio of a light emitting structure according to an embodiment of the present invention,
3 is a conceptual diagram of a semiconductor device according to an embodiment of the present invention,
4A and 4B are plan views of a semiconductor device according to an embodiment of the present invention;
Figure 5 is a SIMS graph of the light emitting structure according to the first embodiment of the present invention,
Figure 6 is a partial enlarged view of Figure 5,
Figure 7 is a SIMS graph of the light emitting structure according to the second embodiment of the present invention,
Figure 8 is a partial enlarged view of Figure 7,
Figure 9 is a SIMS graph of the light emitting structure according to the third embodiment of the present invention,
Figure 10 is a partial enlarged view of Figure 9;
Figure 11 is a conceptual diagram of a light emitting device package according to an embodiment of the present invention.

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 embodiment described below.

Even if matters described in a specific embodiment are not explained in other embodiments, they may be understood as descriptions related to other embodiments, as long as there is no explanation contrary to or contradictory to the matter in the other embodiments.

For example, if a feature for configuration A is described in a specific embodiment and a feature for configuration B is described in another embodiment, the description is contrary or contradictory even if an embodiment in which configuration A and configuration B are combined is not explicitly described. Unless otherwise stated, it should be understood as falling within the scope of the rights of the present invention.

In the description of the embodiment, when an element is described as being formed “on or under” another element, or under) includes both elements that are in direct contact with each other or one or more other elements that are formed (indirectly) between the two elements. Additionally, when expressed as "on or under," it can include not only the upward direction but also the downward direction based on one element.

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

The light emitting structure according to an embodiment of the present invention can output light in the ultraviolet wavelength range. For example, the light emitting structure may output light in the near-ultraviolet wavelength range (UV-A), light in the far-ultraviolet wavelength range (UV-B), or light in the deep ultraviolet wavelength range (UV-C). Can be printed. The wavelength range may be determined by the Al composition ratio of the light emitting structure 120.

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

Figure 1 is a conceptual diagram of a light emitting structure according to an embodiment of the present invention, and Figure 2 is a graph showing the aluminum composition ratio of the light emitting structure according to an embodiment of the present invention.

Referring to FIG. 1, the semiconductor device according to the embodiment includes a first conductive semiconductor layer 124, a second conductive semiconductor layer 127, and a first conductive semiconductor layer 124 and a second conductive semiconductor layer. It includes a light emitting structure 120 including an active layer 126 disposed between (127).

The first conductive semiconductor layer 124 may be implemented with a compound semiconductor such as group III-V or group II-VI, and may be doped with a first dopant. The first conductive semiconductor layer 124 is made of a semiconductor material with a composition formula of Inx1Aly1Ga1-x1-y1N (0≤x1≤1, 0≤y1≤1, 0≤x1+y1≤1), for example, GaN, AlGaN, It can be selected from InGaN, InAlGaN, etc. And, 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 conductive semiconductor layer 124 doped with the first dopant may be an n-type semiconductor layer.

The active layer 126 is disposed between the first conductive semiconductor layer 124 and the second conductive semiconductor layer 127. The active layer 126 is a layer where electrons (or holes) injected through the first conductive semiconductor layer 124 and holes (or electrons) injected through the second conductive semiconductor layer 127 meet. The active layer 126 transitions to a low energy level as electrons and holes recombine, and can generate light having an ultraviolet 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 to this.

The second conductive semiconductor layer 127 is formed on the active layer 126 and may be implemented with a compound semiconductor such as group III-V or group II-VI. The second conductive semiconductor layer 127 has a second conductive semiconductor layer 127 Dopants may be doped. The second conductive semiconductor layer 127 is made of a semiconductor material with the composition formula Inx5Aly2Ga1-x5-y2N (0≤x5≤1, 0≤y2≤1, 0≤x5+y2≤1) or AlInN, AlGaAs, GaP, GaAs. , GaAsP, and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, Ba, etc., the second conductive semiconductor layer 127 doped with the second dopant may be a p-type semiconductor layer.

The second conductive semiconductor layer 127 may include 2-1 to 2-3 conductive type semiconductor layers 127a, 127b, and 127c. The 2-1st conductivity type semiconductor layer 127a may have a smaller aluminum composition than the 2-2nd conductivity type semiconductor layer 127b.

An electron blocking layer 129 may be disposed between the active layer 126 and the second conductive semiconductor layer 127. The electron blocking layer 129 blocks the flow of electrons supplied from the first conductive semiconductor layer 124 to the second conductive semiconductor layer 127, allowing electrons and holes to recombine within the active layer 126. You can increase your odds. The energy band gap of the electron blocking layer 129 may be larger than that of the active layer 126 and/or the second conductive semiconductor layer 127.

The electron blocking layer 129 is a semiconductor material having the composition formula In _x1 Al _y1 Ga _{1 -x1- y1} N (0≤x1≤1, 0≤y1≤1, 0≤x1+y1≤1), for example, AlGaN. , InGaN, InAlGaN, etc., but is not limited thereto. The electron blocking layer 129 may include a first layer 129b having a high aluminum composition and a second layer 129a having a low aluminum composition alternately disposed.

Referring to Figure 2, the first conductive semiconductor layer 124, the barrier layer 126b, the well layer 126a, and the 2-1 to 2-3 conductive semiconductor layers 127a, 127b, and 127c are all May contain aluminum. Accordingly, the first conductive semiconductor layer 124, the barrier layer 126b, the well layer 126a, and the 2-1 to 2-3 conductive semiconductor layers 127a, 127b, and 127c may be AlGaN. However, it is not necessarily limited to this.

The electron blocking layer 129 may have an aluminum composition of 50% to 90%. The blocking layer 129 may include a plurality of first blocking layers 129a with a relatively high aluminum composition and a plurality of second blocking layers 129b with a low aluminum composition alternately disposed. If the aluminum composition of the blocking layer 129 is less than 50%, the height of the energy barrier to block electrons may be insufficient and light emitted from the active layer 126 may be absorbed by the blocking layer 129, and the aluminum composition may be 90%. If it exceeds %, the electrical characteristics of the semiconductor device may deteriorate.

The electron blocking layer 129 may include a 1-1 section 129-1 and a 1-2 section 129-2. The aluminum composition of the 1-1 section 129-1 may increase as it approaches the blocking layer 129. The aluminum composition of the 1-1 section (129-1) may be 80% to 100%. That is, the 1-1 section (129-1) may be AlGaN or AlN. Alternatively, the 1-1 section 129-1 may be a superlattice layer in which AlGaN and AlN are alternately arranged.

The thickness of the 1-1 section 129-1 may be about 0.1 nm to 4 nm. If the thickness of the 1-1 section (129-1) is thinner than 0.1 nm, there may be a problem of not effectively blocking the movement of electrons. Additionally, if the thickness of the 1-1 section 129-1 is thicker than 4 nm, there may be a problem in that the efficiency of hole injection into the active layer is reduced.

The 1-2 section 129-2 may include an undoped section. The 1-2 section 129-2 may serve to prevent the dopant from diffusing from the second conductive semiconductor layer 127 to the active layer 126.

The thickness of the 2-2nd conductivity type semiconductor layer 127b may be greater than 10 nm and less than 200 nm. For example, the thickness of the 2-2 conductivity type semiconductor layer 127b may be 25 nm. If the thickness of the 2-2 conductive semiconductor layer 127b is less than 10 nm, resistance increases in the horizontal direction and current injection efficiency may decrease. Additionally, if the thickness of the 2-2 conductive semiconductor layer 127b is greater than 200 nm, resistance may increase in the vertical direction and current injection efficiency may decrease.

The aluminum composition of the 2-2 conductive semiconductor layer 127b may be higher than that of the well layer 126a. To generate ultraviolet light, the aluminum composition of the well layer 126a may be about 30% to 70%. If the aluminum composition of the 2-2 conductive semiconductor layer 127b is lower than the aluminum composition of the well layer 126a, the light extraction efficiency will decrease because the 2-2 conductive semiconductor layer 127b absorbs light. You can. However, in order to prevent the crystallinity of the light emitting structure from deteriorating, the method is not necessarily limited to this. For example, the aluminum composition in some sections of the 2-2 conductive semiconductor layer 127b may be lower than the aluminum composition of the well layer 126a.

The aluminum composition of the 2-2 conductive semiconductor layer 127b may be greater than 40% and less than 80%. If the aluminum composition of the 2-2 conductive semiconductor layer 127b is less than 40%, there is a problem of absorbing light, and if it is greater than 80%, there is a problem that current injection efficiency deteriorates. For example, if the aluminum composition of the well layer 126a is 30%, the aluminum composition of the 2-2 conductivity type semiconductor layer 127b may be 40%.

The aluminum composition of the 2-1 conductivity type semiconductor layer 127a may be lower than that of the well layer 126a. If the aluminum composition of the 2-1 conductive semiconductor layer 127a is higher than the aluminum composition of the well layer 126a, the resistance between the p-ohmic electrodes increases, resulting in insufficient ohmic generation and low current injection efficiency. .

The aluminum composition of the 2-1 conductivity type semiconductor layer 127a may be greater than 1% and less than 50%. If the composition is greater than 50%, sufficient ohmic contact with the p-ohmic electrode may not be achieved, and if the composition is less than 1%, there is a problem of light absorption as it is close to the GaN composition.

The thickness of the 2-1 conductivity type semiconductor layer 127a may be 1 nm to 30 nm, or 1 nm to 10 nm. As described above, the 2-1 conductivity type semiconductor layer 127a can absorb ultraviolet light because it has a low aluminum composition for ohmic properties. Therefore, it may be advantageous in terms of light output to control the thickness of the 2-1 conductivity type semiconductor layer 127a as thin as possible.

However, when the thickness of the 2-1 conductivity type semiconductor layer 127a is controlled to 1 nm or less, the 2-1 conductivity type semiconductor layer 127a is not disposed in some sections, and the 2-2 conductivity type semiconductor layer 127b ) may occur in an area exposed to the outside of the light emitting structure 120. Additionally, if the thickness is greater than 30 nm, the amount of light absorbed by the 2-1 conductivity type semiconductor layer 127a may become too large, thereby reducing light output efficiency.

The thickness of the 2-1st conductivity type semiconductor layer 127a may be smaller than the thickness of the 2-2nd conductivity type semiconductor layer 127b. The thickness ratio of the 2-2nd conductivity type semiconductor layer 127b and the 2-1st conductivity type semiconductor layer 127a may be 1.5:1 to 20:1. If the thickness ratio is less than 1.5:1, the thickness of the 2-2 conductivity type semiconductor layer 127b may become too thin and current injection efficiency may decrease. Additionally, if the thickness ratio is greater than 20:1, the thickness of the 2-1 conductivity type semiconductor layer 127a may become too thin and ohmic reliability may deteriorate.

The aluminum composition of the 2-2nd conductivity type semiconductor layer 127b may decrease as the distance from the active layer 126 increases. Additionally, the aluminum composition of the 2-1 conductivity type semiconductor layer 127a may decrease as the distance from the active layer 126 increases.

At this time, the aluminum reduction width of the 2-1 conductivity type semiconductor layer 127a may be greater than the aluminum reduction width of the 2-2 conductivity type semiconductor layer 127b. That is, the rate of change in the thickness direction of the Al composition ratio of the 2-1 conductivity type semiconductor layer 127a may be greater than the rate of change in the thickness direction of the Al composition ratio of the 2-2 conductivity type semiconductor layer 127b.

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

The 2-3rd conductivity type semiconductor layer 127c may have a uniform aluminum composition. The thickness of the 2-3rd conductivity type semiconductor layer 127c may be 20 nm to 60 nm. The aluminum composition of the 2-3 conductive semiconductor layer 127c may be 40% to 70%.

3 is a conceptual diagram of a semiconductor device according to an embodiment of the present invention.

The light emitting structure 120 of FIG. 3 may have the same configuration as the light emitting structure 120 described in FIG. 1 . The first electrode 142 may be disposed on the upper surface of the recess 128 and electrically connected to the first conductive semiconductor layer 124. The second electrode 246 may be formed below the second conductive semiconductor layer 127.

The second electrode 246 may be electrically connected by contacting the 2-2 conductivity type semiconductor layer.

Since the surface layer of the 2-1 conductivity type semiconductor layer 127a in contact with the second electrode 246 has an aluminum composition of 1% to 10%, ohmic connection can be easily made. Additionally, the 2-1 conductivity type semiconductor layer 127a has a thickness greater than 1 nm and less than 30 nm, so the amount of light absorption may be small.

The first electrode 142 and the second electrode 246 may be ohmic electrodes. The first electrode 142 and the second electrode 246 are made of 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.

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

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

The height of the convex portion of the second electrode pad 166 may be higher than that of the active layer 126. Accordingly, the second electrode pad 166 reflects light emitted from the active layer 126 in the horizontal direction of the device upward, improving light extraction efficiency and controlling the beam angle.

The first insulating layer 131 is partially open at the bottom of the second electrode pad 166, so that the second conductive layer 150 and the second electrode 246 can be electrically connected. The passivation layer 180 may be formed on the top and side surfaces of the light emitting structure 120. The passivation layer 180 may contact the first insulating layer 131 in an area adjacent to the second electrode 246 or under the second electrode 246.

The width d22 of the portion where the first insulating layer 131 is open and the second electrode 246 is in contact with the second conductive layer 150 may be, for example, 40 μm to 90 μm. If it is smaller than 40㎛, there is a problem that the operating voltage increases, and if it is larger than 90㎛, it may be difficult to secure a process margin to avoid exposing the second conductive layer 150 to the outside. If the second conductive layer 150 is exposed to the outer area of the second electrode 246, the reliability of the device may decrease. Therefore, preferably, the width d22 may be 60% to 95% of the total width of the second electrode pad 166.

The first insulating layer 131 may electrically insulate the first electrode 142 from the active layer 126 and the second conductive semiconductor layer 127. Additionally, the first insulating layer 131 may electrically insulate the second electrode 246 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 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, etc. However, it is not limited to this. The first insulating layer 131 may be formed as a single layer or multiple layers. For example, the first insulating layer 131 may be a distributed Bragg reflector (DBR) with a multilayer structure including silver Si oxide or Ti compound. However, the first insulating layer 131 is not necessarily limited to this and 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 is reflected upward, thereby improving light extraction efficiency. As will be described later, in an 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 246. Accordingly, the second electrode pad 166, the second conductive layer 150, and the second electrode 246 can form one electrical channel.

The second conductive layer 150 completely surrounds the second electrode 246 and may be in contact with the side and top surfaces of the first insulating layer 131. The second conductive layer 150 is made of a material with good adhesion to the first insulating layer 131, and includes at least one material selected from the group consisting of materials such as Cr, Al, Ti, Ni, and Au, and these materials. It may be made of an alloy and may be made of a single layer or multiple layers.

When the second conductive layer 150 is in contact with the side and top surfaces of the first insulating layer 131, the thermal and electrical reliability of the second electrode 246 can be improved. Additionally, it may have a reflection function that reflects light emitted between the first insulating layer 131 and the second electrode 246 upward.

The second conductive layer 150 may also be disposed at a second separation distance between the first insulating layer 131 and the second electrode 246, which is an area where the second conductive semiconductor layer is exposed. The second conductive layer 150 may contact the side and top surfaces of the second electrode 246 and the side and top surfaces of the first insulating layer 131 at a second separation distance.

In addition, an area where the second conductive layer 150 and the second conductive semiconductor layer 127 are in contact with each other within the second separation distance to form a Schottky junction may be disposed, and current dispersion is facilitated by forming the Schottky junction. It can happen.

The second insulating layer 132 electrically insulates the second electrode 246 and the second conductive layer 150 from the first conductive layer 165. The first conductive layer 165 may penetrate the second insulating layer 132 and 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 with excellent reflectivity. Exemplarily, the first conductive layer 165 may include aluminum. When the first conductive layer 165 includes aluminum, it serves to reflect light emitted from the active layer 126 upward, thereby improving light extraction efficiency.

The bonding layer 160 may include a conductive material. Exemplarily, 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. By way of example, the substrate 170 may include a metal or semiconductor material. The substrate 170 may be a metal with excellent electrical conductivity and/or thermal conductivity. In this case, the heat generated during the operation of the semiconductor device can be quickly released 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.

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

4A and 4B are plan views of a semiconductor device according to an embodiment of the present invention.

If the Al composition of the light emitting structure 120 increases, the current diffusion characteristics within the light emitting structure 120 may decrease. Additionally, the amount of light emitted from the active layer 126 to the side increases compared to a GaN-based blue light emitting device (TM mode). This TM mode can occur in ultraviolet semiconductor devices.

According to an embodiment, the GaN semiconductor that emits light in the ultraviolet wavelength range can form a relatively large number of recesses 128 to dispose the first electrode 142 compared to the GaN semiconductor that emits blue light for current diffusion. .

Referring to Figure 4a, as the Al composition increases, the current dispersion characteristics may deteriorate. Accordingly, the current is distributed only to points near each first electrode 142, and the current density may rapidly decrease at points that are far away. Accordingly, the effective light emission area P2 may be narrowed. The effective light emitting area (P2) can be defined as an area up to a boundary point where the current density is 40% or less based on the current density at a point near the first electrode 142 where the current density is highest. For example, the effective light emitting area P2 may be adjusted according to the level of the injection current and the composition of Al in the range of 5㎛ to 40㎛ from the center of the recess 128.

In particular, the low current density region P3 between the adjacent first electrodes 142 has a low current density and therefore hardly contributes to light emission. Accordingly, the embodiment may improve light output by further arranging the first electrode 142 in the low current density region P3 where the current density is low.

In general, since the GaN semiconductor layer has relatively excellent current dispersion characteristics, it is desirable to minimize the areas of the recess 128 and the first electrode 142. 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, the current diffusion characteristics are relatively low due to the high composition of Al, so it is desirable to reduce the low current density region P3 by increasing the number of first electrodes 142 even if the area of the active layer 126 is sacrificed. You can.

Referring to FIG. 4B, when the number of recesses 128 is 48, the recesses 128 may not be arranged in a straight line in the horizontal and vertical directions, but may be arranged in a zigzag manner. In this case, the area of the low current density region (P3) becomes narrower, allowing most of the active layer to participate in light emission. When the number of recesses 128 is 70 to 110, current can be distributed more efficiently, resulting in lower operating voltage and improved light output. In a semiconductor device that emits UV-C, if the number of recesses 128 is less than 70, the electrical and optical characteristics may deteriorate, and if the number of recesses 128 is more than 110, the electrical characteristics may be improved, but the volume of the light-emitting layer is reduced, thereby reducing the optical characteristics. This may deteriorate.

The first area where the plurality of first electrodes 142 are in contact with the first conductive semiconductor layer 122 is between 7.4% and 20%, or between 10% and 20% of the maximum cross-sectional area in the horizontal direction of the light emitting structure 120. You can. The first area may be the sum of the areas where each first electrode 142 is in contact with the first conductive semiconductor layer 122.

If the first area of the plurality of first electrodes 142 is less than 7.4%, sufficient current diffusion characteristics cannot be obtained and the light output is reduced, and if it exceeds 20%, the areas of the active layer and the second electrode are excessively reduced. As a result, there is a problem that the operating voltage increases and the optical output decreases.

Additionally, the total area of the plurality of recesses 128 may be 13% to 30% of the maximum horizontal cross-sectional area of the light emitting structure 120. If the total area of the recess 128 does not satisfy the above conditions, it is difficult to control the total area of the first electrode 142 to be 7.4% or more and 20% or less. Additionally, there is a problem that the operating voltage increases and the light output decreases.

The second area where the second electrode 246 is in contact with the second conductive semiconductor layer 126 may be between 35% and 70% of the maximum horizontal cross-sectional area of the light emitting structure 120. The second area may be the total area where the second electrode 246 is in contact with the second conductive semiconductor layer 126.

If the second area is less than 35%, the area of the second electrode becomes excessively small, causing the operating voltage to increase and hole injection efficiency to decrease. If the second area exceeds 70%, the first area cannot be effectively expanded, resulting in a decrease in electron injection efficiency.

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 first electrodes, the area of the second electrode decreases. In order to increase light output, the dispersion characteristics of electrons and holes must be balanced. Therefore, it is important to determine an appropriate ratio between the first area and the second area.

The ratio (first area: second area) of the first area where the plurality of first electrodes are in contact with the first conductive semiconductor layer and the second area where the second electrode is in contact with the second conductive semiconductor layer is 1:3. It may be from 1:10 to 1:10.

When the area ratio is greater than 1:10, the first area is relatively small and the current dispersion characteristics may deteriorate. Additionally, when the area ratio becomes smaller than 1:3, there is a problem in that the second area becomes relatively smaller.

Figure 5 is a SIMS graph of a light emitting structure according to the first embodiment of the present invention, and Figure 6 is a partial enlarged view of Figure 5.

Referring to Figures 5 and 6, the aluminum composition and the composition of the P-type impurity (Mg) of the light emitting structure may change in a direction in which the thickness decreases. As the second conductive semiconductor layer 127 moves toward the surface of the second conductive semiconductor layer 127 , the aluminum composition may decrease and the P-type impurity (Mg) composition may increase.

The second conductive semiconductor layer 127 has a second shortest distance (W2) from the surface (point where thickness is 0, first surface) to the second point (P21) and a second shortest distance (W2) from the surface to the first point (P11). 1 The ratio (W2:W1) of the shortest distance (W1) may be 1:1.25 to 1:100, or 1:1.25 to 1:10.

If the ratio (W2:W1) of the second shortest distance (W2) and the first shortest distance (W1) is less than 1:1.25, the first shortest distance (W1) and the second shortest distance (W2) become closer and the aluminum composition changes. A problem may arise where the temperature suddenly increases. In addition, when the ratio (W2:W1) is greater than 1:100, the thickness of the second conductive semiconductor layer 127 becomes too thick and the crystallinity of the second conductive semiconductor layer 127 decreases, or the There is a problem that the wavelength of light emitted from the active layer changes because the stress can become strong.

Here, the first point P11 may be a point having the same aluminum composition as the aluminum composition of the well layer 126a closest to the second conductive semiconductor layer 127 in the active layer. The range of the first point (P11) can be defined by the spectrum measured by SIMS. The range of the first point P11 can be defined as the second conductivity type semiconductor layer equal to the aluminum content in the well layer of the active layer.

To measure and define the first point (P11), a method based on the SIMS spectrum can be applied, but is not necessarily limited to this. As another example, TEM and XRD measurement methods can be applied, but most simply, it can be defined through SIMS spectrum.

The second point P21 may be a point where the spectrum for the dopant (eg, Mg) of the second semiconductor layer and the spectrum for aluminum intersect in the SIMS spectrum. In measurement, the unit of value for the dopant of the second semiconductor layer may be different, but the point where the spectrum for the dopant of the second semiconductor layer intersects within the region containing the inflection point for the aluminum composition of the second conductive semiconductor layer. The boundary area of the 2-1st semiconductor layer 127a and the 2-2nd semiconductor layer 127b may be included within a range including . Accordingly, the boundary area between the 2-1 semiconductor layer 127a and the 2-2 semiconductor layer 127b can be measured and its range can be defined. However, it is not necessarily limited to this, and the second point (P21) may be a point located within an area where the aluminum composition is 5% to 55%. If the aluminum composition at the second point (P21) is less than 5%, the thickness of the 2-1 conductivity type semiconductor layer 127a may become too thin, and the power consumption efficiency of the semiconductor device may decrease, and if it exceeds 55% In this case, the thickness of the 2-1 conductive type semiconductor layer 127a may become too thick, which may cause a problem of reduced light extraction efficiency. At this time, the aluminum composition at the second point (P21) may be smaller than the aluminum composition at the first point (P11). For example, the second point (P21) may have an aluminum composition of 40% to 70%.

For example, the first shortest distance (W1) may be 25 nm to 100 nm, and the second shortest distance (W2) may be 1 nm to 20 nm.

A first difference (H1) between the average aluminum composition of the electron blocking layer 129 and the aluminum composition at the first point (P11) and a second difference between the average aluminum composition of the electron blocking layer and the aluminum composition at the second point (P21) The ratio (H1:H2) of the difference (H2) may be 1:1.2 to 1:10.

When the ratio (H1:H2) of the first difference to the second difference is less than 1:1.2, the change in aluminum composition in the section between the first point (P11) and the second point is gradual, making it difficult to sufficiently lower the aluminum composition in the contact layer. There is. In addition, when the ratio (H1:H2) of the first difference to the second difference is greater than 1:10, the change in aluminum composition may be rapid and the probability of absorbing light emitted from the active layer may increase.

Figure 7 is a SIMS graph of a light emitting structure according to a second embodiment of the present invention, Figure 8 is a partial enlarged view of Figure 7, and Figure 9 is a SIMS graph of a light emitting structure according to a third embodiment of the present invention. SIMS) graph, and FIG. 10 is a partial enlarged view of FIG. 9.

7 to 10, the ratio (W2:W1) between the above-described second shortest distance (W2) and first shortest distance (W1) is 1:1.25 to 1:100, or 1:1.25 to 1:10. It can be seen that is satisfied. Referring to FIG. 10 as an example, it can be seen that the first point (P13) and the second point (P23) are placed very close to each other.

In addition, the first difference between the average aluminum composition of the electron blocking layer 129 and the aluminum composition at the first points (P12 and P13), and the average aluminum composition of the electron blocking layer and the aluminum composition at the second points (P22 and P23) It can be seen that the ratio of the second difference in composition (H1:H2) satisfies 1:1.2 to 1:10.

If these conditions are met, the aluminum composition on the surface of the second conductive semiconductor layer 127 can be adjusted to 1% to 10%.

Figure 11 is a conceptual diagram of a light emitting device package according to an embodiment of the present invention.

Semiconductor devices are packaged and can be used for curing resin, resist, SOD, or SOG. Alternatively, semiconductor devices may be used for medical purposes or for sterilization of air purifiers or water purifiers.

Referring to FIG. 11, 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 and electrically connected to the semiconductor device 1. It may include a pair of lead frames 5a and 5b that are connected. The semiconductor device 1 may include all of the above-described configurations.

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

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

Semiconductor devices can be used as a light source for a lighting system, a light source for an image display device, or a light source for a lighting device. In other words, the semiconductor device can be applied to various electronic devices that are placed in a case and provide light. For example, when using a mixture of semiconductor devices and RGB phosphors, white light with excellent color rendering (CRI) can be implemented.

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

When used as a backlight unit for a video display device, it can be used as an edge-type backlight unit or a direct-type backlight unit. When used as a light source for a lighting device, it can be used as a luminaire or bulb type. It can also be used as a light source for a mobile terminal. It may be possible.

Light-emitting devices include laser diodes in addition to the light-emitting diodes described above.

The laser diode, like the light emitting device, may include a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer of the above-described structure. In addition, the electro-l㎛inescence phenomenon, in which light is emitted when a p-type first conductivity type semiconductor and an n-type second conductivity type semiconductor are bonded and a current is passed, is used. There are differences in the directionality and phase of light. In other words, a laser diode can emit light with one specific wavelength (monochromatic beam) with the same phase and in the same direction by using a phenomenon called stimulated emission and constructive interference. Therefore, it can be used in optical communications, medical equipment, and semiconductor processing equipment.

An example of a light receiving element is a photodetector, which is a type of transducer that detects light and converts the intensity into an electrical signal. Such photodetectors include photocells (silicon, selenium), light output devices (cadmium sulfide, cadmium selenide), photodiodes (e.g., PDs with a peak wavelength in the visible blind spectral region or true blind spectral region), and photovoltaic devices (PDs). Examples include transistors, photomultiplier tubes, photoelectron tubes (vacuum, gas-encapsulated), and IR (Infra-Red) detectors, but embodiments are not limited thereto.

Additionally, semiconductor devices such as photodetectors can generally be manufactured using direct bandgap semiconductors, which have 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 MSM (Metal Semiconductor Metal) type photodetector. there is.

A photodiode, like a light emitting device, may include a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer of the structure described above, and may have 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 created and a current flows. At this time, the size of the current may be approximately proportional to the intensity of light incident on the photodiode.

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

In addition, it can be used as a rectifier in electronic circuits through the rectification characteristics of a general diode using a p-n junction, and can be applied to ultra-high frequency circuits and oscillator circuits.

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 implemented using a p-type or n-type dopant. It may also be implemented using doped semiconductor materials or intrinsic semiconductor materials.

Although the above description focuses on the examples, this is only an example and does not limit the present invention, and those skilled in the art will be able to You will see that various variations and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

120: Light-emitting structure
124: First conductive semiconductor layer
126: active layer
127: Second conductive semiconductor layer
127a: 2-1 conductive semiconductor layer
127b: 2-2 conductive semiconductor layer
127c: 2-3 conductive semiconductor layer
129: Electronic blocking layer

Claims (20)

A light emitting structure including 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 first electrode electrically connected to the first conductive semiconductor layer; and
It includes a second electrode electrically connected to the second conductive semiconductor layer,
The second conductive semiconductor layer includes a first surface on which the second electrode is disposed,
The second conductive semiconductor layer has a ratio (W2:W1) of the second shortest distance (W2) from the first surface to the second point and the first shortest distance (W1) from the first surface to the first point. is 1:1.25 to 1:100,
The first point is a point in the active layer that has the same aluminum composition as the aluminum composition of the well layer closest to the second conductivity type semiconductor layer,
The second point is a point where the aluminum composition and the dopant composition of the second conductive semiconductor layer become the same,
The first conductivity type semiconductor layer, the second conductivity type semiconductor layer, and the active layer include aluminum.
According to paragraph 1,
A semiconductor device wherein the ratio of the second shortest distance to the first shortest distance is 1:1.25 to 1:10.
According to paragraph 1,
A semiconductor device comprising an electron blocking layer disposed between the active layer and the second conductive semiconductor layer.
According to paragraph 3,
The ratio of the first difference between the average aluminum composition of the electron blocking layer and the aluminum composition at the first point and the second difference between the average aluminum composition of the electron blocking layer and the aluminum composition at the second point is 1:1.2 to 1:1.2. 1:10 semiconductor device.
According to paragraph 1,
The second conductive semiconductor layer is,
A semiconductor device comprising a 2-1 conductivity type semiconductor layer and a 2-2 conductivity type semiconductor layer disposed between the active layer and the 2-1 conductivity type semiconductor layer.
According to clause 5,
The second conductivity type semiconductor layer is a semiconductor device including a 2-3 conductivity type semiconductor layer disposed between the active layer and the 2-2 conductivity type semiconductor layer.
According to clause 6,
A semiconductor device wherein the aluminum composition of the 2-1 conductivity type semiconductor layer and the 2-2 conductivity type semiconductor layer decreases as the distance from the active layer increases.
In clause 7,
A semiconductor device wherein the aluminum reduction width of the 2-1 conductivity type semiconductor layer is greater than the aluminum reduction width of the 2-2 conductivity type semiconductor layer.
According to paragraph 1,
A semiconductor device wherein the first shortest distance is 25 nm to 100 nm.
According to paragraph 1,
A semiconductor device in which the second shortest distance is 1 nm to 20 nm.
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