JP5172388B2 - Nitride-based semiconductor light-emitting diode and manufacturing method thereof - Google Patents

Description

  The present invention relates to a nitride semiconductor light emitting diode and a method for manufacturing the same.

  Conventionally, as an edge emitting type semiconductor laser element, a resonator element end face (light emitting surface) and a reflecting surface for reflecting laser emitted light to the outside are integrated with a semiconductor element layer using a gallium arsenide based semiconductor material. A semiconductor laser device formed in the above and a manufacturing method thereof are disclosed (for example, see Non-Patent Document 1).

  In the semiconductor laser device disclosed in Non-Patent Document 1, a cavity facet on the light emitting surface side is formed by ion beam etching technology on a gallium arsenide-based semiconductor element layer uniformly stacked on a substrate, A reflecting surface (inclined end surface) extending in a direction inclined by about 45 ° with respect to the resonator end surface is formed at a position spaced apart from the resonator end surface by a predetermined distance. Thereby, the laser emission light from the light emitting layer is reflected in a direction substantially perpendicular to the substrate by the reflecting surface and can be taken out to the outside.

Appl. Phys. Lett. 48 (24), 16 June 1986, p. 1675-1677

  However, in the semiconductor laser element disclosed in Non-Patent Document 1, a reflecting surface (tilted end surface) inclined by about 45 ° with respect to the resonator end surface is formed in order to extract laser light in a direction substantially perpendicular to the substrate. On the other hand, there is no disclosure or suggestion about the plane orientation of the reflecting surface. Generally, when an end face is formed in a semiconductor element layer by using dry etching such as ion beam etching, a fine uneven shape is formed on the end face by etching. Therefore, in the semiconductor laser element disclosed in Non-Patent Document 1, it is considered that the reflection surface has a fine uneven shape. In this case, a part of the laser light emitted from the resonator end face (light emitting surface) is scattered by the reflecting surface, so that the light emission efficiency of the semiconductor laser element is lowered. For this reason, when the element structure of the semiconductor laser element disclosed in Non-Patent Document 1 is applied to a light-emitting diode, a part of light emitted from the light-emitting portion (light-emitting layer) is scattered on the reflection surface. There is a problem in that the luminous efficiency of the light source is reduced. Moreover, in the said nonpatent literature 1, since it uses dry etching in the process of forming a reflective surface, it is thought that a light emitting part (light emitting layer) vicinity tends to be damaged. Also by this, the light extraction efficiency from the light emitting part is lowered, and the above problem becomes more remarkable.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a nitride-based semiconductor light-emitting diode capable of suppressing a decrease in luminous efficiency and a method for manufacturing the same. Is to provide.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, a nitride-based semiconductor light-emitting diode according to a first aspect of the present invention includes a first side formed of a (000-1) plane, and a second side in a region facing the first side. And a support substrate bonded to the nitride semiconductor layer.

  In the nitride semiconductor light emitting diode according to the first aspect of the present invention, as described above, the nitride semiconductor semiconductor layer including the first side surface composed of the (000-1) plane has the plane orientation described above. Since the first side surface has flatness, the light emitted from the light emitting layer inside the nitride-based semiconductor layer is scattered on the first side surface, unlike the case where it passes through the end surface on which a fine uneven shape such as etching is formed. Is suppressed. That is, the light emitted from the light emitting layer is emitted toward the outside of the element in a state where a decrease in the amount of light accompanying scattering or the like is suppressed. As a result, it is possible to suppress a decrease in the light emission efficiency of the light emitting diode.

  In the nitride-based semiconductor light-emitting diode according to the first aspect, preferably, the nitride-based semiconductor layer and the support substrate are bonded via a bonding layer. If comprised in this way, a nitride-type semiconductor layer and a support substrate can be reliably joined by a joining layer.

  In the nitride-based semiconductor light-emitting diode according to the first aspect, preferably, the first side surface and the second side surface are formed of a crystal growth surface of the nitride-based semiconductor layer. If comprised in this way, the two types of growth surface (end surface) of the said 1st side surface and the 2nd side surface can each be formed simultaneously with the crystal growth of a nitride type semiconductor layer.

  In the nitride-based semiconductor light-emitting diode according to the first aspect, preferably, the second side surface is a {A + B, A, −2A−B, 2A + B} plane (where A ≧ 0 and B ≧ 0, and An integer in which at least one of A and B is not 0). With this configuration, for example, the surface of the growth layer of the nitride-based semiconductor layer (mainly when the side surface (end surface) not corresponding to the {A + B, A, −2A−B, 2A + B} plane is formed on the growth substrate (mainly The surface (main surface) of the growth layer in the case where the second side surface composed of {A + B, AB, -2A, 2A + B} plane is formed on the growth substrate is surely flat compared to the surface). Can be formed. Further, the {A + B, A, -2A-B, 2A + B} plane has a slower growth rate than the main surface of the nitride-based semiconductor layer, so that the second side surface can be easily formed by crystal growth.

  In the nitride-based semiconductor light-emitting diode according to the first aspect, preferably, at least one of the first side surface and the second side surface is formed to be inclined with respect to the main surface of the nitride-based semiconductor layer. . With this configuration, when the region where the first side surface and the second side surface of the nitride-based semiconductor layer face each other is formed so as to expand toward the light extraction side, LED light from the light emitting layer is formed. Can be easily extracted not only through the light extraction surface of the nitride-based semiconductor layer but also through the first side surface or the second side surface inclined with respect to the main surface of the nitride-based semiconductor layer. On the other hand, when the region where the first side surface and the second side surface of the nitride-based semiconductor layer face each other is formed so as to narrow toward the light extraction side, the LED light from the light-emitting layer is transmitted to the nitride-based semiconductor. In addition to direct extraction from the light extraction surface of the layer, it can be reflected and extracted by the first side surface or the second side surface inclined with respect to the main surface of the nitride-based semiconductor layer. Thereby, the luminous efficiency of the nitride-based semiconductor light-emitting diode can be further improved.

  The method for manufacturing a nitride-based semiconductor light-emitting diode according to the second aspect of the present invention includes a step of forming a recess on the main surface of the growth substrate, a light-emitting layer on the main surface of the growth substrate, and one of the recesses. A nitride-based semiconductor layer including a first side surface having a (000-1) plane starting from the inner side surface of the first side surface and a second side surface starting from the other inner side surface of the recess in a region facing the first side surface A step of growing, a step of bonding the support substrate to the nitride-based semiconductor layer, and a step of removing the growth substrate.

  In the method for manufacturing a nitride-based semiconductor light-emitting diode according to the second aspect of the present invention, as described above, the step of forming a recess in the main surface of the growth substrate and one of the recesses on the main surface of the growth substrate. A step of growing a nitride-based semiconductor layer including a first side surface having a (000-1) plane starting from the inner side surface, for example, with respect to a nitride-based semiconductor layer formed on a growth substrate Unlike the case of forming an end face having a fine concavo-convex shape by ion beam etching or the like, good flatness is obtained on the first side face having the above plane orientation. As a result, the light emitted from the light emitting layer inside the nitride-based semiconductor layer is suppressed from being scattered at the first side surface, so that the light emitted from the light emitting layer is directed toward the outside of the device in a state where the decrease in the amount of light is suppressed. Emitted. As a result, a light emitting diode in which a decrease in light emission efficiency is suppressed can be formed. In addition, nitriding including a first side surface composed of a (000-1) plane starting from one inner side surface of the recess and a second side surface starting from the other inner side surface of the recess on the main surface of the growth substrate By providing the step of growing the physical semiconductor layer, the first side surface and the second side surface of the nitride based semiconductor layer are not formed by dry etching or the like, so that the light emitting layer or the like is hardly damaged in the manufacturing process. Thus, a light emitting diode with improved light extraction efficiency from the light emitting layer can be formed. In addition, since the etching process or the like is not required for forming the first side surface and the second side surface, it is possible to prevent the manufacturing process of the nitride semiconductor light emitting diode from becoming complicated.

  A step of forming a recess on the main surface of the growth substrate; a first side surface comprising a (000-1) plane starting from one inner surface of the recess on the main surface of the growth substrate; and the other side of the recess. And a step of growing a nitride-based semiconductor layer including a second side surface starting from the inner side surface of the substrate, when the nitride-based semiconductor layer is crystal-grown on the growth substrate, the upper surface ( Growth in which the first side surface starting from one inner side surface of the recess and the second side surface starting from the other inner side surface of the recess are formed rather than the growth rate at which the main surface of the nitride-based semiconductor layer grows. Since the speed is low, the upper surface (main surface) of the growth layer grows while maintaining flatness. As a result, the flatness of the surface of the semiconductor layer having the light emitting layer can be further improved as compared with the growth layer surface of the nitride-based semiconductor layer in the case where the end surface composed of the first side surface and the second side surface is not formed. it can. The reason for this is considered as follows.

  Surfaces with a slow growth rate such as the (000-1) plane and the {A + B, A, -2A-B, 2A + B} plane have a small surface energy, while examples of a surface with a high growth rate include (1-100) Surfaces are considered to have a large surface energy. Since the surface during crystal growth is more stable when the surface energy is small, the surface energy is smaller than that of the (1-100) plane when performing crystal growth with only the (1-100) plane as the growth plane. Surfaces other than the (1-100) surface are likely to appear. As a result, the flatness of the growth surface (main surface) tends to be impaired. On the other hand, in the present invention, for example, the (000-1) plane or {A + B, A, -2A-B, 2A + B} plane having a smaller surface energy than the (1-100) plane grown as the main surface is formed. Since the plane ((1-100) plane) is grown, the surface energy of the growth plane (main surface) can be reduced compared to the case where crystal growth is performed using only the (1-100) plane as the growth plane. it can. This is thought to improve the flatness of the growth surface.

  In the method for manufacturing a nitride semiconductor light emitting diode according to the second aspect, the growth substrate is preferably made of a nitride semiconductor. If comprised in this way, the nitride which has the 1st side surface which consists of a (000-1) plane, and a 2nd side surface using the crystal growth of a nitride-type semiconductor layer on the growth substrate which consists of nitride-type semiconductors A semiconductor layer can be easily formed.

In the method for manufacturing a nitride semiconductor light emitting diode according to the second aspect, preferably, the growth substrate includes a base substrate and a base layer formed on the base substrate and made of AlGaN. If the lattice constants, respectively, and _{c 1} and _{c 2,} has a relation of c 1> _{c 2,} first and second side surfaces, respectively, the main underlying layers (0001) of the surface and the underlying substrate It is formed starting from the inner surface of the crack formed so as to extend substantially parallel to the surface. With this configuration, when forming the base layer made of AlGaN on the base substrate, the lattice constant c ₂ of the base layer is smaller than the lattice constant c _{1 of the} base substrate (c ₁ > c ₂ ). tensile stress is caused inside the underlayer in response to the lattice constant c ₁ on the substrate side. As a result, when the thickness of the underlayer is equal to or greater than a predetermined thickness, the underlayer cannot withstand this tensile stress and cracks are formed in the underlayer. As a result, the inner side surface (one inner side surface of the concave portion) composed of the (000-1) surface serving as a reference for forming the first side surface ((000-1) surface) of the nitride-based semiconductor layer on the underlayer. Can be easily formed on the base layer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view for explaining a schematic configuration of an LED chip according to the present invention. Before describing a specific embodiment of the present invention with reference to FIG. 1, a schematic configuration of an LED chip according to the present invention will be described using an LED chip 10 as an example.

  As shown in FIG. 1, the LED chip 10 has a light emitting layer 2 formed on a first semiconductor 1. A second semiconductor 3 is formed on the light emitting layer 2. Further, in each layer of the first semiconductor 1, the light emitting layer 2, and the second semiconductor 3, a side surface 10a and a side surface 10b inclined with respect to the main surface of each layer are formed. Here, one of the side surface 10a or the side surface 10b is composed of (000-1) planes. Further, the other of the side surface 10a or the side surface 10b is a {A + B, A, −2A−B, 2A + B} plane (where A ≧ 0 and B ≧ 0, and at least one of A and B is 0) Preferably an integer). A first electrode 4 is formed on the lower surface of the first semiconductor 1, and a second electrode 5 is formed on the second semiconductor 3. A support substrate 6 is bonded to the second electrode 5. The first semiconductor 1 is an example of the “growth substrate” and “nitride-based semiconductor layer” of the present invention, and the light-emitting layer 2 and the second semiconductor 3 are respectively “nitride-based semiconductor layers” of the present invention. Is an example.

  Further, as the support substrate 6, a conductive substrate may be used, or an insulating substrate may be used. As the substrate having conductivity, for example, a metal plate such as Cu-W, Al and Fe-Ni, a semiconductor substrate such as single crystal Si, SiC, GaAs and ZnO, or a polycrystalline AlN substrate is used. May be. Further, a conductive resin film in which conductive fine particles such as metal are dispersed, a composite material of a metal and a metal oxide, or the like, or carbon composed of a graphite particle sintered body impregnated with a metal may be used. Alternatively, a metal composite material may be used. When a conductive substrate is used, an electrode may be formed on the surface (upper surface) opposite to the side where the semiconductor layer is bonded. Further, a semiconductor substrate may be used as the support substrate 6.

  Moreover, it is preferable that there is a bonding layer between the support substrate 6 and the second electrode 5. As the bonding layer, a layer made of a material such as solder or conductive paste can be used. As the solder, solder made of AuSn, InSn, SnAgCu, SnAgBi, SnAgCuBi, SnAgBiIn, SnZn, SnCu, SnBi, SnZnBi, or the like can be used.

  Here, generally, a light emitting layer 2 having a band gap smaller than the band gap of the first semiconductor 1 and the second semiconductor 3 is formed between the first semiconductor 1 and the second semiconductor 3 to form a double heterostructure. By forming, carriers can be easily confined in the light emitting layer 2 and the light emission efficiency of the LED chip 10 can be improved. Further, by making the light emitting layer 2 have a single quantum well structure or a multiple quantum well (MQW) structure, it is possible to further improve the light emission efficiency. In the case of this quantum well structure, since the thickness of the well layer is small, it is possible to suppress deterioration of the crystallinity of the well layer even when the well layer has strain. In addition, even if the well layer has a compressive strain in the in-plane direction of the main surface 2a of the light emitting layer 2 or a tensile strain in the in-plane direction, the deterioration of crystallinity is suppressed. Is done. The light emitting layer 2 may be undoped or doped.

  In the pn junction type LED chip 10, the first semiconductor 1 and the second semiconductor 3 have different conductivity. The first semiconductor 1 may be p-type and the second semiconductor 3 may be n-type, or the first semiconductor 1 may be n-type and the second semiconductor 3 may be p-type.

  The first semiconductor 1 and the second semiconductor 3 may include a clad layer (not shown) having a band gap larger than that of the light emitting layer 2. The first semiconductor 1 and the second semiconductor 3 may each include a cladding layer and a contact layer (not shown) in order from the light emitting layer 2 side. In this case, the contact layer preferably has a smaller band gap than the cladding layer.

  The first semiconductor 1, the light emitting layer 2, and the second semiconductor 3 are formed of a nitride semiconductor layer having a Wurtz structure made of AlN, InN, BN, TlN, and a mixed crystal thereof. For example, as the light emitting layer 2 of the quantum well, GaInN can be used as the well layer, and AlGaN, GaN, and GaInN having a larger band gap than the well layer can be used as the barrier layer. Moreover, GaN and AlGaN can be used for the cladding layer and the contact layer.

  Further, the first electrode 4 may be formed in a partial region on the first semiconductor 1. Moreover, it is preferable that the 1st electrode 4 has translucency.

  FIG. 2 is a diagram showing the crystal orientation of the nitride-based semiconductor and the range in the normal direction of the main surface of the growth substrate when a semiconductor light emitting device is formed using the manufacturing process of the present invention. Next, with reference to FIG. 2, the plane orientation of the semiconductor layer and the plane orientation of the growth substrate when a nitride-based semiconductor having a wurtz structure or 2H—SiC is used as the growth substrate will be described. .

  As shown in FIG. 2, the normal direction of the main surface 7a of the semiconductor layer or the growth substrate 7 is a line 300 ([C + D, C] connecting the [11-20] direction and the [10-10] direction, respectively. , -2C-D, 0] direction (C ≧ 0 and D ≧ 0, and at least one of C and D is not 0)) and [11-20] direction and substantially [11 −2-5] line 400 ([1, 1, −2, −E] direction (0 ≦ E ≦ 5)), and [10-10] direction and approximately [10-1-4]. Line 500 ([1, −1, 0, −F] direction (0 ≦ F ≦ 4)), and approximately [11-2-5] direction and approximately [10-1-4] direction. Line 600 ([G + H, G, −2G−H, −5G−4H] direction (G ≧ 0 and H ≧ 0, and at least one of G and H) It is in the range (hatched region by hatching) enclosed by an integer)) is not zero.

  3 to 5 are cross-sectional views for explaining a schematic manufacturing process of the LED chip according to the present invention. Next, a schematic manufacturing process of the LED of the present invention will be described with reference to FIGS. 1 and 3 to 5.

  First, as shown in FIG. 3, after the release layer 8 is formed on the upper surface of the growth substrate 7 in which a plurality of recesses 7a extending in a predetermined direction is formed, the first semiconductor 1, the light emitting layer 2 and the second semiconductor layer 1 are formed. The semiconductor 3 is crystal-grown sequentially. At this time, a buffer layer (not shown) may be formed between the growth substrate 7 (peeling layer 8) and the first semiconductor 1. Thereafter, the second electrode 5 is formed on the second semiconductor 3. In this way, the LED element portion 9 is formed.

  The release layer 8 includes a layer that is easily removed as compared with the semiconductor layers (the first semiconductor 1, the light emitting layer 2, and the second semiconductor 3) and a layer that is easily mechanically separated. Examples of the layer that is easily removed include, for example, a material having a lower melting point and boiling point than the semiconductor layer, a material that is easily decomposed compared to the semiconductor layer, a material that is easily dissolved compared to the semiconductor layer, and the semiconductor layer. There is a layer made of a material that reacts easily.

Further, when the semiconductor layer is made of a nitride semiconductor having a wurtzite structure, the growth substrate 7 can be a nitride semiconductor substrate or a heterogeneous substrate. As the heterogeneous substrate that is not a nitride-based semiconductor, for example, an α-SiC substrate having a hexagonal structure and a rhombohedral structure, a GaAs substrate, a GaP substrate, an InP substrate, a Si substrate, a sapphire substrate, a spinel substrate, and a LiAlO ₂ substrate are used. It is possible. In addition, an r-plane ((1-102) plane) sapphire substrate on which a nitride-based semiconductor whose main surface is the a-plane ((11-20) plane), an a-plane or an m-plane ((1-100) It is also possible to use an a-plane SiC substrate, an m-plane SiC substrate, or the like on which a nitride-based semiconductor whose main surface is ()) is previously grown. It is also possible to use a (100) plane substrate such as a LiAlO ₂ or LiGaO ₂ substrate on which a nitride-based semiconductor having an m-plane as a main surface is previously grown. By using a nitride semiconductor substrate, a nitride semiconductor layer having the best crystallinity can be obtained.

  Thereafter, as shown in FIG. 4, the LED element portion 9 is bonded to the support substrate 6. Then, as shown in FIG. 5, the LED element portion 9 is peeled from the growth substrate 7. At this time, in FIG. 5, laser irradiation is performed from the lower surface side of the growth substrate 7 toward the peeling layer 8 (indicated by a broken line), and the peeling layer 8 is evaporated to peel off the LED element portion 9 from the growth substrate 7. An example is shown. Finally, as shown in FIG. 1, the first electrode 4 is formed on the lower surface of the first semiconductor 1. In this way, the LED chip 10 is formed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 6 is a cross-sectional view illustrating the structure of the LED chip according to the first embodiment of the present invention. 7 to 9 are a plan view and a cross-sectional view for explaining a manufacturing process of the LED chip according to the first embodiment shown in FIG. First, the structure of the LED chip 30 according to the first embodiment will be described with reference to FIGS. 6 and 9.

  The LED chip 30 according to the first embodiment is made of a nitride semiconductor having a wurtzite structure having an a-plane ((11-20) plane) as a main surface. Moreover, the shape of the LED chip 30 has a shape such as a square shape, a rectangular shape, a rhombus, or a parallelogram when viewed in plan (as viewed from the upper surface side of the LED chip 30).

Further, the LED chip 30 has the light emitting element layer 12 formed as shown in FIG. The light emitting element layer 12 includes an n-type cladding layer 13 made of n-type Al _0.03 Ga _0.97 N having a thickness of about 3 μm, and Ga _0.7 In _0.3 N having a thickness of about 2 nm. A light emitting layer 14 having an MQW structure in which a well layer (not shown) made of and a barrier layer (not shown) made of Ga _0.9 In _0.1 N are stacked is formed. A p-type cladding layer 15 that also serves as a p-type contact layer made of p-type GaN having a thickness of about 0.2 μm is formed on the light emitting layer 14. The light emitting element layer 12, the n-type cladding layer 13, the light emitting layer 14, and the p-type cladding layer 15 are examples of the “nitride-based semiconductor layer” in the present invention.

  Here, in the first embodiment, from the n-type cladding layer 13 to the p-type cladding layer 15, the crystal growth surface 12 a composed of the (000-1) plane of the light emitting element layer 12 and the crystal composed of the (11-22) plane. A plurality of recesses 20 (see FIG. 9) are formed by the growth surface 12b. The crystal growth surface 12a and the crystal growth surface 12b are examples of the “first side surface” and the “second side surface” of the present invention, respectively. Further, as shown in FIG. 9, the crystal growth surface 12a takes over the inner side surface 21a composed of the (000-1) plane of the groove portion 21 formed in advance on the main surface of the n-type GaN substrate 11 during the manufacturing process described later. Further, the n-type GaN substrate 11 is formed so as to extend in a direction substantially perpendicular to the main surface ([11-20] direction). The n-type GaN substrate 11 is an example of the “growth substrate” in the present invention. As shown in FIG. 9, the crystal growth surface 12 b is an inclined surface starting from the inner side surface 21 b of the groove portion 21, and is formed to make an obtuse angle with respect to the upper surface (main surface) of the light emitting element layer 12. ing. The groove portion 21 and the inner side surface 21a are examples of the “recessed portion” and “one inner side surface of the recessed portion” of the present invention, respectively.

As shown in FIG. 6, an n-side translucent electrode 16 made of ITO is formed on the lower surface of the n-type cladding layer 13. A pad electrode 17 made of Au is formed in a partial region on the n-side translucent electrode 16. In addition, in the recess 20 (see FIG. 9), an insulating film 22 such as SiO ₂ that is transparent to the emission wavelength is formed to have a predetermined thickness. Then, a Pt layer having a thickness of about 5 nm and an Ag having a thickness of about 200 nm are arranged in order from the p-type cladding layer 15 so as to cover the upper surface of the substantially V-shaped insulating film 22 and the upper surface of the p-type cladding layer 15. A p-side electrode 18 composed of a layer and a W layer having a thickness of about 100 nm is formed. The p-side electrode 18 has a function of reflecting the light emitted from the light emitting layer 14 to the n-side translucent electrode 16 side by including the Ag layer. Further, a support substrate 32 made of CuW having a thickness of about 100 μm is joined to the p-side electrode 18 via a joining layer 33 made of AuSn.

  Next, a manufacturing process of the LED chip 30 according to the first embodiment will be described with reference to FIGS.

  First, as shown in FIG. 7, a width of about 5 μm in the [0001] direction (A direction) is formed on the main surface composed of the a-plane ((11-20) plane) of the n-type GaN substrate 11 using an etching technique. A plurality of grooves 21 having W1 and a depth of about 2 μm and extending in the [1-100] direction (B direction) are formed. In FIG. 7, a thick hatched portion is a region etched as the groove portion 21. The groove portions 21 are formed in a stripe shape in the A direction at a period of about 50 μm (= W1 + L1 (L1 = about 45 μm)).

  Here, in the manufacturing process of the first embodiment, as shown in FIG. 8, the groove portion 21 is made of a (000-1) plane substantially perpendicular to the (11-20) plane of the n-type GaN substrate 11. An inner side surface 21a and an inner side surface 21b made of a (0001) plane substantially perpendicular to the (11-20) plane of the n-type GaN substrate 11 are formed. The inner surface 21b is an example of the “other inner surface of the recess” in the present invention.

Next, a release layer 31 made of In _0.35 Ga _0.65 N having a thickness of about 20 nm is formed on the n-type GaN substrate 11 having the groove 21 by using a metal organic chemical vapor deposition (MOCVD) method, n The light emitting element layer 12 is formed by sequentially laminating the mold cladding layer 13, the light emitting layer 14, the p-type cladding layer 15, and the like. Here, the release layer 31 is made of a material having a smaller band gap than the MQW active layer of the light emitting layer 14. Specifically, in the first embodiment, the release layer 31 is made of InGaN having a higher In composition than the InGaN of the MQW active layer of the light emitting layer 14.

  At this time, in the first embodiment, as shown in FIG. 9, when the light emitting element layer 12 is grown on the n-type GaN substrate 11, the (000-1) plane of the groove 21 extending in the [1-100] direction. In the inner side surface 21a, the light emitting element layer 12 has a crystal growth surface 12a composed of a (000-1) plane extending in the [11-20] direction (C2 direction) so as to take over the (000-1) plane of the groove 21. The crystal grows while forming. Further, on the (0001) plane (inner side surface 21b) side facing the (000-1) plane of the groove portion 21, the light emitting element layer 12 is inclined at a predetermined angle with respect to the [11-20] direction (C2 direction). The crystal grows while forming a crystal growth surface (facet) 12b composed of a (11-22) plane extending in the direction. Thereby, the crystal growth surface 12b is formed so as to form an obtuse angle with respect to the upper surface (main surface) of the light emitting element layer 12.

  In addition, by forming the light emitting element layer 12 by the above-described method, the light emitting element layer 12 stacked on a flat substrate having no groove 21 or the like is etched to correspond to the crystal growth surface 12a or the crystal growth surface 12b. Unlike the case of forming the end faces, the etching process is not required for forming the crystal growth surfaces 12a and 12b, so that the manufacturing process of the LED chip 30 is simplified. Further, since the crystal growth surfaces 12a and 12b are not formed by dry etching or the like, the light emitting layer 14 and the like are hardly damaged in the manufacturing process. Thereby, the light extraction efficiency from the light emitting layer 14 can be improved.

  Further, when the light emitting element layer 12 is crystal-grown on the n-type GaN substrate 11, the inner surface 21a of the groove portion 21 is a starting point rather than the growth rate at which the upper surface of the growth layer (the main surface of the light emitting element layer 12) grows. Since the growth rate of the crystal growth surface 12b starting from the crystal growth surface 12a and the inner surface 21b of the groove portion 21 is low, the upper surface (main surface) of the growth layer grows while maintaining flatness. Thereby, the flatness of the surface (upper surface) of the light emitting element layer 12 having the light emitting layer 14 as compared with the growth layer surface of the light emitting element layer when the end face composed of the crystal growth surface 12a and the crystal growth surface 12b is not formed. Can be further improved.

  Thereafter, as shown in FIG. 6, the crystal growth surface 12 a ((000-1) surface) and the crystal growth surface 12 b ((11-22) surface) of the light emitting element layer 12 are included (including the groove portion 21). An insulating film 22 is formed on the upper surface of the upper portion of the groove portion 21 so as to have a predetermined thickness. And after forming the p side electrode 18 so that the upper surface of the insulating film 22 and the light emitting element layer 12 may be covered, the p side electrode 18 side and the support substrate 32 are joined via the joining layer 33 which consists of AuSn.

Then, similarly to the manufacturing process shown in FIG. 8, laser irradiation is performed from the lower surface side of the n-type GaN substrate 11 toward the release layer 31. At that time, the second harmonic (wavelength: about 532 nm) of the Nd: YAG laser light is adjusted to an energy density of about 500 mJ / cm ² to about 2000 mJ / cm ² , and then from the lower surface side of the n-type GaN substrate 11. Irradiation is intermittently (pulsed) toward the n-type GaN substrate 11. Thereby, the crystal bond of the peeling layer 31 is decomposed and evaporated, and the light emitting element layer 12 side is peeled from the n-type GaN substrate 11. Note that laser light having a wavelength of about 532 nm is absorbed by the release layer 31, but is not absorbed by the substrate (the n-type GaN substrate 11 and the support substrate 32) and the light emitting element layer 12.

  Finally, as shown in FIG. 6, an ITO n-side translucent electrode 16 is formed on the lower surface of the n-type cladding layer 13, and a pad electrode is formed in a predetermined region on the lower surface of the n-side translucent electrode 16. 17 is formed. In this way, the LED chip 30 is formed.

  In the first embodiment, as described above, by providing the light emitting element layer 12 in which the crystal growth surface 12a including the (000-1) plane and the crystal growth surface 12b including the (11-22) surface are formed, Since the crystal growth surfaces 12a and 12b having the plane orientation of FIG. 1 have flatness, the LED light emitted from the light emitting layer 14 inside the light emitting element layer 12 passes through the end surface on which fine irregularities such as etching are formed. In contrast, scattering at the crystal growth surface 12a ((000-1) surface) and the crystal growth surface 12b ((11-22) surface) is suppressed. That is, the light emitted from the light emitting layer 14 is emitted toward the outside of the LED chip 30 in a state where a decrease in the amount of light accompanying scattering or the like is suppressed. As a result, it can suppress that the luminous efficiency of LED chip 30 falls.

  In the first embodiment, the light emitting element layer 12 and the support substrate 32 can be reliably bonded to each other by the bonding layer 33 by bonding the light emitting element layer 12 and the support substrate 32 via the bonding layer 33. .

  In the first embodiment, the crystal growth surface 12 a made of the (000-1) plane and the crystal growth surface 12 b made of the (11-22) surface are constituted by the crystal growth surface of the light emitting element layer 12. Thus, two types of growth surfaces (end surfaces) of the crystal growth surfaces 12 a and 12 b can be formed simultaneously with the crystal growth of the light emitting element layer 12.

  In the first embodiment, the crystal growth surface 12b is configured to have the (11-22) plane, so that the side surface not corresponding to the facet such as the (11-22) plane on the n-type GaN substrate 11 is used. Compared with the surface (main surface) of the growth layer of the light emitting element layer 12 in the case of forming the (end face), the facet (crystal growth surface 12b) composed of the (11-22) plane is formed on the n-type GaN substrate 11. In this case, the surface (upper surface) of the growth layer can be formed so as to ensure flatness. Further, since the crystal growth surface 12b has a slower growth rate than the main surface of the light emitting element layer 12, the crystal growth surface 12b can be easily formed by crystal growth.

  In the first embodiment, the crystal growth surface 12b of the light emitting element layer 12 is inclined with respect to the main surface ((11-20) plane) of the light emitting element layer 12 to form an obtuse angle. Since the region (concave portion 20) where the crystal growth surface 12a and the crystal growth surface 12b of the light emitting element layer 12 face each other is formed so as to spread from the light emitting element layer 12 toward the support substrate 32, In addition to extracting LED light directly from the lower surface side (n-type cladding layer 13 side) of the light emitting element layer 12 in the C1 direction (see FIG. 6), crystal growth inclined with respect to the main surface of the light emitting element layer 12 The light can be reflected from the surface 12b and extracted from the lower surface side of the light emitting element layer 12 in the C1 direction. Thereby, the luminous efficiency of the LED chip 30 can be further improved.

  In the first embodiment, the light emitting element layer 12 is formed by forming the plurality of recesses 20 including the crystal growth surface 12a and the crystal growth surface 12b in the light emitting element layer 12 so that the light emitting element layer 12 is laterally formed by the recesses 20 (FIG. In the manufacturing process, light emission occurs due to stress when the support substrate 32 is bonded to the light emitting element layer 12 and when the n-type GaN substrate 11 is peeled from the light emitting element layer 12 in the manufacturing process. Generation of cracks in the element layer 12 can be suppressed.

  In the first embodiment, the growth substrate is configured to be the n-type GaN substrate 11 made of a nitride-based semiconductor such as GaN, so that light is emitted on the n-type GaN substrate 11 made of the nitride-based semiconductor. Using the crystal growth of the element layer 12, the light emitting element layer 12 having the crystal growth surface 12a composed of the (000-1) plane and the crystal growth surface 12b composed of the (11-22) plane can be easily formed. it can.

(Second Embodiment)
FIG. 10 is a cross-sectional view illustrating a structure of an LED chip according to the second embodiment of the present invention. 11 to 13 are a cross-sectional view and a plan view, respectively, for explaining a manufacturing process of the LED chip according to the second embodiment shown in FIG. With reference to FIGS. 10 to 13, in the manufacturing process of the LED chip 40 according to the second embodiment, unlike the first embodiment, an underlayer 50 made of n-type AlGaN is formed on an n-type GaN substrate 41. The case where the light emitting element layer 42 is formed will be described later. The n-type GaN substrate 41 is an example of the “growth substrate” and the “underlying substrate” in the present invention.

  The LED chip 40 according to the second embodiment is made of a wurtzite structure nitride semiconductor having a (11-2-2) plane as a main surface. Moreover, the shape of the LED chip 40 has a shape such as a square shape, a rectangular shape, a rhombus, or a parallelogram when viewed in a plan view (viewed from the upper surface side of the LED chip 40).

Here, in the manufacturing process of the LED chip 40 in the second embodiment, as shown in FIG. 11, an In _0.35 Ga _{0 ...} Having a thickness of about 20 nm is formed on an n-type GaN substrate 41 having a thickness of about 100 μm _{. A} peeling layer 31 made of ₆₅ N and a base layer 50 made of Ge-doped n-type Al _0.05 Ga _0.95 N having a thickness of about 3 μm to about 4 μm are grown in this order. When the base layer 50 is crystal-grown, since the lattice constant c ₂ of the base layer 50 is smaller than the lattice constant c ₁ of the n-type GaN substrate 41 (c ₁ > c ₂ ), the base layer reaches a predetermined thickness. 50, tension in response to the lattice constant _{c 1} of the n-type GaN substrate 41 in the interior of the base layer 50 stress R (see FIG. 11) is generated. As a result, a crack 51 as shown in FIG. 11 is formed in the underlayer 50 as the underlayer 50 locally shrinks in the A direction. Here, the difference in the c-axis lattice constant between GaN and AlGaN is larger than the difference in the a-axis lattice constant between GaN and AlGaN, so that the crack 51 is formed between the (0001) plane of the foundation layer 50 and n. The GaN substrate 41 is easily formed in the [1-100] direction (B direction) parallel to the (11-2-2) plane of the main surface. Note that FIG. 11 schematically shows a state in which the crack 51 is spontaneously formed in the underlayer 50.

  Further, when the n-type GaN substrate 41 in which the crack 51 is formed is viewed in a plan view, the crack 51 is in a [1-100] direction substantially orthogonal to the A direction of the n-type GaN substrate 41 as shown in FIG. It is formed to extend in a stripe shape along (B direction). The crack 51 is an example of the “concave portion” in the present invention.

Thereafter, as shown in FIG. 13, an n-type cladding layer 43 made of n-type GaN having a thickness of about 0.5 μm is formed on the underlayer 50 by a manufacturing process similar to that of the first embodiment. A light emitting layer made of MQW in which a well layer (not shown) made of Ga _0.7 In _0.3 N having a thickness and a barrier layer (not shown) made of Ga _0.9 In _0.1 N are stacked. The light emitting element layer 42 is formed by sequentially stacking 44 and a p-type cladding layer 45 serving also as a p-type contact layer made of p-type GaN having a thickness of about 0.2 μm. The light emitting element layer 42, the n-type cladding layer 43, the light emitting layer 44, and the p-type cladding layer 45 are examples of the “nitride-based semiconductor layer” in the present invention.

  At this time, in the second embodiment, when the light emitting element layer 42 is grown on the n-type GaN substrate 41, the light emitting element layer 42 is formed on the inner surface 51a of the crack 51 extending in a stripe shape in the [1-100] direction. , While forming a crystal growth surface (facet) 42a composed of a (000-1) plane extending in a direction inclined by a predetermined angle with respect to the [11-2-2] direction (C2 direction) of the n-type GaN substrate 41 grow up. In addition, on the side of the inner surface 51b facing the inner surface 51a of the crack 51, the light emitting element layer 42 is inclined at a predetermined angle with respect to the [11-2-2] direction (C2 direction) of the n-type GaN substrate 41. The crystal grows while forming a crystal growth surface (facet) 42b consisting of a (11-22) plane extending in the direction. The inner side surface 51a and the inner side surface 51b are examples of “one inner side surface of the recess” and “the other inner side surface of the recess” in the present invention, respectively, and the crystal growth surface 42a and the crystal growth surface 42b are respectively These are examples of the “first side surface” and the “second side surface” of the present invention. Thus, the crystal growth surfaces 42a and 42b are formed so as to form obtuse angles with respect to the upper surface (main surface) of the light emitting element layer 42, respectively.

  Note that by forming the light emitting element layer 42 by the above-described method, the light emitting element layer 42 stacked on a flat substrate having no crack 51 or the like is etched to correspond to the crystal growth surface 42a or the crystal growth surface 42b. Unlike the case of forming the end face to be performed, the etching process is not required for forming the crystal growth surfaces 42a and 42b, so that the manufacturing process of the LED chip 40 is simplified. Further, since the crystal growth surfaces 42a and 42b are not formed by dry etching or the like, the light emitting layer 44 and the like are hardly damaged in the manufacturing process. Thereby, the light extraction efficiency from the light emitting layer 14 can be improved.

  Further, when the light emitting element layer 42 is grown on the base layer 50, the crystal starting from the inner side surface 51 a of the crack 51 rather than the growth rate at which the upper surface of the growth layer (the main surface of the light emitting element layer 42) grows. Since the growth rate of the crystal growth surface 42b starting from the growth surface 42a and the inner side surface 51b of the crack 51 is low, the upper surface (main surface) of the growth layer grows while maintaining flatness. Thereby, the flatness of the surface (upper surface) of the light emitting element layer 42 having the light emitting layer 44 as compared with the growth layer surface of the light emitting element layer when the end face composed of the crystal growth surface 42a and the crystal growth surface 42b is not formed. Can be further improved.

  Thereafter, the LED chip 40 according to the second embodiment shown in FIG. 10 is formed by a manufacturing process similar to that of the first embodiment.

  In the second embodiment, as described above, by including the light emitting element layer 42 in which the crystal growth surface 42a including the (000-1) plane and the crystal growth surface 42b including the (11-22) plane are formed, Since the crystal growth surfaces 42a and 42b having the plane orientation are flat, the LED light emitted from the light-emitting layer 44 inside the light-emitting element layer 42 passes through the end surface on which fine irregularities such as etching are formed. In contrast, scattering at the crystal growth surfaces 42a and 42b is suppressed. That is, the light emitted from the light emitting layer 44 is emitted toward the outside of the LED chip 40 in a state where a decrease in the amount of light accompanying scattering or the like is suppressed. As a result, it can suppress that the luminous efficiency of the LED chip 40 falls.

In the second embodiment, the underlying layer 50 made of n-type AlGaN on the n-type GaN substrate 41 is formed, the lattice constant _{c 1} of the n-type GaN substrate 41, the lattice constant _{c 2} of the underlayer 50 _There, c 1> are configured so as to have a relation of _{c 2,} the crystal growth plane 42a and the crystal growth plane 42b of the light emitting element layer 42, respectively, to form the inner surfaces 51a and 51b of the cracks 51 starting respectively Thus, when forming the base layer 50 on the n-type GaN substrate 41, the lattice constant c ₂ of the base layer 50 is smaller than the lattice constant c ₁ of the n-type GaN substrate 41 (c ₁ > c ₂ ). A tensile stress R is generated inside the underlayer 50 in an attempt to match the lattice constant c ₁ on the n-type GaN substrate 41 side. As a result, when the thickness of the underlayer 50 is equal to or greater than a predetermined thickness, the underlayer 50 cannot withstand this tensile stress R, and a crack 51 is formed in the underlayer 50. Thus, the inner side surface serving as a reference for crystal growth of the crystal growth surface 42a ((000-1) surface) and the crystal growth surface 42b ((11-22) surface) of the light emitting element layer 42 on the base layer 50, respectively. 51a and 51b can be easily formed in the foundation layer 50.

  In the second embodiment, the crystal growth surface 42 a ((000-1) plane) and the crystal growth surface 42 b ((11-22) plane) of the light emitting element layer 42 are formed of the crystal growth surface of the light emitting element layer 42. With such a configuration, two types of flat crystal growth surfaces (end surfaces) of the crystal growth surface 42 a and the crystal growth surface 42 b can be easily formed simultaneously with the crystal growth of the light emitting element layer 42.

  In the second embodiment, the crystal growth surfaces 42 a and 42 b of the light emitting element layer 42 are inclined with respect to the main surface ((11-2-2) plane) of the light emitting element layer 42 to form an obtuse angle. By forming in this way, the region (concave portion 20) where the crystal growth surfaces 42a and 42b of the light emitting element layer 42 face each other is formed so as to spread from the light emitting element layer 42 toward the support substrate 32. In addition to taking out LED light from 44 directly from the lower surface side (n-type cladding layer 43 side) of the light emitting element layer 42 in the C1 direction (see FIG. 10), the LED light is inclined with respect to the main surface of the light emitting element layer 42 The light can be reflected from the crystal growth surfaces 42a and 42b and taken out from the lower surface side of the light emitting element layer 42 in the C1 direction. Thereby, the luminous efficiency of the LED chip 40 can be further improved.

  The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

(Third embodiment)
FIG. 14 is a cross-sectional view for explaining the structure of an LED chip according to a third embodiment of the present invention. 15 to 17 are a plan view and a cross-sectional view for explaining a manufacturing process of the LED chip according to the third embodiment shown in FIG. With reference to FIGS. 11 and 14 to 17, in the manufacturing process of the LED chip 60 according to the third embodiment, unlike the second embodiment, a broken line-shaped scribe is formed on the underlayer 50 on the n-type GaN substrate 61. The case where the crack 71 in which the crack generation position is controlled by forming the scratch 70 will be described. The n-type GaN substrate 61 is an example of the “growth substrate” and the “underlying substrate” in the present invention, and the crack 71 is an example of the “concave portion” in the present invention.

  The LED chip 60 according to the third embodiment is made of a wurtzite nitride semiconductor having a (1-10-2) plane as a main surface. Moreover, the shape of the LED chip 60 has a shape such as a square shape, a rectangular shape, a rhombus shape, or a parallelogram shape in a plan view (as viewed from the upper surface side of the LED chip 60).

Here, in the manufacturing process of the LED chip 60 in the third embodiment, In _0.35 Ga having a thickness of about 20 nm on the n-type GaN substrate 61 (see FIG. 17), as in the case shown in FIG. _A peeling layer 31 made of _0.65 N, an n-type contact layer 62 made of Ge-doped n-type GaN having a thickness of about 3 μm, and thinner than the thickness (about 3 μm to about 4 μm) of the second embodiment described above An underlayer 50 made of n-type AlGaN having a thickness of about the critical thickness is grown in this order. At this time, a tensile stress R (see FIG. 17) is generated inside the underlayer 50 by the same action as in the second embodiment. Here, the critical film thickness means the minimum thickness of the semiconductor layer when a semiconductor layer having a different lattice constant is stacked and no cracks are generated in the semiconductor layer due to the difference in lattice constant.

  Thereafter, as shown in FIG. 15, broken line-shaped scribe scratches are formed at intervals of about 50 μm in the [11-20] direction (B direction) substantially perpendicular to the A direction on the underlayer 50 by laser light or diamond points. 70 is formed. A plurality of scribe flaws 70 are formed in the A direction at a pitch of an interval L2 (L2 = about 100 μm). As a result, as shown in FIG. 16, the crack progresses in the region of the underlayer 50 where the scribe flaw 70 is not formed in the underlayer 50, starting from the broken scribe flaw 70. As a result, a substantially linear crack 71 (see FIG. 16) that divides the underlayer 50 in the B direction is formed.

  At that time, the scribe flaw 70 is also divided in the depth direction (C1 direction in FIG. 17). As a result, an inner side surface 71 a (shown by a broken line) reaching the vicinity of the interface between the foundation layer 50 and the n-type contact layer 62 is formed in the crack 71. The inner side surface 71a is an example of “one inner side surface of the recess” in the present invention.

Thereafter, by a manufacturing process similar to that of the second embodiment, an n-type cladding layer 43 and a well layer (not shown) made of Ga _0.7 In _0.3 N having a thickness of about 2 nm are formed on the base layer 50. ) And a light emitting layer 44 made of MQW in which a barrier layer (not shown) made of Ga _0.9 In _0.1 N is laminated, and a p-type cladding layer 45 are sequentially laminated, whereby the light emitting element layer 42. (See FIG. 14).

  At this time, the light emitting element layer 42 on the n-type GaN substrate 61 extends in a direction inclined by a predetermined angle with respect to the [1-10-2] direction (C2 direction) of the n-type GaN substrate 61 (000-1). ) Plane crystal growth surface 42c (see FIG. 14) and the (1-101) plane extending in a direction inclined by a predetermined angle with respect to the [1-10-2] direction (C2 direction) of the n-type GaN substrate 61. A crystal growth surface 42d (see FIG. 14) is formed. The crystal growth surface 42c and the crystal growth surface 42d are examples of the “first side surface” and the “second side surface” of the present invention, respectively.

  The other manufacturing processes according to the third embodiment are the same as those of the second embodiment. In this way, the LED chip 60 according to the third embodiment shown in FIG. 14 is formed.

  In the manufacturing process of the third embodiment, as described above, when the crack 71 is formed, the base layer 50 is formed on the n-type GaN substrate 61 with a thickness of about the critical thickness, and then the base layer 50 is formed. By forming a plurality of broken-line-like (approximately 50 μm spacing) scribe flaws 70 extending in the [11-20] direction (B direction) at a pitch of an interval L2 (= about 100 μm) in the A direction, 50, cracks 71 are formed at equal intervals along the A direction, parallel to the B direction, starting from the broken-line-shaped scribe flaw 70. That is, as in the second embodiment, the LED chip 60 having a uniform light-emitting area can be more easily compared with the case where the semiconductor layers are stacked using the spontaneously formed cracks (see FIG. 14). Can be formed. The remaining effects of the third embodiment are similar to those of the aforementioned second embodiment.

(Fourth embodiment)
FIG. 18 is a cross-sectional view illustrating the structure of an LED chip according to a fourth embodiment of the present invention. 19 to 22 are cross-sectional views for explaining a manufacturing process of the LED chip according to the fourth embodiment shown in FIG. Referring to FIGS. 18 to 22, in the manufacturing process of LED chip 80 according to the fourth embodiment, unlike the first embodiment, a light-emitting element having a main surface composed of an m-plane ((1-100) plane) A case where the layer 12 is formed will be described.

  The LED chip 80 according to the fourth embodiment is made of a nitride semiconductor having a wurtzite structure having an m-plane ((1-100) plane) as a main surface. Moreover, the shape of the LED chip 80 has a shape such as a square shape, a rectangular shape, a rhombus shape, or a parallelogram shape when viewed in plan (viewed from the upper surface side of the LED chip 80).

  As shown in FIG. 18, the LED chip 80 has a light emitting element layer 12 having an n-side electrode 83 formed on the lower surface thereof bonded to a support substrate 82 made of CuW via a bonding layer 33. In addition, an ITO p-side translucent electrode 84 and a pad electrode 17 are formed on the upper surface of the light emitting element layer 12. The remaining structure of the LED chip 80 according to the fourth embodiment is the same as that of the first embodiment.

In the manufacturing process of the LED chip 80 in the fourth embodiment, as shown in FIG. 19, first, n-type GaN having a main surface composed of an m-plane ((1-100) plane) and a thickness of about 100 μm. On the substrate 81, an underlayer 50 made of undoped Al _0.05 Ga _0.95 N having a thickness of about 3 μm to about 4 μm is grown. At that time, as in the second embodiment, a crack 51 is formed in the underlayer 50 due to a difference in lattice constant between the n-type GaN substrate 81 and the underlayer 50. The n-type GaN substrate 81 is an example of the “growth substrate” and the “underlying substrate” in the present invention. Here, the difference in the c-axis lattice constant between GaN and AlGaN is larger than the difference in the a-axis lattice constant between GaN and AlGaN, so that the crack 51 is formed between the (0001) plane of the foundation layer 50 and n. The GaN substrate 81 is easily formed in the [11-20] direction (B direction) parallel to the (1-100) plane of the main surface.

Thereafter, by a manufacturing process similar to that of the first embodiment, a release layer 31 made of In _0.35 Ga _0.65 N having a thickness of about 20 nm and an n-type having a thickness of about 3 μm are formed on the base layer 50. An n-type cladding layer 13 made of Al _0.03 Ga _0.97 N, a well layer (not shown) made of Ga _0.7 In _0.3 N having a thickness of about 2 nm, and Ga _0.9 In _{0 A} light emitting layer 14 having an MQW structure in which a barrier layer (not shown) made of _0.1 N is stacked, and a p-type cladding layer 15 also serving as a p-type contact layer made of p-type GaN having a thickness of about 0.2 μm, Are sequentially laminated to form the light emitting element layer 12 (see FIG. 19).

  At this time, in the fourth embodiment, when the light-emitting element layer 12 is grown on the n-type GaN substrate 81, the inner part made of the (000-1) plane of the crack 51 extending in the [11-20] direction (B direction). In the side surface 51a, the light emitting element layer 12 forms a crystal growth surface 12c composed of a (000-1) plane extending in the [1-100] direction (C2 direction) so as to take over the (000-1) plane of the crack 51. While growing crystal. On the (0001) plane (inner side surface 51b) side facing the (000-1) plane of the crack 51, the light emitting element layer 12 is inclined at a predetermined angle with respect to the [1-100] direction (C2 direction). The crystal grows while forming a crystal growth surface (facet) 12d composed of a (1-101) plane extending in the direction. Thereby, the crystal growth surface 12d is formed so as to form an obtuse angle with respect to the upper surface (main surface) of the light emitting element layer 12. The crystal growth surface 12c and the crystal growth surface 12d are examples of the “first side surface” and the “second side surface” of the present invention, respectively.

In the manufacturing process of the fourth embodiment, as shown in FIG. 19, the crystal growth surface 12c ((000-1) plane) and the crystal growth surface 12d ((1-101) plane) of the light emitting element layer 12 are used. An insulating film 22 such as SiO ₂ that is transparent with respect to the emission wavelength is formed so as to fill the concave portion 20 (a region above the crack 51 including the crack 51) formed in a substantially V shape.

  Thereafter, as shown in FIG. 20, a temporary support substrate 85 is bonded to the p-type cladding layer 15 side of the light emitting element layer 12. As the temporary support substrate 85, for example, a heat release sheet in which a heat release adhesive material is formed on one side of a film such as polyester is used, and the side of the film on which the heat release adhesive material is formed is bonded to the light emitting element layer 12. To do. Thereafter, as shown in FIG. 21, the n-type GaN substrate 81 is peeled off by the same manufacturing process as in the first embodiment. After that, as shown in FIG. 22, on the lower surface of the n-type cladding layer 13, Al having a thickness of about 10 nm, Pt having a thickness of about 20 nm, and W having a thickness of about 300 nm are arranged in order from the n-type cladding layer 13. An n-side electrode 83 made of is formed. Further, the support substrate 82 made of CuW is bonded through the AuSn bonding layer 33. Thereafter, the temporary support substrate 85 is peeled off, and the p-side translucent electrode 84 (see FIG. 18) and the pad electrode 17 (see FIG. 18) are sequentially formed on the p-type cladding layer 15. As the p-side translucent electrode 84, for example, Pd having a thickness of about 5 nm and Au having a thickness of about 5 nm are sequentially stacked from the p-type cladding layer 15 side. In this way, the LED chip 80 shown in FIG. 18 is formed.

  In the fourth embodiment, as described above, by including the light emitting element layer 12 in which the crystal growth surface 12c including the (000-1) plane and the crystal growth surface 12d including the (1-101) plane are formed, Since the crystal growth surfaces 12c and 12d having the plane orientation are flat, the LED light emitted from the light emitting layer 14 inside the light emitting element layer 12 is suppressed from being scattered by the crystal growth surfaces 12c and 12d. That is, the light emitted from the light emitting layer 14 is emitted toward the outside of the LED chip 80 in a state where a decrease in the amount of light accompanying scattering or the like is suppressed. As a result, it can suppress that the luminous efficiency of the LED chip 80 falls.

  In the fourth embodiment, the crystal growth surface 12d of the light emitting element layer 12 is formed so as to be inclined with respect to the main surface ((1-100) plane) of the light emitting element layer 12 so as to form an obtuse angle. Since the region (concave portion 20) where the crystal growth surfaces 12c and 12d of the light emitting element layer 12 face each other is formed so as to narrow from the light emitting element layer 12 toward the support substrate 82, the LED light from the light emitting layer 14 is reduced. Not only in the upper surface side of the light emitting element layer 12 (p-type cladding layer 15 side) but also in the C2 direction (see FIG. 18) through the crystal growth surface 12d inclined with respect to the main surface of the light emitting element layer 12. . Thereby, the luminous efficiency of the LED chip 80 can be further improved.

  The remaining effects of the LED chip 80 according to the fourth embodiment are similar to those of the aforementioned first and second embodiments.

(Fifth embodiment)
FIG. 23 is a cross-sectional view illustrating the structure of an LED chip according to a fifth embodiment of the present invention. FIG. 24 is a cross-sectional view showing a manufacturing process of the LED chip according to the fifth embodiment shown in FIG. 23 and 24, in the manufacturing process of the LED chip 90 according to the fifth embodiment, unlike the first embodiment, the n-type having a main surface composed of an m-plane ((1-100) plane). A case where the light emitting element layer 92 is formed over the 4H—SiC substrate 91 (see FIG. 24) will be described. The n-type 4H—SiC substrate 91 and the light emitting element layer 92 are examples of the “growth substrate” and the “nitride-based semiconductor layer” in the present invention, respectively.

  The LED chip 90 according to the fifth embodiment is made of a nitride semiconductor having a wurtzite structure whose main surface is an m-plane ((1-100) plane). Moreover, the shape of the LED chip 90 has a shape such as a square shape, a rectangular shape, a rhombus, or a parallelogram when viewed in a plan view (when viewed from the upper surface side of the LED chip 90).

Further, as shown in FIG. 23, the LED chip 90 has a light emitting element layer 92 formed thereon. The light emitting element layer 92 includes an n-type cladding layer 93 made of n-type Al _0.03 Ga _0.97 N having a thickness of about 0.5 μm, and Ga _0.7 In _{0. A} light emitting layer 94 having an MQW structure in which a well layer (not shown) made of 3N and a barrier layer (not shown) made of Ga _0.9 In _0.1 N are stacked is formed. A p-type cladding layer 95 also serving as a p-type contact layer made of p-type GaN having a thickness of about 0.2 μm is formed on the light emitting layer 94. The n-type cladding layer 93, the light emitting layer 94, and the p-type cladding layer 95 are examples of the “nitride-based semiconductor layer” in the present invention.

  Here, in the manufacturing process of the LED chip 90 in the fifth embodiment, as shown in FIG. 24, a crystal composed of the (000-1) plane of the light emitting element layer 92 from the n-type cladding layer 93 to the p-type cladding layer 95. The recess 20 is formed by the growth surface 92a and the crystal growth surface 92b composed of the (1-101) plane. The crystal growth surface 92a and the crystal growth surface 92b are examples of the “first side surface” and the “second side surface” of the present invention, respectively. In addition, the crystal growth surface 92 a of the n-type 4H—SiC substrate 91 is inherited from the inner surface 96 a composed of the (000-1) surface of the groove 96 formed in advance on the main surface of the n-type 4H—SiC substrate 91. It is formed to extend in a direction substantially perpendicular to the main surface ([1-100] direction). The crystal growth surface 92b is an inclined surface starting from the inner side surface 96b of the groove portion 96, and is formed so as to form an obtuse angle with respect to the upper surface (main surface) of the light emitting element layer 92. The groove 96 and the inner side surfaces 96a and 96b are examples of the “concave portion”, “one inner side surface of the concave portion”, and “the other inner side surface of the concave portion” of the present invention, respectively. In FIG. 24, the reference numerals of the inner side surface 96a and the inner side surface 96b are shown only in some of the groove portions 96 in the drawing for the purpose of illustration.

As shown in FIG. 23, an n-side translucent electrode 16 made of ITO is formed on the lower surface of the n-type cladding layer 93. A pad electrode 17 made of Au is formed in a partial region on the n-side translucent electrode 16. In addition, an insulating film 22 such as SiO ₂ that is transparent to the emission wavelength is formed so as to fill the recess 20 (see FIG. 24) formed in a substantially V shape. A p-side electrode 18 is formed so as to cover the upper surface of the insulating film 22 and the upper surface of the p-type cladding layer 95. A support substrate 32 made of CuW having a thickness of about 100 μm is bonded onto the p-side electrode 18 via a bonding layer 33 made of AuSn.

  The remaining structure and manufacturing process of the LED chip 90 according to the fifth embodiment are the same as those of the first embodiment. The effects of the fifth embodiment are also the same as those of the first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the LED chip 30 according to the first embodiment, an example in which the light emitting element layer 12 is crystal-grown after forming the groove portion 21 on the main surface composed of the a-plane ((11-20) plane) of the n-type GaN substrate. Although shown, this invention is not restricted to this, For example, the state which formed the groove part (recessed part) in the main surface perpendicular | vertical to the (000 +/- 1) surface of n-type GaN substrates, such as m surface ((1-100) surface) The light emitting element layer may be crystal-grown.

  In the LED chip 80 according to the fourth embodiment, an example in which the crack 51 is spontaneously formed in the underlayer 50 using the lattice constant difference between the n-type GaN substrate 81 and the underlayer 50 is used. Although the present invention is not limited to this, as in the third embodiment, a crack in which the generation position of a crack is controlled by forming a broken-line-shaped scribe flaw on the underlayer on the n-type GaN substrate is shown. You may make it form.

  In the LED chips according to the second to fourth embodiments, an n-type GaN substrate is used as a base substrate, and a base layer made of AlGaN is formed on the n-type GaN substrate. In addition to using an InGaN substrate as a base substrate, a base layer made of GaN or AlGaN may be formed on the InGaN substrate.

  In the LED chip according to the second and fourth embodiments, an example in which a crack is spontaneously formed in the underlayer due to a difference in lattice constant between the n-type GaN substrate and the underlayer has been described. The invention is not limited to this, and scribe scratches are formed only at both ends in the B direction (see FIG. 12) of the base layer 50 (see FIG. 12) (regions corresponding to the ends in the B direction of the n-type GaN substrate 41). May be. Even if comprised in this way, the crack extended in a B direction can be introduce | transduced easily from the scribe flaw of both ends.

  Moreover, in the LED chip according to the third embodiment, the example in which the scribe scratches 70 for introducing cracks are formed in a broken line shape (at intervals of about 50 μm) in the base layer 50 is shown, but the present invention is not limited thereto, and the base layer is not limited thereto. Scribe flaws may be formed on both end portions of 50 in the B direction (see FIG. 15) (regions corresponding to the end portions of the n-type GaN substrate 61). Even if comprised in this way, the crack extended in a B direction can be introduce | transduced easily from the scribe flaw of both ends.

  In the LED chips according to the third to fifth embodiments, the example in which the insulating film 22 is embedded in the substantially V-shaped recess 20 has been described. However, the present invention is not limited to this, and the first and second embodiments described above. Similarly to the embodiment, an insulating film may be formed in a substantially V shape so as to cover the first side surface or the second side surface of the light emitting element layer, and an electrode that also serves as a reflective film may be formed on the insulating film.

It is sectional drawing for demonstrating the schematic structure of the LED chip by this invention. It is the figure which showed the range of the normal direction of the main surface of the growth board | substrate in the case of forming a semiconductor light-emitting device using the crystal orientation of a nitride-type semiconductor, and the manufacturing process in this invention. It is sectional drawing for demonstrating the schematic manufacturing process of the LED chip by this invention. It is sectional drawing for demonstrating the schematic manufacturing process of the LED chip by this invention. It is sectional drawing for demonstrating the schematic manufacturing process of the LED chip by this invention. 1 is a cross-sectional view illustrating a structure of an LED chip according to a first embodiment of the present invention. FIG. 7 is a plan view for explaining a manufacturing process of the LED chip according to the first embodiment shown in FIG. 6. FIG. 7 is a cross-sectional view for explaining a manufacturing process of the LED chip according to the first embodiment shown in FIG. 6. FIG. 7 is a cross-sectional view for explaining a manufacturing process of the LED chip according to the first embodiment shown in FIG. 6. It is sectional drawing which showed the structure of the LED chip by 2nd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the LED chip by 2nd Embodiment shown in FIG. It is a top view for demonstrating the manufacturing process of the LED chip by 2nd Embodiment shown in FIG. It is sectional drawing for demonstrating the manufacturing process of the LED chip by 2nd Embodiment shown in FIG. It is sectional drawing for demonstrating the structure of the LED chip by 3rd Embodiment of this invention. It is a top view for demonstrating the manufacturing process of the LED chip by 3rd Embodiment shown in FIG. It is a top view for demonstrating the manufacturing process of the LED chip by 3rd Embodiment shown in FIG. It is sectional drawing for demonstrating the manufacturing process of the LED chip by 3rd Embodiment shown in FIG. It is sectional drawing which showed the structure of the LED chip by 4th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the LED chip by 4th Embodiment shown in FIG. It is sectional drawing for demonstrating the manufacturing process of the LED chip by 4th Embodiment shown in FIG. It is sectional drawing for demonstrating the manufacturing process of the LED chip by 4th Embodiment shown in FIG. It is sectional drawing for demonstrating the manufacturing process of the LED chip by 4th Embodiment shown in FIG. FIG. 6 is a cross-sectional view illustrating a structure of an LED chip according to a fifth embodiment of the present invention. It is sectional drawing for demonstrating the manufacturing process of the LED chip by 5th Embodiment shown in FIG.

Explanation of symbols

1 First semiconductor (growth substrate, nitride semiconductor layer)
2 Light emitting layer (nitride semiconductor layer)
3 Second semiconductor (nitride semiconductor layer)
7 Growth substrate 11 n-type GaN substrate (growth substrate)
12, 42, 92 Light emitting element layer (nitride semiconductor layer)
12a, 12c, 42a, 42c, 92a Crystal growth surface (first side surface)
12b, 12d, 42b, 42d, 92b Crystal growth surface (second side surface)
13, 43, 93 n-type cladding layer (nitride-based semiconductor layer)
14, 44, 94 Light emitting layer (nitride semiconductor layer)
15, 45, 95 p-type cladding layer (nitride-based semiconductor layer)
21, 96 Groove (recess)
21a, 51a, 71a, 96a Inner surface (one inner surface of the recess)
21b, 51b, 71b, 96b Inner surface (the other inner surface of the recess)
41, 61, 81 n-type GaN substrate (growth substrate, base substrate)
33 Bonding layer 50 Underlayer 51, 71 Crack (recess)
91 n-type 4H-SiC substrate (growth substrate)

Claims (6)

A nitride-based semiconductor layer including a first side composed of a (000-1) plane and a second side in a region facing the first side;
A support substrate bonded to the nitride-based semiconductor layer ,
At least one of the first side surface and the second side surface is a nitride semiconductor light emitting diode formed so as to be inclined with respect to a main surface of the nitride semiconductor layer .   The nitride-based semiconductor light-emitting diode according to claim 1, wherein the nitride-based semiconductor layer and the support substrate are bonded via a bonding layer.   The nitride-based semiconductor light-emitting diode according to claim 1, wherein the first side surface and the second side surface are formed of a crystal growth surface of the nitride-based semiconductor layer.   The second side surface is composed of {A + B, A, −2A−B, 2A + B} planes (where A ≧ 0 and B ≧ 0, and at least one of A and B is not 0). The nitride semiconductor light emitting diode according to any one of claims 1 to 3. Forming a recess in the main surface of the growth substrate;
On the main surface of the growth substrate, there is a light emitting layer, the first side surface comprising a (000-1) plane starting from one inner side surface of the concave portion, and the concave portion in a region facing the first side surface. A step of growing a nitride-based semiconductor layer including a second side surface starting from the other inner side surface of
Bonding a support substrate to the nitride-based semiconductor layer;
Removing the growth substrate ,
The growth substrate includes a base substrate and a base layer formed on the base substrate and made of AlGaN,
When the lattice constants of the base substrate and the base layer are c ₁ and c ₂ , respectively, the relationship is c ₁ > c ₂ ,
Each of the first side surface and the second side surface is formed starting from an inner side surface of a crack formed so as to extend substantially parallel to the (0001) plane of the base layer and the main surface of the base substrate. A method for manufacturing a nitride semiconductor light emitting diode. 6. The method for manufacturing a nitride semiconductor light emitting diode according to claim 5 , wherein the growth substrate is made of a nitride semiconductor.

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