JP2017092403A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emission device that is able to hold joining of a base and a light-emitting element in which an electrode is formed.SOLUTION: A light-emitting device comprises: a light-emitting element having a p-layer and n-layer formed from an indirect transition type semiconductor; a first electrode joined to one face of the light-emitting element in a thickness direction and a second electrode joined to the other face thereof; a cushioning member disposed on the face of the first electrode which face is opposite the light-emitting element; a base disposed on the face of the second electrode which face is opposite the light-emitting element; a first joining member provided between the first electrode and a cushioning material and joining them; and a second member provided between the second electrode and the base and joining them. The first joining member is higher in fusion point than the heating temperature of the light-emitting element after the application of voltage. The cushioning member is higher in rigidity than the light-emitting element. The second joining member is lower in fusion point than the heating temperature of the light-emitting element after the application of voltage, and changes from a solid to an adhesive fluid by its being heated by the heat of the light-emitting element transmitted via the second electrode.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device applied to an indirect transition type semiconductor laser device.

  As a light emitting element of an indirect semiconductor laser that obtains laser transmission by current injection, there is one described in Patent Document 1. The light emitting element is formed at a junction between a p layer in which an p-type impurity is added to an indirect semiconductor such as silicon, an n layer in which an n-type impurity is added to the indirect semiconductor, and a p layer and an n layer. A pn junction layer corresponding to a so-called active layer.

  The p layer and the n layer are light emitting portions that emit light when electrons are applied to all of the regions of the p layer and the n layer. A power source is connected to the n layer and the p layer, and a bias voltage is applied in the forward direction so that the n layer side is a positive voltage and the p layer side is a negative voltage when the laser is transmitted. As a result, current is injected into the n layer, the pn junction layer, and the n layer, and electrons are applied to the light emitting portions in the n layer, the pn junction layer, and the n layer, so that part or all of the light is emitted.

JP 2012-243824 A

  Here, at the time of laser emission, a bias voltage is applied between the p-type electrode and the n-type electrode in the above-described light-emitting element with the p-type electrode formed on the p-layer surface and the n-type electrode formed on the n-layer surface. The

  By the way, the thermal expansion coefficient differs between the p-type electrode and the n-type electrode and the light emitting element. Therefore, the light-emitting element on which the p-type electrode and the n-type electrode are formed is warped due to heat generation when a voltage is applied. Further, when viewed from the thickness direction, the light emitting element is designed so that the length in the length direction, which is the resonance direction of light, is larger than the length in the width direction. More specifically, for example, the width of the light emitting element is about 100 nm, while the length is 100 mm. That is, the length of the light emitting element is about 1000 times its width. Therefore, even if the thermal change is small, both end portions in the length direction of the light emitting element are greatly warped with respect to the central portion.

  In addition, a base (corresponding to a heat sink) for suppressing heat generation when a voltage is applied is joined to the surface of the light emitting element. However, when the above-described warpage occurs in the light-emitting element, a part of the bonding between the electrode on the surface of the light-emitting element and the base is released or the base is completely separated from the electrode by the force applied during the deformation. There is a risk that. When such a problem occurs, heat dissipation from the base becomes insufficient, which causes a problem such as breakage of the light emitting element.

  This invention is made | formed in view of the said situation, The objective is to provide the light emitting device which can hold | maintain joining of the light emitting element in which the electrode was formed, and a base.

  The light-emitting device according to the first aspect of the present invention includes a p-layer made of an indirect transition semiconductor doped with a p-type impurity, an n-layer made of an indirect transition-type semiconductor doped with an n-type impurity, the p layer and the n layer A pn junction layer formed at a junction between the p layer, the pn junction layer, and the n by injecting electrons when a voltage is applied and applying electrons. A light-emitting element that emits light from a part or all of the layer, a first electrode formed on one surface in the thickness direction of the light-emitting element, and a surface on the other surface in the thickness direction of the light-emitting element A second electrode; a buffer member disposed on a surface of the first electrode opposite to the light emitting element; a base disposed on a surface of the second electrode opposite to the light emitting element; and the first electrode. And a first contact that joins them together. A second bonding member that is provided between the second electrode and the base and bonds the two, and the first bonding member has a melting point that is a heating temperature of the light emitting element after voltage application The buffer member is higher in rigidity than the light emitting element, and the second bonding member has a melting point lower than the heat generation temperature of the light emitting element after voltage application, and is transmitted through the second electrode. By being heated by the heat of the light emitting element, the solid is changed into a viscous fluid.

  In the present invention, the melting point of the first bonding member is higher than the heat generation temperature of the light emitting element after voltage application. Therefore, the first bonding member is not melted by the heat from the light emitting element after voltage application. Thereby, it is possible to continue to fix the buffer member without relative movement with respect to the light emitting element. The buffer member has higher rigidity than the light emitting element. Therefore, since the buffer member integrated with the light emitting element can suppress the warpage of the light emitting element caused by the difference in thermal expansion coefficient from the electrode, it is possible to prevent the bonding between the light emitting element and the base from being released. Further, the melting point of the second bonding member is lower than the heat generation temperature of the light emitting element after the voltage is applied, and the second bonding member is melted by being heated by the heat of the light emitting element transmitted through the second electrode, so that the viscosity of the second bonding member is reduced. It changes into the fluid which has. Therefore, even when the light emitting element is warped, the second joining member that has become a fluid continues to be integrated so as to follow the shape change of the light emitting element. Thereby, it can prevent reliably that joining of a light emitting element and a base is cancelled | released.

  In the light emitting device according to a second aspect of the present invention, in the first aspect, the buffer member has a thermal conductivity greater than or equal to the base.

  In the present invention, the buffer member has a thermal conductivity larger than that of the base. Therefore, the heat generated in the light emitting element due to the voltage application can be actively dissipated from the buffer member side opposite to the base. Thereby, compared with the case where the heat which generate | occur | produced in the light emitting element is thermally radiated only from a base, it can thermally radiate more efficiently.

  A light emitting device of a third invention is the light emitting device according to the first or second invention, wherein the second joining member disposed between the second electrode and the base is between the first electrode and the buffer material. It is characterized in that the thickness is larger than that of the first joining member disposed on the surface.

  In the present invention, the second bonding member disposed between the second electrode and the base is thicker than the first bonding member disposed between the first electrode and the buffer material. Therefore, the distance between the second electrode and the base is large, that is, the play that the light emitting element can move is large. Thereby, for example, the second bonding member can follow the warp of the light-emitting element even in a place where a large warp occurs compared to the central part, such as both ends in the longitudinal direction of the light-emitting element. The junction between the light emitting element and the base can be reliably held. Thereby, it can prevent more reliably that joining of a light emitting element and a base is cancelled | released.

  The light-emitting device according to a fourth aspect is the light-emitting device according to any one of the first to third aspects, wherein the first electrode is disposed on one entire surface of the light-emitting element, and the first joint portion is the first electrode. The buffer member is bonded so as to cover the entire surface of the first electrode.

  In the present invention, the first electrode is disposed on one whole surface of the light emitting element, the first bonding member for bonding the first electrode and the buffer member is provided on the entire surface of the first electrode, and the buffer member is the first electrode. It is joined so as to cover the entire surface. Therefore, the indirect contact area between the light emitting element that generates heat and the buffer member that dissipates heat can be maximized. Thereby, since heat can be radiated from the entire surface of the light emitting element, heat can be radiated more efficiently than in the case where heat is radiated from a part of the surface of the light emitting element.

  The light-emitting device according to a fifth invention is the light-emitting device according to any one of the first to fourth inventions, wherein the second electrode is disposed on the entire other surface of the light-emitting element, and the second bonding member is the second electrode. The base is bonded so as to cover the entire surface of the second electrode.

  In the present invention, the second electrode is disposed on the entire other surface of the light emitting element, the second bonding member for bonding the second electrode and the base is provided on the entire surface of the second electrode, and the base covers the entire surface of the second electrode. Joined to cover. Therefore, the indirect contact area between the light emitting element that generates heat and the base that dissipates heat can be maximized. Thereby, since heat can be radiated from the entire surface of the light emitting element, heat can be radiated more efficiently than in the case where heat is radiated from a part of the surface of the light emitting element.

  A light-emitting device according to a sixth invention is the light-emitting device according to any one of the first to fifth inventions, wherein the base is disposed on the p-layer side of the light-emitting element, and the buffer material is on the n-layer side of the light-emitting element. It is characterized by being arranged.

  In the present invention, the base is disposed on the p-layer side of the light-emitting element, and the buffer material is disposed on the n-layer side of the light-emitting element. Therefore, the second bonding member can be actively dissolved by disposing the base on the p-layer side that generates a large amount of heat. Thereby, the junction between the p-type electrode and the base can be reliably held. In addition, heat generated in the light emitting element can be radiated more efficiently from the base side having a large heat radiation capability.

It is a perspective view of the light-emitting device concerning this embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  This embodiment is an example in which the present invention is applied to a light emitting device that is applied to a semiconductor laser device and emits light by applying a bias voltage in the forward direction so that the n layer side has a positive voltage and the p layer side has a negative voltage. It is. In the following description, the up / down, left / right, and front / rear directions shown in FIG. 1 are defined as the up / down direction, left / right direction, and front / rear direction, and these direction words are used as appropriate.

  As shown in FIG. 1, the light emitting device 100 has a substantially rectangular parallelepiped shape having a length in the front-rear direction that is larger than a length in the left-right direction. More specifically, the length of the light emitting device 100 in the left-right direction is 100 nm, the length in the front-rear direction is 100 mm, and the length in the front-rear direction is 1000 times the length in the left-right direction. . The light emitting device 100 includes a light emitting element 10, an n-type electrode 4, a p-type electrode 5, a buffer member 6, and a heat sink 7. The light emitting element 10, the n-type electrode 4, the p-type electrode 5, the buffer member 6, and the heat sink 7 become the buffer member 6, the n-type electrode 4, the light-emitting element 10, the p-type electrode 5, and the heat sink 7 in order from the top. Has been placed.

  The light-emitting element 10 includes a p-layer 2 in which a p-type impurity is added to an indirect semiconductor such as silicon, an n-layer 1 in which an n-type impurity is added to an indirect semiconductor, and a junction between the p-layer 2 and the n-layer 1. The pn junction layer 3 is formed. Part of the p layer 2 and the n layer 1 is a light emitting portion that emits light when a voltage is applied to apply electrons. All the regions of the pn junction layer 3 are light emitting portions.

  The n-type electrode 4 is disposed on the upper surface of the n layer 1. The n-type electrode 4 has substantially the same length in the left-right and front-rear directions as the n-layer 1 and is disposed so as to cover the entire surface of the n-layer 1. The p-type electrode 5 is disposed on the lower surface of the p layer 2. The p-type electrode 5 has substantially the same length in the left-right and front-back directions as the p-layer 2 and is disposed so as to cover the entire surface of the p-layer 2.

  The buffer member 6 is disposed on the upper surface side of the n-type electrode 4. The buffer member 6 has a rectangular parallelepiped shape having a predetermined thickness, is substantially equal in length to the left and right and in the front-rear direction, and is disposed so as to cover the entire surface of the n-type electrode 4. The buffer member 6 has higher rigidity than the light emitting element 10. The buffer member 6 has a thermal conductivity larger than that of the heat sink 7 described later. The buffer member 6 is made of, for example, aluminum nitride.

  The heat sink 7 is disposed on the lower surface side of the p-type electrode 5. The heat sink 7 has a substantially rectangular parallelepiped shape having a predetermined thickness, is substantially equal in length in the left-right and front-rear directions, and is disposed so as to cover the entire surface of the p-type electrode 5.

  Further, the n-type electrode 4 and the buffer member 6 are joined by a first solder 8 provided on the entire surface of the n-type electrode 4. The melting point of the first solder 8 is higher than the heat generation temperature of the light emitting element 10 after voltage application. The p-type electrode 5 and the heat sink 7 are joined by a second solder 9 provided on the entire surface of the p-type electrode 5. The second solder 9 has a melting point lower than the heat generation temperature of the light-emitting element 10 after voltage application, and is heated by heat from the light-emitting element 10 transmitted through the p-type electrode 5, whereby the second solder 9 becomes viscous from a solid. Into a fluid having Further, the thickness d2 of the second solder 9 is provided to be larger than the thickness d1 of the first solder 8.

(Function and effect)
In the present embodiment, the melting point of the first solder 8 is higher than the heat generation temperature of the light emitting element 10 after voltage application. Therefore, the first solder 8 is not melted by the heat from the light emitting element 10 after voltage application. As a result, the buffer member 6 can be continuously fixed to the light emitting element 10 without relative movement. The buffer member 6 has higher rigidity than the light emitting element 10. Therefore, since the buffer member 6 integrated with the light emitting element 10 can suppress warping of the light emitting element 10 caused by the difference in thermal expansion coefficient between the n-type electrode 4 and the p-type electrode 5 and the light emitting element 10, It is possible to prevent the bonding between the element 10 and the heat sink 7 from being released. Furthermore, the second solder 9 has a melting point lower than the heat generation temperature of the light emitting element 10 after voltage application, and is melted by being heated by the heat of the light emitting element 10 transmitted through the p-type electrode 5. It changes from a solid to a viscous fluid. Therefore, even when the light emitting element 10 is warped, the second solder 9 that has become a fluid continues to be integrated so as to follow the shape change of the light emitting element 10. Thereby, it can prevent reliably that joining of the light emitting element 10 and the heat sink 7 is cancelled | released.

  Further, the buffer member 6 has a thermal conductivity larger than that of the heat sink 7. Therefore, heat generated in the light emitting element 10 due to voltage application can be actively dissipated not only from the heat sink 7 side but also from the buffer member 6 side. Thereby, compared with the case where the heat which generate | occur | produced in the light emitting element 10 is thermally radiated only from the heat sink 7, it can thermally radiate more efficiently.

  The thickness d2 of the second solder 9 is larger than the thickness d1 of the first solder 8. Therefore, the distance between the p-type electrode 5 and the heat sink 7 is large, that is, the play in which the light emitting element 10 can move in the vertical direction is large. Thereby, for example, the second solder 9 can follow the warp of the light emitting element 10 even in a place where a large warp occurs compared to the central part, such as both ends in the front-rear direction of the light emitting element 10. Therefore, the bonding between the light emitting element 10 and the heat sink 7 can be reliably held. Thereby, it can prevent more reliably that joining of the light emitting element 10 and the heat sink 7 is cancelled | released.

  The n-type electrode 4 is disposed on the entire surface of the n-layer 1, and the first solder 8 that joins the n-type electrode 4 and the buffer member 6 is provided on the entire surface of the n-type electrode 4. The mold electrode 4 is joined so as to cover the entire surface. Therefore, the indirect contact area between the light emitting element 10 that generates heat and the buffer member 6 that dissipates heat can be maximized. Thereby, since heat can be radiated from the entire surface of the light emitting element 10, heat can be radiated more efficiently than in the case where heat is radiated from a part of the surface of the light emitting element 10.

  The p-type electrode 5 is disposed on the entire surface of the p-layer 2, and the second solder 9 that joins the p-type electrode 5 and the heat sink 7 is provided on the entire surface of the p-type electrode 5. It is joined so as to cover the entire surface of 5. Therefore, the indirect contact area between the light emitting element 10 that generates heat and the heat sink 7 that dissipates heat can be maximized. Thereby, since heat can be radiated from the entire surface of the light emitting element 10, heat can be radiated more efficiently than in the case where heat is radiated from a part of the surface of the light emitting element 10.

  The heat sink 7 is disposed on the p-layer 2 side of the light-emitting element 10, and the buffer member 6 is disposed on the n-layer 1 side of the light-emitting element 10. Therefore, the second solder 9 can be actively dissolved by disposing the heat sink 7 on the side of the p layer 2 that generates a large amount of heat. Thereby, the joining of the p-type electrode 5 and the heat sink 7 can be reliably held. Further, the heat generated in the light emitting element 10 can be radiated more efficiently from the heat sink 7 side having a large heat radiation capability.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments and examples, and various design changes can be made as long as they are described in the claims. is there.

  In the present embodiment, the n-type electrode 4 is described as being disposed on the entire surface of the n layer 1, but the n-type electrode 4 may be disposed only on a part of the surface of the n layer 1.

  Although the buffer member 6 is described as being disposed on the entire upper surface of the n-type electrode 4, the buffer member 6 has a rigidity capable of suppressing the warp of the light emitting element 10, and the n-type electrode 4. It does not need to be arranged on the entire upper surface. More specifically, the buffer member 6 may be smaller in length in the left-right direction than the n-type electrode 4, for example.

  Although the p-type electrode 5 is described as being disposed on the entire surface of the p layer 2, the p-type electrode 5 may be disposed only on a part of the surface of the p layer 2.

  Although the heat sink 7 is described as being disposed on the entire lower surface of the p-type electrode 5, the heat sink 7 may be disposed only on a part of the surface of the p-type electrode 5.

  In addition, the thickness d2 of the second solder 9 is described as being greater than the thickness d1 of the first solder 8. However, for example, if the heat generation of the light emitting element 10 is small and the warp generated in the light emitting element 10 is small. The thickness of the second solder 9 may be approximately the same as the thickness of the first solder 8.

  In addition, it is described that the buffer member 6 is disposed above the n-type electrode 4 and the heat sink 7 is disposed below the p-type electrode 5, but the heat sink 7 and the lower side of the p-type electrode 5 are disposed above the n-type electrode 4. The shock-absorbing member 6 may be disposed on the surface.

DESCRIPTION OF SYMBOLS 1 n layer 2 p layer 3 pn junction layer 4 n-type electrode 5 p-type electrode 6 Buffer member 7 Heat sink 8 First solder 9 Second solder 10 Light emitting element 100 Light emitting device

Claims (6)

formed at a junction between the p layer and the n layer, a p layer made of an indirect transition semiconductor doped with a p-type impurity, an n layer made of an indirect transition semiconductor doped with an n-type impurity, and the n-type impurity. A pn junction layer, wherein electrons are injected when a voltage is applied, and electrons are applied to thereby form a part or all of the p layer, the pn junction layer, and the n layer. A light emitting element that emits light,
A first electrode formed on one surface in the thickness direction of the light emitting element;
A second electrode formed on the other surface in the thickness direction of the light emitting element;
A buffer member disposed on a surface of the first electrode opposite to the light emitting element;
A base disposed on a surface of the second electrode opposite to the light emitting element;
A first joining member provided between the first electrode and the cushioning material and joining them;
A second joining member provided between the second electrode and the base and joining them;
With
The melting point of the first bonding member is higher than the heat generation temperature of the light emitting element after voltage application,
The buffer member has higher rigidity than the light emitting element,
The melting point of the second bonding member is lower than the heat generation temperature of the light emitting element after the voltage is applied, and the second bonding member is heated by the heat of the light emitting element transmitted through the second electrode. A light-emitting device, wherein the light-emitting device changes to a fluid having the same.   The light emitting device according to claim 1, wherein the buffer member has a thermal conductivity greater than or equal to the base.   The second bonding member is disposed between the second electrode and the base, and the second bonding member is more than the first bonding member disposed between the first electrode and the cushioning material. The light emitting device according to claim 1, wherein the light emitting device has a large thickness. The first electrode is disposed on one entire surface of the light emitting element,
The first bonding member is provided on the entire surface of the first electrode,
The light-emitting device according to claim 1, wherein the buffer member is bonded so as to cover the entire surface of the first electrode. The second electrode is disposed on the entire other surface of the light emitting element,
The second bonding member is provided on the entire surface of the second electrode,
The light emitting device according to claim 1, wherein the base is joined so as to cover the entire surface of the second electrode. The base is disposed on the p layer side of the light emitting element,
The light-emitting device according to claim 1, wherein the buffer material is disposed on the n-layer side of the light-emitting element.

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