WO2018014438A1 - 红外探测器像元结构及其制备方法 - Google Patents

红外探测器像元结构及其制备方法 Download PDF

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Publication number
WO2018014438A1
WO2018014438A1 PCT/CN2016/098380 CN2016098380W WO2018014438A1 WO 2018014438 A1 WO2018014438 A1 WO 2018014438A1 CN 2016098380 W CN2016098380 W CN 2016098380W WO 2018014438 A1 WO2018014438 A1 WO 2018014438A1
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Prior art keywords
infrared
layer
cavity
comb
substrate
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PCT/CN2016/098380
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English (en)
French (fr)
Inventor
康晓旭
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上海集成电路研发中心有限公司
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Priority claimed from CN201610564866.4A external-priority patent/CN106124059B/zh
Priority claimed from CN201610564510.0A external-priority patent/CN106248222B/zh
Application filed by 上海集成电路研发中心有限公司 filed Critical 上海集成电路研发中心有限公司
Priority to US16/311,060 priority Critical patent/US10816406B2/en
Publication of WO2018014438A1 publication Critical patent/WO2018014438A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/38—Radiation pyrometry, e.g. infrared or optical thermometry using extension or expansion of solids or fluids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/02—Constructional details
    • G01J5/08—Optical arrangements
    • G01J5/0853—Optical arrangements having infrared absorbers other than the usual absorber layers deposited on infrared detectors like bolometers, wherein the heat propagation between the absorber and the detecting element occurs within a solid
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/06—Forming electrodes or interconnections, e.g. leads or terminals
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
    • H10N30/072—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by laminating or bonding of piezoelectric or electrostrictive bodies
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
    • H10N30/302—Sensors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/875—Further connection or lead arrangements, e.g. flexible wiring boards, terminal pins

Definitions

  • the present invention relates to the field of semiconductor technology, and in particular, to an infrared detector pixel structure and a method for fabricating the same.
  • the infrared detector is a device that converts the incident infrared radiation signal into an electrical signal output, and uses the thermal element to detect the presence or movement of the object, and the infrared radiation outside the detector mobile phone is concentrated on the infrared sensor, and the infrared sensor uses the thermal element.
  • the thermal element outputs a signal when it receives a change in the temperature of the infrared radiation, converts it into an electrical signal, and then performs waveform analysis on the electrical signal.
  • only one type of thermistor is used, which is usually a negative temperature coefficient of amorphous silicon or vanadium oxide, and the signal of the change thereof is amplified and output through a circuit.
  • thermosensitive element the sensitivity of the detector structure using the thermosensitive element is generally not very high, and the structure is complicated, and the detection process is complicated. If a heat sensitive element with higher sensitivity is used, the material is expensive.
  • the present invention is directed to an infrared detector pixel structure and a method of fabricating the same.
  • the present invention is directed to an infrared detector pixel structure and a method of fabricating the same.
  • an external detector pixel structure of the present invention includes a bonded substrate, a silicon substrate bonded to the bonded substrate, and a piezoelectric conversion structure on the silicon substrate;
  • the bonded substrate has an infrared absorbing layer; the infrared absorbing layer is for absorbing infrared light;
  • the silicon substrate includes a sealed cavity region filled with an infrared sensitive gas
  • the piezoelectric conversion structure is located above the closed cavity region of the silicon substrate; wherein
  • the infrared light When the infrared light is selectively transmitted through the infrared window layer, a part of the infrared light is absorbed by the infrared absorption layer, and a part of the infrared light passes through the infrared absorption layer into the closed cavity, and is absorbed by the infrared sensitive gas in the sealed cavity, and the closed cavity is closed.
  • the infrared sensitive gas inside absorbs infrared light and generates heat, and the infrared absorption layer absorbs infrared light to generate heat to be transmitted to the infrared sensitive gas, so that the infrared sensitive gas is expanded and acts on the piezoelectric conversion structure, and the piezoelectric conversion
  • the piezoelectric signal formed by the structure changes to realize the detection of infrared light.
  • the piezoelectric conversion structure includes: a bottom electrode, a top electrode, and a piezoelectric material layer between the top electrode and the bottom electrode; a bottom electrode is bonded to the silicon substrate and the oxide layer; a bottom electrode is in direct contact with the closed cavity; when the infrared sensitive gas is expanded and acts on the piezoelectric conversion structure, causing a change in a piezoelectric signal formed by the piezoelectric material layer, through the top electrode and the bottom The electrodes transmit a varying piezoelectric signal to an external circuit.
  • the closed cavity region of the silicon substrate has an upper comb-like structure and a lower comb-tooth structure, and a top portion of the upper comb-tooth structure is in contact with the bottom electrode, the bottom electrode a plurality of contact blocks are connected below, and a bottom of the plurality of contact blocks is in contact with the top of the upper comb-shaped structure; the comb teeth of the upper comb-shaped structure and the comb teeth of the lower comb-shaped structure are disposed between the two; On a gap between the bottom of the comb-shaped structure and the infrared absorbing layer; a bottom of the cavity between the comb teeth of the lower comb-tooth structure is in contact with the infrared absorbing layer; the upper comb-shaped structure And a cavity between the lower comb-like structure is sealed by the bottom electrode, the oxide layer, the silicon substrate outside the sealed cavity, and the bonding substrate, thereby forming a Said closed cavity area.
  • the bonding substrate further has an interconnection circuit, and the comb teeth of the adjacent upper comb-shaped structure and the comb teeth of the lower comb-shaped structure and the infrared sensitive gas therebetween constitute a vertical a straight capacitor structure, wherein comb teeth of the lower comb-tooth structure are electrically connected to the interconnect circuit to form a lower electrode of the vertical capacitor structure, and a bottom electrode of the piezoelectric conversion structure serves as the vertical capacitor
  • the upper electrode of the structure when the infrared sensitive gas is expanded, the pressure of the infrared sensitive gas acts on the piezoelectric conversion structure and the vertical capacitance structure, causing a change in the capacitance signal of the vertical capacitance structure and causing the a piezoelectric signal of the piezoelectric material layer is changed, and the piezoelectric signal that generates the change is transmitted to the external circuit through the top electrode and the bottom electrode, and the capacitance signal is generated by the interconnection circuit and the bottom electrode It is transmitted to an external circuit to detect inf
  • the infrared window layer has a plurality of grooves located below the comb teeth adjacent to the lower comb-tooth structure and the silicon substrate outside the sealed cavity Below, and not below the comb teeth of the lower comb-like structure; the infrared absorbing layer is filled with the plurality of grooves.
  • the top of the piezoelectric conversion structure further has a dielectric protective layer covering the entire piezoelectric conversion structure.
  • an edge layer surface of the silicon substrate outside the sealed cavity region has an oxide layer; in the piezoelectric conversion structure, the piezoelectric material layer corresponds to the upper comb-tooth structure And an edge region of the piezoelectric material layer is not located in a corresponding region above the oxide layer, an edge region of the bottom electrode covers the oxide layer, and a length of the top electrode is smaller than a length of the piezoelectric material layer Thereby, the dielectric protective layer covering the entire piezoelectric conversion structure forms a multi-stepped structure.
  • the bonding substrate further has an infrared window layer at the bottom of the infrared absorbing layer for selecting a transmitted infrared light band.
  • the piezoelectric conversion structure includes a first MOS device having a first conductivity type channel and a second MOS device having a second conductivity type channel surrounding a periphery of the first MOS device;
  • the second conductivity type is opposite;
  • the first conductivity type channel corresponds to the upper intermediate region of the closed cavity, and the second conductivity type channel spans over a portion of the interlayer dielectric above the closed cavity sidewall and surrounds
  • the first conductivity type channel is disposed.
  • the present invention provides a method of fabricating the above-described infrared detector pixel structure, which comprises:
  • Step 01 providing a bonded substrate, forming the infrared absorbing layer in the bonded substrate;
  • Step 02 providing a silicon substrate, forming a closed cavity region filled with an infrared sensitive gas in the silicon substrate, and bonding the silicon substrate to the bonding substrate;
  • Step 03 bonding the piezoelectric conversion structure to the silicon substrate, and the piezoelectric conversion structure is in direct contact with the sealed cavity; wherein the piezoelectric conversion structure includes a bottom electrode, a top electrode, and A layer of piezoelectric material between the top and bottom electrodes.
  • the step 02 specifically includes:
  • Step 021 deposit an oxide layer on top of the silicon substrate
  • Step 022 etching an upper comb-shaped structure and a lower comb-tooth structure in the silicon substrate, wherein a top portion of the upper comb-like structure and a top portion of the lower comb-tooth structure are in contact with the oxide layer;
  • the bottom of the upper comb-like structure is higher than the bottom of the lower comb-like structure;
  • Step 023 bonding the bonded substrate to the bottom of the silicon substrate
  • Step 024 etching a groove in the oxide layer corresponding to the top of the comb tooth of the upper comb-shaped structure
  • Step 025 filling a conductive material in the groove, and planarizing the top of the conductive material flush with the top of the oxide layer to form a contact block;
  • Step 026 removing the oxide layer corresponding to the upper portion of the sealed cavity region, leaving the oxide layer on the surface of the edge region of the silicon substrate outside the sealed cavity region.
  • the step 01 specifically includes: first, forming an infrared window layer in the bonded substrate; then, etching a plurality of trenches in the infrared window layer, the trench is located at the lower comb Below the region between the adjacent comb teeth and below the silicon substrate outside the sealed cavity, and not below the comb teeth of the lower comb-like structure; The infrared absorbing layer is deposited in the trenches.
  • the step 01 specifically includes: sequentially forming an infrared absorbing layer and an infrared window layer in the bonding substrate; and providing an SOI substrate; the SOI substrate has a bottom silicon layer, an interlayer dielectric, and a top Silicon layer
  • the step 02 specifically includes:
  • Step 021' inverting the SOI substrate to form the first cavity and the second cavity in the bottom silicon layer in a vacuum environment
  • Step 022' depositing the reflective layer in the first cavity under a vacuum environment
  • Step 023' bonding the bottom of the bonded substrate to the bottom silicon layer in a vacuum environment, and filling the first cavity and the second cavity during bonding Said infrared sensitive gas;
  • the step 03 specifically includes:
  • Step 031 ′ etching a first opening in the bonding substrate, the first opening penetrating the bonding substrate, and an area between the first cavity and the second cavity Above
  • Step 032 ′ reversing the SOI substrate, forming the first MOS device having the first conductivity type channel and the second having the second conductivity type channel in the top silicon layer MOS device;
  • Step 033 ′ etching a second opening in the top silicon layer and the interlayer dielectric and corresponding to the second cavity, and vacuuming the infrared sensitive gas in the second cavity through the second opening Released
  • Step 034' depositing a metal front medium in a vacuum environment on the SOI substrate completing the step 033'; the metal front medium seals the top of the second opening, so that the second cavity is vacuumed state;
  • Step 035 ′ forming the back channel interconnection layer on the metal front dielectric, and then engraving in the back channel interconnection layer, the metal front dielectric, the top silicon layer, and the interlayer dielectric
  • the third opening is etched; the third opening corresponds to an area above the first cavity and the second cavity.
  • the infrared detector pixel structure of the present invention and the preparation method thereof by bonding a bonding substrate at the bottom of a silicon substrate, and utilizing an infrared window material layer in the bonding substrate to selectively pass infrared light of a desired wavelength band
  • the infrared absorbing layer in the bonded substrate is used to absorb part of the infrared light, and a closed cavity filled with an infrared sensitive gas is disposed in the silicon substrate, and the piezoelectric conversion structure is bonded on the closed cavity, when infrared sensitive
  • the gas is absorbed into the infrared light, the piezoelectric conversion structure is squeezed, and the piezoelectric signal generated by the piezoelectric conversion structure is changed, thereby detecting the infrared light; further, the upper comb is disposed in the silicon substrate.
  • the infrared absorbing layer absorbs the infrared light and generates heat to the infrared sensitive gas
  • the infrared sensitive gas absorbs After the infrared light, it will generate heat itself, so that the infrared sensitive gas expands, resulting in relative displacement of the upper comb-tooth structure and the lower comb-tooth structure, so that the vertical Changes in capacitance of the capacitive structure is generated, while IR-sensitive expansion gas is also led to a piezoelectric signal generated piezoelectric conversion structure changes, enabling detection of infrared light.
  • FIG. 1 is a schematic view showing the structure of an infrared detector pixel according to a preferred embodiment of the present invention
  • FIG. 2 is a schematic diagram of a path for preparing a pixel structure of an infrared detector according to a preferred embodiment of the present invention
  • 3-12 are schematic diagrams showing respective preparation steps of a method for preparing an infrared detector pixel structure according to a preferred embodiment of the present invention.
  • Figure 13 is a schematic view showing the structure of an infrared detector pixel according to a preferred embodiment of the present invention.
  • FIG. 14 is a schematic flow chart of a method for fabricating an image structure of an infrared detector according to a preferred embodiment of the present invention.
  • 15-23 are schematic diagrams showing preparation steps of a method for preparing an image structure of an infrared detector according to a preferred embodiment of the present invention.
  • FIG. 24 is a flow chart showing a method for fabricating an infrared detector pixel structure according to another preferred embodiment of the present invention.
  • the infrared detector pixel structure of the present invention comprises a bonded substrate, a silicon substrate bonded to the bonded substrate, and a piezoelectric conversion structure on the silicon substrate; wherein, in the bonded substrate An infrared absorbing layer; the infrared absorbing layer is for absorbing infrared light; the silicon substrate comprises a closed cavity region filled with an infrared sensitive gas; and the piezoelectric conversion structure is located above the closed cavity region of the silicon substrate; After the infrared light enters the infrared absorption layer, part of the infrared light is absorbed by the infrared absorption layer, and a part of the infrared light passes through the infrared absorption layer into the closed cavity, and is absorbed by the infrared sensitive gas in the closed cavity, and the infrared sensitive gas in the closed cavity is sealed.
  • the infrared absorption layer absorbs the infrared light to generate heat to be transmitted to the infrared sensitive gas, causing the infrared sensitive gas to expand and act on the piezoelectric conversion structure, resulting in a piezoelectric signal formed by the piezoelectric conversion structure.
  • a change is made to achieve detection of infrared light.
  • the piezoelectric conversion structure is constructed of a piezoelectric material utilizing a change in electrical signals generated by the piezoelectric material when subjected to stress; in one embodiment, piezoelectric The conversion structure is formed by using a MOS device, and the electrical signal generated when the channel of the MOS device is subjected to stress is changed; in one embodiment, the piezoelectric conversion structure and the piezoelectric conversion structure may be further disposed inside the sealed cavity. It is constructed by a capacitor structure, which utilizes a change in the electrical signal generated by the capacitor structure when subjected to stress.
  • the top and side walls in the closed cavity may be provided with a reflective layer for reflecting infrared light entering the closed cavity into the closed cavity and being absorbed by the infrared sensitive gas, which is not absorbed by the infrared gas. The light is in turn absorbed by the infrared absorbing layer at the bottom of the closed cavity.
  • the silicon substrate having the closed cavity is the bottom silicon layer of the SOI substrate, and the bottom silicon layer further has an intermediate dielectric layer and a top silicon layer; the piezoelectric conversion structure is located in the bottom silicon layer.
  • Above the closed cavity comprising a first MOS device having a channel of a first conductivity type and a second MOS device having a channel of a second conductivity type surrounding a periphery of the first MOS device; a first conductivity type and a second conductivity type Conversely; the first conductivity type channel corresponds to the upper intermediate region of the closed cavity, and the second conductivity type channel spans over a portion of the interlayer dielectric above the first closed cavity sidewall and surrounds the first conductivity type channel Settings.
  • openings may be provided in the bonded substrate other than below the closed cavity for isolating adjacent pixel cells; a silicon substrate outside the closed cavity An opening may also be provided for isolating the closed cavity from the adjacent pixel structure; an opening may be provided in the edge region of the piezoelectric conversion structure outside the closed cavity for the piezoelectric conversion structure and the adjacent image The meta-structure is isolated; thus avoiding crosstalk between adjacent cells.
  • the infrared detecting pixel structure includes: a bonding substrate 01, a silicon substrate 02 on the bonding substrate 01, and a closed cavity region in the silicon substrate 02 (dashed frame) Shown) a piezoelectric member on the silicon substrate 02 (the piezoelectric member is the piezoelectric conversion structure of the embodiment, and the piezoelectric conversion structure of the other embodiment of the present invention is not limited to the piezoelectric member), in the closed cavity region
  • the surface of the edge region of the silicon substrate 02 other than the upper portion has an oxide layer 03 which isolates the edge region of the silicon substrate 02 from the piezoelectric member.
  • the bonded substrate 01 has an infrared window layer 11 and an infrared absorbing layer 12 in this order from bottom to top.
  • the infrared window layer 11 has a plurality of trenches, and the infrared absorbing layer 12 is filled in a plurality of trenches; the trench is located in the lower comb
  • the structure 021 is below the adjacent comb teeth and below the silicon substrate 02 outside the sealed cavity, and is not located below the comb teeth of the lower comb-shaped structure 021; the keys outside the closed cavity
  • a first opening K1 may be disposed in the substrate 01 for isolating between adjacent pixel units;
  • the piezoelectric conversion structure has a bottom electrode 05, a piezoelectric material layer 06 and a top electrode 07, and a dielectric protective layer 08 on the top of the top electrode 07.
  • the dielectric protective layer 08 covers the entire piezoelectric member, and the piezoelectric material layer 06 corresponds to Above the upper comb-shaped structure 022 and the edge region of the piezoelectric material layer 06 is not located in the corresponding region above the oxide layer 03, the edge region of the bottom electrode 05 covers the oxide layer 03, and the length of the top electrode 07 is smaller than that of the piezoelectric material layer 06
  • the length of the dielectric protective layer 08 overlying the entire piezoelectric conversion structure forms a multi-step structure; the piezoelectric conversion structure corresponding to the oxide layer 03 and the upper portion thereof also has a third opening K3 for pressing
  • the electrical conversion structure is isolated from the adjacent pixel structure;
  • the closed cavity region of the silicon substrate 02 has an upper comb-shaped structure 022 and a lower comb-shaped structure 021, and the top of the upper comb-shaped structure 022 is in contact with the bottom electrode 05, and the bottom electrode 05 is connected below.
  • the comb teeth of the lower comb-tooth structure 021 are disposed between two phases; the bottom of the upper comb-tooth structure 022 has a gap between the bottom and the infrared absorbing layer 12; the bottom of the cavity between the comb teeth of the lower comb-shaped structure 021 and infrared absorption
  • the layer 12 is in contact connection; the cavity between the upper comb-tooth structure 022 and the lower comb-tooth structure 021 is
  • a second opening K2 may be provided in the silicon substrate 02 outside the closed cavity for isolating the closed cavity from the adjacent pixel structure; here, the height of the upper comb-shaped structure 022 and the lower comb-shaped structure 021
  • the ratio can be (10 ⁇ 40): 1.
  • the bonded substrate 01 further has an interconnection circuit, and the comb teeth of the adjacent upper comb-tooth structure 022 and the comb teeth of the lower comb-tooth structure 021 and the infrared sensitive gas therebetween constitute a vertical
  • the capacitor structure, the comb teeth of the lower comb-tooth structure 021 are electrically connected to the interconnect circuit to form a lower electrode of the vertical capacitor structure, and the bottom electrode 05 of the piezoelectric component serves as an upper electrode of the vertical capacitor structure;
  • the pressure of the infrared sensitive gas acts on the piezoelectric conversion structure and the vertical capacitance structure, resulting in a change in the capacitance signal of the vertical capacitance structure and a piezoelectric signal generation of the piezoelectric material layer.
  • the piezoelectric signal generated by the change of the piezoelectric signal is transmitted to the external circuit through the top electrode and the bottom electrode, and the changed capacitance signal is transmitted to the external circuit through the interconnection circuit and the bottom electrode, thereby realizing the detection of the infrared light; meanwhile, due to the pressure
  • the electrical signal and the capacitive signal change at the same time to obtain a strong change signal, which improves the sensitivity of the detector.
  • the preparation method of the infrared detector of this embodiment will be further described in detail below.
  • the structure of the prepared infrared detector is as described above; please refer to FIG. 2, this The preparation method of the embodiment includes:
  • Step 01 providing a bonded substrate, forming an infrared absorbing layer in the bonded substrate;
  • an infrared window layer 11 is formed in the bonded substrate 01; then, a plurality of trenches are etched in the infrared window layer 11; the trench should be located in the lower comb-like structure phase Below the region between the adjacent comb teeth and below the silicon substrate outside the sealed cavity, and not under the comb teeth of the lower comb-like structure; and then depositing the infrared absorbing layer 12 in the plurality of trenches; Then, a first opening K1 is formed in the bonded substrate 01 outside the closed cavity for isolating between adjacent pixel units.
  • Step 02 providing a silicon substrate, forming a closed cavity region filled with an infrared sensitive gas in the silicon substrate, and bonding the silicon substrate to the bonding substrate;
  • step 02 includes:
  • Step 021 Please refer to FIG. 4, depositing an oxide layer 03 on top of the silicon substrate 02;
  • a second opening K2 is formed by etching in the silicon substrate 02 outside the closed cavity for isolating the closed cavity from the adjacent pixel structure; and then depositing the oxide layer 03 Wherein the surface of the edge region of the silicon substrate 02 outside the closed cavity region has an oxide layer 03;
  • Step 022 Referring to FIG. 5, the upper comb-tooth structure 022 and the lower comb-tooth structure 021 are etched in the silicon substrate 02, wherein the top of the upper comb-tooth structure 022 and the top of the lower comb-tooth structure 021 Contacting the oxide layer 03; the bottom of the upper comb-tooth structure 022 is higher than the bottom of the lower comb-tooth structure 021;
  • Step 023 Referring to FIG. 6, the bonded substrate 01 is bonded to the bottom of the silicon substrate 02;
  • Step 024 Referring to FIG. 7, the groove is etched in the oxide layer 03 corresponding to the top of the comb tooth of the upper comb-shaped structure 022;
  • Step 025 Please refer to FIG. 8, filling the recess with a conductive material, and flattening the top of the conductive material flush with the top of the oxide layer 03 to form the contact block 04;
  • Step 026 Referring to Figure 9, the oxide layer 03 corresponding to the upper portion of the sealed cavity region is removed, leaving the oxide layer 03 on the surface of the edge region of the silicon substrate 02 outside the closed cavity region;
  • Step 03 Bonding the piezoelectric conversion structure to the silicon substrate, and the piezoelectric conversion structure is in direct contact with the closed cavity.
  • a bottom electrode 05, a piezoelectric material layer 06, and a top electrode 07 are sequentially formed on a substrate, and a dielectric protective layer 08 may be formed on the top electrode 07 to constitute a piezoelectric layer. Conversion structure; then, referring to FIG. 11, the bottom of the prepared piezoelectric conversion structure (the bottom of the bottom electrode 05) is bonded to the oxide layer 03 and the top of the contact block 04;
  • a third opening K4 is etched in the oxide layer 03 and the piezoelectric member corresponding to the oxide layer 03 for isolating the piezoelectric conversion structure from the adjacent pixel structure.
  • the infrared detector pixel structure includes a bonded substrate 1 and an SOI substrate 2 having a bottom silicon layer 21, an interlayer dielectric 22 and a top silicon layer 23; wherein, there is a closed cavity
  • the silicon substrate of Q1 and Q2 is the bottom silicon layer 21 of the SOI substrate 2, and the interlayer silicon layer 21 and the top silicon layer 23 are further provided on the bottom silicon layer 21.
  • the bonded substrate 1 has an infrared absorbing layer 12 and an infrared window layer 11 in order from top to bottom, bonding
  • the substrate 1 further has a plurality of first openings K1 penetrating the entire bonding substrate 1 so as to form a region surrounded by the first opening K1 and a first opening K1 formed on the bonding substrate 1.
  • the infrared window layer 11 is for selecting a transmitted infrared light band; the infrared absorption layer 12 is for absorbing infrared light; the bonded substrate 1 herein may be a silicon substrate, and the material of the infrared window layer 11 may be For the material that transmits infrared light of a certain band, the infrared absorbing layer 12 may be the silicon substrate itself, so that only the infrared window material layer may be deposited on the silicon substrate during preparation; or may be sequentially performed on the silicon substrate. An infrared absorbing layer and an infrared window layer are formed.
  • the bottom silicon layer 21 of the SOI substrate 2 is located on the infrared absorbing layer 12 and seals the top of the first opening K1; the bottom silicon layer 21 includes a first closed cavity Q1 and a second portion around the first closed cavity Q1. a closed cavity Q2; a portion of the first closed cavity Q1 located on a portion of the infrared absorbing layer 12 of the region enclosed by the first opening K1, and a portion of the first closed cavity Q1 surrounded by the first opening K1
  • the infrared absorbing layer 12 is sealed; the second closed cavity Q2 is located on a portion of the infrared absorbing layer 12 outside the area enclosed by the first opening K1, and the bottom of the second closed cavity Q2 is surrounded by the first opening K1.
  • a portion of the infrared absorbing layer 12 outside the region is sealed; wherein the top portion and the sidewall of the first closed cavity Q1 have a reflective layer 3; the first closed cavity Q1 is filled with an infrared sensitive gas; and the infrared sensitive gas is generated by infrared irradiation.
  • the energy-changing gas for example, the infrared absorption peak of CO2, CO, CH4, or SO2 is in the range of 3 ⁇ m to 30 ⁇ m; the second closed cavity Q2 is in a vacuum state; the width of the first closed cavity Q1 is much larger than the second closed space The width of the cavity.
  • the SOI substrate 2 further has a metal front dielectric 6, a penetrating interlayer dielectric 22 and a bottom silicon layer 21, and corresponds to a second opening K2, a rear interconnect layer 7, and a penetrating layer above the second sealed cavity Q2.
  • the interlayer dielectric 22 sealing the tops of the first sealed cavity Q1 and the second sealed cavity Q2;
  • the type is opposite to the second conductivity type; for example, the first MOS device is a PMOS, the second MOS device is an NMOS, or the first MOS device is an NMOS, and the second MOS device is a PMOS.
  • the first conductive type channel C1 corresponds to an upper intermediate region of the first sealed cavity Q1
  • the second conductive type channel C2 spans over a portion of the interlayer dielectric 22 above the sidewall of the first sealed cavity Q1 and surrounds the first a conductive type channel C1 is disposed
  • a part of the metal front medium 6 is filled in the second opening K2, thereby sealing the top of the second closed cavity Q2, and the metal front medium 6 may also be completely filled in the second opening K2, but It is not possible to fill the second closed cavity Q2
  • the third opening K3 is located on a portion of the bottom silicon layer 21 between the first closed cavity Q1 and the second closed cavity Q2, and the bottom thereof is first sealed by the cavity Q1
  • a portion of the bottom silicon layer 21 between the second sealed cavity Q2 is sealed
  • the second opening K2 is disposed around the third opening K3
  • the third opening K3 is disposed around the second MOS device
  • the shape of the second conductive type channel C2 is The shape of the first closed cavity Q1 is
  • the first closed cavity Q1 is square, and the first conductive type channel C1 and the second conductive type channel C2 are arranged in a concentric manner, for example, the first sealed space is The cavity is circular, and the first conductivity type channel and the second conductivity type channel Concentric ring arrangement; as can be seen in Figure 1, the first conductivity type channel C1 is rectangular, the second conductivity type channel C2 is square, and the second conductivity type channel C2 is completely in the first closed cavity Q1 Above the sidewall, the sidewall of the first sealed cavity Q1 can be subjected to tensile stress to the second to conductive channel C2.
  • the arrangement of the first opening K1, the second opening K2 and the second closed cavity Q2 may isolate the first closed cavity Q1 from other regions; in particular, the first opening is for implementing the back device region of the bonded substrate 1. Separation from other areas; the second opening is to open the second closed cavity Q2, The gas is removed to form a vacuum; the second closed cavity is for isolating the device in the silicon substrate (bottom silicon layer 21) from other portions. Also, the third opening is for achieving isolation of the device region of the SOI substrate 2 from other regions.
  • the infrared light is filtered through the infrared window layer 11 to selectively obtain the infrared light of the desired wavelength band; the infrared light of the desired wavelength band enters the infrared absorption layer 12, and part of the infrared light is absorbed by the infrared light.
  • the layer 12 absorbs, the infrared light not absorbed by the infrared absorbing layer 12 enters the first closed cavity Q1, and the infrared light of the desired wavelength band enters the first closed cavity Q1, and the infrared sensitive gas in the first closed cavity Q1 is received.
  • the energy of the infrared light of the desired band is irradiated, and the intermediate portion of the first sealed cavity Q1 generates a compressive stress to the first conductive type channel C1, and the sidewall of the first sealed cavity Q1 generates the second conductive type channel C2.
  • the stress is pulled such that the first MOS device and the second MOS device respectively generate opposite electrical signals to form a differential output.
  • infrared light that is not absorbed by the infrared sensitive gas is reflected by the reflective layer 3 on the top and side walls of the first closed cavity Q1 into the first closed cavity Q1, and part of the reflected infrared light is absorbed by the infrared sensitive gas, and part of it is partially absorbed by the infrared sensitive gas.
  • the reflected infrared light enters the infrared absorbing layer 12 and is absorbed by the infrared absorbing layer 12.
  • a method of shielding a certain pixel or a certain area pixel may be adopted, so that a signal difference between the unmasked pixel generating electrical signal and the shielded pixel generating electrical signal is generated, which is convenient for removing. Noise, get an accurate and obvious signal.
  • the principle of the differential output is known to those skilled in the art and will not be described here.
  • Step 01 providing a bonded substrate, forming an infrared absorbing layer in the bonded substrate;
  • Step 02 providing a bottom silicon layer, forming a closed cavity filled with an infrared sensitive gas in the bottom silicon layer, and bonding the bottom silicon layer to the bonding substrate;
  • Step 03 Form a piezoelectric conversion structure on the bottom silicon layer.
  • the method for preparing the infrared detector pixel structure includes:
  • Step 101 sequentially forming an infrared absorbing layer and an infrared window layer in the bonding substrate; and providing an SOI substrate;
  • the SOI substrate has a bottom silicon layer, an interlayer dielectric, and a top silicon layer;
  • the infrared absorbing layer 12 and the infrared window layer 11 are sequentially deposited on the silicon substrate 1 (bonded substrate) by vapor deposition, and the provided SOI substrate 2 can be a conventional SOI substrate.
  • the provided SOI substrate 2 can be a conventional SOI substrate.
  • Step 102 Inverting the SOI substrate to form a first closed cavity and a second closed cavity in the bottom silicon layer in a vacuum environment;
  • the bottom silicon layer 21 of the SOI substrate 2 is directed upward, and the first sealed cavity Q1 and the second sealed cavity Q2 are etched by a plasma etching process.
  • the width of the first closed cavity Q1 is much larger than the width of the second closed cavity Q2.
  • Step 103 depositing a reflective layer in the first closed cavity under a vacuum environment
  • a reflective layer 3 is deposited in the first closed cavity Q1 by vacuum vapor deposition, and the reflective layer 3 may be a metal reflective layer.
  • the metal reflective layer has a fast transfer effect on heat, direct contact between the metal reflective layer and the infrared absorbing layer should be avoided. Therefore, when the reflective layer 3 is deposited in the first closed cavity Q1 in a vacuum environment, the first sealing is performed.
  • the height of the reflective layer 3 on the side wall of the cavity Q1 is lower than the height of the first closed cavity Q1, so that there is a gap between the top of the reflective layer 3 on the side wall of the first closed cavity Q1 and the infrared absorbing layer 12.
  • Step 104 Bonding the bottom of the bonded substrate to the bottom silicon layer in a vacuum environment, and filling the first closed cavity and the second closed cavity with an infrared sensitive gas during the bonding process;
  • the bottom of the silicon substrate 1 may be bonded to the bottom silicon layer 21 by a conventional bonding process, for the first closed cavity Q1 and the second closed cavity.
  • the process of filling the infrared sensitive gas in Q2 adopts a non-vacuum bonding process to pass infrared sensitive gas into the first closed cavity Q1 and the second closed cavity Q2; after bonding, the first closed cavity Q1 and the second
  • the sealed cavity Q2 is filled with infrared sensitive gas, and the second opening of the surface of the subsequent SOI silicon wafer is opened, and the infrared sensitive gas inside the second closed cavity is vacuumed and removed.
  • Step 105 etching a first opening in the bonding substrate, the first opening penetrating the bonding substrate, and located above a region between the first sealing cavity and the second sealing cavity;
  • the first opening K1 may be etched in the silicon substrate 1 (bonded substrate) by using a photolithography and plasma dry etching process; the first opening K1 penetrates the silicon substrate 1 (bonding the substrate) and above the area between the first closed cavity Q1 and the second closed cavity Q2
  • Step 106 re-inverting the SOI substrate to form a first MOS device having a first conductivity type channel and a second MOS device having a second conductivity type channel in the top silicon layer;
  • the top silicon layer 23 of the SOI substrate 2 is faced upward, and the first MOS device and the second MOS device are prepared by a conventional CMOS process, which will not be described herein. Thereby forming a first MOS device having a first conductivity type channel C1 and a second MOS device having a second conductivity type channel C2 in the top silicon layer 23;
  • Step 107 etching a second opening in the top silicon layer and the interlayer dielectric and corresponding to the second closed cavity, and evacuating the infrared sensitive gas in the second closed cavity through the second opening;
  • a second opening K2 may be etched in the top silicon layer 23 and the interlayer dielectric 22 and corresponding to the second sealed cavity Q2 by using a photolithography and etching process;
  • Step 108 depositing a metal front medium on the SOI substrate of step 107 in a vacuum environment; the metal front medium seals the top of the second opening, so that the second closed cavity is in a vacuum state;
  • the metal front medium 6 may be deposited by a vapor deposition method in a vacuum environment; by adjusting the process parameters, the metal front medium 6 seals the top of the second opening K2 at the second opening K2. Forming a vacuum state; the metal front medium 6 fills the upper portion of the second opening K2, or the metal front medium 6 fills the second opening K2, but the metal front medium 6 cannot be filled in the second closed cavity Q2;
  • Step 109 forming a rear interconnect layer on the metal front dielectric, and then etching a third opening in the back interconnect layer, the metal front dielectric, the top silicon layer, and the interlayer dielectric; the third opening corresponds to the first Above the area between the closed cavity and the second closed cavity.
  • the subsequent interconnect layer 7 can be prepared by a conventional process, which will not be described herein; a photolithography and etching process can be used for the interconnect layer 7, the metal front dielectric 6, and the top silicon.
  • a third opening K3 is etched into the layer 23 and the interlayer dielectric 22. The third opening K3 corresponds to an area above the area between the first closed cavity Q1 and the second closed cavity Q2.
  • Step 201 sequentially forming an infrared absorbing layer and an infrared window layer in the bonded substrate; and providing an SOI substrate; the SOI substrate has a bottom silicon layer, an interlayer dielectric, and a top silicon layer;
  • step 201 reference may be made to the description of step 101 in the foregoing embodiment, and details are not described herein again.
  • Step 202 Inverting the SOI substrate, and etching the first closed cavity and the second closed cavity in the bottom silicon layer;
  • step 202 reference may be made to the description of step 102 in the foregoing embodiment, and details are not described herein again.
  • Step 203 depositing a reflective layer in the first closed cavity; then, filling the first closed cavity with an infrared sensitive gas;
  • the reflective layer may be deposited in the first closed cavity by atmospheric pressure vapor deposition, and the reflective layer may be a metal reflective layer.
  • the metal reflective layer has a rapid transfer effect on heat, direct contact between the metal reflective layer and the infrared absorbing layer should be avoided, so that when the reflective layer is deposited in the first closed cavity in a vacuum environment, the first closed cavity is made
  • the height of the reflective layer of the side wall is lower than the height of the first closed cavity such that there is a gap between the top of the reflective layer of the first closed cavity sidewall and the infrared absorbing layer.
  • the first closed cavity is filled with the infrared sensitive gas
  • some infrared sensitive gas may inevitably enter the second closed cavity; but in the vacuum environment after the formation of the second opening and the deposition of the metal front medium Under the vacuum, some infrared sensitive gas in the second closed cavity can be extracted, so that the second closed cavity can be subsequently formed into a vacuum state;
  • Step 204 bonding the bottom of the bonded substrate to the bottom silicon layer under normal pressure
  • the first sealed cavity and the second closed cavity are filled with infrared sensitive gas
  • Step 205 etching a first opening in the bonding substrate, the first opening penetrating the bonding substrate, and located above a region between the first sealing cavity and the second sealing cavity;
  • Step 206 re-inverting the SOI substrate, forming a first MOS device having a first conductivity type channel and a second MOS device having a second conductivity type channel in the top silicon layer;
  • Step 207 vacuum etching the second opening in the top silicon layer and the interlayer dielectric and corresponding to the second closed cavity;
  • the process of opening the second opening and subsequently depositing the metal front dielectric layer is a vacuum environment, and therefore, if there is an infrared sensitive gas or other gas present in the second closed cavity, a vacuum can be formed.
  • Step 208 depositing a metal front medium on the SOI substrate of step 207 in a vacuum environment; the metal front medium seals the top of the second opening, thereby forming a vacuum state in the second sealed cavity;
  • Step 209 forming a rear interconnect layer on the metal front dielectric, and then etching a third opening in the back interconnect layer, the metal front dielectric, the top silicon layer, and the interlayer dielectric; the third opening corresponds to the first Above the area between the closed cavity and the second closed cavity.

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Abstract

一种红外探测器像元结构，包括键合衬底（01）、键合于键合衬底（01）上的硅衬底（02）以及位于硅衬底（02）上的压电转换结构（05,06,07）。键合衬底（01）中具有用于吸收红外光的红外吸收层（12）。硅衬底（02）中包括填充有红外敏感气体的密闭空腔区域，压电转换结构（05,06,07）位于硅衬底（02）的密闭空腔区域上方。当红外光经过红外窗口层被选择性透过后，一部分红外光被红外吸收层吸收，一部分红外光透过红外吸收层进入密闭空腔，被密闭空腔内的红外敏感气体吸收掉，密闭空腔内的红外敏感气体吸收了红外光之后产生热量以及红外吸收层吸收了红外光之后产生热量传递给红外敏感气体，使得红外敏感气体产生膨胀并且作用于压电转换结构（05,06,07），使得压电转换结构（05,06,07）形成的压电信号产生变化，从而实现对红外光的探测。还公开了一种制备红外探测器像元结构的方法。

Description

红外探测器像元结构及其制备方法
本申请要求于2016年7月18日提交中国专利局、申请号为_201610564866.4、名称为“红外探测器像元结构及其制备方法”，于2016 年7月18日提交中国专利局、申请号为201610564510.0、名称为“红外 探测器像元结构及其制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及半导体技术领域，具体涉及一种红外探测器像元结构及其制备方法。
技术背景
红外探测器是将入射的红外辐射信号转变为电信号输出的器件，其利用热敏元件检测物体的存在或移动，探测器手机外界的红外辐射进而聚集到红外传感器上，红外传感器采用热敏元件，热敏元件在接受了红外辐射温度发生变化时就会输出信号，将其转换为电信号，然后对电信号进行波形分析。传统红外探测器像元结构中仅使用一种类型热敏电阻，通常是负温度系数的非晶硅或者氧化钒，并通过电路将其变化的信号放大输出。
然而，采用热敏元件的探测器结构的灵敏度通常不是很高，且结构较为复杂，探测过程复杂，如果采用灵敏度较高的热敏元件则材料的成本昂贵。
因此，急需对现有红外探测器进行改进，来提高灵敏度，降低结构复杂度和成本。
发明概要
为了克服以上问题，本发明旨在提供一种红外探测器像元结构及其制备方法。
为了克服以上问题，本发明旨在提供一种红外探测器像元结构及其制备方法。
为了达到上述目的，本发明外探测器像元结构，包括键合衬底、键合于所述键合衬底上的硅衬底、以及位于硅衬底上的压电转换结构；其中，
所述键合衬底中具有红外吸收层；红外吸收层用于吸收红外光；
所述硅衬底中包括填充有红外敏感气体的密闭空腔区域；
所述压电转换结构位于所述硅衬底的所述密闭空腔区域上方；其中，
当红外光经过红外窗口层被选择性透过后，一部分红外光被红外吸收层吸收，一部分红外光透过红外吸收层进入密闭空腔，被密闭空腔内的红外敏感气体吸收掉，密闭空腔内的红外敏感气体吸收了红外光之后产生热量以及红外吸收层吸收了红外光之后产生热量传递给红外敏感气体，使得红外敏感气体产生膨胀并且作用于所述压电转换结构，所述压电转换结构形成的压电信号产生变化，从而实现对红外光的探测。
优选地，所述压电转换结构包括：底电极、顶电极以及位于顶电极和底电极之间的压电材料层；底电极键合于所述硅衬底和所述氧化层上；所述底电极与所述密闭空腔直接接触；当红外敏感气体产生膨胀并且作用于压电转换结构时，导致所述压电材料层形成的压电信号产生变化，通过所述顶电极和所述底电极将产生变化的压电信号传输到外部电路。
优选地，所述硅衬底的密闭空腔区域具有上梳齿状结构和下梳齿状结构，且所述上梳齿状结构的顶部与所述底电极相接触连接，所述底电极的下方连接有多个接触块，多个接触块的底部与所述上梳齿状结构的顶部相接触连接；上梳齿状结构的梳齿与下梳齿状结构的梳齿两两相间设置；上 梳齿状结构的底部与所述红外吸收层之间具有空隙；所述下梳齿状结构的梳齿之间的空腔底部与所述红外吸收层相接触连接；所述上梳齿状结构的和所述下梳齿状结构之间的空腔被所述底电极、所述氧化层、所述密闭空腔之外的所述硅衬底以及所述键合衬底密封，从而形成所述密闭空腔区域。
优选地，所述键合衬底中还具有互连电路，相邻的所述上梳齿状结构的梳齿和所述下梳齿状结构的梳齿及其之间的红外敏感气体构成竖直电容结构，所述下梳齿状结构的梳齿与所述互连电路相电连而构成所述竖直电容结构的下电极，所述压电转换结构的底电极作为所述竖直电容结构的上电极；当红外敏感气体产生膨胀时，红外敏感气体的压力作用于所述压电转换结构和所述竖直电容结构，导致所述竖直电容结构的电容信号产生变化以及导致所述压电材料层的压电信号产生变化，通过所述顶电极和所述底电极将产生变化的压电信号传输到外部电路，通过所述互连电路和所述底电极将产生变化的电容信号传输到外部电路，从而实现对红外光的探测。
优选地，所述红外窗口层具有多个沟槽，所述沟槽位于所述下梳齿状结构相邻的梳齿之间的下方以及所述密封空腔之外的所述硅衬底的下方，且不位于所述下梳齿状结构的梳齿的下方；所述红外吸收层填充与所述多个沟槽中。
优选地，所述压电转换结构的顶部还具有介质保护层，介质保护层覆盖于整个所述压电转换结构上。
优选地，在所述密闭空腔区域之外的所述硅衬底的边缘区域表面具有氧化层；所述压电转换结构中，所述压电材料层对应于所述上梳齿状结构上方且所述压电材料层的边缘区域不位于所述氧化层上方对应区域，所述底电极的边缘区域覆盖于所述氧化层上，所述顶电极的长度小于所述压电材料层的长度，从而使覆盖于整个所述压电转换结构上的所述介质保护层形成多级台阶状结构。
优选地，所述键合衬底中还具有位于所述红外吸收层底部的红外窗口层，用于选择透过的红外光波段。
优选地，所述压电转换结构包括具有第一导电类型沟道的第一MOS器件和围绕所述第一MOS器件外围的具有第二导电类型沟道的第二MOS器件；第一导电类型与第二导电类型相反；第一导电类型沟道对应于所述密闭空腔上方中间区域，第二导电类型沟道横跨于所述密闭空腔侧壁上方的部分层间介质上且围绕所述第一导电类型沟道设置。
为了达到上述目的，本发明提供了一种制备上述的红外探测器像元结构的方法，其包括：
步骤01：提供键合衬底，在键合衬底中形成所述红外吸收层；
步骤02：提供一硅衬底，在所述硅衬底中形成填充有红外敏感气体的密闭空腔区域，将硅衬底与所述键合衬底相键合；
步骤03：将所述压电转换结构键合于所述硅衬底上，且所述压电转换结构与密闭空腔直接接触；其中，所述压电转换结构包括底电极、顶电极以及位于顶电极和底电极之间的压电材料层。
优选地，所述步骤02具体包括：
步骤021：在所述硅衬底顶部沉积氧化层；
步骤022：在所述硅衬底中刻蚀出上梳齿状结构和下梳齿状结构，其中，上梳齿状结构的顶部和下梳齿状结构的顶部与所述氧化层相接触；所述上梳齿状结构的底部高于所述下梳齿状结构的底部；
步骤023：将所述键合衬底与所述硅衬底的底部相键合；
步骤024：在对应于所述上梳齿状结构的梳齿顶部的所述氧化层中刻蚀出凹槽；
步骤025：在凹槽中填充导电材料，并且平坦化导电材料顶部与氧化层顶部齐平，以形成接触块；
步骤026：将对应于所述密封空腔区域上方的所述氧化层去除，保留所述密闭空腔区域之外的所述硅衬底的边缘区域表面的所述氧化层。
优选地，所述步骤01具体包括：首先，在键合衬底中形成一红外窗口层；然后，在所述红外窗口层中在所述刻蚀出多个沟槽，沟槽位于下梳齿状结构相邻的梳齿之间区域的下方以及所述密封空腔之外的所述硅衬底的下方，且不位于所述下梳齿状结构的梳齿的下方；再在所述多个沟槽中沉积所述红外吸收层。
优选地，所述步骤01具体包括：在所述键合衬底中依次形成红外吸收层和红外窗口层；且提供一SOI衬底；所述SOI衬底具有底部硅层、层间介质和顶部硅层；
所述步骤02具体包括：
步骤021’：将所述SOI衬底倒置，在真空环境下在所述底部硅层中形成所述第一空腔和所述第二空腔；
步骤022’：在真空环境下在所述第一空腔中沉积所述反射层；
步骤023’：在真空环境下将所述键合衬底的底部与所述底部硅层键合，且在键合过程中，向所述第一空腔和所述第二空腔中填充所述红外敏感气体；
所述步骤03具体包括：
步骤031’：在所述键合衬底中刻蚀出第一开口，第一开口穿透所述键合衬底，且位于所述第一空腔和所述第二空腔之间的区域上方；
步骤032’：将所述SOI衬底再反转过来，在所述顶部硅层中形成所述具有第一导电类型沟道的第一MOS器件和所述具有第二导电类型沟道的第二MOS器件；
步骤033’：在所述顶部硅层和所述层间介质中且对应于所述第二空腔上方刻蚀出第二开口，通过第二开口抽真空将第二空腔中的红外敏感气体释放出来；
步骤034’：在完成所述步骤033’的SOI衬底上在真空环境下沉积金属前介质；金属前介质将所述第二开口顶部封住，从而第二空腔中呈真空状 态；
步骤035’：在所述金属前介质上形成所述后道互连层，然后，在所述后道互连层、所述金属前介质、所述顶部硅层和所述层间介质中刻蚀出所述第三开口；所述第三开口对应于所述第一空腔和所述第二空腔之间的区域上方。
本发明的红外探测器像元结构及其制备方法，通过在硅衬底底部键合了键合衬底，利用键合衬底中的红外窗口材料层来使所需波段的红外光选择性透过，利用键合衬底中的红外吸收层来吸收部分的红外光，在硅衬底中设置填充有红外敏感气体的密闭空腔，在密闭空腔上键合压电转换结构，当红外敏感气体吸收到红外光发生膨胀时，会挤压压电转换结构，导致压电转换结构产生的压电信号发生变化，从而实现对红外光的探测；进一步的，在硅衬底中设置上梳齿状结构和下梳齿状结构，从而同时构成竖直电容结构和填充有红外敏感气体的密闭空腔；红外吸收层吸收了红外光之后会产生热量传递给红外敏感气体，同时红外敏感气体吸收了红外光之后自身也会产生热量，从而红外敏感气体发生膨胀，导致上梳齿状结构和下梳齿状结构产生相对位移，使得竖直电容结构的电容产生变化，同时，红外敏感气体的膨胀也导致压电转换结构的压电信号产生变化，从而实现对红外光的探测。
附图说明
图1为本发明的一个较佳实施例的红外探测器像元结构的示意图
图2为本发明的一个较佳实施例的红外探测器像元结构的制备方法的路程示意图
图3-12为本发明的一个较佳实施例的红外探测器像元结构的制备方法的各制备步骤的示意图
图13为本发明的一个较佳实施例的红外探测器像元结构的示意图
图14为本发明的一个较佳实施例的红外探测器像元结构的制备方法的流程示意图
图15-23为本发明的一个较佳实施例的红外探测器像元结构的制备方法的各制备步骤示意图
图24为本发明的另一个较佳实施例的红外探测器像元结构的制备方法的流程示意图
具体实施方式
为使本发明的内容更加清楚易懂，以下结合说明书附图，对本发明的内容作进一步说明。当然本发明并不局限于该具体实施例，本领域内的技术人员所熟知的一般替换也涵盖在本发明的保护范围内。
本发明的红外探测器像元结构，包括键合衬底、键合于所述键合衬底上的硅衬底、以及位于硅衬底上的压电转换结构；其中，键合衬底中具有红外吸收层；红外吸收层用于吸收红外光；硅衬底中包括填充有红外敏感气体的密闭空腔区域；压电转换结构位于硅衬底的所述密闭空腔区域上方；其中，当红外光进入红外吸收层后，一部分红外光被红外吸收层吸收，一部分红外光透过红外吸收层进入密闭空腔，被密闭空腔内的红外敏感气体吸收掉，密闭空腔内的红外敏感气体吸收了红外光之后产生热量以及红外吸收层吸收了红外光之后产生热量传递给红外敏感气体，导致红外敏感气体产生膨胀并且作用于所述压电转换结构，导致压电转换结构形成的压电信号产生变化，从而实现对红外光的探测。
在本发明的一个实施例中，压电转换结构是采用压电材料构成的，利用的是压电材料在受到应力时产生的电信号发生改变；在一个实施例中，压电 转换结构是采用MOS器件构成的，利用MOS器件的沟道在受到应力时产生的电信号发生改变；在一个实施例中，在密闭空腔内部还可以再设置压电转换结构，压电转换结构是采用电容结构构成的，利用的是电容结构在受到应力时产生的电信号发生改变。在一个实施例中，在密闭空腔内的顶部和侧壁可以设置反射层，用于将进入密闭空腔的红外光反射到密闭空腔内被红外敏感气体吸收，没有被红外气体吸收的红外光进而被密闭空腔底部的红外吸收层吸收。
本发明的另一个实施例中，具有密闭空腔的硅衬底为SOI衬底的底部硅层，底部硅层之上还具有中间介质层和顶部硅层；压电转换结构位于底部硅层中的密闭空腔上方，其包括具有第一导电类型沟道的第一MOS器件和围绕第一MOS器件外围的具有第二导电类型沟道的第二MOS器件；第一导电类型与第二导电类型相反；第一导电类型沟道对应于密闭空腔上方中间区域，第二导电类型沟道横跨于所述第一密闭空腔侧壁上方的部分层间介质上且围绕第一导电类型沟道设置。
本发明中的一些实施例中，在密闭空腔下方之外的键合衬底中可以设置有开口，用于将相邻像元单元之间进行隔离；在密闭空腔之外的硅衬底中也可以设置开口，用于将密闭空腔与相邻像元结构隔离；在密闭空腔上方之外的压电转换结构边缘区域也可以设置开口，用于将压电转换结构与相邻像元结构隔离；从而避免相邻像元之间的串扰。
实施例一
以下结合附图1-12和具体实施例对本发明作进一步详细说明。需说明的是，附图均采用非常简化的形式、使用非精准的比例，且仅用以方便、清 晰地达到辅助说明本实施例的目的。
请参阅图1，本实施例中，红外探测像元结构包括：键合衬底01、位于键合衬底01上的硅衬底02、位于硅衬底02中的密闭空腔区域(虚线框所示)、位于硅衬底02上的压电部件(压电部件为本实施例的压电转换结构，本发明其它实施例的压电转换结构不限于压电部件)，在密闭空腔区域上方之外的硅衬底02边缘区域的表面具有氧化层03，氧化层03将硅衬底02边缘区域与压电部件相隔离开来。
键合衬底01中从下往上依次具有红外窗口层11和红外吸收层12，红外窗口层11具有多个沟槽，红外吸收层12填充于多个沟槽中；沟槽位于下梳齿状结构021相邻的梳齿之间的下方以及密封空腔之外的硅衬底02的下方，且不位于下梳齿状结构021的梳齿的下方；在密闭空腔下方之外的键合衬底01中可以设置有第一开口K1，用于将相邻像元单元之间进行隔离；
压电转换结构具有底电极05、压电材料层06和顶电极07，在顶电极07的顶部还具有介质保护层08，介质保护层08覆盖于整个压电部件上，压电材料层06对应于上梳齿状结构022上方且压电材料层06的边缘区域不位于氧化层03上方对应区域，底电极05的边缘区域覆盖于氧化层03上，顶电极07的长度小于压电材料层06的长度，从而使覆盖于整个压电转换结构上的介质保护层08形成多级台阶状结构；对应于氧化层03及其上方的压电转换结构中还具有第三开口K3，用于将压电转换结构与相邻像元结构之间隔离开来；
硅衬底02的密闭空腔区域具有上梳齿状结构022和下梳齿状结构021，且上梳齿状结构022的顶部与底电极05相接触连接，底电极05的下方连接 有多个接触块04，多个接触块04的底部与上梳齿状结构022的顶部相接触连接；接触块04的材料与底电极05的材料相同；上梳齿状结构022的梳齿与下梳齿状结构021的梳齿两两相间设置；上梳齿状结构022的底部与红外吸收层12之间具有空隙；下梳齿状结构021的梳齿之间的空腔底部与红外吸收层12相接触连接；上梳齿状结构022的和下梳齿状结构021之间的空腔被底电极05、氧化层03、密闭空腔之外的硅衬底02以及键合衬底01密封，从而形成密闭空腔区域；这里，压电部件的底电极05键合于接触块04、氧化层03上，底电极05的底部与氧化层03的顶部齐平。在密闭空腔之外的硅衬底02中可以设置第二开口K2，用于将密闭空腔与相邻像元结构隔离；这里，上梳齿状结构022与下梳齿状结构021的高度比例可以为(10～40):1。
本实施例中，键合衬底01中还具有互连电路，相邻的上梳齿状结构022的梳齿和下梳齿状结构021的梳齿及其之间的红外敏感气体构成竖直电容结构，下梳齿状结构021的梳齿与互连电路相电连而构成竖直电容结构的下电极，压电部件的底电极05作为竖直电容结构的上电极；
因此，当红外敏感气体产生膨胀时，红外敏感气体的压力作用于压电转换结构和所述竖直电容结构，导致竖直电容结构的电容信号产生变化以及导致压电材料层的压电信号产生变化，通过顶电极和底电极将产生变化的压电信号传输到外部电路，通过互连电路和底电极将产生变化的电容信号传输到外部电路，从而实现对红外光的探测；同时，由于压电信号和电容信号同时发生变化来得到了较强的变化信号，提高了探测器的灵敏度。
请参阅图2-12，以下对本实施例的红外探测器的制备方法进一步详细说明。本实施例中，所制备的红外探测器的结构如上述描述；请参阅图2，本 实施例的制备方法包括：
步骤01：提供键合衬底，在键合衬底中形成红外吸收层；
具体的，请参阅图3，首先，在键合衬底01中形成红外窗口层11；然后，在红外窗口层11中在刻蚀出多个沟槽；沟槽应当位于下梳齿状结构相邻的梳齿之间区域的下方以及密封空腔之外的硅衬底的下方，且不位于下梳齿状结构的梳齿的下方；再在所多个沟槽中沉积红外吸收层12；然后，在密闭空腔下方之外的键合衬底01中形成第一开口K1，用于将相邻像元单元之间进行隔离。
步骤02：提供一硅衬底，在硅衬底中形成填充有红外敏感气体的密闭空腔区域，将硅衬底与键合衬底相键合；
具体的，本步骤02包括：
步骤021：请参阅图4，在硅衬底02顶部沉积氧化层03；
这里，在沉积氧化层03之前，先在密闭空腔之外的硅衬底02中刻蚀形成第二开口K2，用于将密闭空腔与相邻像元结构隔离；然后再沉积氧化层03；其中，在密闭空腔区域之外的硅衬底02的边缘区域表面具有氧化层03；
步骤022：请参阅图5，在硅衬底02中刻蚀出上梳齿状结构022和下梳齿状结构021，其中，上梳齿状结构022的顶部和下梳齿状结构021的顶部与氧化层03相接触；上梳齿状结构022的底部高于下梳齿状结构021的底部；
步骤023：请参阅图6，将键合衬底01与硅衬底02的底部相键合；
步骤024：请参阅图7，在对应于上梳齿状结构022的梳齿顶部的氧化层03中刻蚀出凹槽；
步骤025：请参阅图8，在凹槽中填充导电材料，并且平坦化导电材料顶部与氧化层03顶部齐平，以形成接触块04；
步骤026：请参阅图9，将对应于密封空腔区域上方的氧化层03去除，保留密闭空腔区域之外的硅衬底02的边缘区域表面的氧化层03；
步骤03：将压电转换结构键合于硅衬底上，且压电转换结构与密闭空腔直接接触。
具体的，包括：首先，请参阅图10，在一衬底上依次形成底电极05、压电材料层06和顶电极07，还可以在顶电极07上形成介质保护层08，从而构成压电转换结构；然后，请参阅图11，将制备好的压电转换结构底部(底电极05底部)与氧化层03、接触块04顶部相键合；
最后，请参阅图12，在氧化层03以及对应于氧化层03上方的压电部件中刻蚀出第三开口K4，用于将压电转换结构与相邻像元结构之间隔离开来。
实施例二
以下结合附图13-24和具体实施例对本发明作进一步详细说明。需说明的是，附图均采用非常简化的形式、使用非精准的比例，且仅用以方便、清晰地达到辅助说明本实施例的目的。
请参阅图13，本实施例中，红外探测器像元结构包括键合衬底1和具有底部硅层21、层间介质22和顶部硅层23的SOI衬底2；其中，具有密闭空腔Q1和Q2的硅衬底为SOI衬底2的底部硅层21，底部硅层21之上还具有层间介质22和顶部硅层23。
键合衬底1中从上到下依次具有红外吸收层12和红外窗口层11，键合 衬底1还具有若干第一开口K1，第一开口K1穿透整个键合衬底1，从而在键合衬底1上形成第一开口K1所围成的区域和第一开口K1所围成的区域外的区域；红外窗口层11用于选择透过的红外光波段；红外吸收层12用于吸收红外光；这里的键合衬底1可以为硅衬底，红外窗口层11的材料可以为透过某个波段红外光的材料，红外吸收层12可以为硅衬底本身，这样在制备时，只需在硅衬底上沉积红外窗口材料层即可；也可以在硅衬底上依次形成红外吸收层和红外窗口层。
SOI衬底2的底部硅层21位于红外吸收层12上，且将第一开口K1顶部封住；底部硅层21中包括第一密闭空腔Q1和位于第一密闭空腔Q1周围的第二密闭空腔Q2；第一密闭空腔Q1位于第一开口K1所围成的区域的部分红外吸收层12上，且第一密闭空腔Q1的底部被第一开口K1所围成的区域的部分红外吸收层12封住；第二密闭空腔Q2位于第一开口K1所围成的区域外的部分红外吸收层12上，且第二密闭空腔Q2的底部被第一开口K1所围成的区域外的部分红外吸收层12封住；其中，第一密闭空腔Q1顶部和侧壁具有反射层3；第一密闭空腔Q1内填充有红外敏感气体；红外敏感气体是受到红外照射而产生能量变化的气体，例如，CO2，CO，CH4，或SO2等红外吸收峰在3μm-30μm波段；第二密闭空腔Q2内为真空状态；第一密闭空腔Q1的宽度远大于第二密闭空腔的宽度。
SOI衬底2上还具有金属前介质6、穿透层间介质22和底部硅层21且对应于第二密闭空腔Q2上方的第二开口K2、后道互连层7、以及穿透层间介质层22、顶部硅层23、金属前介质6和后道互连层7的第三开口K3；在第一密闭空腔Q1上方的顶部硅层23中具有第一导电类型沟道C1的第一 MOS器件和围绕第一MOS器件外围的具有第二导电类型沟道C2的第二MOS器件；层间介质22将第一密闭空腔Q1和第二密闭空腔Q2的顶部封住；第一导电类型与第二导电类型相反；例如，第一MOS器件为PMOS，第二MOS器件为NMOS，或者第一MOS器件为NMOS，第二MOS器件为PMOS。
其中，第一导电类型沟道C1对应于第一密闭空腔Q1上方中间区域，第二导电类型沟道C2横跨于第一密闭空腔Q1侧壁上方的部分层间介质22上且围绕第一导电类型沟道C1设置；部分金属前介质6填充于第二开口K2中，从而将第二密闭空腔Q2的顶部封住，金属前介质6还可以全部填充于第二开口K2中，但不可以填入第二密闭空腔Q2中；第三开口K3位于第一密闭空腔Q1和第二密闭空腔Q2之间的部分底部硅层21上，且其底部被第一密闭空腔Q1和第二密闭空腔Q2之间的部分底部硅层21封住；第二开口K2围绕第三开口K3设置；第三开口K3围绕第二MOS器件设置；第二导电类型沟道C2的形状与第一密闭空腔Q1的形状一致，例如，第一密闭空腔Q1呈方形，则第一导电类型沟道C1和第二导电类型沟道C2呈同心回型设置，再例如，第一密闭空腔呈圆形，则第一导电类型沟道和第二导电类型沟道呈同心环型设置；从如图1中可以看到，第一导电类型沟道C1为矩形，第二导电类型沟道C2为方形，第二导电类型沟道C2完全在第一密闭空腔Q1侧壁上方，从而能够第一密闭空腔Q1侧壁对第二到导电型沟道C2产生拉应力。第一开口K1、第二开口K2和第二密闭空腔Q2的设置可以将第一密闭空腔Q1与其它区域隔离开来；具体的，第一开口为了实现键合衬底1的背面器件区域与其它区域的隔离；第二开口是为了打开第二密闭空腔Q2， 并将其中气体去除后形成真空；第二密闭空腔是为了将硅衬底体内(底部硅层21)形成器件与其它部分相隔离。同样，第三开口是为了实现SOI衬底2的器件区域与其它区域的隔离。
红外探测器像元进行探测时，红外光穿过红外窗口层11被过滤后，选择性地得到所需波段的红外光；所需波段的红外光进入红外吸收层12，部分红外光被红外吸收层12吸收，没有被红外吸收层12吸收的红外光进入第一密闭空腔Q1中，所需波段的红外光进入第一密闭空腔Q1中，第一密闭空腔Q1中的红外敏感气体受到所需波段的红外光照射而产生能量变化，第一密闭空腔Q1中间区域对第一导电类型沟道C1产生压应力，第一密闭空腔Q1的侧壁对第二导电类型沟道C2产生拉应力，从而使第一MOS器件和第二MOS器件分别产生相反的电信号，形成差分输出。同时，没有被红外敏感气体吸收的红外光被第一密闭空腔Q1顶部和侧壁的反射层3反射到第一密闭空腔Q1中，部分被反射的红外光被红外敏感气体吸收，部分被反射的红外光进入红外吸收层12被红外吸收层12吸收。在红外探测器探测时，可以采用屏蔽某一像元或某一区域像元的方式，使得未被屏蔽的像元产生电信号和屏蔽的像元产生电信号之间产生信号差，这样便于去除噪声，得到准确明显的信号。关于差分输出的原理是本领域技术人员可以知晓的，这里不再赘述。
本实施例中针对上述红外探测器像元结构的制备方法，可以包括：
步骤01：提供键合衬底，在键合衬底中形成红外吸收层；
步骤02：提供一底部硅层，在底部硅层中形成填充有红外敏感气体的密闭空腔，将底部硅层与键合衬底相键合；
步骤03：将压电转换结构形成于底部硅层上。
请参阅图14，本实施例中，制备上述红外探测器像元结构的制备方法具体包括：
步骤101：在键合衬底中依次形成红外吸收层和红外窗口层；且提供一SOI衬底；SOI衬底具有底部硅层、层间介质和顶部硅层；
具体的，请参阅图15，采用气相沉积法在硅衬底1(键合衬底)上依次沉积红外吸收层12和红外窗口层11，所提供的SOI衬底2可以采用常规SOI衬底，具有底部硅层21、层间介质22和顶部硅层23。
步骤102：将SOI衬底倒置，在真空环境下在底部硅层中形成第一密闭空腔和第二密闭空腔；
具体的，请参阅图16，使SOI衬底2的底部硅层21朝上，采用等离子体刻蚀工艺来刻蚀第一密闭空腔Q1去和第二密闭空腔Q2。第一密闭空腔Q1的宽度远大于第二密闭空腔Q2的宽度。
步骤103：在真空环境下在第一密闭空腔中沉积反射层；
具体的，请参阅图17，采用真空气相沉积法在第一密闭空腔Q1中沉积反射层3，反射层3可以为金属反射层。考虑到金属反射层具有对热量的快速传递效果，应当避免金属反射层与红外吸收层的直接接触，因此，在真空环境下在第一密闭空腔Q1中沉积反射层3时，使第一密闭空腔Q1侧壁的反射层3的高度低于第一密闭空腔Q1的高度，从而使第一密闭空腔Q1侧壁的反射层3顶部与红外吸收层12之间具有间隙。
步骤104：在真空环境下将键合衬底的底部与底部硅层键合，且在键合过程中，向第一密闭空腔和第二密闭空腔中填充红外敏感气体；
具体的，请参阅图18，可以采用常规的键合工艺使硅衬底1(键合衬底)的底部与底部硅层21相键合，对第一密闭空腔Q1和第二密闭空腔Q2中填充红外敏感气体的工艺，采用非真空键合工艺，在第一密闭空腔Q1和第二密闭空腔Q2内通入红外敏感气体；键合后，第一密闭空腔Q1和第二密闭空腔Q2内都填充有红外敏感气体，后续SOI硅片表面的第二开口打开，将第二密闭空腔里面的红外敏感气体抽真空去除。
步骤105：在键合衬底中刻蚀出第一开口，第一开口穿透键合衬底，且位于第一密闭空腔和第二密闭空腔之间的区域上方；
具体的，请参阅图19，可以采用光刻和等离子体干法刻蚀工艺在硅衬底1(键合衬底)中刻蚀出第一开口K1；第一开口K1穿透硅衬底1(键合衬底)，且位于第一密闭空腔Q1和第二密闭空腔Q2之间的区域上方
步骤106：将SOI衬底再反转过来，在顶部硅层中形成具有第一导电类型沟道的第一MOS器件和具有第二导电类型沟道的第二MOS器件；
具体的，请参阅图20，使SOI衬底2的顶部硅层23朝上，采用常规的CMOS工艺来制备第一MOS器件和第二MOS器件，这里不再赘述。从而在顶部硅层23中形成具有第一导电类型沟道C1的第一MOS器件和具有第二导电类型沟道C2的第二MOS器件；
步骤107：在顶部硅层和层间介质中且对应于第二密闭空腔上方刻蚀出第二开口，通过第二开口抽真空将第二密闭空腔中的红外敏感气体释放出来；
具体的，请参阅图21，可以采用光刻和刻蚀工艺来在顶部硅层23和层间介质22中且对应于第二密闭空腔Q2上方刻蚀出第二开口K2；
步骤108：在完成步骤107的SOI衬底上在真空环境下沉积金属前介质；金属前介质将第二开口顶部封住，从而第二密闭空腔中呈真空状态；
具体的，请参阅图22，这里，可以采用真空环境下的气相沉积法来沉积金属前介质6；通过调整工艺参数，使得金属前介质6将第二开口K2顶部封住，在第二开口K2中形成真空状态；金属前介质6填充第二开口K2的上部部分，或金属前介质6将第二开口K2填充满，但是金属前介质6不能填充于第二密闭空腔Q2中；
步骤109：在金属前介质上形成后道互连层，然后，在后道互连层、金属前介质、顶部硅层和层间介质中刻蚀出第三开口；第三开口对应于第一密闭空腔和第二密闭空腔之间的区域上方。
具体的，请参阅图23，后道互连层7的制备可以采用常规工艺，这里不再赘述；可以采用光刻和刻蚀工艺来在后道互连层7、金属前介质6、顶部硅层23和层间介质22中刻蚀出第三开口K3。第三开口K3对应于第一密闭空腔Q1和第二密闭空腔Q2之间的区域上方。
在本发明的另一个实施例中的红外探测器像元结构的制备方法，请参阅图24，具体包括：
步骤201：在键合衬底中依次形成红外吸收层和红外窗口层；且提供一SOI衬底；SOI衬底具有底部硅层、层间介质和顶部硅层；
具体的，关于此步骤201可以参考上述实施例中步骤101的描述，这里不再赘述。
步骤202：将SOI衬底倒置，在底部硅层中刻蚀出第一密闭空腔和第二密闭空腔；
具体的，关于此步骤202可以参考上述实施例中步骤102的描述，这里不再赘述。
步骤203：在第一密闭空腔中沉积反射层；然后，在第一密闭空腔中充入红外敏感气体；
具体的，可以采用常压气相沉积法在第一密闭空腔中沉积反射层，反射层可以为金属反射层。考虑到金属反射层具有对热量的快速传递效果，应当避免金属反射层与红外吸收层的直接接触，因此，在真空环境下在第一密闭空腔中沉积反射层时，使第一密闭空腔侧壁的反射层的高度低于第一密闭空腔的高度，从而使第一密闭空腔侧壁的反射层顶部与红外吸收层之间具有间隙。在第一密闭空腔中充入红外敏感气体的同时，可能不可避免会有一些红外敏感气体进入第二密闭空腔中；但是在后续第二开口形成后和沉积金属前介质时均在真空环境下，由于抽真空可以将第二密闭空腔内的一些红外敏感气体抽出，因此第二密闭空腔可以在后续形成真空状态；
步骤204：在常压下将键合衬底的底部与底部硅层键合；
具体的，键合时，第一密闭空腔和第二密闭空腔内都填充有红外敏感气体；
步骤205：在键合衬底中刻蚀出第一开口，第一开口穿透键合衬底，且位于第一密闭空腔和第二密闭空腔之间的区域上方；
步骤206：将SOI衬底再反转过来，在顶部硅层中形成具有第一导电类型沟道的第一MOS器件和具有第二导电类型沟道的第二MOS器件；
步骤207：在顶部硅层和层间介质中且对应于第二密闭空腔上方抽真空刻蚀出第二开口；
具体的，打开第二开口和后续沉积金属前介质层的工艺均为真空环境，因此，如果第二密闭空腔内存在红外敏感气体或其它气体均可以被抽出而形成真空。
步骤208：在完成步骤207的SOI衬底上在真空环境下沉积金属前介质；金属前介质将第二开口顶部封住，从而第二密闭空腔中形成真空状态；
步骤209：在金属前介质上形成后道互连层，然后，在后道互连层、金属前介质、顶部硅层和层间介质中刻蚀出第三开口；第三开口对应于第一密闭空腔和第二密闭空腔之间的区域上方。
具体的，关于此步骤205～209的具体描述可以参考上述一个实施例中的步骤105～109的描述，这里不再赘述。
虽然本发明已以较佳实施例揭示如上，然所述实施例仅为了便于说明而举例而已，并非用以限定本发明，本领域的技术人员在不脱离本发明精神和范围的前提下可作若干的更动与润饰，本发明所主张的保护范围应以权利要求书所述为准。

Claims (13)

  1. 一种红外探测器像元结构，其特征在于，包括键合衬底、键合于所述键合衬底上的硅衬底、以及位于硅衬底上的压电转换结构；其中，
    所述键合衬底中具有红外吸收层；红外吸收层用于吸收红外光；
    所述硅衬底中包括填充有红外敏感气体的密闭空腔区域；
    所述压电转换结构位于所述硅衬底的所述密闭空腔区域上方；其中，
    当红外光经过红外窗口层被选择性透过后，一部分红外光被红外吸收层吸收，一部分红外光透过红外吸收层进入密闭空腔，被密闭空腔内的红外敏感气体吸收掉，密闭空腔内的红外敏感气体吸收了红外光之后产生热量以及红外吸收层吸收了红外光之后产生热量传递给红外敏感气体，使得红外敏感气体产生膨胀并且作用于所述压电转换结构，所述压电转换结构形成的压电信号产生变化，从而实现对红外光的探测。
  2. 根据权利要求1所述的红外探测器像元结构，其特征在于，所述压电转换结构包括：底电极、顶电极以及位于顶电极和底电极之间的压电材料层；底电极键合于所述硅衬底和所述氧化层上；所述底电极与所述密闭空腔直接接触；当红外敏感气体产生膨胀并且作用于压电转换结构时，导致所述压电材料层形成的压电信号产生变化，通过所述顶电极和所述底电极将产生变化的压电信号传输到外部电路。
  3. 根据权利要求2所述的红外探测器像元结构，其特征在于，所述硅衬底的密闭空腔区域具有上梳齿状结构和下梳齿状结构，且所述上梳齿状结构的顶部与所述底电极相接触连接，所述底电极的下方连接有多个接触块，多个接触块的底部与所述上梳齿状结构的顶部相接触连接；上梳齿状结构的梳齿与下梳齿状结构的梳齿两两相间设置；上梳齿状结构的底部与所述红外吸收层之间具有空隙；所述下梳齿状结构的梳齿之间的空腔底部与所述红外吸 收层相接触连接；所述上梳齿状结构的和所述下梳齿状结构之间的空腔被所述底电极、所述氧化层、所述密闭空腔之外的所述硅衬底以及所述键合衬底密封，从而形成所述密闭空腔区域。
  4. 根据权利要求3所述的红外探测器像元结构，其特征在于，所述键合衬底中还具有互连电路，相邻的所述上梳齿状结构的梳齿和所述下梳齿状结构的梳齿及其之间的红外敏感气体构成竖直电容结构，所述下梳齿状结构的梳齿与所述互连电路相电连而构成所述竖直电容结构的下电极，所述压电转换结构的底电极作为所述竖直电容结构的上电极；当红外敏感气体产生膨胀时，红外敏感气体的压力作用于所述压电转换结构和所述竖直电容结构，导致所述竖直电容结构的电容信号产生变化以及导致所述压电材料层的压电信号产生变化，通过所述顶电极和所述底电极将产生变化的压电信号传输到外部电路，通过所述互连电路和所述底电极将产生变化的电容信号传输到外部电路，从而实现对红外光的探测。
  5. 根据权利要求3所述的红外探测器像元结构，其特征在于，所述红外窗口层具有多个沟槽，所述沟槽位于所述下梳齿状结构相邻的梳齿之间的下方以及所述密封空腔之外的所述硅衬底的下方，且不位于所述下梳齿状结构的梳齿的下方；所述红外吸收层填充与所述多个沟槽中。
  6. 根据权利要求3所述的红外探测器像元结构，其特征在于，所述压电转换结构的顶部还具有介质保护层，介质保护层覆盖于整个所述压电转换结构上。
  7. 根据权利要求3所述的红外探测器像元结构，其特征在于，在所述密闭空腔区域之外的所述硅衬底的边缘区域表面具有氧化层；所述压电转换结构中，所述压电材料层对应于所述上梳齿状结构上方且所述压电材料层的边缘区域不位于所述氧化层上方对应区域，所述底电极的边缘区域覆盖于所述氧化层上，所述顶电极的长度小于所述压电材料层的长度，从而使覆盖于整个所述压电转换结构上的所述介质保护层形成多级台阶状结构。
  8. 根据权利要求1所述的红外探测器像元结构，其特征在于，所述键合 衬底中还具有位于所述红外吸收层底部的红外窗口层，用于选择透过的红外光波段。
  9. 根据权利要求1所述的红外探测器像元结构，其特征在于，所述压电转换结构包括具有第一导电类型沟道的第一MOS器件和围绕所述第一MOS器件外围的具有第二导电类型沟道的第二MOS器件；第一导电类型与第二导电类型相反；第一导电类型沟道对应于所述密闭空腔上方中间区域，第二导电类型沟道横跨于所述密闭空腔侧壁上方的部分层间介质上且围绕所述第一导电类型沟道设置。
  10. 一种制备权利要求1所述的红外探测器像元结构的方法，其特征在于，包括：
    步骤01：提供键合衬底，在键合衬底中形成所述红外吸收层；
    步骤02：提供一硅衬底，在所述硅衬底中形成填充有红外敏感气体的密闭空腔区域，将硅衬底与所述键合衬底相键合；
    步骤03：将所述压电转换结构键合于所述硅衬底上，且所述压电转换结构与密闭空腔直接接触；其中，所述压电转换结构包括底电极、顶电极以及位于顶电极和底电极之间的压电材料层。
  11. 根据权利要求10所述的方法，其特征在于，所述步骤02具体包括：
    步骤021：在所述硅衬底顶部沉积氧化层；
    步骤022：在所述硅衬底中刻蚀出上梳齿状结构和下梳齿状结构，其中，上梳齿状结构的顶部和下梳齿状结构的顶部与所述氧化层相接触；所述上梳齿状结构的底部高于所述下梳齿状结构的底部；
    步骤023：将所述键合衬底与所述硅衬底的底部相键合；
    步骤024：在对应于所述上梳齿状结构的梳齿顶部的所述氧化层中刻蚀出凹槽；
    步骤025：在凹槽中填充导电材料，并且平坦化导电材料顶部与氧化层顶部齐平，以形成接触块；
    步骤026：将对应于所述密封空腔区域上方的所述氧化层去除，保留所述密闭空腔区域之外的所述硅衬底的边缘区域表面的所述氧化层。
  12. 根据权利要求11述的方法，其特征在于，所述步骤01具体包括：首先，在键合衬底中形成一红外窗口层；然后，在所述红外窗口层中在所述刻蚀出多个沟槽，沟槽位于下梳齿状结构相邻的梳齿之间区域的下方以及所述密封空腔之外的所述硅衬底的下方，且不位于所述下梳齿状结构的梳齿的下方；再在所述多个沟槽中沉积所述红外吸收层。
  13. 根据权利要求10所述的方法，其特征在于，所述步骤01具体包括：在所述键合衬底中依次形成红外吸收层和红外窗口层；且提供一SOI衬底；所述SOI衬底具有底部硅层、层间介质和顶部硅层；
    所述步骤02具体包括：
    步骤021’：将所述SOI衬底倒置，在真空环境下在所述底部硅层中形成所述第一空腔和所述第二空腔；
    步骤022’：在真空环境下在所述第一空腔中沉积所述反射层；
    步骤023’：在真空环境下将所述键合衬底的底部与所述底部硅层键合，且在键合过程中，向所述第一空腔和所述第二空腔中填充所述红外敏感气体；
    所述步骤03具体包括：
    步骤031’：在所述键合衬底中刻蚀出第一开口，第一开口穿透所述键合衬底，且位于所述第一空腔和所述第二空腔之间的区域上方；
    步骤032’：将所述SOI衬底再反转过来，在所述顶部硅层中形成所述具有第一导电类型沟道的第一MOS器件和所述具有第二导电类型沟道的第二MOS器件；
    步骤033’：在所述顶部硅层和所述层间介质中且对应于所述第二空腔上方刻蚀出第二开口，通过第二开口抽真空将第二空腔中的红外敏感气体释放出来；
    步骤034’：在完成所述步骤033’的SOI衬底上在真空环境下沉积金属前 介质；金属前介质将所述第二开口顶部封住，从而第二空腔中呈真空状态；
    步骤035’：在所述金属前介质上形成所述后道互连层，然后，在所述后道互连层、所述金属前介质、所述顶部硅层和所述层间介质中刻蚀出所述第三开口；所述第三开口对应于所述第一空腔和所述第二空腔之间的区域上方。
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