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    • 专利摘要:
    The invention relates to a method for manufacturing a microbolometer (10) comprising a sensitive material (15) based on vanadium oxide (VOx) comprising an additional chemical element selected from boron (B), carbon (C ), with the exception of nitrogen (N), comprising the following steps: i.determination of a non-zero effective amount of the additional chemical element (B, C) from which the sensitive material (15) , having undergone exposure at a temperature Tr for a predetermined time Δtr, exhibits an even electric resistivity at ambient temperature, greater than or equal to 50% of the native value ρa of said sensitive material (15); ii. producing the thin-film sensitive material (15) having an amount of the additional chemical element (B, C) 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:FR3077879A1
    申请号:FR1800141
    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 CEA；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.
    STATE OF THE PRIOR ART 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.
    In order to provide 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 isolated 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 = ι / 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 invention aims to at least partially remedy 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 comprising at least one additional chemical element chosen from boron, carbon, with the exception of nitrogen, comprising the following stages:
    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 Tr for a predetermined duration Atr, exhibits an electrical resistivity p a | r at temperature ambient, greater than or equal to 50% of the native value pa 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 above ambient temperature and less than or equal to Tr 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.
    [ooio] Step iii of exposure of the sensitive material may include a step of depositing a protective layer covering the sensitive material.
    [ooii] 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.
    [ooi2] The temperature Tr can be greater than or equal to 28o ° C.
    The duration Atr can be greater than or equal to 90 min.
    During step iii), the exposure step can be carried out at temperature T r for the duration Atr.
    The invention also relates to a microbolometer comprising a sensitive material based on vanadium oxide, said sensitive material comprising at least one additional chemical element chosen from boron and carbon, with the exception of nitrogen, the quantity of which is greater than or equal to a so-called effective quantity giving the sensitive material 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 value native p a of said material sensitive to ambient temperature.
    The sensitive material can comprise an amount of boron, defined as the ratio of the number of boron atoms to that of vanadium, at least equal to 0.097.
    The sensitive material may contain an amount of carbon, defined as the ratio of the number of carbon atoms to that of vanadium, at least equal to 0.063.
    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;
    FIGS. 2A and 2B are graphs 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, for different quantities of an additional chemical element, the latter being boron (fig.2A), carbon (fig.2B).
    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 1 atom of vanadium, and the value y of the quantity of boron is the number of boron atoms for 1 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 / (i + x + y) for oxygen, and y / (i + x + y) for boron.
    The invention relates in particular to a process for 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 chosen from boron B, carbon C, with the exception of nitrogen N. 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 Tr, for a duration less than or equal to Atr, for example at 300 ° C. for an hour, 30 min, or even 90 min or more. The temperature of thermal exposure Tr is therefore higher than 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 Tr for the duration 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 context technological stages in the manufacture of the detection device after the production of the microbolometer (s), 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 îo 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 that 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 μιη 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 lonm and 5oonm, preferably between îonm and 3onm.
    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 that it is a VOx vanadium oxide compound comprising at least one additional chemical element chosen from boron B, carbon C, with the exception of nitrogen N. The sensitive material 15 therefore does not contain nitrogen: the amount of nitrogen in the sensitive material 15 is therefore zero or almost zero, that is to say is less than or equal to 0.1% in atomic proportion. The additional chemical element B, C is defined as a chemical element voluntarily added 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 chemical element chosen from boron B and carbon C. sensitive material may 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 B, C, namely the number of boron and / or carbon atoms on that of vanadium, is chosen so as to give the sensitive material, which has been exposed to temperature T r during the period At r , an electrical resistivity p a | r at room 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 additional chemical element B, C is then greater than or equal to a value called effective, or effective amount. The effective quantity is the minimum quantity, not zero, of the additional chemical element B, C from which the sensitive material, having undergone a stage of exposure to the temperature Tr during the period At r , has an electrical resistivity 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 Tr is greater than the ambient 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 boron and / or carbon of which is greater than or equal to the effective amount, has not been exposed to the temperature Tr during the period Atr, its electrical resistivity at temperature ambient has the native value p a . After thermal exposure to Tr 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 Tr and the duration Atr of the thermal exposure. Those skilled in the art are able to determine the effective amount, that is to say the minimum amount of 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 vanadium oxide VOx can drop in value when it has been exposed to a temperature of 30 ° 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 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 ° C or 3oo 4oo ° C for 10min or 30min under an inert atmosphere .
    However, the inventors have found that the addition, in a sensitive material based on vanadium oxide, of a sufficient amount of at least one additional chemical element chosen from boron and carbon, makes it possible to surprisingly, improve 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 sufficient addition of one or more of the additional chemical elements mentioned above, then has an electrical resistivity p a | r at room temperature at least equal to 50% of the native value p a . The sufficient amount of boron and / or carbon 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 room temperature, at the continuation of the microbolometer manufacturing process which comprises at least one step of exposing the material sensitive to Tr during Atr, such as steps of depositing thin layers, encapsulating the microbolometer in a hermetic cavity, or even activating a getter material.
    Such a sensitive material is then 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 boron and / or carbon, the microbolometers exhibit better thermal stability during thermal exposure to the temperature T r , thus reducing the dispersion of the electrical properties of the 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. 2A illustrates examples of changes in 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 different quantities of boron added. These examples thus demonstrate the increase in the range of thermal stability that the sensitive material exhibits when it contains a sufficient amount of boron.
    In these examples, the sample of sensitive material VOx was produced by an ion beam spraying deposition technique (IBS, for Ion Beam Sputtering in English), for example by spraying a target of vanadium under atmosphere oxidizing at a partial pressure of oxygen, for example of the order of approximately 10'4 Torr. The samples of sensitive material VO x B y were obtained by implantation of boron in a VOx material produced beforehand by IBS spraying. Other techniques for producing the sensitive material VOxBy can be used. Electrical resistivity p a | r of the sensitive material is measured at ambient temperature, here at 30 ° C., after exposure of the sensitive material for 90 min to a temperature Tr of between 230 ° C. and 390 ° C.
    Thus, the curve Cl illustrates the evolution of the electrical resistivity p a | r as a function of the temperature T r for a sensitive material consisting of vanadium oxide VOx not containing any additional chemical element B, C. In this example, the value x of the quantity of oxygen, namely the ratio of the number of oxygen atoms to that of vanadium, is equal to 1.94. The curve Ci shows that the electrical resistivity p a | r of VOx without added boron presents a transition at a temperature Tthi, here of the order of 250 ° C.: in fact, up to the threshold value Tthi, the electrical resistivity p a | r is substantially constant and is at least equal to 50% of the native value p a , here of the order of 23O.cm. Then, beyond the threshold value Tthi, the electrical resistivity p a | r decreases sharply as the temperature T r increases. It thus loses about three orders of magnitude after the VOx material has been exposed to 3io ° C for 90 min.
    Curves C2 to C5 illustrate the evolution of the electrical resistivity p a | r as a function of the temperature ΊΪ for a sensitive material of the VOxBy type, where the quantity y of boron, namely the ratio of the number of boron atoms to that of vanadium, is here equal to 0.012 (C2), 0.024 (C3 ), 0.048 (C4), and 0.097 (C5), which corresponds respectively to an atomic proportion of boron equal to 0.4% (C2), 0.8% (C3), 1.6% (C4) and 3 , 2% (C5). The quantity x of oxygen remains identical to that of the curve Cl. It appears that the threshold temperature Tth, at which the electrical resistivity p a | r is at least equal to 50% of the native value p a , increases as 'increases the amount y of boron in the sensitive material. Thus, it goes from 275 ° C for VOxB 0.012 and 277 ° C for VOxBo.024, to 29O ° C for VOxBo.048, and is higher than 37O ° C for VOxBo.097.
    The table below brings together the threshold values Tth of thermal exposure temperature as a function of the different values y of the amount of boron in the sensitive material:
    Quantity y of boron added Threshold temperature Tth C5: VOxBy with y = o, 097 > 37O ° C C4: VOxBy with y = o, 048 29o C. C3: VOxBy with y = o, 024 277 ° C C2: VOxBy with y = 0, 012 275 ° C Cl: VOx with x = i, 94; y = 257 ° C
    Thus, the effective amount of boron 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 greater than 0.048 and less than 0.097. Also, it is particularly advantageous that the sensitive material based on vanadium oxide comprises a quantity y of boron at least equal to 0.097, so that it has a significant thermal stability allowing it to be exposed to temperatures up to at 370 ° C for at most 90 min, while having its electrical properties preserved.
    In addition, it appears that the sensitive material V0xB o , o97 has a relative variation in the even electrical resistivity as a function of the temperature T r which is particularly low, here less than 0.2% / ° C, when the temperature d thermal exposure 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.
    FIG. 2B illustrates examples of changes in 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 different quantities of added carbon. These examples thus demonstrate the increase in the range of thermal stability that the sensitive material exhibits when it contains a sufficient quantity of carbon. In these examples, the sample of the sensitive material VOx is obtained in an identical manner to that described above. The samples of the sensitive material VO X C Z were obtained in a similar manner, that is to say by implantation of carbon in a material VOx obtained beforehand by IBS spraying.
    The curve C1 is identical to that described above. The curves C2 'to C5' illustrate the evolution of the electrical resistivity p a | r as a function of the temperature Tr for a sensitive material of the VOxCz type, where the quantity z of carbon, that is to say the number of carbon atoms on that of vanadium, is here equal to 0.008 (C2 ′) , 0.016 (C3 '), 0.033 (C4'), and 0.063 (C5 '), which corresponds respectively to an atomic proportion of carbon equal to 0.27% (C2'), 0.53% (C3 '), 1.1% (C4 ') and 2.1% (C5'). The quantity x of oxygen remains identical to that of the curve Cl. It appears that the threshold temperature Tth, at which the even electrical resistivity is at least equal to 50% of the native value p a , increases as the amount z of carbon in the sensitive material. Thus, it goes from 29O ° C for VOxCo.oos and 282 ° C for VOxCo, oi6, to 294 ° C for VOxCo, o33> and to 316 ° C for VOxC o , o6 3 .
    The table below brings together the threshold values Tth of thermal exposure temperature as a function of the different z values of the amount of carbon contained in the sensitive material:
    Amount z of carbon added Threshold temperature Tth C5 ’: VOxCz with z = 0.063 316 ° C C4 ’: VOxCz with z = o, O33 294 ° C C3 ’: VOxCz with z = o, oi6 282 ° C C2 ’: VOxCz with z = o, oo8 29o C. Ci: VOx with x = i, 94; z = o 257 ° C
    Thus, the effective amount of carbon 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 greater than 0.033 and less than 0.063. Also, it is particularly advantageous for the sensitive material based on vanadium oxide to contain at least a quantity z of carbon at least equal to 0.063, so that it exhibits a significant thermal stability allowing it to be exposed to temperatures at more equal to 316 ° C for at most 90min, while having its electrical properties preserved.
    In addition, it appears that the sensitive material VOxCo, o63 has a relative variation in the electrical resistivity p a | r as a function of the particularly low temperature Tr, here less than 1.2% / ° C, when the temperature of thermal exposure 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 10, and advantageously, to a method of collective production of a matrix of bolometers 10 of a detection device 1 .
    The manufacturing method comprises at least one step during which the sensitive material 15 of the microbolometers 10 is subjected to a temperature Tr for the duration Atr.
    The manufacturing process then comprises a prior step of determining the effective value of the quantity of at least one additional chemical element chosen from boron and carbon from which the sensitive material 15, having been exposed to the temperature T r during the duration Atr, has an electrical resistivity p a | r at room temperature, at least equal to 50% of its native value p a .
    During 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 at least one of said additional chemical elements B, C, that is to say an amount of boron and / or carbon 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 ion implantation of at least one of the additional chemical elements B, C in a thin layer of the base compound (vanadium oxide VOx) previously deposited. The atmosphere is oxidizing during the production of the thin layer of VOx and the partial pressure of oxygen can be of the order of approximately 1 5 to 10'4 Torr, for example equal to 6.10'5 Torr, depending on the value. desired native of the electrical resistivity of the sensitive material. The value of the partial pressure of oxygen as well as the content of additional chemical element of the target can be obtained from calibration curves previously obtained. Other production techniques can be used, such as the ALD deposit (Atomic Loyer Deposition), or the deposition of the sensitive material by cathode sputtering in reactive mode with a metal or vanadium oxide target, followed by implantation of the 'additional chemical element.
    It is then possible to cover the base compound with the protective layer of silicon nitride, with a thickness for example of μm deposited by PECVD. The addition of the chemical element, for example boron, can then be carried out by carrying out several successive implantations. Thus, for a thin layer of the basic compound VOx of 8 μm thick covered with the protective layer of SiN of 3 μm thick, three successive implantations of boron can be carried out, starting from doses of the order of 10 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, under an oxidizing atmosphere containing CO or CO2.
    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 Tr for a period of time less than or equal to Δΐ Γ . 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 of the 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 (12)
    [1" id="c-fr-0001]
    1. Method for manufacturing at least one microbolometer (îo) comprising a sensitive material (15) based on vanadium oxide (VOx) comprising at least one additional chemical element chosen from boron (B), carbon (C ), with the exception of nitrogen (N), comprising the following stages:
    i. determination of a so-called non-zero effective quantity of the additional chemical element (B, C) from which the sensitive material (15), having undergone a step of exposure to a temperature T r for a predetermined duration Atr, presents 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 (B, C) greater than or equal to the effective quantity previously determined;
    iii. exposure of the sensitive material (15) to a temperature greater than ambient temperature and less than or equal to T r 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) comprising at least one additional chemical element chosen from boron (B) and carbon (C) , with the exception of nitrogen (N), the amount of which is greater than or equal to a so-called effective amount giving the sensitive material (15) a value p a | r of electrical resistivity at room temperature, after exposure to a temperature at 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, in which the sensitive material (15) comprises an amount of boron, defined as the ratio of the number of boron atoms to that of vanadium, at least equal to 0.097.
    [9" id="c-fr-0009]
    9. Microbolometer (10) according to claim 7 or 8, wherein the sensitive material (15) comprises an amount of carbon, defined as the ratio of the number of carbon atoms to that of vanadium, at least equal to 0.063.
    [10" id="c-fr-0010]
    10. Device for detecting (1) electromagnetic radiation, comprising a matrix of microbolometers according to any one of claims 7 to 9.
    [11" id="c-fr-0011]
    11. Detection device (1) according to claim 10, 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.
    [12" id="c-fr-0012]
    12. Detection device (1) according to claim 10 or 11, each sensitive material (15) being covered by a protective layer (22) made of silicon nitride.
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    同族专利:
    公开号 | 公开日
    US20220049991A1|2022-02-17|
    US20210048346A1|2021-02-18|
    CN111699369A|2020-09-22|
    EP3752805A1|2020-12-23|
    KR20200120687A|2020-10-21|
    CA3089611A1|2019-08-22|
    US11193833B2|2021-12-07|
    FR3077879B1|2021-08-27|
    WO2019158864A1|2019-08-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20110315981A1|2010-06-24|2011-12-29|University Of Electronic Science And Technology Of China|Microbolometer for infrared detector or Terahertz detector and method for manufacturing the same|
    CN101915620A|2010-08-20|2010-12-15|电子科技大学|Vanadium oxide thin film for microbolometer and preparation method thereof|
    EP2894444A1|2014-01-08|2015-07-15|Commissariat A L'energie Atomique Et Aux Energies Alternatives|Sensitive material for bolometric detection|WO2022023664A1|2020-07-29|2022-02-03|Lynred|Infrared imaging microbolometer and associated production methods|
    FR3113126A1|2020-07-29|2022-02-04|Lynred|INFRARED IMAGING MICRO-BOLOMETER AND RELATED METHODS|US8329002B1|2009-03-10|2012-12-11|4Wave, Inc.|Thin films and methods and machines for forming the thin films|
    JP5964543B2|2010-06-15|2016-08-03|日本電気株式会社|Bolometer type terahertz wave detector|
    AU2014238008B2|2013-03-15|2018-11-08|Icu Medical, Inc.|Medical connector|
    FR3023974B1|2014-07-18|2016-07-22|Ulis|METHOD FOR MANUFACTURING A DEVICE COMPRISING A VACUUM HERMETIC CASE AND A GETTER|
    FR3033045B1|2015-02-20|2020-02-28|Commissariat A L'energie Atomique Et Aux Energies Alternatives|ELECTROMAGNETIC RADIATION DETECTION DEVICE WITH HERMETIC ENCAPSULATION STRUCTURE WITH RELEASE VENT|
    US20160273968A1|2015-03-16|2016-09-22|Vlad Joseph Novotny|Sealed Infrared Imagers and Sensors|
    FR3077878B1|2018-02-15|2022-02-04|Commissariat Energie Atomique|METHOD FOR MANUFACTURING A SENSITIVE MATERIAL MICROBOLOMETER BASED ON VANADIUM OXIDE|
    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 |
    2021-02-26| PLFP| Fee payment|Year of fee payment: 4 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1800141|2018-02-15|
    FR1800141A|FR3077879B1|2018-02-15|2018-02-15|METHOD OF MANUFACTURING A SENSITIVE MATERIAL MICROBOLOMETER BASED ON VANADIUM OXIDE|FR1800141A| FR3077879B1|2018-02-15|2018-02-15|METHOD OF MANUFACTURING A SENSITIVE MATERIAL MICROBOLOMETER BASED ON VANADIUM OXIDE|
    CN201980012309.3A| CN111699369A|2018-02-15|2019-02-14|Method for manufacturing a microbolometer comprising a sensitive material based on vanadium oxide|
    US16/969,302| US11193833B2|2018-02-15|2019-02-14|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
    EP19710454.0A| EP3752805A1|2018-02-15|2019-02-14|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
    PCT/FR2019/050327| WO2019158864A1|2018-02-15|2019-02-14|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
    KR1020207026118A| KR20200120687A|2018-02-15|2019-02-14|Method for manufacturing a microborometer comprising a vanadium oxide-based sensitive material|
    CA3089611A| CA3089611A1|2018-02-15|2019-02-14|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
    US17/502,591| US20220049991A1|2018-02-15|2021-10-15|Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material|
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