CN112285380A - Optical MEMS acceleration sensor and preparation method thereof - Google Patents
Optical MEMS acceleration sensor and preparation method thereof Download PDFInfo
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Abstract
本发明属于微电子机械系统的技术领域，具体涉及一种光学式MEMS加速度传感器及其制备方法。包括依次连接的光源发射层、敏感层和检测层；光源发射层的底面开设下凹槽，下凹槽的中间安装有圆形的半导体红外光源；敏感层包括方形外框和长方体形的敏感质量块，且敏感质量块通过S型支撑梁和方形外框连接；敏感质量块的中间开设有圆柱形的通孔，通孔的底部安装有第一DBR反射镜；检测层由方形的硅片为基础制成，上凹槽的槽底中间内嵌式安装有光电探测器，且上凹槽的槽底设有第二DBR反射镜；光源发射层、敏感层和检测层通过键合形成内部封闭的光学式MEMS加速度传感器。本发明的MEMS加速度传感器采用光学探测方式结合S型支撑梁的设计大大提高了测量的精度。
The invention belongs to the technical field of micro-electronic mechanical systems, and in particular relates to an optical MEMS acceleration sensor and a preparation method thereof. It includes a light source emission layer, a sensitive layer and a detection layer connected in sequence; a lower groove is set on the bottom surface of the light source emission layer, and a circular semiconductor infrared light source is installed in the middle of the lower groove; the sensitive layer includes a square outer frame and a cuboid-shaped sensitive mass The sensitive mass block is connected to the square frame through the S-shaped support beam; a cylindrical through hole is opened in the middle of the sensitive mass block, and a first DBR mirror is installed at the bottom of the through hole; the detection layer is made of a square silicon wafer. The base is made, the photodetector is embedded in the middle of the groove bottom of the upper groove, and the second DBR mirror is arranged at the groove bottom of the upper groove; the light source emission layer, the sensitive layer and the detection layer are bonded to form an internal seal optical MEMS accelerometer. The MEMS acceleration sensor of the present invention adopts the optical detection method combined with the design of the S-shaped support beam, which greatly improves the measurement accuracy.
Description
Technical Field
The invention belongs to the technical field of micro-electromechanical systems, and particularly relates to an optical MEMS acceleration sensor and a preparation method thereof.
Background
MEMS (Micro-Electro-Mechanical Systems) is an abbreviation for Micro-Electro-Mechanical Systems. In recent years, with the development of micro-machining technology and integrated optical technology, micro-opto-electro-mechanical systems (MOEMS) accelerometers, which have the significant advantages of micro-mechanical accelerometer integration, miniaturization, high precision, electromagnetic interference resistance and the like, have been widely researched at home and abroad. Currently, optical accelerometers are classified into four types according to the detection mode: fiber bragg grating accelerometers, fabry-perot interferometric accelerometers, photonic crystal nanocavity accelerometers and grating interferometric diffraction accelerometers.
The accelerometer design based on the F-P cavity utilizes the end face of the optical fiber and the hemispherical metal film to form the F-P cavity, and the metal film is plated on the movable mass block, but the requirements on the parallelism and the reflectivity of the mass block and the reflection end face of the optical fiber are high, the installation and adjustment difficulty is high, and the parallelism is difficult to ensure in the motion process of the mass block, so the application is limited; the photonic crystal nanometer cavity accelerometer is designed with a fixed beam with micropores and a mass block with micropores to form a zipper type photonic crystal nanometer cavity structure, but because a displacement structure with high acceleration-displacement sensitivity is not designed, the noise equivalent acceleration of the accelerometer is larger, and therefore an optical MEMS acceleration sensor needs to be designed.
Disclosure of Invention
Aiming at the problems in the prior art, the optical MEMS acceleration sensor and the preparation method thereof are provided, and the optical MEMS acceleration sensor with high precision and low measuring range adopts the wavelength modulation principle and has the advantages of high precision, electromagnetic interference resistance and the like. The invention is realized by the following technical scheme:
an optical MEMS acceleration sensor comprises a light source emitting layer 1, a sensitive layer 2 and a detection layer 3 which are sequentially connected; the light source emitting layer 1 is made of a square silicon wafer as a base, a lower groove is formed in the bottom surface of the light source emitting layer 1, and a round semiconductor infrared light source 11 is arranged in the middle of the lower groove;
the sensitive layer 2 is made on the basis of polysilicon, the sensitive layer 2 comprises a square outer frame 21 and a rectangular sensitive mass block 23, and the sensitive mass block 23 is connected with the square outer frame 21 through an S-shaped supporting beam 22, so that the sensitive mass block 23 is horizontally arranged in the middle of the square outer frame 21;
a cylindrical through hole is formed in the middle of the sensitive mass block 23, a first DBR reflector 24 is mounted at the bottom of the through hole, and the first DBR reflector 24 can receive direct light of the semiconductor infrared light source 11;
the detection layer 3 is made of a square silicon wafer as a base, an upper groove is formed in the top surface of the detection layer 3, a photoelectric detector 31 is embedded in the middle of the bottom of the upper groove, a second DBR (distributed Bragg Reflector) 32 is arranged at the bottom of the upper groove, and the second DBR 32 can receive refracted light of the first DBR 24;
the light source emitting layer 1, the sensitive layer 2 and the detection layer 3 form an optical MEMS acceleration sensor with an inner closed part through bonding.
Furthermore, four sides of the sensing mass 23 are respectively connected with the corresponding square outer frame 21 through the S-shaped supporting beams 22, a connection point of each S-shaped supporting beam 22 and the corresponding side of the sensing mass 21 is a geometric center point of the side, and the S-shaped supporting beams 22 on the opposite sides of the sensing mass 23 are arranged in an axisymmetric manner.
Further, the semiconductor infrared light source 11 is made of SiO2 material.
Further, the first DBR mirror 24 and the second DBR mirror 32 are each formed by an overlapping stack of SiO2 layers and TiO2 layers, with the SiO2 and TiO2 layers alternating for a total of six layers.
Further, the photodetector 31 is a CMOS photodetector based on PIN photo-sensitive elements.
Furthermore, the groove bottom of the upper groove is provided with limit posts 33 corresponding to four right angles of the sensitive mass block 23, and the height of each limit post 33 is 30-80% of the depth of the upper groove.
The invention also comprises a preparation method of the optical MEMS acceleration sensor, which specifically comprises the following operation steps: preparing tablets:
taking a double-polishing SOI silicon chip with the thickness of 700um and two single-polishing silicon chips with the thickness of 650 um;
primary photoetching:
photoetching a polished surface of the first single polished silicon wafer into a square lower groove with the depth of 10 mu m;
secondary photoetching:
etching a circular light source groove with the depth of 10 microns in the middle of the bottom of the lower groove by using a deep reactive ion etching method, and then depositing a SiO2 material in the circular groove by using a film deposition method to form a semiconductor infrared light source 11, so that the first single polished silicon wafer integrally forms a light source emitting layer 1;
and (3) carrying out third photoetching:
etching a cylindrical first mirror groove in the middle of upper silicon 4 of the double-polished SOI silicon wafer, wherein the depth is 10 mu m, and then alternately depositing SiO2 material and TiO2 material in the first mirror groove by using a thin film deposition method to form a first DBR mirror 24 with 6 layers of SiO2 layer and TiO2 layer alternately arranged;
four times of photoetching:
deep reactive ion etching is carried out in the middle of the double-polished SOI wafer corresponding to the first DBR reflector 24, and the etched cylindrical hole penetrates through the double-polished SOI wafer and reaches the first DBR reflector 24 to form an optical channel of the first DBR reflector 24; five times of photoetching:
etching and removing the upper layer silicon 4 and the lower layer silicon 6 of the preset area of the double-polished SOI silicon chip respectively to expose a square outer frame 21 and a sensitive mass block 23 positioned in the middle of the square outer frame, etching the middle layer silicon dioxide 5 of the double-polished SOI silicon chip between the square outer frame 21 and the sensitive mass block 23, and releasing four S-shaped supporting beams 22, so that two ends of each S-shaped supporting beam 22 are respectively connected with the center of the corresponding side face of the sensitive mass block 24 and the center of the corresponding side face of the square outer frame 21; thus, the sensitive layer 2 is integrally formed on the double-polished SOI silicon chip;
and (3) six times of photoetching:
etching a square upper groove with the depth of 10 microns on the polishing surface of the second single polished silicon wafer by using reactive ions, and etching four limiting columns 33 by using a mask, wherein the four limiting columns 33 respectively correspond to four right-angle positions of the sensitive mass block 23 and have the height of 5 microns;
and (4) carrying out seven times of photoetching:
etching a circular detector groove in the middle of the groove on the second single polished silicon wafer, wherein the depth of the circular detector groove is 10 microns, and preparing a CMOS photoelectric detector 31 based on a PIN photosensitive element in the first mirror groove;
deposition:
alternately depositing SiO2 material and TiO2 material at the bottom of the upper groove of the second single polished silicon wafer to form a second DBR mirror 32 with 6 layers of SiO2 layer and TiO2 layer alternately; so far, the second single polished silicon wafer integrally forms a detection layer 3; silicon-silicon bonding:
and sequentially carrying out silicon-silicon bonding on the prepared and molded light source emitting layer 1 silicon wafer, sensitive layer 2 silicon wafer and detection layer 3 silicon wafer to realize sealing and packaging, and forming an optical microcavity between the first DBR reflector 24 and the second DBR reflector 32.
The invention has the following beneficial technical effects:
the optical MEMS acceleration sensor comprises a light source emitting layer, a sensitive layer and a detection layer, wherein the light source emitting layer, the sensitive layer and the detection layer form the optical MEMS acceleration sensor with the inner part sealed through bonding, and a reflector of an F-P cavity is prepared at the bottom of a sensitive mass block, so that an optical microcavity is formed between a first DBR reflector and a second DBR reflector, the problem that the traditional optical microcavity is difficult to assemble and adjust is solved, meanwhile, a novel S-shaped supporting beam structure is designed, the high parallelism of the sensitive mass block in the movement process is ensured, and the reliability of the movement of the sensitive mass block is enhanced by adopting a limiting column structure;
in operation, infrared light emitted by the semiconductor infrared light source is directed into the first DBR mirror through the optical channel of the first DBR mirror, under the action of external acceleration load, the sensitive mass block generates vertical displacement, so that the length of a cavity body of the optical microcavity is changed, the spectral wavelength transmission peak value of the optical microcavity is changed, the wavelength variation is finally detected by the photoelectric detector to achieve the purpose of measuring the external acceleration load, the function of the acceleration and the transmission wavelength is obtained by combining the relation between the deflection degree of the S-shaped supporting beam and the system acceleration, the linearity is more than 99.99%, the structural parameters are designed and optimized through finite element simulation software, the simulation result shows that the designed optical MEMS acceleration sensor has the working frequency of 510Hz, the measurement sensitivity of 54.8nm/g and the highest resolution of 1mg, and the measurement precision is greatly improved by adopting an optical detection mode.
Drawings
Fig. 1 is a schematic structural diagram of a MEMS acceleration sensor according to the present invention.
Fig. 2 is a schematic structural diagram of a light source emitting layer according to the present invention.
FIG. 3 is a schematic view of the structure of the sensitive layer of the present invention.
FIG. 4 is a schematic structural diagram of a detection layer according to the present invention.
FIG. 5 is a schematic structural diagram of a single polished silicon wafer according to the present invention.
FIG. 6 is a schematic cross-sectional view of the primary and secondary photolithography processes of the present invention.
FIG. 7 is a schematic structural diagram of a double polished silicon wafer according to the present invention.
FIG. 8 is a schematic cross-sectional view of a triple photolithography process according to the present invention.
FIG. 9 is a cross-sectional view of a four-pass photolithography process according to the present invention.
FIG. 10 is a schematic cross-sectional view of a five-pass photolithography process of the present invention.
FIG. 11 is a schematic cross-sectional view of a six-pass photolithography process according to the present invention.
FIG. 12 is a schematic cross-sectional view of a seven-pass photolithography process according to the present invention.
FIG. 13 is a schematic cross-sectional view of a deposition process of the present invention.
FIG. 14 is a schematic cross-sectional view of a process for silicon-silicon bonding according to the present invention.
FIG. 15 is a schematic view of the working principle of the F-P chamber of the present invention.
FIG. 16 is a graph comparing the effect of the load of the present invention on the sensitive axis versus the cross axis.
Fig. 17 shows bottom plane warp of the proof mass of the present invention.
Fig. 18 is a spectral reflection diagram of the first DBR mirror and the second DBR mirror of the present invention.
Wherein the reference numbers: the detector comprises a light source emitting layer 1, a sensitive layer 2, a detection layer 3, a semiconductor infrared light source 11, a square outer frame 21, an S-shaped supporting beam 22, a sensitive mass block 23, a first DBR reflector 24, a photoelectric detector 31, a second DBR reflector 32, a limiting column 33, an upper silicon wafer 4, a middle silicon dioxide wafer 5 and a lower silicon wafer 6.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Example 1
Referring to fig. 1-4, an optical MEMS acceleration sensor includes a light source emitting layer 1, a sensitive layer 2, and a detection layer 3, which are connected in sequence;
the light source emitting layer 1 is made of a square silicon wafer as a base, a lower groove is formed in the bottom surface of the light source emitting layer 1, and a round semiconductor infrared light source 11 is arranged in the middle of the lower groove;
the sensitive layer 2 is made on the basis of polysilicon, the sensitive layer 2 comprises a square outer frame 21 and a rectangular sensitive mass block 23, and the sensitive mass block 23 is connected with the square outer frame 21 through an S-shaped supporting beam 22, so that the sensitive mass block 23 is horizontally arranged in the middle of the square outer frame 21;
a cylindrical through hole is formed in the middle of the sensitive mass block 23, a first DBR reflector 24 is mounted at the bottom of the through hole, and the first DBR reflector 24 can receive direct light of the semiconductor infrared light source 11;
The light source emitting layer 1, the sensitive layer 2 and the detection layer 3 form an optical MEMS acceleration sensor with an inner closed part through bonding.
An optical microcavity is formed between the first DBR mirror 24 and the second DBR mirror 32 of the optical MEMS acceleration sensor, and is used for modulating the wavelength of direct light, the photoelectric detector 31 is used for receiving and detecting the direct light passing through the optical microcavity, and the purpose of detecting external acceleration is achieved by detecting the wavelength variation of the direct light.
The four side surfaces of the sensing mass block 23 are respectively connected with the corresponding square outer frame 21 through the S-shaped supporting beams 22, the connecting point of each S-shaped supporting beam 22 and the corresponding side surface of the sensing mass block 21 is the geometric central point of the side surface, and the S-shaped supporting beams 22 on the opposite side surfaces of the sensing mass block 23 are arranged in an axisymmetric manner, so that the sensing mass block 23 can stably and vertically move under external acceleration load, the S-shaped supporting beams 22 have the advantages of large movement in the vertical direction and small movement in the plane direction, and the sensitive influence of the crossed axes of the accelerometer is well avoided.
The semiconductor infrared light source 11 is made of SiO2 material.
The first DBR mirror 24 and the second DBR mirror 32 are each formed by an overlapping stack of layers of SiO2 and TiO2, with the layers of SiO2 and TiO2 alternating for a total of six layers.
The photodetector 31 is a CMOS photodetector based on PIN photo-sensitive elements.
The groove bottom of the upper groove is provided with limiting columns 33 corresponding to four right angles of the sensitive mass block 23, the height of each limiting column 33 is 50% of the depth of the upper groove, and the purpose of limiting the sensitive mass block 23 to generate overlarge displacement is achieved.
Example 2
The invention also comprises a preparation method of the optical MEMS acceleration sensor, which specifically comprises the following operation steps: preparing tablets: as can be seen in figures 5 and 7,
taking a double-polishing SOI silicon chip with the thickness of 700um and two single-polishing silicon chips with the thickness of 650 um;
primary photoetching: as can be seen in figure 6 of the drawings,
photoetching a polished surface of the first single polished silicon wafer into a square lower groove with the depth of 10 mu m;
secondary photoetching: referring to fig. 6, a circular light source groove is etched in the middle of the bottom of the lower groove by a deep reactive ion etching method, the depth is 10um, then a SiO2 material is deposited in the circular groove by a film deposition method to form a semiconductor infrared light source 11, and then the first single-polished silicon wafer integrally forms a light source emitting layer 1;
and (3) carrying out third photoetching: as can be seen in figure 8 of the drawings,
a cylindrical first mirror groove is etched in the middle of upper silicon on the double-polished SOI silicon chip, the depth is 10 mu m,
then, alternately depositing SiO2 material and TiO2 material in the first mirror groove by using a thin film deposition method to form a first DBR mirror 24 with 6 layers of SiO2 layers and TiO2 layers alternately arranged;
four times of photoetching: referring to fig. 9, deep reactive ion etching is performed in the middle of the double-polished SOI wafer corresponding to the first DBR mirror 24, and the etched cylindrical hole penetrates through the double-polished SOI wafer and reaches the first DBR mirror 24, thereby forming an optical channel of the first DBR mirror 24; five times of photoetching: referring to fig. 10, an upper silicon wafer and a lower silicon wafer in a preset area of the double-polished SOI silicon wafer are respectively etched and removed, a square outer frame (21) and a sensitive mass block 23 positioned in the middle of the square outer frame are exposed, a middle silicon dioxide wafer of the double-polished SOI silicon wafer between the square outer frame 21 and the sensitive mass block 23 is etched, and four S-shaped supporting beams 22 are released, so that two ends of each S-shaped supporting beam 22 are respectively connected with the center of the corresponding side face of the sensitive mass block 24 and the center of the corresponding side face of the square outer frame 21; thus, the sensitive layer 2 is integrally formed on the double-polished SOI silicon chip;
and (3) six times of photoetching: referring to fig. 11, a square upper groove with a depth of 10um is etched on the polishing surface of the second single polished silicon wafer by using reactive ions, and four limiting columns 33 are etched by using a mask, wherein the four limiting columns 33 respectively correspond to four right-angle positions of the sensitive mass block 23 and have a height of 5 um;
and (4) carrying out seven times of photoetching: referring to fig. 12, a circular detector groove is etched in the middle of the groove on the second single-polished silicon wafer, the depth of the detector groove is 10um, and a PIN photosensitive element-based CMOS photodetector 31 is prepared in the first mirror groove;
deposition: referring to fig. 13, SiO2 material and TiO2 material are alternately deposited on the bottom of the upper groove of the second single-polished silicon wafer to form a total of 6 second DBR mirrors 32 in which SiO2 layers and TiO2 layers are alternately arranged; so far, the second single polished silicon wafer integrally forms a detection layer 3; silicon-silicon bonding: referring to fig. 14, in the bonding process, the bonding surface of the silicon wafer may be pretreated by using a plasma surface activation method to prevent damage of the sensitive structure due to high temperature.
And sequentially carrying out silicon-silicon bonding on the prepared and molded light source emitting layer 1 silicon wafer, sensitive layer 2 silicon wafer and detection layer 3 silicon wafer to realize sealing and packaging, and forming an optical microcavity between the first DBR reflector 24 and the second DBR reflector 32.
Referring to fig. 16, the working principle of the optical microcavity of the present invention, i.e., the F-P cavity, is schematically shown, the F-P cavity is composed of a first DBR mirror 24 and a second DBR mirror 32, the first DBR mirror 24 is movable, and the second DBR mirror 32 is fixed. The distance between the first DBR mirror 24 and the second DBR mirror 32 is the cavity length d, and when the first DBR mirror 24 moves, the cavity length d is changed, so that the wavelength of the transmitted light shifts, and the change amount of the cavity length can be detected by detecting the change amount of the transmission wavelength through the photodetector 31.
The invention combines the movable reflector and the movable sensitive mass block 23, and utilizes the sensitive mass block 23 to sense the external acceleration change to generate displacement, thereby causing the cavity length change, establishing the function relation of the acceleration and the transmission wavelength and achieving the purpose of measuring the external acceleration.
Fig. 17 is a graph comparing the influence of the load of the present invention on the sensitive axis and the cross axis, and the S-shaped supporting beam 22 of the present invention has very good linearity and displacement sensitivity in the sensitive axis direction, but has very small displacement in the cross axis direction, and the cross axis displacement is 2.5% of the displacement of the sensitive axis, which can be ignored, and reduces the measurement error.
Fig. 18 shows the planar warpage of the bottom of the proof mass according to the present invention, and it can be seen that in the specific implementation, the S-shaped supporting beam 22 can well control the planar warpage of the bottom of the proof mass 23 (the proof mass cannot tilt due to the translation in the vertical direction) during the displacement process, the displacement deviation of both sides is 0.2nm, the mirror offset of the center of the proof mass is 0.01nm, and the measurement error is reduced.
Therefore, the MEMS acceleration sensor adopts an optical detection mode and is combined with the design of the S-shaped supporting beam 22, the measurement precision is greatly improved, the simulation result shows that the designed optical MEMS acceleration sensor has the working frequency of 510Hz, the measurement sensitivity of 54.8nm/g and the highest resolution of 1 mg.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. An optical MEMS acceleration sensor, characterized in that: comprises a light source emitting layer (1), a sensitive layer (2) and a detection layer (3) which are connected in sequence;
the light source emitting layer (1) is made of a square silicon wafer as a base, a lower groove is formed in the bottom surface of the light source emitting layer (1), and a round semiconductor infrared light source (11) is installed in the middle of the lower groove;
the sensitive layer (2) is made on the basis of polycrystalline silicon, the sensitive layer (2) comprises a square outer frame (21) and a cuboid sensitive mass block (23), and the sensitive mass block (23) is connected with the square outer frame (21) through an S-shaped supporting beam (22), so that the sensitive mass block (23) is horizontally arranged in the middle of the square outer frame (21);
a cylindrical through hole is formed in the middle of the sensitive mass block (23), a first DBR reflector (24) is mounted at the bottom of the through hole, and the first DBR reflector (24) can receive direct light of the semiconductor infrared light source (11);
the detection layer (3) is made of a square silicon wafer as a base, an upper groove is formed in the top surface of the detection layer (3), a photoelectric detector (31) is embedded in the middle of the bottom of the upper groove, a second DBR (distributed Bragg reflector) mirror (32) is arranged at the bottom of the upper groove, and the second DBR mirror (32) can receive refracted light of the first DBR mirror (24);
the light source emitting layer (1), the sensitive layer (2) and the detection layer (3) are bonded to form an optical MEMS acceleration sensor with an inner closed part.
2. The optical MEMS acceleration sensor of claim 1, characterized in that: the four side surfaces of the sensitive mass block (23) are respectively connected with the corresponding square outer frame (21) through the S-shaped supporting beams (22), the connecting point of each S-shaped supporting beam (22) and the corresponding side surface of the sensitive mass block (21) is the geometric center point of the side surface, and the S-shaped supporting beams (22) on the opposite side surfaces of the sensitive mass block (23) are arranged in an axisymmetric mode.
3. The optical MEMS acceleration sensor of claim 1, characterized in that: the semiconductor infrared light source (11) is made of SiO2 material.
4. The optical MEMS acceleration sensor of claim 1, characterized in that: the first DBR mirror (24) and the second DBR mirror (32) are each formed by an overlapping stack of layers of SiO2 and TiO2, with six layers of SiO2 and TiO2 being alternately disposed.
5. The optical MEMS acceleration sensor of claim 1, characterized in that: the photoelectric detector (31) is a CMOS photoelectric detector based on PIN photosensitive elements.
6. The optical MEMS acceleration sensor of claim 1, characterized in that: the bottom of the upper groove is provided with limiting columns (33) corresponding to four right angles of the sensitive mass block (23), and the height of each limiting column (33) is 30-80% of the depth of the upper groove.
7. The method for manufacturing an optical MEMS acceleration sensor of any one of claims 1 to 6, wherein: the method specifically comprises the following operation steps:
preparing tablets:
taking a double-polishing SOI silicon chip with the thickness of 700um and two single-polishing silicon chips with the thickness of 650 um;
primary photoetching:
photoetching a polished surface of the first single polished silicon wafer into a square lower groove with the depth of 10 mu m;
secondary photoetching:
etching a circular light source groove with the depth of 10 microns in the middle of the bottom of the lower groove by using a deep reactive ion etching method, then depositing a SiO2 material in the circular groove by using a film deposition method to form a semiconductor infrared light source (11), and forming a light source emitting layer (1) on the first single-polished silicon wafer;
and (3) carrying out third photoetching:
a cylindrical first mirror groove is etched in the middle of the upper silicon (4) of the double-polished SOI silicon wafer, the depth is 10 mu m,
then, alternately depositing SiO2 material and TiO2 material in the first mirror groove by using a thin film deposition method to form a first DBR mirror (24) with 6 layers of SiO2 layer and TiO2 layer alternately arranged;
four times of photoetching:
deep reactive ion etching is carried out in the middle of the double-polished SOI wafer corresponding to the first DBR reflector (24), and the etched cylindrical hole penetrates through the double-polished SOI wafer and reaches the first DBR reflector (24) to form an optical channel of the first DBR reflector (24);
five times of photoetching:
respectively etching and removing the upper layer silicon (4) and the lower layer silicon (6) in the preset area of the double-polished SOI silicon chip, exposing a square outer frame (21) and a sensitive mass block (23) positioned in the middle of the square outer frame, etching the middle layer silicon dioxide (5) of the double-polished SOI silicon chip between the square outer frame (21) and the sensitive mass block (23), and releasing four S-shaped supporting beams (22), so that two ends of each S-shaped supporting beam (22) are respectively connected with the center of the corresponding side face of the sensitive mass block (24) and the center of the corresponding side face of the square outer frame (21); so that the sensitive layer (2) is integrally formed on the double-polished SOI silicon wafer;
and (3) six times of photoetching:
etching a square upper groove with the depth of 10um on the polishing surface of the second single polished silicon wafer by using reactive ions, and etching four limiting columns (33) by using a mask, wherein the four limiting columns (33) respectively correspond to four right-angle positions of the sensitive mass block (23) and have the height of 5 um;
and (4) carrying out seven times of photoetching:
etching a circular detector groove with the depth of 20um in the middle of the groove on the second single polished silicon wafer, and preparing a CMOS photoelectric detector (31) based on the PIN photosensitive element in the first mirror groove;
deposition:
alternately depositing SiO2 material and TiO2 material at the bottom of the upper groove of the second single polished silicon wafer to form a second DBR mirror (32) with 6 layers of SiO2 layer and TiO2 layer alternately; so far, the second single polished silicon wafer integrally forms a detection layer (3);
silicon-silicon bonding:
and sequentially carrying out silicon-silicon bonding on the prepared and molded silicon wafer of the light source emitting layer (1), the silicon wafer of the sensitive layer (2) and the silicon wafer of the detection layer (3) to realize sealing and packaging, and forming an optical microcavity between the first DBR reflector (24) and the second DBR reflector (32).
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