JP2007019263A - Semiconductor light-emitting device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting device capable of improving light extraction efficiency. <P>SOLUTION: There are provided: an active layer 24 where there are irregularities on a first main surface, and a second main surface opposite to the first one; an n-type cladding layer 25 that is connected to the side of the first main surface where a surface far from the first main surface forms an irregular surface having the same cycle of irregularities as those of the irregular surfaces; a p-type adhesive layer 22 that is connected to the side of the second main surface where a surface far from the second main surface becomes a plane surface substantially; a luminous layer configuration section 20 that can emit light at a specified wavelength; an n-side electrode 41 formed on a surface opposite to the active layer 24 in the n-type cladding layer 25; a p-type GaP substrate 10 that is joined to the adhesive layer 22 at the luminous layer configuration section 20, and substantially transparent to a luminous wavelength; and a p-side electrode 43 formed on a surface opposite to the adhesive layer 22 of the p-type GaP substrate 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor light emitting device aiming at improving light extraction efficiency and a method for manufacturing the semiconductor light emitting device.

In recent years, semiconductor light-emitting elements in the visible region using InGaAlP-based materials for display and the like have been widely applied. In this InGaAlP-based material, for example, the composition of the active layer to be epitaxially grown is In _0.5 (Ga _{1 -X} Al _X ) _0.5 P, and the composition of the n-type / p-type cladding layer is In _0.5 (Ga ₁₋ when the _Y Al _{Y) 0.5} P, by selecting the X or Y appropriately, emitting green band from the red band can be obtained.

  In order to use it for display or the like, it is required to make the semiconductor light emitting element brighter, and proposals for realizing it have been made. In order to obtain a brighter semiconductor light emitting device, it is necessary to take measures to efficiently extract emitted light out of the semiconductor light emitting device.

  When light is incident on an interface having a difference in refractive index at an angle greater than the critical angle, the light is totally reflected at the interface and is not extracted to the opposite side of the interface. If the outer surface surrounding the semiconductor light emitting element is formed as a flat surface, a part of the light emitted in the semiconductor light emitting element is not extracted from the outer surface to the outside, and the light extraction efficiency is lowered.

  As a method for solving this, the surface of the n-type GaAs substrate is made uneven (mountains and valleys), and the light-emitting portion arranged on the substrate, that is, the n-type cladding layer, the active layer, and the p-type cladding layer are formed. There is disclosed a semiconductor light emitting device having a structure in which crystals are sequentially grown on the surface of a GaAs substrate, and the surface shape of each semiconductor layer constituting the light emitting portion is an uneven shape corresponding to the uneven shape of the GaAs substrate (for example, , See Patent Document 1).

In this disclosed method, there is a possibility that a semiconductor light emitting device having a relatively high light extraction efficiency due to an increase in light emission area due to the active layer having an uneven shape and a relatively high light extraction efficiency due to the surface having an uneven shape may be obtained. Since the substrate absorbs a lot of visible light, there is a problem in that the light emitted from the light emitting portion (light emitting layer constituting portion) and passing through the GaAs substrate is absorbed, and the ratio of the light extracted from the semiconductor light emitting element is reduced.
Japanese Laid-Open Patent Publication No. 8-222276 (page 3, FIG. 1)

  The present invention provides a semiconductor light emitting device capable of improving the light extraction efficiency and a method for manufacturing the same.

  The semiconductor light-emitting element of one embodiment of the present invention is connected to a first main surface and an active layer having an uneven surface on the second main surface opposite to the first main surface, the first main surface being connected to the first main surface. The first conductivity type first growth layer in which the surface far from the first main surface forms an uneven surface having the same period as the uneven surface, and the second main surface side are connected to the second main surface side. A second growth layer of a second conductivity type in which a surface far from the main surface of the first surface is substantially planar, and a light emitting layer constituting part capable of emitting light at a specific wavelength; and an active layer of the first growth layer A first conductive side electrode formed on the opposing surface; a second conductive type semiconductor substrate that is bonded to the second growth layer of the light emitting layer constituting portion and is substantially transparent to the wavelength; and the semiconductor substrate And a second conductive side electrode formed on a surface facing the second growth layer.

  According to another aspect of the present invention, there is provided a method for manufacturing a semiconductor light emitting device, wherein the first semiconductor substrate on which the first conductive type uneven surface is formed has the uneven surface capable of emitting light at a predetermined wavelength. Forming a light emitting layer constituting portion in which a first conductivity type cladding layer, an active layer, a second conductivity type cladding layer, and the second conductivity type adhesive layer are sequentially provided; and The step of flattening the uneven surface by heat treatment, and bonding the bonded surface to the surface of the flattened adhesive layer by bonding a transparent substrate to the wavelength of the second conductivity type and performing heat treatment And the first semiconductor substrate, the light emitting layer constituent part, and the second conductive type substrate which are integrated by bonding, leaving the second conductive type substrate to the light emitting layer constituent part. And a step of removing others.

  ADVANTAGE OF THE INVENTION According to this invention, the semiconductor light-emitting device which can improve light extraction efficiency, and its manufacturing method can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In the figure shown below, the same code | symbol is attached | subjected to the same component and the important component is expanded and displayed compared with the other component.

  A semiconductor light emitting device according to Example 1 of the present invention will be described with reference to FIGS. FIG. 1 schematically shows the structure of a semiconductor light emitting device. FIG. 1A is a plan view, FIG. 1B is a cross-sectional view taken along line AA in FIG. FIG. 3C is a perspective view schematically showing the uneven shape of the surface portion of the broken-line circle B in FIG. FIG. 2 is a cross-sectional view of a layer structure schematically showing a method for manufacturing a semiconductor light emitting device in the order of steps. FIG. 3 is a cross-sectional view schematically showing the method of manufacturing the semiconductor light emitting device in the order of steps following the step shown in FIG. FIG. 4 is a cross-sectional view schematically showing the structure of a semiconductor light emitting device on which a semiconductor light emitting element is mounted.

  First, as shown in FIG. 1, the main part of the semiconductor light emitting element 1 is a p-type GaP substrate 10 which is a second conductivity type semiconductor substrate, and a light emitting layer constituting part disposed on the upper surface side of the p-type GaP substrate 10. 20, an n-side electrode 41 that is a circular first conductive side electrode at the center of the upper surface of the light emitting layer constituting unit 20, and a p-side electrode 43 that is a second conductive side electrode on the bottom surface of the p-type GaP substrate 10 Is formed. The light emitting layer constituting unit 20 includes, in order from the p-type GaP substrate 10 side, a p-type adhesion layer 22, a p-type cladding layer 23, an active layer 24, and a first conductivity type first growth, which are second growth layers. An n-type clad layer 25 as a layer is laminated, and a boundary surface and an upper surface of each layer form a serrated uneven surface 13 having cross sections having unevenness with the same period. The upper surface of the n-side electrode 41 is a surface having irregularities with the same period as the irregular surface 13. On the other hand, the boundary surface between the light emitting layer constituting unit 20 and the p-type GaP substrate 10, the boundary surface between the p-type GaP substrate 10 and the p-side electrode 43, and the bottom surface of the p-side electrode 43 form a flat surface.

  Furthermore, as shown in FIG. 1A, the upper surface of the semiconductor light emitting device 1 is substantially square with one side of the outer shape being about 300 μm, and a crest 14 formed on the upper surface of the n-type cladding layer 25 (solid line). And the trough part 15 (broken line) is the uneven | corrugated surface 13 in which the plurality was parallelly arranged mutually in the up-down direction of the top view. A circular n-side electrode 41 made of, for example, AuGe / Au and having a diameter of 120 μm is formed at the center of the upper surface of the light-emitting layer constituting unit 20, and the surface of the n-side electrode 41 is formed on the lower light-emitting layer constituting unit 20. In this structure, the intervals (cycles) between the crests 14 and the troughs 15 of the uneven surface 13 are copied almost the same.

  As shown in FIG. 1B, the cross section along the line AA is a rectangular shape having a visual distance of approximately 250 μm from the upper surface of the light emitting layer constituting unit 20 to the p-side electrode 43. Accordingly, the side surface has a rectangular outer shape of approximately 250 μm × 300 μm. The peaks 14 and valleys 15 seen on the upper surface side of the light emitting layer constituting portion 20 are copied to the upper surface side of the adhesive layer 22 with almost the same period and height difference. The p-type GaP substrate 10 and the adhesive layer 22 are bonded and integrated with a bonding surface 35 that is almost a plane as a boundary. A state in which mechanical strength is ensured and electrical resistance is reduced is referred to as bonding. On the bottom surface side of the p-type GaP substrate 10, for example, a p-side electrode 43 made of AuZn / Au is formed on the entire surface.

  The two crests 14 surrounded by the broken-line circle B shown in FIG. 1A and the valley 15 between the crests 14 have a shape as shown in FIG. 1C, for example. An angle 45 formed by a plane formed by connecting the valleys 15 and a slope from the valleys 15 toward the peaks 14 is, for example, about 35 degrees. When the area of the active layer 24 is increased, and a part of the constituent layer interface of the light emitting layer constituting unit 20 is made to function as a reflective layer to perform etching processing and epitaxial growth, the angle 45 is about 30 to 60 degrees. preferable. The height difference 46 between the peak portion 14 and the valley portion 15 is, for example, about 1.8 μm. The height difference 46 is preferably about 0.3 μm to 5 μm in order to ensure the uneven shape during growth or heat treatment and avoid the InGaP adhesive layer 22 from becoming thick.

  Next, the details of the components of the semiconductor light emitting device 1 will be described according to the manufacturing process of the semiconductor light emitting device 1 with reference to FIGS. In addition, although the manufacturing process of the semiconductor light-emitting device 1 proceeds in units of wafers and is finally separated into individual pieces, FIGS. 2 and 3 show a portion corresponding to one to be separated into individual pieces.

  As shown in FIG. 2A, an Si-doped n-type GaAs substrate 29 having a diameter of 3 inches (about 76 mm) is prepared, and a patterned resist 31 is formed on the surface thereof by a known photolithography method. . The n-type GaAs substrate 29 is selected because it can be lattice-matched with the InGaAlP-based light emitting layer constituting unit 20. The resists 31 are formed in stripes at regular intervals at positions where the peaks on the n-type GaAs substrate 29 are to be formed. For example, the resist 31 has a width of about 1 μm or less and a distance of about 5 μm. The n-type GaAs substrate 29 on which the resist 31 is formed is anisotropically etched with, for example, an etching solution in which sulfuric acid, hydrogen peroxide, and water are mixed. A striped uneven surface 33a having a peak portion along the resist 31 and a valley portion in the middle of the resists 31 adjacent to each other can be formed.

  As shown in FIG. 2 (b), the n-type GaAs substrate 29 after the etching and resist 31 stripping and the like is finished has an interval between crests of about 5 μm and an etching depth, that is, a difference in height between crests and troughs. It has an uneven surface 33a of 1.8 μm. Note that when the width of the resist 31 is increased, a portion of the n-type GaAs substrate 29 that is in contact with the resist 31 remains in the peak portion, but the area may be smaller than the slope connecting the peak portion and the valley portion.

  As shown in FIG. 2C, the epitaxial growth layer is formed using, for example, a well-known MOCVD (Metalorganic Chemical Vapor Deposition) apparatus. An approximately 0.5 μm-thick buffer layer 27 made of n-type GaAs, an approximately 0.05 μm-thick etching stop layer 26 made of n-type InAlP on the uneven surface 33a of the n-type GaAs substrate 29, and an n-type on the surface thereof. An n-type cladding layer 25 made of InAlP having a thickness of about 0.6 μm, an active layer 24 made of InGaAlP having a thickness of about 0.4 μm on the surface, and a p-type cladding layer 23 made of p-type InAlP on the surface having a thickness of about 0.6 μm. An adhesive layer 22a made of p-type InGaP and having a thickness of about 1.1 μm is epitaxially grown on the surface.

  Of these epitaxial growth layers, the active layer may have an MQW structure as required. Further, for example, the n-type or p-type cladding layers 25 and 23 can be replaced with ternary layers. Further, a current diffusion layer may be formed on the side of the n-type or p-type clad layer 25, 23 far from the active layer 24, or a contact layer or the like for reducing the resistance is formed when contacting the electrode metal. May be. Here, the adhesive layer 22 (or 22a) and the epitaxial layer from the p-type cladding layer 23 to the n-type cladding layer 25 involved in light emission are referred to as a light-emitting layer constituting unit 20.

  As shown in FIG. 2D, the adhesive layer 22 exposed on the surface is made of, for example, a gas containing phosphine (PH3) and a dopant (for example, Zn) in a state of being placed in an MOCVD apparatus. By performing heat treatment while supplying, the constituent elements of the crests of the concavo-convex surface 33b or a part thereof move so as to fill the troughs, and crystal growth (referred to as a mass transport method) is performed. . The adhesive layer 22 has a thickness of about 2 μm at the thickest portion. Here, a cover layer made of InAlP and having a thickness of about 0.15 μm may be epitaxially grown on the surface of the flattened adhesive layer 22.

  Next, as shown in FIG. 3 (a), the adhesive layer 22 is placed facing upward, and placed thereon so that the surface to be bonded of the p-type GaP substrate 10 faces downward. The GaP substrate 10 is bonded at room temperature. This bonded surface becomes a bonding surface 35 described later. GaAs has a large absorption of emitted visible light. On the other hand, GaP is selected as a support substrate because it has much lower absorption and is substantially transparent to the emitted visible light. In bonding, lattice matching as much as in epitaxial growth is not always necessary.

  The p-type GaP substrate 10 has the same crystal orientation as that of the n-type GaAs substrate 29. For example, the p-type GaP substrate 10 has a diameter of 3 inches and a thickness of 250 μm, and is doped with Zn at a concentration of about 3E17 / cm 3. Thereafter, the adhesion between the adhesive layer 22 and the p-type GaP substrate 10 is performed by, for example, finally performing a heat treatment in a temperature range of 600 ° C. to 900 ° C. in an argon atmosphere containing 10% hydrogen to react the adhesion interface. As a result, the mechanical strength is ensured and the electrical resistance is reduced. In addition, before bonding the adhesive layer 22 and the p-type GaP substrate 10 at room temperature, a mass transport method is performed by performing a heat treatment in a state where the two are close to each other. Planarization may be performed. Further, in place of the mass transport method performed in the MOCVD apparatus shown in FIG. 2D, by performing a heat treatment in a state where the adhesive layer 22a and the p-type GaP substrate 10 are brought close to each other, the adhesive layer 22a Even if it flattens, it does not interfere.

  Next, the n-type GaAs substrate 29 and the buffer layer 27 on the n-type GaAs substrate 29 side bonded and integrated with the p-type GaP substrate 10 are removed by etching with a mixed solution of ammonia and hydrogen peroxide, and then etched. The stop layer 26 is removed by etching with phosphoric acid at 70 ° C., for example, and the n-type cladding layer 25 is exposed on the surface. As shown in FIG. 3B, the light emitting layer constituting unit 20 is joined to the p-type GaP substrate 10. The n-type GaAs substrate 29 may be removed by etching after being thinned by grinding or polishing.

  As shown in FIG. 3 (c), the p-type GaP substrate 10 formed in FIG. 3 (b) and the light-emitting layer constituting part 20 bonded to the surface thereof are rotated 180 degrees to reverse the top and bottom, and p The type GaP substrate 10 is placed below. The p-type GaP substrate 10 may have its entire surface or a part of its thickness adjusted as necessary. Note that the crests 14 and troughs 15 constituting the uneven surface 13 correspond to the troughs and crests of the n-type GaAs substrate 29, respectively.

  Next, as shown in FIG. 3D, an electrode is formed on the light emitting layer constituting section 20 having the p-type GaP substrate 10 and the n-type cladding layer 25 as surface layers. First, AuZn / Au is deposited on the surface of the p-type GaP substrate 10 and heat treatment is performed to form the p-side electrode 43. Next, patterning is performed on the light emitting layer constituting unit 20, AuGe / Au is deposited, heat treatment is performed, and the n-side electrode 41 is formed. The n-side electrode 41 is, for example, a circle having a diameter of 120 μm, and the p-side electrode 43 is a full surface electrode. In addition, the wafer which has advanced the manufacturing process is separated into pieces by, for example, dicing (not shown), and becomes the semiconductor light emitting element shown in FIG. 3D, that is, the semiconductor light emitting element 1 shown in FIG.

  As shown in FIG. 4, the semiconductor light emitting element 1 formed through the above-described steps is mounted on a header 61 and assembled to the semiconductor light emitting device 80, for example. The p-side electrode 43 on the bottom surface of the semiconductor light emitting element 1 is mounted on the bottom of the cup 63 having a concave shape of the header 61 via a conductive adhesive 68 such as Ag paste. The n-side electrode 41 of the semiconductor light emitting element 1 is connected to one end portion of the lead 66 by, for example, an Au wire 69. The slope of the cup part 63 forms a reflecting surface whose opening diameter increases toward the direction of extracting light. A lead 65 is connected to the header 61. The semiconductor light emitting device 1, the Au wire 69, the header 61, a part of the leads 65 and 66, and the like are sealed in a bullet shape with a sealing resin 71 made of, for example, an epoxy resin to form the semiconductor light emitting device 80.

  When the semiconductor light-emitting element 1 that has become the semiconductor light-emitting device 80 is energized from the p-side electrode 41 and the n-side electrode 31 via the leads 65 and 66, the current is emitted from the light-emitting layer constituting unit 20, The part is taken out directly from the upper surface on the n-side electrode 41 side to the sealing resin 71 side, and is emitted in the top direction of the dome-shaped sealing resin 71. Part of the light reaching the transparent p-type GaP substrate 10 side is extracted from the side surface to the sealing resin 71 side, reflected by the reflecting surface of the cup portion 63, and much in the top direction of the dome-shaped sealing resin 71 Emitted. Note that light incident on the upper surface or the side surface of the semiconductor light emitting device 1 at a critical angle (approximately 27 degrees when the refractive index of the sealing resin 71 is 1.5) or more is reflected by these surfaces and is less than the critical angle. From this surface, it is taken out to the sealing resin 71 side.

  The semiconductor light emitting device 1 of the present embodiment has a feature that an uneven surface is formed in a portion related to light emission of the light emitting layer constituting portion 20, and a portion related to adhesion is flattened, and the absorption of emitted light is large. The GaAs substrate is replaced with a p-type GaP substrate 10 that is substantially transparent to light. Immediately before the emitted light is incident on the p-type GaP substrate 10, an InGaP adhesive layer 22 having a maximum thickness of about 2 μm is disposed. However, since the adhesive layer 22 is formed much thinner than a conventional GaAs substrate having a thickness of about 250 μm, light directed toward the p-type GaP substrate 10 out of the light emitted from the light emitting layer constituting unit 20 Although most of it is absorbed by the adhesive layer 22, most of it passes through the p-type GaP substrate 10 and is taken out of the semiconductor light emitting device 1 from the side surface of the p-type GaP substrate 10. As a result, it is possible to obtain a semiconductor light emitting device 80 that is about 30% brighter under the same current injection conditions as compared with a semiconductor light emitting element having a rugged surface on the upper surface using a GaAs substrate.

  In addition, the uneven surface formed on the upper surface of the light emitting layer constituting unit 20 can increase the ratio of light incident at a critical angle or less, and at the interface with the n-side electrode, the direction is greatly changed to the side surface direction. Can be reflected. The active layer of the light emitting layer constituting unit 20 can increase the area contributing to light emission due to the uneven shape. Moreover, a part of the boundary surface of the unevenness inside the light emitting layer constituting part 20 can reflect light, and the ratio of the light incident on the upper surface and the side surface of the semiconductor light emitting element 1 at a critical angle or less. Can be increased. As a result, it is possible to extract more light out of the semiconductor light emitting element 1 as compared with the case where the interface and upper surface of the light emitting layer constituting unit 20 are flat.

  That is, according to the present embodiment, it is possible to provide a semiconductor light emitting device capable of improving the light extraction efficiency and a manufacturing method thereof.

  Furthermore, the interface between the upper surface of the light emitting layer constituting portion 20 and the n-side electrode is an uneven surface, the contact area is increased, the contact resistance is reduced, and more current can be injected. The brighter semiconductor light emitting device 1 can be obtained by increasing the area contributing to light emission due to the uneven shape of the active layer and increasing the injection current.

  A semiconductor light emitting device according to Example 2 of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view schematically showing a method for manufacturing a semiconductor light emitting device. FIG. 5 schematically shows the structure of the semiconductor light emitting device. FIG. 5A is a plan view, FIG. 5B is a cross-sectional view taken along the line CC in FIG. FIG. 5C is a perspective view schematically showing the concavo-convex shape of the surface portion of the broken-line circle D in FIG. 5A, and FIG. 5D is a relationship in which the concavo-convex shape in FIG. 5C is inverted. It is a perspective view which shows an uneven | corrugated shape typically. The difference from Example 1 is that the uneven surface has a shape having a quadrangular pyramid. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different components will be described.

  First, as shown in FIG. 5, the main part of the semiconductor light emitting element 2, that is, the stacked structure and the electrode structure with crystal growth are the same as those of the semiconductor light emitting element 1. The boundary surface and the upper surface of the adhesive layer 22, the p-type cladding layer 23, the active layer 24, and the n-type cladding layer 25 constituting the laminated light emitting layer constituting portion 20 form an uneven surface 53 formed by the sides of a quadrangular pyramid. ing.

  Further, as shown in FIG. 5A, the upper surface of the semiconductor light emitting device 2 intersects the valley 15 (broken line) that becomes the bottom surface of the quadrangular pyramid formed on the upper surface of the n-type cladding layer 25 and the side surfaces of the quadrangular pyramid. This is a structure having a ridge (solid line) and a vertex of a quadrangular pyramid at a position where the ridge and the ridge intersect. The surface of the n-side electrode 41 formed at the center of the upper surface of the light emitting layer constituting part 20 is such that the side surfaces of the four-sided pyramids of the uneven surface 53 of the lower light emitting layer constituting part 20 are copied at almost the same interval (period). Structure.

  As shown in FIG. 5B, the cross section along the line CC is the same as that of the semiconductor light emitting device 1. The peaks 54 and valleys 55 seen on the upper surface side of the light emitting layer constituting portion 20 are copied to the upper surface side of the adhesive layer 22 with almost the same pitch and height difference.

  The five quadrangular pyramid portions surrounded by the broken-line circle D shown in FIG. 5A have a shape as shown in FIG. 5C, for example. An angle formed between a plane formed by connecting the valley portions 55 and a slope extending from the valley portions 55 to the mountain portions 54 is, for example, about 35 degrees. The height difference between the peak portion 54 and the valley portion 55 is, for example, about 1.8 μm. The height difference is preferably about 5 μm at maximum in order to avoid the adhesive layer 22 made of InGaP from becoming thick.

  The manufacturing process of the semiconductor light emitting element 2 is different from the manufacturing process of the semiconductor light emitting element 1 on the n-type GaAs substrate 29, as shown in FIG. The resist patterning for forming the opening (called the quadrangular pyramid opening 57) arranged in the deep part and the layer thickness of the epitaxial growth of the adhesive layer are different, but the others are almost the same. The sectional view of the manufacturing process is almost the same as that of the first embodiment and will be described with reference to FIG.

  That is, as shown in FIG. 2A, the resist 31 is formed in a stripe shape intersecting with a cross at a position where the base of the quadrangular pyramid opening 57 on the n-type GaAs substrate 29 is to be formed. For example, the resist 31 has a width of about 1 μm or less and a distance in each direction of about 5 μm. The n-type GaAs substrate 29 on which the resist 31 is formed is etched as in the first embodiment. A quadrangular pyramid as shown in FIG. 5 (d), with the peak portion along the resist 31 as the base and the apex at the point where the center of the square formed by the adjacent resists 31 is dug in the direction of the n-type GaAs substrate 29. An opening 57 is formed, and an uneven surface can be formed. When the width of the resist 31 is increased, a portion of the n-type GaAs substrate 29 that is in contact with the resist 31 remains at the apex, but the area may be smaller than that of the inclined surface forming the quadrangular pyramid opening 57.

  The etching shape may be changed depending on the pattern shape of the resist 31. For example, it is possible to obtain a conical opening from a circular opening pattern and a polygonal pyramid opening having a polygonal bottom surface from a polygonal opening pattern. Depending on the orientation of the crystal plane to be etched, the type of etching solution or etching gas, the processing conditions, etc., it is possible to obtain a frustum-shaped opening or a polygonal frustum-shaped opening.

  Next, as shown in FIG. 2C, an epitaxial growth layer is formed. The adhesive layer 22a made of p-type InGaP has a thickness of about 0.8 μm, which is thinner than that of the first embodiment. Compared to the first embodiment, since the etched portion is small, the p-type InGaP used for moving and filling by the mass transport method is small.

  As shown in FIG. 5, it goes without saying that the peaks 54 and valleys 55 constituting the uneven surface 53 correspond to the valleys and peaks of the n-type GaAs substrate 29, respectively. A four-sided pyramid that is epitaxially grown is left in the opening 57, and the uneven surface 53 is formed.

  Hereinafter, through the same manufacturing process as in Example 1, the semiconductor light emitting device 2 in which the uneven surface 53 of the surface of the light emitting layer constituting part 20 and the unevenness of the surface of the n-side electrode 41 are different from those of the semiconductor light emitting device 1 of Example 1. Can be produced. The semiconductor light emitting device 2 of this example is assembled in the same manner as in Example 1, and the same effect as that of the semiconductor light emitting device 80 obtained in Example 1 can be obtained under the same current injection conditions as in Example 1. Furthermore, a semiconductor light-emitting device that is about 5% brighter than the semiconductor light-emitting device 80 of Example 1 can be obtained. This is because the uneven surface 53 formed on the upper surface of the light emitting layer constituting part 20 of the semiconductor light emitting device 2 forms a surface having four different directions, so that the semiconductor light emitting device 1 of Example 1 has a different surface. Compared with a plane in two directions, it can be reflected in more various directions, and as a result, it is possible to increase the proportion of light extracted outside the semiconductor light emitting element 2 by being incident at a critical angle or less. Because.

  As a modification of the second embodiment, it is possible to form a semiconductor light emitting element having a concavo-convex surface formed with a quadrangular pyramid opening 57 as shown in FIG.

  In Example 2, an uneven surface having a quadrangular pyramidal opening 57 as shown in FIG. 5D is formed on the n-type GaAs substrate 29, and the surface of the light emitting layer constituting portion 20 of the semiconductor light emitting element 2 is An uneven surface 53 having a quadrangular pyramid as shown in FIG. On the contrary, an uneven surface having a quadrangular pyramid as shown in FIG. 5C is formed on the n-type GaAs substrate 29, and the surface of the light emitting layer constituting portion 20 of the semiconductor light emitting device is formed as shown in FIG. It is possible to form a concavo-convex surface having a plurality of peak portions parallel to each other in two directions orthogonal to each other as shown, and a trough portion of a quadrangular pyramid opening 57 shape located in the middle of the peak portions.

  In the manufacturing process of the semiconductor light emitting device, the resist 31 is formed in a dot shape at the position where the apex of the four-sided pyramid on the n-type GaAs substrate 29 is to be formed. For example, the resist 31 has a length and width of about 1 μm or less and a distance of about 5 μm. Etching is performed in the same manner as in Example 2 to form a quadrangular pyramid having the apex at the position of the resist 31 and the base of the line connecting the nearest resists 31, thereby forming an uneven surface. In the following, it is possible to produce a semiconductor light emitting device having an uneven surface in which a quadrangular pyramid opening is formed on the surface of the light emitting layer constituting portion 20, almost the same as the manufacturing process of the semiconductor light emitting device 2. Note that the adhesive layer 22a made of p-type InGaP is grown thicker than in the first embodiment.

  When the semiconductor light emitting element of this modification produced through the same manufacturing process as in Example 2 is assembled into a semiconductor light emitting device and the same current as in Example 2 is injected, the same as the semiconductor light emitting device obtained in Example 2 A bright semiconductor light emitting device can be obtained. Since it can be manufactured through almost the same process as in Example 2, it is possible to select the semiconductor light-emitting element 2 of Example 2 or the semiconductor light-emitting element of this modification while looking at the yield and the like.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the embodiment, the description has been given of the case where the concavo-convex surface has a shape in which the surface connecting the peak and the valley is a flat surface and the corners are pointed. However, after a crystal growth process, a heat treatment process, or the like, there is a possibility that the corner portion formed by the faces is rounded and becomes a smooth curved surface. Moreover, the longer the time of exposure to a high temperature atmosphere, the higher the possibility that the corners will be rounded. Therefore, as long as the uneven surface has a height difference, the corners may be rounded.

  Moreover, in Example 1, although the peak part and the trough part showed the example parallel to the side surface of a semiconductor light-emitting device, even if it makes a slope, for example, 45 degrees, with respect to a side surface, a peak part and a trough part are made | formed. There is no problem.

  Further, in the second embodiment, the quadrangular pyramid has shown an example in which the bottom surfaces are arranged in a grid pattern, but the bottom surfaces may be arranged in a relationship in which they are translated by a certain distance from each other.

  Moreover, although the example which uses a p-type GaP board | substrate was shown as a semiconductor substrate transparent to the light light-emitted in a light emitting layer structure part, if it is a semiconductor substrate which is transparent to the light emission wavelength and has electroconductivity, other than GaP It can be anything.

  In addition, the semiconductor light emitting device has been shown to be finished in a structure called a shell type (or radial type). However, the semiconductor light emitting device is a surface mount type having a reflective surface whose opening diameter increases toward the direction of light emission. There is no problem.

The present invention can be configured as described in the following supplementary notes.
(Additional remark 1) On the 1st semiconductor substrate in which the 1st conductivity type uneven surface was formed, the said 1st conductivity type clad layer, active layer, and 2nd conductivity which can emit light with a fixed wavelength and which have an uneven surface A step of forming a light emitting layer constituting portion in which a cladding layer of a mold and an adhesive layer of the second conductivity type are sequentially provided, a step of flattening the uneven surface of the surface of the adhesive layer by a heat treatment, and a flattening Bonding the bonded surface to the surface of the adhesive layer that is transparent to the wavelength of the second conductivity type and performing a heat treatment; and joining and integrating the first And a step of removing the semiconductor substrate, the light emitting layer constituting portion, and the second conductive type substrate from the second conductive type substrate to the light emitting layer constituting portion. A method for manufacturing a semiconductor light emitting device.

(Additional remark 2) The said 2nd conductivity type board | substrate is a manufacturing method of the semiconductor light-emitting device of Additional remark 1 which consists of GaP.

(Additional remark 3) The said planarization is a manufacturing method of the semiconductor light-emitting element of Additional remark 1 or 2 performed by the mass transport method.

BRIEF DESCRIPTION OF THE DRAWINGS The structure of the semiconductor light-emitting device based on Example 1 of this invention is shown typically, FIG.1 (a) is a top view, FIG.1 (b) is the cross section along the AA of Fig.1 (a). FIG. 1 and FIG. 1C are perspective views schematically showing the uneven shape of the surface portion of the broken-line circle B in FIG. It is layer structure sectional drawing which shows typically the manufacturing method of the semiconductor light-emitting device based on Example 1 of this invention in order of a process. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a layer structure schematically showing a method for manufacturing a semiconductor light emitting element according to Example 1 of the present invention in the order of steps. It is sectional drawing which shows typically the structure of the semiconductor light-emitting device which mounted the semiconductor light-emitting device based on Example 1 of this invention. FIGS. 5A and 5B schematically show the structure of a semiconductor light emitting device according to Example 2 of the present invention, FIG. 5A is a plan view, and FIG. 5B is a cross section taken along line CC in FIG. FIG. 5 (c) is a perspective view schematically showing the uneven shape of the surface portion of the broken-line circle D in FIG. 5 (a), and FIG. 5 (d) shows the concave and convex portions of the uneven shape in FIG. 5 (c). It is a perspective view which shows typically the uneven | corrugated shape in the relationship to reverse.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Semiconductor light-emitting device 10 p-type GaP board | substrate 13, 33a, 33b, 53 Uneven surface 14, 54 Mountain part 15, 55 Valley part 20 Light-emitting layer structure part 22, 22a Adhesive layer 23 p-type clad layer 24 Active layer 25 n Type cladding layer 26 Etching stop layer 27 Buffer layer 29 N type GaAs substrate 31 Resist 35 Bonding surface 41 N side electrode 43 P side electrode 45 Angle 46 Height difference 57 Four pyramid opening 61 Header 63 Cup part 65, 66 Lead 68 Conductivity Adhesive 69 Au wire 71 Sealing resin 80 Semiconductor light emitting device

Claims (5)

An active layer having a concavo-convex surface on a first main surface and a second main surface opposite to the first main surface, a surface connected to the first main surface side and distant from the first main surface A first conductivity type first growth layer having an uneven surface with the same period as the uneven surface, and a surface connected to the second main surface side and distant from the second main surface is substantially flat. A light-emitting layer constituting section comprising a second growth layer of the second conductivity type, which is capable of emitting light at a specific wavelength;
A first conductive side electrode formed on a surface of the first growth layer facing the active layer;
A semiconductor substrate of the second conductivity type that is bonded to the second growth layer of the light emitting layer constituting section and is substantially transparent to the wavelength;
A second conductive side electrode formed on a surface of the semiconductor substrate facing the second growth layer;
A semiconductor light emitting element comprising:   2. The semiconductor according to claim 1, wherein the uneven surface of the first growth layer has a plurality of convex portions arranged in parallel in one direction and a concave portion located in the middle of the adjacent mountain portions. Light emitting element.   2. The semiconductor light emitting element according to claim 1, wherein the uneven surface of the first growth layer has one of a plurality of pyramids, cones, pyramids, and truncated cones.   The concavo-convex surface of the first growth layer has a plurality of convex portions parallel to each other in two directions orthogonal to each other and a concave portion located in the middle of the peak portion. Semiconductor light emitting device. The first conductive type cladding layer, the active layer, and the second conductive type clad layer having a concavo-convex surface capable of emitting light at a predetermined wavelength on the first semiconductor substrate on which the concavo-convex surface of the first conductivity type is formed. And forming a light emitting layer constituent part in which the adhesive layer of the second conductivity type is provided in order,
Flattening the uneven surface of the surface of the adhesive layer by heat treatment;
Bonding a bonded surface to the surface of the flattened adhesive layer by bonding a transparent substrate to the wavelength of the second conductivity type and performing a heat treatment;
Of the first semiconductor substrate, the light emitting layer constituting portion, and the second conductivity type substrate that are integrated by bonding, the remaining portions from the second conductivity type substrate to the light emitting layer constituting portion are left, and the rest Removing, and
The manufacturing method of the semiconductor light-emitting device characterized by the above-mentioned.

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