JPH0933467A - Mosfet-type gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a MOSFET-type gas sensor the size of a gas introduction port of which can be changed thereby to adjust a sensitivity in accordance with a concentration range of a gas, improve a selectivity to gases and correct a characteristic change due to influences by an external field. SOLUTION: The sensor is provided with a gate electrode 10 and a gate insulation film 13. A slit or hole 11 is formed in the gate electrode 10 allowing a predetermined gas to pass through. The gas passing through the slit or hole 11 comes directly or indirectly in touch with the insulation film 13. A predetermined gap 12 is formed between the gate electrode 10 and gate insulation film 13. The gap 12 is divided to a plurality of compartments by diaphragms not passing the gas. At least one or more of the plurality of compartments or, one or more slits or holes 11 of the compartments are covered with a member not passing the gas. A sensitivity of the sensor can thus be adjusted in accordance with a target concentration range of the gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FET gas sensor, and more particularly to a gas sensor capable of adjusting the sensitivity, selectivity or responsiveness of the sensor according to an external electric signal or an external condition such as temperature.

[0002]

2. Description of the Related Art A semiconductor gas sensor for detecting leaked gas, measuring concentration, or analyzing a sampled gas has a MOSFET gas sensor having a structure shown in FIG. 8 as a sensor suitable for the purpose. . That is,
In the structure of this MOSFET, for example, a structure having a gap for introducing gas on the gate insulating film and a slit or hole in the gate electrode for introducing gas is described in Appl.
Proposed in ied Physics Letters Vol.43, P.700 1983.

Further, Japanese Patent Application Laid-Open No. 3-274452 proposes a "field effect transistor type oxygen sensor", which is a FET type sensor and has a gate electrode film and a solid electrolyte film and has high responsiveness. High sensitivity is achieved.

[0004]

However, in the conventional sensor as described above, the size of a large number of slits or holes for introducing gas provided in the gate electrode is constant, so that the object is to be detected. In order to cover and measure the concentration range of various gases, there is an operational problem that a large number of sensors must be prepared for all kinds of gases. Therefore, there is a problem that the advantage of being a sensor capable of cost reduction by mass production as the FET gas sensor cannot be fully utilized.

Further, the conventional sensor also has a problem that an output error occurs due to the temperature characteristic of the sensor depending on the use environment. Therefore, the main object of the present invention was made in view of the above problems, by changing the size of the slits or holes depending on the external signal, such as a signal from the outside, or the temperature. ,
A MOSFET capable of adjusting the sensor concentration according to the target gas concentration range, improving the selectivity for the target gas, and appropriately correcting the characteristic change of the sensor due to the influence of the external environment such as temperature. Type gas sensor.

[0006]

Therefore, the present invention takes the following means in order to solve the above problems. That is, in the FET gas sensor, in order to adjust the sensitivity of the sensor by adjusting the size of the slit or hole,
Mass production by arranging multiple compartments that are divided by partition walls in units with different sizes of slits or holes in advance and closing unnecessary compartments for detection depending on the target gas concentration range when detecting gas, etc. As a result, it becomes possible to properly operate a predetermined one sensor from a large number of inexpensively manufactured sensors according to the target gas concentration range.

Further, the size of the slit or hole is required by appropriately adopting a material such as "electricity" or "light" which changes its shape in response to a signal given from the outside of the sensor to form the slit or hole. It is also possible to change it at any time to optimally adjust the sensor sensitivity.

Further, depending on the size of the slits or holes, it is possible to permeate only the target gas molecules and improve the selectivity. In addition, by forming slits or holes using a material that changes shape according to the external environment such as temperature, it is possible to correct the detection error caused by the change in the sensor characteristics depending on the state of the external environment. It is possible.

(Function) By variably adjusting the size of the gas introducing slit or hole of the gas sensor according to the structure or material forming the gas introducing slit or hole and the combination thereof, a gate insulating film disposed inside the slit is formed. The amount or type of gas molecules that come into direct or indirect contact can be appropriately adjusted as desired, so that the sensitivity or selectivity as a gas sensor is adjusted or corrected according to its application and need.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of embodiments of the present invention will be sequentially described below with reference to the drawings. (Embodiment 1) FIGS. 1A to 1C show the structure of a MOSFET sensor as one embodiment of the present invention. More specifically, FIG. 1A is a plan view of the FET gas sensor, FIG. 1B is a vertical cross-sectional view taken along line AA in the plan view, and FIG. 1C is the same plan view. Line segment BB
A vertical sectional view at is shown.

On the surface of the MOSFET sensor shown in FIG. 1 (a), the MOSFET which constitutes this MOSFET sensor is formed.
It can be seen that many slits or holes 11 are formed in the gate electrode 10 of T for introducing gas, and the densities of the formed arrays are different.

In this way, the FET gas sensor composed of a plurality of compartments 21 to 22 having different array densities has a partition wall 21 for partitioning the array density into three groups for gas introduction. Two
It is divided into 2, 23.

As can be seen from FIGS. 1 (b) and 1 (c), under the layer in which the slits 11 are formed, for example, a silicon oxide film layer made of a material that can be processed by etching or the like is formed in the middle. It is formed as a layer and forms a partition of the compartment. A space having a predetermined depth (the thickness of the intermediate layer in the figure) is formed by etching or the like as a "void" 12 over a predetermined range of a part of the intermediate layer. The gate insulating film 13 is partially exposed at the bottom of this space.

Of the three compartments described above, the compartment 21 with the coarsest array density is used for the "high" gas concentration, while the compartment 23 with the dense array density is the "low" gas concentration. Can be used for.

Further, since the slits or holes of the compartment having a density not adapted to the gas to be detected are not used, they may be closed if desired. The feature of the first embodiment of the present invention is that a plurality of compartments 21 to 23 having different densities of slits or holes 11 formed for gas introduction are formed in the gate electrode, and slits not used as needed. Alternatively, it is characterized in that the hole 11 is “closed” with a material such as an adhesive tape or a resin that blocks a target gas.

The MO of the first embodiment having such characteristics
When operating the SFET sensor, for example, when it is desired to measure an extremely low concentration gas with high sensitivity, the SFET sensor is used with all slits or holes opened. On the other hand, for example,
If you want to measure a high concentration gas over a wider concentration range so that the concentration and sensor output remain linear, you can use one or more compartments blocked by the means described above. Good.

The manufacturing of the structure of the sensor as shown in the drawings is described in, for example, Applied Physics Letters Vol.43, P.7.
It can be easily formed by the manufacturing process generally used in the semiconductor forming process described in 00 1983. Also,
It is also possible to use the same dimensions as the normal MOSFET, such as the gate length.

(Operation and Effect 1) As described above, according to the first embodiment, the sensitivity of the sensor can be adjusted. In addition, by preparing multiple compartments with different slit or hole densities, even if compared to the conventional sensor in which multiple compartments with the same slit or hole density are prepared by combining them, the sensitivity becomes even finer in operation. Adjustment is also possible on the user side.

(Embodiment 2) In Embodiment 1 described above, the void 12 is provided on the gate insulating film 13. However, in the present embodiment, other than that, the void is not provided as shown in FIG. Is also possible.

That is, as shown in the figure, the gate electrode 1 in which the slits or holes 11 are formed with a predetermined array density.
There is a laminated structure in which the gate insulating film 13 is superposed immediately below 0, and it can be seen that the structure of the semiconductor sensor has "no void" different from the previous example.

(Effect 2) According to the present embodiment, a MOSFET type sensor which exhibits the same effect as that of the previous example as a semiconductor sensor without forming a gap between the gate electrode 11 and the gate insulating film 13 as in this example. It can be easily manufactured and provided at a lower cost.

(Embodiment 3) In Embodiment 1 described above, the sensitivity adjustment as a gas sensor is made possible by changing the arrangement density of the slits or holes 11; Also, not only the size or shape of the slit or hole 11 as shown in FIG. 3A, but also the “depth” of the void as shown in FIG. It is shown that.

That is, as shown in FIG.
In the gate electrode 10 on the surface of the SFET sensor, a large number of slits or holes 11 having slightly different "sizes" or "shapes" of openings for gas introduction are formed, and the density of the formed array is also a compartment. It is different for each (indicated by the broken line).

The size of the slit or hole for introducing the gas is arbitrarily set according to the object to be detected.
Further, the shape of the opening is not limited to the “rectangle” in the previous example, and may be a circle, an ellipse, or a triangle, and an optimum shape or size for a detection target or environment may be selectively used.

Further, as shown in the sectional view of FIG.
The voids 12 of the three types of compartments are different from each other, and show a structure in which the depth is formed in three stages from "shallow" to "deep".

Thus, the "depth" of the void, that is, the void 1
The same effect as described above can be obtained by changing the "volume" of 2 for each compartment. (Function and Effect 3) The presence of the gas molecules is detected by coming into contact with the gate insulating film 13 arranged at the bottom of the void 12 or the upper thin film thereof made of, for example, a silicon oxide film or the like. However, since the voltage change is usually larger in the state where the gate insulating film 13 is in direct contact with the gate insulating film 13, the detection can be performed with high sensitivity.

Regarding the linearity of the voltage change, the linearity is better when the oxide thin film described above is interposed between the gas molecules and the gate insulating film 13 than the direct contact as described above.

Regarding the "volume" of the void 12, the larger the volume, the slower the response of the sensor. Therefore,
When a quick response characteristic is required, it is preferable to use a compartment having a structure in which the void 12 has a small volume.

Similarly, the "distance" between the void 12 and the insulating film 13 also affects the response of the sensor, until the gas molecules pass through the slit of the gate electrode 10 and reach the gate insulating film 13 or the adjacent oxide film. Inversely proportional to the time of.

Therefore, in this embodiment, the gap 12 is simply
The effect of changing the "distance" between the void 12 and the gate insulating film 13 and the effect of changing the thickness of the intervening oxide thin film are added in addition to the effect of changing the volume of the gate insulating film.

(Embodiment 4) As shown in FIGS. 4 (a) and 4 (b), the gate electrode 10 is made of a material that changes its shape in response to an external signal, so that gas is introduced by an external signal. A sensor for adjusting the size of the slit or hole 11 for use as a result, and as a result, adjusting the sensitivity of the gas sensor is illustrated as the fourth embodiment.

As the material of the gate electrode 10, other than the material having conductivity itself, a metal film is formed on the surface of the material which is deformed as described above, or a conductive material is dispersed in the material. But it is possible.

As a specific example of a material which changes its shape in response to an external signal, a piezoelectric material (for example, PZT or PVDF) is used when the external signal is an electric signal. In this case, in order to apply an electric signal to the material, it is necessary to form an electrode on the material (not shown). As an example of the structure, there is a laminated structure called “unimorph” in which electrodes for voltage application are formed on both sides of a piezoelectric material, that is, a structure in which a certain piezoelectric material is sandwiched between two metal layers from both sides is adopted. . Furthermore, as an example of a structure for increasing the amount of deformation, a laminated structure called "bimorph" similar to the above-mentioned "unimorph" having two layers, that is, a metal layer, a piezoelectric material,
There is one that adopts a five-layer structure of a metal layer, a piezoelectric material, and a metal layer. Although such a structure causes a slight increase in cost due to a slightly complicated production process, it is a structure capable of further increasing the amount of deformation.

(Function and Effect 4) In the enlarged cross section of the gate electrode 10 shown in FIG. 5A, the upper piezoelectric material layer,
When voltages having different polarities are applied to the lower piezoelectric material layers, the layers bend as shown in FIG. 5B, so that the slits 11 expand and gas molecules to be detected easily enter. As a result, The sensor sensitivity is improved.

Next, when the external signal is "light", an inorganic pyroelectric material or a polymer material formed of molecules that undergo structural change by light is used. Also, the external signal is "heat"
In this case, a material having a large coefficient of thermal expansion, a shape memory alloy, a bimetal, or the like is used.

As shown in FIGS. 6 (a) and 6 (b), when a shape memory alloy is used, the slits or holes are usually closed, and the slits or holes are set to open at a certain temperature or higher. It is possible to detect the gas or measure the concentration.

If a bimetal having a structure similar to that described above is used instead of the shape memory alloy, the size of the slit or the hole 11 continuously changes due to the temperature change, so that the characteristics of the sensor change depending on the temperature. It is possible to correct this.

The temperature correction coefficient can be adjusted by optimizing the material of the bimetal used, the size of the slit or hole, or the width of the slit as a sensor.

In this embodiment, the void 1 is formed on the gate insulating film 13.
2 is an example in which it is provided, but it is also possible to implement a structure having no gap as shown in FIG.

(Embodiment 5) The above-mentioned (Embodiment 4)
It is also possible to use the slits or holes 11 shown in 1 as means for selectively permeating gas molecules to be measured. That is, it is possible to selectively permeate gas molecules having a small molecular diameter such as hydrogen by narrowing the voids, and improve the selectivity for molecules other than the measurement target.

Further, the slit width is set to r by an external signal.
By changing from 1 to r2 (r1 <r2) and taking the difference between the sensor outputs before and after that, the molecules with the size range of the diameter r of the molecule are selectively detected such that r1 <r <r2. It is also possible to do so. Since the deformation of the piezoelectric material is caused by the distortion of the crystal structure due to the application of voltage, the deformation amount is extremely small and can be controlled at the nanometer level. Therefore, if a piezoelectric material is used to change the width of the slit, it is possible to select only the desired molecule due to the minute difference in molecular diameter as described above.

(Function and effect 5) The diameter of the slit (hole) is r1.
In the case of, a molecule having a molecular diameter r1 <r cannot pass through the slit, but the sensor output at this time is assumed to be S1.
Next, by changing the diameter of the slit (hole) to r2 (where r1 <r2) by an external signal, r <r2
Molecules having a molecular diameter of Assuming that the sensor output at this time is S2, the difference between the respective sensor outputs, S2-S1, is such that the molecular diameter r is proportional to the concentration of molecules in the range of r1 <r <r2.

Therefore, even when detecting a hydrogen gas having a small diameter and a nitrogen gas having a relatively large diameter, the gas to be detected is changed by changing the diameter of the slit in consideration of their actual diameters. Only the desired type of gas can be selectively detected or excluded from the sensor based on the size of the molecule.

(Embodiment 6) As shown in FIG. 7A, the materials of the gas sensitive films 30 to 32 are formed in different structures in each compartment. Specifically, the first gas sensitive membrane 30 is laid in the bottom of the void 12 in the first compartment, and the second gas sensitive membrane 31 is placed in the bottom of the void 12 in the second compartment adjacent to the first gas sensitive membrane 30. A third gas sensitive membrane 32 is likewise laid at the bottom of the void 12 in the other adjacent third compartment.

In the sensor having such a structure, only the compartment in which the gas sensitive film sensitive to the gas to be detected is arranged may be selectively used, which is desired as shown in FIGS. 7 (b) and 7 (c). Slit 1 for compartment only
Only one needs to be opened.

(Function and Effect 6) In other words, according to such a structure, it is not necessary to form a measuring circuit for each sensor having different materials for the gas sensitive films 30 to 32, and a common measuring circuit and an external signal are transmitted. The sensor can be configured with the mechanism that operates.

Furthermore, when light, heat, etc. is used as the external signal, it is not necessary to make direct contact with the sensor, so the structure of the sensor can be made simpler than when an electrical signal is used as the external signal. You can

Although the present embodiment is an example in which the void 12 is provided on the gate insulating film, in addition to this, the structure in which the void 12 is not provided as shown in FIG. It goes without saying that it is also possible.

Further, a desired gas introduction slit or hole 1 is provided in each compartment shown in FIGS. 7 (b) and 7 (c).
As a method of opening and closing 1, in addition to the above, an electrode (not shown) that selectively applies a voltage of a predetermined polarity is provided in each compartment unit, and the desired slit diameter is controlled by electrical ON / OFF control. You may change it.

(Embodiment 7) The above-mentioned (Embodiment 4)
In the above, the size of the slits or holes for introducing gas is changed by the deformation of the material itself. However, a plurality of slits or holes having a certain size are combined to form the MOSFE of the present invention.
A T-type sensor may be implemented.

(Effect 7) As a result, by appropriately combining the magnitudes of these limiting conditions and moving the slit arrangement positions relatively in correspondence with the detection gas,
It is also possible to change the size of the slit or hole for introducing a desired gas, and it is possible to take advantage of the MOSFET type sensor that can exert the same effect as described above easily and in mass production at low cost. It will be possible.

As means for relatively moving the plurality of slits or holes, for example, "micromachine technology" is used.
, "Mechanical Design," Vol. 35,
The method using an electrostatic motor in No. 14, P. 35, 1991 can also be applied.

Although the present invention has been described above based on a plurality of embodiments, the scope of the present invention is included in the present specification. (1) In a gas sensor using MOSFET,
A partition (wall) that has a surface (for example, a gate insulating film) for contacting the gate insulating film with a predetermined gas or a predetermined space between them and the surface or the space does not allow gas to pass therethrough. A structure having a compartment divided into a plurality by, and having a slit or a hole in the gate electrode for introducing the gas into the surface or the void, of the surface or the void divided into a plurality of By closing one or more of them or one or more of the slits or holes associated therewith with a member that does not permeate the gas to be detected, the sensor sensitivity can be adjusted according to the target gas concentration range. It is characterized by

(2) In a gas sensor using a MOSFET, the gate electrode has a surface or a space for contacting a predetermined gas with the gas, and a predetermined gate electrode for introducing the gas into the surface or the space. Has a slit or a hole, and the "size" of the slit or the hole
Is a MOSFET type gas sensor in which the sensor sensitivity can be adjusted in accordance with a desired desired gas concentration range by changing according to a signal from the outside or a state of the external environment.

(3) The MOSFET gas sensor according to (2), characterized in that it is possible to improve the selectivity with respect to the gas to be measured by setting the size of the slit or the gap. .

(4) In a gas sensor using a MOSFET, the gate insulating film has a surface or a space for contacting a predetermined gas, and a slit or a gate electrode for introducing the gas into the surface or the space. MOSFET type characterized by having a hole, and by changing the "size" of the slit or hole according to the state of the outside world, it is possible to correct the change in the characteristics of the sensor depending on the state of the outside world. It is a gas sensor.

(5) In a gas sensor using a MOSFET, the gate insulating film has a surface or a space for contacting the gas, and the surface or the space is divided into a plurality of "divisions" that do not allow a predetermined gas to pass therethrough. Has a space structure (compartment) formed therein and has a slit or a hole in the gate electrode for introducing the gas into the surface or void of interest, and has a slit or a hole on the gate insulating film for each surface or void of the compartment. It is a MOSFET type gas sensor characterized in that the gas sensitive film material is different, and the slits or holes on the gate electrode associated with individual voids are opened and closed according to a signal from the outside or the state of the outside world.

(6) In a gas sensor using a MOSFET, it has a surface or void for contacting the gate insulating film with the gas, and a slit or hole in the gate electrode for introducing gas into the surface or void. The MOSFET type gas sensor is characterized in that the sensor sensitivity can be adjusted according to a target gas concentration range by changing the slit or the hole by a device driven by an external signal.

(7) A MOSFET gas sensor characterized in that, in addition to the structure shown in the above-mentioned embodiment in which a gap is provided on the gate insulating film, a structure in which no gap is provided is provided. That is, this is a "void-free" laminated structure in which a gate insulating film is superposed immediately below a gate electrode in which slits are formed with a predetermined array density.

[0060]

As described above, the MOS of the present invention
According to the plurality of embodiments of the FET gas sensor and the gist described in the claims, the following effects can be obtained. 1. According to the essence (1) of the present invention, it is possible to appropriately adjust the sensor sensitivity according to the application by using a simple post-treatment on a MOSFET gas sensor mass-produced in advance. Furthermore, if the slit is closed by a detachable member, it can be reused even when it is desired to use with different sensitivity. As a result, it is possible to provide a cheaper MOSFET gas sensor with a wider range of use.

2. According to the gist (2) of the present invention, since the sensitivity of the gas sensor can be adjusted by a signal from the outside world,
The sensitivity of the sensor can be continuously adjusted as needed.
Therefore, it is also possible to adjust so as to obtain optimum sensitivity according to the gas concentration to be measured. Further, when the measurement is unnecessary, the contact between the gas and the sensor sensitive film is cut off, so that the life of the sensor sensitive film can be extended. Further, if light, heat or the like is used as a signal from the outside, there is an effect that an electric circuit for control becomes unnecessary.

3. According to the essence (3) of the present invention, by changing the width of the gas permeation slit or the size of the hole according to the size of the gas molecule to be measured by the signal from the outside or the state of the external environment. There is an effect that the selectivity with respect to the gas molecule to be measured can be enhanced.

4. According to the gist (4) of the present invention, even if the characteristics of the gas sensor itself change due to the state of the outside world, there is an effect that an electric circuit or the like for correcting the characteristic becomes unnecessary.

5. According to the essence (5) of the present invention, a sensitive film that responds to a plurality of gases is formed in one sensor, and they are turned on and off depending on a signal from the outside or a state of the outside world.
The effect of F is that there is no need for extra circuits and the like as compared with the case where a plurality of sensors are driven by individual circuits.

6. According to the essence (6) of the present invention, there is an effect that the sensor sensitivity can be changed more greatly by changing the width of the slit and the size of the hole using a means such as an electrostatic motor.

7. According to the gist (7) of the present invention, a MOSF that exhibits the same effect as a semiconductor sensor without forming a gap between the gate electrode and the gate insulating film.
There is an effect that the ET sensor can be easily manufactured and provided at a lower cost.

[Brief description of the drawings]

FIG. 1 shows a configuration as a first embodiment of the present invention,
(A) is a plan view showing the arrangement structure of the compartments having a change in density, (b) is a longitudinal sectional view taken along line AA in (a), and (c) is a line segment in (a). The longitudinal cross-sectional view in BB.

FIG. 2 is a cross-sectional view showing a structure as a second embodiment of the present invention and having a structure without voids.

FIG. 3 shows a configuration as a third embodiment of the present invention,
(A) is a plan view showing an array structure of compartments having a volume change, (b) is a cross-sectional view taken along line AA in (a).

FIG. 4 shows a configuration as a fourth embodiment of the present invention,
9A is a cross-sectional view of a material whose shape is changed by an external signal before the deformation, and FIG. 9B is a cross-sectional view after the deformation.

FIG. 5 shows a configuration as a fourth embodiment of the present invention,
(A) is a cross-sectional view of the bimorph structure before deformation, (b)
Is a cross-sectional view after the deformation.

FIG. 6 shows a configuration as a fourth embodiment of the present invention,
(A) is a cross-sectional view of the bimetal or shape memory alloy before deformation, and (b) is a cross-sectional view after the deformation.

FIG. 7 shows a configuration as a sixth embodiment of the present invention,
(A) is a cross-sectional view of a structure in which a material is different for each compartment before deformation, (b) is a cross-sectional view of the material after deformation,
FIG. 6C is a sectional view after the deformation.

FIG. 8 is a sectional view showing the structure of a conventional MOSFET type gas sensor.

[Explanation of symbols]

 10 ... Gate electrode, 11 ... Slit or hole, 12 ... Void, 13 ... Gate insulating film, 21-23 ... Compartment, 30-32 ... Gas sensitive film.

Claims (7)

[Claims] 1. A gate electrode having a slit or a hole through which a predetermined gas can pass, and a gate insulating film with which the gas passing through the slit or the hole comes into indirect or direct contact. A predetermined gap is formed between the gate electrode and the gate insulating film, and the gap has a structure divided into a plurality of compartments by a partition wall that does not permeate the gas, and at least one of the plurality of compartments is formed. One or at least one of the slit or the hole associated with the compartment is configured to be occludable by a member that does not permeate the gas, and the sensor sensitivity is selectively selected according to a desired desired gas concentration range. A MOSFET type gas sensor characterized by being configured to be adjustable. 2. A gate electrode formed by forming a slit or a hole through which a predetermined gas can pass, and a gate insulating film with which the gas passing through the slit or the hole comes into indirect or direct contact. A structure in which a predetermined gap is formed between the gate electrode and the gate insulating film is formed, and the “size” of the slit or hole is changed according to a predetermined signal from the outside or the state of the external environment. By doing so, the MOSFET type gas sensor is configured so that the sensor sensitivity can be adjusted according to the desired predetermined gas concentration range. 3. The setting of the size of the slit or the gap makes it possible to improve the selectivity with respect to the gas to be measured.
MOSFET type gas sensor described in 1. 4. A gate electrode formed with a slit or a hole through which a predetermined gas can pass, and a gate insulating film with which the gas passing through the slit or the hole comes into indirect or direct contact. A predetermined gap is formed between the gate electrode and the gate insulating film, and the size of the slit or the hole is changed according to the state of the outside world to change the characteristics of the sensor depending on the outside state. MOSFE characterized by enabling correction
T-type gas sensor. 5. A gate electrode having a slit or a hole through which a predetermined gas can pass, and a gate insulating film with which the gas passing through the slit or the hole comes into indirect or direct contact. A predetermined gap is formed between the gate electrode and the gate insulating film, and the gap forms a structure divided into a plurality of compartments by a partition wall that does not permeate the gas, and an inner surface of each compartment or Gas sensitive film materials having different kinds of sensitive gases are arranged in the voids, and the slits or holes on the gate electrode, which are associated with the respective voids, are formed on the basis of a signal from the outside or a state of the outside world. MOS characterized by being openable and closable
FET type gas sensor. 6. A gate electrode formed with a slit or a hole through which a predetermined gas can pass, and a gate insulating film with which the gas passing through the slit or the hole comes into indirect or direct contact. A predetermined gap is formed between the gate electrode and the gate insulating film, and the slit or the hole is changed by a device that is driven by a predetermined signal from the outside, so that a desired gas concentration range can be obtained. A MOSFET type gas sensor characterized in that the sensor sensitivity is adjustable by means of a gas sensor. 7. A gate electrode formed with a slit or a hole through which a predetermined gas can pass, and a gate insulating film with which the gas passing through the slit or the hole comes into indirect or direct contact. By changing the size of the slit or the hole according to the state of the external environment, it is possible to correct the change in the characteristic of the sensor depending on the state of the external environment.
T-type gas sensor.