CN117060223A - Anti-reflection vertical cavity surface emitting laser - Google Patents
Anti-reflection vertical cavity surface emitting laser Download PDFInfo
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- CN117060223A CN117060223A CN202311189655.3A CN202311189655A CN117060223A CN 117060223 A CN117060223 A CN 117060223A CN 202311189655 A CN202311189655 A CN 202311189655A CN 117060223 A CN117060223 A CN 117060223A
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 38
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 38
- 239000010703 silicon Substances 0.000 claims abstract description 38
- 239000000463 material Substances 0.000 claims abstract description 12
- 238000005530 etching Methods 0.000 claims description 23
- 238000000137 annealing Methods 0.000 claims description 12
- 238000004381 surface treatment Methods 0.000 claims description 12
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- 238000000151 deposition Methods 0.000 claims description 9
- 238000004544 sputter deposition Methods 0.000 claims description 7
- 239000002131 composite material Substances 0.000 claims description 6
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 4
- 229920005591 polysilicon Polymers 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 abstract description 11
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- 239000002061 nanopillar Substances 0.000 description 4
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- 238000002161 passivation Methods 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 3
- 230000003667 anti-reflective effect Effects 0.000 description 3
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- 239000002086 nanomaterial Substances 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
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- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910003902 SiCl 4 Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
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- 229910052737 gold Inorganic materials 0.000 description 1
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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
- H01S5/02—Structural details or components not essential to laser action
- H01S5/028—Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
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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]
-
- 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
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
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Abstract
The invention discloses an anti-reflection vertical cavity surface emitting laser. The anti-reflection vertical cavity surface emitting laser is characterized in that an anti-reflection layer with the thickness being odd times of the wavelength of a quarter laser is arranged on the outer surface of a light emitting window of the laser, the anti-reflection layer is composed of a silicon-based medium layer on the lower layer and a crystalline ITO layer on the upper layer, the refractive index of the silicon-based medium layer is between that of the crystalline ITO and that of the light emitting window material, the thickness of the crystalline ITO layer is 5-15 nm, a series of nano columns/nano holes are formed in the anti-reflection layer from the upper surface downwards, the diameter of the nano columns/nano holes is 50-400 nm, and the height/depth of the nano columns/nano holes is smaller than or equal to the thickness of the anti-reflection layer and larger than or equal to one third of the thickness of the anti-reflection layer. Compared with the prior art, the anti-reflection vertical cavity surface emitting laser has excellent anti-reflection performance, simple preparation process and low realization cost.
Description
Technical Field
The present invention relates to a vertical cavity surface emitting laser, and more particularly, to an antireflection vertical cavity surface emitting laser.
Background
Unlike the conventional DFB, DBR, FB EEL (edge emitting) laser, a Vertical-cavity surface emitting laser (VCSEL) is a semiconductor laser structure in which an optical resonant cavity is formed in a direction perpendicular to a semiconductor epitaxial wafer, and an emitted laser beam is perpendicular to the surface of a substrate, and has the advantages of small size, low power consumption, high efficiency, long service life, circular light beams, two-dimensional area array integration and the like, and has wide application prospects in various fields such as optical communication, attitude sensing sensors, printing, magnetic storage and the like. Because the conventional VCSEL has the defects of thin active region, short cavity length, small single-layer gain and the like, in order to improve the effective photon limiting capability, an oxidation limiting DBR structure is adopted at present. The oxide holes formed by the oxide confinement structure have very good lateral control over the current injected into the active region, so that there is little current in the lateral direction. Meanwhile, the oxidation hole structure can also transversely restrict the light emitted by the laser active region to a certain extent, so that the laser has fewer modes, and the vertical cavity surface laser with fewer modes can be stably coupled with the optical fiber.
When the vertical cavity surface laser transmits light among the devices, the device end surface reflects part of light emitted by the laser back to the laser end surface, the reflectivity of the laser end surface reflects the light reflected by the device end surface to the laser end surface back again, and the light reflected by the laser end surface and the light emitted by the laser have phase difference and light intensity difference, and the two types of light are received by the device at the same time, so that the transmission quality of optical communication signals can be deteriorated. In addition, the light reflected back to the laser interacts with the spontaneous light of the laser, which changes the initial operating characteristics of the laser, such as broadened spectral linewidth, increased threshold current, reduced signal-to-noise ratio, and increased relative intensity noise, and affects the performance and reliability of the laser. It is therefore necessary to improve the emission resistance of the vcsels.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides an anti-reflection vertical cavity surface emitting laser with excellent anti-reflection performance, which has simple preparation process and low realization cost.
The technical scheme adopted by the invention specifically solves the technical problems as follows:
an anti-reflection vertical cavity surface emitting laser, wherein an anti-reflection layer with thickness being odd times of quarter laser wavelength is arranged on the outer surface of a light emitting window of the laser, the anti-reflection layer is composed of a silicon-based dielectric layer on the lower layer and a crystalline ITO layer on the upper layer, the refractive index of the silicon-based dielectric layer is between that of the crystalline ITO and that of the light emitting window material, the thickness of the crystalline ITO layer is 5-15 nm, a series of nano columns/nano holes are formed in the anti-reflection layer from the upper surface downwards, the diameter of each nano column/nano hole is 50-400 nm, and the height/depth of each nano column/nano hole is smaller than or equal to the thickness of the anti-reflection layer and larger than or equal to one third of the thickness of the anti-reflection layer.
Preferably, the silicon-based dielectric layer is one or more of the following materials: siON, siN x Nano polysilicon.
Preferably, the anti-reflection VCSEL is an oxidation-limited VCSEL.
Preferably, the preparation method of the anti-reflection layer comprises the following steps:
s1, forming the silicon-based dielectric layer on the outer surface of a light emergent window of a laser;
s2, carrying out hydrophobic surface treatment on the surface of the silicon-based dielectric layer;
s3, depositing amorphous ITO with the thickness of 5-15 and nm on the surface of the silicon-based dielectric layer to form an amorphous ITO film with non-integrity;
s4, annealing treatment is carried out to convert the deposited amorphous ITO into crystalline ITO, so as to obtain an incomplete crystalline ITO layer;
and S5, taking the incomplete crystalline ITO layer as a self-aligned mask plate, and etching the silicon-based dielectric layer to form the nano column/nano hole.
Further preferably, the hydrophobic surface treatment is performed using a radio frequency sputtering method.
Further preferably, the annealing temperature of the annealing treatment is 150-250 ℃ and the annealing time is 60-130 s.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
according to the invention, the anti-reflection layer with the nano column/nano hole microstructure is arranged on the outer surface of the traditional VCSEL light outlet window, so that the possibility that crosstalk is formed between light reflected back from the end surface of the laser and light emitted by the laser can be effectively eliminated, and the transmission quality of optical communication signals is improved; in addition, the possibility of interaction between the light reflected back to the laser and the spontaneous light of the laser is eliminated, and the use performance and reliability of the laser are improved; meanwhile, the microstructure has a very good scattering effect on light reflected back to the end face of the laser, and the possibility that the light reflected back to the end face of the laser is returned to the inside of the laser again to influence the service performance of the laser is eliminated.
The preparation method only needs to add the preparation process of the anti-reflection layer after the traditional VCSEL preparation process, does not need to greatly change the existing VCSEL preparation process, and can adopt the existing mature semiconductor equipment and process for preparing the anti-reflection layer, thereby realizing lower cost.
Drawings
FIG. 1 is a schematic cross-sectional view of an oxidation limited anti-reflective VCSEL according to the present invention;
FIGS. 2 to 8 are schematic cross-sectional structures of the oxidation-limited type anti-reflection VCSEL of the present invention having different forms of anti-reflection layers;
fig. 9 to 24 are schematic views showing a process for fabricating the oxidation-limited type anti-reflection VCSEL of the present invention.
The reference numerals in the figures have the following meanings:
1. a GaAs substrate; 2. a buffer layer; 3. an N-type DBR layer; 4. a quantum well active layer; 5. an oxidation limiting layer; 6. a P-type DBR layer; 7. a passivation layer; 8. a P-type metal; 9. an N-type metal; 10-1 to 10-8, and an antireflection layer.
Detailed Description
In order to improve the anti-reflection performance of the VCSEL, the invention aims to provide an anti-reflection layer with a nano column/nano hole microstructure on the outer surface of a traditional VCSEL light outlet window.
The anti-reflection vertical cavity surface emitting laser provided by the invention is characterized in that an anti-reflection layer with the thickness being odd times of the wavelength of a quarter laser is arranged on the outer surface of a light emitting window of the laser, the anti-reflection layer is composed of a lower silicon-based dielectric layer and an upper crystalline ITO layer, the refractive index of the silicon-based dielectric layer is between that of the crystalline ITO and that of the light emitting window material, the thickness of the crystalline ITO layer is 5-15 nm, a series of nano columns/nano holes are formed in the anti-reflection layer from the upper surface downwards, the diameter of the nano columns/nano holes is 50-400 nm, and the height/depth of the nano columns/nano holes is smaller than or equal to the thickness of the anti-reflection layer and is larger than or equal to one third of the thickness of the anti-reflection layer.
Preferably, the preparation method of the anti-reflection layer comprises the following steps:
s1, forming the silicon-based dielectric layer on the outer surface of a light emergent window of a laser;
s2, carrying out hydrophobic surface treatment on the surface of the silicon-based dielectric layer;
s3, depositing amorphous ITO with the thickness of 5-15 and nm on the surface of the silicon-based dielectric layer to form an amorphous ITO film with non-integrity;
s4, annealing treatment is carried out to convert the deposited amorphous ITO into crystalline ITO, so as to obtain an incomplete crystalline ITO layer;
and S5, taking the incomplete crystalline ITO layer as a self-aligned mask plate, and etching the silicon-based dielectric layer to form the nano column/nano hole.
In order to facilitate public understanding, the technical solution of the present invention will be described in detail by taking an oxidation-limited VCSEL as an example with reference to the accompanying drawings, and it should be noted that the anti-reflection structure in the anti-emission layer of the present invention is a nano-scale microstructure, which is exaggerated in the drawings of the specification for clarity of illustration.
Fig. 1 shows a cross-sectional structure of an oxidation-limited type anti-reflection VCSEL of the present embodiment, as shown in fig. 1, including: the structure of the GaAs substrate 1, the buffer layer 2, the N-type DBR layer 3, the quantum well active layer 4, the oxidation limiting layer 5, the P-type DBR layer 6, the passivation layer 7, the P-type metal 8 and the N-type metal 9 is the same as that of the conventional oxidation limiting VCSEL, wherein an oxidation hole is formed in the middle of the oxidation limiting layer, and the light emergent window of the laser is surrounded by the P-type metal 8. As shown in fig. 1, the present invention is different from the conventional VCSEL in that an anti-reflection layer 10-1 having a thickness of (2n+1) λ/4 is provided on the outer surface of the light-emitting window, where λ is the wavelength of the laser, n is a natural number, i.e., the thickness of the anti-reflection layer 10-1 is an odd multiple of one-fourth of the wavelength of the laser; the anti-reflection layer 10-1 is composed of a lower silicon-based dielectric layer and an upper crystalline ITO layer, the refractive index of the silicon-based dielectric layer is between the refractive index of the crystalline ITO (lower refractive index) and the refractive index of the light emergent window material (higher refractive index), the thickness of the crystalline ITO layer is 5-15 nm, a series of nano columns/nano holes are formed in the anti-reflection layer 10-1 from the upper surface downwards, the diameter of each nano column/nano hole is 50-400 nm, and the height/depth of each nano column/nano hole is smaller than or equal to the thickness of the anti-reflection layer and is larger than or equal to one third of the thickness of the anti-reflection layer 10-1. Fig. 1 shows a form of the nano microstructure in the anti-reflection layer 10-1, wherein the height/depth of the nano pillars/nano holes is equal to the thickness of the anti-reflection layer, the side walls of the nano pillars/nano holes are basically perpendicular to the outer surface of the light emitting window, when the etching depth and the etching process adopted in the preparation process of the anti-reflection layer are different, the anti-reflection layer can take on other different forms, 10-2 to 10-8 in fig. 2 show other forms of the anti-reflection layer respectively, the height/depth of the nano pillars/nano holes under part forms is smaller than the thickness of the anti-reflection layer, and the side walls of the nano pillars/nano holes under part forms are not perpendicular to the outer surface of the light emitting window and are in a cone shape or an inverted cone shape.
The material of the silicon-based dielectric layer needs to consider etching performance on one hand and meets the refractive index requirement on the other hand, so that one or more of the following materials are preferable: siON, siN x Nano polysilicon.
The outer surface of the laser light-emitting window is provided with a nano-structure layer with nano columns/nano holes, and when the size of the nano-structure layer is small enough, the nano-structure layer and the air layer form a composite layer with refractive index continuously changing. The refractive index of the composite layer is gradually reduced from inside to outside by taking the end face of the laser as the inside and the face opposite to the end face of the laser as the outside, and finally the refractive index of the composite layer is the same as that of air. The refractive index of the composite layer changes inversely, as seen from the outside to the inside, to become progressively larger. When the light wave emitted by the laser is larger than the diameter of the nano column/nano hole, the light wave reflected back to the end face of the laser is subjected to the continuous refractive index change effect in the composite layer, the microstructure cannot be distinguished, the reflection phenomenon caused by the rapid refractive index change is eliminated, and the possibility that the light wave reflected back to the end face of the laser is returned to the area is eliminated.
In addition, the nano column/nano hole structure has very good scattering effect on the light reflected back to the end face of the laser, and eliminates the possibility that the light reflected back to the end face of the laser influences the service performance of the laser from the new back to the inside of the laser
The preparation process of the oxidation limiting type anti-reflection VCSEL specifically comprises the following steps:
step 1, the section of the epitaxial wafer selected in the embodiment is shown in fig. 9, and the epitaxial wafer comprises a GaAs substrate, a buffer layer, an N-type DBR layer, a quantum well active layer and a P-type DBR layer from bottom to top; coating photoresist on the surface of the epitaxial wafer, wherein the thickness of the photoresist is 3-10 um; exposing and developing the photoresist to obtain P-Mesa annular photoresist, see FIG. 10;
step 2, etching the epitaxial wafer obtained in the step 1 by adopting an ICP dry etching process, wherein etching gas is Cl 2 /BCl 3 Or Cl 2 /SiCl 4 Etching to 1-10 pairs of P-DBR below the quantum well layer to form a P Mesa step structure, so that the high-alumina layer to be oxidized is exposed, see FIG. 11; removing the photoresist to obtain a P Mesa table, see FIG. 12;
step 3, oxidizing Al in the high-alumina layer to be oxidized by adopting a wet oxidation process to obtain a P Mesa step structure with an oxidation limiting structure, see FIG. 13;
step 4, depositing a passivation layer on the surface of the epitaxial wafer obtained in the step 3, wherein the coating process is PECVD or ALD, and the material of the passivation layer is SiN x 、SiON、Al 2 O 3 、TiO 2 The film layer can be a single layer or a laminated layer of the above film materials, the film thickness is 50-500 nm, and the water vapor barrier capacity WVTR is 5E -2 ~1E -4 See fig. 14;
step 5, for the epitaxy obtained in step 4Etching a metal Via hole in the dielectric layer by the wafer, wherein etching gas is CF 4 +ar or BOE, resulting in an epitaxial wafer with Via holes, see fig. 15;
step 6, filling Via holes with deposited metal of the epitaxial wafer obtained in the step 5, wherein the metal is Au, pt, ag, al, and the like, and referring to FIG. 16; the existing preparation process of the oxidation-limited VCSEL can be completed, and only an independent laser or a laser array is needed to be segmented from a wafer according to the requirement;
step 7, depositing a silicon-based dielectric layer on the epitaxial wafer obtained in the step 6, wherein the material of the silicon-based dielectric layer is preferably SiON or SiN x Nano polycrystalline Si, film thickness is the anti-reflective layer target thickness minus the crystalline ITO layer target thickness, see fig. 17;
step 8, coating photoresist on the surface of the epitaxial wafer obtained in the step 7, wherein the thickness of the photoresist is 5-15 um; exposing and developing the photoresist, only leaving the photoresist in the light-emitting window, and leaving the rest areas without the photoresist, see fig. 18;
step 9, etching the silicon-based dielectric layer on the epitaxial wafer finished in the step 8, wherein etching gas is CF 4 +Ar or BOE, photoresist is removed after etching, and a silicon-based dielectric layer is left on the surface of a light emergent window of the laser after etching is finished, see FIG. 19;
step 10, coating photoresist on the surface of the epitaxial wafer obtained in the step 9, wherein the thickness of the photoresist is 5-15 um; exposing and developing the photoresist, so that the surface of the light-emitting window is free of the photoresist, and the rest areas are covered by the photoresist, see FIG. 20;
step 11, carrying out hydrophobic surface treatment on the silicon-based dielectric layer on the epitaxial wafer light emergent window obtained in the step 10, wherein the surface contact angle of the silicon-based dielectric layer after the hydrophobic surface treatment is increased, and the specific surface contact angle can be regulated and controlled by adjusting the hydrophobic surface treatment process parameters according to actual needs; the hydrophobic surface treatment can be performed by various existing chemical or physical methods, such as radio frequency sputtering, catalytic chemical vapor deposition, etc., in this embodiment, the hydrophobic surface treatment is performed by using a radio frequency sputtering method, the sputtering target is polytetrafluoroethylene, the sputtering gas is argon, the sputtering power is 20-100W, the sputtering pressure is 5-50 Pa, and the surface treatment time is 5-60 s, see fig. 20;
step 12, transferring the epitaxial wafer subjected to the hydrophobic surface treatment to an ITO deposition chamber in a vacuum environment for amorphous ITO deposition, wherein the film thickness is 5-15 nm, and an incomplete amorphous ITO film is formed on the surface of the silicon-based dielectric layer, see FIG. 21;
the contact angle of the surface of the silicon-based dielectric layer is increased after the hydrophobic treatment, an incomplete film layer is formed by depositing ITO with proper thickness, the incompleteness is determined by the contact angle of the surface of the silicon-based dielectric layer, the ITO forms a film similar to a net structure when the contact angle is not too large (usually 100-120 DEG), as shown in a left picture in FIG. 22, at the moment, the ITO is continuous, a large number of holes are distributed in the surface of the ITO film, and the diameter of the holes is 50-100 nm; when the contact angle is large (usually more than 120 degrees), the ITO forms a completely discontinuous film, as shown in the right picture in fig. 22, a large number of ITO 'islands' are distributed in the surface of the ITO film, the ITO 'islands' are surrounded by continuous cavities, and the diameter of each ITO 'island' is 100-400 nm;
removing the photoresist after ITO deposition is completed, and obtaining an epitaxial wafer as shown in figure 23;
step 13, performing annealing treatment to convert the deposited amorphous ITO into crystalline ITO so as to improve the etching resistance stability of the ITO serving as a self-aligned mask plate, and reducing the refractive index of the annealed ITO to 1.6 so as to improve the overall anti-reflection performance of the anti-reflection layer; the annealing temperature in the embodiment is 150-250 ℃ and the annealing time is 60-130 s;
step 14, etching the silicon-based dielectric layer by taking the obtained incomplete crystalline ITO layer as a self-aligned mask plate, wherein the silicon-based dielectric layer of the ITO coverage area is protected, and the silicon-based dielectric layer of the area which is not covered by the ITO is etched; the etching gas may be CF 4 +Ar、CHF 3 +Ar、CH 2 F 2 +Ar、C 4 F 8 +Ar or CF 4 +CHF 3 +Ar、CF 4 +CH 2 F 2 +Ar、CF 4 +CF 8 +Ar CHF 3 +CH 2 F 2 +Ar、CHF 3 +CF 8 +Ar、CH 2 F 2 +CF 8 +Ar, the etching power of the embodiment is 50-300W, and the etching pressure is 0.1-5 Pa; the silicon-based dielectric layer of the area which is not covered by ITO is completely or partiallyEtching off, ending etching and removing the photoresist after reaching a preset etching depth to obtain an anti-reflection layer with a microstructure of a series of nano columns/nano holes downwards from the upper surface, as shown in fig. 24; depending on the etching depth and etching process employed, various types of anti-reflective layers as shown in FIGS. 1 to 8 may be formed.
Claims (6)
1. The anti-reflection vertical cavity surface emitting laser is characterized in that an anti-reflection layer with the thickness being odd times of the wavelength of a quarter laser is arranged on the outer surface of a light emitting window of the laser, the anti-reflection layer is composed of a lower silicon-based dielectric layer and an upper crystalline ITO layer, the refractive index of the silicon-based dielectric layer is between that of the crystalline ITO and that of the light emitting window material, the thickness of the crystalline ITO layer is 5-15 nm, a series of nano columns/nano holes facing downwards from the upper surface are formed in the anti-reflection layer, the diameter of the nano columns/nano holes is 50-400 nm, and the height/depth of the nano columns/nano holes is smaller than or equal to the thickness of the anti-reflection layer and is larger than or equal to one third of the thickness of the anti-reflection layer.
2. The antireflection VCSEL as claimed in claim 1 wherein the silicon based dielectric layer is a composite of one or more of the following materials: siON, siN x Nano polysilicon.
3. The antireflection VCSEL as defined in claim 1 wherein the VCSEL is an oxidation-confined VCSEL.
4. The antireflection vertical cavity surface emitting laser according to any one of claims 1 to 3, wherein the method for producing the antireflection layer comprises the steps of:
s1, forming the silicon-based dielectric layer on the outer surface of a light emergent window of a laser;
s2, carrying out hydrophobic surface treatment on the surface of the silicon-based dielectric layer;
s3, depositing amorphous ITO with the thickness of 5-15 and nm on the surface of the silicon-based dielectric layer to form an amorphous ITO film with non-integrity;
s4, annealing treatment is carried out to convert the deposited amorphous ITO into crystalline ITO, so as to obtain an incomplete crystalline ITO layer;
and S5, taking the incomplete crystalline ITO layer as a self-aligned mask plate, and etching the silicon-based dielectric layer to form the nano column/nano hole.
5. The antireflection vertical cavity surface emitting laser according to claim 4, wherein said hydrophobic surface treatment is performed using a radio frequency sputtering method.
6. The antireflection vertical cavity surface emitting laser according to claim 4, wherein the annealing treatment has an annealing temperature of 150 to 250 ℃ and an annealing time of 60 to 130 s.
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