Semiconductor device and semiconductor device package including the same

Abstract

In one embodiment, a semiconductor device and a semiconductor device package are disclosed. A semiconductor device includes: a light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first electrode electrically coupled to the first conductive semiconductor layer; and a second electrode electrically coupled to the second conductive semiconductor layer; wherein the first electrode includes a first layer, a second layer, and a third layer, the first layer includes a first metal layer, the first metal layer includes a first metal, and the diffusion coefficient of the first metal is greater than the diffusion coefficient of the third metal contained in the third layer; the thickness of the second layer is in the range of 0.4 to 0.53 times the thickness of the first metal layer.

Description

Technical Field

[0001] The present invention relates to a semiconductor device and a semiconductor device package comprising the semiconductor device. Background Art

[0002] Semiconductor devices including compounds such as GaN and AlGaN have many advantages, such as wide and adjustable band gap energy, and thus can be used in various ways for light emitting devices, light receiving devices, various diodes, and the like.

[0003] In particular, light-emitting devices formed of III-V or II-VI compound semiconductor materials, such as light-emitting diodes or laser diodes, can achieve various colors, such as red, green, blue, or emit ultraviolet light due to the development of thin film growth technology and device materials. The light-emitting device can also emit effective white light by using fluorescent materials or combined colors, and has the advantages of low power consumption, semi-permanent life, high response speed, safety and environmental friendliness compared to existing light sources such as fluorescent lamps and incandescent lamps.

[0004] In addition, due to the development of device materials, when light-receiving devices such as photodetectors or solar cells are manufactured with III-V or II-VI compound semiconductor materials, the light-receiving devices generate photocurrents by absorbing light in various wavelength regions. Therefore, light in various wavelength regions from the gamma ray region to the radio wave region can be used. Moreover, due to the advantages of high response speed, safety, environmental friendliness, and easy adjustment of device materials, light-receiving devices can be easily used in power control or ultra-high frequency circuits or communication modules.

[0005] Therefore, the application of semiconductor devices is expanding to transmission modules of optical communication devices, LED backlights replacing cold cathode fluorescent lamps (CCFLs) which constitute backlight sources of liquid crystal display (LCD) devices, white LED lighting devices that can replace fluorescent lamps or incandescent lamps, vehicle headlights, traffic lights, sensors for sensing gas or fire, etc. Moreover, the application of semiconductor devices can be expanded to high-frequency application circuits, power control devices, and communication modules.

[0006] In particular, a light emitting device that emits light in the ultraviolet wavelength region has a curing effect or a sterilizing effect, and thus can be used for curing, medical treatment, and disinfection.

[0007] Active research is currently being conducted on ultraviolet light emitting devices. However, vertical ultraviolet light emitting devices are difficult to manufacture and have relatively low light extraction efficiency. Summary of the invention

[0008] Technical issues

[0009] The present invention is directed to providing a semiconductor device having improved light extraction efficiency.

[0010] The present invention also aims to provide a semiconductor device with excellent current injection efficiency.

[0011] The present invention also aims to provide a semiconductor device in which the characteristics of a first electrode are improved by suppressing a ball-up phenomenon.

[0012] The purpose of the present invention is not limited thereto, and the present invention may include purposes and effects that can be derived from the technical solutions or embodiments described below.

[0013] Technical Solution

[0014] One aspect of the present invention provides a semiconductor device, comprising: a light emitting structure, comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first electrode, electrically coupled to the first conductive semiconductor layer; a second electrode, electrically coupled to the second conductive semiconductor layer; a reflective layer, disposed on the second electrode; and a capping layer, disposed on the reflective layer and comprising a plurality of layers. The capping layer comprises a first layer disposed on the reflective layer, and the first layer comprises Ti.

[0015] The cover layer may further include an intermediate layer disposed on the first layer and including a plurality of layers, the intermediate layer may include a first intermediate layer directly disposed on the first layer and including Ni, and a thickness ratio of the first layer to the first intermediate layer may be in a range of 1:1 to 3:1.

[0016] The cover layer may further include a second layer disposed on the first layer, and the second layer may include Au.

[0017] The first layer may be disposed on one side of the cover layer, and the second layer may be disposed on the other side of the cover layer.

[0018] The intermediate layer may include at least one first intermediate layer including Ni.

[0019] One of the at least one first intermediate layer may be disposed on the first layer.

[0020] A thickness ratio of the first layer to the first intermediate layer may be in the range of 1:1 to 3:1.

[0021] The intermediate layer may further include at least one second intermediate layer including Ti.

[0022] A bonding layer may be additionally provided between the second electrode and the reflective layer.

[0023] The light emitting structure may further include a plurality of grooves passing through the second conductive semiconductor layer and the active layer and extending to a partial region of the first conductive semiconductor layer, and the plurality of first electrodes may be disposed in the plurality of grooves.

[0024] Another aspect of the present invention provides a semiconductor device, comprising: a light emitting structure, comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first electrode, electrically coupled to the first conductive semiconductor layer; and a second electrode, electrically coupled to the second conductive semiconductor layer. The first electrode comprises a first layer, a second layer, and a third layer, the first layer comprises a first metal layer comprising a first metal, the diffusion coefficient of the first metal being greater than the diffusion coefficient of the third metal contained in the third layer, and the thickness of the second layer is in the range of 0.4 to 0.53 times the thickness of the first metal layer.

[0025] The second layer may be disposed between the first metal layer and the third layer.

[0026] The first layer may further include a 1-1 layer and a 1-2 layer disposed between the 1-1 layer and the first metal layer, and a thickness of the first metal layer may be in a range of 1.5 to 2.5 times the sum of thicknesses of the 1-1 layer and the 1-2 layer.

[0027] The 1-1 layer may contain Cr, and the 1-2 layer may contain Ti.

[0028] The semiconductor device may further include: a reflective layer disposed on the second electrode; and a capping layer disposed on the reflective layer and including a plurality of layers.

[0029] The light emitting structure may further include a plurality of grooves passing through the second conductive semiconductor layer and the active layer and extending to a partial region of the first conductive semiconductor layer, and the first electrode may be disposed in the plurality of grooves.

[0030] Another aspect of the present invention provides a semiconductor device, comprising: a light emitting structure, comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first electrode, electrically coupled to the first conductive semiconductor layer and comprising a plurality of layers; and a second electrode, electrically coupled to the second conductive semiconductor layer. The first electrode comprises a first layer, a second layer, and a third layer, the first layer comprises a first region and a second region, a diffusion coefficient of a first metal contained in the first layer is greater than a diffusion coefficient of a third metal contained in the third layer, a ratio of the first metal contained in the second region is greater than a ratio of the first metal contained in the first region, and a thickness ratio of the first region to the second region is in a range of 3:7 to 6.3:3.5.

[0031] The second layer may be disposed between the second region and the third layer.

[0032] The first metal may be Al, and a ratio of an Al ratio of the first region to an Al ratio of the second region may be in a range of 1:1.5 to 1:2.5.

[0033] Another aspect of the present invention provides a semiconductor device package, comprising: a main body and a semiconductor device. The semiconductor device comprises: a light emitting structure, comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first electrode electrically coupled to the first conductive semiconductor layer; a second electrode electrically coupled to the second conductive semiconductor layer; a reflective layer disposed on the second electrode; and a covering layer disposed on the reflective layer and comprising a plurality of layers. The covering layer comprises a first layer disposed on the reflective layer, the first layer comprising Ti.

[0034] Beneficial Effects

[0035] According to an embodiment of the present invention, light extraction efficiency may be improved by minimizing dark spots in a reflective layer of a semiconductor device.

[0036] Furthermore, by stacking the capping layer of the semiconductor device in multiple layers, stress can be relieved and current injection efficiency can also be improved.

[0037] Furthermore, by suppressing the spheroidization phenomenon of the first electrode, the characteristics of the first electrode (ohmic electrode) of the semiconductor device can be improved.

[0038] Various useful advantages and effects of the present invention are not limited to those mentioned above and will be easily understood from the detailed description of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a conceptual diagram of a semiconductor device according to a first embodiment of the present invention.

[0040] Figure 2a yes Figure 1 Magnified view of part A.

[0041] Figure 2b Show Figure 2a Modification example.

[0042] Figure 3a to Figure 3d Various modifications of the capping layer in the semiconductor device according to the first embodiment of the present invention are shown.

[0043] Figure 4 is a conceptual diagram of a semiconductor device according to a second embodiment of the present invention.

[0044] Figure 5a and Figure 5b It is a diagram for describing a configuration in which light output is improved by changing the number of grooves.

[0045] Figure 6a yes Figure 4 Magnified view of part B.

[0046] Figure 6b Show Figure 6a Modification example.

[0047] Figure 7a and Figure 7b Shown is a reflective layer observed before and after changing the capping layer structure in a semiconductor device.

[0048] Figure 8a and Figure 8b Various modifications of the first electrode in the semiconductor device according to the embodiment of the present invention are shown.

[0049] Figures 9a to 9d The balling phenomenon observed in different configurations of the first electrode in the semiconductor device according to the embodiment of the present invention is shown.

[0050] Fig.10 is based on transmission line measurement (TLM) Figures 9a to 9d A graph of the voltage and current values ​​of the first electrode.

[0051] Fig.11 is a conceptual diagram of a semiconductor package according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The embodiments of the present invention may be modified into other forms, and several embodiments may be combined with each other. The scope of the present invention is not limited to each embodiment described below.

[0053] Even when the description of a specific embodiment is not repeated in another embodiment, the description can be understood as being related to another embodiment unless there is a contrary statement or some contradiction in the other embodiment.

[0054] For example, assuming that the characteristics of configuration A are described in a specific embodiment, and the characteristics of configuration B are described in another embodiment, even if an embodiment combining configuration A and configuration B is not clearly described, it should be understood that the embodiment belongs to the scope of the present invention unless there is a contrary statement or some contradiction.

[0055] When describing an embodiment, when it is stated that any one element is formed "above or below" another element, the two elements may be formed to be in direct contact with each other, or may be formed to be in indirect contact with each other, that is, one or more other elements may be formed between the two elements. In addition, the term "above or below" may represent an upward direction relative to an element as well as a downward direction of the element.

[0056] The semiconductor device may include various types of electronic devices, such as a light emitting device and a light receiving device. Each of the light emitting device and the light receiving device may include a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer.

[0057] The semiconductor device according to the embodiment of the present invention may be a light emitting device.

[0058] When electrons combine with holes, light-emitting devices emit light, and the wavelength of the light is determined by the unique energy band gap of the material. Therefore, the light emitted can vary depending on the composition of the material.

[0059] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those having ordinary skill in the art to which the present invention pertains can easily implement the embodiments.

[0060] Figure 1 is a conceptual diagram of a semiconductor device according to a first embodiment of the present invention. Figure 2a yes Figure 1 Magnified view of part A. Figure 2b Show Figure 2a Modification example. Figures 3a to 3d Various modifications of the capping layer in the semiconductor device according to the first embodiment of the present invention are shown.

[0061] The semiconductor device according to the embodiment of the present invention can output light in the ultraviolet wavelength range. For example, the semiconductor device can output light in the near ultraviolet (UV-A) wavelength range, light in the far ultraviolet (UV-B) wavelength range, and light in the deep ultraviolet (UV-C) wavelength range. The wavelength range can be determined by the composition ratio of Al in the semiconductor device.

[0062] For example, light in the near ultraviolet (UV-A) wavelength range may have a wavelength of 320 nm to 420 nm, light in the far ultraviolet (UV-B) wavelength range may have a wavelength of 280 nm to 320 nm, and light in the deep ultraviolet (UV-C) wavelength range may have a wavelength of 100 nm to 280 nm.

[0063] Reference Figure 1 and Figure 2a , the semiconductor device 100 according to the first embodiment of the present invention may include a light emitting structure 110 , a second electrode 125 , a reflective layer 132 , and a capping layer 140 .

[0064] The light emitting structure 110 may include a first conductive semiconductor layer 111 , a second conductive semiconductor layer 112 , and an active layer 113 disposed between the first conductive semiconductor layer 111 and the second conductive semiconductor layer 112 .

[0065] The first conductive semiconductor layer 111 may be implemented as a semiconductor composed of a compound including group V or group VI, and may be doped with a first dopant. The first conductive semiconductor layer 111 may be selected from a semiconductor having an empirical formula of “In x1 Al y1 Ga 1-x1-y1N(0≤x1≤1,0≤y1≤1,0≤x1+y1≤1)”, such as GaN, AlGaN, InGaN and InAlGaN. The first dopant may be an n-type dopant such as Si, Ge, Sn and Te. When the first dopant is an n-type dopant, the first conductive semiconductor layer 111 doped with the first dopant may be an n-type semiconductor layer.

[0066] The second conductive semiconductor layer 112 may be implemented as a semiconductor composed of a compound including group V or group VI, and may be doped with a second dopant. The second conductive semiconductor layer 112 may be composed of a semiconductor having an empirical formula of “In x5 Al y2 Ga 1-x5-y2 N(0≤x5≤1,0≤y2≤1,0≤x5+y2≤1)" or a material selected from AlInN, AlGaAs, GaP, GaAs, GaAsP and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr and Ba, the second conductive semiconductor layer 112 doped with the second dopant can be a p-type semiconductor layer.

[0067] The active layer 113 may be disposed between the first conductive semiconductor layer 111 and the second conductive semiconductor layer 112. In the active layer 113, electrons (or holes) injected through the first conductive semiconductor layer 111 encounter holes (or electrons) injected through the second conductive semiconductor layer 112. When the electrons and holes are recombined, the active layer 113 may be converted to a low energy level and generate light having an ultraviolet wavelength.

[0068] The active layer 113 may have any one of a single well structure, a multi-well structure, a single quantum well structure, a multi-quantum well structure, a quantum dot structure, and a quantum wire structure, but the structure of the active layer 113 is not limited thereto.

[0069] The second electrode 125 may be disposed on the second conductive semiconductor layer 112. The second electrode 125 may make ohmic contact with the second conductive semiconductor layer 112. In the cross-sectional view of the semiconductor device 100, an end of the second electrode 125 may be located more inner than an end of the second conductive semiconductor layer 112.

[0070] The second electrode 125 may include a transparent conductive oxide (TCO) that absorbs relatively less ultraviolet light. The TCO may be selected from indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), aluminum gallium zinc oxide (AGZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZO nitride (IZON), ZnO, IrOx, RuOx, NiO, etc.

[0071] According to an embodiment, the second electrode 125 may be in direct contact with a semiconductor layer having a band gap larger than the energy of ultraviolet light (e.g., p-AlGaN). Generally, the second electrode 125 is disposed on a semiconductor layer having a small band gap (e.g., a GaN layer) for ohmic contact, which involves the problem that most ultraviolet light is absorbed in the GaN layer. However, the second electrode 125 of this embodiment is in direct ohmic contact with a semiconductor layer having a large band gap (e.g., p-AlGaN), and therefore, most light can pass through the second conductive semiconductor layer 112.

[0072] For example, the surface layer of the second conductive semiconductor layer 112 contacting the second electrode 125 may have an Al composition of 1% to 10%. When the Al composition of the surface layer is less than 1%, light is excessively absorbed, and when the Al composition is greater than 10%, ohmic characteristics may be reduced.

[0073] At the same time, the second electrode 125 can generally absorb ultraviolet light. Therefore, it is necessary to improve the light extraction efficiency while maintaining the ohmic contact of the second electrode 125. In other words, in the present invention, TCO can be used as the second electrode to improve the light extraction efficiency while maintaining the ohmic characteristics. In the present invention, since the second electrode is TCO, the transparency can be improved, and since the conductive layer (reflective layer) has a reflective property and is disposed below the second electrode 125, the light extraction efficiency can be improved.

[0074] The second electrode 125 may have a thickness T1 of 1 nm to 10 nm. When the thickness of the second electrode 125 is less than 1 nm, cracks may be easily generated due to external impact, and resistance increases so that current injection efficiency may be reduced. Moreover, when the thickness of the second electrode 125 is greater than 10 nm, transmittance is reduced, so that light loss may occur.

[0075] The reflective layer 132 may be disposed on the second electrode 125. The reflective layer 132 may be disposed to cover the second electrode 125. For example, the reflective layer 132 may be disposed to surround the second electrode 125 except for an interface between the second conductive semiconductor layer 112 and the second electrode 125. The reflective layer 132 may be electrically coupled to the second electrode 125. Therefore, current may be applied to the second conductive semiconductor layer 112 through the reflective layer 132.

[0076] The reflective layer 132 may be formed of a material having a high reflectivity. The reflective layer 132 may reflect light emitted from the active layer 113. A bonding layer 132a may be additionally provided between the second electrode 125 and the reflective layer 132. The bonding layer 132a may increase the bonding strength between the second electrode 125 and the reflective layer. The bonding layer 132a may be provided to surround the second electrode 125. Alternatively, the bonding layer 132a may be provided to cover not only the second electrode 125 but also at least a portion of the second conductive semiconductor layer 112.

[0077] The bonding layer 132a can be formed into a single layer or multiple layers by a material selected from Cr, ITO and Ti or a combination thereof. When the bonding layer 132a includes ITO, the ITO may further include various materials that can increase the bonding strength. For example, the ITO may also include at least one material selected from N, Zn and Ga. When depositing ITO, these materials may also be deposited and arranged in the entire ITO region, or may be arranged only on the surface of the ITO by surface treatment. However, the material of the bonding layer 132a is not limited thereto.

[0078] The bonding layer 132a may have a thickness T2 of 1 nm to 5 nm. The thickness of the bonding layer 132a may indicate a maximum height from an interface between the bonding layer 132a and the second electrode 125. When the thickness of the bonding layer 132a is less than 1 nm, the bonding strength between the second electrode 125 and the reflective layer 132 may be reduced. When the thickness of the bonding layer 132a is greater than 5 nm, the transmittance is reduced, and thus light loss may occur.

[0079] The reflective layer 132 may have a thickness T3 of 50 nm to 2000 nm. The thickness of the reflective layer 132 may indicate a maximum height from an interface between the reflective layer 132 and the bonding layer 132a. When the thickness of the reflective layer 132 is less than 50 nm, reflectivity may decrease. When the thickness of the reflective layer 132 is greater than 2000 nm, reflection efficiency may hardly improve.

[0080] The capping layer 140 may be disposed on the reflective layer 132. The capping layer 140 may be disposed to cover the reflective layer 132. The capping layer 140 may be electrically coupled to the reflective layer 132. The capping layer 140 may improve physical reliability by protecting the reflective layer 132. In addition, the capping layer 140 may provide current to the second conductive semiconductor layer 112. The capping layer 140 may also function as a current spreading layer.

[0081] The cover layer 140 may be formed of a material selected from Ti, Ni, and Au or a combination thereof as a single layer or multiple layers. However, the present invention is not limited thereto. In particular, the cover layer 140 may have a region in contact with the reflective layer 132. Ti may be provided in a region of the cover layer in contact with the reflective layer 132. The structure of the cover layer 140 will be described in detail below.

[0082] refer to Figure 2a , the end of the second electrode 125 may be separated from the end of the reflective layer 132 by a spacing distance D1. Specifically, from the center C1 of the second electrode 125 (see Figure 1 ) to the end of the reflective layer 132 may be greater than the distance from the center C1 of the second electrode 125 to the end of the reflective layer 132. Since the reflective layer 132 extends to cover the side surface of the second electrode 125, light emitted toward the side surface of the second electrode 125 may be reflected upward. In this way, the semiconductor device 100 according to the embodiment may improve light extraction efficiency.

[0083] The spacing distance D1 between the end of the second electrode 125 and the end of the reflective layer 132 may be in the range of 2.5 μm to 5 μm. When the spacing distance D1 is less than 2.5 μm, the reflectivity may be reduced. When the spacing distance D1 is greater than 5 μm, the stress at the corner of the reflective layer 132 may be increased, and the reflection efficiency may hardly be improved.

[0084] The end of the reflective layer 132 may be spaced apart from the end of the cover layer 140 by a spacing distance D2. Figure 1 ) to the end of the cover layer 140 may be greater than the distance from the center C1 of the reflective layer 132 to the end of the reflective layer 132. Since the cover layer 140 extends to cover the side surface of the reflective layer 132, the reflective layer 132 may be protected.

[0085] The spacing distance D2 between the end of the reflective layer 132 and the end of the cover layer 140 may be in the range of 2.5 μm to 5 μm. When the spacing distance D2 is less than 2.5 μm, the current injection efficiency and the reflective layer protection effect may be reduced. When the spacing distance D2 is greater than 5 μm, the stress at the corner of the cover layer 140 may be increased.

[0086] Figure 2b yes Figure 2a Modification example.

[0087] refer to Figure 2b The end of the second electrode 125 may be spaced apart from the end of the reflective layer 132 by a spacing distance D3. The spacing distance D3 may be in the range of 2.5 μm to 5 μm. Also, the end of the second electrode 125 may be spaced apart from the end of the capping layer 140 by a spacing distance D3.

[0088] In other words, Figure 2b In the embodiment, the end of the reflective layer 132 and the end of the cover layer 140 may be collinear. This is because the side surface of the reflective layer 132 has little effect on the reflection efficiency, and covering the side surface with the cover layer 140 may be meaningless.

[0089] In other words, in the embodiment of the present invention, the reflective layer 132 is configured to completely cover the second electrode 125, which can help improve the reflectivity. Moreover, the covering layer 140 is configured to cover the upper surface of the reflective layer 132 or the entire reflective layer 132, so that the protection effect of the reflective layer 132 can be improved.

[0090] Reference Figures 3a to 3d , various structures 140 - 1 , 140 - 2 , 140 - 3 , and 140 - 4 of the cover layer 140 will be described below.

[0091] First, refer to Figure 3a The cover layer 140 - 1 according to the first embodiment of the present invention may include a first layer 141 , a second layer 142 , and an intermediate layer 143 .

[0092] The first layer 141 may be disposed on the reflective layer 132. For example, the first layer 141 may be in contact with the reflective layer 132. The first layer 141 may include Ti. When Ti is included in the first layer 141, a metal material in the intermediate layer 143 may be prevented from diffusing into the reflective layer 132.

[0093] The second layer 142 may be disposed at the outermost side of the cover layer 140-1. Specifically, in the cover layer 140-1, the second layer 142 may be spaced farthest from the reflective layer 132. The second layer 142 may include Au. Since the second layer 142 includes Au, after the cover layer 140-1 is formed, oxidation or deformation of the material in the cover layer 140-1 may be prevented during several processes to be performed.

[0094] The second layer 142 may have a thickness of 30 nm to 300 nm. When the thickness of the second layer 142 is less than 30 nm, the deformation prevention effect on the cover layer 140-1 may be reduced. When the thickness of the second layer 142 is greater than 300 nm, the film stress may increase.

[0095] The intermediate layer 143 may be disposed between the first layer 141 and the second layer 142. The intermediate layer 143 may be composed of a single layer or multiple layers. The intermediate layer 143 may be composed of one to six layers (the intermediate layer 143 may be omitted, which is the configuration of FIG. 3B and will be described below). When the intermediate layer 143 includes more than six layers, the process time and process complexity may increase, so that the process efficiency may be reduced.

[0096] The intermediate layer 143 may include at least one first intermediate layer 143a including Ni. The first intermediate layer 143a may be disposed on the first layer 141. For example, the first intermediate layer 143a may be in contact with the first layer 141. In addition, the intermediate layer 143 may further include at least one second intermediate layer 143b including Ti. Obviously, the second intermediate layer 143b may be omitted. When the intermediate layer 143 includes a plurality of first intermediate layers 143a and second intermediate layers 143b, the first intermediate layers 143a and second intermediate layers 143b may be alternately disposed.

[0097] As mentioned above, in Figure 3a In the embodiment of the present invention, the covering layer 140-1 may be composed of three to eight layers (the covering layer 140-1 may be composed of one or two layers, which corresponds to Figure 3b and Figure 3d The intermediate layer 143 may be composed of one to six layers. The intermediate layer 143 may include one to three first intermediate layers 143a. Moreover, the intermediate layer 143 may not exist, or may include one to three second intermediate layers 143b.

[0098] When the number of layers constituting the intermediate layer 143 increases, the current injection efficiency of the capping layer 140-1 may be improved. In other words, since the capping layer 140-1 provides current to the second conductive semiconductor layer 112, an increase in the thickness of the capping layer 140-1 may lead to an improvement in the current injection efficiency.

[0099] In the capping layer 140-1, a layer including Ti (the first layer 141 or the second intermediate layer 143b) and a layer including Ni (the first intermediate layer 143a) may be alternately provided. When a plurality of different layers are alternately stacked in this manner, stress can be reduced compared to the case where one thick layer is formed. Therefore, even when the total thickness of the capping layer 140-1 increases, film stress can be relieved and current injection efficiency can also be improved.

[0100] Reference Figure 3b , the cover layer 140-2 according to the second embodiment of the present invention may include a first layer 141 and a second layer 142. The first layer 141 and the second layer 142 may be configured in the same manner as described above. In other words, the cover layer 140-1 shown in FIG. 3A may be obtained by omitting the intermediate layer 143. Figure 3bCovering layer 140-2 is shown.

[0101] Reference Figure 3c , the cover layer 140-3 according to the third embodiment of the present invention may include a first layer 141 and an intermediate layer 143. The first layer 141 and the intermediate layer 143 may be configured in the same manner as described above. In other words, the cover layer 140-3 as shown in FIG. 3C may be obtained by omitting the second layer 142 from the cover layer 140-1 shown in FIG. 3A.

[0102] Reference Figure 3d , the cover layer 140-4 according to the fourth embodiment of the present invention may include a first layer 141. The first layer 141 may be configured in the same manner as described above. In other words, the cover layer 140-4 may be configured in the same manner as described above. Figure 3a The cover layer 140-1 shown in FIG. 1 omits the second layer 142 and the intermediate layer 143 to obtain the Figure 3d Covering layer 140-4 is shown.

[0103] like Figure 3a to Figure 3d As shown, the cover layer 140 may be composed of at least one layer. The cover layer 140 may be composed of one to eight layers. In this case, the intermediate layer 143 in the cover layer 140 may be composed of one to six layers. When the cover layer 140 includes more than eight layers, the process time and process complexity may increase, so that the process efficiency may be reduced.

[0104] Specifically, the covering layer 140 may be made of Ti, Ti / Au, Ti / Ni, Ti / Ni / Au, Ti / Ni / Ti, Ti / Ni / Ti / Au, Ti / Ni / Ti / Ni, Ti / Ni / Ti / Ni / Au, Ti / Ni / Ti / Ni / Ti, Ti / N Any one of i / Ti / Ni / Ti / Au, Ti / Ni / Ti / Ni / Ti / Ni, Ti / Ni / Ti / Ni / Ti / Ni / Au, Ti / Ni / Ti / Ni / Ti / Ni / Ti and Ti / Ni / Ti / Ni / Ti / Ni / Ti / Au is formed.

[0105] The total thickness of the cover layer 140 is 100 nm to 2000 nm. In this case, regardless of the number of layers included in the cover layer 140, the total thickness of the cover layer 140 may be at least 100 nm. For example, even when the cover layer 140 is composed of only a small number of layers such as one or two layers, the thickness of the cover layer 140 may be at least 100 nm. When the thickness of the cover layer 140 is less than 100 nm, the current injection efficiency and the protective effect on the reflective layer 132 may be reduced. When the thickness of the cover layer 140 is greater than 2000 nm, the process time and process complexity may increase, so that the process efficiency may be reduced. Moreover, when the thickness of the cover layer 140 is greater than 2000 nm, the film stress may be increased.

[0106] The first layer 141 in the capping layer 140 may have a thickness of 30 nm to 300 nm. When the thickness of the first layer 141 is less than 30 nm, the material (e.g., Ni) included in the intermediate layer 143 may diffuse into the reflective layer 132. In this case, dark spots (e.g., areas where Ni diffuses) may be generated, and reflectivity may be reduced. When the thickness of the first layer 141 is greater than 300 nm, the stress of the first layer 141 may be increased.

[0107] The first intermediate layer 143a and the second intermediate layer 143b may have a thickness of 10nm to 300nm. When the thickness of the first intermediate layer 143a is less than 10nm, the stress relief effect may hardly be achieved by alternately stacking different layers. When the thickness of the first intermediate layer 143a is greater than 300nm, the film stress may be increased.

[0108] The thickness ratio of the first layer 141 to the first intermediate layer 143a may be in the range of 1:1 to 3:1. When the thickness ratio of the first layer 141 to the first intermediate layer 143a is less than 1:1, the material included in the intermediate layer 143 may diffuse into the reflective layer 132. When the thickness ratio of the first layer 141 to the first intermediate layer 143a is greater than 3:1, the thickness of the first layer 141 is relatively too large, and stress may increase.

[0109] The thickness ratio of the first intermediate layer 143a to the second intermediate layer 143b may be in the range of 1:1 to 1:3. When the thickness ratio of the first intermediate layer 143a to the second intermediate layer 143b is less than 1:1, the material included in the first intermediate layer 143a may diffuse. When the thickness ratio of the first intermediate layer 143a to the second intermediate layer 143b is greater than 1:3, the thickness of the second intermediate layer 143b is relatively too large, and stress may increase.

[0110] Figure 4 is a conceptual diagram of a semiconductor device according to a second embodiment of the present invention. Figure 5a and Figure 5b It is a diagram for describing a configuration in which light output is improved by changing the number of grooves. Figure 6a yes Figure 4 Magnified view of part B. Figure 6b Shows Figure 6a Modification example.

[0111] Reference Figure 4 , the semiconductor device 200 may include a light emitting structure 110 , a plurality of grooves R, a first electrode 121 , a second electrode 125 , a reflective layer 132 , and a capping layer 140 .

[0112] The light emitting structure 110 may have Figure 1The light emitting structure 110 may have the same configuration as described in the above. Protrusions and depressions may be formed on the upper surface of the light emitting structure 110. These protrusions and depressions may improve the extraction efficiency of light emitted from the light emitting structure 110. The average height of the protrusions and depressions may vary depending on the ultraviolet wavelength. In the case of UV-C, the protrusions and depressions may have a height of about 300 nm to about 800 nm, and when the average height is about 500 nm to about 600 nm, the light extraction efficiency may be improved.

[0113] A plurality of grooves R may extend to a partial region of the first conductive semiconductor layer 111 through one surface of the second conductive semiconductor layer 112 and the active layer 113. In the grooves R, the first insulating layer 151 and the second insulating layer 152 may be provided to electrically insulate the first conductive layer 131 from the second conductive semiconductor layer 112 and the active layer 113.

[0114] The first electrode 121 may be disposed on the upper surface of the groove R and electrically coupled to the first conductive semiconductor layer 111. The first electrode 121 may be exposed through the first insulating layer 151 and electrically coupled to the first conductive semiconductor layer 111. The first electrode 121 may be electrically insulated from the active layer 113 and the second conductive semiconductor layer 112 by the first insulating layer 151. The first electrode 121 may be an ohmic electrode.

[0115] The first electrode 121 may be formed to include at least one of ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, GZO, IZON, AGZO, ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, Ni / IrOx / Au / ITO, Ah, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, Mg, Zn, Pt, Au, and Hf, but is not limited to these materials.

[0116] The second electrode 125 may be formed on the second conductive semiconductor layer 112. The second electrode 125 is exposed through the first insulating layer 151 and is electrically coupled to the second conductive semiconductor layer 112. The second electrode 125 may be an ohmic electrode. The second electrode 125 may have a Figure 1 The same configuration disclosed in .

[0117] As described above, the surface layer of the second conductive semiconductor layer 112 contacting the second electrode 125 has an Al composition of 1% to 10%, and thus, current injection may be easy.

[0118] The first conductive layer 131 may be disposed according to the shape of the lower surface of the light emitting structure 110 and the groove R. The first conductive layer 131 may be electrically insulated from the cover layer 140 by the second insulating layer 152. The first conductive layer 131 may be electrically coupled to the first electrode 121 by passing through the second insulating layer 152.

[0119] The first conductive layer 131 may be formed of a material having high reflectivity. For example, the first conductive layer 131 may include Al. When the first conductive layer 131 includes Al, the first conductive layer 131 serves to reflect light emitted from the active layer 113 upward, thereby improving light extraction efficiency.

[0120] The second conductive layer (also described as a reflective layer) 132 may be disposed on the second electrode 125. The reflective layer 132 may be disposed to cover the second electrode 125. The reflective layer 132 may be electrically coupled to the second electrode 125. The reflective layer 132 may be in contact with the side surface and the lower surface of the first insulating layer 151. When the reflective layer 132 is in contact with the side surface and the lower surface of the first insulating layer 151, the thermal and electrical reliability of the second electrode 125 may be improved. Moreover, the reflective layer 132 may be formed of a material having a high reflectivity. For example, the reflective layer 132 may include Al, Ag, Au, or Cu. The reflective layer 132 may be formed of a material having a high adhesive strength with the first insulating layer 151. The reflective layer 132 may improve light extraction efficiency by reflecting light emitted between the first insulating layer 151 and the second electrode 125 upward. The reflective layer 132 may have a Figure 1 The same configuration disclosed in .

[0121] The cover layer 140 may be disposed on the reflective layer 132. The cover layer 140 may be disposed to cover the reflective layer 132. The cover layer 140 may have a Figure 1 Also, the cover layer 140 may have any one of the configurations selected from FIG. 3A to FIG. 3D .

[0122] The first insulating layer 151 may be made of a material selected from SiO2, Si x O y 、Si3N4、Si x N y 、SiO x N y , Al2O3, TiO2, AlN, etc., but is not limited thereto. The first insulating layer 151 and the second insulating layer 152 may be formed as a single layer or a multilayer. For example, the first insulating layer 151 and the second insulating layer 152 may be a multilayer distributed Bragg reflector (DBR) including Si oxide or Ti compound. However, the first insulating layer 151 and the second insulating layer 152 are not necessarily limited thereto and may include various reflective structures.

[0123] When the first and second insulating layers 151 and 152 perform a reflective function, light extraction efficiency can be improved by upwardly reflecting light emitted toward the side surfaces of the first and second insulating layers 151 and 152. When the number of grooves R increases, the ultraviolet semiconductor device can exhibit higher light extraction efficiency than a semiconductor device emitting blue light.

[0124] Specifically, the following will refer to Figure 5a and Figure 5b Describe the change in light output according to the number of grooves.

[0125] Figure 5a and Figure 5b Can be Figure 4 FIG. 2 is a plan view of a semiconductor device 200 in which the light emitting structure 110 is omitted. In other words, the first electrode 121 may be disposed at the center of the groove R. Also, the groove R may be spaced apart from the second electrode 125 by the separation region L.

[0126] When the Al composition in the light emitting structure 110 increases, the current diffusion characteristics in the light emitting structure 110 may be deteriorated. Also, the amount of light emitted from the side surface of the active layer 113 increases compared to the amount of light emitted from the GaN-based blue light emitting device (transverse magnetic (TM) mode). Such a TM mode may be generated from an ultraviolet semiconductor device.

[0127] The current distribution characteristics of the ultraviolet semiconductor device are not as good as those of the blue GaN semiconductor device. Therefore, in the ultraviolet semiconductor device, it is necessary to form a larger number of grooves R than in the blue GaN semiconductor device and to provide the first electrode 121.

[0128] refer to Figure 5a , the current is distributed only near each first electrode 121, and the current density can be sharply reduced at a position far away therefrom. Therefore, the size of the effective light emitting area P1 can be reduced.

[0129] The effective light emitting region P1 may be defined as a region from the center of the first electrode where the current density is highest to a boundary where the current density is 40% or less. For example, the effective light emitting region P1 may be adjusted within 40 μm from the center of the groove R according to the injection current level and the Al composition.

[0130] The low current density region P2 has low current density and thus hardly contributes to light emission. Therefore, according to an embodiment, light output may be improved by additionally disposing the first electrode 121 in the low current density region P2 having low current density or by using a reflective structure.

[0131] Generally, a GaN-based semiconductor device emitting blue light has excellent current distribution characteristics, and therefore, it is preferable to minimize the areas of the groove R and the first electrode 121. This is because when the areas of the groove R and the first electrode 121 increase, the area of ​​the active layer 113 decreases.

[0132] However, according to this embodiment, the current distribution characteristics are relatively poor due to the high Al composition. Therefore, it is preferable to reduce the low current density region P2 even by increasing the number of first electrodes 121 by sacrificing the area of ​​the active layer 113, or to provide a reflective structure in the low current density region P2.

[0133] refer to Figure 5b , when the number of grooves R is 48, the grooves R may be arranged on a horizontal or vertical straight line, and may be arranged in a zigzag shape. In this case, the area of ​​the low current density region P2 is further reduced, and most of the active layer may participate in light emission.

[0134] When the number of grooves R is 70 or 110, current can be distributed more efficiently. Therefore, the operating voltage can be reduced, and the light output can be improved. In a semiconductor device that emits UV-C, when the number of grooves R is less than 70, the electro-optical characteristics may deteriorate. When the number of grooves R is greater than 110, the electrical characteristics can be improved, but the optical characteristics may deteriorate due to the reduction in the volume of the light-emitting layer. In this case, the groove R may have a diameter of 20 μm to 70 μm.

[0135] Meanwhile, the second electrode pad 160 may be disposed in a corner region of the semiconductor device 200. The second electrode pad 160 may be electrically coupled to the reflective layer 132 and the second electrode 125 through the first insulating layer 151. In other words, the second electrode pad 160, the reflective layer 132 and the second electrode 125 may constitute an electrical channel. Moreover, the second electrode pad 160 may be electrically insulated from the first conductive layer 131 by the second insulating layer 152.

[0136] The center of the second electrode pad 160 is recessed so that its upper surface may have a concave portion and a convex portion. A wire (not shown) may be bonded to the concave portion of the second electrode pad 160. Therefore, the wire may be firmly bonded to the second electrode pad 160 due to a large bonding area.

[0137] The second electrode pad 160 may be used to reflect light. Therefore, when the second electrode pad 160 is closer to the light emitting structure 110, the light extraction efficiency of the semiconductor device 200 may be improved. Moreover, the height of the convex portion of the second electrode pad 160 may be greater than the height of the active layer 113. Therefore, the second electrode pad 160 may improve the light extraction efficiency by reflecting the light emitted in the horizontal direction of the device from the active layer 113, and may control the beam angle.

[0138] A bonding layer 170 may be additionally disposed along the lower surface of the light emitting structure 110 and the shape of the groove R. The bonding layer 170 may include a conductive material. For example, the bonding layer 170 may include a material selected from the group consisting of Au, Sn, In, Al, Si, Ag, Ni, and Cu, or an alloy thereof.

[0139] The substrate 180 may be disposed on the bonding layer 170. The substrate 180 may be formed of a conductive material. For example, the substrate 180 may include a metal or a semiconductor material. Moreover, the substrate 180 may be a metal having excellent electrical conductivity and / or thermal conductivity. For example, the substrate 180 may include a material selected from the group consisting of Si, Mo, W, Cu and Al, or an alloy thereof. In this case, the heat generated during operation of the semiconductor device can be quickly transferred to the outside.

[0140] The passivation layer 190 may be formed on the upper surface and the side surface of the light emitting structure 110. The passivation layer 190 may contact the first insulating layer 151 in a region adjacent to the second electrode 125.

[0141] refer to Figure 6a , the end of the second electrode 125 may be separated from the end of the reflective layer 132 by a spacing distance D4. Specifically, from the center C2 of the second electrode 125 (see Figure 4 ) to the end of the reflective layer 132 may be greater than the distance from the center C2 of the second electrode 125 to the end of the second electrode 125. Since the reflective layer 132 extends to cover the side surface of the second electrode 125, light emitted toward the side surface of the second electrode 125 may be reflected upward, so that light extraction efficiency may be improved.

[0142] The spacing distance D4 between the end of the second electrode 125 and the end of the reflective layer 132 may be in the range of 2.5 μm to 5 μm. When the spacing distance D4 is less than 2.5 μm, the reflectivity may be reduced. When the spacing distance D4 is greater than 5 μm, the stress at the corner of the reflective layer 132 may be increased, and the reflection efficiency may hardly be improved.

[0143] The end of the reflective layer 132 may be spaced apart from the end of the cover layer 140 by a spacing distance D5. Figure 4 ) to the end of the cover layer 140 may be greater than the distance from the center C2 of the reflective layer 132 to the end of the reflective layer 132. Since the cover layer 140 extends to cover the side surface of the reflective layer 132, the reflective layer 132 may be protected.

[0144] The spacing distance D5 between the end of the reflective layer 132 and the end of the cover layer 140 may be in the range of 2.5 μm to 5 μm. When the spacing distance D5 is less than 2.5 μm, the current injection efficiency and the protective effect on the reflective layer may be reduced. When the spacing distance D5 is greater than 5 μm, the stress at the corner of the cover layer 140 may be increased.

[0145] Figure 6b Shows Figure 6a Modification example.

[0146] refer to Figure 6b , the end of the second electrode 125 may be spaced apart from the end of the reflective layer 132 by a spacing distance D6. The spacing distance D6 may be in the range of 2.5 μm to 5 μm. Moreover, the end of the second electrode 125 and the end of the cover layer 140 may be spaced apart from each other by a spacing distance less than the spacing distance D6. Obviously, the end of the second electrode 125 may be spaced apart from the end of the cover layer 140 by a spacing distance D6.

[0147] In other words, Figure 6b In the embodiment, the end of the cover layer 140 may be formed closer to the center C2 (see FIG. 1 ) than the end of the reflective layer 132. Figure 4 ). In addition, the ends of the reflective layer 132 and the cover layer 140 may be collinear. This is because the side surface of the reflective layer 132 has little effect on the reflection efficiency, and covering the side surface with the cover layer 140 may be meaningless.

[0148] In other words, in the embodiment of the present invention, the reflective layer 132 is configured to completely cover the second electrode 125, which can help increase the reflectivity. Moreover, the cover layer 140 is configured to cover the upper surface of the reflective layer 132 or the entire reflective layer 132, so that the protection effect of the reflective layer 132 can be improved.

[0149] <Experimental example>

[0150] Reflection layer observation

[0151] Figure 7a and Figure 7b Shown is a reflective layer observed before and after changing the capping layer structure in a semiconductor device.

[0152] exist Figure 7a In the embodiment of the present invention, the cover layer is configured as disclosed in the present invention, and in Figure 7b In other words, the middle layer of the cover layer can be configured in different ways. Figure 7a and Figure 7b Shown are the results of observing the samples with an optical microscope after the samples were manufactured into cover layers with different structures and heat-treated at 300°C. Figure 7aThe result of observing the reflective layer at a magnification of 200× through an optical microscope is shown. Figure 7b (a) shows the result of observing the reflective layer with an optical microscope at a magnification of 200×, Figure 7b (b) shows the result of observing the reflective layer at a magnification of 1000×.

[0153] More specifically, in Figure 7a In the case of, the second electrode / bonding layer / reflective layer / covering layer is formed of ITO / Cr / Al / Ti / Ni / Ti / Ni / Au. Figure 7b In the case of , the second electrode / bonding layer / reflective layer / covering layer is formed of ITO / Cr / Al / Ni / Ti / Ni / Au. In other words, in Figure 7a In the case of, the layer of the cover layer (first layer) in direct contact with the reflective layer is formed of Ti, and Figure 7b In the case of , the cover layer in direct contact with the reflective layer is formed of Ni.

[0154] refer to Figure 7a , when the first layer of the capping layer is formed of Ti, no dark spots are observed on the reflective layer. In other words, the first layer can prevent the material of the capping layer (eg, Ni) from diffusing into the reflective layer.

[0155] refer to Figure 7b , when the first layer of the cover layer is formed of Ni, a plurality of dark spots are observed on the reflective layer. In other words, since the first layer is formed of Ni, the material (e.g., Ni) present in the cover layer diffuses into the reflective layer, and dark spots (Ni diffused into the reflective layer) are observed. In particular, in Figure 7b In this case, the reflective layer and the first layer (Ni) are in direct contact with each other, and therefore, Ni is easily diffused.

[0156] Reflectivity measurement

[0157] Table 1 shows the reflectivity measured from the structure of the second electrode / bonding layer / reflective layer / covering layer (first layer). Ni in Comparative Examples 1 and 2 is used as the first layer, and Ti is used as the first layer in Example 1. Comparative Example 1 shows the reflectivity before heat treatment, and Comparative Example 2 and Example 1 show the reflectivity after heat treatment.

[0158] [Table 1]

[0159]

[0160] Referring to Comparative Examples 1 and 2, it can be seen that, although the structures are formed of the same material, the reflectivity decreases after the heat treatment. This is because the diffusion of Ni may be activated by the heat treatment. In other words, many dark spots are generated after the heat treatment, and therefore, the reflectivity decreases. Since semiconductor devices may be exposed to high temperatures during several processes, it is important to ensure an appropriate reflectivity level after the heat treatment.

[0161] Although the reflectance of Example 1 was measured after heat treatment, the reflectance was higher than the reflectance of Comparative Example 1 measured before heat treatment. In other words, by applying Ti to the cover layer (first layer), it is possible to prevent dark spots from being generated in the reflective layer and obtain increased reflectance.

[0162] As described above, in an embodiment of the present invention, the first layer of the cover layer in direct contact with the reflective layer can be formed of Ti. According to the present invention, the first layer can prevent the material in the cover layer from diffusing into the reflective layer. Therefore, the reflectivity can be improved by preventing dark spots from being generated in the reflective layer.

[0163] Figure 8a and Figure 8b Various modifications of the first electrode in the semiconductor device according to the embodiment of the present invention are shown.

[0164] First, we will refer to Figure 8a The first electrode according to the first embodiment is described.

[0165] The first electrode 121-1 may be connected to the first conductive semiconductor layer 111 (see Figure 1 ) ohmic contact and includes at least one conductive material. The first electrode 121-1 may include a plurality of layers. The first electrode 121-1 may include a first surface 121-1a in contact with the first conductive semiconductor layer 111 and a second surface 121-1b in contact with the first conductive layer 131.

[0166] The first electrode 121-1 may include a first layer 122-1, a second layer 123, and a third layer 124. The first layer 122-1 may include a 1-1 layer 122a, a 1-2 layer 122b, and a 1-3 layer 122c. The 1-1 layer 122a, the 1-2 layer 122b, the 1-3 layer 122c, the second layer 123, and the third layer 124 may be sequentially disposed.

[0167] The 1-1 layer 122a, 1-2 layer 122b and 1-3 layer 122c, the second layer 123 and the third layer 124 of the first electrode 121-1 may be sequentially deposited and then heat-treated. After the heat treatment, the metal materials in the first layer 122-1 may be mixed together. This will be referred to below. Figure 8b Described in further detail.

[0168] Meanwhile, after the heat treatment of the first electrode 121 - 1 , a balling phenomenon may occur and voids may be generated in the first electrode 121 - 1. In particular, the balling phenomenon may occur on the second surface 121 - 1 b of the first electrode 121 - 1.

[0169] This is because the first metal (e.g., Al) included in the 1-3 layer 122c and the third metal (e.g., Au) included in the third layer 124 have different diffusion coefficients. The diffusion coefficient represents the degree of diffusion per unit time. As the diffusion coefficient increases, the diffusion speed may increase. In other words, the first metal has a greater diffusion coefficient than the third metal and may have a higher diffusion speed than the third metal. In other words, the first metal may have a characteristic of tending to diffuse toward the third layer 124.

[0170] Therefore, the first metal material may move from a partial region of the first layer 122-1 having a high ratio of the first metal to the third layer 124. As the first metal material moves, a spheroidization phenomenon may occur in certain regions of the 1-3 layer 122c, the second layer 123, and the third layer 124. In addition, a Kirkendall void, which is a vacant point from which the first metal material has moved, may be generated under the spheroidized region.

[0171] The balling phenomenon may reduce the efficiency of the semiconductor device. In other words, the current may be concentrated in the balling region. Moreover, the first electrode 121-1 may be corroded along the balling region (or the void region). This may reduce the ohmic characteristics of the first electrode 121-1. In order to prevent this, it is preferred to maintain the ohmic characteristics and minimize the generation of voids by appropriately controlling the thickness of the components of the first electrode 121, especially the 1-3 layer 122c and the second layer 123.

[0172] The first layer 122-1 may be exposed through the first insulating layer 151 and electrically coupled to the first conductive semiconductor layer 111. The first layer 122-1 may be electrically coupled to the first conductive semiconductor layer 111 through the first surface 121-1a. The first layer 122-1 may include Cr, Ti, and Al. In this case, the ohmic characteristics of the first electrode 121-1 may be controlled by Al. When the amount of Al increases, the ohmic characteristics may be improved, but the balling phenomenon may occur more frequently. Therefore, when the amount of Al exceeds an appropriate level and becomes excessive, an ohmic contact may not be formed due to an increase in the number of balling and voids.

[0173] In the first layer 122-1, the first metal layer (1-3 layer) 122c including the first metal (e.g., Al) has a thickness of 100nm to 120nm. When the thickness of the 1-3 layer 122c is less than 100nm, the ohmic characteristic may be degraded. When the thickness of the 1-3 layer 122c is greater than 120nm, a spheroidization phenomenon (voids) may occur.

[0174] Meanwhile, the thickness of the 1-3 layer 122c may be in the range of 1.5 to 2.5 times the sum of the thicknesses of the 1-1 layer 122a and the 1-2 layer 122b. When the thickness of the 1-3 layer 122c deviates from the ratio and is relatively too small or too large in the first layer 122-1, ohmic contact may not be formed.

[0175] The plurality of layers included in the first layer 122-1 may include different metal materials. For example, the 1-1 layer 122a may include Cr, and the 1-2 layer 122b may include Ti. However, the present invention is not limited thereto.

[0176] The second layer 123 may be disposed on the first layer 122-1. Specifically, the second layer 123 may be disposed on the 1-3 layer 122c. The second layer 123 may serve as a barrier between the first layer 122-1 and the third layer 124. Specifically, the second layer 123 may prevent diffusion caused by a difference in diffusion coefficient between the 1-3 layer 122c and the third layer 124. The second layer 123 may include a second metal (e.g., Ni). When the layer including Ni becomes thicker, a spheroidization phenomenon may occur with a lower frequency, but the ohmic characteristic may be reduced.

[0177] The second layer 123 may have a thickness of 45 nm to 65 nm. When the thickness of the second layer 123 is less than 45 nm, the first metal of the first layer 122-1 may diffuse toward the third layer 124, so that voids may be generated and a balling phenomenon may occur. When the thickness of the second layer 123 is greater than 65 nm, the ohmic characteristics may deteriorate.

[0178] The thickness of the second layer 123 may be in the range of 0.4 to 0.53 times the thickness of the 1-3 layer 122c. When the thickness of the second layer 123 is less than 0.4 times the thickness of the 1-3 layer 122c, a spheroidization phenomenon may occur and voids may be generated. In other words, the second layer 123 used as a barrier has a small thickness relative to the 1-3 layer 122c, and thus may not be able to properly prevent diffusion. When the thickness of the second layer 123 is greater than 0.53 times the thickness of the 1-3 layer 122c, the ohmic characteristic may be degraded. In other words, the thickness of the 1-3 layer 122c that controls the ohmic characteristic becomes relatively small, and therefore, the ohmic characteristic may be degraded.

[0179] The third layer 124 may be disposed on the second layer 123. The third layer 124 may be electrically coupled to the first conductive layer 131 through the second surface 121-1b. The third layer 124 may include Au, but the present invention is not limited thereto.

[0180] The following will refer to Figure 8b A first electrode according to a second embodiment is described.

[0181] The first electrode 121-2 is connected to the first conductive semiconductor layer 111 (see Figure 1 ) ohmic contact, and may include at least one conductive material. The first electrode 121-2 may include a plurality of layers. The first electrode 121-2 may include a first surface 121-2a in contact with the first conductive semiconductor layer 111 and a second surface 121-2b in contact with the first conductive layer 131.

[0182] The first electrode 121-2 may include a first layer 122-2, a second layer 123, and a third layer 124. The first layer 122-2 may include a first region 122d and a second region 122e.

[0183] Can be heat treated Figure 8a The first electrode 121-1 is obtained Figure 8b After the heat treatment, the first layer 122-1 (see Figure 8a ) in the metal, so that the first electrode 121-2 (see Figure 8b )'s first layer 122-2.

[0184] The first layer 122-2 may be exposed through the first insulating layer 151 and electrically coupled to the first conductive semiconductor layer 111. The first layer 122-2 may be electrically coupled to the first conductive semiconductor layer 111 through the first surface 121-2a. The first layer 122-2 may include Cr, Ti, and Al. In this case, the ohmic characteristics of the first electrode 121-2 may be controlled by Al.

[0185] The first layer 122-2 may include a first region 122d and a second region 122e. The first region 122d may be a region from the first surface 121-2a to the dotted line L in the first layer 122-2. The second region 122e may be a region from the dotted line L to the interface between the first layer 122-2 and the second layer 123.

[0186] The first region 122d and the second region 122e may each include Cr, Ti, and Al. In this case, the Al (first metal) ratio in the first region 122d may be smaller than the Al ratio in the second region 122e. Moreover, the sum of the Cr and Ti ratios in the first region 122d may be greater than the sum of the Cr and Ti ratios in the second region 122e.

[0187] This is because the first region 122d is provided in the region corresponding to the 1-1 layer 122a and the 1-2 layer 122b in the first layer 122-1 before the heat treatment (see Figure 8a ). In other words, even when the first layer 121-2 (see Figure 8a ) are diffused and mixed together by heat treatment, Cr and Ti already present in the 1-1 layer 122a and the 1-2 layer 122b may appear more in the region (first region) where the 1-1 layer 122a and the 1-2 layer 122b have been deposited.

[0188] Furthermore, before the heat treatment, the second region 122e may be disposed in a region corresponding to the 1-3 layer 122c. Figure 8a ) are diffused and mixed together by heat treatment, Al already present in the 1-3 layer 122c may appear in a relatively large amount in the region (second region) where the 1-3 layer 122c has been arranged.

[0189] The dotted line L may be located at a point where the first region 122d and the second region 122e in the first layer 122-2 are divided at a ratio of 3:7 to 6.5:3.5. In other words, the thickness ratio of the first region 122d to the second region 122e in the first layer 122-2 may be in the range of 3:7 to 6.5:3.5. This is because, as described above, the thickness of the 1-3 layer 122c is in the range of 1.5 to 2.5 times the sum of the thicknesses of the 1-1 layer 122a and the 1-2 layer 122b.

[0190] Furthermore, the ratio of the Al ratio of the first region 122d to the Al ratio of the second region 122e may be in the range of 1:1.5 to 1:2.5. This is because, as described above, before the heat treatment, the thickness of the first to third layers 122c (see Figure 8a ) is within a range of 1.5 to 2.5 times the sum of the thicknesses of the 1-1 layer 122a and the 1-2 layer 122b. In other words, this is because the thickness of the 1-3 layer 122c is greater than the sum of the thicknesses of the 1-1 layer 122a and the 1-2 layer 122b, and therefore, a large amount of Al already included in the 1-3 layer 122c is retained in the second region 122e.

[0191] The second layer 123 may be disposed on the first layer 122-2. Specifically, the second layer 123 may be disposed on the second region 122e. The second layer 123 may serve as a barrier between the first layer 122-2 and the third layer 124. Specifically, the second layer 123 may prevent diffusion caused by a difference in diffusion coefficient between a first metal (e.g., Al) included in the first layer 122-2 and a third metal (e.g., Au) included in the third layer 124. The second layer 123 may include a second metal (e.g., Ni).

[0192] The second layer 123 may have a thickness of 45 to 65 nm. When the thickness of the second layer 123 is less than 45 nm, the first metal of the first layer 122-2 may diffuse toward the third layer 124, so that voids may be generated and a balling phenomenon may occur. When the thickness of the second layer 123 is greater than 65 nm, the ohmic characteristics may deteriorate.

[0193] The third layer 124 may be disposed on the second layer 123. The third layer 124 may be electrically coupled to the first conductive layer 131 through the second surface 121-2b. The third layer 124 may include Au, but the present invention is not limited thereto.

[0194] As described above, according to the present invention, by appropriately controlling the thickness of the layer including Al (thereby controlling the ohmic characteristics) and the thickness of the layer including Ni serving as a barrier, the ohmic characteristics can be maintained, the spheroidization phenomenon can be suppressed, and the generation of voids can be minimized.

[0195] <Experimental example>

[0196] Comparison of contact resistivity, surface characteristics, and ohmic characteristics

[0197] The first electrode is formed in a structure of layer 1-1 / layer 1-2 / first metal layer (layer 1-3) / second layer / third layer. Here, Comparative Example 1, Example 1, Example 2, and Example 3 are configured by changing the thickness of the first metal layer and the second layer. The first metal layer may include Al, and the second layer may include Ni. The first electrode may be heat-treated.

[0198] Table 2 shows the thickness of Comparative Example 1, Example 1, Example 2, and Example 3 and the contact resistivity values ​​based on transmission line measurement (TLM).

[0199] [Table 2]

[0200]

[0201] Figures 9a to 9d The balling phenomenon observed in different configurations of the first electrode in the semiconductor device according to the embodiment of the present invention is shown. Figure 9a The observation results of Comparative Example 1 are shown. Figure 9b The observation results of Example 1 are shown. Fig.9c The observation results of Example 2 are shown. Figure 9d The observation results of Example 3 are shown. Fig.10 It shows the TLM-based Figures 9a to 9d A graph showing the voltage and current values ​​of the first electrode. Fig.10 In the graph of , a higher slope indicates low resistance and can indicate good ohmic characteristics. Referring to Table 2, Comparative Example 1, Example 1, Example 2, and Example 3 are compared with each other.

[0202] In the case of Comparative Example 1, the thickness of the first metal layer is 130 nm, and therefore, the balling phenomenon observed is significantly more than that of Examples 1 to 3 (see Figure 9a ). Referring to Table 2, it can be seen that the contact resistivity value of Comparative Example 1 is relatively greater than the contact resistivity values ​​of Examples 2 and 3. Fig.10 It can be seen that the ohmic characteristic of Comparative Example 1 is not as good as those of Examples 1 and 2, but is significantly better than that of Example 3. However, spheroidization is often observed in Comparative Example 1, and therefore, Comparative Example 1 is not suitable for the first electrode.

[0203] In the case of Example 1, spheroidization was hardly observed, and thus it can be seen that the surface properties were very good (see Figure 9b ). At the same time, Example 1 and Comparative Example 1 have the largest contact resistivity. However, Fig.10 , it can be seen that the ohmic characteristic of Example 1 is good, which is inferior to that of Example 3. Therefore, the contact resistivity of Example 1 is slightly higher than that of Examples 2 and 3, but Example 1 can be used as the first electrode because of its good surface characteristics and ohmic characteristics.

[0204] In the case of Example 2, the first metal layer (Al) is configured to be thicker than the first metal layer of Example 1. Since Al is a metal that controls ohmic characteristics, it can be seen that the contact resistivity of Example 2 is significantly lower than that of Example 1 (see Table 2). Fig.10 , it can be seen that the ohmic characteristic of Example 2 is the best. However, since the first metal layer becomes thicker, the balling phenomenon may occur more frequently than in Example 1 (see Fig.9c ). Therefore, although Example 2 shows slightly inferior surface characteristics to Examples 1 and 3, Example 2 shows the best results in terms of contact resistivity and ohmic characteristics, and thus can be used as a first electrode.

[0205] In the case of Example 3, the second metal layer (Ni) is configured to be thicker than the second metal layer of Example 2. Since Ni serves as a barrier to prevent metal diffusion, it can be seen that the spheroidization phenomenon is hardly observed in Example 3 compared with Example 2 (see Figure 9d However, since the second layer becomes thicker, it can be seen that the contact resistivity increases (see Table 2) and the ohmic characteristics deteriorate compared with Example 2 (see Fig.10 ). Therefore, although Example 3 shows slightly inferior contact resistivity and ohmic characteristics than Examples 1 and 2, Example 3 can be used as a first electrode due to good surface characteristics.

[0206] TLM results according to various modifications of the first electrode

[0207] In Table 3, Rc, Rs and σ of the first electrode of various modifications are calculated by TLM. c Compared with each other. The first electrode may have a structure of layer 1-1 / layer 1-2 / first metal layer (layer 1-3) / second layer / third layer. The first electrode may be heat-treated. The first metal layer may include Al, and the second metal layer may include Ni. In addition, layer 1-1 may include Cr, layer 1-2 may include Ti, and the third layer may include Au.

[0208] R1, R2 and R3 are first electrodes according to an embodiment of the present invention, and T1, T2-1, T2-2, T3-1, T3-2 and T3-3 are modified first electrodes. Here, the intermediate layer refers to a layer between the second layer and the third layer. Rc, Rs and σ c They represent contact resistance, surface resistance and contact resistivity respectively. As resistance increases, ohmic characteristics decrease.

[0209] [Table 3]

[0210] Al(nm) Ni(nm) Middle layer structure Rc Rs <![CDATA[σ c ]]> R1 120 50 - 11.38 52.79 2.21.E-03 T1 300 100 Cu / Ni 1299.39 -187.99 -8.08.E+00 R2 120 50 - 11.20 56.25 2.01.E-03 T2-1 120 100 Ti / Ni / Ti / Cu 12102.89 2556.98 5.16.E+01 T2-2 120 5 Cu 23.63 57.53 8.73.E-03 R3 120 50 - 14.48 66.88 2.82.E-03 T3-1 60 50 - 269.23 227.86 2.86.E-01 T3-2 90 50 - 20.80 67.17 5.80.E-03 T3-3 150 50 - 10.23 46.46 2.03.E-03

[0211] In the case of T1, the first metal layer (Al) is formed to have a thickness of 300nm to improve the ohmic characteristics, and the second layer (Ni) is formed to have a thickness of 100nm to serve as a potential barrier. Moreover, an intermediate layer is additionally formed of Cu / Ni between the second layer and the third layer. Cu can serve as a potential barrier. However, in this case, the excess Al and Ni significantly increase the contact resistance value compared to R1. Therefore, it can be expected that the ohmic characteristics will not improve but deteriorate. In particular, the surface resistance and the contact resistivity have negative values, and therefore, it can be seen that no ohmic contact is formed in T1. Therefore, T1 is not suitable for the first electrode.

[0212] In the case of T2-1, the first metal layer has the same thickness as R2. In T2-1, the second layer is formed to have a thickness of 100 nm, and an intermediate layer is additionally formed to observe whether the barrier effect is improved compared with R2. However, since the thickness of the second layer and the intermediate layer is too large, ohmic contact may not be formed. In other words, the contact resistance, surface resistance, and contact resistivity of T2-1 are significantly greater than those of R2. Therefore, T2-1 is not suitable for the first electrode.

[0213] In the case of T2-2, the thickness of the second layer is reduced and a Cu barrier layer is added to the intermediate layer. However, compared with the contact resistance of R2, the contact resistance of T2-2 increases and the ohmic contact deteriorates. Therefore, T2-2 is not suitable for the first electrode.

[0214] In the case of T3-1 and T3-2, the first metal layer is formed to have a thickness of 60nm and 90nm, respectively. It can be seen that the contact resistance, surface resistance and contact resistivity of T3-1 are significantly increased compared with those of R3. In other words, in T3-1, the thickness of the first metal layer is less than the thickness of the second layer, so that ohmic contact may not be formed. Moreover, it can be seen that the contact resistance of T3-2 increases compared with the contact resistance of R3. In other words, in T3-2, the thickness of the first metal layer is less than the thickness of the second layer in T3-1 but greater than the thickness of the first layer. Therefore, the ohmic characteristics may deteriorate. Therefore, since the thickness of the first metal layer of T3-1 and T3-2 is less than the thickness of the second layer, T3-1 and T3-2 are not suitable for the first electrode.

[0215] In the case of T3-3, the first metal layer is formed to have a thickness of 150 nm. In this case, it can be seen that the contact resistance and the surface resistance are both reduced compared with those of R3. However, Figure 9a , it can be expected that spheroidization will occur frequently and many voids will be generated. In other words, the contact resistance and surface resistance of T3-3 are both low, and therefore, the ohmic characteristics can be improved. However, T3-3 is not suitable for the first electrode due to its poor surface characteristics.

[0216] Fig.11 is a conceptual diagram of a semiconductor package according to an embodiment of the present invention.

[0217] The semiconductor device may be configured as a package and used for curing resin, resist, spin-on dielectric (SOD) or spin-on glass (SOG). Alternatively, the semiconductor device may be used for medical treatment or health care or for disinfection in air purifiers, water purifiers, etc.

[0218] Reference Fig.11, the semiconductor device package may include: a body 2 in which a recessed groove 3 is formed, a semiconductor device 1 disposed in the body 2, and a pair of lead frames 5a and 5b disposed in the body and electrically coupled to the semiconductor device 1. The semiconductor device 1 may include all of the above elements.

[0219] The body 2 may include a material or coating that reflects ultraviolet light. The body 2 may be formed by stacking a plurality of layers 2a, 2b, 2c, 2d, and 2e. The plurality of layers 2a, 2b, 2c, 2d, and 2e may be formed of the same material, or may include different materials.

[0220] The recessed groove 3 may be formed to gradually become wider as being farther away from the semiconductor device, and a step 3 a may be formed in the inclined surface.

[0221] The transparent layer 4 may cover the concave groove 3. The transparent layer 4 may be formed of a glass material, but is not necessarily limited thereto. The transparent layer 4 may be formed of any material that effectively transmits ultraviolet light. The interior of the concave groove 3 may be an empty space.

[0222] The semiconductor device can be used as a light source of a lighting system, a light source of an image display device, or a light source of a lighting device. In other words, the semiconductor device can be disposed in a housing and applied to various electronic devices that provide light. For example, when a semiconductor device and a red-green-blue (RGB) fluorescent substance are used in combination, white light with a high color rendering index (CRI) can be achieved.

[0223] The semiconductor device described above can constitute a light emitting device package and can be used as a light source of a lighting system. For example, the semiconductor device can be used as a light source of an image display device or a light source of a lighting device.

[0224] When the semiconductor device is used as a backlight unit of an image display device, the semiconductor device can be used as an edge-type backlight unit or a direct-type backlight unit. When the semiconductor device is used as a light source of an illumination device, the semiconductor device can be used as a lamp or a bulb-type light source. Alternatively, the semiconductor device can be used as a light source of a mobile terminal.

[0225] In addition to the above-mentioned light emitting diodes, the light emitting device may be a laser diode.

[0226] Similar to a light emitting diode, a laser diode may include a first conductive semiconductor layer and a second conductive semiconductor layer having the above structure. The laser diode uses an electroluminescence phenomenon in which light is emitted when current flows after a p-type first conductive semiconductor and an n-type second conductive semiconductor are bonded, but the laser diode has differences in the directionality and phase of the emitted light. In other words, the laser diode can emit light (monochromatic light beam) having a specific wavelength in the same phase and in the same direction using stimulated emission phenomena, enhanced interference phenomena, and the like. Due to these characteristics, the laser diode can be used in optical communications or medical equipment, semiconductor process equipment, and the like.

[0227] An example of a light receiving device may be a photodetector, which is a transducer for detecting light and converting the intensity of light into an electrical signal. The light receiving device may be a photocell (silicon or selenium), a photoconductive device (cadmium sulfide or cadmium selenide), a photodiode (e.g., a photodiode (PD) having a peak wavelength in a visible blind spectral region or a true blind spectral region), a phototransistor, a photomultiplier tube, a phototube (vacuum or gas sealed), an infrared (IR) detector, etc., but the embodiment is not limited thereto.

[0228] Generally, semiconductor devices such as photodetectors can be manufactured using direct bandgap semiconductors with high light conversion efficiency. Alternatively, there are various photodetector structures, among which the most common photodetectors include pin-type photodetectors using pn junctions, Schottky-type photodetectors using Schottky junctions, metal-semiconductor-metal (MSM)-type photodetectors, and the like.

[0229] Like a light emitting device, a photodiode may include a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer having the above structure, and may be configured in a pn junction or a pin structure. The photodiode is operated by applying a reverse bias or a zero bias. When light is incident on the photodiode, electrons and holes are generated and current flows. In this case, the current may be almost proportional to the intensity of the light incident on the photodiode.

[0230] A photovoltaic cell or solar cell is a photodiode that can convert light into electric current. Like a light emitting device, a solar cell may include a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer having the above structure.

[0231] Moreover, the photodiode can be used as a rectifier of an electronic circuit by using the rectification characteristics of an ordinary diode of a pn junction, and can be applied to a very high frequency circuit and then applied to an oscillation circuit, etc.

[0232] The semiconductor devices described above are not only implemented with semiconductors, but may also include metal materials in some cases. For example, semiconductor devices such as light-receiving devices may be implemented with at least one of Ag, Al, Au, In, Ga, N, Zn, Se, P, and As, and may be implemented using semiconductor materials doped with p-type dopants or n-type dopants or intrinsic semiconductor materials.

[0233] Although the embodiments are mainly described above, they are only examples and do not limit the present invention. It will be appreciated by those skilled in the art that several modifications and applications not shown above may be made without departing from the essential features of the embodiments. For example, each element specifically represented in the embodiments may be implemented in a modified manner. It should be understood that the differences associated with such changes and applications are included within the scope of the present invention defined in the following claims.

Claims

1. A semiconductor device, characterized in that: include: A light emitting structure comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first electrode electrically coupled to the first conductive semiconductor layer; as well as a second electrode electrically coupled to the second conductive semiconductor layer, Wherein, the first electrode comprises a first layer, a second layer and a third layer, The first layer includes a 1-1 layer, a 1-2 layer, and a first metal layer, wherein the 1-2 layer is disposed between the 1-1 layer and the first metal layer. The first metal layer includes a first metal, The second layer is disposed between the first metal layer and the third layer, a diffusion coefficient of the first metal is greater than a diffusion coefficient of a third metal included in the third layer, The thickness of the first metal layer is in the range of 1.5 to 2.5 times the sum of the thicknesses of the 1-1 layer and the 1-2 layer, and The thickness of the second layer is in the range of 0.4 to 0.53 times the thickness of the first metal layer.

2. The semiconductor device according to claim 1, wherein: The 1-1 layer includes Cr, and the 1-2 layer includes Ti.

3. The semiconductor device according to any one of claims 1 to 2, characterized in that: The thickness of the first metal layer is 100 nm to 120 nm.

4. The semiconductor device according to any one of claims 1 to 2, characterized in that: The second layer has a thickness of 45 nm to 65 nm.

5. The semiconductor device according to any one of claims 1 to 2, characterized in that: The first metal is Al, and the third metal is Au.

6. The semiconductor device according to any one of claims 1 to 2, characterized in that: Also includes: a reflective layer, disposed on the second electrode; and The cover layer is disposed on the reflective layer and includes a plurality of layers.

7. The semiconductor device according to any one of claims 1 to 2, characterized in that: The light emitting structure further includes a plurality of grooves passing through the second conductive semiconductor layer and the active layer and extending to a partial region of the first conductive semiconductor layer, and the first electrode is disposed in the plurality of grooves.

8. A semiconductor device package, characterized in that: A semiconductor device comprising any one of claims 1 to 7.

Images