Gas sensor

Abstract

To provide a gas sensor which can increase the sensitivity of detection.SOLUTION: A gas sensor 100 includes a laminate body 11 in which electrode layers 31, 32 and an insulation layer 24 are alternately laminated on each other. The laminate body 11 has an inclined surface 11C in at least a part of a side surface and the inclined surface 11C functions as a detection unit which detects a specific component of a measurement target gas.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to gas sensors. [Background technology]

[0002] Conventionally, the technology described in Patent Document 1 is known as a sensor. Specifically, Patent Document 1 discloses a sensor in which a first Au layer is formed on a silicon substrate, and a second Au layer is formed by separating the first Au layer from the first Au layer using Al2O3, thereby forming a nanogap equivalent to the thickness of Al2O3. When a solution is injected into the nanogap, this sensor can detect a specific substance through a change in the electrical properties at both ends of the nanogap. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-234799 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to improve the detection sensitivity of a specific substance in the configuration disclosed in Patent Document 1. However, in the past, no study was made on the structure of the electrode layer of the sensor in order to improve the detection sensitivity of a specific substance.

[0005] The present disclosure is a technology completed based on the above circumstances, and one of its objects is to provide a gas sensor capable of improving detection sensitivity. [Means for solving the problem]

[0006] The gas sensor of the present disclosure is a gas sensor comprising a laminate in which electrode layers and insulating layers are alternately stacked, and the laminate has an inclined surface on at least a portion of its side surface, and the inclined surface functions as a detection portion for detecting a specific component of the measured gas. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a gas sensor capable of improving detection sensitivity. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing a schematic diagram of a gas sensor device according to a first embodiment; [Diagram 2] FIG. 1 is a cross-sectional view of a portion of a gas sensor. [Diagram 3] Enlarged cross-sectional view of the inclined surface of the laminate [Figure 4] FIG. 13 is a cross-sectional view showing a partial configuration of a gas sensor according to a second embodiment. [Diagram 5] FIG. 11 is a plan view showing a schematic diagram of a gas sensor device according to a third embodiment; [Figure 6] FIG. 1 is a cross-sectional view of a portion of a gas sensor. [Figure 7] FIG. 13 is a cross-sectional view showing a partial configuration of a gas sensor according to a fourth embodiment. [Figure 8] FIG. 13 is an enlarged cross-sectional view of the vicinity of the inclined surface of the laminate according to the fifth embodiment. [Figure 9] FIG. 13 is an enlarged cross-sectional view of the vicinity of the inclined surface of the laminate according to the sixth embodiment. [Figure 10] FIG. 13 is an enlarged cross-sectional view of the vicinity of an inclined surface of a laminate according to a seventh embodiment. [Figure 11] FIG. 13 is an enlarged cross-sectional view of the vicinity of the inclined surface of the laminate according to the eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First, embodiments of the present disclosure will be listed and described. (1) The gas sensor of the present disclosure is a gas sensor including a laminate in which electrode layers and insulating layers are alternately stacked, and the laminate has an inclined surface on at least a portion of a side surface, and the inclined surface functions as a detection portion for detecting a specific component of a measured gas.

[0010] (2) In the gas sensor described in (1), the laminate has a specific electrode layer in at least one of the top and bottom layers, the specific electrode layer being connected to the inclined surface and having a horizontal surface extending perpendicular to the stacking direction, and a sensitive film is in contact with the side surface of the laminate over the entire stacking direction, and the sensitive film may be in contact from the horizontal surface to a portion of the inclined surface that is connected to the horizontal surface.

[0011] (3) In the gas sensor described in (2), the top layer and the bottom layer of the laminate may both be the specific electrode layer having the horizontal surface, and the sensitive film may be in contact with a portion of the inclined surface that is continuous with the horizontal surface from the horizontal surface of both the top layer and the bottom layer.

[0012] (4) In the gas sensor according to (2) or (3), the specific electrode layer may be inclined from a horizontal surface of the specific electrode layer itself to form a part of the inclined surface.

[0013] (5) In the gas sensor described in any one of (2) to (4), it is preferable that the surface of the laminate has a horizontal plane extending perpendicular to the stacking direction and an inclined plane connected to the horizontal plane and inclined with respect to the stacking direction, and the angle of the inclined plane is larger for the electrode layer than for the insulating layer. This makes it easier to place the sensitive film on the insulating layer.

[0014] (6) In the gas sensor described in any one of (1) to (5), it is preferable that the surface of the laminate has a horizontal plane extending perpendicular to the stacking direction and an inclined plane connected to the horizontal plane and inclined with respect to the stacking direction, and the angle of the inclined plane is larger for the insulating layer than for the electrode layer. In this way, the gap between the electrodes can be shortened while keeping the distance between the electrodes constant.

[0015] (7) In the gas sensor described in any one of (1) to (6), it is preferable that a heater capable of heating the laminate is provided inside the insulating layer, and the heater is positioned so as not to overlap the inclined surface when viewed from the stacking direction. This can prevent the edge of the heater from causing a crack in the sensitive film.

[0016] <Embodiment 1> A first embodiment of the present disclosure will be described with reference to FIG. 1 and the like. In this embodiment, a gas sensor 100 capable of detecting a specific gas (measurement gas) is illustrated. In addition, in FIG. 2 and FIG. 3, the Z direction is the stacking direction, and the X direction perpendicular to the Z direction is the horizontal direction. In addition, the front side of the paper in FIG. 1 and the upper side of the paper in FIG. 2 and FIG. 3 are the front side (upper side in the stacking direction) of the gas sensor 100, and the rear side of the paper in FIG. 1 and the lower side of the paper in FIG. 2 and FIG. 3 are the back side (lower side in the stacking direction) of the gas sensor 100.

[0017] As shown in Fig. 1, the gas sensor 100 includes a flat substrate 10, a laminate 11 laminated on the surface of the substrate 10, and a first wiring 15 and a second wiring 16 disposed on the surface of the substrate 10 and connected to the laminate 11. The substrate 10 is made of, for example, silicon. The gas sensor 100, together with a power source 2 and an ammeter 3, constitutes a gas sensor device 1. The power source 2 is connected to the first wiring 15 and the ammeter 3. The ammeter 3 is connected to the second wiring 16.

[0018] As shown in FIG. 2, the laminate 11 includes a plurality of electrode layers 31 and 32 and a plurality of insulating layers 21, 22, 23, 24, and 25 stacked in the stacking direction (vertical direction). Specifically, the first insulating layer 21, the second insulating layer 22, and the third insulating layer 23 are stacked in this order on the surface of the substrate 10. The first electrode layer 31, the fourth insulating layer 24, the second electrode layer 32, and the fifth insulating layer 25 are stacked in this order on the surface of the third insulating layer 23. For the layers from the third insulating layer 23 to the fifth insulating layer 25, the plurality of insulating layers 23, 24, and 25 and the plurality of electrode layers 31 and 32 are alternately stacked in the stacking direction. As shown in FIG. 3, the first electrode layer 31, the fourth insulating layer 24, the second electrode layer 32, and the fifth insulating layer 25 are defined as the main layer portion 12.

[0019] In the stacking direction, the distance between the first electrode layer 31 and the second electrode layer 32 (the thickness of the fourth insulating layer 24) is on the order of nanometers, and may be, for example, 1 nm or more and less than 1000 nm, less than 100 nm, or several tens of nm. The first electrode layer 31 is connected to the first wiring 15 shown in FIG. 1. The second electrode layer 32 is connected to the second wiring 16.

[0020] The material of each electrode layer 31, 32 and each wiring 15, 16 is not particularly limited, but may be any conductive material, for example, one or more of metals such as aluminum, copper, gold, platinum, etc. The material of each insulating layer 21, 22, 23, 24, 25 is not particularly limited, but may be any non-conductive material, for example, compounds such as SiO2 and Si3N4, etc. A heater 50 capable of heating the laminate 11 is provided inside the second insulating layer 22.

[0021] As shown in Figure 2, surface 11A of laminate 11 includes a first horizontal surface 11B which is a surface extending perpendicularly (horizontally) to the stacking direction, a second horizontal surface 11D which is a surface extending perpendicularly to the stacking direction and is arranged above first horizontal surface 11B, and an inclined surface 11C which is connected to first horizontal surface 11B and second horizontal surface 11D and is a surface inclined with respect to the stacking direction.

[0022] The first electrode layer 31 includes a thin layer portion 36, a thick layer portion 38 that is thicker than the thin layer portion 36, and a gradually changing layer portion 37 that is disposed between the thin layer portion 36 and the thick layer portion 38 and whose thickness gradually changes in the horizontal direction. The thick layer portion 38 is thicker than the second electrode layer 32. As shown in Fig. 3, a fourth insulating layer 24 is laminated on a surface (upper surface) 38A of the thick layer portion 38.

[0023] The first horizontal surface 11B is the surface (upper surface) of the thin layer portion 36. The inclined surface 11C is a side surface of the first electrode layer 31, and is a surface formed by connecting the side surface 37A of the gradually changing layer portion 37, the side surface 24A of the fourth insulating layer 24, the side surface 32A of the second electrode layer 32, and the side surface 25A of the fifth insulating layer 25. The inclined surface 11C is a side surface of the main layer portion 12 in the laminate 11. The second horizontal surface 11D is the surface (upper surface) of the fifth insulating layer 25. The inclined surface 11C functions as a detection unit capable of detecting a specific gas (a specific component of a measurement gas such as air).

[0024] The first electrode layer 31 is the bottom layer in the main layer portion 12, and is a specific electrode layer having a first horizontal surface 11B continuing to the inclined surface 11C. The first electrode layer 31 as a specific electrode layer has a side surface 37A of the gradually changing layer portion 37 that rises at an angle from the first horizontal surface 11B of the first electrode layer 31 itself and forms a part of the inclined surface 11C. The angle θ of the corner portion 39 formed by the first horizontal surface 11B and the inclined surface 11C (or the side surface 37A) is an obtuse angle greater than 90 degrees, and specifically, is preferably 120 degrees or more and 150 degrees or less, and particularly preferably 130 degrees or more and 140 degrees or less.

[0025] The gas sensor 100 includes a sensitive film 40 that contacts the entire side surface (inclined surface 11C) of the laminate 11 in the stacking direction (the entire surface of the inclined surface 11C). The sensitive film 40 also contacts from the first horizontal surface 11B to the side surface 37A of the gradually changing layer portion 37 (a portion of the inclined surface 11C that continues to the first horizontal surface 11B). The sensitive film 40 contacts the corner portion 39. Furthermore, the sensitive film 40 contacts from the inclined surface 11C to the second horizontal surface 11D.

[0026] The sensitive film 40 is configured to change its own electrical characteristics (e.g., resistance value) in response to a specific gas. The material of the sensitive film 40 may be appropriately selected according to the gas to be detected, and is not particularly limited. For example, an oxide semiconductor film may be used. As the oxide semiconductor film, any of ZnO, SnO2, WO3, In2O3, TiO2, and V2O5 may be used. In the gas sensor 100, when a specific gas reacts with the sensitive film 40 and the resistance value of the sensitive film 40 changes, the current value of the ammeter 3 connected to the power source 2 in the gas sensor device 1 changes. This allows the gas sensor device 1 to detect the specific gas.

[0027] The manufacturing method of the gas sensor 100 is not particularly limited. For example, in the step of forming the laminate 11, ion etching may be performed from the front surface side of the fifth insulating layer 25 to form the inclined surface 11C and the first horizontal surface 11B.

[0028] Next, the effects of this embodiment will be described. The gas sensor 100 of this embodiment includes a laminate 11 in which electrode layers 31, 32 and insulating layers 24 are alternately laminated, and the laminate 11 has an inclined surface 11C on at least a part of a side surface thereof, and the inclined surface 11C functions as a detection portion for detecting a specific component of a measurement gas.

[0029] With such a configuration, it is possible to increase the area of ​​the region in which specific components of the measured gas can be detected, thereby improving the detection sensitivity, compared to, for example, a case in which the portion functioning as the detection portion on the side of the laminate 11 extends in the vertical direction.

[0030] The laminate 11 has a specific electrode layer 31 in at least one of the top and bottom layers, which is connected to the inclined surface 11C and has a horizontal surface 11B extending perpendicular to the stacking direction, and a sensitive film 40 is in contact with the side of the laminate 11 throughout the entire stacking direction, and the sensitive film 40 is in contact with the horizontal surface 11B and the portion of the inclined surface 11C that is connected to the horizontal surface 11B.

[0031] According to this configuration, the gas sensor 100 includes the sensitive film 40 that contacts the side surface of the laminate 11, which is made up of the alternately stacked electrode layers 31, 32 and the insulating layer 24, over the entire stacking direction, so that the measured gas reacts with the sensitive film 40, causing a change in the electrical properties (e.g., resistance value) of the sensitive film 40, thereby enabling the measurement gas to be detected with good sensitivity and selectivity through the electrode layers 31, 32. In addition, the laminate 11 includes the specific electrode layer 31 having the inclined surface 11C and the horizontal surface 11B arranged on at least a part of the side surface, and the sensitive film 40 contacts the horizontal surface 11B to the portion of the inclined surface 11C that is continuous with the horizontal surface 11B. This makes it possible to provide the gas sensor 100 with improved detection sensitivity by increasing the contact area with the sensitive film 40 and obtaining an anchor effect, as compared to a case in which the side surface of the laminate 11 extends in the vertical direction. Here, when the horizontal plane and the side of the laminate are perpendicular to each other and the sensitive film is in contact with them, or when multiple electrode layers are arranged on the surface of the insulating layer and the sensitive film is in contact with them, the sensitive film is bent (for example, at a right angle) to follow the shape of the electrode layers, etc., and there is a risk of cracks or breaks occurring at the bent parts (this is called a step break). However, according to the gas sensor 100 described above, the sensitive film 40 is in contact with the horizontal plane 11B and the part of the inclined plane 11C that is connected to the horizontal plane 11B, so that it is possible to avoid the sensitive film 40 being bent at least at a right angle. This makes it possible to achieve a configuration in which the contact area between each layer and the sensitive film 40 is increased while suppressing step breaks.

[0032] The specific electrode layer 31 rises at an incline from its own horizontal surface 11B and forms a part of the inclined surface 11C.

[0033] In such a gas sensor 100, the specific electrode layer 31 rises at an angle from its own horizontal surface 11B to form a part of the inclined surface 11C, and the sensitive film 40 is in contact with the horizontal surface 11B to a portion of the inclined surface 11C that is continuous with the horizontal surface 11B, so that the contact area with the sensitive film 40 can be further increased and the detection sensitivity can be improved. Also, since the sensitive film 40 is in contact with the horizontal surface 11B and the inclined surface of one electrode layer 31 (specific electrode layer 31), it is possible to achieve a structure in which the sensitive film 40 is in sufficient contact with the electrode layer 31.

[0034] <Embodiment 2> Next, a second embodiment of the present disclosure will be described with reference to Fig. 4. In this embodiment, the same components as those in the above embodiment are designated by the same reference numerals, and redundant descriptions of the structure, operation, and effects will be omitted.

[0035] In the gas sensor 200, the laminate 211 includes a plurality of electrode layers 231, 232R, and 232L, and a plurality of insulating layers 21, 22, 23, 224R, 224L, and 225 stacked in a stacking direction (vertical direction). A first electrode layer 231, a fourth insulating layer 224R and 224L, a second electrode layer 232R and 232L, and a fifth insulating layer 225 are stacked in this order on the surface of the third insulating layer 23. For the layers from the third insulating layer 23 to the fifth insulating layer 225, a plurality of insulating layers 23, 224R, 224L, and 225, and a plurality of electrode layers 231, 232R, and 232L are stacked alternately in the stacking direction. The second electrode layers 232R and 232L and the fourth insulating layers 224R and 224L include those arranged on the right side of the paper with respect to a first horizontal surface 211B described later (the second electrode layer 232R and the fourth insulating layer 224R) and those arranged on the left side of the paper with respect to the first horizontal surface 211B (the second electrode layer 232L and the fourth insulating layer 224L). The first electrode layer 231, the fourth insulating layer 224R on the right side, and the second electrode layer 232R on the right side are referred to as a main layer portion 212.

[0036] The surface 211A of the laminate 211 comprises a first horizontal surface 211B which is a surface that extends horizontally, a second horizontal surface 211D which is also a horizontal surface and is arranged above the first horizontal surface 211B, and a first inclined surface (inclined surface) 211C which is connected to the first horizontal surface 211B and the second horizontal surface 211D and is a surface that is inclined with respect to the stacking direction. In addition, surface 211A is provided with a third horizontal surface 211F which is a horizontally extending surface and is arranged above first horizontal surface 211B and below second horizontal surface 211D, a second inclined surface 211E which is connected to first horizontal surface 211B and third horizontal surface 211F and is a surface which is inclined with respect to the stacking direction, a fourth horizontal surface 211H which is a horizontally extending surface and is arranged above second horizontal surface 211D, and an end surface 211G which is connected to third horizontal surface 211F and fourth horizontal surface 211H and is along the stacking direction.

[0037] The first electrode layer 231 includes a thin layer portion 236, thick layer portions 238R, 238L that are thicker than the thin layer portion 236, and gradually changing layer portions 237R, 237L that are arranged between the thin layer portion 236 and the thick layer portions 238R, 238L and have a gradually changing thickness in the horizontal direction. The thick layer portions 238R, 238L are thicker than the second electrode layers 232R and 232L. The gradually changing layer portions 237R, 237L and the thick layer portions 238R, 238L include those (237R, 238R) arranged on the right side of the thin layer portion 236 in the drawing and those (237L, 238L) arranged on the left side of the thin layer portion 236 in the drawing.

[0038] The first horizontal surface 211B is the surface of the thin layer portion 236. The first inclined surface 211C is a part of the side surface (the first inclined surface 211C, the second inclined surface 211E, and the end surface 211G) of the laminate 211, and is the side surface of the main layer portion 212. The first inclined surface 211C is a surface where the side surface of the right gradually-changing layer portion 237R, the side surface of the right fourth insulating layer 224R, and the side surface of the right second electrode layer 232R are connected. The second inclined surface 211E is a surface where the side surface of the left gradually-changing layer portion 237L and the side surface of the left fourth insulating layer 224L are connected. The third horizontal surface 211F is the surface (upper surface) of the left fourth insulating layer 224L. The end surface 211G is a surface formed by joining the end surface of the left second electrode layer 232L and the end surface of the fifth insulating layer 225. The fourth horizontal surface 211H is the surface (upper surface) of the fifth insulating layer 225.

[0039] In the laminate 211, the bottom layer (first electrode layer 231) and the top layer (second electrode layer 232R on the right side) in the main body layer portion 212 are both specific electrode layers having horizontal surfaces 211B, 211D. The first electrode layer 231 is the bottom layer in the main body layer portion 212 and is considered to be a first specific electrode layer having a first horizontal surface 211B continuing to the inclined surface 211C. The second electrode layer 232R on the right side is the top layer in the main body layer portion 212 and is considered to be a second specific electrode layer having a second horizontal surface 211D continuing to the inclined surface 211C. The sensitive film 240 contacts the horizontal surfaces 211B, 211D of both the bottom layer (first electrode layer 231) and the top layer (right-side second electrode layer 232R) with the portions (inclined ends 211C1, 211C2) of the inclined surface 211C continuing to the horizontal surfaces 211B, 211D. With this configuration, the contact area between the stack 211 and the sensitive film 240 can be increased, improving the detection sensitivity.

[0040] The sensitive film 240 is in contact with the entire surface 211A of the laminate 211. Specifically, the sensitive film 240 is in contact with the first horizontal surface 211B, the first inclined surface 211C, the second horizontal surface 211D, the second inclined surface 211E, the third horizontal surface 211F, the end surface 211G, and the fourth horizontal surface 211H.

[0041] <Embodiment 3> Next, a third embodiment of the present disclosure will be described with reference to Figures 5 and 6. In this embodiment, the same components as those in the above embodiment are designated by the same reference numerals, and redundant descriptions of the structure, operation, and effects will be omitted.

[0042] 5, the gas sensor 300 includes a first wiring 315 and a second wiring 316 connected to a laminate 311. The first wiring 315 branches into a rear side wiring 315A and a front side wiring 315B. Similarly, the second wiring 316 branches into a rear side wiring 316A and a front side wiring 316B. The gas sensor 300, together with a power source 2 and an ammeter 3, constitutes a gas sensor device 301.

[0043] As shown in FIG. 6, the laminate 311 includes a plurality of electrode layers 31, 32, 333, 334 and a plurality of insulating layers 21, 22, 23, 24, 25, 326, 327 stacked in the stacking direction (vertical direction). A third electrode layer 333, a sixth insulating layer 326, a fourth electrode layer 334, and a seventh insulating layer 327 are stacked in this order on the surface of the fifth insulating layer 25. The first electrode layer 31 is connected to the back side wiring 315A of the first wiring 315 shown in FIG. 1. The second electrode layer 32 is connected to the back side wiring 316A of the second wiring 316. The third electrode layer 333 is connected to the front side wiring 315B of the first wiring 315. The fourth electrode layer 334 is connected to the front side wiring 316B of the second wiring 316.

[0044] In the surface 311A ​​of the laminate 311, the first horizontal surface 311B is the surface (upper surface) of the thin layer portion 36. The inclined surface 311C is a surface formed by connecting the side surface of the gradually changing layer portion 37, the side surface of the fourth insulating layer 24, the side surface of the second electrode layer 32, the side surface of the fifth insulating layer 25, the side surface of the third electrode layer 333, the side surface of the sixth insulating layer 326, the side surface of the fourth electrode layer 334, and the side surface of the seventh insulating layer 327. The second horizontal surface 311D is the surface (upper surface) of the seventh insulating layer 327. The sensitive film 340 is in contact with the first horizontal surface 311B to the inclined surface 311C, and further from the inclined surface 311C to the second horizontal surface 311D.

[0045] <Embodiment 4> Next, a fourth embodiment of the present disclosure will be described with reference to Fig. 7. In this embodiment, the arrangement of the heater 50 in the first embodiment is changed, and the same reference numerals are used for the same parts as in the first embodiment, and redundant explanations of the structure, action, and effect will be omitted.

[0046] 7, the laminate 11 of the gas sensor 400 includes a plurality of electrode layers 31 and 32 and a plurality of insulating layers 21, 22, 23, 24, and 25 stacked in a stacking direction (vertical direction). A heater 50 capable of heating the laminate 11 is provided inside the second insulating layer 22.

[0047] The surface 11A of the laminate 11 includes a first horizontal surface 11B that is a surface extending perpendicularly (horizontally) to the stacking direction, a second horizontal surface 11D that is a surface extending perpendicularly to the stacking direction and is disposed above the first horizontal surface 11B, and an inclined surface 11C that is connected to the first horizontal surface 11B and the second horizontal surface 11D and is inclined with respect to the stacking direction. When viewed from the stacking direction, the heater 50 is disposed so as not to overlap the inclined surface 11C but to overlap the first horizontal surface 11B. If the heater is disposed so as to overlap the inclined surface, there is a risk that the sensitive film 40 will crack and the sensitive film 40 will not function properly, so in this embodiment, the heater 50 is disposed so as not to overlap the inclined surface 11C.

[0048] <Embodiment 5> Next, a fifth embodiment of the present disclosure will be described with reference to Fig. 8. In this embodiment, the shape of the inclined surface 11C of the first embodiment is changed, and the same reference numerals are used for the same parts as those of the first embodiment, and redundant explanations of the structure, action, and effect will be omitted.

[0049] 8, the laminate 511 of the gas sensor 500 includes a plurality of electrode layers 531, 532 and a plurality of insulating layers 23, 524, 525 laminated in a lamination direction (vertical direction). The first electrode layer 531, the fourth insulating layer 524, the second electrode layer 532, and the fifth insulating layer 525 form a main layer portion 512.

[0050] Surface 511A of laminate 511 includes a first horizontal surface 511B which is a surface extending perpendicularly (horizontally) to the stacking direction, a second horizontal surface 511D which is a surface extending perpendicularly to the stacking direction and is arranged above first horizontal surface 511B, and an inclined surface 511C which is connected to first horizontal surface 511B and second horizontal surface 511D and is a surface inclined with respect to the stacking direction.

[0051] Inclined surface 511C is a side surface of first electrode layer 531, and is a surface formed by connecting side surface 537A of gradual-change layer portion 537, side surface 524A of fourth insulating layer 524, side surface 532A of second electrode layer 532, and side surface 525A of fifth insulating layer 525. Inclined surface 511C is a side surface of main body layer portion 512 in laminate 511.

[0052] Top surface 538A of first electrode layer 531 is parallel to first horizontal plane 511B. An angle of side surface 524A of fourth insulating layer 524 that forms an acute angle with first horizontal plane 511B is equal to angle θ1 of side surface 524A of fourth insulating layer 524 that forms an acute angle with top surface 538A of first electrode layer 531. Angle θ1 is the angle of inclined surface 511C of fourth insulating layer 524.

[0053] The top surface of the fourth insulating layer 524 is parallel to the first horizontal plane 511B. The angle of the side surface 532A of the second electrode layer 532 that forms an acute angle with the first horizontal plane 511B is equal to the angle θ2 of the side surface 532A of the second electrode layer 532 that forms an acute angle with the top surface of the fourth insulating layer 524. The angle θ2 is the angle of the inclined surface 511C of the second electrode layer 532.

[0054] In this embodiment, since the angle θ1 is greater than the angle θ2, it becomes easier to arrange the sensitive film 540 on the side surface 532A of the second electrode layer 532.

[0055] <Embodiment 6> Next, a sixth embodiment of the present disclosure will be described with reference to Fig. 9. In this embodiment, the shape of the inclined surface 511C of the fifth embodiment is changed, and the same reference numerals are used for the same parts as in the fifth embodiment, and redundant explanations of the structure, action, and effect will be omitted. For configurations corresponding to the fifth embodiment, the reference numerals are used in which the digit in the hundreds digit of the numeral portion is changed from 5 to 6.

[0056] In this embodiment, since the angle θ2 is greater than the angle θ1, the gap between the first electrode layer 631 and the second electrode layer 632 can be shortened while keeping the distance between them constant.

[0057] Next, a seventh embodiment of the present disclosure will be described with reference to Fig. 10. In this embodiment, a deviation occurs in the inclined surface 11C of the first embodiment, and the same reference numerals are used for the same parts as in the first embodiment, and a duplicated description of the structure, action, and effect will be omitted. For configurations corresponding to the first embodiment, reference numerals are used with 7 added to the hundreds digit of the numeral portion.

[0058] In this embodiment, a side surface 724A of the fourth insulating layer 724 and a side surface 725A of the fifth insulating layer 725 protrude beyond the side surface 37A of the gradually changing layer portion 37 and the side surface 32A of the second electrode layer 32.

[0059] Next, an eighth embodiment of the present disclosure will be described with reference to Fig. 11. In this embodiment, a shift occurs in the inclined surface 11C of the first embodiment, and the same reference numerals are used for the same parts as in the first embodiment, and a duplicated description of the structure, action, and effect will be omitted. For configurations corresponding to the first embodiment, reference numerals are used with 8 added to the hundreds digit of the numeral portion.

[0060] In this embodiment, a side surface 824A of the fourth insulating layer 824 and a side surface 825A of the fifth insulating layer 825 are recessed from a side surface 37A of the gradually changing layer portion 37 and a side surface 32A of the second electrode layer 32.

[0061] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings, and for example, the following embodiments are also included within the technical scope of the present disclosure. Furthermore, in addition to the embodiments described below, various modifications can be made without departing from the spirit of the present disclosure.

[0062] (1) In addition to the above-mentioned embodiment, the configuration of the laminate can be appropriately changed. The laminate may have at least a first electrode layer, an insulating layer laminated on the first electrode layer, and a second electrode layer laminated on the insulating layer. In such a configuration, the upper surface of the second electrode layer may be in contact with the sensitive membrane.

[0063] (2) In addition to the above embodiment, the configuration of the sensitive film can be changed as appropriate. The sensitive film may be in contact with the first horizontal surface and the inclined surface, but not in contact with the second horizontal surface. The sensitive film may also be in contact with a part of the first horizontal surface and an inclined surface that is continuous with the part of the first horizontal surface.

[0064] (3) The configuration of the wiring can be changed as appropriate. In the above embodiment, the wiring is arranged so as to connect to both sides of the laminate (both the left and right sides of the paper in FIG. 1), but this is not limited thereto. For example, the wiring may be arranged so as to connect to the front side of the laminate (the lower side of the paper in FIG. 1).

[0065] (4) In the gas sensor device, the instrument for measuring the electrical characteristics is not limited to an ammeter that measures current, and various measuring instruments for measuring electrical characteristics, such as a voltmeter or an ohmmeter, may be used. [Explanation of symbols]

[0066] 10...substrate, 11,211,311,511,611,711,811...laminated body, 11B,211B,311B,511B,611B,711B,811B...first horizontal surface (horizontal surface), 11C,211C,311C,511C,611C,711C,811C...inclined surface, 24,224R,524,624,724,824...fourth insulating layer (insulating layer), 31,32,231,232R,531,631...electrode layer, 40,240,340,440,540,640,740,840...sensitive film, 100,200,300,400,500,600,700,800...gas sensor

Claims

1. A gas sensor including a laminate in which electrode layers and insulating layers are alternately laminated, The laminate has an inclined surface on at least a part of a side surface, The inclined surface functions as a detection portion for detecting a specific component of a measurement gas.

2. the laminate includes a specific electrode layer, at least one of an uppermost layer and a lowermost layer, which is connected to the inclined surface and has a horizontal surface extending perpendicular to the lamination direction; a sensitive film is in contact with the side surface of the stack over the entire stacking direction; 2. The gas sensor according to claim 1, wherein the sensitive film is in contact with a portion of the inclined surface that is continuous with the horizontal surface and extends from the horizontal surface to the inclined surface.

3. In the laminate, the uppermost layer and the lowermost layer are the specific electrode layers each having the horizontal surface, 3. The gas sensor according to claim 2, wherein the sensitive film is in contact with a portion of the inclined surface that is continuous with the horizontal surface of both the uppermost layer and the lowermost layer.

4. 4. The gas sensor according to claim 2, wherein the specific electrode layer rises at an incline from a horizontal surface of the specific electrode layer itself and constitutes a part of the inclined surface.

5. The surface of the laminate has a horizontal surface extending perpendicular to the lamination direction, and an inclined surface that is connected to the horizontal surface and inclined with respect to the lamination direction, 3. The gas sensor according to claim 2, wherein an angle of the inclined surface of the electrode layer is larger than that of the insulating layer.

6. The surface of the laminate has a horizontal surface extending perpendicular to the lamination direction, and an inclined surface that is connected to the horizontal surface and inclined with respect to the lamination direction, 2. The gas sensor according to claim 1, wherein an angle of the inclined surface of the insulating layer is larger than that of the electrode layer.

7. a heater capable of heating the laminate is provided inside the insulating layer, 2. The gas sensor according to claim 1, wherein the heater is disposed so as not to overlap the inclined surface when viewed from the stacking direction.

Images