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    • 专利摘要:
    A method for manufacturing at least one microbolometer (10) comprising a vanadium oxide (VOx) sensitive material (15) containing nitrogen as an additional chemical element, the method comprising the steps of following: i.determination of a non-zero effective amount of the additional chemical element (N) from which the sensitive material (15), having undergone a step of exposure to a temperature Tr for a predetermined time Δtr, present an electrical resistivity ρa | r at ambient temperature, greater than or equal to 50% of the native value ρa of said sensitive material (15) at ambient temperature; ii. producing the sensitive material (15) in a thin layer having an amount of the additional chemical element (N) greater than or equal to the previously determined effective amount; iii. exposing the sensitive material (15) to a temperature of less than or equal to Tr for a time less than or equal to Δtr.
    公开号:FR3077878A1
    申请号:FR1800145
    申请日:2018-02-15
    公开日:2019-08-16
    发明作者:Denis Pelenc；Xavier Zucchi；Claire Vialle；Valerie Goudon；Abdelkader Aliane
    申请人:Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    METHOD FOR MANUFACTURING A MICROBOLOMETER WITH SENSITIVE MATERIAL BASED ON VANADIUM OXIDE
    TECHNICAL FIELD [ooi] The field of the invention is that of devices for detecting electromagnetic radiation, for example infrared or terahertz, comprising at least one resistive thermal detector comprising a sensitive material based on vanadium oxide. The invention is particularly applicable to the field of infrared imaging and thermography.
    This invention is the result of a contract awarded by the Ministry of Defense, which has certain rights over it.
    PRIOR ART [003] An electromagnetic radiation detection device can comprise a matrix of resistive thermal detectors, also called microbolometers, each microbolometer comprising an absorbing portion capable of absorbing the electromagnetic radiation to be detected.
    For the purpose of ensuring thermal insulation of the sensitive material of the microbolometers, the absorbent portions are usually in the form of membranes suspended above the substrate by anchoring pillars, and are thermally insulated from it. ci by holding arms and thermal insulation. These anchoring pillars and thermal insulation arms also have an electrical function by electrically connecting the suspended membranes to a reading circuit generally arranged in the substrate.
    The absorbent membrane comprises a sensitive material whose electrical resistivity p varies as a function of the temperature of the material. The sensitive material is characterized by the value p a of the electrical resistivity at ambient temperature as well as by its coefficient a (or TCR), which is defined by the relation a = 1 / p. dp / dT. The sensitive material can be a semiconductor material usually chosen from amorphous silicon and a vanadium oxide VOx.
    The choice of sensitive material depends in particular on its compatibility with the conventional deposition and etching steps usually used in microelectronics, and in particular in silicon technology. However, it appears that a sensitive material based on vanadium oxide is likely to have its electrical properties degraded as a result of the microbolometer manufacturing process.
    PRESENTATION OF THE INVENTION The object of the invention is to remedy at least in part the drawbacks of the prior art, and more particularly to propose a method for manufacturing at least one microbolometer comprising a sensitive material based on 'vanadium oxide whose electrical properties are preserved during the manufacturing process.
    For this, the object of the invention is a method of manufacturing at least one microbolometer comprising a sensitive material based on vanadium oxide containing at least nitrogen as an additional chemical element, the method comprising the following steps:
    i. determination of a so-called non-zero effective quantity of the additional chemical element from which the sensitive material, having undergone a step of exposure to a temperature T r for a predetermined duration Atr, exhibits an electrical resistivity p a | r to ambient temperature, greater than or equal to 50% of the native value p a of said material sensitive to ambient temperature;
    ii. production of the sensitive material in a thin layer having an amount of the additional chemical element greater than or equal to the effective amount previously determined;
    iii. exposure of the sensitive material to a temperature greater than ambient temperature and less than or equal to T r for a duration less than or equal Atr.
    Some preferred, but not limiting, aspects of this manufacturing process are as follows.
    The manufacturing process may include a prior step of determining the native value p a of the electrical resistivity at room temperature of the sensitive material containing the non-zero quantity considered of the additional chemical element.
    [ooii] Step iii of exposure of the sensitive material may include a step of depositing a protective layer covering the sensitive material.
    Step iii of exposure of the sensitive material may include a step of depositing an encapsulation layer transparent to the electromagnetic radiation to be detected intended to define a cavity in which the microbolometer is located.
    The temperature T r can be greater than or equal to 28o ° C.
    The duration At r can be greater than or equal to 90 min.
    During step iii), the exposure step can be carried out at the temperature T r for the duration Δΐ Γ .
    The invention also relates to a microbolometer comprising a sensitive material based on vanadium oxide, said sensitive material containing at least nitrogen as an additional chemical element, the amount of which is greater than or equal to a so-called effective amount. giving the sensitive material an even value of electrical resistivity at room temperature, after exposure to a temperature of 28 ° C. for 90 min, at least equal to 50% of the native value p a of said material sensitive at room temperature.
    The sensitive material may include an amount of nitrogen, defined as the ratio of the number of nitrogen atoms to that of vanadium, at least equal to 0.091.
    The invention also relates to a device for detecting electromagnetic radiation, comprising a matrix of microbolometers according to any one of the preceding characteristics.
    Each microbolometer can be placed in a separate hermetic cavity delimited by an encapsulation structure transparent to the electromagnetic radiation to be detected, the encapsulation structure comprising at least one layer made of amorphous silicon.
    Each sensitive material can be covered by a protective layer of silicon nitride.
    BRIEF DESCRIPTION OF THE DRAWINGS Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of nonlimiting example, and made with reference to the accompanying drawings in which:
    Figures 1A and 1B are schematic and partial views, respectively in perspective and in section along the plane A-A, of a microbolometer according to one embodiment, comprising a sensitive material based on vanadium oxide;
    FIG. 2 is a graph illustrating the evolution of the electrical resistivity p a | r at room temperature of the sensitive material based on vanadium oxide, after exposure of said material to a temperature T r for a period Atr, in the case where the sensitive material may or may not have a sufficient amount of nitrogen.
    DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS In the figures and in the following description, the same references represent the same or similar elements. In addition, the different elements are not shown to scale so as to favor the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and can be combined with one another. Unless otherwise indicated, the terms "substantially", "approximately", "in the order of" mean to within io%.
    The indications relating to the chemical composition of a compound are expressed by its crude chemical formula, conventionally expressed with respect to one (1) vanadium atom. Thus, for a compound VOxBy, mentioned here purely by way of illustration, the value x of the quantity of oxygen is the number of oxygen atoms for i atom of vanadium, and the value y of the quantity of boron is the number of boron atoms for i vanadium atom. The value of the quantity of the chemical element is given to io%. Furthermore, the atomic proportion of each chemical element in the compound VOxBy is i / (i + x + y) for vanadium, x / (ι + χ + y) for oxygen, and y / (ι + χ + y) for boron.
    The invention relates in particular to a method of manufacturing at least one resistive thermal detector, also called a microbolometer, comprising a sensitive material based on VOx vanadium oxide. The microbolometer can be adapted to detect infrared or terahertz radiation. The sensitive material comprises a sufficient non-zero quantity of at least one additional chemical element, here nitrogen and possibly, in addition to nitrogen, boron B and / or carbon C. In addition, the manufacturing process implements at least one step in which the sensitive material is exposed to a temperature greater than ambient temperature and less than or equal to the temperature T r , for a duration less than or equal to At r , for example at 300 ° C. during isom , 30min, even 90min or more. The temperature T r of thermal exposure is therefore higher than the ambient temperature.
    This thermal exposure step may correspond to the deposition at around 300 ° C. of a protective layer, for example made of a silicon nitride SiN or a silicon oxide SiO, covering the sensitive material for the purpose of protect it from any subsequent contamination by possible chemical elements. It can also correspond to the production of an encapsulation layer of amorphous silicon, said layer being intended to define a hermetic cavity in which the microbolometer is located. It can also be an activation at approximately 300 ° C. of a getter material located in the hermetic cavity, this getter material being intended to react with residual gas possibly present in the cavity to maintain the latter at a level sufficient vacuum.
    These examples are given by way of illustration. The step of thermal exposure to the temperature T r during the period Atr can be implemented, in general, within the framework of technological steps for manufacturing the microbolometer carried out after the production of the sensitive material, or even in the framework of technological stages in the manufacture of the detection device after the production of the microbolometers, in particular for the integration of additional functionalities at the level of the detection chip.
    Figures 1A and 1B are schematic and partial views, respectively in perspective and in section along the plane AA, of a microbolometer 10 of a device 1 for detecting electromagnetic radiation, the microbolometer comprising a sensitive material 15 based on VOx vanadium oxide.
    The microbolometer 10 includes an absorbent membrane 11 of sensitive material 15 based on VOx vanadium oxide, suspended above a substrate 2 by anchoring pillars 12 and thermal insulation arms 13, as well an electronic control and reading circuit (not shown) located in the substrate 2. The microbolometer 10 is here adapted to absorb infrared radiation included in the long infrared wavelength band (called LWIR), ranging from 8 pm at around 4pm.
    We define here and for the following description a direct three-dimensional orthogonal coordinate system (Χ, Υ, Ζ), where the XY plane is substantially parallel to the plane of a substrate 2, the Z axis being oriented in a direction substantially orthogonal to the plane of the substrate 2. Furthermore, the terms “lower” and “upper” are understood to be relative to an increasing positioning when one moves away from the substrate 2 in the direction + Z.
    The microbolometer 10 comprises a substrate 2, produced in this example based on silicon, comprising an electronic circuit (not shown) allowing the control and the reading of the microbolometer. The electronic circuit includes portions of conductive lines, for example metallic, separated from each other by a dielectric material, for example a mineral material based on silicon such as a silicon oxide SiO, a silicon nitride SiN, or their alloys.
    for this purpose may include active electronic elements, for example diodes, transistors, capacitors, resistors, etc., connected by electrical interconnections to the microbolometer 10 on the one hand, and to an interconnection pad (not shown) of on the other hand, the latter being intended to electrically connect the detection device 1 to an external electronic device.
    The upper face of the substrate 2 can be coated with a protective layer (not shown) especially when the absorbent membrane is produced on an inorganic sacrificial layer, which is then removed by chemical attack in an acid medium. It can cover or be covered by a reflective layer 14 placed under the absorbent membrane 11. When it covers the reflective layer 14, it is made of a material at least partially transparent to the electromagnetic radiation to be detected. The protective layer has an etching stop function, and is suitable for ensuring protection of the substrate and the inter-metal dielectric layers when they are made of a mineral material against chemical attack, by example a chemical attack in HF acid medium (hydrofluoric acid) implemented subsequently to etch the mineral sacrificial layer used during the production of the absorbent membrane. This protective layer thus forms a hermetic and chemically inert layer. It is electrically insulating to avoid any short circuit between the metal line portions. It can thus be made of Al2O3 alumina, or even of aluminum nitride or fluoride. It may have a thickness of between a few tens and a few hundred nanometers, for example between ηm and 5 μm, preferably between ηm and 30 nm.
    The microbolometer 10 includes an absorbent membrane 11 incorporating a sensitive material 15 based on vanx oxide VOx, suspended above the substrate 2 by anchoring pillars 12 and thermal insulation arms 13. The pillars anchor 12 are electrically conductive, and locally pass through the protective layer to ensure electrical contact with the electronic circuit. The absorbent membrane 11 is spaced from the substrate 2, and in particular from the reflective layer 14, by a non-zero distance. This distance is preferably adjusted so as to form a quarter-wave cavity optimizing the absorption of the electromagnetic radiation to be detected by the suspended membrane 11.
    As illustrated in fig.iB, the absorbent membrane 11 may include a lower support layer 20 made of an electrically insulating material on which rest two electrodes 21.1, 21.2 distinct from each other, made for example TiN which has a strong absorption of infrared radiation. A thin layer of sensitive material 15 rests on the support layer 20 and comes into contact with each of the two electrodes 21.1, 21.2. The sensitive material 15 is here covered with a protective layer 22, made for example of a silicon nitride SiN or a silicon oxide SiO, which makes it possible to avoid any subsequent contamination of the sensitive material 15. This example is given by way of purely illustrative and other arrangements of the electrodes and of the sensitive material are possible.
    Furthermore, the microbolometer 10 can be located in an airtight cavity defined by an encapsulation structure (not shown), as described in particular in the publication by Dumont et al. titled Current progress on pixel level packaging for uncooled IRFPA, SPIE Proceedings Vol. 8353 (2012). The encapsulation structure can be formed by a stack of different thin layers, such as an encapsulation layer for example made of amorphous silicon deposited by CVD or iPVD, covered with a sealing and anti-reflective layer, by example produced in different sublayers of germanium and zinc sulfide, deposited for example by EBPVD, IBS or other. Such an encapsulation structure is described in particular in patent application EP3067675.
    The sensitive material 15 is based on VOx vanadium oxide, that is to say it is a VOx vanadium oxide compound containing at least nitrogen N as an additional chemical element, and optionally, in addition to nitrogen, boron B and / or carbon C. An additional chemical element is a chemical element added voluntarily to the basic compound that is vanadium oxide. The basic compound can be chosen from V0 2 , V2O5, V3O5, or even can have another value of the stoichiometric ratio of the number of oxygen atoms to the number of vanadium atoms. As previously specified, the compound of raw chemical formula V2O5 here has 5 oxygen atoms for 2 vanadium atoms, and the compound V3O5 has 5 oxygen atoms for 3 vanadium atoms. The sensitive material 15 then corresponds to a modified compound, that is to say it corresponds to the basic compound which has been modified by the addition of at least one additional chemical element, here nitrogen N and optionally, in addition to nitrogen, boron B and / or carbon C. The sensitive material 15 can be an amorphous material, or be a crystalline material having one or more crystalline phases. It can also be in the form of a mixture of an amorphous phase and one or more crystalline phases.
    The amount of additional chemical element, namely the number of nitrogen atoms and optionally, in addition to nitrogen, boron and / or carbon over that of vanadium, is chosen so as to give the sensitive material, which has been exposed to the temperature Tr for the duration Δΐ Γ , an electrical resistivity p a | r at ambient temperature at least equal to 50% of its native value p a . By at least equal, we mean greater or equal. The native value p a of the electrical resistivity is that of the sensitive material before it has been exposed to the temperature Tr during Atr.
    The sensitive material has an electrical resistivity at room temperature preferably between 1 and 2θΩ.αη approximately, or even less.
    The amount of nitrogen and possibly boron and / or carbon is then greater than or equal to a so-called effective value, or effective amount. The effective quantity is the minimum, non-zero quantity of nitrogen and possibly boron and / or carbon from which the sensitive material, having undergone a stage of exposure to the temperature Tr during the period Atr, exhibits a resistivity electric p a | r at room temperature, at least equal to 50% of the native value p a of said material sensitive at room temperature. The ambient temperature can be equal to 30 ° C. The temperature T r is greater than room temperature, and is preferably greater than or equal to 280 ° C., and preferably greater than or equal to 300 ° C. It can be less than or equal to 4OO ° C. The duration Atr is preferably greater than or equal to a few minutes or tens of minutes, or even a few hours.
    In other words, when the sensitive material, the amount of nitrogen and possibly boron and / or carbon is greater than or equal to the effective amount, has not been exposed to the temperature T r during the period Atr , its electrical resistivity at room temperature has the native value p a . After thermal exposure to T r during Atr, the sensitive material then has an electrical resistivity p a | r at room temperature at least equal to 50% of the native value p a .
    The effective amount depends in particular on the base compound considered, as well as on the chosen values of the temperature T r and the duration Atr of the thermal exposure. A person skilled in the art is able to determine the effective amount, that is to say the minimum amount of nitrogen and possibly boron and / or carbon, to be added to the base compound so that the sensitive material has an electrical resistance. p a | r at room temperature at least equal to 50% of the native value p a . The effective quantity can be chosen, if necessary, so that the value p a | r is greater than 50%, for example at least equal to 75%, or even at least equal to 90% of the native value p a .
    The electrical resistivity at room temperature of the sensitive material can be determined by a conventional four-point measurement technique, and the atomic composition of the sensitive material, and therefore the amount of the additional chemical element, can in particular be determined by NRA {Nuclear Reaction
    Analysis), by RBS (Rutherford Backscattering Spectroscopy), by SIMS (Secondary Ion Mass Spectrometry), by XPS (X-ray Photoelectron Spectroscopy), using suitable standards.
    It is known that the electrical resistivity at room temperature of a sensitive material consisting of VOx vanadium oxide can drop in value when it has been exposed to a temperature of 3OO ° C or 4OO ° C , in particular under an inert atmosphere (under nitrogen), as described in the publication by Venkatasubramanian et al. titled Correlation of temperature response and structure of annealed VOx thin films for IR detector applications, J. Vac. Sci. Technol. A 27 (4), 2009, 956-961. Thus, a sensitive material consisting of vanadium oxide, therefore without additional chemical element such as nitrogen, boron and carbon, has an electrical resistivity p a | r at room temperature of the same order of magnitude as its native value p a after exposure to a temperature of the order of 200 ° C. under an inert atmosphere. However, the electrical resistivity p | r falling an order of magnitude or even more orders of magnitude when the sensitive material was exposed to a temperature of 3OO ° C or 4OO ° C for 10min or 30min under an inert atmosphere .
    However, the inventors have found that the addition of a sufficient amount of nitrogen in a sensitive material based on vanadium oxide, and possibly, in addition to nitrogen, boron and / or carbon surprisingly improves the thermal stability of the sensitive material during thermal exposure to high temperatures, for example of the order of 300 ° C. or even more, for several tens of minutes.
    The sensitive material based on vanadium oxide, with the addition of a sufficient amount of nitrogen, and optionally boron and / or carbon, then has an electrical resistivity p a | r at room temperature at least equal. at 50% of the native value p a . The sufficient amount is an amount greater than or equal to the determined effective amount. Such a sensitive material then does not exhibit significant degradation of its electrical properties, and in particular of degradation of its electrical resistivity at ambient temperature, following the process for manufacturing the microbolometer which comprises at least one step of exposing the sensitive material to Tr during Atr, like steps of depositing thin layers, encapsulating the microbolometer in an airtight cavity, or even activating a getter material.
    Such a sensitive material is therefore particularly advantageous in the context of a collective manufacturing process of a matrix of microbolometers of a device for detecting electromagnetic radiation. In fact, during a thermal exposure step, the temperature field can exhibit spatial inhomogeneities within a thin film deposition reactor or an annealing furnace, which can result in a dispersion of the electrical properties of microbolometers. Thus, by using the sensitive material with a sufficient amount of nitrogen and possibly boron and / or carbon, the microbolometers exhibit better thermal stability during thermal exposure to the temperature Tr, thus reducing the dispersion of the electrical properties. microbolometers.
    Furthermore, the sensitive material may also comprise a transition metal belonging to period 4 of the periodic table of the elements, that is to say scandium Sc, titanium Ti, chromium Cr, manganese Mn, iron Fe, cobalt Co, nickel Ni, copper Cu and / or zinc Zn.
    FIG. 2 illustrates an example of evolution of the electrical resistivity p a | r at room temperature of the sensitive material as a function of the temperature T r of thermal exposure, for a sufficient amount of added nitrogen. This example thus highlights the increase in the range of thermal stability that the sensitive material exhibits when it contains a sufficient amount of nitrogen, that is to say an amount greater than or equal to the effective amount.
    Here, the sample of the VOx sensitive material is obtained by ion beam spraying (IBS, for Ion Beam Sputtering, in English), for example by spraying a target of vanadium under an oxidizing atmosphere at a partial pressure of oxygen for example of the order of 10-4 Torr approximately. The sample of the sensitive material VOxNw was obtained by IBS spraying in an atmosphere comprising nitrogen in addition to oxygen.
    The curve C1 is identical to that described above. The curve C2 illustrates the evolution of the electrical resistivity p a | r as a function of the temperature T r for a sensitive material of type VOxNw, where the quantity w of nitrogen, that is to say the ratio of the number d nitrogen atoms on that of vanadium, is here equal to 0.091. It appears that the threshold value Tth of the sensitive material, at which the electrical resistivity p a | r is at least equal to 50% of the native value p a , also increases as the quantity w of nitrogen in the material increases sensitive. Thus, it goes from 257 ° C for VOx without addition of nitrogen to approximately 31o ° C for VOxNo.ogi.
    Thus, the effective amount of nitrogen so that the sensitive material has at least 50% of its native value after having been exposed to 3io ° C for 90 min is here substantially equal to 0.091. Also, a sensitive material based on vanadium oxide comprising an amount w of nitrogen equal to at least 0.091 has a significant thermal stability allowing it to be exposed to temperatures up to 3io ° C. for at most 90 min, while having its electrical properties preserved.
    The value of the effective amount of nitrogen depends on the exposure temperature T r and the duration of exposure Atr. Those skilled in the art are then able to determine the value of the effective amount of nitrogen to be added to the base compound VOx as a function of the thermal characteristics T r and Atr of the exposure step.
    The sensitive material may include, in addition to nitrogen, an amount of boron and / or carbon. The amount of additional chemical elements, i.e. the amount of nitrogen and that of boron and / or carbon, is determined so that the sensitive material 15 has an electrical resistivity p a | r at room temperature at least equal to 50% of the native value p a .
    A sensitive VOxNwBy material containing, in addition to nitrogen, a quantity of boron can be produced by implanting boron in a VOxNw material produced beforehand by IBS spraying in an oxidizing atmosphere containing nitrogen. It is the same in the case of an addition of carbon in the compound VOxNw. Other techniques for producing the sensitive material VOxNw with the addition of boron and / or carbon can be used.
    It appears that the sensitive material based on VOxNw with a sufficient amount of nitrogen and possibly boron and / or carbon has a relative variation in the electrical resistivity p a | r as a function of the temperature Tr particularly low when the thermal exposure temperature is less than or equal to its threshold value Tth. This then makes it possible to limit the dispersion of electrical properties of the microbolometers resulting from possible spatial inhomogeneities of the temperature field within the deposition reactor or the annealing furnace.
    Thus, one aspect of the invention relates to a method of manufacturing at least one microbolometer îo, and advantageously, to a method of collective production of a matrix of bolometers îo of a detection device 1 .
    The manufacturing process comprises at least one step during which the sensitive material 15 of the microbolometers 10 is subjected to a temperature T r for the duration At r .
    The manufacturing process then includes a prior step of determining the effective value of the amount of at least one additional chemical element, namely nitrogen and possibly, in addition to nitrogen, boron and / or of carbon, from which the sensitive material 15, having undergone exposure to the temperature T r during the period At r , has an electrical resistivity p a | r at room temperature, at least equal to 50% of its native value p a .
    In a step of producing the absorbent membrane, the sensitive material 15 is deposited in a thin layer on the support layer 20, which rests on a sacrificial layer. It contains a sufficient amount of nitrogen, and possibly of boron and / or carbon, that is to say an amount greater than or equal to the determined effective value. It may have a thickness of the order of a few tens to a few hundred nanometers, for example comprised between ison and soonm, for example equal to 8onm.
    The sensitive material 15 can be obtained by IBS spraying under an atmosphere containing nitrogen, and optionally by ion implantation of boron and / or carbon. The atmosphere is oxidizing during the production of the thin layer of VO X and the partial pressure of oxygen can be of the order of approximately 1 5 to 10 4 Torr approximately, for example equal to 6.10-5 Torr, depending on the desired native value of the electrical resistivity of the sensitive material. The value of the partial pressure of oxygen as well as the nitrogen content in the atmosphere, even the boron and / or carbon content, can be obtained from calibration curves previously obtained. Other production techniques can be used, such as the Atomic Layer Deposition (ALD), or the deposition of the sensitive material by cathode sputtering in reactive mode with a metal or vanadium oxide target, possibly followed by implantation of boron and / or carbon.
    It is then possible to cover the VOxNw compound with the protective layer of silicon nitride, with a thickness for example of μm deposited by PECVD. The optional addition of boron and / or carbon can then be carried out by carrying out several successive implantations. Thus, for a thin layer of the VOxNw compound 8 μm thick covered with the SiN protective layer of 3 μm thick, three successive boron implantations can be carried out, starting from doses of the order of io 16 at / cm 2 and for implantation energies of the order of ten to a few tens of KeV. Other techniques for producing the sensitive material can be used, or even other variants of the deposition techniques mentioned above. Thus, for the addition of carbon, it is possible to spray a target containing only vanadium, in an oxidizing atmosphere containing nitrogen and CO or CO 2 .
    The manufacturing process then comprises at least one step to which the sensitive material is exposed to a temperature above room temperature, and less than or equal to T r for a duration less than or equal to Atr. The exposure temperature can be equal to T r and be between 3OO ° C and 4OO ° C, and the duration can be equal to Atr and be of the order of a few minutes to a few hours. This thermal exposure step can be carried out under an inert atmosphere or under vacuum.
    It may thus be the deposition of the thin protective layer 22 of silicon nitride by PECVD, the deposition of at least one of the thin layers forming the encapsulation structure which defines the hermetic cavity, l elimination of the sacrificial layer or sacrificial layers used to produce the suspended membrane or the encapsulation structure, or even the activation of a getter material placed in said hermetic cavity.
    Specific embodiments have just been described. Different variants and modifications will appear to those skilled in the art.
    权利要求:
    Claims (11)
    [1" id="c-fr-0001]
    1. Method for manufacturing at least one microbolometer (îo) comprising a sensitive material (15) based on vanadium oxide (VOx) containing at least nitrogen as an additional chemical element, the method comprising the following steps:
    i. determination of a so-called non-zero effective quantity of the additional chemical element (N) from which the sensitive material (15), having undergone a step of exposure to a temperature Tr for a predetermined duration Atr, exhibits an electrical resistivity p a | r at room temperature, greater than or equal to 50% of the native value p a of said sensitive material (15) at room temperature;
    ii. production of the sensitive material (15) in a thin layer having an amount of the additional chemical element (N) greater than or equal to the effective amount previously determined;
    iii. exposure of the sensitive material (15) to a temperature greater than ambient temperature and less than or equal to Tr for a duration less than or equal Atr.
    [2" id="c-fr-0002]
    2. The manufacturing method according to claim 1, wherein step iii of exposure of the sensitive material (15) comprises a step of depositing a protective layer (22) covering the sensitive material.
    [3" id="c-fr-0003]
    3. The manufacturing method according to claim 1 or 2, wherein step iii of exposure of the sensitive material (15) comprises a step of depositing an encapsulation layer transparent to the electromagnetic radiation to be detected intended to define a cavity. in which the microbolometer is located.
    [4" id="c-fr-0004]
    4. The manufacturing method according to any one of claims 1 to 3, wherein the temperature Tr is greater than or equal to 28o ° C.
    [5" id="c-fr-0005]
    5. The manufacturing method according to any one of claims 1 to 4, wherein the duration Atr is greater than or equal to 90 min.
    [6" id="c-fr-0006]
    6. The manufacturing method according to any one of claims 1 to 5, wherein, during step iii), the exposure step is carried out at the temperature T r for the duration Atr.
    [7" id="c-fr-0007]
    7. Microbolometer (10) comprising a sensitive material (15) based on vanadium oxide (VOx), said sensitive material (15) containing at least nitrogen (N) as an additional chemical element, the quantity of which is greater or equal to a quantity known as effective conferring on the sensitive material (15) a value p a | r of electrical resistivity at room temperature, after exposure to a temperature of 28 ° C. for 90 min, at least equal to 50% of the native value p a of said sensitive material (15) at room temperature.
    [8" id="c-fr-0008]
    8. Microbolometer (10) according to claim 7, wherein the sensitive material (15) comprises an amount of nitrogen, defined as the ratio of the number of nitrogen atoms to that of vanadium, at least equal to 0.091.
    [9" id="c-fr-0009]
    9. Device for detecting (1) electromagnetic radiation, comprising a matrix of microbolometers according to claim 7 or 8.
    [10" id="c-fr-0010]
    10. Detection device (1) according to claim 9, each microbolometer (10) being disposed in a separate hermetic cavity delimited by an encapsulation structure transparent to the electromagnetic radiation to be detected, the encapsulation structure comprising at least one layer produced made of amorphous silicon.
    [11" id="c-fr-0011]
    11. Detection device (1) according to claim 9 or 10, each sensitive material (15) being covered by a protective layer (22) made of silicon nitride.
    1/2
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    同族专利:
    公开号 | 公开日
    FR3077878B1|2022-02-04|
    US20210010868A1|2021-01-14|
    CA3089599A1|2019-08-22|
    CN111684245A|2020-09-18|
    WO2019158863A1|2019-08-22|
    KR20200118853A|2020-10-16|
    US11181424B2|2021-11-23|
    EP3752804A1|2020-12-23|
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    法律状态:
    2019-02-28| PLFP| Fee payment|Year of fee payment: 2 |
    2019-08-16| PLSC| Publication of the preliminary search report|Effective date: 20190816 |
    2020-02-28| PLFP| Fee payment|Year of fee payment: 3 |
    2020-11-06| CL| Concession to grant licences|Name of requester: L'ETAT FRANCAIS, MINISTERE DE LA DEFENSE, FR Effective date: 20200928 |
    2021-02-26| PLFP| Fee payment|Year of fee payment: 4 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1800145|2018-02-15|
    FR1800145A|FR3077878B1|2018-02-15|2018-02-15|METHOD FOR MANUFACTURING A SENSITIVE MATERIAL MICROBOLOMETER BASED ON VANADIUM OXIDE|FR1800145A| FR3077878B1|2018-02-15|2018-02-15|METHOD FOR MANUFACTURING A SENSITIVE MATERIAL MICROBOLOMETER BASED ON VANADIUM OXIDE|
    US16/969,453| US11181424B2|2018-02-15|2019-02-14|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
    EP19710453.2A| EP3752804A1|2018-02-15|2019-02-14|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
    CA3089599A| CA3089599A1|2018-02-15|2019-02-14|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
    KR1020207026117A| KR20200118853A|2018-02-15|2019-02-14|Method for manufacturing a microborometer comprising a vanadium oxide-based sensitive material|
    PCT/FR2019/050326| WO2019158863A1|2018-02-15|2019-02-14|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
    CN201980012310.6A| CN111684245A|2018-02-15|2019-02-14|Method for manufacturing a microbolometer with a sensitive material based on vanadium oxide|
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