CN215645421U - Surface emitting laser device - Google Patents

Abstract

The application discloses a surface emitting laser device. The surface emitting laser device is used for generating a laser beam and comprises an epitaxial lamination body, a first electrode layer and a second electrode layer, wherein the first electrode layer and the second electrode layer are connected with the epitaxial lamination body. The surface emitting laser device comprises an interface metal compound layer formed by local annealing treatment of the first electrode layer or the second electrode layer by laser, wherein the interface metal compound layer is positioned between the first electrode layer and the epitaxial stacked body or between the second electrode layer and the epitaxial stacked body, and the interface metal compound layer is connected with the epitaxial stacked body. When local annealing treatment is carried out, only the surface of the first electrode layer or the second electrode layer is heated, so that the inside of the surface emitting laser device cannot be damaged due to stress change caused by high temperature, and the yield can be effectively improved.

Description

Surface emitting laser device

Technical Field

The present invention relates to a laser device, and more particularly, to a surface emitting laser device.

Background

Compared with the conventional edge-emitting laser, a Vertical-cavity surface-emitting laser (VCSEL) has the advantages of lower power consumption and easier coupling with an optical fiber, and is one of the light-emitting devices that are currently attracting attention. The conventional vertical cavity surface emitting laser includes at least a P-type electrode, an N-type electrode, an active layer for generating photons, and an upper Bragg Reflector (DBR) and a lower DBR located at both sides of the active layer. A current is injected into the active layer through the P-type electrode and the N-type electrode to excite photons, and a vertical resonant cavity is formed by using upper and lower Bragg reflectors (DBRs), so that a laser beam emitted from the surface of the element (i.e., in a direction perpendicular to the active layer) can be generated.

In a conventional manufacturing process of a vertical common cavity surface emitting laser, a plurality of stacked structures for generating a laser beam, which include an active layer for generating photons and upper and lower Bragg reflectors (DBRs) respectively located at two sides of the active layer, are first fabricated in a plurality of device regions on a semiconductor wafer. Then, the semiconductor wafer is thinned from the back side of the semiconductor wafer, and two electrode layers are formed on the front side and the back side of the semiconductor wafer respectively.

However, after the electrode layers are formed, the entire semiconductor wafer needs to be thermally annealed by furnace heating, so that each electrode layer can form a good ohmic contact with the lower bragg reflector (or the upper bragg reflector). Generally, heating above 400 ℃ is usually required to form a good ohmic contact. However, the thinned semiconductor wafer is easily warped, and a plurality of epitaxial layers made of different materials are formed on the semiconductor wafer and have certain internal stress.

Particularly, for fabricating the oxide VCSEL, an oxide layer for limiting current is formed therein, and a difference between thermal expansion coefficients of the oxide layer and other semiconductor materials is larger. Therefore, when the furnace tube is used to perform thermal annealing on the entire semiconductor wafer, the internal stress of the semiconductor wafer is easily increased to cause the semiconductor wafer to crack, thereby reducing the process yield. Meanwhile, thermal stress may remain in the laser device, which may reduce the lifetime of the device and affect the light-emitting characteristics thereof. Therefore, how to avoid the above problems to improve the process yield and device lifetime of the laser device is still one of the important issues to be solved by the industry.

SUMMERY OF THE UTILITY MODEL

The present disclosure provides a surface emitting laser device to overcome the shortcomings of the prior art, so as to avoid increasing the internal stress inside the surface emitting laser device, and to have a better manufacturing yield and a longer device life.

In order to solve the above-mentioned problems, one of the technical solutions of the present application is to provide a surface emitting laser device, which includes an epitaxial stacked body, a first electrode layer, a second electrode layer, and a first interfacial metal compound layer formed by local annealing. The epitaxial stack includes a substrate, a first reflector layer, an active layer and a second reflector layer. The first reflector layer, the active layer and the second reflector layer are positioned on the substrate, and the active layer is positioned between the first reflector layer and the second reflector layer to generate a laser beam. The first electrode layer is located on the epitaxial stacked body, and the second electrode layer is located on the second reflector layer. A current path passing through the active layer is defined between the second electrode layer and the first electrode layer, and the second electrode layer has an aperture for defining a light emitting region. The first interface metal compound layer is located between the first electrode layer and the epitaxial stacked body.

Furthermore, the first interface metal compound layer is located between the substrate and the first electrode layer, the first electrode layer includes a first metal layer, a second metal layer and a third metal layer connected with the first interface metal compound layer, and the second metal layer is located between the first metal layer and the third metal layer.

Further, the first interfacial metal compound layer contains at least two kinds of atoms, one of which is the same kind of atom as that of the first metal layer and the other of which is the same kind of atom as that of the substrate.

Further, the thickness of the first electrode layer is between

To

And the surface roughness of the first electrode layer is between 0.2 μm and 0.5 μm.

Further, the thickness of the first interfacial metal compound layer is between

To

Furthermore, the second electrode layer comprises a second conductive layer and a second interface metallic compound layer formed by local annealing treatment, and the second interface metallic compound layer is positioned between the second conductive layer and the second reflector layer.

Furthermore, the cross-sectional widths of the second reflective mirror layer and the active layer are smaller than that of the first reflective mirror layer to form a platform part together, and the first reflective mirror layer and the substrate form a base part together.

Furthermore, the first electrode layer and the second electrode layer are both located on the same side of the substrate, and the first interfacial metal compound layer is located between the first electrode layer and the first reflector layer and is annular around the platform portion.

Furthermore, the epitaxial stack has an oxide trench extending from the second reflector layer toward the substrate.

Furthermore, the epitaxial stack further includes a current confinement layer extending from a sidewall of the oxide trench to a position below the second electrode layer and defining a confinement hole corresponding to the light emitting region.

Furthermore, the surface emitting laser device further comprises a flat layer filled in the oxidation trench.

In order to solve the above technical problem, another technical solution adopted by the present application is to provide a laser device, which includes an epitaxial stacked body, a first electrode layer and a second electrode layer, wherein the first electrode layer and the second electrode layer are connected to the epitaxial stacked body, and the surface emitting laser device further includes at least one interface metal compound layer formed by local annealing, the interface metal compound layer is located between the first electrode layer and the epitaxial stacked body or between the second electrode layer and the epitaxial stacked body, and the interface metal compound layer is connected to the epitaxial stacked body.

Further, the interface metal compound layer is located between the first electrode layer and the epitaxial stacked body.

Further, the thickness of the first electrode layer is between

To

And the surface roughness of the first electrode layer is between 0.2 μm and 0.5 μm.

Further, the thickness of the interfacial metal compound layer is between

To

One of the advantages of the present application is that the surface emitting laser device provided by the present application can avoid increasing the internal stress of the surface emitting laser device when forming ohmic contact by "at least one interface metal compound layer formed by local annealing is located between the first electrode layer and the epitaxial stacked body or between the second electrode layer and the epitaxial stacked body", so that the surface emitting laser device has a longer element life and stable light extraction characteristics. When local annealing treatment is carried out, only the surface layer of the first or the second electrode layer is heated, so that the inside of the surface emitting laser device cannot be damaged due to stress change caused by high temperature, and the yield can be effectively improved.

For a better understanding of the nature and technical content of the present application, reference should be made to the following detailed description and accompanying drawings which are provided for purposes of illustration and description only and are not intended to limit the present application.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without exceeding the protection scope of the present application.

Fig. 1 is a schematic cross-sectional view of a surface emitting laser device according to a first embodiment of the present application.

Fig. 2 is an enlarged schematic view of section II of fig. 1.

FIG. 3 is an electron micrograph of an electrode layer and an epitaxial stacked body according to an embodiment of the present application.

Fig. 4 is a schematic cross-sectional view of a surface emitting laser device according to a second embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the description of the embodiments is only intended to facilitate the understanding of the methods and their core concepts of the present application. Meanwhile, a person skilled in the art should, according to the idea of the present application, change or modify the embodiments and applications of the present application based on the scope of the present application. In view of the above, the description should not be taken as limiting the application.

The following is a description of embodiments of the "surface emitting laser device" disclosed in the present application with reference to specific embodiments, and those skilled in the art will understand the advantages and effects of the present application from the disclosure of the present application. The present application is capable of other and different embodiments and its several details are capable of modifications and variations in various respects, all without departing from the present application. The drawings in the present application are for illustrative purposes only and are not intended to be drawn to scale. The following embodiments will further explain the related art of the present application in detail, but the disclosure is not intended to limit the scope of the present invention. In addition, the term "or" as used herein should be taken to include any one or combination of more of the associated listed items as the case may be.

[ first embodiment ]

Referring to fig. 1 to 2, a first embodiment of the present application provides a surface emitting laser device. In the present embodiment, the surface emitting laser device M1 is a vertical cavity surface emitting laser device. Further, the surface emitting laser device M1 in fig. 1 is an oxidation laser device, but the present application is not limited thereto. The surface emitting laser device M1 includes an epitaxial stack 10, a first electrode layer 11, a second electrode layer 12, and at least one interface metal compound layer L1(L2) formed by local annealing, wherein the first electrode layer 11 and the second electrode layer 12 are both located on the epitaxial stack 10.

In detail, the epitaxial stack 10 includes a substrate 100, a first mirror layer 101, an active layer 102, and a second mirror layer 103. The first mirror layer 101, the active layer 102, and the second mirror layer 103 are all disposed on the substrate 100, and the active layer 102 is disposed between the first mirror layer 101 and the second mirror layer 103.

The substrate 100 may be a doped group III-V semiconductor substrate, such as a gallium arsenide N-type (GaAs) substrate, an arsenic phosphide N-type (InP) substrate, an Aluminum Nitride (AIN) substrate, or an Indium Nitride (InN) substrate. In addition, the substrate 100 has a top surface and a bottom surface opposite to the top surface. The first mirror layer 101, the active layer 102 and the second mirror layer 103 are sequentially disposed on the top surface of the substrate 100.

The first mirror layer 101 and the second mirror layer 103 may be Distributed Bragg Reflectors (DBRs) formed by alternately stacking two kinds of thin films having different refractive indexes so as to emit a light beam having a predetermined wavelength.

The first mirror layer 101 and the second mirror layer 103 are formed by stacking a plurality of pairs of films with high refractive index and films with low refractive index. In one embodiment, the first mirror layer 101 is an n-type DBR mirror and the second mirror layer 103 is a p-type DBR mirror.

The active layer 102 is formed on the first mirror layer 101 and includes a plurality of layers for forming multiple quantum wells, such As a plurality of layers of gallium arsenide (gaas) and aluminum gallium arsenide (AlyGa (1-y) As) which are alternately stacked. The active layer 102 is disposed between the first mirror layer 101 and the second mirror layer 103 for generating an initial beam when excited by electric energy. The initial beam generated by the active layer 102 is amplified by reflection resonance back and forth between the first mirror layer 101 and the second mirror layer 103, and finally exits from the second mirror layer 103.

In the embodiment, the cross-sectional widths of the second mirror layer 103 and the active layer 102 are smaller than the cross-sectional width of the first mirror layer 101 (or the substrate 100) to form a platform portion 10a, and the first mirror layer 101 and the substrate 100 form a base portion 10 b. Accordingly, the base portion 10b includes at least the substrate 100 and the first mirror layer 101, and the mesa portion 10a includes at least the active layer 102 and the second mirror layer 103.

In addition, in the present embodiment, the epitaxial stack 10 further includes a current confinement layer 104. The current confinement layer 104 is located within the second mirror layer 103 and has a confinement hole 104H corresponding to the light emitting area a 1. The current confinement layer 104 within the second mirror layer 103 will have a higher resistance value, driving current to bypass the current confinement layer 104 with a high resistance value and only pass through the confinement holes 104H. Accordingly, the current density of the current injected into the active layer 102 can be increased. In one embodiment, the current confinement layer 104 may be formed by oxidizing one of the layers in the second mirror layer 103 by a lateral oxidation process.

Furthermore, the epitaxial stack 10 of the present embodiment has at least one oxide trench H1, and the oxide trench H1 extends from the second mirror layer 103 toward the substrate 100. In one embodiment, the depth of the oxide trench H1 is greater than the thickness of the second mirror layer 103. In another embodiment, the depth of the oxide trench H1 is greater than or equal to the sum of the thicknesses of the second mirror layer 103 and the active layer 102. That is, the oxidation trench H1 extends toward the substrate 100 into the first mirror layer 101 below the active layer 102.

In addition, in the present embodiment, the oxidation trench H1 has a ring shape in a plan view and surrounds the terrace portion 10 a. Accordingly, one sidewall of the oxidation trench H1 is the sidewall of the mesa portion 10 a. In other embodiments, the oxidation trench H1 is plural in number and is circumferentially disposed around the terrace portion 10 a.

In the present embodiment, the current confinement layer 104 is formed by performing an oxidation process. Specifically, at least one high aluminum-containing layer is formed in the plurality of layers of the second mirror layer 103. Therefore, when the oxidation process is performed, the high aluminum content layer is easily oxidized from the portion exposed on the sidewall of the oxide trench H1, thereby forming the current confinement layer 104. Accordingly, the current confinement layer 104 extends radially from the sidewall of the oxide trench H1 to below the second electrode layer 12, thereby defining the via 104H. However, in other embodiments, the current confinement layer 104 may be a hydrogen ion implantation layer formed in the second mirror layer 103 by high-energy hydrogen ion implantation.

Referring to fig. 1, the first electrode layer 11 and the second electrode layer 12 are both located on the epitaxial stack 10, and a current path passing through the active layer 102 is defined between the first electrode layer 11 and the second electrode layer 12.

In the present embodiment, the first electrode layer 11 and the second electrode layer 12 are respectively located on opposite sides of the substrate 100. Further, the first electrode layer 11 is located on the bottom surface of the substrate 100, and the second electrode layer 12 is located on the second mirror layer 103. That is, the second electrode layer 12 is located on the island-shaped terrace portion 10a, and the first electrode layer 11 is located on the base portion 10 b. The first electrode layer 11 and the second electrode layer 12 may be a single metal layer, an alloy layer, or a stack of different metal materials. At least one of the first electrode layer 11 and the second electrode layer 12 has an Interfacial Metal Compound (IMC) layer formed by local annealing.

Referring to fig. 1, the first interfacial metal compound layer L1 is located between the first electrode layer 11 and the epitaxial stacked body 10.

Referring to fig. 2, in detail, the first electrode layer 11 of the present embodiment includes a first metal layer 110a, a second metal layer 110b and a third metal layer 110c connected to the first interfacial metal compound layer L1, and the second metal layer 110b is located between the first metal layer 110a and the third metal layer 110 c. That is, in the embodiment of the present application, the first electrode layer 11 is a stacked structure formed by three metal layers. The material of the first metal layer 110a is germanium gold, and the material of the second metal layer 110b and the third metal layer 110c is gold, copper, palladium, titanium, germanium, tungsten, or any combination thereof. In another embodiment, the first electrode layer 11 may include only two metal layers, as long as ohmic contact can be formed between the first electrode layer 11 and the epitaxial stacked body 10, and the material and structure of the first electrode layer 11 are not limited in this application.

It should be noted that, in the embodiment of the present application, after the first electrode layer 11 is formed on the bottom surface of the substrate 100, the first electrode layer 11 and the substrate 100 are locally annealed to promote the reaction between the first electrode layer 11 and the substrate 100, so as to form the first interfacial metal compound layer L1 between the first electrode layer 11 and the substrate 100. Accordingly, the first interfacial metallic compound layer L1 includes at least two kinds of atoms, one of which is the same kind of atom as that of the first metal layer 110 a. The first interfacial metal compound layer L1 may contain another kind of atoms that are the same as the atoms of the substrate 100.

For example, if the material of the first metal layer 110a is germanium and the material of the substrate 100 is gallium arsenide, the first interfacial metal compound layer L1 includes germanium atoms, arsenic atoms and gallium atoms. However, the present application is not limited to this example.

In addition, in the embodiment of the present application, the first electrode layer 11 and the substrate 100 are locally annealed by using laser to form the first interfacial metallic compound layer L1 while forming a good ohmic contact. The temperature of other portions of the epitaxial stack 10, including the first mirror layer 101, the second mirror layer 103 and the active layer 102, is not raised during the heating process, thereby avoiding an increase in internal stress of the epitaxial stack 10. Thus, it is avoided that the lifetime and light-emitting characteristics of the surface emitting laser device M1 are affected by the excessive internal stress of the epitaxial stacked body 10 due to heat. In addition, if the internal stress of the epitaxial stacked body 10 is too high, the resistance of the surface emitting laser device M1 against electrostatic discharge (ESD) may be affected, and thus, reducing the internal stress of the epitaxial stacked body 10 may also increase the resistance of the surface emitting laser device M1 against electrostatic discharge.

The thickness of the first electrode layer is between

To

The thickness of the first interfacial metal compound layer L1 is between

To

In addition, the surface roughness of the first electrode layer 11 is between 0.2 μm and 1.0 μm.

In one embodiment, the surface roughness of the first electrode layer 11 is about 0.5 μm to 1 μm before the local annealing is performed. After the local annealing treatment is performed, the surface roughness of the first electrode layer 11 is about 0.2 μm to 0.5 μm, and the surface roughness of the first interfacial metallic compound layer L1 is also between 0.2 μm to 0.5 μm. That is, after the local annealing treatment is performed, the surface roughness of the first electrode layer 11 can be reduced. In another embodiment, if the first electrode layer 11 itself already has a relatively low surface roughness (about 0.2 μm to 0.5 μm), the surface roughness of the first electrode layer 11 does not change much after the local annealing process is performed.

Referring to fig. 3, fig. 3 is an electron microscope photograph of an electrode layer and an epitaxial stacked body according to an embodiment of the present application. The sem photo of fig. 3 shows a cross-section of the substrate 100 and the first electrode layer 11 according to the embodiment of the present invention. The first interfacial metal compound layer L1 of the embodiment of the present application has a surface topography with large undulations in local regions.

In addition, in order to form a better ohmic contact between the substrate 100 and the first electrode layer 11, the heating temperature is at least 400 ℃, and even higher temperature is required. However, in the prior art, when the whole epitaxial stacked body is heated by a furnace tube, the temperature of the epitaxial stacked body 10 is limited, and the heating is only to 400 ℃.

However, in the present embodiment, when the laser is used to locally heat, only the junction area between the substrate 100 and the first electrode layer 11 will be heated to a temperature above 400 ℃, and other parts of the epitaxial stacked body 10 (such as the first and second mirror layers 101,103 and the active layer 102) will not be heated too high simultaneously. Therefore, not only ohmic contact with low impedance can be formed between the first electrode layer 11 and the substrate 100, but also increase of internal stress of the epitaxial stacked body 10 can be avoided. In one embodiment, the voltage Vf to be applied for driving the surface emitting laser is between 5.0v (volt) and 7.0v (volt) when the ohmic contact is not formed between the first electrode layer 11 and the epitaxial stack 10 through the thermal annealing process. After ohmic contact is formed by the thermal annealing process, a voltage (Vf) to be applied for driving the surface emitting laser may be reduced to about 1.5v (volt) to 2.5v (volt).

Referring to fig. 1 again, in the embodiment of fig. 1, the second electrode layer 12 has an aperture (not numbered) for defining a light emitting area a1, and the aperture corresponds to the limiting hole 104H of the current limiting layer 104, so that the laser beam generated by the active layer 102 can be emitted through the aperture. In an embodiment, the second electrode layer 12 has an annular portion.

In the embodiment of fig. 1, the surface emitting laser apparatus M1 further includes a second interfacial metal compound layer L2 formed by a local annealing process. The second interfacial metal compound layer L2 is located between the second electrode layer 12 and the second mirror layer 103. The material of the second electrode layer 12 may be gold, tungsten, germanium, palladium, titanium, or any combination thereof. In another embodiment, the second electrode layer 12 has a similar stack structure to the first electrode layer 11, that is, includes at least two metal layers, which is not limited in this application.

In addition, similar to the first interfacial metallic compound layer L1, the second interfacial metallic compound layer L2 is formed by locally heating the second electrode layer 12 and the second mirror layer 103 with laser light. Accordingly, the second interfacial metal compound layer L2 contains at least two kinds of atoms, one of which is the same kind of atoms as the second electrode layer 12. The second interfacial metal compound layer L2 contains another kind of atoms that are the same as the atoms of the second mirror layer 103.

For example, if the material of the second electrode layer 12 is a germanium-gold alloy and the material of the topmost layer of the second mirror layer 103 is aluminum-gallium arsenide, the second interfacial metal compound layer L2 may include gold atoms, germanium atoms, arsenic atoms, aluminum atoms and gallium atoms, but the application is not limited thereto.

In addition, since the second electrode layer 12 includes a ring-shaped portion, the second interfacial metal compound layer L2 formed between the second mirror layer 103 and the second electrode layer 12 also has a ring shape and surrounds the light emitting region a 1.

Please continue to refer to fig. 1. The surface emitting laser M1 of the present embodiment further includes a current spreading layer 13 on the second mirror layer 103 and electrically connected to the second electrode layer 12. In one embodiment, the current spreading layer 13 is made of a conductive material, so that the current injected from the second mirror layer 103 into the active layer 102 is uniformly distributed. In addition, the material constituting the current spreading layer 13 is a material that is transparent to a laser beam in order to avoid excessively sacrificing the light emission efficiency of the surface emitting laser device M1. For example, when the wavelength of the laser beam is 850nm, the material constituting the current spreading layer 13 may be a doped semiconductor material, such as heavily doped gallium arsenide.

In addition, the surface emitting laser device M1 of the embodiment of the present application further includes a protection layer 14 and a planarization layer PL. The passivation layer 14 covers the light emitting region a1 and covers the inner wall of the oxide trench H1 to prevent moisture from invading the interior of the epitaxial stacked body 10 and affecting the light emitting characteristics or lifetime of the surface emitting laser device M1. In one embodiment, the protective layer 14 may be selected from a material resistant to moisture, such as silicon nitride, aluminum oxide, or a combination thereof, without limitation.

The planarization layer PL fills the oxide trench H1. In one embodiment, the top surface of the planarization layer PL is substantially flush with the top surface of the epitaxial stack 10. The material of the planarization layer PL is a polymer material, such as Polyimide (PI), Benzocyclobutene (BCB), or other suitable materials, but the application is not limited thereto.

It should be noted that, in the embodiment of fig. 1, the first electrode layer 11 and the second electrode layer 12 are respectively located on different sides of the substrate 100, however, in other embodiments, the first electrode layer 11 and the second electrode layer 12 may be both located on the same side of the substrate 100.

Fig. 4 is a schematic cross-sectional view of a laser device according to a second embodiment of the present application. The same elements of the surface emitting laser device M2 of the present embodiment as those of the surface emitting laser device M1 of the first embodiment have the same reference numerals, and the description of the same parts is omitted.

As shown in fig. 4, both the first electrode layer 11 and the terrace portion 10a are located on the base portion 10b, and therefore the first electrode layer 11 and the second electrode layer 12 are located on the same side of the substrate 100. In this embodiment, the first electrode layer 11 surrounds the terrace portion 10a and is disposed on the top surface of the first mirror layer 101. In addition, the first interfacial metal compound layer L1 is located between the first mirror layer 101 and the first electrode layer 11. Accordingly, in the present embodiment, the first interfacial metal compound layer L1 is in a ring shape surrounding the mesa portion 10 a.

Therefore, the present invention does not limit the positions where the first electrode layer 11 and the second electrode layer 12 are disposed, as long as a current path through the active layer 102 can be generated between the first electrode layer 11 and the second electrode layer 12. In addition, in the embodiment of the present invention, the first electrode layer 11 and the second electrode layer 12 located on the same side may be locally annealed by using a laser, so that good ohmic contacts are formed between the first electrode layer 11 and the first mirror layer 101 and between the second electrode layer 12 and the second mirror layer 103 in the same process, and the first and second interfacial metal compound layers L1 and L2 are formed.

[ advantageous effects of the embodiments ]

One of the advantages of the present application is that the surface emitting laser device M1, M2 provided herein can reduce the impedance between the first electrode layer 11 and the epitaxial stacked body 10 and the internal stress of the epitaxial stacked body 10 by "the first electrode layer 11 includes a first conductive layer 110 and a first interfacial metal compound layer L1 formed by local annealing, and the first interfacial metal compound layer L1 is located between the first electrode layer 11 and the epitaxial stacked body 10" or "at least one of the first electrode layer 11 or the second electrode layer 12 has an interfacial metal compound layer L1(L2) formed by local annealing".

In the present invention, when the first electrode layer 11 and the substrate 100 (or the second electrode layer 12 and the second mirror layer 103) are locally heated by laser light to form ohmic contact, the first interfacial metal compound layer L1 (or the second interfacial metal compound layer L2) is formed together. Therefore, the regions other than the specific region heated by the laser light are not heated at the same time in the epitaxial stacked body 10. Therefore, the surface emitting laser devices M1 and M2 can be prevented from cracking due to excessive internal stress, and the process yield is improved. That is, only the surface layer of the first or second electrode layer 11,12 is heated during the local annealing process, so that the surface emitting laser devices M1, M2 are not damaged due to stress variation caused by high temperature, and the yield can be effectively improved.

On the other hand, it is possible to prevent the epitaxial stacked body 10 from being affected by the excessive internal stress, which may affect the lifetime and light extraction characteristics of the surface emitting laser devices M1 and M2. In addition, the ability of the surface emitting laser devices M1 and M2 to resist electrostatic discharge can be increased by reducing the internal stress of the epitaxial stacked body 10.

Especially, when the laser devices M1 and M2 are oxide vertical cavity surface emitting laser devices, the current confinement layer 104 in the epitaxial stack 10 is an oxide layer, and the difference between the thermal expansion coefficients of the oxide layer and other semiconductor epitaxial layers makes it easier to accumulate internal stress during the temperature raising and lowering process. However, the above problems can be avoided by the technical means of the present invention.

The above description is only a preferred embodiment of the present application, and not intended to limit the scope of the claims of the present application, so that all equivalent technical changes made by using the contents of the specification and the drawings of the present application are included in the scope of the claims of the present application.

Claims (15)

1. A surface-emitting laser device, comprising:

an epitaxial stack including a substrate, a first reflector layer, an active layer and a second reflector layer, wherein the first reflector layer, the active layer and the second reflector layer are disposed on the substrate, and the active layer is disposed between the first reflector layer and the second reflector layer to generate a laser beam;

a first electrode layer located on the epitaxial stacked body;

a second electrode layer on the second mirror layer, wherein the second electrode layer defines a current path through the active layer with the first electrode layer, and the second electrode layer has an aperture for defining a light-emitting region; and

a first interface metallic compound layer formed by local annealing treatment, wherein the first interface metallic compound layer is positioned between the first electrode layer and the epitaxial stacked body.

2. The surface-emitting laser device of claim 1, wherein the first interfacial metal compound layer is located between the substrate and the first electrode layer, the first electrode layer comprises a first metal layer, a second metal layer and a third metal layer connected to the first interfacial metal compound layer, and the second metal layer is located between the first metal layer and the third metal layer.

3. The surface-emitting laser device according to claim 2, wherein the first interfacial metal compound layer contains at least two kinds of atoms, one of which is the same kind of atom as that of the first metal layer and the other of which is the same kind of atom as that of the substrate.

4. The surface-emitting laser device according to claim 1, wherein the first electrode layer has a thickness between

To

And the surface roughness of the first electrode layer is between 0.2 μm and 0.5 μm.

5. The surface-emitting laser device according to claim 1, wherein the thickness of the first interfacial metal compound layer is between

To

6. The surface-emitting laser device of claim 1, wherein the second electrode layer comprises a second conductive layer and a second interfacial metal compound layer formed by local annealing, the second interfacial metal compound layer being located between the second conductive layer and the second mirror layer.

7. The surface-emitting laser device of claim 1, wherein the second mirror layer and the active layer have a smaller cross-sectional width than the first mirror layer to form a mesa, and the first mirror layer and the substrate form a base portion.

8. The surface-emitting laser device according to claim 7, wherein the first electrode layer and the second electrode layer are on the same side of the substrate, and the first interfacial metal compound layer is between the first electrode layer and the first mirror layer and is in a ring shape around the mesa portion.

9. The surface-emitting laser device of claim 1, wherein the epitaxial stack has an oxide trench extending from the second reflector layer toward the substrate.

10. The surface-emitting laser device of claim 9, wherein the epitaxial stack further comprises a current confinement layer extending from a sidewall of the oxide trench to below the second electrode layer and defining a confinement hole corresponding to the light-emitting region.

11. The surface-emitting laser device of claim 9, further comprising a planarization layer filling the oxide trench.

12. A surface emitting laser device comprises an epitaxial stacked body, a first electrode layer and a second electrode layer, wherein the first electrode layer and the second electrode layer are connected with the epitaxial stacked body.

13. The surface-emitting laser device according to claim 12, wherein the interface metal compound layer is located between the first electrode layer and the epitaxial stacked body.

14. The surface-emitting laser device according to claim 12, wherein the first electrode layer has a thickness between

To

And the surface roughness of the first electrode layer is between 0.2 μm and 0.5 μm.

15. The surface-emitting laser device according to claim 12, wherein the thickness of the interfacial metal compound layer is between

To

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