Vertical cavity surface emitting laser, preparation method and laser light-emitting module

Abstract

The invention discloses a vertical cavity surface emitting laser, a preparation method and a laser light emitting module, the laser comprises a laser body, the surface of the laser body is provided with an annular insulation structure, and one side of the laser body forms a circular truncated cone structure; the laser body comprises a limiting layer which is located in the circular truncated cone structure. The limiting layer comprises limiting through holes, and the diameter range of the limiting through holes is 0.5-6 microns; the ohmic contact ring is arranged on the surface of the circular truncated cone structure; the first electrode layer is arranged on the side, away from the laser body, of the ohmic contact ring, the first electrode layer is connected with the ohmic contact ring through the first opening, the number difference between carriers distributed in the center of the light-emitting hole and carriers at the edge of the light-emitting hole is reduced, and therefore the carriers in the light-emitting hole are distributed more evenly; according to the array chip, black holes are prevented from being formed in the center of emergent light spots, Gaussian light spots can be formed easily, and meanwhile the heat resistance, direct current injection resistance and large current injection resistance of the array chip can be improved.

Description

[0001] This patent application claims priority to the Chinese application "A vertical cavity surface emitting laser, preparation method and laser light-emitting module" with patent application number 2025100035422 filed on January 2, 2025. The entire contents of the above Chinese application are incorporated herein by reference. Technical Field

[0002] The embodiments of the present invention relate to the field of laser technology, and in particular to a vertical cavity surface emitting laser, a preparation method and a laser light emitting module. Background Art

[0003] Vertical Cavity Surface Emitting Laser (VCSEL) has the advantages of small size, circular output spot, single longitudinal mode output, low threshold current and easy integration of large area arrays. It is widely used in optical communication, optical interconnection and optical storage. However, there is a black core area with weak luminous energy in the center of the VCSEL emission spot, which affects the use effect. The lifespan, thermal saturation characteristics, heat resistance, high current resistance and DC resistance of VCSEL also need to be improved. Summary of the invention

[0004] The present invention provides a vertical cavity surface emitting laser, a preparation method and a laser light-emitting module, which can reduce the difference in the number of carriers distributed in the center of the light-emitting hole and the carriers at the edge of the light-emitting hole, so that the carrier distribution in the light-emitting hole is more uniform, and the formation of a black hole in the center of the light-emitting spot is avoided, which is conducive to the formation of a Gaussian spot. At the same time, a VCSEL array chip with long life, better thermal saturation characteristics, heat resistance, high current resistance and DC resistance is provided.

[0005] In a first aspect, an embodiment of the present invention provides a vertical cavity surface emitting laser, comprising:

[0006] A laser body; a ring-shaped insulating structure is arranged on the surface of the laser body, the ring-shaped insulating structure extends from the surface of the laser body into the laser body, and one side of the laser body forms a truncated cone structure; the laser body comprises a restriction layer, the restriction layer is located in the truncated cone structure; the restriction layer comprises a restriction through hole, and the diameter of the restriction through hole ranges from 0.5 to 6 um;

[0007] An ohmic contact ring, arranged on one side of the truncated cone structure;

[0008] An insulating layer is arranged on a side of the ohmic contact ring away from the laser body; the insulating layer has a first opening, and the first opening at least exposes a portion of the surface of the ohmic contact ring;

[0009] A first electrode layer is arranged on a side of the insulating layer away from the laser body; the first electrode layer is connected to the ohmic contact ring through the first opening; or the ohmic contact ring is arranged on a side of the insulating layer away from the laser body, the first opening exposes a portion of the surface of the truncated cone structure, the first electrode layer is directly connected to the ohmic contact ring, and the ohmic contact ring is connected to the laser body through the first opening;

[0010] The second electrode layer is arranged on a side of the laser body away from the first electrode layer.

[0011] Optionally, the diameter of the truncated cone structure ranges from 7 to 39 um.

[0012] Optionally, a distance between a side wall of the limiting through hole and a side wall of the truncated cone structure in a first direction ranges from 3 to 15 um; and the first direction is parallel to the ohmic contact ring.

[0013] Optionally, the orthographic projection of the inner diameter through hole of the ohmic contact ring on the truncated cone structure covers the orthographic projection of the limiting through hole on the truncated cone structure; wherein the spacing between the inner diameter edge of the ohmic contact ring and the side wall of the limiting through hole in the first direction ranges from 1 to 7 um.

[0014] Optionally, in the first direction, a distance between an inner diameter edge of the ohmic contact ring and a side wall of the first opening is greater than a distance between an outer diameter edge of the ohmic contact ring and a side wall of the first opening.

[0015] Optionally, the distance between the inner diameter edge of the ohmic contact ring and the side wall of the first opening is in the range of 0.5 to 8 um;

[0016] The distance between the outer diameter edge of the ohmic contact ring and the side wall of the first opening is in the range of 0.2 to 3 um.

[0017] Optionally, the laser body comprises a substrate, a first reflective layer, an active layer, a limiting layer and a second reflective layer stacked in sequence; wherein the active layer, the limiting layer and the second reflective layer are located in the truncated cone structure; or, part of the first reflective layer, the active layer, the limiting layer and the second reflective layer are located in the truncated cone structure;

[0018] The distance between the outer diameter edge of the ohmic contact ring and the edge of the truncated cone structure is in the range of 0.2 to 3 um.

[0019] Optionally, the first electrode layer includes a first light through hole, and the orthographic projection of the first light through hole on the substrate at least partially covers the orthographic projection of the inner diameter through hole of the ohmic contact ring on the substrate.

[0020] In a second aspect, an embodiment of the present invention provides a method for preparing a vertical cavity surface emitting laser, comprising:

[0021] Provide a laser body;

[0022] An ohmic contact ring is formed on the surface of the laser body; wherein the surface of the laser body is provided with an annular insulating structure, the annular insulating structure extends from the surface of the laser body into the laser body, and forms a truncated cone structure on one side of the laser body; the laser body includes a restriction layer, the restriction layer is located in the truncated cone structure; the restriction layer includes a restriction through hole, the diameter of the restriction through hole ranges from 0.5 to 6 um; the ohmic contact ring is located on the surface of the truncated cone structure;

[0023] An insulating layer is formed on a side of the ohmic contact ring away from the laser body; the insulating layer has a first opening, and the first opening at least exposes a portion of the surface of the ohmic contact ring;

[0024] A first electrode layer is formed on a side of the insulating layer away from the laser body; the first electrode layer is connected to the ohmic contact ring through the first opening;

[0025] or,

[0026] An insulating layer is formed on one side of the truncated cone structure; the insulating layer has a first opening, and the first opening at least partially exposes a surface of the truncated cone structure;

[0027] Forming the ohmic contact ring on a side of the insulating layer away from the laser body;

[0028] A first electrode layer is formed on a side of the ohmic contact ring away from the laser body; the first electrode layer is directly connected to the ohmic contact ring, and the ohmic contact ring is connected to the laser body through the first opening;

[0029] A second electrode layer is formed on a side of the laser body away from the first electrode layer.

[0030] In a third aspect, an embodiment of the present invention provides a laser light-emitting module, comprising the vertical cavity surface emitting laser provided by any embodiment of the present invention.

[0031] The vertical cavity surface emitting laser provided by the embodiment of the present invention sets the limiting layer in the truncated cone structure. By limiting the diameter range of the through hole to 0.5 to 6 um, the limiting through hole can have a smaller diameter, and more carriers can pass through the central part of the light-emitting hole, thereby improving the carrier distribution in the central part of the light-emitting hole, reducing the difference in the number of carriers distributed in the central part of the light-emitting hole and the carriers at the edge of the light-emitting hole, so that the carrier distribution in the light-emitting hole is more uniform, avoiding the formation of a black hole in the central part of the light-emitting spot, and facilitating the formation of a Gaussian spot. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic structural diagram of a vertical cavity surface emitting laser is provided for an embodiment of the present invention;

[0033] Figure 2 A structural schematic diagram of another vertical cavity surface emitting laser is provided for an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of the arrangement structure of a VCSEL array is provided for an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of the arrangement structure of a VCSEL array is provided for an embodiment of the present invention;

[0036] Figure 5 A method for preparing a vertical cavity surface emitting laser is provided for an embodiment of the present invention;

[0037] Figure 6 A method for preparing a vertical cavity surface emitting laser is provided for an embodiment of the present invention;

[0038] Figures 7 to 19 A schematic diagram of the intermediate structure of a VCSEL provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0040] Currently, the diameter of the light-emitting hole of power-type VCSEL is generally large, usually 6 to 50um, which makes it easy for a black hole to exist in the center of the light spot. For light-emitting chips that integrate multiple VCSEL light-emitting holes, the overall heat resistance, high current resistance and DC resistance of the chip will be poor, and the photoelectric conversion efficiency will be low.

[0041] In view of this, Figure 1 A schematic diagram of a vertical cavity surface emitting laser is provided for the embodiment of the present invention. Figure 1 ,include:

[0042] A laser body 110; an annular insulating structure 120 is provided on the surface of the laser body 110, the annular insulating structure 120 extends from the surface of the laser body 110 into the laser body 110, and a truncated cone structure 130 is formed on one side of the laser body 110; the laser body 110 includes a restriction layer 111, and the restriction layer 111 is located in the truncated cone structure 130; the restriction layer 111 includes a restriction through hole 7, and the diameter of the restriction through hole 7 ranges from 0.5 to 6 um;

[0043] The ohmic contact ring 140 is disposed on one side of the truncated cone structure 130;

[0044] The insulating layer 150 is disposed on a side of the ohmic contact ring 140 away from the laser body 110 ; the insulating layer 150 has a first opening 1 , and the first opening 1 at least exposes a portion of the surface of the ohmic contact ring 140 ;

[0045] The first electrode layer 160 is disposed on the side of the insulating layer 150 away from the laser body 110; the first electrode layer 160 is connected to the ohmic contact ring 140 through the first opening 1;

[0046] The second electrode layer 170 is disposed on a side of the laser body 110 away from the first electrode layer 160 .

[0047] Specifically, the main structure of the laser body 110 includes a substrate 112, a first reflection layer 113, an active layer 114, a confinement layer 111, and a second reflection layer 115 stacked from bottom to top. The first reflection layer 113 and the second reflection layer 115 can be Bragg reflectors. For example, the first reflection layer 113 can be N-type doped, and the second reflection layer 115 can be P-type doped. The first reflection layer 113 and the second reflection layer 115 are formed by alternating growth of two materials with different refractive indices and thicknesses of a preset light wavelength, for example, by alternating formation of gallium arsenide material layers and gallium aluminum arsenide material layers. The reflectivity of the first reflection layer 113 is close to 100%, and it can be used as a total reflection mirror of the resonant cavity; the reflectivity of the second reflection layer 115 is relatively low, and it can be used as an exit mirror of the resonant cavity. The active layer 114 between the first reflection layer 113 and the second reflection layer 115 is usually composed of a quantum well, which is used to generate photons, and the photons are reflected back and forth in the resonant cavity through the first reflection layer 113 and the second reflection layer 115 to enhance the laser effect.

[0048] An annular insulating structure 120 is disposed on the surface of the laser body 110 away from the first reflective layer 113. For example, the annular insulating structure 120 may be an annular groove 121 or an annular ion implantation structure 122. For oxidation-type VCSEL, see Figure 1 , the laser body 110 is formed with an annular groove 121 through an etching process, and the annular groove 121 can play an isolation role, thereby avoiding the influence of peripheral parasitic capacitance on the overall device, and the annular groove 121 is used to form a truncated cone structure 130 on one side of the laser body 110. Exemplarily, the width of the annular groove 121 in the first direction X is generally between 0.5 and 5 um, preferably 1 to 3 um, and the first direction is parallel to the ohmic contact ring 140. In an embodiment of the present invention, the stacked active layer 114, the limiting layer 111 and the second reflecting layer 115 are located in the truncated cone structure 130. As an optional embodiment, part of the first reflecting layer 113, the active layer 114, the limiting layer 111 and the second reflecting layer 115 are located in the truncated cone structure 130. For ion implantation VCSEL, Figure 2 A schematic diagram of a vertical cavity surface emitting laser is provided for an embodiment of the present invention. Figure 2 , an ion implantation structure 122 can be formed in the laser body 110 by ion implantation. The ion implantation structure 122 is equivalent to the annular groove 121 and can also play an isolation role. The unimplanted area constitutes a truncated cone structure 130. In the first direction X, the depth of the ion implantation can refer to the width of the annular groove 121 in the first direction X. It should be noted that the ion implantation process uses high-energy ion implantation equipment to dope charged particles with a certain energy into semiconductor materials, thereby changing the electrical and optical properties of the semiconductor materials. The energy of the ion implantation can be determined according to the mass of the ions and the implantation depth.

[0049] The limiting layer 111 is used to limit the path of light and electricity. For an oxidized VCSEL, the limiting through hole 7 can be formed in the unoxidized area by wet oxidation of both ends of the limiting layer 111. For an ion implanted VCSEL, ions can be implanted at both ends of the limiting layer 111 to form a limiting through hole 7 in the unimplanted area. The ion implantation depth of the ion implantation structure 122 needs to be less than or equal to the ion implantation depth of the limiting through hole 7 to prevent the ion implantation structure 122 from affecting the path of electrons and photons.

[0050] The limiting through hole 7 serves as a channel for current and photons, and the limiting through hole 7 can effectively reduce the threshold current of the VCSEL laser. Among them, the limiting layer 111 is located in the truncated cone structure 130, and the diameter range of the limiting through hole 7 is 0.5 to 6um. By limiting the diameter of the limiting through hole 7, in the case of a smaller diameter, the carrier distribution in the central part of the light-emitting hole can be improved, and the carriers in the light-emitting hole can be made more uniform, thereby avoiding the formation of a black hole in the central part of the light-emitting spot. Exemplarily, the diameter of the limiting through hole 7 can be 0.5um, 1.5um, 2.5um, 3.5um, 4.5um, 5.5um or 6um. When the diameter of the limiting through hole 7 is reduced to below 5.4um, the difference in the number of carriers distributed in the central part of the light-emitting hole and the edge of the light-emitting hole will be greatly reduced. With the help of the mode competition mechanism, a Gaussian spot without a black center will be formed. Therefore, preferably, the diameter range of the limiting through hole 7 is 3.5-4.7 um, for example, 3.5 um, 3.7 um, 3.9 um, 4.1 um, 4.3 um, 4.5 um or 4.7 um.

[0051] The ohmic contact ring 140 is disposed on one side of the truncated cone structure 130, and the ohmic contact ring 140 forms an ohmic contact with the second reflective layer 115. In some embodiments, in order to improve the performance of the ohmic contact, an ohmic contact connection layer may be disposed between the second reflective layer 115 and the ohmic contact ring 140. The first electrode layer 160 injects current through the ohmic contact ring 140, and the current is injected into the active layer 114 through the limiting through hole 7. After satisfying the conditions of stimulated radiation, optical gain is generated, and the generated photons are reflected back and forth between the first reflective layer 113 and the second reflective layer 115, forming a resonance of light. As the number of photons increases, the stimulated radiation effect is enhanced, and a stable laser output is finally formed.

[0052] The vertical cavity surface emitting laser provided in the embodiment of the present invention sets the limiting layer 111 in the truncated cone structure 130. By limiting the diameter range of the through hole 7 to 0.5 to 6 um, the limiting through hole 7 can have a smaller diameter, and more carriers can pass through the central part of the light-emitting hole, thereby improving the carrier distribution in the central part of the light-emitting hole, reducing the difference in the number of carriers distributed in the central part of the light-emitting hole and the carriers at the edge of the light-emitting hole, so that the carrier distribution in the light-emitting hole is more uniform, avoiding the formation of a black hole in the central part of the light-emitting spot, and facilitating the formation of a Gaussian spot.

[0053] In other embodiments, in the structure of the vertical cavity surface emitting laser, an insulating layer 150 can be directly set on one side of the truncated cone structure 130, and a first opening 1 on the insulating layer 150 exposes a portion of the truncated cone structure 130. An ohmic contact ring 140 is set on the side of the insulating layer 150 away from the truncated cone structure 130. The ohmic contact ring 140 is connected to the truncated cone structure 130 through the first opening 1, and the first electrode layer 170 is directly connected to the ohmic contact ring 140, which has the same beneficial effects as the above-mentioned embodiments and will not be repeated here.

[0054] Optionally, the diameter of the truncated cone structure 130 ranges from 7 to 39 um. By limiting the diameter of the truncated cone structure 130 to 10, the area of ​​the VCSEL light-emitting hole can be better controlled. When making a large, dense VCSEL array on a single chip, when the area of ​​the available light-emitting area of ​​the chip itself is certain, by limiting the diameter of the truncated cone structure 130 to 10, more VCSEL light-emitting holes can be set. For VCSEL chips per unit area and unit power, the number of VCSEL light-emitting heads increases, the optical power output that each VCSEL light-emitting head needs to bear will become lower, and the heat power consumption and waste heat borne will also be lower. Considering each VCSEL light-emitting head as a heat source, the distribution of the heat source on the chip will be more uniform, which is beneficial to the overall heat dissipation of the chip, thereby improving the heat resistance, high current resistance and DC resistance of the VCSEL array chip, and extending the service life. Preferably, the diameter of the truncated cone structure 130 ranges from 17 to 29 um, for example, the diameter 10 of the truncated cone structure 130 is 17 um, 19 um, 21 um, 23 um, 25 um, 27 um or 29 um. Furthermore, by limiting the diameter 10 of the truncated cone structure 130, it is also possible to better control the diameter of the limiting through hole 7. For example, for an oxidized VCSEL, after obtaining a truncated cone structure 130 with a smaller diameter through an etching process, the original oxidation process of the limiting layer 111 is not changed, that is, the oxidation depth remains unchanged, and a smaller limiting through hole 7 diameter relative to the original design can be obtained, thereby reducing the difficulty of process preparation. And when the diameter of the truncated cone structure 130 ranges from 7 to 39 um, the path of the heat at the center of the truncated cone structure 130 to the surrounding area becomes shorter, which is conducive to the discharge of central heat, and the central hole burning effect is weak, which is further conducive to the formation of a Gaussian light spot without a black hole.

[0055] Optionally, the distance between the sidewall of the limiting through hole 7 and the sidewall of the truncated cone structure 130 in the first direction X is in the range of 3 to 15 um; the first direction is parallel to the ohmic contact ring 140. That is to say, for an oxidized VCSEL, the length range of the oxidation depth 9 of the limiting layer 111 can be controlled in the range of 3 to 15 um; preferably, the length range of the oxidation depth 9 is 7 to 12 um, for example, the oxidation depth 9 is 7 um, 9 um, 11 um or 12 um. For an ion implanted VCSEL, the depth range of the ion implantation of the limiting layer 111 can be controlled in the range of 1 to 15 um.

[0056] Continue to see Figure 1 Optionally, the orthographic projection of the inner diameter through hole of the ohmic contact ring 140 on the truncated cone structure 130 covers the orthographic projection of the limiting through hole 7 on the truncated cone structure 130; that is, in the stacking direction, the limiting through hole 7 is located below the ohmic contact ring 140, and the photons emitted by the limiting through hole 7 can be emitted through the inner diameter through hole of the ohmic contact ring 140. The diameter of the inner diameter through hole of the ohmic contact ring 140 is larger than the diameter of the limiting through hole 7, thereby avoiding the influence of the boundary of the ohmic contact ring 140 on the emitted light. Among them, the length range of the spacing 3 between the inner diameter edge of the ohmic contact ring 140 and the side wall of the limiting through hole 7 in the first direction X is 1 to 7um. Exemplarily, the spacing can be 1um, 2um, 4um, 6um or 7um, and preferably, the spacing is 2 to 4um. By limiting the length range of the interval 3 between the inner diameter edge of the ohmic contact ring 140 and the side wall of the limiting through hole 7 in the first direction X, the inner diameter edge of the limiting ohmic contact ring 140 can be made closer to the limiting through hole 7, thereby reducing the path of the current injected by the ohmic contact ring 140 through the limiting through hole 7, which helps to reduce the energy loss in the current transmission process, reduce the resistance and voltage of the VCSEL, and improve the electro-optical conversion efficiency and performance of the VCSEL.

[0057] Optionally, in the first direction X, a distance 2 between an inner diameter edge of the ohmic contact ring 140 and a side wall of the first opening 1 is greater than or equal to a distance 4 between an outer diameter edge of the ohmic contact ring 140 and a side wall of the first opening 1 .

[0058] Specifically, the first opening 1 is a channel for the first electrode layer 160 to connect to the ohmic contact ring 140, and is also the narrowest channel for current injection. Exemplarily, the diameter range of the first opening 1 is usually between 0.4 and 5.5 um, and preferably, the diameter range of the first opening 1 is 1.6 to 2.4 um. The spacing 2 between the inner diameter edge of the ohmic contact ring 140 and the side wall of the first opening 1 is greater than or equal to the spacing 4 between the outer diameter edge of the ohmic contact ring 140 and the side wall of the first opening 1, which means that the first opening 1 is closer to the outer diameter edge of the ohmic contact ring 140 in position. Optionally, the spacing range between the inner diameter edge of the ohmic contact ring 140 and the side wall of the first opening 1 is 0.5 to 8 um, and preferably, the spacing range between the inner diameter edge of the ohmic contact ring 140 and the side wall of the first opening 1 is 4 to 6 um. The spacing range between the outer diameter edge of the ohmic contact ring 140 and the side wall of the first opening 1 is 0.2 to 3 um. Preferably, the distance between the outer diameter edge of the ohmic contact ring 140 and the side wall of the first opening 1 is in the range of 0.5 to 2 um.

[0059] When the first opening 1 is closer to the outer diameter edge of the ohmic contact ring 140, in the VCSEL design process, the contact area between the ohmic contact ring 140 and the semiconductor can be increased by increasing the distance between the inner diameter edge of the ohmic contact ring 140 and the side wall of the first opening 1, so as to reduce the working voltage of the VCSEL. The path of the current injected by the ohmic contact ring 140 through the limiting through hole 7 can also be further reduced by increasing the distance between the inner diameter edge of the ohmic contact ring 140 and the side wall of the first opening 1. Further, when the first opening 1 is closer to the outer diameter edge of the ohmic contact ring 140, the edge of the first electrode layer 160 close to the light-emitting hole can be offset away from the center of the light-emitting hole, thereby avoiding the obstruction of the light-emitting hole by the thicker first electrode layer 160 and improving the light output rate of the light-emitting hole. Because the first electrode layer is thick gold, the thickness of the gold is 0.5 to 8 um, usually 2 to 6.5 um, and there is a risk of blocking light.

[0060] Furthermore, the spacing 5 between the outer diameter edge of the ohmic contact ring 140 and the edge of the truncated cone structure 130 will also affect the performance of the VCSEL. For example, if the spacing between the outer diameter edge of the ohmic contact ring 140 and the edge of the truncated cone structure 130 is too large, it will lead to a waste of chip area, and may also cause uneven current injection between the ohmic contact ring 140 and the truncated cone structure 130, thereby increasing the threshold current. If the spacing is too small, the current density at the edge of the truncated cone structure 130 will increase, resulting in an increase in thermal effect, which will also affect the threshold current of the VCSEL. In the embodiment of the present invention, the length range of the spacing 5 between the outer diameter edge of the ohmic contact ring 140 and the edge of the truncated cone structure 130 is 0.2 to 3um. Preferably, the length range of the spacing 5 between the outer diameter edge of the ohmic contact ring 140 and the edge of the truncated cone structure 130 is 0.5 to 2um.

[0061] Optionally, the first electrode layer 160 includes a first light hole, and the orthographic projection of the first light hole on the substrate 112 at least partially covers the orthographic projection of the inner diameter hole of the ohmic contact ring 140 on the substrate 112. Specifically, the first light hole is used for laser output, and in the stacking direction, the inner diameter hole of the ohmic contact ring 140 is located below the first light hole, and the emitted light can be emitted outward through the first light hole, and the diameter of the first light hole can be greater than or equal to the diameter of the inner diameter hole of the ohmic contact ring 140, so as to avoid the boundary of the first light hole blocking the emitted light.

[0062] Optionally, the length range of the spacing 6 between the side wall of the first light hole and the side wall of the first opening 1 is 0-3um. When the spacing 6 between the side wall of the first light hole and the side wall of the first opening 1 is too large, the side wall of the first light hole is easy to block the outgoing light and affect the light extraction efficiency. Preferably, the spacing between the side wall of the first light hole and the side wall of the first opening 1 is in the range of 0.5-2um, which can ensure that the first electrode layer 160 can be connected to the ohmic contact ring 140 through the first opening 1, and at the same time avoid the spacing 6 between the side wall of the first light hole and the side wall of the first opening 1 is too small, so that the first electrode layer 160 is insufficiently filled in the first opening 1 during the preparation process, forming a structural defect of a gap, and affecting the current injection of the first electrode layer 160.

[0063] The embodiment of the present invention also provides a laser light-emitting module, which includes a plurality of vertical cavity surface emitting lasers. Exemplarily, the laser light-emitting module can be a VCSEL chip. When a large, dense VCSEL array is made on the VCSEL chip, the limiting layer 111 of each VCSEL is set in the truncated cone structure 130. By limiting the diameter range of the through hole 7 to 0.5 to 6 um, the limiting through hole 7 can have a smaller diameter, and more carriers can pass through the central part of the light-emitting hole, thereby improving the carrier distribution in the central part of the light-emitting hole, and reducing the difference in the number of carriers distributed in the central part of the light-emitting hole and the carriers at the edge of the light-emitting hole, so that the carrier distribution in the light-emitting hole is more uniform, avoiding the formation of a black hole in the central part of the light-emitting spot, and facilitating the formation of a Gaussian spot. And when the area of ​​the light-emitting area available to the VCSEL chip itself is certain, by limiting the diameter 10 of the truncated cone structure 130, more VCSEL light-emitting holes can be set. Exemplarily, Figure 3 and Figure 4 A schematic diagram of the arrangement structure of a VCSEL array is provided for an embodiment of the present invention, see Figure 3 and Figure 4, based on the VCSEL of any embodiment of the present invention, when a large, dense VCSEL array is made on a VCSEL chip, the hole spacing between the light-emitting holes of the VCSEL can be set in the range of 8 to 50um. Preferably, the hole spacing can be set in the range of 18 to 35um, so as to set more VCSEL light-emitting holes. For VCSEL chips per unit area and unit power, the number of VCSELs increases, and the optical power output that each VCSEL light-emitting hole needs to bear will become lower, and the power consumption and waste heat will also become lower. Considering each VCSEL as a heat source, the distribution of the heat source on the chip will be more uniform, which is beneficial to the overall heat dissipation of the chip, thereby improving the service life and heat resistance, high current and direct current resistance of the VCSEL chip.

[0064] Figure 5 A method for preparing a vertical cavity surface emitting laser is provided for an embodiment of the present invention. Figure 5 ,include:

[0065] S110, providing a laser body 110;

[0066] S120, forming an ohmic contact ring 140 on the surface of the laser body 110; wherein, an annular insulating structure 120 is provided on the surface of the laser body 110, the annular insulating structure 120 extends from the surface of the laser body 110 to the inside of the laser body 110, and forms a truncated cone structure 130 on one side of the laser body 110; the laser body 110 includes a restriction layer 111, and the restriction layer 111 is located in the truncated cone structure 130; the restriction layer 111 includes a restriction through hole 7, and the diameter range of the restriction through hole 7 is 0.5 to 6 um; the ohmic contact ring 140 is located on the surface of the truncated cone structure 130;

[0067] Specifically, the main structure of the laser body 110 includes a substrate 112, a first reflection layer 113, an active layer 114, a confinement layer 111, and a second reflection layer 115 stacked from bottom to top. The first reflection layer 113 and the second reflection layer 115 may be Bragg reflectors, which may be formed by alternately stacking semiconductor materials with different refractive indices. Exemplarily, the first reflection layer 113 may be N-type doped, and the second reflection layer 115 may be P-type doped. The first reflection layer 113 and the second reflection layer 115 are formed by alternately growing two materials with different refractive indices and thicknesses of a preset light wavelength, for example, by alternately forming a gallium arsenide material layer and a gallium aluminum arsenide material layer. The reflectivity of the first reflection layer 113 is close to 100%, and it can be used as a total reflection mirror of the resonant cavity. The reflectivity of the second reflection layer 115 is relatively low, and it can be used as an exit mirror of the resonant cavity. The active layer 114 between the first reflective layer 113 and the second reflective layer 115 is usually composed of a quantum well for generating photons. The photons are reflected back and forth in the resonant cavity through the first reflective layer 113 and the second reflective layer 115 to enhance the laser effect.

[0068] An annular insulating structure 120 is disposed on the surface of the laser body 110 away from the first reflective layer 113. For example, the annular insulating structure 120 may be an annular groove 121 or an annular ion implantation structure. Figure 1 , the laser body 110 is formed into an annular groove 121 by an etching process, and the annular groove 121 can play an isolation role, thereby avoiding the influence of peripheral parasitic capacitance on the overall device, and the annular groove 121 is used to form a truncated cone structure 130 on one side of the laser body 110. Exemplarily, the width 8 of the annular groove 121 in the first direction X is usually between 0.5 and 5 um, preferably 1 to 3 um, and the first direction is parallel to the ohmic contact ring 140. For ion implantation VCSEL, see Figure 2 , an annular insulation can be formed in the laser body 110 by ion implantation, and the annular insulation is equivalent to the annular groove 121 and can also play an isolation role, and the unimplanted area constitutes a truncated cone structure 130. The depth of the ion implantation in the first direction X can refer to the width of the annular groove 121 in the first direction X. It should be noted that the ion implantation process uses high-energy ion implantation equipment to dope charged particles with a certain energy into semiconductor materials, thereby changing the electrical and optical properties of the semiconductor materials. The energy of the ion implantation can be determined according to the mass of the ions and the implantation depth.

[0069] The limiting layer 111 is used to limit the path of light and electricity. For an oxidized VCSEL, the limiting through hole 7 can be formed in the unoxidized area by wet oxidation of both ends of the limiting layer 111. For an ion-implanted VCSEL, ions can be implanted at both ends of the limiting layer 111 to form a limiting through hole 7 in the unimplanted area. The ion implantation depth for forming an annular insulation in the first direction needs to be less than or equal to the ion implantation depth for forming the limiting through hole 7 to avoid affecting the path of electrons and photons.

[0070] The limiting through hole 7 serves as a channel for current and photons, and the limiting through hole 7 can effectively reduce the threshold current of the VCSEL laser. Among them, the limiting layer 111 is located in the truncated cone structure 130, and the diameter range of the limiting through hole 7 is 0.5 to 6um. By limiting the diameter of the limiting through hole 7, in the case of a smaller diameter, the carrier distribution in the central part of the light-emitting hole can be improved, and the carriers in the light-emitting hole can be made more uniform, thereby avoiding the formation of a black hole in the central part of the light-emitting spot. Exemplarily, the diameter of the limiting through hole 7 can be 0.5um, 1.5um, 2.5um, 3.5um, 4.5um, 5.5um or 6um. When the diameter of the limiting through hole 7 is reduced to below 5.4um, the difference in the number of carriers distributed in the central part of the light-emitting hole and the edge of the light-emitting hole will be greatly reduced. With the help of the mode competition mechanism, a Gaussian spot without a black center will be formed. Preferably, the diameter of the limiting through hole 7 is in the range of 3.5 to 4.7 um, for example, 3.5 um, 3.7 um, 3.9 um, 4.1 um, 4.3 um, 4.5 um or 4.7 um.

[0071] An ohmic contact ring 140 is disposed on the surface of the truncated cone structure 130 to form an ohmic contact. In some embodiments, an ohmic contact connection layer may be disposed between the second reflective layer 115 and the ohmic contact ring 140 to improve the performance of the ohmic contact.

[0072] S130, forming an insulating layer 150 on a side of the ohmic contact ring 140 away from the laser body 110; the insulating layer 150 has a first opening 1, and the first opening 1 at least exposes a portion of the surface of the ohmic contact ring 140;

[0073] S140, forming a first electrode layer 160 on the side of the insulating layer 150 away from the laser body 110; the first electrode layer 160 is connected to the ohmic contact ring 140 through the first opening 1; the first electrode layer 160 injects current through the ohmic contact ring 140, and the current is injected into the active layer 114 through the limiting through hole 7, and after satisfying the conditions of stimulated radiation, optical gain is generated, and the generated photons are reflected back and forth between the first reflective layer 113 and the second reflective layer 115, forming optical resonance. As the number of photons increases, the stimulated radiation effect is enhanced, and finally a stable laser output is formed.

[0074] S150 , forming a second electrode layer 170 on a side of the laser body 110 away from the first electrode layer 160 .

[0075] Figure 6 Another method for preparing a vertical cavity surface emitting laser is provided for the embodiment of the present invention. Figure 6 ,include:

[0076] S100, providing a laser body 110; wherein a ring-shaped insulating structure 120 is provided on the surface of the laser body 110, the ring-shaped insulating structure 120 extends from the surface of the laser body 110 into the laser body 110, and forms a truncated cone structure 130 on one side of the laser body 110; the laser body 110 includes a restriction layer 111, and the restriction layer 111 is located in the truncated cone structure 130; the restriction layer 111 includes a restriction through hole 7, and the diameter of the restriction through hole 7 ranges from 0.5 to 6 um; an ohmic contact ring 140 is located on the surface of the truncated cone structure 130;

[0077] S101, forming an insulating layer 150 on the surface of the laser body 110; the insulating layer 150 has a first opening 1, and the first opening 1 at least exposes a portion of the surface of the truncated cone structure;

[0078] S102, forming an ohmic contact ring 140 on a side of the insulating layer 150 away from the laser body 110, wherein the ohmic contact ring 140 is connected to the laser body 110 through the first opening 1;

[0079] S103 , forming a first electrode layer 160 on a side of the ohmic contact ring 140 away from the laser body 110 ; the first electrode layer 160 is connected to the ohmic contact ring 140 .

[0080] S104 , forming a second electrode layer 170 on a side of the laser body 110 away from the first electrode layer 160 .

[0081] The embodiment of the present invention further provides a method for preparing an oxidized vertical cavity surface emitting laser, wherein: Figures 7 to 19 The intermediate structure diagram provided by the embodiment of the present invention is shown in FIG. Figures 7 to 19 ,include:

[0082] S210, providing a VCSEL epitaxial wafer (laser body 110). Exemplarily, the shape of the epitaxial wafer may be circular, rectangular or square, and no specific limitation is made here.

[0083] S220, preparing an ohmic contact ring 140 on the surface of the VCSEL epitaxial wafer, such as Figure 7 shown.

[0084] S230, forming an insulating layer 150 on one side of the ohmic contact ring 140 by using a vapor deposition technique. The material of the insulating layer 150 may be silicon nitride or silicon oxide, or a mixture of silicon nitride and silicon oxide. For example, the vapor deposition technique may be a plasma enhanced chemical vapor deposition technique. Figure 8 shown.

[0085] S240, using photolithography technology to expose the etching area of ​​the annular groove 121, such as Fig. 9 shown.

[0086] S250, an annular groove 121 is obtained by etching, and the annular groove 121 can play an isolation role, thereby avoiding the influence of peripheral parasitic capacitance on the overall device, and the annular groove 121 is used to form a truncated cone structure 130 on one side of the laser body 110. Fig.10 shown.

[0087] S260: The restriction layer 111 is located in the truncated cone structure 130, and a restriction through hole 7 is formed in the restriction layer 111 by a wet oxidation process. Fig.11 shown.

[0088] S270, forming an insulating layer 150 by vapor deposition technology again to protect the oxidized active layer 114. Fig.12 shown.

[0089] S280, forming a first opening 1 on the truncated cone structure 130, wherein the first opening 1 exposes a portion of the ohmic contact ring 140 to form a path for current injection. Fig.13 shown.

[0090] S290, plating seed gold 310 (seed layer) to prepare for electroplating to form the first electrode layer 160, such as Fig.14 shown.

[0091] S300, performing photolithography before electroplating to define the pattern morphology after electroplating 320, such as Fig.15 shown.

[0092] S310, electroplating is performed to obtain the first electrode layer 160, and reverse electroplating or etching of the seed gold is performed after the electroplating, so as to remove the seed gold and form a defined pattern morphology. Fig.16 shown.

[0093] S320, using atomic layer deposition technology to plate a protective layer 330 to form an isolation protection for the chip, such as Fig.17 It should be noted that this process is optional and is not a necessary process in the process of preparing VCSEL.

[0094] S330, removing part of the coating area to expose part of the first electrode layer 160 as a connection pad. Fig.18 shown.

[0095] S340, wafer backside process, forming the ohmic contact layer and the second electrode layer 170 on the backside. Fig.19 shown.

[0096] S350: Cutting the wafer to form a VCSEL chip having a single VCSEL or a VCSEL chip having a VCSEL array.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vertical cavity surface emitting laser, characterized in that: include: A laser body; a ring-shaped insulating structure is arranged on the surface of the laser body, the ring-shaped insulating structure extends from the surface of the laser body into the laser body, and one side of the laser body forms a truncated cone structure; the laser body comprises a restriction layer, the restriction layer is located in the truncated cone structure; the restriction layer comprises a restriction through hole, the diameter of the restriction through hole ranges from 0.5 to 6 um; an ohmic contact ring is arranged on one side of the truncated cone structure; An insulating layer is arranged on a side of the ohmic contact ring away from the laser body; the insulating layer has a first opening, and the first opening at least exposes a portion of the surface of the ohmic contact ring; A first electrode layer is arranged on a side of the insulating layer away from the laser body; the first electrode layer is connected to the ohmic contact ring through the first opening; or the ohmic contact ring is arranged on a side of the insulating layer away from the laser body, the first opening exposes a portion of the surface of the truncated cone structure, the first electrode layer is directly connected to the ohmic contact ring, and the ohmic contact ring is connected to the laser body through the first opening; The second electrode layer is arranged on a side of the laser body away from the first electrode layer.

2. The vertical cavity surface emitting laser according to claim 1, characterized in that: The diameter of the truncated cone structure ranges from 7 to 39 um.

3. The vertical cavity surface emitting laser according to claim 2, characterized in that: The distance between the side wall of the limiting through hole and the side wall of the truncated cone structure in the first direction is in the range of 3 to 15 um; the first direction is parallel to the ohmic contact ring.

4. The vertical cavity surface emitting laser according to claim 3, characterized in that: The orthographic projection of the inner diameter through hole of the ohmic contact ring on the truncated cone structure covers the orthographic projection of the limiting through hole on the truncated cone structure; wherein the spacing between the inner diameter edge of the ohmic contact ring and the side wall of the limiting through hole in the first direction ranges from 1 to 7 um.

5. The vertical cavity surface emitting laser according to claim 4, characterized in that: In the first direction, a distance between an inner diameter edge of the ohmic contact ring and a side wall of the first opening is greater than or equal to a distance between an outer diameter edge of the ohmic contact ring and a side wall of the first opening.

6. The vertical cavity surface emitting laser according to claim 5, characterized in that: The distance between the inner diameter edge of the ohmic contact ring and the side wall of the first opening is in the range of 0.5 to 8 um; The distance between the outer diameter edge of the ohmic contact ring and the side wall of the first opening is in the range of 0.2 to 3 um.

7. The vertical cavity surface emitting laser according to any one of claims 1 to 6, characterized in that: The laser body comprises a substrate, a first reflection layer, an active layer, a restriction layer and a second reflection layer stacked in sequence; wherein the active layer, the restriction layer and the second reflection layer are located in the truncated cone structure; or, part of the first reflection layer, the active layer, the restriction layer and the second reflection layer are located in the truncated cone structure; The distance between the outer diameter edge of the ohmic contact ring and the edge of the truncated cone structure is in the range of 0.2 to 3 um.

8. The vertical cavity surface emitting laser according to claim 7, characterized in that: The first electrode layer includes a first light through hole, and an orthographic projection of the first light through hole on the substrate at least partially covers an orthographic projection of the inner diameter through hole of the ohmic contact ring on the substrate.

9. A method for preparing a vertical cavity surface emitting laser, characterized in that: include: Provide a laser body; An ohmic contact ring is formed on the surface of the laser body; The surface of the laser body is provided with an annular insulating structure, the annular insulating structure extends from the surface of the laser body into the laser body, and forms a truncated cone structure on one side of the laser body; the laser body includes a restriction layer, the restriction layer is located in the truncated cone structure; the restriction layer includes a restriction through hole, the diameter of the restriction through hole ranges from 0.5 to 6 um; the ohmic contact ring is located on the surface of the truncated cone structure; forming an insulating layer on a side of the ohmic contact ring away from the laser body; The insulating layer has a first opening, and the first opening at least exposes a portion of the surface of the ohmic contact ring; forming a first electrode layer on a side of the insulating layer away from the laser body; The first electrode layer is connected to the ohmic contact ring through the first opening; or, forming an insulating layer on one side of the truncated cone structure; The insulating layer has a first opening, and the first opening at least exposes a portion of the surface of the truncated cone structure; Forming the ohmic contact ring on a side of the insulating layer away from the laser body; A first electrode layer is formed on a side of the ohmic contact ring away from the laser body; the first electrode layer is directly connected to the ohmic contact ring, and the ohmic contact ring is connected to the laser body through the first opening; A second electrode layer is formed on a side of the laser body away from the first electrode layer.

10. A laser light emitting module, characterized in that: A vertical cavity surface emitting laser comprising any one of claims 1-8.

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