CN217281626U - Semiconductor laser device - Google Patents

Abstract

The application discloses semiconductor laser, semiconductor laser includes semiconductor substrate, functional layer and laser instrument component, semiconductor substrate has relative first surface and second surface, the functional layer is located the first surface, the laser instrument component is located one side that the functional layer deviates from semiconductor substrate, wherein this functional layer can improve the speed that laser instrument component work heat conduction to semiconductor substrate, and can reduce semiconductor substrate to the reflection of laser instrument component outgoing light, semiconductor laser just so can effectively reduce the reflection in the radiating while, the heat transfer problem and the light reflection problem of semiconductor have been solved.

Description

Semiconductor laser device

Technical Field

The application relates to the field of laser display, in particular to a semiconductor laser.

Background

Semiconductor lasers are devices that generate laser light by using a certain semiconductor material as a working substance. The operating principle is that the population inversion of non-equilibrium carriers is realized between the energy bands (conduction band and valence band) of the semiconductor substance or between the energy bands of the semiconductor substance and the energy levels of impurities (acceptor or donor) through a certain excitation mode, and when a large number of electrons in the population inversion state are combined with holes, the stimulated emission effect is generated. The device has the characteristics of small volume, light weight, reliable operation, low power consumption, high efficiency and the like, and is widely applied to multiple fields of military affairs, industrial processing, communication, information storage, medical treatment and the like.

With the continuous iterative progress of the technology, the semiconductor laser is widely used in more and more fields, and the power and the heat productivity of the semiconductor laser are continuously improved. The temperature that cannot be dissipated in time may cause the working performance of the semiconductor laser to be reduced, the light emitting efficiency to be reduced, the stability and reliability to be deteriorated, and even damage to be generated. However, the light emitting efficiency of a general semiconductor laser substrate is affected to some extent by the reflection of light. Therefore, in order to further expand the application of the semiconductor laser, a semiconductor laser scheme capable of effectively dissipating heat while reducing reflection becomes a very important research target.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present application provides a semiconductor laser, which has the following scheme:

a semiconductor laser, comprising:

a semiconductor substrate having opposing first and second surfaces;

a functional layer on the first surface;

a laser element located on a side of the functional layer facing away from the semiconductor substrate;

the functional layer is used for increasing the speed of conducting the working heat of the laser element to the semiconductor substrate and reducing the reflection of the semiconductor substrate to the emergent ray of the laser element.

Preferably, in the semiconductor laser, the functional layer includes a graphene layer, and the graphene layer includes a plurality of hollow regions penetrating through the graphene layer.

Preferably, in the semiconductor laser, the semiconductor substrate is an SiC substrate, and the functional layer is a graphene layer that is thermally converted on a side of the SiC substrate corresponding to the first surface.

Preferably, in the semiconductor laser, the graphene layer is a graphene deposition layer.

Preferably, in the semiconductor laser, a depth of the hollowed-out region is not less than a thickness of the graphene layer.

Preferably, in the semiconductor laser, the hollow areas are arranged in an array, and the hollow areas are any one of circular, triangular and rectangular.

Preferably, in the semiconductor laser, the thickness of the graphene layer is less than 10 nm.

Preferably, in the semiconductor laser, the laser element includes:

the epitaxial layer is positioned on one side, away from the semiconductor substrate, of the functional layer;

the active layer is positioned on one side, away from the functional layer, of the epitaxial layer, and part of the epitaxial layer is exposed out of the active layer;

the first electrode is positioned on one side, away from the epitaxial layer, of the active layer;

and the second electrode is positioned on the surface of the active layer exposed out of the epitaxial layer.

As can be seen from the above description, the semiconductor laser provided in the present application includes a semiconductor substrate, a functional layer and a laser element, the semiconductor substrate has a first surface and a second surface opposite to each other, the functional layer is located on the first surface, and the laser element is located on a side of the functional layer away from the semiconductor substrate, where the functional layer can increase a rate of conducting operating heat of the laser element to the semiconductor substrate, and can reduce reflection of the semiconductor substrate to outgoing light of the laser element, so that the semiconductor laser can effectively dissipate heat while reducing reflection, and a heat transfer problem and a light reflection problem of a semiconductor are solved.

Drawings

In order to more clearly illustrate the embodiments of the present application or technical solutions in related arts, the drawings used in the description of the embodiments or prior arts will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

The structures, proportions, and dimensions shown in the drawings and described in the specification are for illustrative purposes only and are not intended to limit the scope of the present disclosure, which is defined by the claims, but rather by the claims, it is understood that these drawings and their equivalents are merely illustrative and not intended to limit the scope of the present disclosure.

Fig. 1 is a schematic structural diagram of a semiconductor laser provided in an embodiment of the present application;

fig. 2 is a top view of a substrate and a graphene layer of a semiconductor laser according to an embodiment of the present disclosure;

fig. 3 is a top view of another implementation manner of a graphene layer hollow-out region of a semiconductor laser according to an embodiment of the present disclosure;

fig. 4 is a top view of another implementation manner of a hollow-out region of a graphene layer of a semiconductor laser according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of another semiconductor laser device using SiC as a substrate in the embodiment of the present application;

FIG. 6 is a schematic diagram of another laser structure based on the substrate of the present application;

fig. 7-8 are schematic flow charts illustrating a method for fabricating a semiconductor laser according to an embodiment of the present disclosure.

Detailed Description

Embodiments of the present application will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the application are shown, and in which it is to be understood that the embodiments described are merely illustrative of some, but not all, of the embodiments of the 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 conventional laser heat dissipation scheme mainly needs to solve two problems, one is heat transfer of the laser, and the other is heat dissipation. The common method for solving the heat transfer problem is to use a low-temperature cooling liquid to transfer away the heat of the laser by a large temperature difference. However, this approach is limited by the usage scenario and requires strict control. Another common way is to use a high thermal conductivity material to reduce the thermal resistance between the chip and the cooling system, such as using a diamond film.

However, for solving the heat dissipation problem of the laser by using the above method, the following problems may occur:

since the low-temperature cooling liquid such as liquid nitrogen may cause frosting of the laser system and influence light emission, precise control is required and the use scene is limited. The high-efficiency heat conduction material, such as a diamond film, has high cost, is difficult to prepare and cannot be used in a large range.

The reflection of laser light in the substrate is reduced mainly by using an anti-reflection film with suitable refractive index and thickness.

However, the following problems exist for solving the reflection of laser light emitted from the substrate by using the above method:

although the technology of the anti-reflection film is mature, the reliability of the laser is affected in many scenes due to the limitation of the working conditions. On the other hand, the coating of the anti-reflection film also increases the process complexity and cost of the laser, the anti-reflection film has general heat resistance, the work under large temperature difference also has the risk of falling off because of different thermal expansion coefficients of the materials, and an additional coating process is required.

In order to solve the above problems, embodiments of the present application provide a semiconductor laser and a method for manufacturing the same, where a functional layer is disposed in the semiconductor laser, and the functional layer can improve the rate of conducting the operating heat of a laser element to a semiconductor substrate, and can reduce the reflection of the semiconductor substrate to the light emitted from the laser element, so that the semiconductor laser can reduce the reflection while effectively dissipating heat, and the problems of heat transfer and light reflection of the semiconductor are solved.

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, the present application is described in further detail with reference to the accompanying drawings and the detailed description.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a semiconductor laser provided in an embodiment of the present application, where the semiconductor laser includes:

a semiconductor substrate 1 having a first surface S1 and a second surface S2 opposite thereto;

a functional layer 2 located on said first surface S1;

a laser element 3 on the side of the functional layer 2 facing away from the semiconductor substrate 1;

the functional layer 2 is used for increasing the rate of conducting the working heat of the laser element 3 to the semiconductor substrate 1 and reducing the reflection of the semiconductor substrate 1 to the light emitted by the laser element 3.

In the semiconductor laser provided in the embodiment of the present application, the functional layer 2 is provided on the first surface S1 of the semiconductor substrate 1, and the laser component 3 is provided on the side of the functional layer 2 away from the semiconductor substrate 1. The functional layer 2 can effectively improve the speed of the conduction of the working heat of the laser element 3 to the semiconductor substrate 1, and can reduce the reflection of the semiconductor substrate 1 to the emergent light of the laser element 3.

The choice of the material of the semiconductor substrate 1 also has an influence on the operating performance and the light emitting effect of the semiconductor laser, and the materials for manufacturing the semiconductor substrate 1 are as follows: sapphire (Al2O3), silicon (Si), and silicon carbide (SiC), in addition to the above three commonly used substrate materials, also GaAS, AlN, ZnO, and the like can be used as the substrate. Sapphire is a relatively popular substrate material, which has good chemical stability, relatively mature manufacturing technology and does not absorb visible light, but has poor thermal conductivity. Silicon carbide is a good conductor of heat, and the heat conducting performance of the device can be obviously improved.

Referring to fig. 2, fig. 2 is a top view of a graphene layer of a semiconductor laser according to an embodiment of the present disclosure. The functional layer 2 is a graphene layer 4, and the graphene layer 4 comprises a plurality of hollow areas 5 penetrating through the graphene layer.

The functional layer 2 comprises a layer 4 of graphene, a two-dimensional material with a high thermal conductivity, almost tens and hundreds of times that of diamond, stoneThe ink-jet ink also has good optical characteristics and is structurally stable. The graphene layer 4 comprises a plurality of hollow areas 5 penetrating through the graphene layer, the hollow areas 5 are obtained by carrying out image processing on the graphene layer 4, and the image processing is to etch a certain shape through the graphene layer 4, so that the reflection structure of the graphene layer 4 is changed, and the purpose of reducing the reflectivity is achieved. Etching is generally performed using an ICP apparatus. Firstly, a photoresist is coated on the surface by a photoetching mode, and a patterned shape is exposed on the photoresist. Thereafter using the loaded SF ₆ And O ₂ The dry etching is carried out on the gas ICP etching equipment, parameter setting ranges of different equipment can be greatly different, the thickness of about 1um can be etched under general conditions, the time is controlled to be 5-8 minutes, the graphene etching method is simple, and the cost is low.

The graphene layer 4 and the substances of the laser element 3 growing into the hollow areas 5 can be equivalent to micro lenses, and the plurality of hollow areas 5 are arranged in an array mode to form a micro lens array.

The depth of the hollow-out area 5 is not less than the thickness of the graphene layer 4, so that reflection is effectively reduced, and the lighting effect is improved.

In the manner shown in fig. 2, the hollow areas 5 are illustrated as rectangles, it is obvious that in the embodiment of the present application, the implementation manner of the hollow areas 5 is not limited to the manner shown in fig. 2, the hollow areas 5 may be set to be arranged in an array based on requirements, and the hollow areas 5 are any one of circular, triangular and rectangular, as shown in fig. 3 or fig. 4.

Referring to fig. 3, fig. 3 is a top view of another implementation manner of the hollow area 5, in the implementation manner shown in fig. 3, a figure of the hollow area 5 is a triangle.

Referring to fig. 4, fig. 4 is a top view of another implementation manner of the hollow area 5, in the implementation manner shown in fig. 4, the figure of the hollow area 5 is a circle.

Referring to fig. 2, the graphene layer 4 has a thickness of less than 10 nm. Although the graphene has high thermal conductivity, the number of layers is better controlled to be a little less than the general heat dissipation requirement, so that the heating time can be reduced and the number of layers can be controlled under the condition of ensuring the precipitation of the surface layer Si.

One way is that the graphene layer 4 is a graphene deposition layer, and depositing graphene is also an optional scheme for preparing the graphene layer 4, and the deposition method of the graphene deposition layer includes: chemical Vapor Deposition (CVD). The preparation of the graphene by chemical vapor deposition is to place a planar substrate in a high-temperature decomposable precursor atmosphere, deposit carbon atoms on the surface of the substrate through high-temperature annealing to form the graphene, and finally remove the metal substrate by a chemical corrosion method to obtain the independent graphene sheet.

In another mode, the semiconductor substrate 1 is a SiC substrate, and the functional layer 2 is a graphene layer that is heat-converted on a side of the SiC substrate corresponding to the first surface S1. The SiC substrate mainly exerts the characteristics of heat dissipation and easiness in graphene growth, has low requirements on crystal forms and defects of materials, is not actually different from single crystal SiC or polycrystalline SiC, has the same effect on preparing the graphene layer 4, and can use a polycrystalline substrate or a low-cost single crystal substrate with more defects and unsuitability for other applications. The SiC substrate can form a single-layer graphene structure after being heated at 800-1000 ℃. In the embodiment, the temperature required for forming the graphene layer 4 on the surface of the SiC substrate by heating is 1500 ℃, the heating time is 10-300 min, and graphene materials with different thicknesses can be obtained.

Compared with a high-cost method for forming a graphene layer by deposition, the heating method has the advantages that the silicon carbide conversion graphene layer is heated, a high-cost deposition process is not needed, graphene is directly formed by heating the SiC substrate, the process is simple, the manufacturing cost is low, and the thickness of a device is not increased.

As described above, by providing the functional layer 2, the rate of conducting the operating heat of the laser element 3 to the semiconductor substrate 1 is increased, and the reflection of the laser element 3 by the semiconductor substrate 1 is reduced, which can be used to improve the light extraction efficiency and the heat dissipation efficiency of various semiconductor lasers. The structure of the semiconductor laser is not limited to that shown in fig. 5 and 6 below.

Referring to fig. 5, fig. 5 is a schematic structural diagram of another semiconductor laser provided in an embodiment of the present application, and based on the manner shown in fig. 1, the laser element 3 in fig. 5 includes:

an epitaxial layer 9 on the side of the functional layer facing away from the semiconductor substrate;

the active layer 10 is positioned on one side, away from the functional layer, of the epitaxial layer, and the active layer exposes a part of the epitaxial layer;

a first electrode 11 located on a side of the active layer facing away from the epitaxial layer;

and the second electrode 12 is positioned on the surface of the active layer exposed out of the epitaxial layer.

The laser element includes: epitaxial layer 9, active layer 10, first electrode 11 and second electrode 12

The semiconductor laser according to the embodiment of the present application includes a SiC substrate 8, a graphene layer 4, an epitaxial layer 9, an active layer 10, a first electrode 11, and a second electrode 12. The material of the laser element 3 grown to the hollow region 5 is grown from an epitaxial layer 9, the epitaxial layer 9 includes, but is not limited to, GaN, InP, GaAs, and the like, and the epitaxial layer 9 is a GaN epitaxial layer in fig. 6. The epitaxial layer 9 of the semiconductor laser is directly manufactured on the surface of the graphene layer 4, then the epitaxial layer 9 is processed to form a laser structure, the active layer 10 in fig. 6 is an AlGaN active layer, wherein the first electrode 11 can cover the AlGaN active layer 10, and the first electrode 11 becomes a metal reflective electrode, or a surface passivation layer can be added on the surface of the first electrode 11, the surface of the active layer 11 exposed out of the first electrode 11, the surface of the epitaxial layer 9 exposed out of the active layer 10, and the surface of the second electrode 12 to increase reflection.

Fig. 6 is a schematic view of a laser structure according to another embodiment of the present invention, and fig. 6 is a schematic view of another laser structure based on the substrate of the present invention. The laser structure shown in fig. 6 includes: a first electrode 13, a SiC substrate 14, a graphene layer 15, a buffer layer 16, an N-DBR layer 17, an active layer 18, a P-DBR layer 19, a resonant cavity 20, an ohmic contact layer 21, and a second electrode 22. The present application mainly provides a substrate scheme, and the upper layer laser scheme on the basis of the substrate scheme can be freely combined, and no matter DBR or quantum dot laser, etc., can be used for growth and technological processing on the substrate.

Based on the foregoing embodiments, another embodiment of the present application further provides a method for manufacturing a semiconductor laser, which is used to manufacture the semiconductor laser according to the foregoing embodiments, and the manufacturing method may be as shown in fig. 7 to 8.

Referring to fig. 7 to fig. 8, fig. 7 to fig. 8 are schematic flow charts of a manufacturing method of a semiconductor laser according to an embodiment of the present application, where the manufacturing method includes:

step S1: as shown in fig. 7, a semiconductor substrate 1 is provided, having a first surface S1 and a second surface S2 opposite to each other;

step S2: as shown in fig. 8, the functional layer 2 is formed on the first surface S1;

step S3: forming a laser element 3 on the side of the functional layer 2 away from the semiconductor substrate 1, wherein the prepared semiconductor laser is as shown in fig. 1;

the functional layer 2 is used for increasing the rate of conducting the working heat of the laser element 3 to the semiconductor substrate 1 and reducing the reflection of the semiconductor substrate 1 to the emergent light of the laser element 3.

Forming a functional layer 2 on said first surface S1, comprising:

forming a graphene layer 4 as the functional layer 2 on the first surface S1, wherein the graphene layer 4 includes a plurality of hollow areas 5 penetrating through the graphene layer 4.

The functional layer 2 comprises a graphene layer 4, the graphene layer 4 comprises a plurality of hollow areas 5 penetrating through the graphene layer 4, the hollow areas 5 are obtained by etching the graphene layer 4, and the reflection structure of the graphene layer 4 is changed through etching. The etching step comprises: coating glue on the surface in a photoetching mode, exposing a graphical shape on the glue, and performing dry etching by using etching equipment.

The semiconductor substrate 1 is a SiC substrate;

forming a graphene layer 4 as the functional layer 2 on the first surface S1, including:

heating the SiC substrate at a preset temperature, so that the side of the SiC substrate corresponding to the first surface S1 is converted into the graphene layer 4.

The semiconductor substrate 1 is a SiC substrate, and the step of forming the graphene layer 4 as the functional layer 2 on the first surface S1 of the SiC substrate includes: and heating the SiC substrate at 1500 ℃ for 10-300 min to form a graphene structure on the SiC substrate, wherein the heating time is different, and graphene materials with different thicknesses can be obtained.

Forming a graphene layer 4 as the functional layer 2 on the first surface S1, including:

depositing the graphene layer 4 on the first surface S1 by a deposition process.

In this embodiment, the graphene deposition layer is formed on the first surface S1 by a chemical vapor deposition method, which includes the steps of: and (3) placing the planar substrate in a high-temperature decomposable precursor atmosphere, depositing carbon atoms on the surface of the substrate through a high-temperature annealing process to form a graphene layer 4, and removing the metal substrate by using a chemical corrosion method.

The embodiments in the present description are described in a progressive manner, or in a parallel manner, or in a combination of a progressive manner and a parallel manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments can be referred to each other. The manufacturing method disclosed by the embodiment corresponds to the semiconductor laser disclosed by the embodiment, so that the description is simple, and relevant parts can be referred to the corresponding parts of the semiconductor laser.

It is to be understood that in the description of the present application, the drawings and the description of the embodiments are to be regarded as illustrative in nature and not as restrictive. Like numerals refer to like structures throughout the description of the embodiments. Additionally, the figures may exaggerate the thicknesses of some layers, films, panels, regions, etc. for ease of understanding and ease of description. It will also be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In addition, "on …" means that an element is positioned on or under another element, but does not essentially mean that it is positioned on the upper side of another element according to the direction of gravity.

The terms "upper," "lower," "top," "bottom," "inner," "outer," and the like refer to an orientation or positional relationship relative to an orientation or positional relationship shown in the drawings for ease of description and simplicity of description, but do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present.

It is further noted that, in this document, relational terms such as first and second, and the like may be used solely to distinguish one entity from another entity or from one another, or vice versa, relative to different parts of a device without necessarily requiring or implying any actual such relationship or order between such entities or operations. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in an article or device that comprises the element.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. A semiconductor laser, comprising:

a semiconductor substrate having opposing first and second surfaces;

a functional layer on the first surface;

a laser element located on a side of the functional layer facing away from the semiconductor substrate;

the functional layer is used for increasing the speed of conducting the working heat of the laser element to the semiconductor substrate and reducing the reflection of the semiconductor substrate to the emergent light of the laser element.

2. The semiconductor laser of claim 1, wherein the functional layer comprises a graphene layer comprising a plurality of hollowed-out regions penetrating the graphene layer.

3. The semiconductor laser according to claim 2, wherein the semiconductor substrate is a SiC substrate, and the functional layer is a graphene layer that is thermally converted on a side of the SiC substrate corresponding to the first surface.

4. A semiconductor laser as claimed in claim 2 wherein the graphene layer is a graphene deposited layer.

5. The semiconductor laser of claim 2, wherein a depth of the hollowed-out region is not less than a thickness of the graphene layer.

6. The semiconductor laser according to claim 2, wherein the hollowed-out regions are arranged in an array, and the hollowed-out regions are any one of circular, triangular and rectangular.

7. A semiconductor laser as claimed in claim 2 wherein the graphene layer is less than 10nm thick.

8. A semiconductor laser as claimed in claim 1 wherein the laser element comprises:

the epitaxial layer is positioned on one side, away from the semiconductor substrate, of the functional layer;

the active layer is positioned on one side, away from the functional layer, of the epitaxial layer, and part of the epitaxial layer is exposed out of the active layer;

the first electrode is positioned on one side, away from the epitaxial layer, of the active layer;

and the second electrode is positioned on the surface of the active layer exposed out of the epitaxial layer.

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