CN118630576A - Vertical cavity surface emitting laser for high-speed communication and preparation method thereof - Google Patents
Vertical cavity surface emitting laser for high-speed communication and preparation method thereof Download PDFInfo
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Abstract
The invention provides a vertical cavity surface emitting laser for high-speed communication and a preparation method thereof. The vertical cavity surface emitting laser includes an epitaxial wafer, an oxide layer, an electrically insulating region, a dielectric layer, and a P, N metal layer. The vertical cavity surface emitting laser structure satisfies that 1, the epitaxial wafer comprises a resonant cavity with the total thickness of 1/2 times of the optical wavelength. An oxide layer is formed over the active region in the cavity. 2. The electrically insulating region is formed by ion implantation and is formed from top to bottom below the active region in the resonant cavity. 3. The relief structure described in the above embodiment is provided near the light exit hole; the matching of the three structural characteristics can realize a single-mode vertical cavity surface laser for high-speed modulation. The relief structure is etched through the surface of the light emergent hole, and the medium area and the non-medium area which are arranged at intervals provide integrally different reflectivities, so that the filtering of the high-order mode is realized, and the single-mode output is formed.
Description
Technical Field
The invention relates to the technical field of semiconductor chips, in particular to a vertical cavity surface emitting laser for high-speed communication and a preparation method thereof.
Background
VCSELs (Vertical-Cavity Surface-EMITTING LASER), an acronym for Vertical Cavity Surface emitting lasers. This concept was first proposed in 1977 by the university of tokyo industry, japan, by He Jianyi (KENICHI IGA) et al, which has been technically precipitated and innovated for over forty years. The VCSEL has the remarkable advantages of low threshold value, small far-field divergence angle, high modulation rate, easiness in realizing single longitudinal mode operation, excellent two-dimensional integration and the like, and has been widely applied to a plurality of fields such as broadband Ethernet, high-speed data communication, optical interconnection, three-dimensional sensing, optical integrated elements and the like and has practical value through technical development for many years.
Compared with the edge-emitting semiconductor laser, the laser resonator of the VCSEL is short, and the light-emitting surface is large, so that the VCSEL has been used as a multimode laser for a long time. The resonant cavity is short, so that the formed FP cavity has large longitudinal mode spacing, and generally only one longitudinal mode is excited. The light-emitting surface is large, and the number of modes of transverse lasing is large, so that the light-emitting surface is multi-transverse mode. And the so-called "multimode" for general short refers to multiple transverse modes.
Single mode lasers are required in particular fields, such as sensing, to provide better signal-to-noise ratios and to have less transmission dispersion induced bit errors in long range data transmission. Single mode VCSELs have been one of many directions of evolution for VCSELs. Traditionally, single mode VCSELs can be obtained by reducing the diameter of the light emitting region below 3-4 microns, which however greatly reduces the light output of the device, the rapid increase in resistance due to the excessively small light emitting aperture is detrimental to high frequency modulation, and the excessively small light emitting aperture also presents a significant challenge for mass production.
To reduce the number of transverse modes, this can be achieved by increasing the cavity length of the VCSEL cavity. The increased laser cavity increases the loss encountered by each mode in creating resonance, while the loss encountered by the fundamental film is minimal, defeating mode competition, thereby achieving single mode output. However, in high-speed data communication VCSELs, excessively long resonant cavities can increase photon lifetime, thereby greatly limiting the frequency bandwidth and modulation rate of the device. The shortened resonant cavity can improve the speed, however, the multi-mode is formed by processing according to the normal process, which is unfavorable for long-distance transmission.
Disclosure of Invention
The invention aims to provide a vertical cavity surface emitting laser for high-speed communication and a preparation method thereof. The vertical cavity surface emitting laser for high-speed communication provided by the invention is improved by epitaxy and a process at the same time, so that the VCSEL device which has single-mode output and can be used for high-speed communication is formed, and the application of the VCSEL in the field of data communication is facilitated to be expanded. The vertical cavity surface emitting laser for high-speed communication provided by the invention can be used for an emitting light source of a high-speed optical module of 400G/800G/1.6T. Compared with the traditional short-distance data communication with a transmission distance smaller than 500 meters, the vertical cavity surface emitting laser for high-speed communication provided by the invention can be used for high-speed optical interconnection of more than 500-2000 meters.
In a first aspect, the present invention provides a vertical cavity surface emitting laser for high speed communications. A vertical cavity surface emitting laser for high speed communications comprising:
Epitaxial wafer, epitaxial wafer includes: the device comprises a substrate, an N-type Bragg reflector, a resonant cavity, an active region formed in the resonant cavity and a P-type Bragg reflector which are sequentially arranged from bottom to top;
an oxide layer formed in the cavity over the active region;
an electric insulation region formed after ion implantation, wherein the electric insulation region is formed below the active region in the resonant cavity from top to bottom;
A dielectric layer formed on the epitaxial wafer; and
A P metal layer formed on the epitaxial wafer;
Wherein the total thickness of the resonant cavity is 1/2 times of the optical wavelength;
The vertical cavity surface emitting laser further comprises a light outlet hole, wherein the light outlet hole is formed on the P-type Bragg reflector, and the diameter of the light outlet hole is larger than that of the oxidation hole;
the light emergent hole is provided with a relief structure, the relief structure is formed by partially etching the surface of the dielectric layer, and the relief structure is provided with a non-dielectric region and a dielectric region;
The dielectric region includes: the first medium region, the second medium region and the third medium region;
The non-dielectric region includes: a first non-dielectric region and a second non-dielectric region;
The first non-medium area is arranged between the first medium area and the second medium area; the second non-medium region is arranged between the second medium region and the third medium region;
the first dielectric region is solid and round, and a straight line formed by connecting the center of the first dielectric region and the center of the oxidation hole is perpendicular to the extension plane where the substrate is positioned; the diameter of the first medium region is smaller than the diameter of the oxidation hole;
the second medium area is annular, and the center of the inner circle and the center of the outer circle of the second medium area are overlapped with the center of the first medium area; the ring width of the second medium region is the first width;
the third medium region is annular, and the center of the inner circle and the center of the outer circle of the third medium region are overlapped with the center of the first medium region; the annular width of the third medium region is a second width;
The first width is greater than the second width;
The first dielectric region has a diameter greater than the first width.
Further, the first non-dielectric region and the second non-dielectric region are both annular;
the annular width of the first non-medium area is a third width;
the annular width of the second non-medium area is a fourth width;
the third width is greater than the fourth width.
Further, the diameter of the oxidation holes is 6 micrometers to 10 micrometers.
Further, the diameter of the oxidation hole is 7 microns, and the diameter of the first medium region is 5 microns;
the first width is 3 microns and the second width is 2 microns.
Further, the dielectric region is made of silicon nitride.
Further, the electric insulation region starts from the P-type Bragg reflector and performs ion implantation downwards to the resonant cavity, the implantation depth of the electric insulation region reaches below the active region, the electric insulation region is used for limiting the current which is injected into the vertical cavity surface emitting laser through the P surface to a central region, and the central region is the region where the oxidation hole and the light emitting hole are located.
In a second aspect, the present invention provides a method for manufacturing a vertical cavity surface emitting laser for high-speed communication, the method for manufacturing a vertical cavity surface emitting laser for high-speed communication comprising:
S1, forming an epitaxial wafer on a wafer, wherein the epitaxial wafer comprises: the device comprises a substrate, an N-type Bragg reflector, a resonant cavity, an active region formed in the resonant cavity and a P-type Bragg reflector which are sequentially arranged from bottom to top; wherein the total thickness of the resonant cavity is 1/2 times of the optical wavelength;
S2, after the growth of the epitaxial wafer is completed, carrying out P metal layer deposition;
s3, depositing a dielectric layer by adopting a plasma enhanced chemical vapor deposition method, wherein the dielectric layer is used for protecting the P metal layer and the epitaxial wafer;
s4, forming a pit by adopting an inductively coupled plasma-reactive ion etching method, wherein the pit exposes the side wall which needs wet oxidation;
S5, forming an oxide layer by wet oxidation above the active region, wherein the oxide layer comprises an oxide hole, and the diameter of the oxide hole is D0; in the resonant cavity, an epitaxial material above the active region is an Al xGa1-x As material, wherein x=0.98-0.99,6 micrometers is less than or equal to D0 and less than or equal to 10 micrometers;
S6, performing ion implantation after adopting photoresist to protect the light-emitting area and part of the metal contact area so as to form an electric insulation area, wherein the electric insulation area is formed below the active area in the resonant cavity from top to bottom in the epitaxial wafer;
s7, depositing a dielectric layer on the side wall of the pit by adopting a plasma enhanced chemical vapor deposition method;
s8, defining a light outlet hole of the vertical cavity surface emitting laser on the dielectric layer, defining an etching pattern of a relief structure through photoetching, and further etching the dielectric layer at the light outlet hole to form the relief structure;
wherein the diameter of the light emergent hole is larger than that of the oxidation hole; the relief structure has a non-dielectric region and a dielectric region;
The dielectric region includes: the first medium region, the second medium region and the third medium region;
The non-dielectric region includes: a first non-dielectric region and a second non-dielectric region;
The first non-medium area is arranged between the first medium area and the second medium area; the second non-medium region is arranged between the second medium region and the third medium region;
the first dielectric region is solid and round, and a straight line formed by connecting the center of the first dielectric region and the center of the oxidation hole is perpendicular to the extension plane where the substrate is positioned; the diameter of the first medium region is smaller than the diameter of the oxidation hole;
the second medium area is annular, and the center of the inner circle and the center of the outer circle of the second medium area are overlapped with the center of the first medium area; the ring width of the second medium region is the first width;
the third medium region is annular, and the center of the inner circle and the center of the outer circle of the third medium region are overlapped with the center of the first medium region; the annular width of the third medium region is a second width;
The first width is greater than the second width;
The diameter of the first medium region is larger than the first width;
s9, manufacturing an N metal layer and splitting to form a plurality of vertical cavity surface emitting lasers.
Further, in S6, the ion implantation species and dose include:
An H+ ion with an implantation energy of 410keV and a dose of 5E+13, an H+ ion with an implantation energy of 360keV and a dose of 4E+13, an H+ ion with an implantation energy of 300keV and a dose of 3.5E+14, an H+ ion with an implantation energy of 230keV and a dose of 3.5E+14, an H+ ion with an implantation energy of 100keV and a dose of 4E+14, and an H+ ion with an implantation energy of 20keV and a dose of 4E+14.
Further, in S1, the step of forming the epitaxial wafer includes:
S11, growing an N-type Bragg reflector on an N-type substrate by utilizing an organic metal chemical vapor deposition method or a molecular beam epitaxy method, wherein the N-type Bragg reflector comprises an Al xGa(1-x) As material which is formed by alternately growing a high-refractive-index material and a low-refractive-index material, x=x 1 in the high-refractive-index material and 0.05< x 1 <0.2 is met, x=x 2 in the low-refractive-index material and 0.8< x 2 <0.95 is met, and the thickness of each layer of Al xGa(1-x) As material is one fourth of the optical thickness;
S12, forming a resonant cavity on the surface of the N-type Bragg reflector, wherein the resonant cavity comprises an Al GaAs body material with gradually changed aluminum components;
S13, after the resonant cavity is formed to be more than 1 micrometer thick, depositing the active region, wherein the active region comprises a plurality of groups of strain quantum wells containing I nGaAs and Al GaAs and is used for generating gain required by laser, and the active region is formed at 1/2 position in the resonant cavity; after the deposition of the active region is completed, further growing the residual thickness of the resonant cavity;
S14, forming a P-type Bragg reflector above the resonant cavity to complete the growth of the epitaxial wafer; wherein the P-type bragg mirror comprises an Al yGa(1-y) As material grown alternately of a high refractive index material and a low refractive index material, wherein y=y 1 in the high refractive index material and satisfies 0.05< y 1 <0.2, y=y 2 in the low refractive index material and satisfies 0.8< y 2 <0.9, and each layer of Al yGa(1-y) As material has a quarter optical thickness.
Further, after forming the electrically insulating region in S6, the step of S9 includes:
s91, manufacturing a polymer material layer, and further depositing a dielectric layer for protecting the surface and the side wall by adopting an ion enhanced chemical vapor deposition method after the polymer material layer is manufactured; the polymer material layer is positioned below the P metal layer;
S92, carrying out P-surface hole opening and front gold plating to form a gold electrode on the P metal layer;
s93, etching the step on the N surface, evaporating alloy materials to form a front N metal layer, and further depositing a dielectric layer for protecting the surface and the side wall by adopting an ion enhanced chemical vapor deposition method after the front N metal layer is manufactured;
s94, thinning the surface of the substrate far away from the N-type Bragg reflector, and further performing back alloy evaporation to form a back N metal layer;
s95, splitting the wafer to form a plurality of vertical cavity surface emitting lasers with different emergent light powers.
The invention has at least the following advantages or beneficial effects:
1. in the resonant cavity of the vertical cavity surface emitting laser for high-speed communication, the resonant cavity with the total thickness of 1/2 times of optical wavelength is utilized, the service life of photons is reduced by shortening the resonant cavity to 1/2 times of optical wavelength, and the response bandwidth of the vertical wall surface laser is increased, so that the speed is improved.
2. The electrically insulating regions of the present invention are formed by ion implantation. The electric insulation area is formed below the active area in the resonant cavity from top to bottom, so that the injection diameter of current can be effectively limited, and excitation of a high-order mode is reduced. The size of the electrically isolated region can also affect to some extent the current injection of the VCSEL for high speed communications. The electric insulation area is used for limiting the current injected into the vertical cavity surface emitting laser through the P surface to a central area, and the central area is the area where the oxidation hole and the light emergent hole are located. Limiting the current injected into the VCSEL through the P-plane to the central region, wherein the current has the highest spatial overlap with the LP01 fundamental mode, thereby reducing the excitation of the higher-order modes.
3. According to the invention, the relief structure is etched on the surface of the light emergent hole, and the high-order mode is filtered, so that single-mode output is formed. The relief structure includes dielectric and non-dielectric regions spaced apart from each other to provide overall different reflectivity for mode selection. The specific medium area comprises a first medium area arranged in the center of the light outlet, the first medium area can provide optimal reflectivity, the coincidence degree of the first medium area and the fundamental mode emergent light of the vertical cavity surface laser for high-speed communication is high, and the fundamental mode light can be well excited.
4. The main structural characteristics of the invention include that the epitaxial wafer comprises a resonant cavity with the total thickness of 1/2 times of the optical wavelength. An oxide layer is formed on the active region in the resonant cavity; 2. the electric insulation region is formed by ion implantation, and the electric insulation region is formed below the active region in the resonant cavity from top to bottom; 3. the relief structure described in the above embodiment is provided near the light exit hole; the cooperation of the three structural features can realize a single-mode vertical cavity surface laser for high-speed modulation.
5. The invention also provides a preparation method of the vertical cavity surface laser for high-speed communication, and the vertical cavity surface laser for high-speed communication has the following three structural characteristics: 1. the epitaxial wafer comprises a resonant cavity with a total thickness of 1/2 times the optical wavelength. An oxide layer is formed on the active region in the resonant cavity; 2. the electric insulation region is formed by ion implantation, and the electric insulation region is formed below the active region in the resonant cavity from top to bottom; 3. the relief structure described in the above embodiment is provided near the light exit hole; the matching of the three structural characteristics can realize a single-mode vertical cavity surface laser for high-speed modulation. Experiments prove that the single-mode vertical cavity surface laser for high-speed modulation can be realized only by adopting the special relief structure in the technical scheme of the invention and matching with the shortened resonant cavity and assisting ion implantation. Specifically, the relief structure is etched through the surface of the light emitting hole, and the medium area and the non-medium area which are arranged at intervals provide integrally different reflectivities, so that the filtering of the high-order mode is realized, and the single-mode output is formed.
In the above, the vertical cavity surface emitting laser for high-speed communication formed in the present invention the vertical cavity surface emitting laser for high-speed communication provided in the present invention can be used for an emission light source of a high-speed optical module of 400G/800G/1.6T. Compared with the traditional short-distance data communication with a transmission distance smaller than 500 meters, the vertical cavity surface emitting laser for high-speed communication provided by the invention can be used for high-speed optical interconnection of more than 500-2000 meters.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a vertical cavity surface emitting laser for high-speed communication according to an embodiment of the present invention;
FIG. 2 is a schematic top view of a relief structure of a VCSEL for high speed communication according to an embodiment of the present invention;
FIG. 3 is a graph comparing the performance of a VCSEL for high speed communication according to an embodiment of the present invention with a device performance test in the prior art;
FIG. 4 is a graph of the spectral test effect of a VCSEL of the prior art;
fig. 5 is a spectrum test effect diagram of a vertical cavity surface emitting laser for high-speed communication according to an embodiment of the present invention.
Icon description
Vertical cavity surface emitting laser 100 for high speed communication:
epitaxial wafer 110: a substrate 10, an N-type Bragg reflector 20, a resonant cavity 30, an active region 31, and a P-type Bragg reflector 40;
oxide layer 50, electrically insulating region 60, dielectric layer 70, and layer 80 of polymeric material;
Relief structure 90:
dielectric region 91, first dielectric region 91a, second dielectric region 91b, third dielectric region 91c;
A non-dielectric region 92, a first non-dielectric region 92a, a second non-dielectric region 92b;
a P metal layer 120; a front side N metal layer 131; a backside N-metal layer 132.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
Referring to fig. 1, the present invention provides an optical module for high-speed communication, which is a vertical cavity surface emitting laser 100 for high-speed communication. The vertical cavity surface emitting laser 100 for high-speed communication includes: epitaxial wafer 110, oxide layer 50, electrically insulating region 60, dielectric layer 70, polymer material layer 80, P-metal layer 120, front side N-metal layer 131, and back side N-metal layer 132. The VCSEL 100 for high speed communications further includes a relief structure 90, the particular structure of the relief structure 90 in one embodiment being shown in FIG. 2. A top view of the vicinity of the light exit aperture of a vertical cavity surface emitting laser 100 for high speed communication is illustrated in fig. 2.
Wherein an oxide layer 50 is formed in the cavity 30 over the active region 31. The electrically insulating region 60 is formed by ion implantation. The formation of the electrically insulating region 60 from top to bottom below the active region 31 in the cavity 30 effectively limits the injection diameter of the current, thereby reducing excitation of higher order modes. The size of the electrically insulating region 60 also affects to some extent the current injection of the VCSEL for high speed communications. In this embodiment, the electrically insulating region 60 is used to limit the current injected into the vcsels 100 through the P-plane to a central region, which is the region where the oxide holes and the light exit holes are located. Limiting the current injected through the P-plane into the vcsels 100 to the central region, with the highest spatial overlap of the current with the LP01 fundamental mode, can reduce excitation of higher order modes.
The dielectric layer 70 is formed on the epitaxial wafer 110, for example, on the top surface of the P-type bragg reflector 40, the side surface of a part of the structural layer of the epitaxial wafer 110, and a part of the surface of the substrate 10. The material of dielectric layer 70 may be selected from silicon nitride, silicon carbide, or silicon dioxide. The P-metal layer 120 is formed on the epitaxial wafer 110, and the P-metal layer 120 may further include: p-type contact metal and gold plating. The P-metal layer 120 serves as the P-electrode of the vertical cavity surface emitting laser for high speed communication.
Wherein the total thickness of the cavity 30 is 1/2 times the optical wavelength. A typical VCSEL device contains 1 resonant cavity with a thick optical wavelength. According to the technical scheme, the resonant cavity 30 with the total thickness of 1/2 times of the optical wavelength is utilized, the service life of photons is reduced, and the response bandwidth of the vertical wall laser is increased by shortening the resonant cavity 30 to 1/2 times of the optical wavelength, so that the speed is increased.
The vertical cavity surface laser 100 for high-speed communication further includes light emitting holes for emitting light disposed between the P-metal layers 120 disposed at intervals. The light exit holes are formed on the P-type bragg reflector 40, and as shown in fig. 1, the diameter of the light exit holes is larger than that of the oxidized holes.
The light exit aperture is provided with a relief structure 90, the relief structure 90 being formed by partially etching the surface of the dielectric layer, see in particular fig. 2, the relief structure 90 having a dielectric region 91 and a non-dielectric region 92. The medium region 91 includes: a first dielectric region 91a, a second dielectric region 91b, and a third dielectric region 91c. The non-dielectric region 92 includes: a first non-dielectric region 92a and a second non-dielectric region 92b.
A first non-dielectric region 92a is provided between the first dielectric region 91a and the second dielectric region 91 b. A second non-dielectric region 92b is provided between the second dielectric region 91b and the third dielectric region 91 c. The first dielectric region 91a is solid and circular, and a straight line formed by connecting the center of the first dielectric region 91a and the center of the oxidation hole is perpendicular to the extension plane where the substrate is located. The diameter D1 of the first dielectric region 91a is smaller than the diameter D0 of the oxidation hole. The second medium region 91b is annular, and the center of the inner circle and the center of the outer circle of the second medium region 91b are coincident with the center of the first medium region 91 a. The loop width of the second dielectric region 91b is the first width. The first width is obtained by subtracting the inner diameter D21 of the second medium region 91b from the outer diameter D22 of the second medium region 91 b. The third medium region 91c is annular, and the center of the inner circle and the center of the outer circle of the third medium region 91c are coincident with the center of the first medium region 91 a. The loop width of the third dielectric region 91c is the second width. The second width is obtained by subtracting the inner diameter D31 of the third medium region 91c from the outer diameter D32 of the third medium region 91 c.
The first width is greater than the second width. The diameter of the first dielectric region 91a is greater than the first width.
In this embodiment, the relief structure 90 is etched through the surface of the light exit hole, and the high order modes are filtered, so as to form a single mode output. The relief structure 90 includes dielectric regions 91 and non-dielectric regions 92 spaced apart from each other to provide overall different reflectivity for mode selection. The specific dielectric region 91 includes a first dielectric region 91a disposed in the center of the light exit hole, where the first dielectric region 91a can provide an optimal reflectivity, and the first dielectric region 91a has a high overlap ratio with the fundamental mode light of the vertical cavity surface laser 100 for high-speed communication, so that the fundamental mode light can be well excited.
The first non-dielectric region 92a between the first dielectric region 91a and the second dielectric region 91b and the second non-dielectric region 92b between the second dielectric region 91b and the third dielectric region 91c each have a lower reflectivity. The primary intensity of the lasing light of the secondary higher order modes LP11/LP12/LP21 and higher order modes is distributed outside the first dielectric region 91a, and larger losses are encountered in the first and second non-dielectric regions 92a, 92b with lower reflectivity, so that the primary mode only can obtain lasing in the mode competition of the laser cavity. The diameter of the first dielectric region 91a is larger than the first width, and the first width is larger than the second width, so that the lasing of the fundamental mode can be better promoted, and the lasing of the second higher order mode and the lasing of the higher order mode can be better suppressed while the substructures of the dielectric region 91 and the non-dielectric region 92 meet the structural design.
In the embodiment of the invention, the epitaxial wafer comprises a resonant cavity with the total thickness of 1/2 times of the optical wavelength through 1. An oxide layer is formed on the active region in the resonant cavity; 2. the electric insulation region is formed by ion implantation, and the electric insulation region is formed below the active region in the resonant cavity from top to bottom; 3. the relief structure 90 of the above embodiment is disposed adjacent the light exit aperture; the cooperation of the above 3 modes can realize a single-mode vertical cavity surface laser for high-speed modulation.
Some of the prior art has a detailed structure near the light exit hole, but the improved effect of the prior art is to reduce the divergence angle, and the method is mainly used in the three-dimensional sensing field. What the present invention is to achieve is a single mode vertical cavity surface laser for high speed modulation where detailed structure is not possible only near the exit aperture (although the device may have a small divergence angle, but the rate is low). Therefore, a special relief structure 90 in the technical scheme of the present invention must be adopted, and a shortened resonant cavity is matched, so that the single-mode vertical cavity surface laser for high-speed modulation can be realized by auxiliary ion implantation.
In the embodiment of the present invention, by etching a specific surface relief structure 90 on the light exit surface of the vertical cavity surface laser 100 for high-speed communication, loss of the higher-order mode can be increased, and lasing of the fundamental mode can be promoted. The relief structure 90 referred to in this embodiment provides a relatively reduced specular reflectivity for higher order modes located near the first non-dielectric region 92a and the second non-dielectric region 92 b. By introducing the relief structure 90, the threshold gain of the higher order modes can be increased. In contrast, the base film is insensitive to the low reflectivity first and second non-dielectric regions 92a, 92b introduced by the relief structure 90, while the light of the next higher order modes and higher order modes is sensitive to the low reflectivity first and second non-dielectric regions 92a, 92b introduced by the relief structure 90, thereby enabling mode selection for obtaining a base mode output. In other words, since the fundamental mode is mainly located in the center (first dielectric region 91 a), the fundamental mode is not overlapped with the first non-dielectric region 92a and the second non-dielectric region 92b, so that the fundamental mode is less affected by the relief structure 90. The light field of the higher order mode overlaps the first non-medium region 92a and the second non-medium region 92b more largely at the non-central portion (non-first medium region 91 a), so that the light of the higher order mode is greatly affected by the relief structure 90, the attenuation is large, and the light of the higher order mode cannot be excited.
In one embodiment, the first non-dielectric region 92a and the second non-dielectric region 92b are both annular. The annular width of the first non-dielectric region 92a is the third width. The annular width of the second non-dielectric region 92b is the fourth width. The third width is greater than the fourth width.
In this embodiment, the specific structure of the first non-dielectric region 92a and the second non-dielectric region 92b can better suppress lasing in the next higher order mode and the higher order mode, so that only the fundamental mode in the vcsels 100 for high-speed communication can obtain lasing.
In one embodiment, the oxide holes in the oxide layer 50 have diameters between 6 microns and 10 microns, the optical field passes through the oxide aperture, the base film to surface relief structure 90 has a position diameter of about 4 microns to 7 microns, and the higher order mode diameter is larger, possibly up to 8 microns to 11 microns, and the relief structure 90 is provided in the present invention to provide overall different reflectivity, thereby enabling mode selection.
In one embodiment, the diameter D0 of the oxidation holes may be set to 7 microns. In another embodiment, the diameter D0 of the oxidation holes may be set to 8 microns. In yet another embodiment, the diameter D0 of the oxidation holes may be set to 9 microns. In yet another embodiment, the diameter D0 of the oxidation holes may be set to 10 microns.
In one embodiment, the diameter of the oxidized aperture is 7 microns and the diameter of the first dielectric region 91a is 5 microns. The first width is 3 microns and the second width is 2 microns. The diameter D1 of the first dielectric region 91a (which may be set to 5 micrometers, for example) is smaller than the diameter D0 of the oxide holes (which may be set to 7 micrometers). The second medium region 91b is annular, and the center of the inner circle and the center of the outer circle of the second medium region 91b are coincident with the center of the first medium region 91 a. The loop width of the second dielectric region 91b is the first width. The first width is the outer diameter D22 of the second dielectric region 91b (which may be set to 11 microns, for example) minus the inner diameter D21 of the second dielectric region 91b (which may be set to 8 microns, for example). The third medium region 91c is annular, and the center of the inner circle and the center of the outer circle of the third medium region 91c are coincident with the center of the first medium region 91 a. The loop width of the third dielectric region 91c is the second width. The second width is obtained by subtracting the inner diameter D31 (e.g., 13 μm) of the third medium region 91c from the outer diameter D32 (e.g., 15 μm) of the third medium region 91 c. The ion implantation region, i.e., the electrically insulating region 60, is located outside the diameter of 12um around the center of the first dielectric region 91 a.
In one embodiment, the material of dielectric layer 70 is silicon nitride.
In one embodiment, the electrically insulating region 60 begins with the P-type bragg mirror 40 and is implanted down to the resonant cavity 30, the implantation depth of the electrically insulating region 60 reaching below the active region 31, the electrically insulating region 60 being configured to confine the current injected through the P-plane into the vcsels 100 for high speed communications to a central region where the oxidation and light exit holes are located. The central region includes a laminated structure of regions where the oxide holes and the light exit holes are located, which is disposed between the back N-metal layer 132 and the P-metal layer 120.
In this embodiment, the electrically insulating region 60 is used to limit the current injected into the vcsels 100 through the P-plane to a central region, which is the region where the oxide holes and the light exit holes are located. Limiting the current injected through the P-plane into the vcsels 100 to the central region, with the highest spatial overlap of the current with the LP01 fundamental mode, can reduce excitation of higher order modes.
In one embodiment, active region 31 is located at 1/2 of the position in cavity 30 to facilitate lasing.
In another aspect of the present invention, a method for manufacturing a vertical cavity surface emitting laser 100 for high speed communication includes:
S1, forming an epitaxial wafer 110 on a wafer, the epitaxial wafer 110 including: the substrate 10, the N-type Bragg reflector 20, the resonant cavity 30, the active region 31 formed in the resonant cavity 30 and the P-type Bragg reflector 40 are sequentially arranged from bottom to top; wherein the total thickness of the cavity 30 is 1/2 times the optical wavelength.
In this step, a resonant cavity with a total thickness of 1/2 times the optical wavelength is set, and by shortening the resonant cavity 30 to 1/2 times the optical wavelength, the photon lifetime is reduced, and the response bandwidth of the vertical wall laser is increased, thereby improving the rate.
S2, after the growth of the epitaxial wafer 110 is completed, the P metal layer 120 is deposited, and the material of the P metal layer 120 can be T i/Pt/Au.
S3, depositing the dielectric layer 70 by adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, wherein the material of the dielectric layer 70 can be silicon nitride. The dielectric layer 70 is used to protect the P-metal layer 120 and the epitaxial wafer 110.
S4, forming a pit by adopting inductively coupled plasma-reactive ion etching (ICP-RI E etching), and exposing the side wall of the pit, which needs wet oxidation. The pit is used for wet oxidation in a subsequent step.
S5, introducing high-temperature steam into the wet oxidation furnace to carry out wet oxidation through the side wall of the pit: an oxide layer 50 is formed by wet oxidation over active region 31. The oxide layer 50 includes oxide holes having a diameter D0. The epitaxial material in the resonator 30 above the active region 31 is Al xGa1-x As material, where x=0.98 to 0.99,6 microns +.d0 +.10 microns.
S6, after the light-emitting area and part of the metal contact area are protected by photoresist, ion implantation is performed to form an electric insulation area 60. The electrically insulating region 60 is formed in the epitaxial wafer 110 from top to bottom below the active region 31 in the resonant cavity 30. The ion implantation region is an electrically insulating region 60 to provide a better current confinement region that helps suppress higher order modes.
And S7, depositing a dielectric layer 70 on the side wall of the pit by adopting a plasma enhanced chemical vapor deposition method. The material of dielectric layer 70 may be silicon nitride to protect the sidewalls.
S8, defining a light emitting hole of the vertical cavity surface emitting laser in the dielectric layer 70, defining an etching pattern of the relief structure 90 through photoetching, and further etching the dielectric layer 70 at the light emitting hole to form the relief structure 90. Wherein the relief structure 90 comprises dielectric regions 91 and non-dielectric regions 92. The dielectric region 91 includes a first dielectric region 91a, a second dielectric region 91b, and a third dielectric region 91c that are disposed at intervals. The non-dielectric region 92 includes a first non-dielectric region 92a and a second non-dielectric region 92b disposed at intervals.
A first non-dielectric region 92a is provided between the first dielectric region 91a and the second dielectric region 91 b. A second non-dielectric region 92b is provided between the second dielectric region 91b and the third dielectric region 91 c. The first dielectric region 91a is solid and circular, and a straight line formed by connecting the center of the first dielectric region 91a and the center of the oxidation hole is perpendicular to the extension plane where the substrate is located. The diameter D1 of the first dielectric region 91a is smaller than the diameter D0 of the oxidation hole. The second medium region 91b is annular, and the center of the inner circle and the center of the outer circle of the second medium region 91b are coincident with the center of the first medium region 91 a. The loop width of the second dielectric region 91b is the first width. The first width is obtained by subtracting the inner diameter D21 of the second medium region 91b from the outer diameter D22 of the second medium region 91 b. The third medium region 91c is annular, and the center of the inner circle and the center of the outer circle of the third medium region 91c are coincident with the center of the first medium region 91 a. The loop width of the third dielectric region 91c is the second width. The second width is obtained by subtracting the inner diameter D31 of the third medium region 91c from the outer diameter D32 of the third medium region 91 c.
The first width is greater than the second width. The diameter of the first dielectric region 91a is greater than the first width.
S9, manufacturing an N metal layer and splitting to form a plurality of vertical cavity surface emitting lasers 100 for high-speed communication.
In this embodiment, a method for manufacturing a vertical cavity surface laser 100 for high-speed communication is provided, and the vertical cavity surface laser 100 for high-speed communication has the following three structural characteristics: 1. the epitaxial wafer comprises a resonant cavity with a total thickness of 1/2 times the optical wavelength. An oxide layer is formed on the active region in the resonant cavity; 2. the electric insulation region is formed by ion implantation, and the electric insulation region is formed below the active region in the resonant cavity from top to bottom; 3. the relief structure 90 of the above embodiment is disposed adjacent the light exit aperture; the matching of the three structural characteristics can realize a single-mode vertical cavity surface laser for high-speed modulation. Experiments prove that the special relief structure 90 in the technical scheme of the invention is matched with a shortened resonant cavity, and the single-mode vertical cavity surface laser for high-speed modulation can be realized only by auxiliary ion implantation. In this embodiment, the relief structure 90 is etched through the surface of the light exit hole, and the dielectric region 91 and the non-dielectric region 92 that are disposed at intervals provide overall different reflectivities, so as to filter the higher-order modes, thereby forming a single-mode output.
In one embodiment, in S6, the ion implantation species and dose include:
An H+ ion with an implantation energy of 410keV and a dose of 5E+13, an H+ ion with an implantation energy of 360keV and a dose of 4E+13, an H+ ion with an implantation energy of 300keV and a dose of 3.5E+14, an H+ ion with an implantation energy of 230keV and a dose of 3.5E+14, an H+ ion with an implantation energy of 100keV and a dose of 4E+14, and an H+ ion with an implantation energy of 20keV and a dose of 4E+14.
In this embodiment, ion implantation of a particular species and dose is used to help form an electrically insulating region deep below the active region in the cavity. The electrically insulating region serves to confine the current injected into the vcsels 100 through the P-plane to a central region, which is the region where the oxide holes and the light exit holes are located. Limiting the current injected through the P-plane into the vcsels 100 to the central region, with the highest spatial overlap of the current with the LP01 fundamental mode, can reduce excitation of higher order modes.
In one embodiment, in S1, the step of forming the epitaxial wafer 110 includes:
s11, growing an N-type bragg reflector 20 on the N-type substrate 10 by using a metal organic chemical vapor deposition (MOCVD, meta l-organic IC CHEMICA L Vapor Depos it ion) or a molecular beam epitaxy (MBE, mo l ecu l ar Beam Epitaxy) method, which includes Al xGa(1-x) As material in which a high refractive index material and a low refractive index material are alternately grown. Wherein x=x 1 in the high refractive index material and 0.05< x 1 <0.2 and x=x 2 in the low refractive index material and 0.8< x 2 <0.95, each layer of Al xGa(1-x) As material has a quarter optical thickness.
And S12, forming a resonant cavity 30 on the surface of the N-type Bragg reflector 20, wherein the resonant cavity 30 comprises an Al GaAs body material with gradually changed aluminum components. The resonant cavity 30 is used to filter light of higher order modes. The resonant cavity 30 facilitates the formation of a single mode device. The active region 31 is located at a middle upper position of the resonant cavity 30. The thickness of the cavity 30 above the active region 31 is thinner and the thickness of the cavity 30 below the active region 31 is thicker.
S13, after the resonator 30 is formed to a thickness of more than 1 μm, the active region 31 is deposited, the active region 31 includes a plurality of groups of strained quantum wells containing I nGaAs and Al GaAs for generating a gain required for laser light, and the active region 31 is formed at 1/2 position in the resonator 30. After deposition of the active region 31 is completed, the remaining thickness of the cavity 30 is further grown.
And S14, forming a P-type Bragg reflector 40 (P-DBR) above the resonant cavity 30 to complete the growth of the epitaxial wafer 110. Wherein the P-type bragg mirror 40 comprises an Al yGa(1-y) As material grown alternately of a high refractive index material and a low refractive index material, wherein y=y 1 in the high refractive index material and satisfies 0.05< y 1 <0.2, y=y 2 in the low refractive index material and satisfies 0.8< y 2 <0.9, and each layer of Al yGa(1-y) As material has a quarter optical thickness.
In this embodiment, a method for manufacturing the epitaxial wafer 110 is provided, and the epitaxial wafer 110 with good properties is more conducive to the formation of the vertical cavity surface emitting laser 100 for high-speed communication.
In one embodiment, after forming the electrically insulating region 60 in S6, the step of S9 includes:
s91, fabricating the polymer material layer 80, and further depositing the dielectric layer 70 for protecting the surface and the sidewall by using the ion-enhanced chemical vapor deposition method after the polymer material layer 80 is fabricated. The layer of polymeric material 80 is located below the P-metal layer 120. The material of the polymer material layer 80 is benzocyclobutene BCB (celebrated name: benzocyc l obutene), and the molecular formula of BCB is C8H8, which is a novel active resin, and can form a thermoplastic polymer or a thermosetting polymer. The layer of polymeric material 80 has a low dielectric constant and dielectric loss, which helps to reduce the device capacitance.
S92, P surface is drilled, and front surface gold plating is performed to form a gold electrode on the P metal layer 120.
S93, etching the N step, evaporating the Ge/Au alloy material to form a front N metal layer 131, and further depositing a dielectric layer 70 for protecting the surface and the side wall by adopting an ion-enhanced chemical vapor deposition method after the front N metal layer 131 is manufactured.
And S94, thinning the surface of the substrate 10 far away from the N-type Bragg reflector 20, and further performing back alloy evaporation to form a back N-metal layer 132.
S95, wafer is split to form a plurality of vertical cavity surface emitting lasers 100 with different emergent light powers for high-speed communication. All the processes are completed so far, and the vertical cavity surface emitting laser 100 for high-speed communication as shown in fig. 1 is formed.
In a specific embodiment, a vertical facet laser for high speed communications with a shortened resonant cavity, special ion implantation, and special relief structure 90 is fabricated using the fabrication method of any of the above embodiments. The specific structure of the relief structure 90 is as follows: wherein the diameter of the oxidized pores is 7 microns. The first dielectric region 91a (central portion) of the relief structure 90 is circular with a diameter of 5 microns. The second dielectric region 91b (the peripheral first layer structure) of the relief structure 90 has an inner and outer diameter of 8 microns and 11 microns, respectively. The third dielectric region 91c (peripheral second layer structure) of the relief structure 90 has an inner and outer diameter of 13 microns and 15 microns, respectively.
Wherein the central portion of the relief structure 90, i.e., the first dielectric region 91a, provides the best reflectivity, the radius of the fundamental mode LP01 mode is about 7.5 microns, and the principal energy is centered and highly coincident with the central portion of the relief structure 90 (the first dielectric region 91 a), so that the fundamental mode LP01 mode is well excited. While the primary light intensity of the secondary higher order modes LP11/LP12/LP21 and higher order modes is distributed outside the radius of 5 μm, a large loss is generated in the low reflectivity region (the first non-dielectric region 92a and the second non-dielectric region 92 b) between the first dielectric region 91a, the second dielectric region 91b and the third dielectric region 91c, so that only the fundamental mode can obtain lasing due to attenuation in the mode competition of the laser cavity.
The specific effects are shown in fig. 3 and 5. As shown in fig. 3, the laser modulation frequency (3 dB bandwidth of the S21 parameter) is increased from the 16.2GHz bandwidth of the conventional device to 20.1GHz due to the shortened resonator, the special ion implantation and the relief structure 90 employed in the above-described embodiments of the present invention.
As shown in fig. 4 and 5, the spectrum of the device, as viewed spectrally, changes from a conventional device (shown in fig. 4) multimode to a single mode output of the device of the invention (fig. 5) due to the shortened resonator, special ion implantation and relief structure 90 employed in the above-described embodiments of the invention.
Vertical cavity surface emitting laser for high-speed communication formed in the present invention the vertical cavity surface emitting laser for high-speed communication provided in the present invention can be used for an emission light source of a high-speed optical module of 400G/800G/1.6T. Compared with the traditional short-distance data communication with a transmission distance smaller than 500 meters, the vertical cavity surface emitting laser for high-speed communication provided by the invention can be used for high-speed optical interconnection of more than 500-2000 meters.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (10)
1. A vertical cavity surface emitting laser for high speed communications, comprising:
Epitaxial wafer, epitaxial wafer includes: the device comprises a substrate, an N-type Bragg reflector, a resonant cavity, an active region formed in the resonant cavity and a P-type Bragg reflector which are sequentially arranged from bottom to top;
an oxide layer formed in the cavity over the active region;
an electric insulation region formed after ion implantation, wherein the electric insulation region is formed below the active region in the resonant cavity from top to bottom;
A dielectric layer formed on the epitaxial wafer; and
A P metal layer formed on the epitaxial wafer;
Wherein the total thickness of the resonant cavity is 1/2 times of the optical wavelength;
The vertical cavity surface emitting laser further comprises a light outlet hole, wherein the light outlet hole is formed on the P-type Bragg reflector, and the diameter of the light outlet hole is larger than that of the oxidation hole;
the light emergent hole is provided with a relief structure, the relief structure is formed by partially etching the surface of the dielectric layer, and the relief structure is provided with a non-dielectric region and a dielectric region;
The dielectric region includes: the first medium region, the second medium region and the third medium region;
The non-dielectric region includes: a first non-dielectric region and a second non-dielectric region;
The first non-medium area is arranged between the first medium area and the second medium area; the second non-medium region is arranged between the second medium region and the third medium region;
the first dielectric region is solid and round, and a straight line formed by connecting the center of the first dielectric region and the center of the oxidation hole is perpendicular to the extension plane where the substrate is positioned; the diameter of the first medium region is smaller than the diameter of the oxidation hole;
the second medium area is annular, and the center of the inner circle and the center of the outer circle of the second medium area are overlapped with the center of the first medium area; the ring width of the second medium region is the first width;
the third medium region is annular, and the center of the inner circle and the center of the outer circle of the third medium region are overlapped with the center of the first medium region; the annular width of the third medium region is a second width;
The first width is greater than the second width;
The first dielectric region has a diameter greater than the first width.
2. The vertical cavity surface emitting laser for high speed communication according to claim 1, wherein said first non-dielectric region and said second non-dielectric region are each annular;
the annular width of the first non-medium area is a third width;
the annular width of the second non-medium area is a fourth width;
the third width is greater than the fourth width.
3. The vertical cavity surface emitting laser for high speed communication according to claim 2, wherein the diameter of said oxidized aperture is 6-10 microns.
4. A vertical cavity surface emitting laser for high speed communication according to claim 3, wherein said oxidized aperture has a diameter of 7 microns and said first dielectric region has a diameter of 5 microns;
the first width is 3 microns and the second width is 2 microns.
5. The vcl for high-speed communication according to any of claims 1-4, wherein the material of the dielectric region is silicon nitride.
6. The vcsels for high-speed communication according to claim 5, wherein the electrically insulating region is formed by ion implantation from the P-bragg reflector down to the resonator, and the implantation depth of the electrically insulating region reaches below the active region, and the electrically insulating region is configured to limit the current to be injected into the vcsels through the P-plane to a central region where the oxidation hole and the light exit hole are located.
7. A method of fabricating a vertical cavity surface emitting laser for high speed communications, comprising:
S1, forming an epitaxial wafer on a wafer, wherein the epitaxial wafer comprises: the device comprises a substrate, an N-type Bragg reflector, a resonant cavity, an active region formed in the resonant cavity and a P-type Bragg reflector which are sequentially arranged from bottom to top; wherein the total thickness of the resonant cavity is 1/2 times of the optical wavelength;
S2, after the growth of the epitaxial wafer is completed, carrying out P metal layer deposition;
s3, depositing a dielectric layer by adopting a plasma enhanced chemical vapor deposition method, wherein the dielectric layer is used for protecting the P metal layer and the epitaxial wafer;
s4, forming a pit by adopting an inductively coupled plasma-reactive ion etching method, wherein the pit exposes the side wall which needs wet oxidation;
S5, forming an oxide layer by wet oxidation above the active region, wherein the oxide layer comprises an oxide hole, and the diameter of the oxide hole is D0; in the resonant cavity, an epitaxial material above the active region is an Al xGa1-x As material, wherein x=0.98-0.99,6 micrometers is less than or equal to D0 and less than or equal to 10 micrometers;
S6, performing ion implantation after adopting photoresist to protect the light-emitting area and part of the metal contact area so as to form an electric insulation area, wherein the electric insulation area is formed below the active area in the resonant cavity from top to bottom in the epitaxial wafer;
s7, depositing a dielectric layer on the side wall of the pit by adopting a plasma enhanced chemical vapor deposition method;
s8, defining a light outlet hole of the vertical cavity surface emitting laser on the dielectric layer, defining an etching pattern of a relief structure through photoetching, and further etching the dielectric layer at the light outlet hole to form the relief structure;
wherein the diameter of the light emergent hole is larger than that of the oxidation hole; the relief structure has a non-dielectric region and a dielectric region;
The dielectric region includes: the first medium region, the second medium region and the third medium region;
The non-dielectric region includes: a first non-dielectric region and a second non-dielectric region;
The first non-medium area is arranged between the first medium area and the second medium area; the second non-medium region is arranged between the second medium region and the third medium region;
the first dielectric region is solid and round, and a straight line formed by connecting the center of the first dielectric region and the center of the oxidation hole is perpendicular to the extension plane where the substrate is positioned; the diameter of the first medium region is smaller than the diameter of the oxidation hole;
the second medium area is annular, and the center of the inner circle and the center of the outer circle of the second medium area are overlapped with the center of the first medium area; the ring width of the second medium region is the first width;
the third medium region is annular, and the center of the inner circle and the center of the outer circle of the third medium region are overlapped with the center of the first medium region; the annular width of the third medium region is a second width;
The first width is greater than the second width;
The diameter of the first medium region is larger than the first width;
s9, manufacturing an N metal layer and splitting to form a plurality of vertical cavity surface emitting lasers.
8. The method for manufacturing a vertical cavity surface emitting laser for high speed communication according to claim 7, wherein in S6, the kind and the dose of the ion implantation include:
An H+ ion with an implantation energy of 410keV and a dose of 5E+13, an H+ ion with an implantation energy of 360keV and a dose of 4E+13, an H+ ion with an implantation energy of 300keV and a dose of 3.5E+14, an H+ ion with an implantation energy of 230keV and a dose of 3.5E+14, an H+ ion with an implantation energy of 100keV and a dose of 4E+14, and an H+ ion with an implantation energy of 20keV and a dose of 4E+14.
9. The method of manufacturing a vertical cavity surface emitting laser for high speed communication according to claim 7, wherein in S1, the step of forming the epitaxial wafer comprises:
S11, growing an N-type Bragg reflector on an N-type substrate by utilizing an organic metal chemical vapor deposition method or a molecular beam epitaxy method, wherein the N-type Bragg reflector comprises an Al xGa(1-x) As material which is formed by alternately growing a high-refractive-index material and a low-refractive-index material, x=x 1 in the high-refractive-index material and 0.05< x 1 <0.2 is met, x=x 2 in the low-refractive-index material and 0.8< x 2 <0.95 is met, and the thickness of each layer of Al xGa(1-x) As material is one fourth of the optical thickness;
s12, forming a resonant cavity on the surface of the N-type Bragg reflector, wherein the resonant cavity comprises an AlGaAs body material with gradually changed aluminum components;
S13, after the resonant cavity is formed to be more than 1 micrometer thick, depositing the active region, wherein the active region comprises a plurality of groups of strain quantum wells containing InGaAs and AlGaAs and is used for generating gain required by laser, and the active region is formed at 1/2 position in the resonant cavity; after the deposition of the active region is completed, further growing the residual thickness of the resonant cavity;
S14, forming a P-type Bragg reflector above the resonant cavity to complete the growth of the epitaxial wafer; wherein the P-type bragg mirror comprises an Al yGa(1-y) As material grown alternately of a high refractive index material and a low refractive index material, wherein y=y 1 in the high refractive index material and satisfies 0.05< y 1 <0.2, y=y 2 in the low refractive index material and satisfies 0.8< y 2 <0.9, and each layer of Al yGa(1-y) As material has a quarter optical thickness.
10. The method of manufacturing a vertical cavity surface emitting laser for high speed communication according to claim 7, wherein after forming said electrically insulating region in S6, the step of S9 comprises:
s91, manufacturing a polymer material layer, and further depositing a dielectric layer for protecting the surface and the side wall by adopting an ion enhanced chemical vapor deposition method after the polymer material layer is manufactured; the polymer material layer is positioned below the P metal layer;
S92, carrying out P-surface hole opening and front gold plating to form a gold electrode on the P metal layer;
s93, etching the step on the N surface, evaporating alloy materials to form a front N metal layer, and further depositing a dielectric layer for protecting the surface and the side wall by adopting an ion enhanced chemical vapor deposition method after the front N metal layer is manufactured;
s94, thinning the surface of the substrate far away from the N-type Bragg reflector, and further performing back alloy evaporation to form a back N metal layer;
s95, splitting the wafer to form a plurality of vertical cavity surface emitting lasers with different emergent light powers.
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