JP5396526B2 - Semiconductor light emitting device - Google Patents

Description

  The present invention relates to a semiconductor light-emitting device, and more particularly to a semiconductor light-emitting device characterized in that a light-emitting diode having a metal reflection layer and an opaque substrate layer are attached by wafer bonding technology.

  In order to increase the brightness of a light emitting diode (LED), a metal reflection layer is provided as a light reflection layer between a substrate and an active layer composed of a multi-quantum well (MQW) layer. The structure to be formed has been proposed. As a method for forming such a metal reflective layer, for example, a wafer bonding (sticking) technique for a substrate of a light emitting diode layer has been disclosed (see, for example, Patent Document 1 and Patent Document 2).

  Patent Document 1 and Patent Document 2 can manufacture a light emitting diode having desired mechanical properties and translucency, and can minimize the resistivity of the interface between the transparent layer and the growth layer. In order to provide a method for manufacturing a light emitting diode, a light emitting diode layer is sequentially grown on a temporary growth substrate, a light emitting diode structure having a relatively thin layer is formed, and then the temporary growth substrate is removed to temporarily grow the light emitting diode layer. Instead of the substrate, a light-emitting diode is manufactured by wafer-bonding a conductive and translucent substrate to a light-emitting diode layer serving as a lower buffer layer at that position. In Patent Document 1 and Patent Document 2, a transparent substrate such as GaP or sapphire is applied to the substrate used for pasting.

  24 to 26 show a schematic cross-sectional structure of a conventional semiconductor light emitting device formed by a wafer bonding technique.

  For example, as shown in FIG. 24, a conventional semiconductor light emitting device includes an Au—Sn alloy layer 14 disposed on a GaAs substrate 15, a barrier metal layer 13 disposed on the Au—Sn alloy layer 14, and a barrier. P-type cladding layer 10 disposed on metal layer 13, MQW layer 9 disposed on p-type cladding layer 10, n-type cladding layer 8 disposed on MQW layer 9, and n-type cladding layer 8 And a window layer 7 disposed thereon.

  In the conventional semiconductor light emitting device shown in FIG. 24, the metal used for pasting is an Au—Sn alloy. Since the Au—Sn alloy has a low melting point, the Au—Sn alloy on the epitaxial growth layer side and the Au—Sn alloy on the GaAs substrate 15 side constituting the LED can be melted and pasted at a low temperature.

  However, when the Au—Sn alloy layer 14 is used, since thermal diffusion of Sn occurs, it is necessary to insert a barrier metal layer 13 as shown in FIG. 24 in order to prevent the diffusion of Sn. Further, the Au—Sn alloy layer 14 has a problem that the light reflectance is poor.

  For example, as shown in FIG. 25, another conventional semiconductor light emitting device includes a metal reflection layer 16 disposed on a GaAs substrate 15, a p-type cladding layer 10 disposed on the metal reflection layer 16, and a p-type. An MQW layer 9 disposed on the cladding layer 10, an n-type cladding layer 8 disposed on the MQW layer 9, and a window layer 7 disposed on the n-type cladding layer 8 are provided. In the conventional semiconductor light emitting device shown in FIG. 25, the metal reflection layer 16 made by pasting the GaAs substrate 15 absorbs light at the interface between the metal and the semiconductor and cannot efficiently reflect the light. There is a point. That is, there is a problem that light absorption occurs at the interface between the p-type cladding layer 10 and the metal reflection layer 16.

  In order to increase the brightness of a semiconductor light emitting device (LED), there is also a method in which a distributed black reflection (DBR) layer is provided between a GaAs substrate and an active layer (MQW) as a light reflection layer. In an LED without a DBR structure, light emitted from the MQW layer is absorbed by the GaAs substrate and becomes dark. Therefore, DBR is used as a light reflection layer in order to increase the brightness of LEDs using a GaAs substrate.

  That is, another conventional semiconductor light emitting device includes, as shown in FIG. 26, a DBR layer 19 disposed on a GaAs substrate 15, a p-type cladding layer 10 disposed on the DBR layer 19, and a p-type cladding. An MQW layer 9 disposed on the layer 10, an n-type cladding layer 8 disposed on the MQW layer 9, and a window layer 7 disposed on the n-type cladding layer 8 are provided. The conventional semiconductor light emitting device shown in FIG. 26 uses a DBR layer 19 as a light reflection layer between the GaAs substrate 15 and the MQW layer 9, but the DBR layer 19 reflects only light incident from one direction. When the incident angle changes, the DBR does not reflect light, and light incident from other angles is not reflected by the DBR layer 19 and is transmitted. For this reason, the transmitted light is absorbed by the GaAs substrate 15 and there is a problem that the light emission luminance of the semiconductor light emitting element (LED) is lowered.

  When a conventional semiconductor light emitting device formed by wafer bonding technology uses an Au—Sn alloy layer as a metal used for pasting, it is necessary to insert a barrier metal layer in order to prevent thermal diffusion of Sn. Further, the Au—Sn alloy layer has poor light reflectivity.

  Even if the metal reflective layer is formed by attaching the substrate, light absorption occurs at the interface between the metal and the semiconductor, and light cannot be efficiently reflected.

  In addition, when a DBR layer is used as the reflective layer, the DBR layer reflects only light incident from one direction, and if the incident angle changes, it is transmitted without being reflected by the DBR layer and absorbed by the GaAs substrate. , LED emission brightness decreases.

  Furthermore, conventional semiconductor light-emitting elements formed by wafer bonding technology have problems of peeling when heated to high temperatures due to differences in thermal expansion coefficient and adhesion problems when a semiconductor substrate, insulating film, and metal layer are attached. There is.

  Further, a semiconductor light emitting element and a manufacturing structure thereof for attaching a stacked body of a semiconductor light emitting element and a semiconductor substrate using an adhesive instead of the wafer bonding technique are also disclosed (for example, see Patent Document 3).

JP-A-6-302857 US Pat. No. 5,376,580 JP 2005-223207 A

  An object of the present invention is to provide a high-intensity semiconductor light-emitting device by using a non-transparent semiconductor substrate such as GaAs or Si and bonding the substrate with good adhesion using a wafer bonding technique and forming a metal reflective layer. There is to do.

  It is another object of the present invention to provide a high-intensity semiconductor light emitting device that can reflect light at any angle by using a metal layer instead of DBR as a light reflection layer.

According to an aspect of the present invention for achieving the above object, a substrate having a groove formed on a surface thereof, a first metal layer formed on the surface of the substrate on which the groove is formed, and the first metal A second metal layer formed on the layer, and a semiconductor layer formed on the second metal layer and including a light emitting layer, and between the first metal layer and the second metal layer of the groove. There is provided a semiconductor light emitting device characterized in that an air gap exists .

  According to the semiconductor light emitting device of the present invention, in order to solve the problem of Sn diffusion due to the Au—Sn alloy layer, the metal layer made of Au is used, and the epitaxial growth layer and the semiconductor substrate are adhered to each other by using a wafer bonding technique. By sticking well, a barrier metal becomes unnecessary, and by using a metal layer made of Au, a metal reflective layer having a good light reflectance can be formed in the structure on the LED side, so that the brightness of the LED is increased. be able to.

  According to the semiconductor light emitting device of the present invention, in order to prevent light absorption to the GaAs substrate, the light is totally reflected using a metal in the reflection layer, absorption to the GaAs substrate is prevented, and light of all angles is reflected. Therefore, the brightness of the LED can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS It is principle explanatory drawing of the semiconductor light-emitting device which concerns on embodiment of this invention, and its manufacturing method, (a) Typical cross-section figure of GaAs substrate, (b) Typical cross-section figure after wafer bonding, (c) The typical cross-section figure after chip-ization. 1 is a schematic cross-sectional structure diagram of a p-type GaAs substrate applied to a semiconductor light emitting element and a method for manufacturing the same according to a first embodiment of the present invention. 1 is a schematic cross-sectional structure diagram of an n-type GaAs substrate applied to a semiconductor light emitting element and a method for manufacturing the same according to a first embodiment of the invention. The typical cross-section figure of LED applied to the semiconductor light-emitting device concerning the 1st Embodiment of this invention, and its manufacturing method. 1 is a schematic cross-sectional structure diagram of a semiconductor light emitting element according to a first embodiment of the present invention. The typical cross-section figure of LED applied to the semiconductor light-emitting device concerning the 2nd Embodiment of this invention, and its manufacturing method. The typical cross-section figure of LED applied to the semiconductor light-emitting device concerning the modification of the 2nd Embodiment of this invention, and its manufacturing method. The typical cross-section figure of the semiconductor light-emitting device which concerns on the 2nd Embodiment of this invention. The typical cross-section figure of the GaAs substrate applied to the semiconductor light-emitting device concerning the 3rd Embodiment of this invention, and its manufacturing method. The typical cross-section figure of LED applied to the semiconductor light-emitting device concerning the 3rd Embodiment of this invention, and its manufacturing method. The typical cross-section figure of the semiconductor light-emitting device which concerns on the 3rd Embodiment of this invention. The typical cross-section figure of the Si substrate applied to the semiconductor light-emitting device which concerns on the 4th Embodiment of this invention, and its manufacturing method. The typical cross-section figure of LED applied to the semiconductor light-emitting device concerning the 4th Embodiment of this invention, and its manufacturing method. The typical plane pattern structure figure of LED applied to the semiconductor light-emitting device concerning the 4th Embodiment of this invention, and its manufacturing method. The another typical plane pattern structure figure of LED applied to the semiconductor light-emitting device concerning the 4th Embodiment of this invention, and its manufacturing method. The typical cross-section figure explaining 1 process of the manufacturing method of the semiconductor light-emitting device concerning the 4th Embodiment of this invention. The typical cross-section figure explaining 1 process of the manufacturing method of the semiconductor light-emitting device concerning the 4th Embodiment of this invention. The typical cross-section figure explaining 1 process of the manufacturing method of the semiconductor light-emitting device concerning the 4th Embodiment of this invention. The typical cross-section figure explaining 1 process of the manufacturing method of the semiconductor light-emitting device concerning the 4th Embodiment of this invention. The typical cross-section figure explaining 1 process of the manufacturing method of the semiconductor light-emitting device concerning the 4th Embodiment of this invention. The typical cross-section figure explaining 1 process of the manufacturing method of the semiconductor light-emitting device concerning the 4th Embodiment of this invention. The typical cross-section figure explaining 1 process of the manufacturing method of the semiconductor light-emitting device which concerns on the modification of the 4th Embodiment of this invention. The typical cross-section figure explaining 1 process of the manufacturing method of the semiconductor light-emitting device which concerns on another modification of the 4th Embodiment of this invention. The typical cross-section figure of the conventional semiconductor light-emitting device. FIG. 6 is another schematic cross-sectional structure diagram of a conventional semiconductor light emitting device. FIG. 6 is still another schematic cross-sectional structure diagram of a conventional semiconductor light emitting device.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and different from the actual ones. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the embodiment described below exemplifies an apparatus and a method for embodying the technical idea of the present invention. The technical idea of the present invention is the arrangement of each component as described below. It is not something specific. The technical idea of the present invention can be variously modified within the scope of the claims.

[First embodiment]
(Element structure)
FIG. 1 is a diagram illustrating the principle of a semiconductor light emitting device and a method for manufacturing the same according to an embodiment of the present invention. FIG. 1A is a schematic cross-sectional structure diagram of a GaAs substrate.

  As shown in FIG. 1A, a p-type or n-type GaAs substrate (3, 6) is used for a p-type or n-type GaAs substrate applied to a semiconductor light emitting device and a method for manufacturing the same according to an embodiment of the present invention. And a metal layer 1 disposed on the surface of a p-type or n-type GaAs layer (3, 6) in which stripe-like grooves having a pitch L and a width W are formed. The width W of the stripe groove is, for example, about 10 μm, about 30 μm, or about 60 μm, and the pitch L is, for example, about 100 μm, 200 μm, 410 μm, 1000 μm, or 2000 μm. The groove is not limited to a stripe shape, and may be a lattice shape, a dot shape, a spiral shape, a hexagonal pattern shape, or the like. Further, the depth of the groove is formed to be the same as or shallower than the width W of the stripe.

  FIG. 1B shows a schematic cross-sectional structure of a semiconductor light emitting element formed by bonding the GaAs substrate shown in FIG. 1A and an LED to each other by a wafer bonding technique. The LED side is shown by, for example, a p-type cladding layer 10 formed by epitaxial growth and a metal layer 12 formed on the p-type cladding layer 10, and other active layers are not shown. The metal layer 1 disposed on the surface of the GaAs layer (3, 6) is used to attach the GaAs substrate and the LED, and an air gap (gap) 40 between the metal layer 1 and the metal layer 12 in the groove portion. Exists.

  That is, by forming such a groove on the surface of the GaAs substrate, when the LED is attached to the GaAs substrate by wafer bonding technology, an air escape path can be created and stress generated by thermal expansion during high temperature heating can be reduced. it can. As a result, it is possible to prevent peeling between layers due to differences in thermal expansion coefficients of the semiconductor substrate, the insulating film, and the metal layer.

  FIG. 1C shows a schematic cross-sectional structure view after further chip formation. An air gap 40 formed in a stripe-shaped groove formed on the surface of a p-type or n-type GaAs substrate is included in the completed chip. If the pitch L is large, the air gap 40 may not be included in the completed chip.

  The conductivity type of the GaAs substrate applied to the semiconductor light emitting device and the manufacturing method thereof according to the first embodiment of the present invention can be applied to either p-type or n-type. FIG. 2 shows a schematic cross-sectional structure of a p-type GaAs substrate applied to the semiconductor light emitting device and the manufacturing method thereof according to the first embodiment of the present invention, and FIG. 3 shows a schematic cross-section of the n-type GaAs substrate. The structure is shown. FIG. 4 shows a schematic cross-sectional structure of an LED applied to the semiconductor light emitting device and the method for manufacturing the same according to the first embodiment of the present invention.

  FIG. 5 shows a semiconductor according to the first embodiment of the present invention formed by bonding the p-type to n-type GaAs substrate shown in FIGS. 2 to 3 and the LED shown in FIG. 4 to each other by a wafer bonding technique. 1 shows a schematic cross-sectional structure of a light-emitting element.

  As shown in FIG. 2, the p-type GaAs substrate applied to the semiconductor light emitting device and the manufacturing method thereof according to the first embodiment of the present invention includes a p-type GaAs layer 3 having a plurality of grooves formed on the surface, The metal buffer layer 2 disposed on the surface of the p-type GaAs layer 3, the sidewall of the groove, and the bottom surface of the groove, the metal layer 1 disposed on the metal buffer layer 2, and the rear surface of the p-type GaAs layer 3 A metal buffer layer 4 and a metal layer 5 disposed on the surface of the metal buffer layer 4 opposite to the p-type GaAs layer 3 are provided.

  As shown in FIG. 3, the n-type GaAs substrate applied to the semiconductor light emitting device and the manufacturing method thereof according to the first embodiment of the present invention includes an n-type GaAs layer 6 having a plurality of grooves formed on the surface, The metal buffer layer 2 disposed on the surface of the n-type GaAs layer 6, the sidewall of the groove, and the bottom surface of the groove, the metal layer 1 disposed on the metal buffer layer 2, and the rear surface of the n-type GaAs layer 6 A metal buffer layer 4 and a metal layer 5 disposed on the surface of the metal buffer layer 4 opposite to the n-type GaAs layer 6 are provided.

  In the structure of FIG. 2, the metal layers 1 and 5 are all formed of an Au layer, and the metal buffer layers 2 and 4 can be formed of, for example, an AuBe layer in order to make contact with the p-type GaAs layer 3. In the structure of FIG. 3, the metal layers 1 and 5 are all formed of an Au layer, and the metal buffer layers 2 and 4 can be formed of, for example, an AuGe layer in order to make contact with the n-type GaAs layer 6. .

  A schematic cross-sectional structure of an LED applied to the semiconductor light emitting device and the method for manufacturing the same according to the first embodiment of the present invention is arranged on a metal layer 12 and a metal layer 12, as shown in FIG. Metal contact layer 11, p-type cladding layer 10 disposed on metal contact layer 11, MQW layer 9 disposed on p-type cladding layer 10, and n-type cladding layer 8 disposed on MQW layer 9 And a window layer 7 disposed on the n-type cladding layer 8.

In the structure of FIG. 4, the metal layer 12 is formed of, for example, an Au layer. The metal contact layer is formed of, for example, an AuBe layer or an alloy layer of AuBe and Ni. The p-type cladding layer 10 is formed of, for example, a multilayer structure of an AlGaAs layer or an AlGaAs layer having a conductivity type of p ⁻ type and an AlGaAs layer having a conductivity type of p ⁺ type, and has a thickness of, for example, about 0.1 μm. It is. The MQW layer 9 has a multiple quantum well structure in which about 100 heterojunction pairs made of, for example, a GaAs / GaAlAs layer are stacked, and has a thickness of about 1.6 μm, for example. The n-type cladding layer 8 is formed of, for example, an n-type AlGaAs layer and has a thickness of about 0.1 μm, for example. The window layer 7 is composed of, for example, a multilayer structure of an AlGaAs layer and a GaAs layer formed on the multilayer structure of the AlGaAs layer, and the total thickness is about 0.95 μm.

  As shown in FIG. 5, the semiconductor light emitting device according to the first embodiment of the present invention includes a p-type to n-type GaAs substrate shown in FIGS. 2 to 3 and an LED structure shown in FIG. Paste each other by technology.

  That is, as shown in FIG. 5, the semiconductor light emitting device according to the first embodiment of the present invention includes a p (n) type GaAs layer 3 (6) having a plurality of grooves formed on the surface, and p (n). Metal buffer layer 2 disposed on the surface of the type GaAs layer 3 (6), the sidewall of the groove, and the bottom surface of the groove, the metal layer 1 disposed on the metal buffer layer 2, and the p (n) type GaAs layer 3 ( 6) p (n) type comprising a metal buffer layer 4 arranged on the back surface and a metal layer 5 arranged on the surface of the metal buffer layer 4 opposite to the p (n) type GaAs layer 3 (6). A GaAs substrate structure, a metal layer 12, a metal contact layer 11 disposed on the metal layer 12, and a p-type cladding layer disposed on the metal contact layer 11 are disposed on the p (n) GaAs substrate. 10, MQW layer 9 disposed on p-type cladding layer 10, and MQW An n-type cladding layer 8 disposed on the 9, composed of a LED structure comprising a window layer 7 disposed on the n-type cladding layer 8.

  In order to solve the problem of Sn diffusion from the Au—Sn alloy layer, using the metal layer 1 and the metal layer 12 disposed on the surface of the p (n) type GaAs layer 3 (6), p (n) A p-n-type GaAs layer 3 is formed by attaching an LED structure composed of a type GaAs substrate structure and an epitaxially grown layer and an air gap 40 between the first metal layer 1 and the metal layer 12 in the groove. Adhesion between the metal layer 1 and the metal layer 12 disposed on the surface of (6) can be kept good, and it is possible to form a metal reflection layer having a high reflectance without using a barrier metal. .

  The metal reflection layer is formed in advance by the metal layer 12 disposed on the LED structure side. Since the mirror surface is formed by the interface between the p-type cladding layer 10 and the metal layer 12, the emitted light from the LED is reflected on the mirror surface. The metal contact layer 11 is a layer for making ohmic contact between the metal layer 12 and the p-type cladding layer 10, but is interposed at the interface between the metal layer 12 and the p-type cladding layer 10 to form a part of the mirror surface. doing.

  As shown in FIG. 5, the semiconductor light emitting device according to the first embodiment of the present invention is formed by forming both the metal layer 1 and the metal layer 12 with an Au layer, so that the metal layer 1 on the GaAs substrate side and the epitaxial growth layer are formed. The metal layer 12 on the LED structure side can be attached by thermocompression bonding.

  The pasting condition is, for example, about 250 ° C. to 700 ° C., desirably 300 ° C. to 400 ° C., and the pressure of thermocompression bonding is, for example, about 10 MPa to 20 MPa. By providing the air gap 40, the contact area between the metal layer 1 and the metal layer 12 is reduced as compared with the structure in which the entire surface is in close contact. As a result, by providing the air gap 40, the thermocompression bonding pressure is applied to the contact area between the metal layer 1 and the metal layer 12 whose contact area is relatively reduced. At the time of thermocompression bonding of the metal layer 12, the bonding strength is increased. Therefore, when the p (n) type GaAs substrate structure and the LED structure composed of the epitaxial growth layer are attached, the air gap 40 exists, so that the metal disposed on the surface of the p (n) type GaAs layer 3 (6). Good adhesion between the layer 1 and the metal layer 12 can be maintained.

  According to the semiconductor light emitting device according to the first embodiment of the present invention, the GaAs substrate structure and the LED structure can be bonded using the wafer bonding technique while maintaining good adhesion, and the metal made of Au. By using the layer 12, a metal reflective layer having a good light reflectance can be formed in the structure on the LED side, so that the brightness of the LED can be increased.

[Second Embodiment]
(Element structure)
FIG. 6 shows a schematic cross-sectional structure of an LED applied to the semiconductor light emitting device and the method for manufacturing the same according to the second embodiment of the present invention. FIG. 7 shows a schematic cross-sectional structure of an LED applied to a semiconductor light emitting device and a method for manufacturing the same according to a modification of the second embodiment of the present invention.

  FIG. 8 is a schematic cross-sectional structure of a semiconductor light emitting device according to the second embodiment of the present invention formed by bonding the p-type to n-type GaAs substrate 15 and the LED shown in FIG. Indicates. In FIG. 8, a metal layer made of, for example, an Au layer disposed on the GaAs substrate 15 is not shown. Alternatively, it is also possible to attach the GaAs substrate 15 and the LED structure only with the metal layer 12 without arranging a metal layer such as an Au layer on the GaAs substrate 15.

  As shown in FIG. 6, the LED applied to the semiconductor light emitting device and the manufacturing method thereof according to the second embodiment of the present invention has a metal layer 12 and a metal contact disposed on the metal layer 12 and patterned. Layer 11 and insulating layer 17, p-type cladding layer 10 disposed on patterned metal contact layer 11 and insulating layer 17, MQW layer 9 disposed on p-type cladding layer 10, and MQW layer 9 And an window layer 7 disposed on the n-type cladding layer 8.

In the structure of FIG. 6, the metal layer 12 is formed of, for example, an Au layer, and has a thickness of about 2.5 to 5 μm, for example. The metal contact layer 11 is formed of, for example, an AuBe layer or an alloy layer of AuBe and Ni, and has a thickness that is about the same as that of the insulating layer 17 and about 450 nm. The insulating layer 17 is formed of, for example, a silicon oxide film, a silicon nitride film, a SiON film, a SiOxNy film, or a multilayer film thereof. The p-type cladding layer 10 is formed of, for example, a multilayer structure of an AlGaAs layer or an AlGaAs layer having a conductivity type of p ⁻ type and an AlGaAs layer having a conductivity type of p ⁺ type, and has a thickness of, for example, about 0.1 μm. It is. The MQW layer 9 has a multiple quantum well structure in which about 100 heterojunction pairs made of, for example, a GaAs / GaAlAs layer are stacked, and has a thickness of about 1.6 μm, for example. The n-type cladding layer 8 is formed of, for example, an n-type AlGaAs layer and has a thickness of about 0.1 μm, for example. The window layer 7 is composed of, for example, a multilayer structure of an AlGaAs layer and a GaAs layer formed on the multilayer structure of the AlGaAs layer, and the total thickness is about 0.95 μm.

(Modification of the second embodiment)
As shown in FIG. 7, an LED applied to a semiconductor light emitting device and a method for manufacturing the same according to a modification of the second embodiment of the present invention includes a metal layer 12 and a metal buffer disposed on the metal layer 12. A layer 18, a patterned metal contact layer 11 and an insulating layer 17 disposed on the metal buffer layer 18, a p-type cladding layer 10 disposed on the patterned metal contact layer 11 and the insulating layer 17, and p An MQW layer 9 disposed on the mold cladding layer 10, an n-type cladding layer 8 disposed on the MQW layer 9, and a window layer 7 disposed on the n-type cladding layer 8 are provided.

  In the structure of FIG. 7, the metal buffer layer 18 is formed of, for example, an Ag, Al, Ni, Cr, or W layer. Since the metal layer 12 made of Au layer absorbs blue light and ultraviolet light, it is desirable to include a metal buffer layer 18 made of Ag, Al or the like in order to reflect such short wavelength light. In the structure of FIG. 7, the layers other than the metal buffer layer 18 are formed in the same manner as the structure of FIG.

  As shown in FIG. 8, the semiconductor light emitting device according to the second embodiment of the present invention is formed by bonding the LED structure shown in FIGS. 6 to 7 and the GaAs substrate 15 to each other by a wafer bonding technique.

  That is, the semiconductor light emitting device according to the second embodiment of the present invention is disposed on the GaAs substrate 15, the metal layer 12 disposed on the GaAs substrate 15, and the metal layer 12, as shown in FIG. The metal buffer layer 18, the metal contact layer 11 and the insulating layer 17 which are arranged and patterned on the metal buffer layer 18, and the p-type cladding layer 10 which is arranged on the patterned metal contact layer 11 and the insulating layer 17 An LED structure including an MQW layer 9 disposed on the p-type cladding layer 10, an n-type cladding layer 8 disposed on the MQW layer 9, and a window layer 7 disposed on the n-type cladding layer 8. Consists of

  By using the metal layer 12 and affixing an LED structure composed of a GaAs substrate 15 and an epitaxial growth layer, it is possible to form a metal reflection layer with good reflectivity. The metal reflection layer is formed in advance by the metal layer 12 disposed on the LED structure side. Since the mirror surface is formed by the interface between the insulating layer 17 and the metal layer 12 or the metal buffer layer 18, the emitted light from the LED is reflected on the mirror surface. The metal contact layer 11 is a layer for making ohmic contact between the metal layer 12 or the metal buffer layer 18 and the p-type cladding layer 10, and is interposed at the interface between the metal layer 12 and the p-type cladding layer 10 to provide insulation. It has the same thickness as the layer 17.

  When the pattern width of the metal contact layer 11 is wide, since a substantial light emitting region is limited, the area efficiency is lowered and the light emitting efficiency is reduced. On the other hand, when the pattern width of the metal contact layer 11 is narrow, the sheet resistance of the metal contact layer 11 increases and the forward voltage Vf of the LED increases, so that an optimum pattern width and pattern structure exist. In some pattern examples, there is a honeycomb pattern structure based on a hexagon or a dot pattern structure based on a circle. These pattern shapes will be described with reference to FIGS. 14 and 15 in relation to the fourth embodiment.

  In the semiconductor light emitting device according to the second embodiment of the present invention, as shown in FIG. 5, both the metal layer disposed on the GaAs substrate and the metal layer 12 disposed on the LED side are formed by the Au layer. Thus, the metal layer 12 (not shown) on the GaAs substrate side and the metal layer 12 on the LED structure side made of the epitaxial growth layer can be attached by thermocompression bonding.

  The pasting condition is, for example, about 250 ° C. to 700 ° C., desirably 300 ° C. to 400 ° C., and the pressure of thermocompression bonding is, for example, about 10 MPa to 20 MPa.

  According to the semiconductor light emitting device according to the second embodiment of the present invention, a transparent insulating layer is provided between the metal layer 12 or the metal buffer layer 18 serving as the metal reflection layer and the semiconductor layer such as the p-type cladding layer 10. By forming 17, the contact between the semiconductor layer such as the p-type cladding layer 10 and the metal layer 12 can be avoided, the absorption of light can be prevented, and a metal reflection layer with good reflectivity can be formed.

  A transparent insulating layer 17 is formed by patterning, and a metal contact layer 11 made of AuBe or the like is deposited by lift-off in order to take ohmic contact.

  Thereafter, an Au layer used for adhering to the GaAs substrate 15 is deposited on the insulating layer 17 to form the metal layer 12.

  According to the semiconductor light emitting device of the second embodiment of the present invention, the transparent insulating layer 17 is interposed between the metal reflective layer and the semiconductor layer, so that the semiconductor layer such as the p-type cladding layer 10 and the metal Since it is possible to avoid contact with the layer 12, prevent light absorption, and form a metal reflective layer with good reflectance, it is possible to increase the brightness of the LED.

  In addition, according to the semiconductor light emitting device according to the second embodiment of the present invention, by forming the metal buffer layer 18 made of Ag, Al, or the like between the insulating layer 17 and the metal layer 12, Au can be used. Light having a short wavelength such as ultraviolet light having a low reflectance can be efficiently reflected, and the brightness of the LED can be increased.

  Further, according to the semiconductor light emitting device according to the second embodiment of the present invention, light is not absorbed at the interface between the p-type cladding layer and the metal reflection layer, so that the brightness of the LED can be increased.

[Third embodiment]
(Element structure)
FIG. 9 shows a schematic cross-sectional structure of a GaAs substrate applied to the semiconductor light emitting device and the method for manufacturing the same according to the third embodiment of the present invention. FIG. 10 shows a schematic cross-sectional structure of an LED applied to the semiconductor light emitting device and the method for manufacturing the same according to the third embodiment of the present invention.

  FIG. 11 shows a semiconductor light emitting device according to a third embodiment of the present invention formed by bonding the GaAs substrate 15 having the metal layer 20 shown in FIG. 9 and the LED shown in FIG. 10 to each other by wafer bonding technology. The schematic cross-sectional structure of is shown.

  As shown in FIG. 9, the p-type or n-type GaAs substrate structure applied to the semiconductor light emitting device and the manufacturing method thereof according to the third embodiment of the present invention has a GaAs substrate 15 having a plurality of grooves formed on the surface. And a metal layer 20 disposed on the surface of the GaAs substrate 15, the sidewall of the groove, and the bottom of the groove.

  In the structure of FIG. 9, the metal layer 20 is formed of, for example, an Au layer.

  A schematic cross-sectional structure of an LED applied to a semiconductor light emitting device and a method for manufacturing the same according to a third embodiment of the present invention is arranged on a metal layer 12 and a metal layer 12, as shown in FIG. p-type cladding layer 10, MQW layer 9 disposed on p-type cladding layer 10, n-type cladding layer 8 disposed on MQW layer 9, and window layer 7 disposed on n-type cladding layer 8 Is provided.

In the structure of FIG. 10, the metal layer 12 is formed of, for example, an Au layer and has a thickness of, for example, about 1 μm. The p-type cladding layer 10 is formed by a multilayer structure of, for example, an AlGaAs layer or an AlGaAs layer having a conductivity type of p ⁻ -type and an AlGaAs layer having a conductivity type of p ⁺ -type. It is formed to about 0.1 μm. The MQW layer 9 has a multiple quantum well structure in which about 80 to 100 heterojunction pairs made of, for example, a GaAs / GaAlAs layer are stacked, and the total thickness is formed to be about 1.6 μm, for example. The n-type cladding layer 8 is formed of, for example, an n-type AlGaAs layer and has a thickness of about 0.1 μm, for example. The window layer 7 is composed of, for example, a multilayer structure of an AlGaAs layer and a GaAs layer formed on the multilayer structure of the AlGaAs layer, and the overall thickness is about 0.95 μm.

  As shown in FIG. 11, the semiconductor light emitting device according to the third embodiment of the present invention has a p-type to n-type GaAs substrate shown in FIG. 9 and an LED structure shown in FIG. Paste to form.

  That is, as shown in FIG. 11, the semiconductor light emitting device according to the third embodiment of the present invention includes a GaAs substrate 15 having a plurality of grooves formed on the surface, the surface of the GaAs substrate 15, the sidewalls of the grooves, and the grooves. A GaAs substrate structure including a metal layer 20 disposed on the bottom surface; a metal layer 12 disposed on the GaAs substrate structure; a p-type cladding layer 10 disposed on the metal layer 12; and a p-type cladding layer 10 The LED structure includes an MQW layer 9 disposed on top, an n-type cladding layer 8 disposed on the MQW layer 9, and a window layer 7 disposed on the n-type cladding layer 8.

  The metal reflection layer is formed in advance by the metal layer 12 disposed on the LED structure side. Since the mirror surface is formed by the interface between the p-type cladding layer 10 and the metal layer 12, the emitted light from the LED is reflected on the mirror surface.

  As shown in FIG. 11, the semiconductor light emitting device according to the third embodiment of the present invention is formed by forming both the metal layer 20 and the metal layer 12 with an Au layer, so that the metal layer 20 on the GaAs substrate side and the epitaxial growth layer are formed. The LED structure-side metal layer 12 is attached by thermocompression bonding, and an air gap 40 exists between the metal layer 20 and the metal layer 12 in the groove.

  The pasting condition is, for example, about 250 ° C. to 700 ° C., desirably 300 ° C. to 400 ° C., and the pressure of thermocompression bonding is, for example, about 10 MPa to 20 MPa. By providing the air gap 40, the contact area between the metal layer 20 and the metal layer 12 is reduced as compared with a structure in which the entire surface is in close contact. As a result, by providing the air gap 40, the pressure of the thermocompression bonding is pressurized to the contact area between the metal layer 20 and the metal layer 12 that have a relatively reduced contact area. At the time of thermocompression bonding of the metal layer 12, the bonding strength is increased. Therefore, when the GaAs substrate and the LED structure are attached, the air gap 40 is present, so that the adhesion between the metal layer 20 and the metal layer 12 disposed on the surface of the GaAs substrate can be kept good.

  According to the semiconductor light emitting device and the manufacturing method thereof according to the third embodiment of the present invention, in order to prevent light absorption into the GaAs substrate while maintaining good adhesion between the metal layer 20 and the metal layer 12, It is characterized in that light is totally reflected using a metal in the reflective layer to prevent absorption into the GaAs substrate. As a material of the semiconductor substrate to be pasted, an opaque semiconductor substrate material such as GaAs or Si is used.

  An Au layer is used as the metal layer 20 on the GaAs substrate 15 side, an Au layer is also used as the metal layer 12 on the LED side having an epitaxial growth layer, the metal layer 20 and the metal layer 12 are bonded, and the metal layer 12 used for bonding is A light reflection layer is used as the metal reflection layer.

  According to the semiconductor light emitting device and the method for manufacturing the same according to the third embodiment of the present invention, the GaAs substrate structure and the LED structure can be bonded using the wafer bonding technique while maintaining good adhesion, and GaAs In order to prevent light absorption to the substrate, the reflection layer is made of metal to totally reflect the light, preventing absorption to the GaAs substrate and reflecting light of all angles, thus increasing the brightness of the LED can do.

[Fourth embodiment]
(Element structure)
FIG. 12 shows a schematic cross-sectional structure of a silicon substrate applied to the semiconductor light emitting device and the method for manufacturing the same according to the fourth embodiment of the present invention. FIG. 13 shows a schematic cross-sectional structure of an LED applied to the semiconductor light emitting device and the method for manufacturing the same according to the fourth embodiment of the present invention. FIG. 14 shows a schematic planar pattern structure of an LED applied to the semiconductor light emitting device and the manufacturing method thereof according to the fourth embodiment of the present invention, and FIG. 15 shows another schematic planar pattern structure.

  As shown in FIG. 12, the silicon substrate 21 applied to the semiconductor light emitting device and the manufacturing method thereof according to the fourth embodiment of the present invention includes a silicon substrate 21 having a plurality of grooves formed on the surface, and a silicon substrate 21. , A titanium (Ti) layer 22 disposed on the side wall of the groove portion, and a bottom surface of the groove portion, and a metal layer 20 disposed on the surface of the titanium (Ti) layer 22.

  In the structure of FIG. 12, the thickness of the silicon substrate 21 is about 130 μm, for example, and the metal layer 20 is formed of, for example, an Au layer, and the thickness is about 2.5 μm.

  As shown in FIG. 13, the LED applied to the semiconductor light emitting device and the manufacturing method thereof according to the fourth embodiment of the present invention includes a GaAs substrate 23, an AlInGaP layer 24 disposed on the GaAs substrate 23, An n-type GaAs layer 25 disposed on the AlInGaP layer 24, an epitaxial growth layer 26 disposed on the n-type GaAs layer 25, a metal contact layer 11 and an insulating layer 17 disposed on the epitaxial growth layer 26 and patterned. A patterned metal contact layer 11 and a metal layer 12 disposed on the insulating layer 17.

  In the structure of FIG. 13, the GaAs substrate 23 has a thickness of about 300 μm, for example, and the AlInGaP layer 24 has a thickness of about 350 nm, for example. The n-type GaAs layer 25 functions as a contact layer between the GaAs substrate 23 and the epitaxial growth layer 26 via the AlInGaP layer 24, and has a thickness of about 500 nm, for example. The epitaxial growth layer 26 includes an n-type window layer and an n-type cladding layer made of an AlGaAs layer, an MQW layer made up of a plurality of pairs of GaAs / AlGaAs heterojunctions, an n-type cladding layer made of an AlGaAs layer, and an AlGaAs layer / GaP layer. A p-type window layer. The MQW layer has a multiple quantum well structure in which about 100 pairs of heterojunction pairs made of, for example, a GaAs / GaAlAs layer are stacked, and has a thickness of about 1.6 μm, for example.

  The metal contact layer 11 is formed of, for example, an AuBe layer or an alloy layer of AuBe and Ni, and has a thickness that is about the same as that of the insulating layer 17 and about 450 nm.

The metal contact layer 11 may be formed as a laminated structure of, for example, Au / AuBe—Ni alloy / Au. The insulating layer 17 is formed of, for example, a silicon oxide film, a silicon nitride film, a SiON film, a SiOxNy film, or a multilayer film thereof.

The metal layer 12 is formed of, for example, an Au layer, and has a thickness of about 2.5 to 5 μm, for example. The p-type cladding layer in the epitaxial growth layer 26 is formed of, for example, a multilayer structure of an AlGaAs layer or an AlGaAs layer having a conductivity type of p ⁻ type and an AlGaAs layer having a conductivity type of p ⁺ type, and has a thickness of, for example, about It is about 0.1 μm. The n-type cladding layer in the epitaxial growth layer 26 is formed of, for example, an n-type AlGaAs layer and has a thickness of, for example, about 0.1 μm. The n-type window layer is composed of, for example, a multilayer structure of an AlGaAs layer and a GaAs layer formed on the multilayer structure of the AlGaAs layer, and the total thickness is, for example, about 0.95 μm. The p-type window layer is composed of, for example, a multilayer structure of an AlGaAs layer and a GaP layer formed on the multilayer structure of the AlGaAs layer, and the total thickness is, for example, about 0.32 μm.

  As shown in FIG. 21, the semiconductor light emitting device according to the fourth embodiment of the present invention is formed by bonding the silicon substrate structure shown in FIG. 12 and the LED structure shown in FIG. 13 to each other by wafer bonding technology. To do.

  That is, as shown in FIG. 21, the semiconductor light emitting device according to the fourth embodiment of the present invention includes a silicon substrate 21 having a plurality of grooves formed on the surface, the surface of the silicon substrate 21, the sidewalls of the grooves, and the grooves. A silicon substrate structure composed of a titanium layer 22 disposed on the bottom surface and a metal layer 20 disposed on the titanium layer 22, a metal layer 12 disposed on the metal layer 20, and the metal layer 12 The frosted region 30 (exposed n-type GaAs layer 25 is formed on the exposed surface of the metal contact layer 11 and the insulating layer 17 which are arranged and patterned, and the metal contact layer 11 and the insulating layer 17 which are patterned and exposed. An epitaxial growth layer 26 having a region formed by frost treatment of the n-type GaAs and a patterned n-type GaAs disposed on the epitaxial growth layer 26 and patterned It comprises an LED structure comprising a layer 25 and a surface electrode layer 29 disposed on the n-type GaAs layer 25 and similarly patterned. In the silicon substrate structure, a titanium layer 27 and a back electrode layer 28 are disposed on the back surface of the silicon substrate 21. Further, a blocking layer 31 for preventing current concentration may be arranged between the epitaxial growth layer 26 and the n-type GaAs layer 25 as shown in FIGS. As the material of the blocking layer 31 in this case, GaAs can be applied, and the thickness is, for example, about 500 nm.

  Also in the semiconductor light emitting device according to the fourth embodiment of the present invention, as shown in FIG. 21, the metal layer 12 is used to attach the LED structure composed of the silicon substrate structure and the epitaxial growth layer, and the metal in the groove portion. Since the air gap 40 exists between the layer 20 and the metal layer 12, the adhesion between the metal layer 20 and the metal layer 12 disposed on the surface of the silicon substrate 21 can be kept good, and the reflectance This makes it possible to form a metal reflective layer with good quality.

  By providing the air gap 40, the contact area between the metal layer 20 and the metal layer 12 is reduced as compared with a structure in which the entire surface is in close contact. As a result, by providing the air gap 40, the thermocompression pressure is pressurized to the contact area between the metal layer 20 and the metal layer 12 whose contact area is relatively reduced. At the time of thermocompression bonding of the layer 12, the bonding strength is increased. Therefore, when the silicon substrate structure and the LED structure are attached, the air gap 40 is present, so that the adhesion between the metal layer 20 and the metal layer 12 disposed on the surface of the silicon substrate can be kept good.

  According to the semiconductor light emitting device of the fourth embodiment of the present invention, the silicon substrate structure and the LED structure can be attached while maintaining good adhesion by using the wafer bonding technique, and the metal layer made of Au. 12 can be used to form a metal reflective layer having a good light reflectance in the structure on the LED side, so that the brightness of the LED can be increased.

  The metal reflection layer is formed in advance by the metal layer 12 disposed on the LED structure side. Since the mirror surface is formed by the interface between the insulating layer 17 and the metal layer 12, the emitted light from the LED is reflected on the mirror surface. The metal contact layer 11 is a layer for making ohmic contact between the metal layer 12 and the epitaxial growth layer 26, and is interposed at the interface between the metal layer 12 and the epitaxial growth layer 26 and has a thickness similar to that of the insulating layer 17. Have.

(Plane pattern structure)
When the pattern width of the metal contact layer 11 is wide, since a substantial light emitting region is limited, the area efficiency is lowered and the light emitting efficiency is reduced. On the other hand, when the pattern width of the metal contact layer 11 is narrow, the sheet resistance of the metal contact layer 11 increases and the forward voltage Vf of the LED increases. For this reason, the optimum pattern width W and pattern pitch D1 exist. In some pattern examples, there is a honeycomb pattern structure based on a hexagon or a circular dot pattern structure based on a circular dot shape.

  The schematic planar pattern structure of the LED applied to the semiconductor light emitting device and the manufacturing method thereof according to the fourth embodiment of the present invention is a honeycomb pattern structure having a hexagonal basic structure as shown in FIG. Have. 14, the shape portion indicated by the width W indicates the pattern of the metal contact layer 11 formed of, for example, an AuBe layer or an alloy layer of AuBe and Ni in FIG. 13, and the hexagonal pattern having the width D1 is an insulating material. It corresponds to the portion of the layer 17 and represents a region where the emitted light from the LED is guided. The width D1 is about 100 μm, for example, and the line width W is about 5 μm to about 11 μm.

  Another schematic planar pattern structure of the LED applied to the semiconductor light emitting element and the manufacturing method thereof according to the fourth embodiment of the present invention is a dot pattern structure based on a circle as shown in FIG. Have. In FIG. 15, the shape portion indicated by the width d indicates the pattern of the metal contact layer 11 formed of, for example, an AuBe layer or an alloy layer of AuBe and Ni in FIG. 13, and is arranged at a pattern pitch having a width D2. Yes. In FIG. 15, a region other than the circular pattern portion having the width d and the pattern pitch D2 corresponds to the portion of the insulating layer 17 and represents a region where the emitted light from the LED is guided. The pattern pitch D2 is about 100 μm, for example, and the width d is about 5 μm to about 11 μm.

  In addition, the schematic planar pattern structure of the LED applied to the semiconductor light emitting device and the manufacturing method thereof according to the fourth embodiment of the present invention is not limited to the hexagonal honeycomb pattern and the circular dot pattern, but a triangle. A random pattern in which a pattern, a rectangular pattern, a hexagonal pattern, an octagonal pattern, a circular dot pattern, etc. are randomly arranged can also be applied.

  The schematic planar pattern structure of the LED applied to the semiconductor light emitting device according to the fourth embodiment of the present invention secures the area of the light guide region and does not decrease the light emission luminance from the LED. It is only necessary to secure a metal wiring pattern width that does not increase the forward voltage Vf.

(Production method)
A method for manufacturing a semiconductor light emitting element according to the fourth embodiment of the present invention will be described below.

  12 to 21 show a schematic cross-sectional structure for explaining one process of the method for manufacturing a semiconductor light emitting device according to the fourth embodiment of the present invention.

(A) First, as shown in FIG. 12, a silicon substrate structure for pasting and an LED structure for pasting as shown in FIG. 13 are prepared.

  First, stripe-like grooves having a pitch L and a width W are formed on the surface of the silicon substrate 21 by reactive ion etching (RIE) or wet etching. The width W of the stripe groove is, for example, about 10 μm, about 30 μm, or about 60 μm, and the pitch L is, for example, about 100 μm, 200 μm, 410 μm, 1000 μm, or 2000 μm. The groove is not limited to a stripe shape, and may be a lattice shape, a dot shape, a spiral shape, a hexagonal pattern shape, or the like. Further, the depth of the groove may be the same as or shallower than the width W of the stripe. Instead of the etching, a groove portion may be formed to a predetermined depth by applying a cutting technique using a laser beam, a cutting technique using a dicer, or the like using a YAG laser or the like.

  In the silicon substrate structure, a titanium layer 22 and a metal layer 20 made of Au or the like are sequentially formed on a silicon substrate 21 having a plurality of grooves formed on the surface by a sputtering method, a vacuum evaporation method, or the like.

  In the LED structure, the AlInGaP layer 24, the n-type GaAs layer 25, and the epitaxial growth layer 26 on the GaAs substrate 23 are formed by using molecular beam epitaxy (MBE), MOCVD (Metal Organic Chemical Vapor Deposition), or the like. Sequentially formed. Next, the metal contact layer 11 and the metal layer 12 are formed on the patterned insulating layer 17 on the epitaxial growth layer 26 using a lift-off method.

(B) Next, as shown in FIG. 16, the silicon substrate structure for pasting shown in FIG. 12 and the LED structure for pasting shown in FIG. 13 are pasted. In the attaching step, for example, using a press machine, the thermocompression bonding temperature is about 340 ° C., the thermocompression bonding pressure is about 18 MPa, and the thermocompression bonding time is about 10 minutes.

  As a result, as shown in FIG. 16, an air gap 40 is formed between the metal layer 20 and the metal layer 12 in the groove.

(C) Next, as shown in FIG. 17, a back electrode layer 28 made of a titanium layer 27 and Au or the like is sequentially formed on the back surface of the silicon substrate 21 using a sputtering method, a vacuum evaporation method, or the like. In the case where the titanium layer 27 is not interposed between the Au layer and the silicon substrate 21, if the sintering is performed to obtain an ohmic contact, the Au at the junction between the silicon substrate 21 and the Au layer becomes AuSi silicide, and the reflectance decreases. . Therefore, the titanium layer 27 is a metal for bonding the silicon substrate 21 and the Au layer. In order to prevent AuSi silicidation, tungsten (W) is required as a barrier metal, and as a structure at that time, it is necessary to form a metal layer from a substrate side with a silicon substrate / Ti / W / Au.

(D) Next, as shown in FIG. 18, after the back electrode layer 28 is protected with a resist or the like, the GaAs substrate 23 is removed by etching. For example, an etching solution composed of ammonia / hydrogen peroxide solution is used, and the etching time is about 65 to 85 minutes. Here, the AlInGaP layer 24 plays an important role as an etching stopper.

(E) Next, as shown in FIG. 19, the AlInGaP layer 24 is removed using a hydrochloric acid-based etchant. The etching time is, for example, about 1 minute and a half.

(F) Next, as shown in FIG. 20, the surface electrode layer 29 is formed by sputtering, vacuum deposition, or the like, and then patterned. The pattern of the surface electrode layer 29 is substantially matched with the pattern of the metal contact layer 11. As a material of the surface electrode layer 29, for example, a laminated structure made of Au / AuGe-Ni alloy / Au can be used. Here, the n-type GaAs layer 25 has a function of preventing the surface electrode layer 29 from peeling off.

(G) Next, as shown in FIG. 21, a frost process is performed to remove the n-type GaAs layer 25 other than the n-type GaAs layer 25 directly below the surface electrode layer 29. As conditions for the frost treatment, for example, a nitric acid-sulfuric acid based etching solution can be performed at about 30 ° C. to 50 ° C. for about 5 sec to 15 sec. As a pretreatment for the frost treatment, the n-type GaAs layer 25 can be etched using a thin solution of hydrofluoric acid to remove the GaO ₂ film formed on the surface. The etching time is about 3 minutes, for example.

  In place of the titanium layer 22 and the titanium layer 27, for example, tungsten (W) barrier metal, platinum (Pt) barrier metal, or the like can be used.

  As described above, as shown in FIG. 21, the semiconductor light emitting device according to the fourth embodiment of the present invention using the silicon substrate 21 having a plurality of grooves formed on the surface is completed.

(Modification of the fourth embodiment)
FIG. 22 shows a schematic cross-sectional structure for explaining one process of the method for manufacturing the semiconductor light emitting device according to the modification of the fourth embodiment of the present invention. FIG. 23 shows a schematic cross-sectional structure for explaining one step of a method for manufacturing a semiconductor light emitting element according to another modification of the fourth embodiment of the present invention.

  As shown in FIG. 22, the semiconductor light emitting device according to the modification of the fourth embodiment of the present invention has a GaAs substrate structure having the same structure as the silicon substrate structure shown in FIG. LED structures are formed by affixing each other by wafer bonding technology.

That is, the semiconductor light emitting device according to the fourth embodiment of the present invention, as shown in FIG.
On the GaAs substrate 15 having a plurality of grooves formed on the surface, a metal buffer layer (AuGe-Ni alloy layer) 32 disposed on the surface of the GaAs substrate 15, the sidewalls of the grooves, and the bottom surfaces of the grooves, and on the metal buffer layer 32 A GaAs substrate structure composed of a metal layer (Au layer) 33 to be disposed; a metal layer 12 disposed on the metal layer 33; and a patterned metal contact layer 11 and insulation disposed on the metal layer 12 The layer 17 is disposed on the patterned metal contact layer 11 and the insulating layer 17, and has a frosted region 30 (region formed by frosting the exposed n-type GaAs layer 25) on the exposed surface. On the epitaxial growth layer 26, the n-type GaAs layer 25 arranged and patterned on the epitaxial growth layer 26, and the n-type GaAs layer 25 It comprises an LED structure which is arranged and is composed of a similarly patterned surface electrode layer 29.

  In the GaAs substrate structure, a metal buffer layer (AuGe—Ni alloy layer) 34 and a back electrode layer 35 are disposed on the back surface of the GaAs substrate 15. Further, a blocking layer 31 for preventing current concentration may be disposed between the epitaxial growth layer 26 and the n-type GaAs layer 25 as shown in FIG. As the material of the blocking layer 31 in this case, GaAs can be applied, and the thickness is, for example, about 500 nm.

  Also in the semiconductor light emitting device according to the modification of the fourth embodiment of the present invention, the metal layer (Au layer) 33 and the metal layer 12 on the surface of the GaAs substrate 15 are used as shown in FIG. A metal layer 33 disposed on the surface of the GaAs substrate 15 is formed by attaching a substrate structure and an LED structure composed of an epitaxially grown layer, and having an air gap 40 between the metal layer 33 and the metal layer 12 in the groove. It is possible to maintain a good adhesion between the metal layer 12 and the metal layer 12 and to form a metal reflective layer having a good reflectivity. By providing the air gap 40, the contact area between the metal layer 33 and the metal layer 12 is reduced as compared with the structure in which the entire surface is in close contact. As a result, by providing the air gap 40, the pressure of the thermocompression bonding is pressurized to the contact area between the metal layer 33 and the metal layer 12 whose contact area is relatively reduced. At the time of thermocompression bonding of the layer 12, the bonding strength is increased.

  Therefore, when the GaAs substrate structure and the LED structure are attached, the air gap 40 exists, so that the adhesion between the metal layer 33 and the metal layer 12 disposed on the surface of the GaAs substrate can be kept good.

  The metal reflection layer is formed in advance by the metal layer 12 disposed on the LED structure side. Since the mirror surface is formed by the interface between the insulating layer 17 and the metal layer 12, the emitted light from the LED is reflected on the mirror surface. The metal contact layer 11 is a layer for making ohmic contact between the metal layer 12 and the epitaxial growth layer 26, and is interposed at the interface between the metal layer 12 and the epitaxial growth layer 26 and has a thickness similar to that of the insulating layer 17. Have.

  22 and FIG. 23, the metal buffer layer 34 formed on the back surface of the GaAs substrate 15 is formed of, for example, an AuGe—Ni alloy layer and has a thickness of about 100 nm. The back electrode layer 35 is formed of an Au layer and has a thickness of about 500 nm. The metal buffer layer 32 formed on the surface of the GaAs substrate 15 is formed of, for example, an AuGe-Ni alloy layer and has a thickness of about 100 nm. Furthermore, the metal layer 33 is formed of an Au layer and has a thickness of about 1 μm.

  Each step of the method for manufacturing a semiconductor light emitting device according to the fourth embodiment of the present invention shown in FIGS. 12 to 21 includes the steps of manufacturing a semiconductor light emitting device according to a modification of the fourth embodiment of the present invention. Since the method is the same, the description thereof is omitted.

  The schematic planar pattern structure of the LED applied to the semiconductor light emitting device and the method for manufacturing the semiconductor light emitting device according to the modification of the fourth embodiment of the present invention can also be applied to the structure similar to FIG.

  According to the semiconductor light emitting device according to the modification of the fourth embodiment of the present invention, the wafer bonding technique can be used to attach the GaAs substrate structure and the LED structure while maintaining good adhesion, and from Au By using the metal layer 12 to be formed, a metal reflection layer having a good light reflectance can be formed in the structure on the LED side, so that the brightness of the LED can be increased.

  Further, in the semiconductor light emitting device according to the fourth embodiment of the present invention and the modification thereof, Ag or Al is interposed between the insulating layer 17 and the metal layer 12 described in the modification of the second embodiment. It is also effective to form a metal buffer layer 18 (see FIG. 7) made of, for example. This is because, by forming the metal buffer layer 18 made of Ag, Al, or the like, Au can efficiently reflect light having a short wavelength such as ultraviolet rays having a low reflectance.

  According to the semiconductor light emitting device and the manufacturing method thereof according to the fourth embodiment of the present invention and the modification thereof, the epitaxial growth layer 26 is provided by interposing the transparent insulating layer 17 between the metal reflection layer and the semiconductor layer. And the metal layer 12 can be avoided, light absorption can be prevented, and a metal reflective layer with good reflectivity can be formed, so that the brightness of the LED can be increased.

  In addition, according to the semiconductor light emitting device and the manufacturing method thereof according to the fourth embodiment of the present invention and the modification thereof, the metal buffer made of Ag, Al, or the like between the insulating layer 17 and the metal layers 12 and 20. By forming the layer, Au can efficiently reflect light having a short wavelength such as ultraviolet light having a low reflectance, and the brightness of the LED can be increased.

  Further, according to the semiconductor light emitting device and the manufacturing method thereof according to the fourth embodiment of the present invention and the modification thereof, the contact between the epitaxial growth layer 26 and the metal layer 12 is avoided, and the interface between the epitaxial growth layer 26 and the metal reflection layer is avoided. Since no light is absorbed in the LED, it is possible to increase the brightness of the LED.

  According to the semiconductor light emitting device and the method for manufacturing the same according to the fourth embodiment of the present invention and the modification thereof, the reflection layer is made of metal to prevent light from being absorbed into the silicon substrate or the GaAs substrate. The light can be reflected to prevent absorption into the silicon substrate or the GaAs substrate, and light at any angle can be reflected, so that the brightness of the LED can be increased.

[Other embodiments]
As described above, the present invention has been described according to the first to fourth embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the semiconductor light emitting device and the manufacturing method thereof according to the first to fourth embodiments of the present invention, the silicon substrate and the GaAs substrate are mainly described as examples of the semiconductor substrate. However, the Ge, SiGe, SiC, GaN substrate, or A GaN epitaxial substrate on SiC or the like can be sufficiently used.

  As the semiconductor light emitting device according to the first to fourth embodiments of the present invention, description has been made mainly using the LED as an example. However, a laser diode (LD) may be configured, and in that case, distributed feedback is possible. A DFB (Distributed Feedback) LD, a distributed Bragg reflection type (DBR) LD, a surface emitting LD, or the like may be configured.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  The semiconductor light emitting device and the method for manufacturing the same according to the embodiment of the present invention can be used for general semiconductor light emitting devices such as LED devices and LD devices having an opaque substrate such as a GaAs substrate and a Si substrate.

1, 5, 12, 20, 33 ... metal layer (Au layer)
2, 4, 18 ... metal buffer layer 3 ... p-type GaAs layer 6 ... n-type GaAs layer 7 ... window layer 8 ... n-type cladding layer 9 ... multiple quantum well (MQW) layer 10 ... p-type cladding layer 11 ... metal contact Layer (AuBe-Ni alloy)
DESCRIPTION OF SYMBOLS 15, 23 ... GaAs substrate 17 ... Insulating layer 21 ... Silicon (Si) substrate 22, 27 ... Titanium (Ti) layer 24 ... AlInGaP layer 25 ... N-type GaAs layer 26 ... Epitaxial growth layer 29 ... Surface electrode layer 30 ... Frost processing area | region 31 ... Blocking layers 32, 34 ... Metal buffer layer (AuGe-Ni alloy)
28, 35 ... Back electrode layer 40 ... Air gap (air gap)

Claims (11)

A substrate having grooves on the surface;
A first metal layer formed on the surface of the substrate where the groove is formed;
A second metal layer formed on the first metal layer;
A semiconductor layer formed on the second metal layer and including a light emitting layer ;
A semiconductor light emitting device, wherein an air gap exists between the first metal layer and the second metal layer of the groove .   2. The semiconductor light emitting device according to claim 1, wherein the surface of the first metal layer is provided with an uneven portion reflecting the shape of the surface of the substrate on which the groove is formed. The surface of the second metal layer on the first metal layer side is planar.
The semiconductor light emitting element according to claim 2, wherein the semiconductor light emitting element is bonded to a contact surface between the convex portion of the first metal layer and the second metal layer.   4. The semiconductor light emitting element according to claim 1, wherein the first metal layer and the second metal layer are thermocompression bonded. 5. 5. The semiconductor light emitting element according to claim 1, wherein the groove has a width of 10 μm or more and about 60 μm or less. The semiconductor light emitting element according to claim 5, wherein a depth of the groove is equal to or less than a width of the groove. The semiconductor light emitting element according to claim 1, wherein the groove portion includes a plurality of adjacent groove portions, and an interval between the adjacent groove portions is 100 μm to 2000 μm. The semiconductor light emitting element according to any one of claims 1 to 7, wherein the pattern shape of the groove portion includes a stripe shape, a lattice shape, a dot shape, a spiral shape, and a hexagonal pattern shape. The semiconductor light-emitting element according to claim 1, wherein the substrate is made of an opaque material. The semiconductor light emitting device according to claim 9, wherein the substrate is made of GaAs or Si. The semiconductor light emitting device according to claim 1, wherein the substrate includes Ge, SiGe, SiC, or GaN.

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