阅读说明：本技术 中红外波段激光器外延结构、中红外波段微腔激光器及其制备方法和应用、检测器件 (Intermediate infrared band laser epitaxial structure, intermediate infrared band micro-cavity laser, preparation method and application thereof, and detection device ) 是由 房丹 牛守柱 方铉 杜鹏 刘晓磊 赵鸿滨 王登魁 魏志鹏 王晓华 王菲 于 2020-11-18 设计创作，主要内容包括：本发明提供了一种中红外波段激光器外延结构、中红外波段微腔激光器及其制备方法和应用、检测器件,涉及半导体器件技术领域,包括依次设置于衬底上的过滤缓冲层、n型波导层、n型限制层、有源区、p型限制层、p型波导层和p型覆盖层；过滤缓冲层包括In_xGa_(1-x)As_ySb_(1-y),其中,0<x<1,0<y<1。本发明微腔激光器外延结构由于采用四元合金缓冲层In_xGa_(1-x)As_ySb_(1-y),能够更加灵活的匹配衬底晶格常数和激光器有源区结构,从而降低因为晶格失配所产生的缺陷,使得缺陷被限制在Si和缓冲层界面,不向上继续延伸而降低有源区材料质量,更好地对器件内部光场进行调控。(The invention provides an epitaxial structure of a middle infrared band laser, a middle infrared band micro-cavity laser, a preparation method, application and a detection device thereof, relating to the technical field of semiconductor devices and comprising a filtering buffer layer, an n-type waveguide layer, an n-type limiting layer, an active region, a p-type limiting layer, a p-type waveguide layer and a p-type covering layer which are sequentially arranged on a substrate; the filter buffer layer comprises In x Ga 1‑x As y Sb 1‑y Wherein, 0<x<1，0<y<1. The epitaxial structure of the microcavity laser adopts the quaternary alloy buffer layer In x Ga 1‑x As y Sb 1‑y Can more flexibly match the substrate lattice constant with the active region structure of the laser, thereby reducing the defects caused by lattice mismatchAnd the defects are limited at the interface of the Si and the buffer layer and do not extend upwards to reduce the quality of the active area material, so that the optical field in the device can be better regulated and controlled.)

1. An epitaxial structure of a mid-infrared band laser is characterized by comprising a filtering buffer layer, an n-type waveguide layer, an n-type limiting layer, an active region, a p-type limiting layer, a p-type waveguide layer and a p-type covering layer which are sequentially arranged on a substrate;

the filtering buffer layer comprises In_xGa_1-xAs_ySb_1-yWherein, 0<x<1，0<y<1；

The substrate comprises Si;

the p-type cladding layer comprises a group III-V compound, preferably a GaSb layer.

2. The mid-infrared band laser epitaxial structure of claim 1, wherein the n-type waveguide layer, n-type confinement layer, p-type waveguide layer independently comprise AlGaAsSb or alingaas sb.

3. The mid-ir band laser epitaxial structure according to claim 1, wherein the active region comprises InGaAsSb/AlGaAsSb type I quantum wells, GaAsSb/GaAs type II quantum wells, InAs/(In) GaSb gap-broken type quantum wells, AlSb/InAs/GaInSb or InGaAsSb/AlGaInAsSb, preferably InGaAsSb/AlGaAsSb type I quantum wells.

4. The mid-ir band laser epitaxial structure according to any one of claims 1 to 3, wherein the thickness of the filter buffer layer is 0.5 to 5 μm;

preferably, the active region has a wavelength band of 1.8 to 3 microns, preferably 2 microns.

5. A method for growing an epitaxial structure of a mid-IR band laser according to any of claims 1-4, comprising the steps of:

growing a filtering buffer layer, an n-type waveguide layer, an n-type limiting layer, an active region, a p-type limiting layer, a p-type waveguide layer and a p-type covering layer on a substrate in sequence by adopting a molecular beam epitaxy method to obtain an epitaxial structure of the intermediate infrared band laser;

preferably, the epitaxial growth parameters include at least one of the following conditions:

the substrate processing temperature is 380-420 ℃;

reaction source temperature: ga is 980-;

the growth temperature is 520-600 ℃;

the III/V beam flow ratio is 5:1-12: 1.

6. A mid-infrared band microcavity laser, comprising superimposed dual-microdisk-structured microcavities having the mid-infrared band laser epitaxial structure of any one of claims 1 to 4;

preferably, each microdisk has a diameter of 4-20 microns.

7. A method for preparing the mid-infrared band micro-cavity laser as claimed in claim 6, comprising the steps of:

a) arranging a sacrificial layer on a substrate, epitaxially growing an epitaxial structure of the mid-infrared band laser, and arranging a hard mask;

b) coating an electron blocking layer on the hard mask;

c) baking and exposing the electron blocking layer according to a preset pattern so as to expose the hard mask corresponding to the preset pattern;

d) etching the exposed hard mask to expose the epitaxial structure corresponding to the preset pattern;

e) removing the residual electron barrier layer, etching the body and etching a first microdisk;

f) removing the residual hard mask, re-depositing a new hard mask, repeating the steps, etching a second microdisk around the first microdisk, and removing the residual hard mask;

g) and selectively corroding the substrate to form a micro-disk structure of the Si support to obtain the intermediate infrared band micro-cavity laser.

8. The method according to claim 7, wherein in the step a), the hard mask is disposed by plasma enhanced chemical vapor deposition;

preferably, in step c), the exposure is carried out by electron beam exposure;

preferably, in the step d), the etching adopts a reactive ion etching method;

preferably, in step e), the etching is performed by using an inductively coupled plasma method.

9. An application of the mid-infrared band micro-cavity laser of claim 6 or the mid-infrared band micro-cavity laser prepared by the preparation method of claim 7 or 8 in nonlinear optics, quantum optics, photonic integration or material detection.

10. A detection device, characterized by comprising the mid-infrared band micro-cavity laser of claim 6 or the mid-infrared band micro-cavity laser prepared by the preparation method of claim 7 or 8.

Technical Field

The invention relates to the technical field of semiconductor devices, in particular to an epitaxial structure of a middle infrared band laser, a middle infrared band micro-cavity laser, a preparation method, application and a detection device thereof.

Background

With the increasing severity of the problems of climate warming, atmospheric environmental pollution and the like, trace gas detection based on the mid-infrared band is developing vigorously. The laser spectrum gas analysis system of the Tunable Diode Laser Absorption Spectrum (TDLAS) technology is rapidly applied to various fields of environmental monitoring, early cancer medical diagnosis, toxic gas protection and the like, and has important research significance and market prospect. As the core of the detection system, the luminous wavelength, the line width, the mode and the laser device component density of the intermediate infrared laser source are the core problems of the intelligent detection system which realizes high sensitivity, multi-point monitoring, high integration and strong background gas anti-interference capability.

The semiconductor micro-cavity laser is a new type of semiconductor photoelectric device with resonant cavity with geometrical size at least close to wavelength or sub-wavelength in one dimension. The light generated during the stimulated radiation is totally reflected at the curved surface boundary of the materials with different refractive indexes, so that the light with specific wavelength circularly propagates around the boundary in the microcavity, and the amplified laser light is further realized. In the actual design process of the device, people can adjust the lasing state of the device by changing the shape of the microcavity, adjusting the materials and the structure of the cavity, improving the manufacturing process of the microcavity laser and other means. Due to the characteristics of specific geometric shape, small volume, low threshold, high integration level, good single-mode performance and the like of the semiconductor micro-cavity laser, the semiconductor micro-cavity laser can well replace the traditional semiconductor laser in many fields, realizes high-level single-mode low-threshold lasing luminescence, is an ideal gas detection light source, and has important application value in various fields such as nonlinear optics, quantum optics, photonic integration, substance detection and the like.

In order to meet the requirements of gas detection on low power consumption and high integration, the optimal method is to use a Si-based microcavity laser, however, as an indirect bandgap semiconductor, light emission of a silicon material is a typical phonon-assisted low-probability process, the light emission efficiency is low, and it is difficult to obtain a silicon-based active device, so that Si cannot be directly used as a gain medium of the microcavity device. To solve this problem, the current technical means include homoepitaxy of III-V materials and preparation of the desired morphology, followed by bonding to Si-based substrates, or Si-based heteroepitaxy using Ge materials as buffer layers, followed by final preparation of the desired morphology. However, the prior art still has a series of problems:

1. the Si-based microcavity laser is prepared by adopting a bonding process, the process steps are complex, the requirement on the processing precision of a bonding machine is high, and the difficulty in large-scale application is high.

2. The defect density in the material is increased due to lattice mismatch and the like by adopting the traditional Si-based heteroepitaxy technology with Ge or GaAs material as a buffer layer, so that the performance of the prepared Si-based microcavity laser is influenced, and for a mid-infrared device, an antimonide with a narrower energy band is required to be further adopted, so that the difference between the lattice constant of a gain medium and a substrate is further enlarged, and the strategy that GaAs/Ge is used as the buffer layer is difficult to follow.

3. The parameters which can be designed and adjusted by a single micro-cavity structure are limited, and the laser lasing mode is difficult to be flexibly and effectively adjusted and controlled by changing the parameters of the micro-disk structure.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

It is an object of the present invention to provide an intermediate infrared band laser epitaxial structure that alleviates at least one of the above problems.

The second objective of the present invention is to provide a method for growing the epitaxial structure of the mid-infrared band laser.

The invention also aims to provide a middle infrared band micro-cavity laser.

The fourth objective of the present invention is to provide a method for preparing the above mid-infrared band microcavity laser.

The fifth objective of the present invention is to provide an application of the above mid-infrared band microcavity laser.

The sixth purpose of the present invention is to provide a detection device, which comprises the above mid-infrared band micro-cavity laser.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

in a first aspect, the invention provides an epitaxial structure of a mid-infrared band laser, which comprises a filtering buffer layer, an n-type waveguide layer, an n-type limiting layer, an active region, a p-type limiting layer, a p-type waveguide layer and a p-type covering layer which are sequentially arranged on a substrate;

the filtering buffer layer comprises In_xGa_1-xAs_ySb_1-yWherein, 0<x<1，0<y<1；

The substrate comprises Si;

the p-type cladding layer comprises a group III-V compound, preferably a GaSb layer.

Further, the n-type waveguide layer, the n-type confinement layer, the p-type confinement layer and the p-type waveguide layer independently comprise AlGaAsSb or AlInGaAsSb.

Further, the active region comprises an InGaAsSb/AlGaAsSb I type quantum well, a GaAsSb/GaAs II type quantum well, an InAs/(In) GaSb gap-broken type quantum well, an AlSb/InAs/GaInSb or an InGaAsSb/AlGaInAsSb, preferably an InGaAsSb/AlGaAsSb I type quantum well.

Further, the thickness of the filtering buffer layer is 0.5-5 microns;

preferably, the active region has a wavelength band of 1.8 to 3 microns, preferably 2 microns.

In a second aspect, the present invention provides a method for growing the epitaxial structure of the mid-infrared band laser, including the following steps:

growing a filtering buffer layer, an n-type waveguide layer, an n-type limiting layer, an active region, a p-type limiting layer, a p-type waveguide layer and a p-type covering layer on a substrate in sequence by adopting a molecular beam epitaxy method to obtain an epitaxial structure of the intermediate infrared band laser;

preferably, the epitaxial growth parameters include at least one of the following conditions:

the substrate processing temperature is 380-420 ℃;

reaction source temperature: ga is 980-1080 ℃, In 750-850 ℃, As 360-400 ℃, Sb480-540 ℃ and Al 1100-1150 ℃;

the growth temperature is 520-600 ℃;

the III/V beam flow ratio is 5:1-12: 1.

In a third aspect, a mid-infrared band microcavity laser is provided, where the mid-infrared band microcavity laser includes superposed dual-microdisk-structured microcavities, and the microcavities have the epitaxial structure of the mid-infrared band laser;

preferably, each microdisk has a diameter of 4-20 microns.

In a fourth aspect, a method for preparing the above mid-infrared band microcavity laser is provided, which includes the following steps:

a) arranging a sacrificial layer on a substrate, epitaxially growing the intermediate infrared band laser epitaxial structure, and arranging a hard mask;

b) coating an electron blocking layer on the hard mask;

c) baking and exposing the electron blocking layer according to a preset pattern so as to expose the hard mask corresponding to the preset pattern;

d) etching the exposed hard mask to expose the epitaxial structure corresponding to the preset pattern;

e) removing the residual electron barrier layer, etching the body and etching a first microdisk;

f) removing the residual hard mask, re-depositing a new hard mask, repeating the steps, etching a second microdisk around the first microdisk, and removing the residual hard mask;

g) and selectively corroding the substrate to form a micro-disk structure of the Si support to obtain the intermediate infrared band micro-cavity laser.

Further, in the step a), a hard mask is arranged by adopting a plasma enhanced chemical vapor deposition method;

preferably, in step c), the exposure is carried out by electron beam exposure;

preferably, in the step d), the etching adopts a reactive ion etching method;

preferably, in step e), the etching is performed by using an inductively coupled plasma method.

In a fifth aspect, an application of the mid-infrared band micro-cavity laser or the mid-infrared band micro-cavity laser prepared by the preparation method in nonlinear optics, quantum optics, photonic integration or material detection is provided.

In a sixth aspect, a detection device is provided, which includes the mid-infrared band micro-cavity laser or the mid-infrared band micro-cavity laser prepared by the preparation method.

The epitaxial structure of the intermediate infrared band laser, the intermediate infrared band micro-cavity laser, the preparation method and the application thereof, and the detection device provided by the invention at least have the following beneficial effects:

the epitaxial structure of the microcavity laser adopts the quaternary alloy buffer layer In_xGa_1-xAs_ySb_1-yCompared with a unitary or binary material such as Ge or GaAs, the lattice constant of the substrate and the structure of the active region of the laser can be matched more flexibly, so that defects generated due to lattice mismatch are reduced, the defects are limited at the interface of Si and the buffer layer, and the quality of the material of the active region is reduced without extending upwards. The four-element material system can adjust the refractive index of the buffer layer under the condition of meeting the lattice constant of the material (substrate lattice)The constant is fixed, the ternary alloy only has fixed components and can meet the lattice constant of the substrate, the quaternary alloy can realize the lattice constant matching through the V group component in each different III group proportion, and the different components have different refractive indexes although the lattice constants are matched, so that the required refractive index can be selected under the condition of realizing the lattice constant matching), and the optical field in the device can be better regulated and controlled.

The microcavity laser of the invention introduces a cavity structure of a stacked cavity, utilizes vernier caliper effect (for a single-cavity structure, each specific structure has a series of modes with fixed mode intervals, and when two single cavities are stacked and coupled with each other, gain can be realized only by conforming to a certain mode(s) of the two cavities at the same time), namely, mode resonance between different microcavities is adopted, resonance frequency supported by both sides is selected to realize lasing, and the purpose of controlling laser mode and line width is achieved. Meanwhile, as one micro-disk structure is additionally introduced, the performance of a micro-disk device can be accurately regulated and controlled by adjusting the parameters such as the position, the size, the shape, the material and the like of the upper micro-disk, so that the performance of the device is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic view of an epitaxial structure of a mid-infrared band laser provided by the present invention;

FIG. 2 is a schematic structural diagram of a silicon-based cavity-stacked microdisk laser provided by the present invention;

FIG. 3 is a flow chart of a method for manufacturing a middle infrared band microcavity laser according to the present invention;

FIG. 4 is a diagram showing the optical field distribution of the higher order mode in the microdisk structure with a diameter of 3 μm and the single-mode output control of the dual microdisk;

fig. 5 is a schematic view of an antimonide type I quantum well laser epitaxial structure on a silicon substrate of example 1.

Icon: 1-a substrate; 2-filtering the buffer layer; a 3-n type waveguide layer; a 4-n type confinement layer; 5-an active region; a 6-p type confinement layer; a 7-p type waveguide layer; an 8-p type cladding layer.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

For silicon-based semiconductor optoelectronic integration, the lattice mismatch of silicon and buffer layer antimonide materials (e.g., GaSb) can reach 12%. The lattice mismatch between the substrate and the epitaxial layer causes poor material quality and more active region defects, thereby causing non-radiative recombination and limiting the improvement of the performance of the laser device.

Aiming at the problem of incompatibility of systems such as silicon and antimonide single-layer materials, alloys, complex quantum wells and the like, a layer-by-layer dislocation filtering buffer layer material system (In) with variable lattice constant is designed_xGa_1-xAs_ySb_1-y)。

According to a first aspect of the present invention, there is provided a mid-infrared band laser epitaxial structure, as shown in fig. 1, comprising a filtering buffer layer 2, an n-type waveguide layer 3, an n-type confinement layer 4, an active region 5, a p-type confinement layer 6, a p-type waveguide layer 7 and a p-type cladding layer 8, which are sequentially disposed on a substrate 1; the filter buffer layer 2 includes In_xGa_1-xAs_ySb_1-yWherein, 0<x<1，0<y<1; the substrate 1 includes Si; the cover layer 8 comprises a group III-V compound, preferably a GaSb layer.

The substrate 1 is a substrate with or without a tilt angle, including but not limited to Si. If the substrate is a substrate having a tilt angle θ, tan θ is 1 atomic height (substrate normal)/step length. The inclination angle may be 0 to 10 degrees (excluding 0 degree), preferably 0 to 5 degrees (excluding 0 degree), for example, 0.5 degrees, 1 degree, 2 degrees, 3 degrees, 4 degrees.

The filter buffer layer 2 includes In_xGa_1-xAs_ySb_1-yWherein, 0<x<1，0<y<1。

The buffer layer is an epitaxial basic structure, and the filtering buffer layer is a structure which reflects the layer and filters out defects generated by mismatch between the substrate and the epitaxial structure.

In_xGa_1-xAs_ySb_1-yWherein x and y are each independently any value between 0 and 1 (excluding 0 and 1). For example, x may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9 and y may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.63, 0.7, 0.8 or 0.9. Including but not limited to In_0.8Ga_0.2As_0.73Sb_0.26、In_0.65Ga_0.35As_0.65Sb_0.35、In_0.5Ga_0.5As_0.5Sb_0.5。

By introducing In of variable lattice constant_xGa_1-xAs_ySb_1-yThe dislocation filters the buffer layer by layer, and this buffer layer interface both sides can match substrate and overburden respectively on the one hand, and this alloy monomolecular layer can be controlled the defect on the monomolecular layer on the other hand, restraines the defect vertical propagation.

The variable lattice constant means that the components of the buffer layer are changed layer by layer in the growth process, so that the two sides of the interface of the buffer layer can be respectively matched with silicon and GaSb.

Layer-by-layer dislocation means that alloy monomolecular layers with different components grow layer by layer to release strain layer by layer, so that the generation of defects caused by large strain is delayed, and meanwhile, the strain can be released by adopting means such as interface regulation and the like in the monomolecular layers, so that the vertical propagation of the defects is inhibited.

Preferably, In_xGa_1-xAs_ySb_1-yIs 0.5-5 microns, e.g. 1, 2, 3, 4, 5 microns.

The n-type waveguide layer 3, the n-type confinement layer 4, the p-type confinement layer 6 and the p-type waveguide layer 7 can be made of conventional materials matched with the substrate, such as AlGaAsSb, AlInGaAsSb and the like.

The active region 5 is a region on the silicon wafer where active devices are formed, i.e., an active region quantum well.

The active region may be made of any material that can be used as an active region, including but not limited to InGaAsSb/AlGaAsSb type I quantum well, GaAsSb/GaAs type II quantum well, InAs/(In) GaSb gap-broken type quantum well, etc.

It should be noted that, for the active region structure, besides InGaAsSb/AlGaAsSb in the scheme, infrared active region structures such as AlSb/InAs/GaInSb and InGaAsSb/AlGaInAsSb may be used according to the wavelength. Here, "/" indicates the meaning of "and indicates a potential well material and a barrier material, respectively.

Preferably, the active region is an InGaAsSb/AlGaAsSb I type quantum well, and high-quality InGaAsSb/AlGaAsSb laser material with high light emitting performance can be obtained.

Preferably, the active region has a wavelength band of 1.8-3 microns, e.g., 2, 3 microns.

The active region and the waveguide structure are optimized through design, and the output requirement of the mid-infrared laser is met.

The capping layer 8 includes a group III-V compound, which is a compound formed of B, Al, Ga, In of group III and N, P, As, Sb of group V In the periodic table. Including group III-V binary compounds (GaN, GaP, GaAs, InP, GaSb, InSb, InAs, AlSb), group III-V ternary compounds (InAsSb, InGaAs), or group III-V quaternary compounds (In)_xGa_{1- x}As_ySb_1-y)。

The capping layer 8 is preferably a GaSb layer.

The invention filters the buffer layer In by growing the layer-by-layer dislocation with variable lattice constant on the substrate_xGa_1-xAs_ySb_1-yThe method realizes the gradual change of the crystal lattice from the substrate (such as silicon) to the GaSb and other materials, controls the crystal lattice defect in the monomolecular layer plane in a distributed epitaxial mode, simultaneously achieves the aims of matching the crystal lattice of the substrate and the epitaxial layer materials and inhibiting the vertical propagation of the defect, is an effective mode for realizing the heterogeneous compatibility of the substrate and the epitaxial layer materials, and prepares the epitaxial material of the microcavity laser.

In on a substrate (e.g. Si-based)_xGa_1-xAs_ySb_1-yThe quaternary alloy is used as a gradual buffer layer to realize the direct growth of the 2-micron wave band active region on the Si substrate.

According to a second aspect of the present invention, there is provided a method for growing the epitaxial structure of the mid-infrared band laser, including the following steps:

and sequentially growing a filtering buffer layer, an n-type waveguide layer, an n-type limiting layer, an active region, a p-type limiting layer, a p-type waveguide layer and a p-type covering layer on the substrate by adopting a molecular beam epitaxy method to obtain the epitaxial structure of the intermediate infrared band laser.

The method has strong operability and stable process.

In a preferred embodiment, the epitaxial growth parameters include at least one of the following conditions:

the substrate processing temperature is 380-420 ℃, such as 380, 390, 400, 410, 420 ℃;

reaction source temperature: ga is 980-1080 ℃, In 750-850 ℃, As 360-400 ℃, Sb480-540 ℃ and Al 1100-1150 ℃;

the growth temperature is 520 ℃ and 600 ℃, such as 520 ℃, 530, 540, 550, 560, 570, 580, 590 and 600 ℃;

the III/V beam flow ratio is from 5:1 to 12:1, for example 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12: 1.

Optimizing the conditions of substrate processing temperature, reaction source temperature, growth temperature, III/V family beam current ratio and the like, and realizing the film doping and alloying control and the growth rate control by adjusting the reaction source temperature and the beam current ratio to obtain high-quality epitaxial growth conditions.

On the other hand, in order to further overcome the limitation of the conventional microcavity structure and improve the microcavity effect of the antimonide gain medium, the microcavity structure is further improved so as to meet the expected performance requirement of the microcavity laser.

According to a third aspect of the present invention, there is provided a mid-infrared band microcavity laser, as shown in fig. 2, including superposed dual-microdisk-structured microcavities, where the microcavities have the above-mentioned mid-infrared band laser epitaxial structure;

the overlapped double-micro-disk structure means that two micro-disks are arranged in an up-and-down overlapped mode.

The microcavity structure can also be in the shape of a microdisc (microdisk), microcolumn, microring, or the like.

The total thickness of the two microdisks is the thickness of the entire epitaxial structure, i.e. A_thickness+B_thickness＝Epi_thicknessAnd the diameter of the micro-disk is 4-20 μm, and the specific diameter needs to be determined by calculating the quality factor of the micro-cavity according to the specific wavelength of the device.

The invention adopts a cavity-overlapping structure, and selectively regulates and controls the mode in the cavity by the vernier caliper effect, thereby realizing the regulation and control from a single mode to multiple modes of a medium-wave infrared structure. By adjusting the size, the material, the coupling strength and the like of the double-cavity structure, the mode of the gain cavity can be flexibly and efficiently selected, and the free control from a single mode to multiple modes is realized. For a single-cavity micro-cavity laser, parameters such as the size, the material and the roughness of a micro-disc directly influence parameters such as a lasing wavelength, loss and a lasing mode, and a dual-cavity structure is formed by coupling two cavities, and the lasing characteristic of the dual-cavity structure is a result of the combined action of the two cavities, so that the change of any cavity influences the lasing characteristic, more dimensions are brought to the regulation and control of the mode, and the lasing characteristic can be adjusted more flexibly.

According to a fourth aspect of the present invention, there is provided a method for manufacturing the above mid-infrared band micro-cavity laser, as shown in fig. 3, including the following steps:

a) arranging a sacrificial layer on a substrate, epitaxially growing an epitaxial structure of the mid-infrared band laser, and arranging a hard mask;

hard masks include, but are not limited to, SiO₂And (4) hard masking.

Preferably, the hard mask is arranged by adopting a plasma enhanced chemical vapor deposition method; plasma Enhanced Chemical vapor deposition (pecvd) is a method in which a gas containing atoms constituting a thin film is locally formed into a plasma by means of microwave or radio frequency, and the plasma has a strong Chemical activity and is easily reacted to deposit a desired thin film on a substrate. Can be at 250 ℃ and oxygen ion andgenerating 450nm SiO under the condition of silicon ions₂And (4) hard masking.

b) Coating an electron blocking layer on the hard mask;

c) baking and exposing the electron blocking layer according to a preset pattern so as to expose the hard mask corresponding to the preset pattern;

preferably, the exposure is carried out by electron beam exposure;

d) etching the exposed hard mask to expose the epitaxial structure corresponding to the preset pattern;

preferably, the etching adopts a reactive ion etching method;

reactive Ion Etching (RIE), which is called reactive ion etching (reactive ion etching), is a microelectronic dry etching process, and is a dry etching process, and the etching principle is that when a high-frequency voltage (RF) of 10 to 100MHZ is applied between flat electrodes, an ion layer (ion layer) with a thickness of several hundred micrometers is generated, a sample is put in the ion layer, and the ion impacts the sample at a high speed to complete chemical reaction etching, namely RIE (reactive ion etching).

e) Removing the residual electron barrier layer, etching the body and etching a first microdisk;

preferably, the etching is performed by an inductively coupled plasma method (ICP, which is a plasma source that generates a current as an energy source by electromagnetic induction with a time-varying magnetic field).

f) Removing the residual hard mask, re-depositing a new hard mask, repeating the steps, etching a second microdisk around the first microdisk, and removing the residual hard mask;

g) and selectively corroding the substrate to form a micro-disk structure of the Si support to obtain the intermediate infrared band micro-cavity laser.

Preferably, a preparation method of a typical mid-infrared band microcavity laser double-microdisk structure microcavity specifically comprises the following steps:

1. deposition of a 450nm thick layer of SiO by PECVD₂A mask layer;

2. applying L300 photoresist on SiO₂Spin-coating a layer of photoresist on the surface, and placing the photoresist onDrying the surface of a hot plate at 110 ℃ for 60s, and then carrying out primary exposure;

3. washing off unexposed parts, leaving a mask layer with patterns, and hardening the surface of a hot plate at 120 ℃ for 5 minutes;

4. SiO by RIE₂Carrying out dry etching, and generating a required pattern under the protection of the mask layer;

5. etching the body by adopting ICP to obtain the thickness of a first microdisk;

6. washing off residual SiO with hydrofluoric acid₂And a new layer of SiO is redeposited₂；

7. Repeating the above process, etching the periphery of the first micro-disk to form the shape of the second micro-disk, and cleaning the residual SiO with hydrofluoric acid₂；

8. And selectively corroding the substrate by using hydrofluoric acid and nitric acid aqueous solution corrosion with selectivity of 1:1:1 to form a micro-disk structure of the Si support, thereby realizing the preparation of the micro-cavity structure.

Preferably, Cl₂/BCl₃/N₂Volume ratio: 21: 5: 50, ICP power 200W, and RF power 120W.

The invention has simple process and is easy for industrial application.

Preferably, a layer of SiO is grown by plasma enhanced chemical vapor deposition₂And (4) hard masking, and making a pattern on the laser epitaxial wafer by adopting electron beam exposure. On the basis, an inductively coupled plasma device is adopted to prepare the microdisk structure.

In addition, according to the characteristic that antimonide materials are easy to oxidize, a technical means of combining a dry method with a wet method (forming a Si support column by carrying out wet selective etching through hydrofluoric acid and nitric acid aqueous solution) is adopted, and the concentration and time of the wet method are controlled, so that a base structure with controllable diameter and height can be obtained, a certain modification effect is realized on the smoothness degree of the side wall of the microcavity disc, and the high-quality antimonide micro-disc structure can be obtained.

According to a fifth aspect of the present invention, there is provided an application of the mid-infrared band micro-cavity laser or the mid-infrared band micro-cavity laser prepared by the above preparation method in nonlinear optics, quantum optics, photonic integration or material detection.

The mid-infrared band microcavity laser has the advantages, so that the mid-infrared band microcavity laser can be applied to the fields of nonlinear optics, quantum optics, photon integration or substance detection and the like, and has a wide application prospect.

According to a sixth aspect of the present invention, there is provided a detection device, comprising the mid-infrared band micro-cavity laser or the mid-infrared band micro-cavity laser prepared by the preparation method.

The detection device has the same advantages as the middle infrared band micro-cavity laser, and the description is omitted.

The invention is further illustrated by the following examples. The materials in the examples are prepared according to known methods or are directly commercially available, unless otherwise specified.

Example 1

An antimonide I-type quantum well laser epitaxial structure on a silicon substrate is shown in fig. 5, and sequentially comprises from bottom to top: si substrate, In_xGa_1-xAs_ySb_1-yFilter layer, n-Al_0.6Ga_0.4As_0.04Sb_0.96Waveguide layer, n-Al_0.35Ga_0.65As_0.02Sb_0.98Confinement layer, 3 XIn_0.18Ga_0.82As_0.02Sb_0.98/Al_0.25Ga_0.75As_0.02Sb_0.98Active region, p-Al_0.35Ga_0.65As_0.02Sb_0.98Confinement layer, p-Al_0.6Ga_0.4As_0.04Sb_0.96A waveguide layer and a p-GaSb cap layer.

In_xGa_1-xAs_ySb_1-yThe filter layer is In_0.8Ga_0.2As_0.73Sb_0.26And a thickness of 2 microns.

The growth method comprises the following steps:

in is grown on Si substrate In sequence by molecular beam epitaxy method_0.8Ga_0.2As_0.73Sb_0.26、n-Al_0.6Ga_0.4As_0.04Sb_0.96Waveguide layer, n-Al_0.35Ga_0.65As_0.02Sb_0.98Confinement layer, 3 XIn_0.18Ga_0.82As_0.02Sb_0.98/Al_0.25Ga_0.75As_0.02Sb_0.98Active region, p-Al_0.35Ga_0.65As_0.02Sb_0.98Confinement layer, p-Al_0.6Ga_0.4As_0.04Sb_0.96The waveguide layer and the p-GaSb cover layer are used for obtaining an epitaxial structure of the intermediate infrared band laser;

the epitaxial growth parameters include: the substrate processing temperature is 400 ℃;

reaction source temperature: ga is 1000 ℃, In 800 ℃, As 380 ℃, Sb is 500 ℃ and Al is 1100 ℃;

the growth temperature is 550 ℃;

the III/V beam flow ratio was 10: 1.

Example 2

In is different from example 1_xGa_1-xAs_ySb_1-yThe filter layer is In_0.65Ga_0.35As_0.65Sb_0.35。

Example 3

In is different from example 1_xGa_1-xAs_ySb_1-yThe filter layer is In_0.5Ga_0.5As_0.5Sb_0.5。

Example 4

The method for preparing the mid-infrared band microcavity laser with the microcavity structure by using the epitaxial structure in the embodiment 1 comprises the following steps:

1. deposition of a 450nm thick layer of SiO by PECVD₂A mask layer;

2. applying L300 photoresist on SiO₂Spin-coating a layer of photoresist on the surface, then placing the photoresist on the surface of a hot plate at 110 ℃ for drying for 60s, and carrying out first exposure after the drying is finished;

3. washing off unexposed parts, leaving a mask layer with patterns, and hardening the surface of a hot plate at 120 ℃ for 5 minutes;

4. SiO by RIE₂Dry etching is carried out, and the required pattern appears under the protection of the mask layerShaping;

5. etching the body by adopting ICP to obtain the thickness of a first microdisk;

6. washing off residual SiO with hydrofluoric acid₂And a new layer of SiO is redeposited₂；

7. Repeating the above process, etching the periphery of the first micro-disk to form the shape of the second micro-disk, and cleaning the residual SiO with hydrofluoric acid₂；

8. And selectively corroding the substrate by using hydrofluoric acid and nitric acid aqueous solution corrosion with selectivity of 1:1:1 to form a micro-disk structure of the Si support, thereby realizing the preparation of the micro-cavity structure.

Wherein, Cl₂/BCl₃/N₂Volume ratio: 21: 5: 50, ICP power 200W, and RF power 120W.

Fig. 2 is a block diagram of a typical silicon-based cavity-stacked microdisk laser including the above-described microcavity structure. The dark grey part is the Si substrate and the upper part is the quaternary buffer layer used. The pin-shaped three-dimensional structure is a gain medium. Air and other low-refractive-index media surround the disc-shaped semiconductor gain medium of the stacked cavity, and laser output is generated when the external pump is received. The lasing wavelength can be controlled by adjusting the disk-shaped energy band structures, and the lasing mode can be controlled by adjusting the sizes, materials and coupling parts of the two disk-shaped structures.

The invention establishes a mode distribution rule corresponding to the sizes of the cavities of the double microdisk, realizes the frequency enhancement of a common mode and realizes the mode screening in a mode of offsetting the modes in the microdisk with large and small sizes, as shown in figure 4.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.