VCSEL laser and VCSEL chip

Abstract

The invention discloses a VCSEL (vertical cavity surface emitting laser) and a VCSEL chip. The VCSLE laser comprises at least one oxidation limiting layer and a hole array, the oxidation limiting layer is provided with an oxidation limiting hole, the hole array comprises a plurality of through-flow holes, and at least part of each through-flow hole extends to the oxidation limiting layer; the through-flow holes are distributed in the circumferential direction of the VCSEL laser and are mutually spaced, and the oxidation limiting holes are formed in the hole array; the side walls, facing the oxidation limiting hole, of at least part of the circulation holes are in an arc shape.

Description

Technical Field

[0001] The present application relates to the field of semiconductor lasers, and more specifically to VCSEL lasers and VCSEL chips. Background Art

[0002] VCSEL (Vertical-Cavity Surface-Emitting Laser) is a semiconductor laser that forms a resonant cavity in the vertical direction of the substrate and emits laser in the vertical direction. VCSEL has the characteristics of stable beam quality, single longitudinal mode output, and high photoelectric conversion efficiency. It is widely used in communications, consumer, automotive and other fields.

[0003] The VCSEL laser mainly includes a substrate layer, an N-DBR layer and a P-DBR layer stacked on the substrate layer, an active region sandwiched between the N-DBR layer and the P-DBR layer, and a restriction layer located on the upper side and / or the lower side of the active region. At present, the restriction layer is mainly formed by an oxidation process. Specifically, the structural layer used to form the restriction layer is oxidized, and an oxidizing fluid, such as water vapor, enters the structural layer from the outer edge of the structural layer, and the area close to the outer edge of the structural layer is oxidized to form a restriction area, and the unoxidized area forms a restriction hole.

[0004] In the conventional process, in the process of forming the VCSLE laser, an epitaxial structure is first formed, wherein the epitaxial structure includes, from bottom to top, a substrate layer, an N-DBR structure layer, an active region structure layer, and a P-DBR structure layer; then, a light exit hole is defined; then, the epitaxial structure is etched, and portions of some structural layers in the epitaxial structure surrounding the light exit hole are removed to form a mesa structure; then, the mesa structure is selectively oxidized to form the confinement layer.

[0005] In the process of forming the mesa structure, a whole circle of material around the light exit hole is removed, so that the oxidation hole formed in the subsequent oxidation process of the mesa structure is closer to a circle. However, such a design scheme makes the distance between two adjacent VCSEL lasers larger when forming a VCSEL array including multiple VCSEL lasers, and the arrangement of each VCSEL laser in the VCSEL array is not compact, and the overall volume of the VCSEL array is larger, which does not meet the requirements of device miniaturization.

[0006] The inventor of the present application proposes that only part of the material around the light-emitting hole can be etched to form spaced holes surrounding the light-emitting hole, thereby increasing the design flexibility of the distance between adjacent VCSEL lasers and making the arrangement of each VCSEL laser more compact.

[0007] However, after the oxidizing fluid enters the structural layer used to form the restriction layer, the isotropic diffusion rate and oxidation rate are different, and the holes are spaced apart from each other, making it difficult to control the diffusion range of the oxidizing fluid and the shape of the restriction hole finally formed. The intersection of the oxidizing fluid flowing out of each hole and the oxidation range of the structural layer is prone to form a sharp corner. In this way, the shape of the restriction hole finally formed may deviate greatly from the expected shape of the restriction hole. Summary of the invention

[0008] One advantage of the present application is that it provides a VCSEL laser and a VCSEL chip, wherein the present application provides a scheme for forming an oxidation restriction layer, and the shape of the restriction hole can be controlled by designing the extension direction of the peripheral wall of the hole structure extending to the structural layer used to form the oxidation restriction layer, so that the shape of the restriction hole finally formed is close to the expected shape of the restriction hole.

[0009] Another advantage of the present application is that it provides a VCSEL laser and a VCSEL chip, wherein the present application controls the shape of the limiting hole so that the shape of the limiting hole in the oxidation limiting layer is close to a circle.

[0010] Another advantage of the present application is that it provides a VCSEL laser and a VCSEL chip, wherein the present application reduces the sharpness of the turning corner of the outer edge of the limiting hole in the oxidation limiting layer by controlling the shape of the limiting hole, thereby improving the reliability of the VCSEL laser.

[0011] In order to achieve at least one of the above advantages or other advantages and purposes, according to one aspect of the present application, a VCSEL laser is provided, comprising:

[0012] at least one oxidation limiting layer, the oxidation limiting layer having an oxidation limiting pore; and

[0013] a hole array, the hole array comprising a plurality of flow holes, each of the flow holes at least partially extending to the oxidation limiting layer; the plurality of flow holes are arranged along the circumference of the VCSEL laser and are spaced apart from each other, and the oxidation limiting hole is formed in the hole array;

[0014] Among the plurality of flow holes, at least some of the flow holes have arc-shaped side walls facing the oxidation limiting hole.

[0015] In some embodiments, the hole array includes a plurality of first flow holes, the cross section of the first flow holes is semicircular, and the central angle corresponding to the first flow holes is less than 180 degrees.

[0016] In some embodiments, the plurality of first flow holes form a first group of holes, and the plurality of first flow holes are centrally symmetrically distributed about a center point of the first group of holes.

[0017] In some embodiments, the number of the first flow holes is greater than or equal to one.

[0018] In some embodiments, the hole array includes four of the first flow holes.

[0019] In some embodiments, the hole array includes a plurality of second flow holes, and the cross-section of the second flow holes is rectangular.

[0020] In some embodiments, a plurality of the second flow holes form a second group of holes, and the second flow holes are centrally symmetrically distributed about a center point of the second group of holes.

[0021] In some embodiments, the distances between every two adjacent flow holes are equal.

[0022] According to another aspect of the present application, a VCSEL chip is provided, comprising:

[0023] At least two VCSEL lasers as described above.

[0024] In some embodiments, every two adjacent VCSEL lasers share at least one flow hole.

[0025] Further objectives and advantages of the present application will be fully reflected through understanding of the following description and drawings.

[0026] These and other objects, features and advantages of the present application are fully reflected in the following detailed description, drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] These and / or other aspects and advantages of the present application will become clearer and easier to understand from the following detailed description of the embodiments of the present application in conjunction with the accompanying drawings, in which:

[0028] Figure 1 A schematic diagram of an implementation of a hole array of a VCSEL laser according to an embodiment of the present application is illustrated.

[0029] Figure 2 A schematic diagram of an implementation of a first flow hole of a hole array of a VCSEL laser according to an embodiment of the present application is illustrated.

[0030] Figure 3 A schematic diagram of another implementation of a hole array of a VCSEL laser according to an embodiment of the present application is illustrated.

[0031] Figure 4 A schematic diagram of another implementation of a hole array of a VCSEL laser according to an embodiment of the present application is illustrated.

[0032] Figure 5 A schematic diagram of another implementation of a hole array of a VCSEL laser according to an embodiment of the present application is illustrated.

[0033] Figure 6 A schematic diagram of another implementation of a hole array of a VCSEL laser according to an embodiment of the present application is illustrated. DETAILED DESCRIPTION

[0034] The terms and words used in the following specification and claims are not limited to the literal meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present application. Therefore, it will be apparent to those skilled in the art that the following description of various embodiments of the present application is provided for illustration purposes only and not for the purpose of limiting the present application as defined by the appended claims and their equivalents.

[0035] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0036] Although ordinals such as "first," "second," and the like will be used to describe various components, those components are not limited herein. The term is used only to distinguish one component from another. For example, a first component may be referred to as a second component, and likewise, a second component may be referred to as a first component without departing from the teachings of the present application. The term "and / or" as used herein includes any and all combinations of one or more associated listed items.

[0037] The terms used herein are only used for the purpose of describing various embodiments and are not intended to be limiting. As used herein, singular forms are intended to also include plural forms, unless the context clearly indicates an exception. In addition, it will be understood that the terms "including" and / or "having" when used in this specification specify the presence of the described features, numbers, steps, operations, components, elements or combinations thereof, without excluding the presence or addition of one or more other features, numbers, steps, operations, components, elements or groups thereof.

[0038] Application Overview

[0039] As mentioned above, currently, the limiting layer is mainly formed by an oxidation process. Specifically, the structural layer used to form the limiting layer is oxidized, and an oxidizing fluid, such as water vapor, enters the structural layer from the outer edge of the structural layer, and the area near the outer edge of the structural layer is oxidized to form a limiting area, and the unoxidized area forms a limiting hole.

[0040] In the traditional process, the mesa structure is selectively oxidized to form the restriction layer. In the process of forming the mesa structure, a whole circle of material around the light exit hole is removed, so that the oxidation hole formed in the subsequent oxidation of the mesa structure is closer to a circle. However, such a design scheme makes the distance between two adjacent VCSEL lasers larger when forming a VCSEL array including multiple VCSEL lasers, and the arrangement of each VCSEL laser in the VCSEL array is not compact, and the overall volume of the VCSEL array is larger, which does not meet the requirements of device miniaturization.

[0041] The inventor of the present application proposes that only part of the material around the light-emitting hole can be etched to form spaced holes surrounding the light-emitting hole, thereby increasing the design flexibility of the distance between adjacent VCSEL lasers and making the arrangement of each VCSEL laser more compact.

[0042] However, after the oxidizing fluid enters the structural layer used to form the restriction layer, the isotropic diffusion rate and oxidation rate are different, and the holes are spaced apart from each other, making it difficult to control the diffusion range of the oxidizing fluid and the shape of the restriction hole finally formed. The intersection of the oxidizing fluid flowing out of each hole and the oxidation range of the structural layer is prone to form a sharp corner. In this way, the shape of the restriction hole finally formed may deviate greatly from the expected shape of the restriction hole.

[0043] The inventors of the present application noticed that the peripheral wall of the hole has a guiding effect on the oxidizing fluid, so that the oxidizing fluid flows and diffuses inward from the outer edge of the structural layer along the extension direction of the peripheral wall of the hole, and impregnates the structural layer used to form the restriction layer, and oxidizes the structural layer used to form the restriction layer along a specific direction. In this way, a restriction hole is formed in the hole structure.

[0044] Based on this, the inventors of the present application proposed to control the flow direction of the oxidation fluid by designing the extension direction of the peripheral wall of the hole extending to the structural layer used to form the oxidation restriction layer, thereby controlling the shape of the restriction hole finally formed.

[0045] After introducing the basic principles of the present application, various non-limiting embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0046] Schematic VCSEL laser

[0047] like Figures 1 to 6As shown, a VCSEL laser according to an embodiment of the present application is illustrated. The VCSEL laser has a multi-layer structure, mainly including a substrate layer, an N-DBR layer, a P-DBR layer, an active region sandwiched between the N-DBR layer and the P-DBR layer, and an oxidation restriction layer located on the upper side of the active region and / or the lower side of the active region, wherein the oxidation restriction layer has an oxidation restriction hole 101.

[0048] In the embodiment of the present application, the VCSEL laser further comprises a hole array 10, wherein the hole array 10 comprises a plurality of flow holes, each of which at least partially extends to the oxidation restriction layer. Specifically, the flow holes extend from the upper surface of the VCSEL laser to below the active region, that is, below the bottom surface of the active region.

[0049] For example, when the substrate layer, the N-DBR layer, the active area, the oxidation restriction layer and the P-DBR layer are arranged from bottom to top, the flow hole extends from the P-DBR layer to the N-DBR layer below the active area, and the flow hole passes through the oxidation restriction layer; for another example, when the substrate layer, the P-DBR layer, the active area, the oxidation restriction layer and the N-DBR layer are arranged from bottom to top, the flow hole extends from the N-DBR layer to the P-DBR layer below the active area, and the flow hole passes through the oxidation restriction layer.

[0050] The plurality of flow holes are arranged along the circumference of the VCSEL laser and are spaced from each other, and the oxidation limiting hole 101 is formed in the hole array 10 enclosed by the plurality of flow holes. In the process of forming the oxidation limiting layer, an oxidation fluid is introduced into the flow hole, wherein the flow hole is located at the outer portion of the structural layer used to form the oxidation limiting layer; the oxidation fluid enters the interior of the structural layer used to form the oxidation limiting layer from the flow hole; the portion of the structural layer used to form the oxidation limiting layer oxidized by the oxidation fluid forms a restriction area, and the portion of the interior that is not oxidized by the oxidation fluid forms the oxidation limiting hole 101.

[0051] It is worth mentioning that the peripheral wall of the flow hole has a guiding effect on the oxidation fluid. In the process of forming the oxidation restriction layer, the oxidation fluid flows along the extension direction of the peripheral wall of the flow hole and diffuses to the surroundings. Accordingly, in the embodiment of the present application, the flow direction of the oxidation fluid is regulated by designing the extension direction of the peripheral wall of the flow hole, thereby regulating the shape of the oxidation restriction hole 101 finally formed.

[0052] It is also worth mentioning that when a turning angle appears at the outer edge of the oxidation limiting hole 101 and the sharpness of the turning angle is large, the number of currents gathered at the intersection is large, resulting in a current density at the intersection that is much higher than the surrounding area, resulting in a higher local thermal effect and reduced reliability of the VCSEL laser. Therefore, it is expected that the oxidation limiting hole 101 finally formed is close to a circle, so that the sharpness of the turning angle of the outer edge of the oxidation limiting hole 101 in the oxidation limiting layer is reduced to improve the reliability of the VCSEL laser. The present application proposes to design the sidewalls of at least some of the plurality of flow holes facing the oxidation limiting hole 101 to be arc-shaped.

[0053] The shapes of other side walls of the flow hole with the side wall designed to be arc-shaped facing the oxidation limiting hole 101 are not limited by the present application. Accordingly, the overall shape of the flow hole with the side wall designed to be arc-shaped facing the oxidation limiting hole 101 is not limited by the present application.

[0054] In some embodiments of the present application, Figures 1 to 4 As shown, the overall shape of the flow hole with the arc-shaped sidewall facing the oxidation limiting hole 101 is a semicircular ring. Accordingly, in some embodiments of the present application, the hole array 10 includes a plurality of first flow holes 11, and the cross section of the first flow holes 11 is a semicircular ring, wherein the center angle of the first flow holes 11 is less than 180 degrees. Here, the cross section of the first flow hole 11 refers to: a plane perpendicular to the height direction of the VCSEL laser.

[0055] Correspondingly, the first flow hole 11 has a first side wall 111, a second side wall 112, a third side wall 113 and a fourth side wall 114; wherein the first side wall 111 faces the oxidation limiting hole 101 and is arc-shaped; the second side wall 112 is opposite to the first side wall 111, is arc-shaped, and has the same bending direction as the first side wall 111; the second side wall 112 is located outside the first side wall 111, and is longer than the first side wall 111. Preferably, the curvature of the first side wall 111 is the same as that of the second side wall 112. The third side wall 113 extends between one end of the first side wall 111 and one end of the second side wall 112, and the fourth side wall 114 extends between the other end of the first side wall 111 and the other end of the second side wall 112, and the third side wall 113 is opposite to the fourth side wall 114. Preferably, a first central axis L1 is formed between the third side wall 113 and the fourth side wall 114 , and the first circulation holes 11 are symmetrical about the first central axis L1 .

[0056] It should be understood that the cross-sectional shape of the first circulation hole 11 can be designed to be other shapes. For example, in some other embodiments of the present application, the cross-sectional shape of the first circulation hole 11 is similar to the hyperbolic figure corresponding to the hyperbolic function. Specifically, the first circulation hole 11 has a first side wall 111, a second side wall 112, a third side wall 113 and a fourth side wall 114; wherein the first side wall 111 faces the oxidation limiting hole 101 and is arc-shaped; the second side wall 112 is opposite to the first side wall 111, is arc-shaped, and is opposite to the bending direction of the first side wall 111; the second side wall 112 is located on the outside of the first side wall 111, and its length is longer than the length of the first side wall 111. Preferably, the curvature of the first side wall 111 is the same as the curvature of the second side wall 112. The third side wall 113 extends between one end of the first side wall 111 and one end of the second side wall 112 , the fourth side wall 114 extends between the other end of the first side wall 111 and the other end of the second side wall 112 , and the third side wall 113 is opposite to the fourth side wall 114 .

[0057] The first plurality of circulation holes 11 form a first group of holes. Preferably, the first plurality of circulation holes 11 are distributed symmetrically about the center point O1 of the first group of holes. Specifically, the center point O1 of the first group of holes refers to the geometric center point of a pattern formed by connecting the geometric center points of all the first circulation holes 11.

[0058] It is worth mentioning that the shapes of the flow holes in the hole array 10 can be all consistent, that is, the shapes of the cross sections of all the flow holes are the same; the shapes of the cross sections of the flow holes in the hole array 10 can also be partially consistent.

[0059] In some embodiments of the present application, the cross-sectional shapes of all the flow holes in the hole array 10 are the same, such as Figure 4 and Figure 6 As shown, the side wall of each of the flow holes facing the oxidation limiting hole 101 is arc-shaped.

[0060] In some other embodiments of the present application, the hole array 10 includes two types of flow holes with different shapes, that is, a plurality of first flow holes 11 and a plurality of second flow holes 12, wherein the cross-sectional shapes of the plurality of first flow holes 11 are consistent, and the cross-sectional shapes of the plurality of second flow holes 12 are consistent, such as Figure 1 , Figure 3 and Figure 5 The side wall of the first flow hole 11 facing the oxidation limiting hole 101 is arc-shaped, and the cross-section of the first flow hole 11 is in a semicircular ring shape, or other shapes; the cross-section of the second flow hole 12 is in a rectangular shape (such as Figure 1 and Figure 5 ), or other shapes, such as a trapezoid (as shown Figure 3 The plurality of second flow holes 12 form a second group of holes, and the second flow holes 12 are distributed symmetrically about the center point O2 of the second group of holes. Specifically, the center point O2 of the second group of holes refers to the geometric center point of a pattern formed by connecting the geometric center points of all the second flow holes 12. The center point O1 of the first group of holes coincides with the center point O2 of the second group of holes.

[0061] The number of the first flow holes 11 and the number of the second flow holes are not limited by the present application. In some embodiments of the present application, the number of the first flow holes 11 is greater than or equal to 1, and the number of the second flow holes 12 is greater than or equal to 1. For example, in one embodiment of the present application, the number of the first flow holes 11 is 4, and the number of the second flow holes 12 is 2, wherein two of the first flow holes 11 are distributed on the first side of the VCSEL laser, the other two of the first flow holes 11 are distributed on the second side of the VCSEL laser, one of the second flow holes 12 is distributed on the third side of the VCSEL laser, and the other third flow hole is distributed on the fourth side of the VCSEL laser; the first side of the VCSEL laser is opposite to the second side, the third side of the VCSEL laser is opposite to the fourth side, the third side of the VCSEL laser is located between the first side and the second side of the VCSEL laser, and the fourth side of the VCSEL laser is located between the first side and the second side of the VCSEL laser.

[0062] In the embodiment of the present application, preferably, the distance between each two adjacent flow holes is equal. The distance between each two adjacent flow holes should be designed according to the requirements, so that the oxidation ranges 102 of the oxidation fluid entering the structural layer for forming the oxidation restriction layer from each flow hole overlap with each other and enclose the oxidation restriction hole 101 of the expected shape and expected size.

[0063] Accordingly, the present application proposes a VCSEL chip, which includes at least two VCSEL lasers as described above. Optionally, at least two of the VCSEL lasers share at least one flow hole, so that the arrangement between the VCSEL lasers is more compact.

[0064] In one embodiment of the present application, the hole array 10 includes a plurality of first flow holes 11 and a plurality of second flow holes 12, wherein the cross-sectional shapes of the plurality of first flow holes 11 are consistent, and the cross-sectional shapes of the plurality of second flow holes 12 are consistent. The sidewall of the first flow hole 11 facing the oxidation limiting hole 101 is arc-shaped, and the cross-sectional shape of the second flow hole 12 is rectangular. Every two adjacent VCSEL lasers share one first flow hole 11 or one second flow hole 12, that is, in the hole array 10, at least one first flow hole 11 or at least one second flow hole 12 forms a common flow hole.

[0065] In summary, the VCSEL laser and VCSEL chip based on the embodiments of the present application are explained, and the present application provides a scheme for forming an oxidation restriction layer, which can control the shape of the restriction hole by designing the extension direction of the peripheral wall of the hole structure extending to the structural layer used to form the oxidation restriction layer, so that the shape of the restriction hole finally formed is close to the expected shape of the restriction hole.

[0066] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

Claims

1. A VCSEL laser, characterized in that: include: at least one oxidation restriction layer, the oxidation restriction layer having an oxidation restriction hole; and a hole array, the hole array comprising a plurality of flow holes, each of the flow holes at least partially extending to the oxidation limiting layer; the plurality of flow holes are arranged along the circumference of the VCSEL laser and are spaced apart from each other, and the oxidation limiting hole is formed in the hole array; Among the plurality of flow holes, at least some of the flow holes have arc-shaped side walls facing the oxidation limiting hole.

2. The VCSEL laser according to claim 1, wherein: The hole array includes a plurality of first flow holes, the cross section of the first flow holes is semicircular, and the central angle corresponding to the first flow holes is less than 180 degrees.

3. The VCSEL laser according to claim 2, wherein: The plurality of first flow holes form a first group of holes, and the plurality of first flow holes are centrally symmetrically distributed about a center point of the first group of holes.

4. The VCSEL laser according to claim 2, wherein: The number of the first flow holes is greater than or equal to one.

5. The VCSEL laser according to claim 4, wherein: The hole array includes four of the first flow holes.

6. The VCSEL laser according to claim 2, wherein: The hole array includes a plurality of second flow holes, and the cross-section of the second flow holes is rectangular.

7. The VCSEL laser according to claim 6, wherein: A plurality of the second flow holes form a second group of holes, and the second flow holes are centrally symmetrically distributed about a center point of the second group of holes.

8. The VCSEL laser according to claim 1, wherein: The distance between each two adjacent flow holes is equal.

9. A VCSEL chip, characterized in that: include: At least a VCSEL laser as claimed in any one of claims 1 to 8.

10. The VCSEL chip according to claim 9, wherein: At least two of the VCSEL lasers share a common flow hole.

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