• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention provides a gas sensor device (100) and a method for producing a gas sensor device (100). The gas sensor device (100) is formed with a sensor element (110) having a gas sensitive layer (120) comprising a metal oxide and a protective layer (130) partially covering the gas sensitive layer (120) of the sensor element (110) Protective layer (130) is hydrophobic and / or acts hydrophobic in cooperation with the gas-sensitive layer (120) of the sensor element (110).
    公开号:CH714156A2
    申请号:CH00979/18
    申请日:2018-08-10
    公开日:2019-03-15
    发明作者:Martinez Prada Maria；Eifert Alexander
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:

    Description: [0001] The present invention relates to a metal oxide semiconductor gas sensor device and a method of manufacturing a metal oxide semiconductor gas sensor device.
    Background Art Environmental sensors, particularly gas sensor devices for measuring indoor air quality or outdoor air, are becoming increasingly important. In particular, miniaturized systems in portable electronic devices are the focus of research and development.
    For measuring an air quality, or air quality, gas sensor devices based on metal oxide semiconductors are frequently used. The gas-sensitive layer of a semiconducting metal oxide is heated by up to a few hundred degrees in order to accelerate chemical signal formation processes and thus to generate a fast sensor response. The signal evaluation in the corresponding sensor element takes place via the measurement of the induced changes in the conductivity of the gas-sensitive layer, the capacitance and / or the work function due to the presence of the gas to be sensed or selected gas components to be sensed. Sensor elements may in particular be chips on which the gas-sensitive layer, heater structures for heating the gas-sensitive layer and optionally, further elements are arranged. Sensor elements are usually housed in housings and thus form a sensor device.
    DE 10 2013 212 478 A1 describes an apparatus or a method for detecting a concentration of a gas or a gas component and the use of such a device or such a method. It is provided that the device designed as a gas sensor at least one sensor element with a gas-sensitive layer, e.g. from a metal oxide, as well as a heating element for heating the gas-sensitive layer.
    By integration into portable, i. Mobile terminals such as smartphones and wearables (e.g., smartwatches, activity trackers, goggles whose insides serve as screens, or garments incorporating electronic communication and musical reproduction aids) are exposed to these gas sensor devices in different environmental conditions. Since the gas sensor devices have a media access (eg an opening in a housing of the mobile terminal), so that media with the gas to be sensed can reach the sensor elements, in particular the gas-sensitive layer, all other substances from the ambient air can also reach the sensor element, especially the gas-sensitive layer, get.
    Such substances from the environment, which in contrast to the detecting gas are also called "foreign gases", can lead to poisoning, i. an increasingly reduced usability of the gas sensor device, in particular the sensor element, more precisely a gas-sensitive layer (or sensor layer) of the sensor element lead.
    In US 2012/077 019 A1, a moisture barrier is proposed, which comprises a mixed matrix membrane with hydrophilic filler particles, and which can be used for gas sensors whose sensitivity decreases with increasing humidity. In contrast, metal oxide semiconductor-based gas sensor devices have increasing sensitivity with increasing humidity.
    Siloxanes have been identified as a particularly harmful foreign gas for gas sensor devices. A poisoning of the gas-sensitive layer takes place in particular in the presence of moisture, i. of water. Siloxanes are chemical compounds having the general formula R3Si- [0-SiR2] n-O-SiR3, where R can be hydrogen atoms or alkyl, allyl or aromatic groups. In contrast to the so-called silanes, the silicon atoms are not linked to each other, but by exactly one oxygen atom with their adjacent silicon atom.
    DISCLOSURE OF THE INVENTION The present invention discloses a gas sensor device having the features of claim 1 and a method having the features of claim 7.
    Accordingly, there is provided: a gas sensor device based on metal oxide semiconductor, comprising: a gas sensitive sensor element having a gas sensitive layer comprising a metal oxide; and a protective layer partially covering the gas sensitive layer of the sensor element; wherein the protective layer is hydrophobic and / or hydrophobic in cooperation with the gas-sensitive layer.
    The metal oxide semiconductor based gas sensor device may also be referred to as a MOx based gas sensor. Gas-sensitive layers which are designed in such a way (in particular have such a metal oxide) that they (as opposed to optical or electrochemical sensors) have an increasing sensitivity to the gas to be sensed with increasing humidity.
    The protective layer is preferably formed from individual long-chain molecules (in contrast to, for example, a polymer matrix), wherein preferably no filler particles are used.
    From the fact that the protective layer partially covers the gas sensitive layer, it is understood that more than 0% and less than 100% of the gas sensitive layer is covered by the protective layer, in particular more than 10% and less than 90%. The protective layer may form one or more contiguous surfaces, for example a grid-like surface which leaves openings through which the gas-sensitive layer remains accessible to the medium with the gas to be sensed. Alternatively, the protective layer can also represent a distributed, partial coating of the gas-sensitive layer without macroscopically coherent surfaces of the protective layer being formed.
    For the metal oxide of the gas-sensitive layer, for example tin (IV) oxide (SnO2), SnO, SnOx or a mixture thereof, tungsten oxide, zinc oxide, titanium dioxide or organic semiconductor materials such as MePTCDI can be used.
    Furthermore, there is provided a method of manufacturing a metal oxide semiconductor based gas sensor device, comprising the steps of: providing a sensor element with a gas sensitive layer comprising a metal oxide; and forming a protective layer partially covering the gas sensitive layer of the sensor element; wherein the protective layer is hydrophobic and / or hydrophobic in cooperation with the gas-sensitive layer of the sensor element.
    ADVANTAGES OF THE INVENTION The increasing poisoning of the gas-sensitive layer by siloxane molecules causes an increasing increase in the response time t and / or a decrease in the sensitivity to a gas to be detected and / or a decrease in the conductivity of the gas sensor device. The finding underlying the present invention is that poisoning of the gas-sensitive layer can be prevented or slowed down if the gas-sensitive layer is provided with a hydrophobic protective layer. Thus, moisture at the gas-sensitive layer can be reduced, whereby poisoning of the gas-sensitive layer is prevented or at least slowed down.
    In particular, a surface tension of the gas-sensitive layer of the sensor element can be reduced by the protective layer, for example by the application of hydrophobic long-chain molecules with 2 <n <20, where n stands for a number of atoms of the molecules. These long-chain hydrophobic molecules advantageously make it difficult to separate the water on the gas-sensitive layer, but they are still permeable to the gas to be sensed.
    Advantageous embodiments and developments emerge from the subclaims and from the description with reference to the figures.
    According to a preferred embodiment, the protective layer comprises silane molecules or consists of silane molecules.
    According to a further preferred embodiment, the protective layer of trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane or consists of trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane.
    The term silane is according to the IUPAC rules for a group of chemical compounds consisting of a silicon backbone and hydrogen. Similar groups of substances are germans and alkanes. Silanes can have a branched (iso and neo-silane) or unbranched (n-silane) structure.
    According to a further preferred embodiment, the protective layer Siloxanmoieküle or consists of siloxane molecules.
    Siloxanes are chemical compounds having the general formula R3Si- [O-SiR2] n-O-SiR3, where R can be hydrogen atoms or alkyl groups. In contrast to the silanes, the silicon atoms are not linked to each other, but by exactly one oxygen atom with their adjacent silicon atom. The trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane can be brought into the vicinity of the sensor surface of the sensor element in particular via a gas phase reaction.
    According to a further preferred development, the protective layer comprises fluorine, i. the protective layer may be a fluorine-based protective layer. According to a further preferred development, the protective layer has a self-assembling monolayer, SAM, or consists of a SAM.
    The self-assembling monolayer (self-assembled monolayer, SAM) is a component of nanotechnology. A self-assembling monolayer forms e.g. spontaneously when immersing surface-active or organic substances in a solution or suspension. Suitable substances are z. As alkanethiols, alkyltrichlorosilanes and fatty acids. These form simple monolayers with a high internal order on metals such as gold, silver, platinum and copper as well as graphite and silicon.
    In contrast to conventional coating methods such as chemical vapor deposition (CVD), SAM have a defined thickness, which ranges from 0.1 nm to several nanometers, depending on the molecule used.
    In semiconductor technology, the self-assembling monolayer is used, for example, for surface stabilization and tailor-made functionalization of electrodes. Depending on the length of the alkyl chains used, the permeability and / or the charge transfer rate are influenced.
    BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be explained in more detail below with reference to the exemplary embodiments illustrated in the schematic figures of the drawings. It shows:
    FIG. 1 is a schematic detail view of a gas sensor device according to an embodiment of the present invention; FIG. and
    2 shows a schematic detail view of a gas sensor device according to a further embodiment of the present invention.
    In all figures, the same or functionally identical elements and devices-unless otherwise indicated - provided with the same reference numerals.
    DESCRIPTION OF THE EXEMPLARY EMBODIMENTS FIG. 1 shows a schematic detail view of a gas sensor device 100 according to an embodiment of the present invention.
    The gas sensor device comprises a gas-sensitive layer 110, which is for example mounted on a substrate such as e.g. an optional application-specific integrated circuit 150 (ASIC) of the gas sensor device 100 may be arranged and / or connected to the substrate.
    The ASIC 150 can be designed to effect the current application of the gas-sensitive layer 120, as is conventional in the prior art, to detect a corresponding response signal of the gas-sensitive layer 120 influenced by the gas to be sensed and / or the gas-sensitive sensor material of the gas-sensitive layer 120 to heat and / or a signal evaluation of the response signal of the gas-sensitive layer 120, for example via the measurement of the induced changes in the conductivity, the capacity and / or the work function due to the presence of the gas to be sensed or selected to be sensed gas components perform. Finally, an output signal indicating the gas to be sensed (or a sensed gas) can also be tapped on the ASIC 150.
    For example, the ASIC 150 may be configured to heat the gas-sensitive layer 120, for example up to a few hundred degrees, to accelerate chemical signal formation processes and thus generate a faster sensor response of the gas-sensitive layer 120 and the gas sensor device 100, respectively.
    The gas sensor device 100 may also be formed without the ASIC 150 and configured such that the gas-sensitive layer 120 is connectable to an external ASIC, which may perform some or all of the functions described above in connection with the ASIC 150.
    The sensor element 110, in particular the gas-sensitive layer 120, comprises a metal oxide, in particular a metal oxide semiconductor such as tin (IV) oxide (SnO2), SnO, SnOx or a mixture thereof, tungsten oxide, zinc oxide, titanium dioxide or organic semiconductor materials like MePTCDI.
    On, in particular directly on, of the gas-sensitive layer 120, a protective layer 130 is formed which partially covers the gas-sensitive layer 120. The protective layer 130 is hydrophobic and / or acts hydrophobic in cooperation with the gas-sensitive layer 120. The protective layer 130 may comprise, for example, silane molecules or consist of silane molecules, have siloxane molecules or consist of siloxane molecules, have fluorine and / or consist of a self-assembling monolayer (SAM) or of a SAM.
    Preferably, the protective layer 130 may include both a silane and fluorine. Particularly preferably, the protective layer 130 may comprise trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane or consist of trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane.
    The trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane can be brought, for example via a gas phase reaction in the vicinity of the sensor surface 120 of the gas-sensitive layer 120. The deposition of silane molecules occurs for a limited time via the gas phase. The longer the exposure, the more homogeneous and / or more complete the coating of the gas sensitive layer 120. The coating process is terminated when the gas-sensitive layer 120 and / or the sensor element 110 has been sufficiently hydrophobized by the protective layer 130 (eg, when the protective layer 130 covers a predetermined percentage of the gas-sensitive layer 120) before the complete gas-sensitive layer 120 passes through the protective layer 130 is covered.
    The protective layer 130 is arranged such that a medium F with the gas to be detected first passes the protective layer 130 (ie, either traverses the protective layer 130 itself, or passes through gaps in the protective layer 130), before it impacts the gas sensitive layer 120 hits. Thus, water molecules present in the medium F may be advantageously rejected by the protective layer 130, i. be prevented from adsorption to the gas-sensitive layer.
    FIG. 2 shows a schematic detail view of a gas sensor device 200 according to a further embodiment of the present invention.
    权利要求:
    Claims (10)
    [1]
    claims
    A metal-oxide-semiconductor-based gas sensor device (100; 200) comprising: a gas-sensitive sensor element (110; 210) having a gas-sensitive layer (120; 220) comprising a metal oxide; and a protective layer (130; 230) partially covering the gas sensitive layer (120; 220) of the sensor element (110; 210); wherein the protective layer (130; 230) is hydrophobic and / or hydrophobic in cooperation with the sensor surface (120; 220) of the gas-sensitive layer (110; 210).
    [2]
    2. The gas sensor device (100) according to claim 1, wherein the protective layer (130) comprises stoichiocyanine molecules or consists of siloxane molecules.
    [3]
    3. The gas sensor device (100) according to claim 1 or 2, wherein the protective layer (130) comprises silane molecules or consists of silane molecules.
    [4]
    A gas sensor device (100; 200) according to any one of claims 1 to 3, wherein the protective layer (130; 230) comprises fluorine.
    [5]
    The gas sensor device (100) according to claims 3 and 4, wherein the protective layer (130) comprises trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane or consists of trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane.
    [6]
    6. Gas sensor device according to one of claims 1 to 5, wherein the protective layer comprises a self-assembling monolayer, SAM, or consists of a SAM.
    [7]
    A method of fabricating a metal oxide semiconductor based gas sensor device (100; 200), comprising the steps of: providing a gas sensitive layer (110; 210) having a gas sensitive layer (120; 220) comprising a metal oxide; and forming a protective layer (130; 230) partially covering a gas-sensitive layer (120; 220) of the sensor element (110; 210); wherein the protective layer (130; 230) is hydrophobic and / or hydrophobic in cooperation with the gas-sensitive layer (120; 220) of the sensor element (110; 210).
    [8]
    The method of claim 7, wherein the protective layer (130; 230) comprises silane molecules or consists of silane molecules.
    [9]
    The method of claim 8, wherein the protective layer (130; 230) comprises trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane or consists of trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane.
    [10]
    10. The method of claim 9, wherein trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane is brought into the vicinity of the gas-sensitive layer (120; 220) of the sensor element (110; 210) via a gas phase reaction.
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    引用文献:
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102017215310.5A|DE102017215310A1|2017-09-01|2017-09-01|Gas sensor device and method of manufacturing a gas sensor device|
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