Densely packed vertical cavity surface emitting lasers

Abstract

The present invention provides a tightly packed vertical cavity surface emitting laser (VCSEL), comprising: an isolation layer comprising a polygonal main portion and additional portions disposed at each corner of the polygon; a metal layer having a plurality of spaced-apart P-type contact electrodes, each disposed at different corners of the polygonal main portion and the additional portions at the corresponding corners, with each P-type contact electrode extending away from the center of the main portion; a dielectric via layer disposed on a side of the P-type contact electrode away from the main portion, the dielectric via layer having a plurality of dielectric vias, the plurality of dielectric vias being disposed in a one-to-one correspondence with the plurality of P-type contact electrodes, such that at least a portion of the P-type contact electrodes is exposed; and a plurality of oxidation trenches, at least a portion of the oxidation trenches being located between adjacent P-type contact electrodes. The present invention solves the problem of prior art VCSELs that prevents miniaturization.

Description

Technical Field

[0001] The present invention relates to the technical field of laser equipment, and in particular to a closely arranged vertical cavity surface emitting laser. Background Art

[0002] The table structure of a conventional VCSEL (vertical cavity surface emitting laser) is generally circular, and the advantages of a circular table are quite obvious, such as the uniformity of current injection and the perfect circularity of the oxide hole diameter. However, with the introduction of ion implantation and trench structures, this circular table structure is no longer necessary. With the rapid development of VCSEL technology in recent years, its performance has been greatly improved. However, under the fierce market competition, chip size and cost are also the focus of consideration for product-side customers. In addition, with the entry of VCSEL into the LiDAR market, the demand for higher power density is also one of the problems that VCSEL urgently needs to overcome. Therefore, while ensuring consistent performance, a miniaturized structure is bound to play a good role in improvement.

[0003] That is to say, the VCSEL in the prior art has the problem of not being able to be miniaturized. Summary of the Invention

[0004] The main purpose of the present invention is to provide a compact vertical cavity surface emitting laser to solve the problem that the compact vertical cavity surface emitting laser in the prior art cannot be miniaturized.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a tightly arranged vertical cavity surface emitting laser is provided, comprising: an isolation layer, the isolation layer comprising a polygonal main body and additional portions arranged at each corner of the polygon; a metal layer, the metal layer having a plurality of spaced-apart P-type contact electrodes, the plurality of P-type contact electrodes being respectively arranged at different corners of the polygonal main body and the additional portions of the corresponding corners, and the P-type contact electrodes all extend in a direction away from the center of the main body; a dielectric through-hole layer, the dielectric through-hole layer being arranged on a side of the P-type contact electrode away from the main body, the dielectric through-hole layer having a plurality of dielectric through-holes, the plurality of dielectric through-holes being arranged in one-to-one correspondence with the plurality of P-type contact electrodes, so that at least a portion of the P-type contact electrode is exposed; and a plurality of oxidation trenches, at least a portion of the oxidation trenches being located between adjacent P-type contact electrodes.

[0006] Furthermore, the main body is a regular polygon.

[0007] Furthermore, the P-type contact electrode includes a connecting portion and a protruding portion, wherein the connecting portion is connected to the main body portion and is located inside the outer periphery of the main body portion.

[0008] Furthermore, the distances between the side edges of each connecting portion away from the protruding portion and the center of the main body portion are all equal.

[0009] Furthermore, a side edge of the connecting portion away from the protruding portion is arc-shaped.

[0010] Furthermore, a side edge of the connecting portion that is away from the center of the main body portion is flush with the outer periphery of the main body portion.

[0011] Furthermore, the connecting portion has connecting wings located on both sides of the protruding portion to increase the connection area between the connecting portion and the isolation layer.

[0012] Furthermore, the dielectric through hole corresponds to the protruding portion, so that the protruding portion is exposed.

[0013] Furthermore, the main body parts are multiple and spaced apart, and the three additional parts close to each other on three adjacent main body parts are integrally formed.

[0014] Furthermore, there are multiple main body parts and they are arranged at intervals, and three adjacent main body parts share a P-type contact electrode, and two adjacent main body parts share an oxidation trench.

[0015] Furthermore, the oxidation trench is a polygonal structure, and at least one side of the polygonal structure is parallel to a side of the main body.

[0016] Furthermore, the sides of the polygonal main body include straight sides and / or arc sides.

[0017] By applying the technical solution of the present invention, a tightly arranged vertical cavity surface emitting laser includes an isolation layer, a metal layer, a dielectric through-hole layer and a plurality of oxidation trenches, wherein the isolation layer includes a polygonal main portion and an additional portion arranged at each corner of the polygon; the metal layer has a plurality of spaced-apart P-type contact electrodes, wherein the plurality of P-type contact electrodes are respectively arranged at different corners of the polygonal main portion and on the additional portions of the corresponding corners, and the P-type contact electrodes all extend in a direction away from the center of the main portion; the dielectric through-hole layer arranges the P-type contact electrode on a side away from the isolation layer, and the dielectric through-hole layer has a plurality of dielectric through-holes, wherein the plurality of dielectric through-holes are arranged in a one-to-one correspondence with the plurality of P-type contact electrodes, so that at least a portion of the P-type contact electrode is exposed; and at least a portion of the oxidation trench is located between adjacent P-type contact electrodes.

[0018] By setting the main body of the isolation layer into a polygonal structure, and multiple P-type contact electrodes are set at the corners of the polygonal main body and on the additional part, the area of ​​a single VCSEL unit can be effectively reduced, which is conducive to the miniaturization of tightly arranged vertical cavity surface emitting lasers. The spacing of multiple P-type contact electrodes enables the P-type contact electrodes to achieve current injection similar to that of a ring electrode without having to be connected together, and the spacing of multiple P-type contact electrodes ensures the possibility of reducing the area of ​​the main body. At the same time, it is conducive to the miniaturization of tightly arranged vertical cavity surface emitting lasers. The dielectric through-holes are set corresponding to the P-type contact electrodes so that the metallization contacts the P-type contact electrodes via the dielectric through-holes. The setting of the oxidation groove can facilitate the oxidation of part of the structure of the tightly arranged vertical cavity surface emitting laser, so that the tightly arranged vertical cavity surface emitting laser can emit laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 shows a schematic structural diagram of a VCSEL unit according to embodiment 1 of the present invention; and

[0021] Figure 2 A schematic diagram showing the size relationship between a polygonal main body portion and a circular main body portion according to the first embodiment of the present invention is shown;

[0022] Figure 3 FIG2 shows a schematic structural diagram of a VCSEL array according to a first embodiment of the present invention.

[0023] The above drawings include the following reference numerals:

[0024] 10. Isolation layer; 11. Main body; 12. Additional portion; 20. P-type contact electrode; 21. Connecting portion; 22. Extending portion; 23. Connecting wing; 30. Dielectric through hole; 40. Oxidation trench; 50. Oxidation aperture. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0027] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity direction; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0028] In order to solve the problem that closely arranged vertical cavity surface emitting lasers in the prior art cannot be miniaturized, the present invention provides a closely arranged vertical cavity surface emitting laser.

[0029] like Figures 1 to 3 As shown, the tightly arranged vertical cavity surface emitting laser includes an isolation layer 10, a metal layer, a dielectric through-hole layer and a plurality of oxidation trenches 40, the isolation layer 10 includes a polygonal main body 11 and an additional portion 12 arranged at each corner of the polygon; the metal layer has a plurality of spaced P-type contact electrodes 20, the plurality of P-type contact electrodes 20 are respectively arranged at different corners of the polygonal main body 11 and on the additional portions 12 of the corresponding corners, and the P-type contact electrodes 20 all extend in a direction away from the center of the main body 11; the dielectric through-hole layer is provided with a side of the P-type contact electrode away from the isolation layer 10, the dielectric through-hole layer has a plurality of dielectric through-holes 30, the plurality of dielectric through-holes 30 are arranged one-to-one with the plurality of P-type contact electrodes 20, so that at least a portion of the P-type contact electrode 20 is exposed; at least a portion of the oxidation trench 40 is located between adjacent P-type contact electrodes 20.

[0030] By setting the main body 11 of the isolation layer 10 into a polygonal structure, and multiple P-type contact electrodes 20 are set at the corners of the polygonal main body 11 and on the additional part 12, the area of ​​a single VCSEL unit can be effectively reduced, which is conducive to the miniaturization of tightly arranged vertical cavity surface emitting lasers. The multiple P-type contact electrodes 20 are arranged at intervals, so that the P-type contact electrodes 20 do not need to be connected together to achieve current injection similar to a ring electrode, and the multiple P-type contact electrodes 20 are arranged at intervals to ensure the possibility of reducing the area of ​​the main body 11. At the same time, it is conducive to the miniaturization of tightly arranged vertical cavity surface emitting lasers. The dielectric through hole 30 is arranged corresponding to the P-type contact electrode 20 so that the metallization contacts the P-type contact electrode 20 via the dielectric through hole 30. The setting of the oxidation groove 40 can facilitate the oxidation of part of the structure of the tightly arranged vertical cavity surface emitting laser, so that the tightly arranged vertical cavity surface emitting laser can emit laser.

[0031] The oxidation trench 40 is polygonal and located outside the polygonal side of the main mesa portion 11 to allow oxidizing gas to enter and form the oxidation aperture 50. The shape and size of the oxidation trench 40 directly affect the profile of the oxidation aperture 50.

[0032] It should be noted that the sides of the polygonal main body 11 may be straight sides only, arc sides only, or a combination of straight sides and arc sides.

[0033] When the sides of the polygonal main portion 11 are arcuate, the center of the arcuate is located outside the main portion 11. In other words, the arcuate sides of the polygonal main portion 11 are concave arcuate sides, forming multiple corners. The curvature radii of the multiple arcuate sides of the polygonal main portion 11 can be the same or different.

[0034] Preferably, the main body 11 of the isolation layer 10 is a regular polygon. This configuration facilitates control of the position and contact area of ​​the P-type contact electrode 20, facilitating current injection. When the polygon has arc edges, a regular polygon means that the radius of curvature and the curvature of the multiple arc edges are the same.

[0035] like Figure 1 As shown, the P-type contact electrode 20 includes a connecting portion 21 and an extending portion 22. The connecting portion 21 is connected to the main portion 11 and is located inside the outer periphery of the main portion 11. The provision of the extending portion 22 does not affect the oxidation of the partial structure located inside the connecting portion 21. While ensuring the area of ​​the P-type contact electrode 20, the area occupied by the connecting portion 21 on the main portion 11 is minimized. The extending portion 22 is located on the additional portion 12, while the connecting portion 21 is located on the main portion 11.

[0036] like Figure 1 As shown, the distance between the side of each connecting portion 21 away from the extension portion 22 and the center of the main body portion 11 is equal. This arrangement ensures that the distance between each P-type contact electrode 20 and the center of the main body portion 11 is the same, ensuring that when current is subsequently injected, the P-type contact electrode 20 at each position has the same impact on the central emitter region.

[0037] like Figure 1 As shown, the side of the connecting portion 21 away from the protruding portion 22 is arc-shaped. The distance from each position of the side of the connecting portion 21 away from the protruding portion 22 to the center of the main body 11 is the same. In other words, the inner side edges of the connecting portions 21 of the multiple P-type contact electrodes 20 in this application are all on a single circumference.

[0038] like Figure 1 As shown, the side of the connecting portion 21 facing away from the center of the main body 11 is flush with or partially covers the outer periphery of the main body 11. This arrangement facilitates the production of tightly packed vertical cavity surface emitting lasers and helps ensure the performance of the P-type contact electrode 20.

[0039] like Figure 1As shown, the connecting portion 21 has connecting wings 23 on both sides of the protruding portion 22 to increase the connection area between the connecting portion 21 and the isolation layer 10. The provision of the connecting wings 23 increases the connection area between the connecting portion 21 and the isolation layer 10 to ensure the effect of current injection.

[0040] The isolation layer 10 may have a plurality of additional portions 12 . The additional portions 12 are extended from the main portion 11 , and the extension portions 22 of the P-type contact electrodes 20 are located on the additional portions 12 .

[0041] like Figure 1 As shown, dielectric via 30 corresponds to extension 22, leaving extension 22 partially exposed. In other words, dielectric via 30 is located within the region of P-type contact electrode 20 to ensure that current can be injected into the metal layer after polarization while preventing it from leaking outside the area covered by isolation layer 10. Dielectric via 30 can have any shape, including rectangular and circular, that can be contained within the P-type contact electrode 20.

[0042] It should be noted that the aforementioned isolation layer 10, P-type contact electrode 20, and multiple outer oxide trenches 40 collectively constitute a VCSEL unit. Multiple VCSEL units are arranged to form a VCSEL array. The shared P-type contact electrode 20 and the structure of multiple P-type contact electrodes 20 integrally formed are both VCSEL arrays.

[0043] like Figure 3 As shown, multiple main bodies 11 are spaced apart, and three adjacent additional portions 12 on three adjacent main bodies 11 are interconnected and integrally formed. In this embodiment, the closely spaced vertical cavity surface emitting lasers are arranged in an array. Because the main bodies 11 are polygonal in structure, the three main bodies 11 can be very close to each other, allowing the three P-type contact electrodes 20 on the three isolation layers 10 to be integrally formed. Furthermore, the three integrally formed P-type contact electrodes 20 can be shared by all three isolation layers 10. In this embodiment, two adjacent main bodies 11 share a common oxidation trench 40.

[0044] like Figure 3 As shown, multiple body portions 11 are spaced apart, with three adjacent body portions 11 sharing a P-type contact electrode 20, and two adjacent body portions 11 sharing an oxidation trench 40. In this embodiment, the shared P-type contact electrode 20 has a central electrode body portion and a connecting pin extending from the electrode body portion, with the connecting pin connecting to the body portion 11. In this embodiment, the dielectric through-hole 30 is also shared.

[0045] Multiple VCSEL units are arranged in a certain manner to ensure that the oxidation trenches 40 achieve maximum overlap (close to 100%, the trapezoid can be adjusted to a rectangle, including a rectangle formed by the upper and lower long sides or short sides of the trapezoid). This overlapping method has the highest space utilization rate and is the most dense without affecting performance. The middle part of the overlapping oxidation trenches 40 is then designed as an electrode Pad, and the P-type contact electrodes 20 on the three adjacent main bodies 11 are connected to the center Pad. Then, a dielectric through-hole 30 is made on the Pad. The shape of the dielectric through-hole 30 includes any shape such as rectangle, circle, etc. contained within the above-mentioned electrode.

[0046] like Figure 1 and Figure 3 As shown, the oxidation trench 40 is a polygonal structure, at least one side of which is parallel to the side of the main body 11. This arrangement minimizes the distance between the oxidation trench 40 and the main body 11, allowing multiple main bodies 11 to be closely arranged while ensuring the performance of one main body 11.

[0047] It should be noted that the isolation layer 10 may be a mesa layer formed by digging a mesa, or may be a current channel formed by ion implantation in other areas.

[0048] Example 1

[0049] exist Figure 1 In the embodiment shown, the sides of the polygonal main body 11 are straight sides, and the main body 11 is a regular polygon.

[0050] The following description will be made by taking the case where the table main body in the figure is a regular hexagon as an example.

[0051] The hexagonal dimensions of the mesa-shaped main body 11 are inscribed within a circular hexagon. Six extensions 12 extend from the six corners of the main body 11 to accommodate the P-type contact electrode 20. The extensions 22 of the P-type contact electrode 20 can be rectangular, trapezoidal, or other shapes. This arrangement further reduces the area of ​​the main body 11 compared to the circular shape without affecting the performance of closely spaced VCSELs, allowing for a more compact arrangement of multiple main bodies 11.

[0052] The annular electrode corresponding to the circular main body is replaced with a segmented P-type contact electrode 20 extending from the six corners. The P-type contact electrode 20 can cover the inner and outer areas of the main body 11, and ensure that the inner diameter formed by all P-type contact electrodes 20 is the same as the inner diameter parameter of the annular electrode, effectively ensuring the performance of the tightly arranged vertical cavity surface emitting laser, and also reducing the size of the main body 11, so that the multiple main bodies 11 are arranged more closely.

[0053] It should be noted that the P-type contact electrode 20 is designed as a segmented structure here mainly considering the effective current injection part overlapping with the isolation layer 10. The actual shape of the P-type contact electrode 20 is not limited to this, and can exceed the limitations of the isolation layer 10 and the expansion area of ​​the isolation layer 10, that is, other electrode shapes including these effective overlapping parts should also be within the protection range.

[0054] The outer portions of the polygonal main body 11 of the oxidation trench 40 are used to allow oxidizing gas to enter, forming the oxidation aperture 50. The shape and size of the oxidation trench 40 directly affect the profile of the oxidation aperture 50. For example, in this embodiment, the six trapezoidal oxidation trenches 40 will make the oxidation aperture 50 more hexagonal. Increasing the inward curvature of the inner edges will gradually transform the oxidation aperture into a circular shape.

[0055] Quantitative analysis of overall size Figure 2 As shown, the unfilled area represents the structure of the circular main body and its corresponding oxidation trench, and the filled area represents the structure of the hexagonal main body and the oxidation trench corresponding to one side. Spacing 1 is the distance between the inner side of the oxidation trench of the hexagonal main body and the hexagonal main body, and Spacing 2 is the distance between the inner side of the oxidation trench of the circular main body and the circular main body. Here, it is necessary to ensure that the widths of the two oxidation trenches are the same, and to ensure that Spacing 1 and Spacing 2 are equal, then the overall structure is reduced in size by approximately 13% of the circular main body. In addition, the overall size of the inner side of the oxidation trench of the hexagonal main body is still smaller than that of the circular table.

[0056] d' is the distance between two straight sides of the hexagonal main body, and d is the diameter of the circular main body, and the reduced dimension: d-d' is approximately equal to 13% of d.

[0057] Example 2

[0058] The difference from the first embodiment is that the shape of the main body 11 is different.

[0059] This embodiment builds upon the regular polygonal structure of Example 1 by inscribing a plurality of arcuate edges to form a main body 11. The multiple arcuate edges of the polygonal main body 11 have the same radius of curvature and arc, and their centers are located outside the main body 11. In other words, the arcuate edges of the polygonal main body 11 are concave, forming multiple corners. This further reduces the area of ​​the main body 11 compared to Example 1.

[0060] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0061] 1. By adjusting the shape of the main body 11, a polygonal main body 11 is formed, thereby reducing the overall size of the VCSEL unit and ensuring that the performance of the VCSE L unit is close.

[0062] 2. Miniaturized VCSEL units can increase the output of a single wafer, thereby reducing the average cost;

[0063] 3. Design miniaturized VCSEL units so that VCSEL arrays of the same size can accommodate more VCSEL points, thereby improving power density and adapting to more and more demanding application scenarios.

[0064] Obviously, the embodiments described above are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0065] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, tasks, devices, components and / or combinations thereof.

[0066] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0067] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A densely packed vertical cavity surface emitting laser, characterized in that: include: An isolation layer (10), the isolation layer (10) comprising a polygonal main portion (11) and additional portions (12) arranged at each corner of the polygon; a metal layer, the metal layer having a plurality of spaced-apart P-type contact electrodes (20), the plurality of P-type contact electrodes (20) being respectively arranged on different corners of the polygonal main body (11) and the additional portions (12) corresponding to the corners, and the P-type contact electrodes (20) all extending in a direction away from the center of the main body (11); a dielectric through-hole layer, the dielectric through-hole layer being arranged on a side of the P-type contact electrode away from the main body (11), the dielectric through-hole layer having a plurality of dielectric through-holes (30), the plurality of dielectric through-holes (30) being arranged in a one-to-one correspondence with the plurality of P-type contact electrodes (20), so that at least a portion of the P-type contact electrode (20) is exposed; a plurality of oxidation trenches (40), at least a portion of the oxidation trenches (40) being located between adjacent P-type contact electrodes (20); The P-type contact electrode (20) comprises a connecting portion (21) and a protruding portion (22), wherein the connecting portion (21) is connected to the main body (11) and is located inside the outer periphery of the main body (11).

2. The closely packed vertical cavity surface emitting laser according to claim 1, characterized in that: The main body (11) is a regular polygon.

3. The closely packed vertical cavity surface emitting laser according to claim 1, characterized in that: The distances between the side edges of each connecting portion (21) away from the protruding portion (22) and the center of the main body (11) are all equal.

4. The closely packed vertical cavity surface emitting laser according to claim 3, characterized in that: The side of the connecting portion (21) away from the protruding portion (22) is arc-shaped.

5. The compact vertical cavity surface emitting laser according to claim 1, characterized in that: The side edge of the connecting portion (21) that is away from the center of the main body portion (11) is flush with the outer periphery of the main body portion (11).

6. The closely packed vertical cavity surface emitting laser according to claim 1, characterized in that: The connecting portion (21) has connecting wings (23) located on both sides of the protruding portion (22) to increase the connection area between the connecting portion (21) and the isolation layer (10).

7. The closely packed vertical cavity surface emitting laser according to claim 1, characterized in that: The dielectric through hole (30) corresponds to the protruding portion (22) so that the protruding portion (22) is exposed.

8. The compact vertical cavity surface emitting laser according to any one of claims 1 to 7, characterized in that: The main body parts (11) are multiple and spaced apart, and the three additional parts (12) close to each other on three adjacent main body parts (11) are integrally formed.

9. The compact vertical cavity surface emitting laser according to claim 1, characterized in that: The main body parts (11) are multiple and arranged at intervals, and three adjacent main body parts (11) share one P-type contact electrode (20), and two adjacent main body parts (11) share one oxidation trench (40).

10. The compact vertical cavity surface emitting laser according to any one of claims 1 to 7, characterized in that: The oxidation groove (40) is a polygonal structure, and at least one side of the polygonal structure is parallel to a side of the main body (11).

11. The compact vertical cavity surface emitting laser according to any one of claims 1 to 7, characterized in that: The sides of the polygonal main body (11) include straight sides and / or arc sides.

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