CN110233424B - High-power vertical cavity surface emitting laser with integrated light emitting region - Google Patents
High-power vertical cavity surface emitting laser with integrated light emitting region Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/18—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
- H01S5/183—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
- H01S5/18308—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL] having a special structure for lateral current or light confinement
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/18—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
- H01S5/183—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
- H01S5/18308—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL] having a special structure for lateral current or light confinement
- H01S5/18319—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL] having a special structure for lateral current or light confinement comprising a periodical structure in lateral directions
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Abstract
The invention provides a high-power vertical cavity surface emitting laser with an integrated light emitting region, which comprises: the transmitting hole is internally provided with an isolation groove which isolates the transmitting hole part to form communicated long and narrow transmitting areas, and an insulating layer is arranged in the isolation layer; and the conductive layer is filled in the isolation groove, extends towards two sides and forms ohmic contact with the long and narrow emission region. The invention separates the emitting hole of the vertical cavity surface emitting laser with large oxidation aperture into a long and narrow emitting area, the long and narrow emitting area is contacted with the conducting layer, on one hand, the current path in the emitting hole is increased, the current density of the middle area of the vertical cavity surface emitting laser with large oxidation aperture can be effectively increased, on the other hand, the current can be transversely transmitted from the conducting layer, the uniformity of the current density distribution in the emitting hole is greatly improved, and the conversion efficiency is improved. Meanwhile, the coherence of emergent light is kept in a large range. The invention can be applied to the fields of laser radar, infrared cameras, depth recognition detectors and the like.
Description
Technical Field
The invention belongs to the field of design and manufacture of semiconductor lasers, and particularly relates to a high-power vertical cavity surface emitting laser with an integrated light emitting region.
Background
The Vertical Cavity Surface Emitting Laser (VCSEL) is developed on the basis of gallium arsenide semiconductor materials, is different from other light sources such as a Light Emitting Diode (LED) and a Laser Diode (LD), has the advantages of small volume, circular output light spots, single longitudinal mode output, small threshold current, low price, easiness in integration into a large-area array and the like, and is widely applied to the fields of optical communication, optical interconnection, optical storage and the like.
Vertical Cavity Surface Emitting Lasers (VCSELs) are a new type of laser that emits light vertically from the surface, and a different structure from conventional edge emitting lasers brings many advantages: the coupling efficiency of the optical fiber and the optical fiber is greatly improved by the small divergence angle and the circularly symmetric far-field and near-field distribution without a complicated and expensive beam shaping system, and the coupling efficiency of the optical fiber and the multimode optical fiber is proved to be more than 90 percent; the optical cavity is extremely short in length, so that the longitudinal mode spacing is enlarged, single longitudinal mode operation can be realized in a wider temperature range, and the dynamic modulation frequency is high; the on-chip test can be carried out, and the development cost is greatly reduced; the light-emitting direction is vertical to the substrate, the integration of a high-density two-dimensional area array can be easily realized, the higher power output is realized, and a plurality of lasers can be arranged in parallel in the direction vertical to the substrate, so the laser array is very suitable for being applied to the fields of parallel optical transmission, parallel optical interconnection and the like, the laser array is successfully applied to single-channel and parallel optical interconnection at unprecedented speed, and a great amount of application is obtained in broadband Ethernet and high-speed data communication network with high cost performance; most attractive is that its manufacturing process is compatible with Light Emitting Diodes (LEDs), which are inexpensive to manufacture on a large scale.
Vertical Cavity Surface Emitting Lasers (VCSELs) are widely used in the fields of optical communication, optical storage, optical interconnection, optical computing, solid-state lighting, laser printing, biosensing, and the like. In recent years, larger-scale application is in emerging markets of 3D face recognition, proximity sensors, laser radars, infrared camera shooting, depth detection and the like. In many practical applications, a Vertical Cavity Surface Emitting Laser (VCSEL) is required to be capable of achieving high energy density operation, and some lasers are required to maintain certain coherence of a laser light source. Making the light emitting apertures in an array can increase the light emitting power, but the energy density is limited by the spacing between the light emitting points, and coherence can also be eliminated (good for some applications, while for others it is desirable to preserve coherence). Increasing the oxide pore size is a simple and feasible solution to increase the energy density and maintain coherence. However, a Vertical Cavity Surface Emitting Laser (VCSEL) with a large oxide aperture has a problem that the current density distribution is not uniform, which results in a low conversion power and a poor uniformity of light intensity distribution.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, the present invention provides a high-power vcsel with a monolithic light emitting region, which is used to solve the problems of non-uniform current density distribution of the large-aperture vcsel.
To achieve the above and other related objects, the present invention provides a high power vcsel having a monolithically light emitting region, the vcsel comprising: the transmitting hole is internally provided with an isolation groove, the isolation groove isolates the transmitting hole part to form a long and narrow transmitting area, and the long and narrow transmitting areas are communicated; the insulating layer is formed at the bottom and the side wall of the isolation groove; and the conducting layer is filled in the isolation groove, extends to the long and narrow emission region towards two sides of the isolation groove and forms ohmic contact with the long and narrow emission region.
Optionally, the width of the elongated emitting region is between 5 and 50 micrometers.
Optionally, the width of the isolation groove is between 2 micrometers and 10 micrometers.
Optionally, the elongated emission regions are arranged in a fishbone shape, and include an elongated emission connection region and a plurality of elongated emission toothed regions connected to both sides of the elongated emission connection region, and the plurality of elongated emission toothed regions are spaced by the isolation groove.
Optionally, the elongated emission regions are arranged in a spiral shape, and the elongated emission regions are separated by spiral isolation grooves.
Optionally, the elongated emission region includes a first elongated emission connection region and a second elongated emission connection region that intersect perpendicularly to cut the emission hole into four quadrant regions, each of the quadrant regions further includes a plurality of elongated emission tooth regions respectively connected to the first elongated emission connection region and the second elongated emission connection region, and the elongated emission tooth regions in any two adjacent quadrant regions are connected to different elongated emission connection regions and are perpendicular to each other.
Optionally, the radial width of the emission aperture is not less than 50 microns.
Optionally, the radial width of the emission hole ranges from 100 micrometers to 1000 micrometers.
Optionally, the vcsel further includes an upper electrode structure surrounding the emission hole, and the conductive layer is connected to the upper electrode structure.
Optionally, the vertical cavity surface emitting laser is a front surface emitting structure, and the vertical cavity surface emitting laser includes: the back surface of the substrate is provided with a lower electrode structure; an N-type conductive lower mirror located over the substrate; an active layer located over the N-type conductive lower mirror; a P-type conductive upper mirror located above the active layer, the P-type conductive upper mirror having a current confinement layer therein and the emission aperture being defined by the current confinement layer; a dielectric layer located over the P-type conductive upper mirror; an isolation trench extending from the P-type conductive upper mirror into the N-type conductive lower mirror to isolate the emission hole portion to form an elongated emission region, wherein the P-type conductive upper mirror, the active layer, and the N-type conductive lower mirror of the elongated emission region are connected; the insulating layer is formed at the bottom and the side wall of the isolation groove; and the conducting layer is filled in the isolation groove, extends to the long and narrow emission region towards two sides of the isolation groove and forms ohmic contact with the P-type conductive upper reflecting mirror in the long and narrow emission region.
Optionally, the conductive layer includes a stacked structure of a Ti layer, a Pt layer, and an Au layer stacked in this order.
Optionally, the vertical cavity surface emitting laser is a back surface emitting structure, and the vertical cavity surface emitting laser includes: the back surface of the P-type conductive lower reflecting mirror is provided with a lower electrode structure; an active layer located over the P-type conductive lower mirror; an N-type conductive upper mirror located above the active layer, the N-type conductive upper mirror having a current confinement layer therein and the emission aperture being defined by the current confinement layer; a substrate located over the N-type conductive upper mirror; a dielectric layer formed on the substrate; an isolation trench extending from the substrate into the P-type conductive lower mirror to partially isolate the emission hole to form an elongated emission region, wherein the P-type conductive lower mirror, the active layer and the N-type conductive upper mirror of the elongated emission region are in communication; the insulating layer is formed at the bottom and the side wall of the isolation groove; and the conducting layer is filled in the isolation groove, extends to the long and narrow emission region towards two sides of the isolation groove and forms ohmic contact with the substrate in the long and narrow emission region.
Optionally, the conductive layer includes a stacked structure of an Au layer, a Ge layer, a Ni layer, and an Au layer stacked in this order.
Optionally, the vertical cavity surface emitting laser is a back surface emitting structure, and the vertical cavity surface emitting laser includes: the back surface of the P-type conductive lower reflecting mirror is provided with a lower electrode structure; an active layer located over the P-type conductive lower mirror; an N-type conductive upper mirror located above the active layer, the N-type conductive upper mirror having a current confinement layer therein and the emission aperture being defined by the current confinement layer; the substrate is positioned above the N-type conductive upper reflecting mirror, and the substrate positioned in the emitting hole area is removed to form an emitting cavity so as to expose the N-type conductive upper reflecting mirror; the dielectric layer is formed on the exposed N-type conductive upper reflecting mirror; the isolation groove extends from the N-type conductive upper reflecting mirror exposed out of the emission cavity into the P-type conductive lower reflecting mirror to isolate the emission hole part to form an elongated emission region, and the P-type conductive lower reflecting mirror, the active layer and the N-type conductive upper reflecting mirror of the elongated emission region are communicated; the insulating layer is formed at the bottom and the side wall of the isolation groove; and the conducting layer is filled in the isolation groove, extends to the long and narrow emission region towards two sides of the isolation groove and forms ohmic contact with the N-type conducting upper reflecting mirror in the long and narrow emission region.
Optionally, the conductive layer includes a stacked structure of an Au layer, a Ge layer, a Ni layer, and an Au layer stacked in this order.
Optionally, the current confinement layer includes one of an air pillar type current confinement structure, an ion implantation type current confinement structure, a buried heterojunction type current confinement structure, and an oxidation confinement type current confinement structure.
The invention also provides a laser radar, and the light source of the laser radar adopts the high-power vertical cavity surface emitting laser with the integrated light emitting area.
The invention also provides an infrared camera, and a light source of the infrared camera adopts the high-power vertical cavity surface emitting laser with the integrated light emitting area.
The invention also provides a 3D depth recognition detector, and a light source of the depth recognition detector adopts the high-power vertical cavity surface emitting laser with the integrated light emitting area.
As described above, the high-power vertical cavity surface emitting laser with a light emitting region of the present invention has the following advantages:
according to the invention, the emission hole of the vertical cavity surface emitting laser with the large oxidation aperture is isolated into the long and narrow emission region through the isolation groove and the conductive layer arranged in the isolation groove, and the long and narrow emission region is in contact with the conductive layer in the isolation groove, so that on one hand, a current path in the emission hole is increased, the current density of the middle region of the vertical cavity surface emitting laser with the large oxidation aperture can be effectively increased, on the other hand, the current can be transversely transmitted from the conductive layer, the uniformity of the current density distribution in the emission hole is greatly improved, and the conversion efficiency is improved, and the conversion efficiency of the vertical cavity surface emitting laser can be as high as 30-50%.
The plurality of long and narrow emission regions are positioned in the same emission hole and communicated with each other, have coherence and can be matched with a Diffraction Optical Element (DOE), so that the signal-to-noise ratio of the vertical cavity surface emitting laser can be obviously improved. Meanwhile, the coherence of emergent light is kept in a large range. The invention can be applied to the fields of laser radar, infrared cameras, depth recognition detectors and the like.
The invention can effectively improve the power density of the vertical cavity surface emitting laser, namely, the power of the laser or the laser array in unit area, can reduce the number of the required lasers under the same optical power requirement, can substantially improve the integration level of a chip, and effectively reduce the cost of the chip.
Drawings
Fig. 1 to 2 show schematic structural diagrams of a high-power vertical cavity surface emitting laser with a one-body light emitting region according to embodiment 1 of the present invention.
Fig. 3 to 4 are schematic structural diagrams of a high-power vcsel of an integrated light emitting region in embodiment 2 of the present invention.
Fig. 5 to 6 are schematic structural views of a high-power vcsel of an integrated light emitting region in embodiment 3 of the present invention.
Fig. 7 is a schematic structural diagram of a high-power vcsel in a monolithic light emitting region in embodiment 4 of the present invention.
Fig. 8 is a schematic structural diagram of a high-power vcsel in a monolithic light emitting region according to embodiment 5 of the present invention.
Fig. 9 to 10 are schematic diagrams respectively showing current injection distribution of the high-power vcsel and the conventional vcsel of the present invention.
Description of the element reference numerals
10 emission holes, 100 elongated emission regions, 101 isolation trenches, 102 insulating layers, 103 conductive layers, 104 elongated emission connection regions, 105 elongated emission tooth-shaped regions, 106 substrates, 107 lower electrode structures, 108N-type conductive lower mirrors, 109 active layers, 110 current confinement layers, 111P-type conductive upper mirrors, 112 dielectric layers, 113 upper electrode structures, 208N-type conductive upper mirrors, 211P-type conductive lower mirrors, 200 elongated emission regions, 201 isolation trenches, 320 first elongated emission connection regions, 321 second elongated emission connection regions, 322 elongated emission tooth-shaped regions.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
Please refer to fig. 1 to 10. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.
Example 1
The embodiment provides a high-power vertical cavity surface emitting laser with an integrated light emitting region, and through research and analysis, in the conventional vertical cavity surface emitting laser with an annular upper electrode structure 113, when current is injected, the current can be mainly concentrated in the edge region of an emitting hole 10, the current in the middle region of the emitting hole 10 is small or even no current, the current distribution in the edge region of the emitting hole 10 is crowded, the current distribution in the middle region is almost zero, the overall conversion efficiency of the vertical cavity surface emitting laser is low, and the light intensity distribution in the emitting hole 10 is uneven. The principle of the design of the invention is as follows: the elongated emissive regions 100 in the emissive aperture 10 are connected together, and any distance (e.g. lateral distance) from any one of the elongated emissive regions 100 to the nearest conductive layer 103 is limited to a small distance, for example, 10 microns, while the distance (e.g. longitudinal distance) in another dimension is large, for example, more than 30 microns. The shape may also be irregular, such as a tree, and the width of the elongated emissive region 100 may or may not be uniform throughout.
As shown in fig. 1-2, fig. 2 is a schematic cross-sectional view of a-a' in fig. 1. The present embodiment provides a vertical cavity surface emitting laser including an emission hole 10, an isolation trench 101, an insulating layer 102, and a conductive layer 103.
As shown in fig. 1 and 2, an isolation trench 101 is formed in the emitter hole 10, the isolation trench 101 partially isolates the emitter hole 10 to form an elongated emitter region 100, and the elongated emitter regions 100 are connected with each other.
The width of the isolation groove 101 may be between 2 micrometers to 10 micrometers, for example, the width of the isolation groove 101 may be 2 micrometers, 3 micrometers, 5 micrometers, and the like, and the width of the isolation groove 101 selected in this embodiment is small so as to reduce the area of the emission hole 10 occupied by the isolation groove and reduce the loss of the emitted light.
The width of the long and narrow emission region 100 can be between 5 micrometers and 50 micrometers, and the width of the long and narrow emission region 100 in the range can ensure that the current can be expanded to the long and narrow emission region 100, and meanwhile, the effective light emitting width of the long and narrow emission region is ensured, and the conversion rate is improved.
The insulating layer 102 is formed on the bottom and the sidewall of the isolation trench 101, and is used to insulate the subsequent conductive layer 103 from the active region and the emitter in the trench, thereby avoiding short circuit. The insulating layer 102 may be a dielectric material such as silicon dioxide, silicon oxynitride, silicon nitride, etc. formed by a chemical vapor deposition process.
The conductive layer 103 is filled in the isolation trench 101, and the conductive layer 103 extends to the elongated emission region 100 towards two sides of the isolation trench 101 and forms an ohmic contact with the elongated emission region 100.
The radial width of the emission hole 10 is not less than 50 microns, preferably, the radial width of the emission hole 10 ranges from 100 microns to 1000 microns, for example, the aperture of the emission hole 10 may be 200 microns, 300 microns, 400 microns, etc., the emission hole 10 with a larger radial width may cause a lower current distribution uniformity of the vcsel, thereby causing a lower overall conversion efficiency of the vcsel and a non-uniform light intensity distribution in the emission hole 10, the invention separates the emission hole 10 of the vcsel with a large oxide aperture into a narrow emission region 100 by disposing an isolation trench 101 and a conductive layer 103 in the emission hole 10, the narrow emission region 100 is in contact with the conductive layer 103 in the isolation trench 101, on one hand, the current path in the emission hole 10 is increased, and the current density of the middle region of the vcsel with a large oxide aperture can be effectively increased, on the other hand, the current can be transversely transmitted from the conductive layer 103, so that the uniformity of current density distribution in the light emitting holes is greatly improved, and the conversion efficiency is improved.
As shown in fig. 1, in the present embodiment, the plurality of elongated emission regions 100 are arranged in a fishbone shape, and include an elongated emission connection region 104 and a plurality of elongated emission toothed regions 105 connected to two sides of the elongated emission connection region, and the plurality of elongated emission toothed regions 105 are separated by the isolation groove 101. The number of the elongated transmitting tooth-shaped regions 105 can be set according to the radial width of the transmitting hole 10, for example, the number of the elongated transmitting tooth-shaped regions 105 can be 6-12. The plurality of elongated emitting regions 100 are located in the same emitting hole 10 and are communicated with each other, have coherence, and can be matched with a Diffractive Optical Element (DOE), so that the signal-to-noise ratio of the vertical cavity surface emitting laser can be remarkably improved. Specifically, in the case of a conventional vertical cavity surface emitting laser array (VCSEL array), the emitted light is incoherent, and the light emitting area as a whole is large and the gap between the light emitting points is also large. The vertical cavity surface emitting laser adopts a mode of single large aperture, the light emitting point (the long and narrow emitting area 100) of the vertical cavity surface emitting laser is luminous integrally, light spots can be effectively reduced, the signal to noise ratio is improved, and meanwhile, the coherence of laser is kept, so that the vertical cavity surface emitting laser has certain advantages for optical components such as DOE. In addition, the traditional edge-emitting laser has the advantages that the fast axis and the slow axis are distinguished, the light spot is elliptical, and the divergence angles of the fast axis and the slow axis are different.
As shown in fig. 1, the vcsel further includes an upper electrode structure 113, the upper electrode structure 113 surrounds the emission hole 10, and the conductive layer 103 is connected to the upper electrode structure 113.
As shown in fig. 1 and fig. 2, the vcsel has a front emission structure, and the vcsel includes a substrate 106, an N-type conductive lower mirror 108, an active layer 109, a P-type conductive upper mirror 111, a dielectric layer 112, an isolation trench 101, an insulating layer 102, a conductive layer 103, and an upper electrode structure 113.
The substrate 106 may be a gallium arsenide substrate 106, and the back side of the substrate 106 has a lower electrode structure 107.
The N-type conductive lower mirror 108 is located on the substrate 106, and the N-type conductive lower mirror 108 may be an N-type conductive bragg reflector DBR, and the main material thereof may be gallium arsenide or the like.
The active layer 109 is located on the N-type conductive lower mirror 108, and the active layer 109 is used to convert electrical energy into optical energy and may be made of gallium arsenide or the like.
The P-type conductive upper mirror 111 is located on the active layer 109, the P-type conductive upper mirror 111 has a current confinement layer 110 surrounding the emission hole 10, the current confinement layer 110 defines the emission hole 10, and the P-type conductive upper mirror 111 may be a P-type conductive bragg mirror DBR, and a main material thereof may be gallium arsenide or the like. The N-type conductive lower mirror 108 and the P-type conductive upper mirror 111 are used for enhancing the reflection of the light generated by the active layer 109, and finally, laser is formed and emitted from the surface of the P-type conductive upper mirror 111. The current confinement layer 110 includes one of an air pillar type current confinement structure, an ion implantation type current confinement structure, a buried heterojunction type current confinement structure, and an oxidation confinement type current confinement structure, and in this embodiment, the current confinement layer 110 is an oxidation confinement type current confinement structure.
The dielectric layer 112 is located above the P-type conductive upper mirror 111, and is used for protecting the P-type conductive upper mirror 111.
The upper electrode structure 113 is located on the dielectric layer 112, and the peripheral electrode penetrates through the dielectric layer 112 and forms ohmic contact with the P-type conductive upper mirror 111.
The isolation trench 101 extends from the P-type conductive upper mirror 111 to the N-type conductive lower mirror 108 to partially isolate the emission hole 10 to form an elongated emission region 100, and the P-type conductive upper mirror 111, the active layer 109 and the N-type conductive lower mirror 108 of the elongated emission region 100 are communicated.
The insulating layer 102 is formed on the bottom and sidewalls of the isolation trench 101.
The conductive layer 103 is filled in the isolation trench 101, and the conductive layer 103 extends to the elongated emission region 100 towards two sides of the isolation trench 101 and forms an ohmic contact with the P-type conductive upper mirror 111 in the elongated emission region 100. For example, the conductive layer 103 has a stacked-layer structure including a Ti layer, a Pt layer, and an Au layer stacked in this order. Of course, the conductive layer 103 may be formed of other metal stacked layers, and is not limited to the examples listed herein.
In addition, the sidewall of the isolation trench 101 may also be oxidized by the isolation trench 101 to form a limiting oxide layer diffracting from the sidewall of the isolation trench 101 toward the elongated emitter region 100, and the extending length of the limiting oxide layer may be equal to or greater than the width of the conductive layer 103 extending to the elongated emitter tooth region 105, so as to further improve the current utilization rate.
Fig. 9 shows an injection schematic curve of current of the vcsel of this embodiment, and fig. 10 shows an injection schematic curve of current of the conventional vcsel, as can be seen from fig. 9 and fig. 10, the current distribution of the edge region of the emission hole 10 of the conventional vcsel is crowded, and the current distribution of the middle region is almost absent, which results in a low overall conversion efficiency of the vcsel.
The embodiment further provides a laser radar, wherein a light source of the laser radar adopts the high-power vertical cavity surface emitting laser in the integral light emitting area. Compared with the prior edge-emitting laser used for the laser radar, the edge-emitting laser has the advantages that the light spots are circular, and the divergence angles are rotationally symmetrical.
The embodiment further provides an infrared camera, and a light source of the infrared camera adopts the high-power vertical cavity surface emitting laser with the integrated light emitting area.
The embodiment also provides a 3D depth recognition detector, and a light source of the depth recognition detector adopts the high-power vertical cavity surface emitting laser with the integrated light emitting area.
Example 2
As shown in fig. 3 to 4, wherein fig. 4 is a schematic cross-sectional structure diagram at B-B' in fig. 3, the present embodiment provides a high-power vcsel with a light-emitting area, and a basic structure of the vcsel is as in embodiment 1, wherein the vcsel has a back-emitting structure, and the vcsel includes: a P-type conductive lower mirror 211, a back surface of the P-type conductive lower mirror 211 having a lower electrode structure 107; an active layer 109 on the P-type conductive lower mirror 211; an N-type conductive upper mirror 208 on the active layer 109, the N-type conductive upper mirror 208 having a current confinement layer 110 therein, the current confinement layer 110 defining the emission hole 10; a substrate 106 located above the N-type conductive upper mirror 208; a dielectric layer 112 formed on the substrate 106; an isolation trench 101, wherein the isolation trench 101 extends from the substrate 106 into the P-type conductive lower mirror 211 to partially isolate the emission hole 10 to form an elongated emission region 100, and the P-type conductive lower mirror 211, the active layer 109 and the N-type conductive upper mirror 208 of the elongated emission region 100 are communicated; an insulating layer 102 formed on the bottom and sidewalls of the isolation trench 101; and a conductive layer 103 filled in the isolation trench 101, wherein the conductive layer 103 extends to the elongated emitter region 100 towards two sides of the isolation trench 101 and forms an ohmic contact with the substrate 106 in the elongated emitter region 100. The conductive layer 103 includes a stacked structure of an Au layer, a Ge layer, a Ni layer, and an Au layer stacked in this order, and the Au layer can form a good ohmic contact with the N-type substrate 106. Of course, the conductive layer 103 may be formed of other metal stacked layers, and is not limited to the examples listed herein. The vertical cavity surface emitting laser of the present embodiment adopts a back surface emitting structure, which can reduce the area occupied by the current confinement layer 110 and improve the integration level of the device.
Example 3
As shown in fig. 5 to 6, wherein fig. 6 is a schematic cross-sectional structure view at C-C' in fig. 5, the present embodiment provides a high-power vcsel with a light-emitting area, and a basic structure of the vcsel is as in embodiment 1, wherein the vcsel has a back-emitting structure, and the vcsel includes: a P-type conductive lower mirror 211, a back surface of the P-type conductive lower mirror 211 having a lower electrode structure 107; an active layer 109 on the P-type conductive lower mirror 211; an N-type conductive upper mirror 208 on the active layer 109, the N-type conductive upper mirror 208 having a current confinement layer 110 therein, the current confinement layer 110 defining the emission hole 10; a substrate 106 located on the N-type conductive upper mirror 208, wherein the substrate 106 located in the area of the emission hole 10 is removed to form an emission cavity so as to expose the N-type conductive upper mirror 208; a dielectric layer 112 formed on the exposed N-type conductive upper mirror 208; an isolation trench 101, wherein the N-type conductive upper mirror 208 exposed from the emission cavity of the isolation trench 101 extends into the P-type conductive lower mirror 211 to partially isolate the emission hole 10 to form an elongated emission region 100, and the P-type conductive lower mirror 211, the active layer 109 and the N-type conductive upper mirror 208 of the elongated emission region 100 are communicated; an insulating layer 102 formed on the bottom and sidewalls of the isolation trench 101; and a conductive layer 103 filled in the isolation trench 101, wherein the conductive layer 103 extends to the elongated emission region 100 towards two sides of the isolation trench 101 and forms an ohmic contact with the N-type conductive upper mirror 208 in the elongated emission region 100. The conductive layer 103 includes a stacked structure of an Au layer, a Ge layer, a Ni layer, and an Au layer stacked in this order, and the Au layer can form a good ohmic contact with the N-type substrate 106. Of course, the conductive layer 103 may be formed of other metal stacked layers, and is not limited to the examples listed herein. The vertical cavity surface emitting laser of the present embodiment adopts a back surface emitting structure, which can reduce the area occupied by the current confinement layer 110 and improve the integration level of the device, and in the present embodiment, part of the substrate 106 is removed in the region of the emitting hole 10 to form an emitting cavity, which can reduce the loss of emitted light and improve the emitting power.
Example 4
As shown in fig. 7, the present embodiment provides a high power vcsel with a monolithic light emitting structure, which has a basic structure as in embodiment 1, wherein the difference from embodiment 1 is that the elongated emitting regions 200 are arranged in a spiral shape, and the elongated emitting regions 200 are separated by spiral-shaped isolation trenches 201. The vertical cavity surface emitting laser of the embodiment can obtain 360-degree symmetric emitted laser, and the application range of the vertical cavity surface emitting laser is expanded.
Example 5
As shown in fig. 8, this embodiment provides a light-emitting-area-integrated high-power vcsel as in embodiment 1, wherein the basic structure is different from that of embodiment 1 in that the elongated emitting area includes a first elongated emitting connection area 320 and a second elongated emitting connection area 321 which intersect perpendicularly to each other, so as to divide the emitting hole 10 into four quadrant areas, each of the quadrant areas further includes a plurality of elongated emitting tooth-shaped areas 322 connected to the first elongated emitting connection area 320 and the second elongated emitting connection area 321, and the elongated emitting tooth-shaped areas 322 in any two adjacent quadrant areas are connected to different elongated emitting connection areas and are perpendicular to each other.
As described above, the high-power vertical cavity surface emitting laser with a light emitting region of the present invention has the following advantages:
according to the invention, the emission hole of the vertical cavity surface emitting laser with the large oxidation aperture is isolated into the long and narrow emission region through the isolation groove and the conductive layer arranged in the isolation groove, and the long and narrow emission region is in contact with the conductive layer in the isolation groove, so that on one hand, a current path in the emission hole is increased, the current density of the middle region of the vertical cavity surface emitting laser with the large oxidation aperture can be effectively increased, on the other hand, the current can be transversely transmitted from the conductive layer, the uniformity of the current density distribution in the emission hole is greatly improved, and the conversion efficiency is improved, and the conversion efficiency of the vertical cavity surface emitting laser can be as high as 30-50%.
The long and narrow emitting regions are positioned in the same emitting hole and communicated with each other, and have coherence and emergent light coherence. Can be matched with a Diffraction Optical Element (DOE), thereby being capable of remarkably improving the signal-to-noise ratio of the vertical cavity surface emitting laser. Meanwhile, the coherence of emergent light is kept in a large range. The invention can be applied to the fields of laser radar, infrared cameras, depth recognition detectors and the like.
The invention can effectively improve the power density of the vertical cavity surface emitting laser, namely, the power of the laser or the laser array in unit area, can reduce the number of the required lasers under the same optical power requirement, can substantially improve the integration level of a chip, and effectively reduce the cost of the chip.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (18)
1. A vertical cavity surface emitting laser with a monolithic light emitting region, said vertical cavity surface emitting laser comprising:
the emitting hole is internally provided with an isolation groove which isolates the emitting hole part to form a long and narrow emitting region, and the long and narrow emitting regions in the emitting hole are all communicated to form a one-body emitting region;
the insulating layer is formed at the bottom and the side wall of the isolation groove; and
and the conductive layer is filled in the isolation groove, extends to the long and narrow emission region towards two sides of the isolation groove and forms ohmic contact with the long and narrow emission region.
2. The high power VCSEL of claim 1, wherein: the width of the long and narrow emission region is between 5 micrometers and 50 micrometers.
3. The high power VCSEL of claim 1, wherein: the width of the isolation groove is between 2 and 10 microns.
4. The high power VCSEL of claim 1, wherein: the long and narrow emission regions are arranged in a fishbone shape and comprise long and narrow emission connecting regions and a plurality of long and narrow emission tooth-shaped regions connected to two sides of the long and narrow emission connecting regions, and the long and narrow emission tooth-shaped regions are spaced by the isolation grooves.
5. The high power VCSEL of claim 1, wherein: the long and narrow emission regions are arranged in a spiral shape and are spaced by spiral isolation grooves.
6. The high power VCSEL of claim 1, wherein: the long and narrow emission region comprises a first long and narrow emission connection region and a second long and narrow emission connection region which are vertically crossed so as to cut the emission hole into four quadrant regions, each quadrant region further comprises a plurality of long and narrow emission tooth-shaped regions which are respectively connected to the first long and narrow emission connection region and the second long and narrow emission connection region, and the long and narrow emission tooth-shaped regions in any two adjacent quadrant regions are connected to different long and narrow emission connection regions and are perpendicular to each other.
7. The high power VCSEL of claim 1, wherein: the radial width of the emission hole is not less than 50 microns.
8. The high power VCSEL of claim 1, wherein: the vertical cavity surface emitting laser further comprises an upper electrode structure, the upper electrode structure surrounds the emitting hole, and the conductive layer is connected to the upper electrode structure.
9. The high power VCSEL of claim 1, wherein: the vertical cavity surface emitting laser is of a front surface emitting structure, and includes:
the back surface of the substrate is provided with a lower electrode structure;
an N-type conductive lower mirror located over the substrate;
an active layer located over the N-type conductive lower mirror;
a P-type conductive upper mirror located above the active layer, the P-type conductive upper mirror having a current confinement layer therein and the emission aperture being defined by the current confinement layer;
a dielectric layer located over the P-type conductive upper mirror;
an isolation trench extending from the P-type conductive upper mirror into the N-type conductive lower mirror to isolate the emission hole portion to form an elongated emission region, wherein the P-type conductive upper mirror, the active layer, and the N-type conductive lower mirror of the elongated emission region are connected;
the insulating layer is formed at the bottom and the side wall of the isolation groove; and
and the conductive layer is filled in the isolation groove, extends to the long and narrow emission region towards two sides of the isolation groove and forms ohmic contact with the P-type conductive upper reflecting mirror in the long and narrow emission region.
10. The high power VCSEL of claim 9, wherein: the conductive layer comprises a laminated structure consisting of a Ti layer, a Pt layer and an Au layer which are sequentially laminated.
11. The high power VCSEL of claim 1, wherein: the vertical cavity surface emitting laser is a back surface emitting structure, and includes:
the back surface of the P-type conductive lower reflecting mirror is provided with a lower electrode structure;
an active layer located over the P-type conductive lower mirror;
an N-type conductive upper mirror located above the active layer, the N-type conductive upper mirror having a current confinement layer therein and the emission aperture being defined by the current confinement layer;
a substrate located over the N-type conductive upper mirror;
a dielectric layer formed on the substrate;
an isolation trench extending from the substrate into the P-type conductive lower mirror to partially isolate the emission hole to form an elongated emission region, wherein the P-type conductive lower mirror, the active layer and the N-type conductive upper mirror of the elongated emission region are in communication;
the insulating layer is formed at the bottom and the side wall of the isolation groove; and
and the conductive layer is filled in the isolation groove, extends to the long and narrow emission region towards two sides of the isolation groove and forms ohmic contact with the substrate in the long and narrow emission region.
12. The high power vcsel of claim 11, wherein: the conducting layer comprises a laminated structure consisting of an Au layer, a Ge layer, a Ni layer and an Au layer which are sequentially laminated.
13. The high power VCSEL of claim 1, wherein: the vertical cavity surface emitting laser is a back surface emitting structure, and includes:
the back surface of the P-type conductive lower reflecting mirror is provided with a lower electrode structure;
an active layer located over the P-type conductive lower mirror;
an N-type conductive upper mirror located above the active layer, the N-type conductive upper mirror having a current confinement layer therein and the emission aperture being defined by the current confinement layer;
the substrate is positioned above the N-type conductive upper reflecting mirror, and the substrate positioned in the emitting hole area is removed to form an emitting cavity so as to expose the N-type conductive upper reflecting mirror;
the dielectric layer is formed on the exposed N-type conductive upper reflecting mirror;
the isolation groove extends from the N-type conductive upper reflecting mirror exposed out of the emission cavity into the P-type conductive lower reflecting mirror to isolate the emission hole part to form an elongated emission region, and the P-type conductive lower reflecting mirror, the active layer and the N-type conductive upper reflecting mirror of the elongated emission region are communicated;
the insulating layer is formed at the bottom and the side wall of the isolation groove; and
and the conductive layer is filled in the isolation groove, extends to the long and narrow emission region towards two sides of the isolation groove and forms ohmic contact with the N-type conductive upper reflecting mirror in the long and narrow emission region.
14. The monolithic light emitting area high power vertical cavity surface emitting laser of claim 13, wherein: the conducting layer comprises a laminated structure consisting of an Au layer, a Ge layer, a Ni layer and an Au layer which are sequentially laminated.
15. The integrally light-emitting-region high-power vertical cavity surface emitting laser according to any one of claims 9 to 14, wherein: the current confinement layer includes one of an air column type current confinement structure, an ion injection type current confinement structure, a buried heterojunction type current confinement structure, and an oxidation confinement type current confinement structure.
16. A lidar characterized in that a high-power vertical cavity surface emitting laser with a body light emitting area according to any one of claims 1 to 15 is adopted as a light source of the lidar.
17. An infrared camera is characterized in that a light source of the infrared camera adopts a high-power vertical cavity surface emitting laser with an integral luminous area as claimed in any one of claims 1 to 15.
18. A 3D depth recognition detector, wherein the light source of the depth recognition detector is the high-power vertical cavity surface emitting laser with a light emitting area according to any one of claims 1 to 15.
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| CN111370996A (en) * | 2020-03-20 | 2020-07-03 | 北京嘉圣光通科技有限公司 | Vertical cavity surface emitting laser |
| CN116231452B (en) * | 2023-05-05 | 2023-08-15 | 江西德瑞光电技术有限责任公司 | Vcsel chip and preparation method thereof |
| CN116387980B (en) * | 2023-06-07 | 2023-08-25 | 深圳市柠檬光子科技有限公司 | Vertical cavity surface emitting laser and electronic device |
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| JP4050028B2 (en) * | 2001-09-28 | 2008-02-20 | 株式会社東芝 | Surface emitting semiconductor light emitting device |
| JP4062983B2 (en) * | 2002-06-20 | 2008-03-19 | 富士ゼロックス株式会社 | Surface emitting semiconductor laser and manufacturing method thereof |
| CN100456584C (en) * | 2006-08-02 | 2009-01-28 | 长春理工大学 | Multi-core electric filling structure for large out light hole vertical cavity surface emitting semiconductor laser |
| CN101510666A (en) * | 2009-04-07 | 2009-08-19 | 中国科学院长春光学精密机械与物理研究所 | Method for etching non-closed annular groove of preparation of vertical cavity surface emission semiconductor laser |
| CN106936069A (en) * | 2015-12-30 | 2017-07-07 | 中国科学院苏州纳米技术与纳米仿生研究所 | A kind of surface-emitting laser and preparation method thereof |
| JP6380512B2 (en) * | 2016-11-16 | 2018-08-29 | 富士ゼロックス株式会社 | Light emitting element array and optical transmission device |
| CN106654857A (en) * | 2017-03-05 | 2017-05-10 | 北京工业大学 | High-beam-quality large-scale VCSEL in-phase coupled array |
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