Sensor device and method for manufacturing the same

Abstract

[Problem] To provide: a sensor device by which it is possible to improve the detection accuracy for a gas; and a method for manufacturing the same. [Solution] A sensor device according to one aspect of the present invention comprises: a substrate; a gate electrode; a source electrode; a drain electrode; and an oscillator. The gate electrode is disposed on the substrate. The source electrode is disposed on the substrate and has a first conductive layer and a second conductive layer that is provided on the first conductive layer. The drain electrode is disposed on the substrate and has a third conductive layer and a fourth conductive layer that is provided on the third conductive layer. The oscillator has: a first end part disposed between the first and the second conductive layers; a second end part disposed between the third and the fourth conductive layers; and an oscillating part that opposes the gate electrode.

Description

Technical Field

[0001] The present invention relates to a sensor device and a method for manufacturing the same.

Background Art

[0002] The gas sensor described in Non-Patent Document 1 includes a substrate, a gate electrode, a drain electrode, and a source electrode disposed on the substrate, and a graphene layer. This gas sensor has a structure that supports the graphene layer so as to be vibratable between the drain electrode and the source electrode, and detects a gas component based on a change amount of the resonance frequency of the graphene layer due to adsorption of a gas.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to perform more sensitive gas detection, it is necessary to accurately detect a change in the resonance frequency due to gas adsorption in the vibrator of the gas sensor. This means that the Q value of the vibrator needs to be high. Furthermore, in order to specify the vibration mode required for gas detection, it is required that no natural vibration mode that interferes with the desired vibration mode occurs in the vibrator.

[0005] In view of the above circumstances, an object of the present invention is to provide a sensor device capable of enhancing the detection sensitivity of a gas and a method for manufacturing the same.

Means for Solving the Problems

[0006] A sensor device according to one embodiment of the present invention includes a substrate, an insulating film, a gate electrode, a source electrode, a drain electrode, and a vibrator. The insulating film is formed on the substrate. The gate electrode is disposed on the insulating film. The source electrode has a first conductor layer and a second conductor layer provided on the first conductor layer, and is disposed on the insulating film. The drain electrode has a third conductor layer and a fourth conductor layer provided on the third conductor layer, and is disposed on the insulating film. The vibrator has a first end portion sandwiched between the first and second conductor layers, a second end portion sandwiched between the third and fourth conductor layers, and a vibrating portion facing the gate electrode.

[0007] The vibrator may include a graphene layer.

[0008] The vibrator may further include a sensitive film formed on the graphene layer.

[0009] The sensitive film may be a porous film.

[0010] The porous film may be a carbon-based material.

[0011] The first to fourth conductor layers may be the same type of metal material.

[0012] The source electrode may further have an adhesion layer disposed between the first and second conductor layers and in close contact with the vibrator, and the drain electrode may further have an adhesion layer disposed between the third and fourth conductor layers and in close contact with the vibrator.

[0013] The gate electrode may be disposed between the substrate and the vibrator.

[0014] A method for manufacturing a sensor device according to one embodiment of the present invention includes forming a lower electrode layer on a substrate. A graphene layer is formed on the lower electrode layer. An upper electrode layer is formed on the graphene layer. By patterning the lower electrode layer and the upper electrode layer, a source electrode that supports one end of the graphene layer in a vibratable manner, a drain electrode that supports the other end of the graphene layer in a vibratable manner, and a gate electrode that faces the graphene layer with a predetermined gap in the thickness direction of the graphene layer and the substrate are respectively formed.

Advantages of the Invention

[0015] According to the present invention, the gas detection sensitivity can be enhanced.

Brief Description of the Drawings

[0016]

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Best Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Overview of Gas Determination System] FIG. 1 is a schematic diagram showing the configuration of a gas determination system. FIG. 2 is a schematic diagram showing the configuration of a sensor device 10 that forms part of the gas determination system.

[0018] As shown in FIG. 1, the gas determination system 1 includes a sensor device 2, an information processing device 4, a display device 5, and a storage unit 6. The sensor device 2 includes a housing chamber 20, a sensor device 10, a UV (ultraviolet) light source 23, and a heating unit 26.

[0019] The housing chamber 20 houses the sensor device 10, the UV light source 23, and the heating unit 26. The housing chamber 20 has an intake port 21 for sucking gas from the outside and an exhaust port 22 for exhausting the gas introduced into the housing chamber 20 to the outside. A valve 24 for adjusting the inflow of gas into the housing chamber 20 is provided at the intake port 21, and a valve 25 for adjusting the outflow of gas in the housing chamber 20 to the outside is provided at the exhaust port 22.

[0020] The UV light source 23 emits ultraviolet rays (UV) that irradiate the sensor device 10. By irradiating the vibrator 16 of the sensor device 10, which will be described later, the vibrator 16 is cleaned. By performing UV irradiation, gas is efficiently adsorbed onto the vibrator 16. This is considered to be because, by performing UV irradiation, O2, H2O, etc. are removed from the surface of the vibrator 16 (cleaning effect), and a dynamic equilibrium between the adsorption and photoexcitation desorption of gas molecules on the surface of the vibrator 16 is induced, increasing the effective adsorption sites for gas on the vibrator 16, and because adsorption is accelerated by the state change (ionization, etc.) of the adsorbed molecules.

[0021] The heating unit 26 is, for example, a heater and heats the sensor device 10. By heating the sensor device 10 with the heating unit 26, the gas adsorption effect by the vibrator 16 can be obtained.

[0022] As shown in FIG. 2, the sensor device 10 includes a substrate 11, an insulating film 12, a gate electrode 13, a source electrode 14, a drain electrode 15, and a vibrator 16.

[0023] The substrate 11 is typically a silicon substrate, but may be other semiconductor substrates or glass substrates other than silicon. The insulating film 12 is formed on the substrate 11. The insulating film 12 is typically a silicon oxide film, and when the substrate 11 is a silicon substrate, it is a thermal oxide film formed on its surface.

[0024] The gate electrode 13, the source electrode 14, and the drain electrode 15 are formed on the insulating film 12. The gate electrode 13 is disposed between the source electrode 14 and the drain electrode 15. The gate electrode 13, the source electrode 14, and the drain electrode 15 are typically metal films, and in this embodiment, they are composed of a laminated film of chromium (Cr) and gold (Au).

[0025] The vibrator 16 is disposed between the source electrode 14 and the drain electrode 15 so as to face the gate electrode 13. The vibrator 16 is disposed with a gap so as not to contact the gate electrode 13. The vibrator 16 is composed of a conductive material, and in this embodiment, it is composed of a graphene layer. The graphene layer is composed of a single-layer film, but may be a multi-layer film. The vibrator 16 may also be composed of other conductive materials such as a metal film or a silicon thin film in addition to the graphene layer.

[0026] As shown in FIG. 3, the vibrator 16 is composed of a laminated film of a graphene layer 160 and a sensitive film 17 formed on its surface. The sensitive film 17 is composed of, for example, a material capable of adsorbing the gas to be detected. The material constituting the sensitive film 17 can be arbitrarily selected according to the type of the gas to be detected, and typically, an organic polymer film (organic high molecular film, organic low molecular film), an organic dye film, an inorganic film, or the like can be used.

[0027] The sensing film 17 may be a porous film. The porous film is formed by decorating the surface of the graphene layer 160 with activated carbon. The material constituting the porous film is not limited to activated carbon, and it may be more porous than the graphene layer 160 and may have conductive characteristics similar to those of the graphene layer 160. For example, carbon-based materials, conductive polymers, conductive ceramics, or porous silicon may be used as the conductive material constituting the porous layer 17. Preferably, the porous film is composed of the same carbon-based material as the graphene layer 160. A carbon-based material is a substance mainly composed of carbon.

[0028] Since the porous film functions to promote gas adsorption, it has a large adsorption surface area due to its porosity and has many dangling bonds, so it can efficiently adsorb gas. Since the porous film has conductive characteristics, compared with the case where a film having no conductive characteristics is provided as an adsorption film on the graphene layer 160, the adsorption surface area is increased and there are many dangling bonds on the surface, so gas molecule adsorption is promoted.

[0029] The thickness of the porous film is not particularly limited and may be the same as the thickness of the graphene layer 160, thinner than the thickness of the graphene layer 160, or thicker. Typically, the thickness of the graphene layer 160 is 1 nm and the thickness of the porous film is 1 nm. The porous film is formed so as to cover the entire surface of the graphene layer 160, but is not limited thereto, and may be formed so as to cover at least a part of the surface of the graphene layer 160.

[0030] The information processing device 4 includes an acquisition unit 41, a determination unit 42, an output unit 43, and a control unit 44. The information processing device 4 is a part that controls the driving of the sensor device 10, determines the detection component of the gas based on the change amount of the resonance frequency of the vibrator 16, and outputs the determination result.

[0031] The control unit 44 resonates the vibrator 16 by inputting a high-frequency signal of a predetermined frequency between the gate electrode 13 and the source electrode 14 of the sensor device 10. The acquisition unit 41 acquires a high-frequency signal (drain current) corresponding to the resonance frequency of the vibrator 16 from the drain electrode 15, and converts it into a change in the resonance frequency of the vibrator 16 based on the drain current. The determination unit 42 determines the type or concentration of the gas by referring to the resonance frequency information stored in the storage unit 6 based on a plurality of resonance frequency changes acquired by the acquisition unit 41. The output unit 43 outputs the determination result by the determination unit 42 to the display device 5.

[0032] When the gas to be detected is introduced into the accommodation chamber 20, the gas is adsorbed on the vibrator 16, so that the mass of the vibrator 16 changes, and based on the amount of change in the mass, the resonance frequency of the vibrator 16 decreases. Assuming that the mass of the vibrator 16 before gas adsorption is m, the amount of change in the mass of the vibrator 16 due to gas adsorption is Δm, and the resonance frequency of the vibrator 16 is f0, the amount of change in the resonance frequency Δf of the vibrator 16 is calculated by Equation (1). Δf = Δm × f0 / (2 × m) ···(1)

[0033] As shown in Equation (1), since the smaller the mass of the vibrator 16, the greater the change in the vibration frequency, it is preferable that the mass of the vibrator 16 is smaller. In the present embodiment, since the vibrator 16 is made of graphene having excellent electrical and mechanical properties and is made of carbon which is a light element, the change in the vibration frequency can be detected with high sensitivity.

[0034] The information processing device 4 acquires resonance frequency information for each of a plurality of different types of gases in advance and stores it in the storage unit 6. The determination unit 42 refers to the resonance frequency information stored in the storage unit 6 to identify and determine the type of gas detected by the sensor device 10. The output unit 43 outputs to the display device 5 the resonance frequency information acquired by the acquisition unit 41, and determination results such as the type and concentration of the gas determined by the determination unit 42.

[0035] The display device 5 has a display unit and displays the type and concentration of the gas output from the information processing device 4 on the display unit. The user can grasp the gas determination result by checking the display unit. The storage unit 6 acquires in advance the resonance frequency information for each of a plurality of known gases of different types detected by the gas determination system 1 and stores it as reference data. The storage unit 6 is composed of a storage device such as an HDD (Hard Disk Drive) or a semiconductor memory. The storage unit 6 may be on a cloud server to which the information processing device 4 can communicate, or may be provided in the information processing device 4.

[0036] [Details of the sensor device]

[0037] Subsequently, the details of the sensor device 10 will be described. FIG. 4 is a side cross-sectional view of the sensor device 10.

[0038] As described above, the vibrator 16 is disposed between the source electrode 14 and the drain electrode 15 so as to face the gate electrode 13. More specifically, the vibrator 16 has a first end portion 161 supported by the source electrode 14, a second end portion 162 supported by the drain electrode 15, and a vibrating portion 163 facing the gate electrode 13. The vibrator 16 is disposed at a predetermined gap (for example, 100 nm) in the thickness direction of the substrate 11 with respect to the gate electrode 13 so that the vibrating portion 163 can vibrate.

[0039] On the other hand, the source electrode 14 and the drain electrode 15 have a laminated structure of at least two conductor layers. That is, the source electrode 14 has a first source electrode layer 141 (first conductor layer) provided on the insulating film 12 and a second source electrode layer 142 (second conductor layer) provided on the first source electrode layer 141. The drain electrode 15 has a first drain electrode layer 151 (third conductor layer) provided on the insulating film 12 and a second drain electrode layer 152 (fourth conductor layer) provided on the first drain electrode layer 151.

[0040] The first end portion 161 of the vibrator 16 is disposed between the first source electrode layer 141 and the second source electrode layer 142 so as to be sandwiched therebetween. The second end portion 162 of the vibrator 16 is disposed between the first drain electrode layer 151 and the second drain electrode layer 152 so as to be sandwiched therebetween. The first source electrode layer 141 and the first drain electrode layer 151 are formed with a thickness greater than that of the gate electrode 13, so that the predetermined gap is formed between the vibrating portion 163 of the vibrator 16 and the gate electrode 13.

[0041] Thus, in the sensor device 10 of the present embodiment, since both ends of the vibrator 16 are supported so as to be respectively sandwiched between the conductor layers (electrode layers) constituting the source electrode 14 and the drain electrode 15, the vibrator 16 can be stably held. Therefore, it is difficult for the vibrator 16 to peel off, so that deterioration over time of the sensor device 10 can be suppressed and the durability can be improved. An adhesion layer such as chromium (Cr) that is in close contact with the first end portion 161 of the vibrator 16 may be provided between the first source electrode layer 141 and the second source electrode layer 142. Similarly, an adhesion layer such as Cr that is in close contact with the second end portion 162 of the vibrator 16 may be provided between the first drain electrode 151 and the second drain electrode 152. Thereby, since the adhesion between the vibrator 16 and the source electrode 14 and the drain electrode 15 is enhanced, the durability of the sensor device 10 can be improved.

[0042] The first source electrode layer 141 and the second source electrode layer 142 are preferably each composed of the same kind of metal material. Similarly, the first drain electrode layer 151 and the second drain electrode layer 152 are preferably each composed of the same kind of metal material. Thereby, generation of thermal stress at the interface of each electrode layer due to a difference in the coefficient of thermal expansion can be prevented, so that each end portion 161, 162 of the vibrator 16 can be supported more stably. The same kind of metal material means, in addition to the same metal material, an alloy material having the same main metal material.

[0043] FIG. 5 is a cross-sectional side view showing the configuration of the sensor device 110 according to the comparative example. In this sensor device 110, a source electrode 114 and a drain electrode 115 are formed on an insulating film 12 of a substrate 11, and a recess 120 for arranging a gate electrode 13 is formed in the insulating film 12 between the source electrode 114 and the drain electrode 115. The vibrator 116 is arranged in the recess 120 so as to face the gate electrode 13, and the upper surfaces of both ends of the vibrator 116 are respectively supported by the lower surfaces of the source electrode 114 and the drain electrode 115.

[0044] Here, the recess 120 is formed by a wet etching method using the source electrode 114 and the drain electrode 115 as masks. Since wet etching is isotropic etching, the recess 120 is accompanied by undercutting that erodes a part of the interface between the insulating film 12 and the source electrode 114 and the drain electrode 115. As a result, in the source electrode 114 and the drain electrode 115, a region not supported by the insulating film 12, which is the underlying layer, occurs in the vicinity of the end portions that support the vibrator 116. And a region not supported by the insulating film 12 also occurs in the vibrator 116, and only the upper surfaces of both end portions are supported by the source electrode 114 and the drain electrode 115. As a result, the rigidity of the portions supporting both end portions of the vibrator 116 is reduced, and the end portions of the source electrode 114 and the drain electrode 115 also vibrate as the vibrator 116 vibrates, making it difficult to vibrate the vibrator 116 in a desired vibration mode.

[0045] FIGS. 6(A) and (B) are simulation results of evaluating the vibration modes of the sensor device 110 according to the comparative example. FIG. 6(A) shows the primary vibration mode of the device with the sensor, and FIG. 6(B) shows the secondary vibration mode thereof. Here, the thickness of the source electrode 114 and the drain electrode 115 is 75 nm, the thickness of the insulating film 12 is 280 nm, the width of the source electrode 114 and the drain electrode 115 is 3 μm, the facing distance L1 (see FIG. 5) between the source electrode 114 and the drain electrode 115 is 1 μm, and the overhang length L2 (see FIG. 5) of the source electrode 114 and the drain electrode 115 to the recess 120 is 2 μm. In the example of this figure, the resonator 116 has two natural frequencies of 19.7 MHz and 20.2 MHz, and the respective Q values were 3080 for 19.7 MHz and 1509 for 20.2 MHz.

[0046] On the other hand, FIGS. 7(A) and (B) are simulation results evaluating the vibration modes of the sensor device 10 according to the present embodiment shown in FIG. 4. FIG. 7(A) shows the primary vibration mode of the device by the sensor, and FIG. 7(B) shows the secondary vibration mode thereof. Here, the thickness of the source electrode 14 and the drain electrode 15 is 150 nm (the respective thicknesses of the first source electrode layer 141, the second source electrode layer 142, the first drain electrode layer 151, and the second drain electrode layer 152 are 75 nm), the thickness of the insulating film 12 is 280 nm, the width of the source electrode 14 and the drain electrode 15 is 3 μm, and the facing distance between the source electrode 14 and the drain electrode 15 (the length of the vibrating portion 163 of the resonator 16) is 1 μm. In the example of this figure, the resonator 16 has two natural frequencies of 26.9 MHz and 77.6 MHz, and the respective Q values were 10008 for 26.9 MHz and 10009 for 77.6 MHz.

[0047] As is clear from the results of FIGS. 6 and 7, according to the present embodiment, a Q value of the resonator that is more than three times higher than that of the comparative example was obtained. The result in the comparative example is considered to be because the resonator was formed by under-etching of the insulating film 12, so the fixing was not sufficient, and the energy of the vibration dissipated to the outside, resulting in a decrease in the Q value of the resonator 116. On the other hand, in the present embodiment, both ends of the resonator 16 are sandwiched by the respective layers constituting the source electrode 14 and the drain electrode 15 and firmly fixed, so that the energy of the vibration does not dissipate to the outside, and it is considered that a high Q value was obtained. Thereby, according to the present embodiment, the gas responsiveness can be significantly improved as compared with the structure of the comparative example.

[0048] Furthermore, in the sensor device 110 of the comparative example, the difference between the two natural frequencies was small, showing values close to each other. This indicates that when one of them is selected as the main vibration mode for gas sensing, interference with the other vibration mode cannot be avoided. This is also caused by the source electrode 114 and the drain electrode 115 functioning as part of the vibrator 116, forming an unwanted vibration mode.

[0049] On the other hand, in the sensor device 10 of the present embodiment, the difference between the two natural frequencies is large. This means that when one vibration mode is used for gas sensing, the influence of the other vibration mode hardly appears, indicating that the generation of an extra vibration mode that may occur due to under-etching is suppressed.

[0050] [Method for manufacturing a sensor device] Subsequently, a method for manufacturing the sensor device 10 of the present embodiment configured as described above will be described.

[0051] First, as shown in FIG. 8(A), an insulating film 12 is formed on a substrate 11. Subsequently, as shown in FIG. 8(B), a first resist resin layer 101a is formed on the substrate 110, and a second resist resin layer 101b is formed thereon. For example, a methyl meth acrylate (MMA) film is used for the first resist resin layer 101a, and a poly methyl meth acrylate (PMMA) film is used for the second resist resin layer 101b.

[0052] Subsequently, as shown in FIG. 8(C), an electron beam lithography technique or the like is used to expose and develop the first resist resin layer 101a and the second resist resin layer 101b to form a resist pattern. In the present embodiment, an opening pattern is formed in which the pattern width of the second resist resin layer 101b is larger than the pattern width of the first resist resin layer 101a.

[0053] Subsequently, as shown in FIG. 8(D), a first metal layer 102a is formed on the surface of the second resist resin layer 101b and inside its opening. Thereafter, as shown in FIG. 8(E), the first and second resist resin layers 101a and 101b are removed to pattern (lift off) the first metal layer 102a, and a pattern of the first metal layer 102a is formed on the substrate 11.

[0054] The first metal layer 102a may be a single layer or may have a multilayer structure. In this embodiment, chromium (Cr) with a thickness of about 10 nm is formed as an adhesion material, and gold (Au) with a thickness of about 130 nm is formed thereon as an electrode material. The film formation method of the first metal layer 102a is not particularly limited either, and a sputtering method or a vacuum evaporation method may be used. In this embodiment, the first metal layer 102a is formed by an electron beam evaporation method. The first metal layer 102a corresponds to the first source electrode layer 141 and the first drain electrode layer 151 in the sensor device 10 shown in FIG. 2.

[0055] Subsequently, as shown in FIG. 9(A), a third resist resin layer 103a is formed on the substrate 11, and a fourth resist resin layer 103b is formed thereon. For example, a methyl meth acrylate (MMA) film is used for the third resist resin layer 103a, and a poly methyl meth acrylate (PMMA) film is used for the fourth resist resin layer 103b.

[0056] Subsequently, as shown in FIG. 9(B), an electron beam lithography technique or the like is used to expose and develop the third resist resin layer 103a and the fourth resist resin layer 103b to form a resist pattern. In this embodiment, an opening pattern is formed in which the opening width of the third resist resin layer 103a is larger than the opening width of the fourth resist resin layer 103b.

[0057] Subsequently, as shown in FIG. 9(C), a second metal layer 102b is formed on the surface of the fourth resist resin layer 103b and inside its opening, and then a sacrificial layer 104 is formed on the surface of the second metal layer 102b. The sacrificial layer 104 is composed of, for example, a resist resin.

[0058] Thereafter, as shown in FIGS. 9(D) and 10(A), the third and fourth resist resin layers 103a, 103b and the second metal layer 102b formed on the fourth resist resin layer 103b are removed to pattern (lift-off) the second metal layer 102b and the sacrificial layer 104 formed on the second metal layer 102b, and a pattern of the second metal layer 102b and the sacrificial layer 104 is formed on the substrate 11.

[0059] The second metal layer 102b may be a single layer or a multilayer structure. In this embodiment, chromium (Cr) with a thickness of about 10 nm is formed as an adhesion material, and gold (Au) with a thickness of about 30 nm is formed thereon as an electrode material. The film formation method of the second metal layer 102b is not particularly limited, and may be a sputtering method or a vacuum evaporation method. In this embodiment, the second metal layer 102b is formed by an electron beam evaporation method.

[0060] The second metal layer 102b corresponds to the gate electrode 13 in the sensor device 10 shown in FIG. 2. Also, the stacked thickness of the second metal layer 102b and the sacrificial layer 104 is typically made the same as the thickness of the first metal layer 102a. In this embodiment, since the opening width of the third resist resin layer 103a is larger than the opening width of the fourth resist resin layer 103b, the second metal layer 102b is less likely to contact the side surface of the opening of the third resist resin layer 103a, thereby improving the patterning accuracy of the second metal layer 102b during lift-off.

[0061] Thereafter, as shown in FIG. 10(B), a laminate of the graphene layer 105 and the protective layer 106 is transferred to the first metal layer 102a. The protective layer 106 is composed of, for example, a resist resin. Thereafter, as shown in FIG. 10(C), the protective layer 106 is removed. The graphene layer 105 corresponds to the vibrator 16 in the sensor device 10 of FIG. 2.

[0062] Subsequently, as shown in FIG. 10(D), a third metal layer 102c is formed over the first metal layer 102a. As a method for forming the third metal layer 102c, for example, after forming a resist pattern over the graphene layer 105, the third metal layer 102c is formed, and then the resist pattern is removed to pattern the third metal layer 102c (lift-off).

[0063]

[0062] The third metal layer 102c faces the first metal layer 102a with the graphene layer 105 therebetween. The shape of the third metal layer 102c is not particularly limited, and in the present embodiment, it is formed with an area smaller than that of the first metal layer 102a. The third metal layer 102c corresponds to the second source electrode 142 and the second drain electrode 152 in the sensor device 10 of FIG. 2.

[0064] Subsequently, as shown in FIG. 10(E), a fifth resist resin layer 107a is formed over the graphene layer 105 and the third metal layer 102c, and a sixth resist resin layer 107b is formed thereover. For example, a polymethyl methacrylate (PMMA) film is used for the fifth resist resin layer 107a, and for example, an AR-N film is used for the sixth resist resin layer 107b.

[0065] Subsequently, as shown in FIG. 10(F), a resist pattern is formed by exposing and developing only the sixth resist resin layer 107b using an electron beam lithography technique or the like.

[0066]

[0063] Subsequently, as shown in FIG. 11(A), the fifth resist resin layer 107a and the graphene layer 105 not covered by the sixth resist resin layer 107b are removed by dry etching. For example, O2 plasma is used as the dry etching method. Subsequently, as shown in FIG. 11(B), the fifth and sixth resist resin layers 107a and 107b are removed, and as shown in FIG. 11(C), the sacrificial layer 104 is removed.

[0067] As described above, the embodiments of the present invention have been explained. However, the present invention is not limited to the above-described embodiments only, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[0068] For example, in the above embodiments, the sensor device 10 having a bottom gate structure in which the gate electrode 13 is disposed between the insulating film 12 of the substrate 11 and the vibrator 16 has been described as an example. However, the present invention is not limited thereto, and the present invention is also applicable to a sensor device having a top gate structure in which the gate electrode is located directly above the vibrator.

Explanation of Reference Numerals

[0069] 1... Gas determination system 4... Information processing device 10... Sensor device 11... Substrate 12... Insulating film 13... Gate electrode 14... Source electrode 15... Drain electrode 16... Vibrator 141... First source electrode (first conductor layer) 142... Second source electrode (second conductor layer) 151... First drain electrode (third conductor layer) 152... Second drain electrode (fourth conductor layer) 161... First end 162... Second end 163... Vibrating portion

Claims

1. A substrate, an insulating film formed on the substrate, a gate electrode disposed on the insulating film, a first conductor layer and a second conductor layer provided on the first conductor layer, and a source electrode disposed on the insulating film, a third conductor layer and a fourth conductor layer provided on the third conductor layer, and a drain electrode disposed on the insulating film, a first end portion sandwiched between the first and second conductor layers, a second end portion sandwiched between the third and fourth conductor layers, and a vibrator having a vibrating portion facing the gate electrode with a predetermined gap in the thickness direction of the substrate, comprising: the gate electrode is disposed between the source electrode and the drain electrode, and the first conductor layer and the third conductor layer have a thickness greater than that of the gate electrode a sensor device.

2. The sensor device according to claim 1, wherein the vibrator includes a graphene layer a sensor device.

3. The sensor device according to claim 2, wherein the vibrator further includes a sensitive film formed on the graphene layer a sensor device.

4. The sensor device according to claim 3, wherein the sensitive film is a porous film a sensor device.

5. The sensor device according to claim 4, wherein the porous film is a carbon-based material a sensor device.

6. The sensor device according to any one of claims 1 to 5, wherein the first to fourth conductor layers are made of the same kind of metal material a sensor device.

7. The sensor device according to any one of claims 1 to 6, wherein the source electrode is disposed between the first and second conductor layers and further has an adhesion layer that is in close contact with the vibrator, and the drain electrode is disposed between the third and fourth conductor layers and further has an adhesion layer that is in close contact with the vibrator a sensor device.

8. The sensor device according to any one of claims 1 to 6, wherein the gate electrode is disposed between the substrate and the vibrator a sensor device.

9. Form a lower electrode layer on the substrate, form a graphene layer on the lower electrode layer, form an upper electrode layer on the graphene layer, By patterning the lower electrode layer and the upper electrode layer, a source electrode that supports one end of the graphene layer so that the graphene layer can vibrate, a drain electrode that supports the other end of the graphene layer so that the graphene layer can vibrate, and a gate electrode that faces the graphene layer with a predetermined gap in the thickness direction of the substrate are respectively formed. The gate electrode is disposed between the source electrode and the drain electrode, and a part of the source electrode and a part of the drain electrode located between the substrate and the graphene layer are formed to have a thickness larger than that of the gate electrode. A method of manufacturing a sensor device.

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