JP2019220505A - Semiconductor light-emitting device - Google Patents

Abstract

To provide a semiconductor light-emitting device capable of suppressing an alteration reaction that may cause physical damage.SOLUTION: A semiconductor light-emitting device includes a semiconductor light-emitting element 10A that is formed with a semiconductor layer 12 including a light emitting layer 12b on a first surface of a nitride semiconductor substrate 11, and in which an electrode (first electrode) 13 is formed on a second surface of the nitride semiconductor substrate 11 opposite to the first surface, a submount 20 for mounting the semiconductor light-emitting element 10A, and a bonding layer 30 for bonding the electrode 13 to the submount 20. The entire second surface of the nitride semiconductor substrate 11 is separated from the bonding layer 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor light emitting device including a nitride semiconductor light emitting element.

2. Description of the Related Art Conventionally, there has been known a nitride semiconductor light emitting device in which a nitride semiconductor layer including a light emitting layer is formed on a first surface of a nitride semiconductor substrate such as GaN. In such a nitride semiconductor light emitting device, a first electrode is formed on a second surface of the nitride semiconductor substrate opposite to the first surface, and a second electrode is formed on the nitride semiconductor layer. Have been.
For example, Patent Document 1 discloses a GaN-based semiconductor laser using an n-type GaN substrate as a nitride semiconductor substrate. This GaN-based semiconductor laser has a semiconductor layer on an n-type GaN substrate, and has an n-type electrode on the back surface (the surface opposite to the semiconductor layer) of the n-type GaN substrate.

JP-A-2006-128558

As in the case of the nitride semiconductor light emitting device described in Patent Document 1, an exposed portion where no electrode is formed may be present on a part of the back surface of the nitride semiconductor substrate. When the nitride semiconductor light emitting device in which a part of the back surface of the nitride semiconductor substrate is exposed is bonded to the submount by a junction-up method, the exposed portion is formed by the submount and the nitride semiconductor light emitting device. It comes into contact with a bonding layer such as solder to be bonded. Then, due to long-term use of the nitride semiconductor light-emitting device, an alteration reaction may occur in a contact portion between the exposed portion of the nitride semiconductor substrate and the bonding layer.
The reactant generated at this time undergoes volume expansion at the time of formation, and may cause physical damage such as cracking or peeling of the electrode metal, the semiconductor layer, the bonding layer, or the like due to the stress resulting from the volume expansion.
Therefore, an object of the present invention is to provide a semiconductor light emitting device that can suppress a transformation reaction that may cause physical damage.

In order to solve the above problem, one embodiment of a semiconductor light emitting device according to the present invention includes forming a semiconductor layer including a light emitting layer on a first surface of a nitride semiconductor substrate, wherein the first surface of the nitride semiconductor substrate is provided. A semiconductor light emitting device having an electrode formed on a second surface opposite to the second surface, a submount for mounting the semiconductor light emitting device, and a bonding layer for bonding the electrode to the submount, The entire surface of the second surface of the nitride semiconductor substrate is separated from the bonding layer.
As described above, since the semiconductor light emitting device has a configuration in which the entire surface of the second surface of the nitride semiconductor substrate does not contact the bonding layer, there is a possibility that physical damage may occur at a contact portion between the nitride semiconductor substrate and the bonding layer. The occurrence of a certain alteration reaction can be suppressed.

In the above-described semiconductor light emitting device, the entire surface of the second surface of the nitride semiconductor substrate may not be exposed.
As described above, when the entire surface of the second surface of the nitride semiconductor substrate is covered with a member other than the bonding layer, the contact between the nitride semiconductor substrate and the bonding layer can be appropriately suppressed.

Further, in the above-described semiconductor light emitting device, the electrode is connected to a first electrode portion in contact with the second surface of the nitride semiconductor substrate, and the first electrode portion is connected to a side opposite to the second surface of the first electrode portion. A second electrode portion having a width smaller than that of the one electrode portion, wherein the second electrode portion is in contact with the bonding layer.
In this case, a physical distance can be provided between the nitride semiconductor substrate and the bonding layer, and contact between the nitride semiconductor substrate and the bonding layer can be avoided.

Further, in the above semiconductor light emitting device, the electrode is connected to a first electrode portion in contact with the second surface of the nitride semiconductor substrate, and the first electrode portion is connected to a side opposite to the second surface of the first electrode portion. A second electrode portion having a width smaller than that of the one electrode portion; and a barrier electrode formed on a surface of the second electrode portion opposite to the first electrode portion, wherein the barrier electrode is formed of the bonding layer. You may be in contact with.
In this case, the formation of the altered reactant in the contact portion with the bonding layer can be appropriately suppressed.

Furthermore, in the semiconductor light emitting device described above, the electrode may be formed on the entire second surface of the nitride semiconductor substrate.
As described above, by adopting a configuration in which the electrode covers the entire surface of the second surface of the nitride semiconductor substrate, contact between the nitride semiconductor substrate and the bonding layer can be easily and appropriately avoided.

In the above-described semiconductor light emitting device, the electrode is formed on a part of the second surface of the nitride semiconductor substrate, and an insulating layer is formed on a region of the second surface where the electrode is not formed. A layer may be further provided.
In this case, even when there is a region where no electrode is formed on the second surface of the nitride semiconductor substrate, the region can be covered with the insulating layer, and the contact between the nitride semiconductor substrate and the bonding layer can be reduced. Can be avoided appropriately.

Still further, in the above semiconductor light emitting device, the nitride semiconductor substrate has a first substrate portion on the semiconductor layer side and a second substrate portion located on the submount side and having a width smaller than the first substrate portion. And the electrode may be formed on the entire surface of the second substrate portion on the submount side.
In this case, even when a region where an electrode is not formed exists on the second surface of the nitride semiconductor substrate, a physical distance can be provided between the region and the bonding layer, and the nitride semiconductor The contact between the substrate and the bonding layer can be appropriately avoided.

In the above-described semiconductor light emitting device, the thickness of the electrode may be larger than the thickness of the bonding layer. In this case, the electrode is not buried in the bonding layer, and contact between the nitride semiconductor substrate and the bonding layer can be avoided.
Further, in the above semiconductor light emitting device, the width of the bonding layer may be wider than the width of the electrode. In this case, the nitride semiconductor light emitting device and the submount can be appropriately bonded while avoiding contact between the nitride semiconductor substrate and the bonding layer.
In the above-described semiconductor light emitting device, the width of the bonding layer may be equal to or smaller than the width of the electrode. In this case, contact between the nitride semiconductor substrate and the bonding layer can be appropriately avoided.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the structure which does not contact the whole surface of the 2nd surface of a nitride semiconductor substrate with a joining layer, and can suppress the transformation reaction which may cause physical damage.

1 is a cross-sectional view illustrating a configuration example of a semiconductor light emitting device according to a first embodiment. It is sectional drawing which shows the example of a structure of the semiconductor light emitting device in 2nd Embodiment. FIG. 11 is a cross-sectional view illustrating a configuration example of a semiconductor light emitting device according to a third embodiment. It is sectional drawing which shows the example of a structure of the semiconductor light-emitting device in 4th Embodiment. It is sectional drawing which shows the example of a structure of the semiconductor light-emitting device in 5th Embodiment. It is sectional drawing which shows the example of a structure of the semiconductor light emitting device in 6th Embodiment. It is sectional drawing which shows the example of a structure of the semiconductor light emitting device in 7th Embodiment. FIG. 11 is a cross-sectional view illustrating a configuration example of a conventional semiconductor light emitting device. FIG. 9 is a diagram illustrating a problem of a conventional semiconductor light emitting device. It is a figure showing the section at the time of long-term use of the semiconductor light emitting device of the comparative example. It is a figure showing the section at the time of long-term use of the semiconductor light emitting device of an example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view illustrating a configuration example of the semiconductor light emitting device according to the first embodiment.
The semiconductor light emitting device according to the present embodiment includes a semiconductor light emitting element 10A and a submount 20. In the present embodiment, the semiconductor light emitting device 10A is a semiconductor laser device that emits laser light when a predetermined injection current is supplied when the semiconductor light emitting device 10A is mounted on a semiconductor laser device that is a semiconductor light emitting device.

The semiconductor light emitting device 10A includes a nitride semiconductor substrate (hereinafter, simply referred to as “semiconductor substrate”) 11 having a first surface and a second surface. The semiconductor substrate 11 is made of, for example, a nitride semiconductor such as gallium nitride (GaN), aluminum nitride (AlN), or aluminum gallium nitride (AlGaN). In the present embodiment, a case where the semiconductor substrate 11 is a GaN substrate will be described.
On the first surface of the semiconductor substrate 11, a semiconductor layer 12 is formed. In the present embodiment, the first surface of the semiconductor substrate 11 is the upper surface in FIG. Further, the second surface of the semiconductor substrate 11 is a surface opposite to the first surface, that is, the lower surface in FIG.

The semiconductor layer 12 has a configuration in which at least a first conductive layer 12a, a light emitting layer (active layer) 12b, and a second conductive layer 12c are stacked in this order on a semiconductor substrate 11. The first conductive layer 12a is an n-type cladding layer (for example, n-AlGaN), and the second conductive layer is a p-type cladding layer (for example, p-AlGaN). The light emitting layer 12b has a quantum well structure made of, for example, GaInN.
The semiconductor light emitting element 10A includes an n-side electrode (first electrode) 13 formed on a second surface of the semiconductor substrate 11 (on a surface of the semiconductor substrate 11 opposite to the semiconductor layer 12), And a p-side electrode (second electrode) 14 formed on the insulating film 12 via an insulating film 16. The first electrode 13 is a multilayer electrode layer made of, for example, Ti / Al / Mo / Ti / Pt / Au, and the second electrode 14 is a multilayer electrode made of, for example, Pd / Ti / Pt / Au / Mo / Au. Layer.

Further, the semiconductor light emitting element 10A includes a light emitting unit 15 in the semiconductor layer 12. The light emitting section 15 corresponds to a specific area of the light emitting layer 12b.
Further, of the first conductive layer 12a and the second conductive layer 12c, a layer (the second conductive layer 12c in FIG. 1) located farther from the semiconductor substrate 11 than the light emitting layer 12b has a stripe shape. Ridge portion 17 is formed. The ridge portion 17 is a current narrowing portion for narrowing the current. The specific region is a region corresponding to the current constriction in the light emitting layer 12b.

The semiconductor light emitting device 10A is joined to the submount 20 via the joining layer 30. Here, the bonding layer 30 is a solder layer made of, for example, Au-Sn.
The main body of the submount 20 can be made of, for example, aluminum nitride (AlN). The main body of the submount 20 can be appropriately selected in consideration of heat dissipation, insulation, a difference in linear expansion coefficient from the semiconductor light emitting element 10A, cost, and the like.
An electrode wiring (not shown) is formed on the surface of the submount 20 with gold (Au), and the semiconductor light emitting element 10A is joined on the electrode wiring via a bonding layer 30 in a junction-up manner. That is, the surface of the first electrode 13 provided on the surface on the second surface side of the semiconductor substrate 11 of the semiconductor light emitting element 10A serves as a bonding surface and is bonded to the submount 20. Thereby, the first electrode 13 and the electrode wiring of the submount 20 are electrically connected.

In the present embodiment, the electrode width of the first electrode 13 is equal to the width of the semiconductor substrate 11, and the width of the bonding layer 30 is wider than the width of the first electrode 13 and the semiconductor substrate 11. Further, the width of the submount 20 is wider than the width of the bonding layer 30. Here, the width is the width in the left-right direction in FIG. 1 (the width in the direction orthogonal to the cavity direction). For example, the width of the first electrode 13 and the semiconductor substrate 11 can be 200 μm, the width of the bonding layer 30 can be 400 μm, and the width of the submount 20 can be 800 μm.
In the present embodiment, the thickness (total thickness) of the first electrode 13 is smaller than the thickness of the bonding layer 30. For example, the thickness (total thickness) of the first electrode 13 can be 500 nm, and the thickness of the bonding layer 30 can be 2 μm to 3 μm.

As described above, in the semiconductor light emitting device 10A of the present embodiment, the first electrode 13 is formed on the entire surface of the second surface of the semiconductor substrate 11, and the entire surface of the second surface of the semiconductor substrate 11 is bonded to the bonding layer. 30, that is, separated from the bonding layer 30. That is, the semiconductor substrate 11 is not in contact with the bonding layer 30.
FIG. 8 is a cross-sectional view illustrating a configuration example of a semiconductor light emitting device using a semiconductor light emitting element 110 as a comparative example. In FIG. 8, portions having the same configuration as that of the semiconductor light emitting element 10A are denoted by the same reference numerals as those in FIG. 1, and the following description will focus on portions different in configuration from FIG.
The semiconductor light emitting device 110 includes a first electrode 113 that is narrower than the semiconductor substrate 11. Therefore, there is an exposed portion 111 where the first electrode 113 is not formed on the outer peripheral portion of the second surface of the semiconductor substrate 11, and the exposed portion 111 comes into contact with the bonding layer 30. Note that the first electrode 113 can be made of the same material as the first electrode 13 in FIG.

The exposed portion 111 of the semiconductor substrate 11 is used, for example, for shape recognition of the semiconductor light emitting device 110.
The semiconductor light emitting device is formed by cutting one wafer. At this time, it is necessary to recognize the shape of the semiconductor light-emitting element and to cut the wafer at the cutting position to cleave the wafer. Therefore, in order to recognize the shape of the semiconductor light emitting element, the electrode on the second surface side of the semiconductor substrate may be formed to correspond to the shape of the semiconductor light emitting element after cutting. In this case, in the semiconductor light emitting element after cutting, an electrode having a width smaller than that of the semiconductor substrate is formed on the second surface.

  However, when such a semiconductor light emitting device 110 is bonded to the submount 20 by a junction-up method via the bonding layer 30, a contact portion between the exposed portion 111 of the semiconductor substrate 11 and the bonding layer 30 during a long-term operation. An alteration reaction occurs. Then, as shown in FIG. 9, a layered alteration reaction section 131 is formed at the contact portion. The altered reaction section 131 applies a force in the direction toward the inside of the semiconductor light emitting element 110 due to volume expansion in the forming process, and the force may damage the semiconductor light emitting device. For example, cracks 132 occur in the bonding layer 30 due to the stress. There is a possibility that the bonding layer 30 may be peeled off or the semiconductor light emitting device 110 may come off the submount 20. In addition, there is a possibility that the electrode metal may be peeled off or the semiconductor substrate 11 may be cracked.

On the other hand, the semiconductor light emitting device 10 </ b> A according to the present embodiment has a configuration in which the entire second surface of the semiconductor substrate 11 is separated from the bonding layer 30. Specifically, the first electrode 13 is formed on the entire surface of the second surface of the semiconductor substrate 11, and the entire surface of the second surface of the semiconductor substrate 11 is not exposed. Thus, the second surface of the semiconductor substrate 11 is not in contact with the bonding layer 30. Therefore, contact between the semiconductor substrate 11 and the bonding layer 30 can be avoided, and generation of the altered reaction section 131 as shown in FIG. 9 can be suppressed. As a result, occurrence of physical damage of the semiconductor light emitting device can be suppressed.
In the semiconductor light emitting device of the present embodiment, the bonding layer 30 is formed to extend outward from the edge of the first electrode 13. Thus, the width of the bonding layer 30 can be wider than the width of the first electrode 13. In the present embodiment, the semiconductor light emitting device 10A can be appropriately bonded to the submount 20 while avoiding the contact between the semiconductor substrate 11 and the bonding layer 30 to suppress the above-described alteration reaction.

(Second embodiment)
Next, a second embodiment of the present invention will be described.
FIG. 2 is a cross-sectional view illustrating a configuration example of the semiconductor light emitting device according to the second embodiment.
The semiconductor light emitting device according to the present embodiment includes a semiconductor light emitting element 10B and a submount 20. The semiconductor light emitting device 10B has a configuration in which the first electrode 13 of the semiconductor light emitting device 10A in the above-described first embodiment is raised.

Specifically, the semiconductor light emitting element 10B is connected to a surface of the first electrode 13 opposite to the second surface of the semiconductor substrate 11, and includes a third electrode 13a having a smaller electrode width than the first electrode 13. Further prepare. Then, the semiconductor light emitting element 10B is joined to the submount 20 via the joining layer 30 with the surface of the third electrode 13a serving as a joining surface.
The third electrode 13a can be formed by, for example, Au plating.

  Here, the thickness of the third electrode 13a can be larger than the thickness of the bonding layer 30. When the thickness of the bonding layer 30 is 2 μm to 3 μm, the thickness of the third electrode 13 a may be 5 μm or less (however, at least exceeds 3 μm). Further, for example, the width of the first electrode 13 and the semiconductor substrate 11 can be 200 μm, the width of the third electrode 13a can be 140 μm, the width of the bonding layer 30 can be 400 μm, and the width of the submount 20 can be 800 μm.

Note that the first electrode 13 and the third electrode 13a may be integrally formed. That is, the electrode formed on the second surface of the semiconductor substrate 11 is connected to the first electrode portion that is in contact with the entire surface of the second surface, and is connected to the first electrode portion on the side opposite to the second surface. A second electrode portion having a width smaller than the portion may be provided, and the second electrode portion may be in contact with the bonding layer 30.
Further, in the present embodiment, the case where the first electrode 13 is formed on the entire second surface of the semiconductor substrate 11 has been described, but the first electrode 13 is formed on the second surface of the semiconductor substrate 11. It may be formed in a part. That is, the first electrode portion may be configured to be in contact with a part of the second surface of the semiconductor substrate 11.

As described above, the semiconductor light emitting device 10 </ b> B according to the present embodiment is configured such that the first electrode 13 in contact with the second surface of the semiconductor substrate 11 is connected to the opposite side of the second surface of the first electrode 13, And a third electrode 13a having a width smaller than that of the third electrode 13. The third electrode 13a is bonded to the bonding layer 30.
As described above, by raising the first electrode 13 on the second surface of the semiconductor substrate 11, the semiconductor substrate 11 and the bonding layer 30 can be arranged at a physical distance. At this time, by making the thickness of the third electrode 13a thicker than the thickness of the bonding layer 30, when the semiconductor light emitting device 10B is bonded to the submount 20, the third electrode 13a is formed on the bonding layer 30. It is possible to prevent the semiconductor substrate 11 from being in contact with the bonding layer 30 without being buried. Therefore, contact between the semiconductor substrate 11 and the bonding layer 30 can be reliably avoided.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
FIG. 3 is a cross-sectional view illustrating a configuration example of a semiconductor light emitting device according to the third embodiment.
The semiconductor light emitting device according to the present embodiment includes a semiconductor light emitting element 10C and a submount 20. The semiconductor light emitting device 10C has a configuration in which a barrier electrode 13b is added to the semiconductor light emitting device 10B in the second embodiment described above.

  Specifically, a barrier electrode 13b is formed on a surface of the third electrode 13a opposite to the first electrode 13. The barrier electrode 13b is made of a material that does not react with the bonding layer 30. For example, the barrier electrode 13b can be a multilayer electrode layer made of Ti / Pt / Au. Here, the electrode width of the barrier electrode 13b is equal to the electrode width of the third electrode 13a. The thickness (total thickness) of the barrier electrode 13b can be, for example, 500 nm. The width and thickness of the other members may be the same as in the above-described second embodiment.

As described above, the semiconductor light emitting device 10 </ b> C according to the present embodiment is connected to the first electrode 13 in contact with the second surface of the semiconductor substrate 11 and on the opposite side to the second surface of the first electrode 13. And a barrier electrode 13b formed on the surface of the third electrode 13a opposite to the first electrode 13. The semiconductor light emitting device 10C has a configuration in which the barrier electrode 13b is bonded to the bonding layer 30.
As described above, by raising the electrodes on the second surface of the semiconductor substrate 11, the semiconductor substrate 11 and the bonding layer 30 are arranged at a physical distance from each other, as in the second embodiment. Therefore, contact between the semiconductor substrate 11 and the bonding layer 30 can be avoided. Further, in the semiconductor light emitting device 10C, since the barrier electrode 13b is bonded to the bonding layer 30, the penetration of the bonding layer 30 into the electrode can be prevented.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
FIG. 4 is a cross-sectional view illustrating a configuration example of a semiconductor light emitting device according to the fourth embodiment.
The semiconductor light emitting device according to the present embodiment includes a semiconductor light emitting element 10D and a submount 20. In the semiconductor light emitting device 10D, the electrode width of the first electrode 13 of the semiconductor light emitting device 10A in the above-described first embodiment is smaller than the width of the semiconductor substrate 11, and the second surface of the semiconductor substrate 11 and the bonding layer 30 Has a configuration in which an insulating layer (insulating film) 18 is arranged in a space facing the same.

Specifically, the first electrode 13 is formed on a part of the second surface of the semiconductor substrate 11, and the second surface of the semiconductor substrate 11 is provided with an electrode that is not provided with the first electrode 13. There is a formation area. Then, an insulating layer 18 is formed in the non-electrode formation region. The insulating layer 18 can be made of a material that does not react with the bonding layer 30. Here, the electrode width of the first electrode 13 is smaller than the width of the semiconductor substrate 11, and the first electrode 13 and the insulating layer 18 Is equal to the width of the semiconductor substrate 11. Further, the thickness of the insulating layer 18 is equal to the thickness of the first electrode 13. The width and thickness of the other members may be the same as in the first embodiment described above.

  As described above, the semiconductor light emitting device 10D according to the present embodiment includes the insulating layer 18 disposed in a space where the second surface of the semiconductor substrate 11 and the bonding layer 30 face each other. Thus, the insulating layer 18 protects the exposed portion of the semiconductor substrate 11 and avoids contact between the semiconductor substrate 11 and the bonding layer 30.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described.
FIG. 5 is a cross-sectional view illustrating a configuration example of a semiconductor light emitting device according to the fifth embodiment.
The semiconductor light emitting device according to the present embodiment includes a semiconductor light emitting element 10E and a submount 20. The semiconductor light emitting element 10E has a configuration in which a cut portion 11a is provided on the semiconductor substrate 11, and the electrode width of the first electrode 13 is smaller than the width of the semiconductor substrate 11.

Specifically, the semiconductor substrate 11 has a first substrate portion on the semiconductor layer 12 side and a second substrate portion on the submount 20 side, and the second substrate portion is narrower than the first substrate portion. Has become. Then, the first electrode 13 is formed on the entire surface of the second substrate portion of the semiconductor substrate 11 on the submount 20 side, and the first electrode 13 and the bonding layer 30 are in contact with each other.
In the semiconductor substrate 11 shown in FIG. 5, a second surface opposite to the first surface has an exposed surface 11b facing the bonding layer 30 in the first substrate portion, and a first electrode 13 in the second substrate portion. And the surface being formed. That is, on the second surface of the semiconductor substrate 11, a space is formed between the non-electrode formation region (exposed surface 11 b) where the first electrode 13 is not formed and the bonding layer 30.

As described above, the semiconductor substrate 11 of the semiconductor light emitting device 10E in the present embodiment is located on the first substrate portion on the semiconductor layer 12 side and on the submount 20 side, and has a second width smaller than the first substrate portion. A substrate portion. The semiconductor light emitting element 10E has a configuration in which the first electrode 13 is formed on the entire surface of the second substrate portion of the semiconductor substrate 11 on the submount 20 side.
Thus, by cutting the semiconductor substrate 11, a physical distance between the exposed portion of the semiconductor substrate 11 and the bonding layer 30 can be secured. Therefore, contact between the semiconductor substrate 11 and the bonding layer 30 can be avoided.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described.
FIG. 6 is a cross-sectional view illustrating a configuration example of a semiconductor light emitting device according to the sixth embodiment.
The semiconductor light emitting device according to the present embodiment includes a semiconductor light emitting element 10F and a submount 20. In the semiconductor light emitting device 10F, the electrode width of the first electrode 13 of the semiconductor light emitting device 10A in the above-described first embodiment is smaller than the width of the semiconductor substrate 11, and the width of the bonding layer 30 is smaller than that of the first electrode 13. It has a configuration that is smaller than the electrode width.

Specifically, the first electrode 13 is formed on a part of the second surface of the semiconductor substrate 11, and the second surface of the semiconductor substrate 11 is provided with an electrode that is not provided with the first electrode 13. There is a formation region 11c. A space is formed between the electrode non-formation region 11c and the submount 20. That is, the electrode non-formation region 11 c faces the submount 20 and does not face the bonding layer 30.
Although FIG. 6 shows an example in which the electrode width of the first electrode 13 is equal to the width of the bonding layer 30, the width of the bonding layer 20 may be smaller than the electrode width of the first electrode 13. Good.

  Further, in the present embodiment, the case where the width of the bonding layer 30 is set to be equal to or less than the electrode width of the first electrode 13 has been described, but the width of the bonding layer 30 is equal to the electrode width of the electrode bonded to the bonding layer 30. The following may be sufficient. For example, in the case of the semiconductor light emitting device 10B shown in FIG. 2, the width of the bonding layer 30 may be smaller than the electrode width of the third electrode 13a. Further, in the case of the semiconductor light emitting device 10C shown in FIG. 3, the width of the bonding layer 30 may be smaller than the electrode width of the barrier electrode 13b.

  As described above, in the semiconductor light emitting device according to the present embodiment, the width of the bonding layer 30 can be equal to or smaller than the width of the electrode formed on the second surface of the semiconductor substrate 11. As described above, by reducing the application area of the bonding layer 30, even when an exposed portion exists on the second surface of the semiconductor substrate 11, it is possible to avoid contact between the semiconductor substrate 11 and the bonding layer 30. it can.

(Seventh embodiment)
Next, a seventh embodiment of the present invention will be described.
FIG. 7 is a cross-sectional view illustrating a configuration example of a semiconductor light emitting device according to the seventh embodiment.
The semiconductor light emitting device according to the present embodiment includes a semiconductor light emitting element 10G and a submount 20. In the semiconductor light emitting device 10G, the electrode width of the first electrode 13 of the semiconductor light emitting device 10A in the above-described first embodiment is smaller than the width of the semiconductor substrate 11, and the thickness of the first electrode 13 is set to the bonding layer 30. The thickness is larger than the thickness.

  Specifically, the first electrode 13 is formed on a part of the second surface of the semiconductor substrate 11, and the second surface of the semiconductor substrate 11 is provided with an electrode that is not provided with the first electrode 13. There is a formation region 11c. A space is formed between the electrode non-formation region 11c and the bonding layer 30.

As described above, the thickness of the first electrode 13 of the semiconductor light emitting device 10G in the present embodiment is larger than the thickness of the bonding layer 30. As described above, by increasing the thickness of the first electrode 13 and increasing the thickness, the semiconductor substrate 11 and the bonding layer 30 can be arranged at a physically large distance. Therefore, even when there is an exposed portion on the second surface of the semiconductor substrate 11, contact between the semiconductor substrate 11 and the bonding layer 30 can be reliably avoided.
In the present embodiment, the case where the electrode non-formation region 11c exists on the second surface of the semiconductor substrate 11 has been described. However, when the electrode non-formation region 11c does not exist on the second surface of the semiconductor substrate 11, the semiconductor The thickness of the electrode formed on the second surface of the substrate 11 may be set to be larger than the thickness of the bonding layer 30.

(Example)
Next, examples performed to confirm the effects of the present invention will be described.
In the semiconductor light emitting device using the semiconductor light emitting device 110 shown in FIG. 8 as a comparative example, and the semiconductor light emitting device using the semiconductor light emitting device 10C shown in FIG. It was confirmed.
FIG. 10 is a diagram showing a cross section of the semiconductor light emitting device using the semiconductor light emitting device 110 shown in FIG. 8 during long-term use. FIG. 11 is a diagram showing the semiconductor light emitting device using the semiconductor light emitting device 10C shown in FIG. FIG. As a result of performing an acceleration test on each semiconductor light emitting device and enlarging a cross section of each semiconductor light emitting device with a scanning electron microscope (SEM), as shown in FIG. It was confirmed that an alteration reaction section 131 was formed at the contact portion with. On the other hand, as shown in FIG. 11, in the semiconductor light emitting device 10C, the altered reaction section as shown in FIG. 10 could not be confirmed.
That is, in the above example, it was confirmed that the alteration reaction that might cause physical damage can be suppressed, and long-term reliability can be obtained.

  10A to 10G: semiconductor light emitting element, 11: nitride semiconductor substrate, 11a: cut portion, 12: semiconductor layer, 13: n-side electrode (first electrode), 13a: third electrode, 13b: barrier electrode, 14 p-side electrode (second electrode), 15 light emitting portion, 16 insulating film, 17 ridge portion, 18 insulating layer, 20 submount, 30 bonding layer

Claims (10)

A semiconductor light emitting device comprising: a semiconductor layer including a light emitting layer formed on a first surface of a nitride semiconductor substrate; and an electrode formed on a second surface of the nitride semiconductor substrate opposite to the first surface. ,
A submount for mounting the semiconductor light emitting element,
A bonding layer for bonding the electrode to the submount,
A semiconductor light emitting device, wherein the entire surface of the second surface of the nitride semiconductor substrate is separated from the bonding layer.   2. The semiconductor light emitting device according to claim 1, wherein the entire surface of the second surface of the nitride semiconductor substrate is not exposed. The electrode is
A first electrode portion in contact with the second surface of the nitride semiconductor substrate;
A second electrode portion connected to a side of the first electrode portion opposite to the second surface and having a smaller width than the first electrode portion;
The semiconductor light emitting device according to claim 1, wherein the second electrode portion is in contact with the bonding layer. The electrode is
A first electrode portion in contact with the second surface of the nitride semiconductor substrate;
A second electrode portion connected to a side of the first electrode portion opposite to the second surface and having a width smaller than that of the first electrode portion;
A barrier electrode formed on a surface of the second electrode portion opposite to the first electrode portion;
The device according to claim 1, wherein the barrier electrode is in contact with the bonding layer.   The semiconductor light emitting device according to claim 1, wherein the electrode is formed on an entire surface of the second surface of the nitride semiconductor substrate. The electrode is formed on a part of the second surface of the nitride semiconductor substrate,
The semiconductor light emitting device according to claim 1, further comprising an insulating layer formed in a region of the second surface where the electrode is not formed. The nitride semiconductor substrate,
A first substrate portion on the semiconductor layer side;
A second substrate portion located on the submount side and having a width smaller than the first substrate portion;
2. The semiconductor light emitting device according to claim 1, wherein the electrode is formed on an entire surface of the second substrate portion on the submount side. 3.   The device according to claim 1, wherein a thickness of the electrode is greater than a thickness of the bonding layer.   9. The semiconductor light emitting device according to claim 1, wherein a width of the bonding layer is wider than a width of the electrode. 10.   The semiconductor light emitting device according to claim 1, wherein a width of the bonding layer is equal to or less than a width of the electrode.

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