Controllable extraction structure for 3T1C gas response internal characteristics

Abstract

The invention discloses a 3T1C gas response internal characteristic controllable extraction structure, which belongs to the technical field of gas sensors, and specifically comprises an N-type gas sensitive field effect transistor, a P-type gas sensitive field effect transistor, an output modulation field effect transistor and a fixed capacitor, the N-type gas-sensitive field effect transistor is connected with the source electrode of the P-type gas-sensitive field effect transistor, and is connected to a signal output end through the fixed capacitor; the drain electrode of the N-type gas sensitive field effect transistor is connected with a driving voltage; the grid electrode of the output modulation field effect transistor is connected with modulation voltage, one of the source electrode and the drain electrode is connected with a signal output end, and the other one and the drain electrode of the P-type gas sensitive field effect transistor are jointly connected with a common ground end. Conversion and amplification of target gas concentration response are realized by utilizing the influence effect of target gas on channel resistance of different types of gas sensitive field-effect tubes, and ultrafast extraction and controllable modulation of gas concentration characteristics are realized by outputting a time constant of a modulation field-effect tube control differentiating circuit. The system has the advantages of easy integration, low power consumption and ultrafast response.

Description

Technical Field

[0001] This invention belongs to the field of gas sensor technology, specifically relating to a controllable extraction structure for the internal features of a 3T1C gas response sensor. Background Technology

[0002] With the acceleration of modern industrialization and the increasing demands for quality of life, gas detection technology plays an irreplaceable role in many fields such as environmental monitoring, industrial production safety, medical and health diagnosis, and the Internet of Things (IoT). Therefore, designing technologies capable of rapidly and accurately detecting the concentration of target gases in real time has become a focus of attention for both academia and industry.

[0003] Currently, there are many types of gas sensors available, which, based on their detection principles, mainly include electrochemical, infrared optical, catalytic combustion, surface acoustic wave, and resistive gas sensors. Among them, resistive gas sensors, with their significant advantages such as high sensitivity, relatively fast response speed, simple structure, low cost, and ease of miniaturization and integration, have shown great application potential in portable devices and large-scale sensor networks, and are considered one of the important directions for the future development of gas detection technology.

[0004] However, traditional resistive semiconductor gas sensors still face significant technical bottlenecks in practical applications, primarily manifested in their long response times. These sensors typically operate based on the adsorption and desorption of gas molecules on the surface of a sensitive material, characterizing gas concentration through changes in material resistance caused by charge transfer. This physicochemical process often requires a considerable amount of time to reach thermodynamic equilibrium; that is, the sensor can only accurately output gas concentration information after its resistance stabilizes. In scenarios involving sudden gas leaks or requiring transient responses, this time lag due to the need to wait for "adsorption equilibrium" severely limits their effectiveness.

[0005] Therefore, in order to solve the problem that the gas response speed is limited by the adsorption equilibrium time in the existing technology, it is urgent to propose a new sensor structure or detection mechanism that can quickly extract and output gas concentration information without waiting for the adsorption equilibrium process. This has important practical value for improving the real-time monitoring capability of gas sensors. Summary of the Invention

[0006] To address the problem that the gas response speed in the prior art is limited by the adsorption equilibrium time, this invention provides a 3T1C gas response sensor feature controllable extraction structure, which is used to improve the output speed of the concentration feature of the gas sensor and realize the controllability of the signal output time and amplitude. It has the advantages of easy integration, low power consumption and ultra-fast response, and has broad application prospects in environmental monitoring, food safety and military fields.

[0007] The technical solution adopted in this invention is as follows:

[0008] A controllable extraction structure for the internal features of a 3T1C gas response sensor includes an N-type gas-sensitive field-effect transistor, a P-type gas-sensitive field-effect transistor, an output modulation field-effect transistor, and a fixed capacitor;

[0009] In this circuit, the source of the N-type gas-sensitive field-effect transistor is connected to the source of the P-type gas-sensitive field-effect transistor to form the first-stage output terminal, which is connected to the signal output terminal via a fixed capacitor; the drain of the N-type gas-sensitive field-effect transistor is connected to the driving voltage; the gate of the output modulation field-effect transistor is connected to the modulation voltage, and one of the source and drain of the output modulation field-effect transistor is connected to the signal output terminal, while the other is connected to the common ground terminal together with the drain of the P-type gas-sensitive field-effect transistor.

[0010] Furthermore, the connection method of the controllable extraction structure of the internal features of the 3T1C gas response sensor is replaced as follows: the drain of the N-type gas-sensitive field-effect transistor is connected to the drain of the P-type gas-sensitive field-effect transistor to form the first-stage output terminal; the source of the N-type gas-sensitive field-effect transistor is connected to the driving voltage; and the source of the P-type gas-sensitive field-effect transistor is connected to the common ground terminal.

[0011] Furthermore, the gates of the N-type gas-sensitive field-effect transistor and the P-type gas-sensitive field-effect transistor are the same gas-sensitive thin film, and their work function changes after the target gas is adsorbed.

[0012] Furthermore, the material of the gas-sensitive film is a metal such as palladium, nickel, gold, or silver, an organic material such as polyaniline or polythiophene, or a metal oxide such as zinc oxide or tin oxide.

[0013] Furthermore, the thickness of the gas-sensitive film is 1~50 nm.

[0014] Furthermore, the threshold voltages of the N-type gas-sensitive field-effect transistor and the P-type gas-sensitive field-effect transistor are the same, and the difference in their off-state currents does not exceed 10 times, and the difference in their on / off ratios does not exceed 10 times.

[0015] Furthermore, the channel material of the N-type gas-sensitive field-effect transistor is an N-type semiconductor material, specifically indium oxide, indium gallium zinc oxide, N-type doped silicon, zinc oxide, molybdenum disulfide, tungsten diselenide, or indium tin zinc oxide.

[0016] Furthermore, the channel material of the P-type gas-sensitive field-effect transistor is a P-type semiconductor material, specifically tellurium, tellurium oxide, a composite of tellurium oxide and selenium, carbon nanotubes, pentacene, poly(3-hexylthiophene), or P-type doped silicon.

[0017] Furthermore, the channel material thickness of the N-type gas-sensitive field-effect transistor and the P-type gas-sensitive field-effect transistor is 0.2~30nm.

[0018] Furthermore, the capacitance value of the fixed capacitor is 100 pF to 1 μF.

[0019] Furthermore, by changing the modulation voltage, the static resistance of the output modulation field-effect transistor is adjusted, thereby controlling the peak value of the gas response signal and the signal output time at the signal output terminal.

[0020] Furthermore, the static resistance of the output modulation field-effect transistor can be modulated in the range of 1 kΩ to 10 MΩ.

[0021] The working principle of the 3T1C gas response sensing feature controllable extraction structure proposed in this invention is as follows:

[0022] The N-type and P-type gas-sensitive field-effect transistors start working under the control of the driving voltage. When they are exposed to the target gas, the work function of the gas-sensitive film changes after adsorbing the target gas, which causes a change in their static resistance. Consequently, the output voltage at the first-stage output terminal changes, generating a voltage signal. Due to the adsorption process of the target gas, this voltage signal changes rapidly at first, then the trend slows down, and finally tends to stabilize. During the change of the voltage signal, the output modulation field-effect transistor and the fixed capacitor form a differentiating circuit, outputting a gas response signal from the signal output terminal.

[0023] On the one hand, the N-type gas-sensitive field-effect transistor and the P-type gas-sensitive field-effect transistor form an inverter structure, which can amplify and improve the performance of the target gas concentration response. On the other hand, by changing the modulation voltage and adjusting the static resistance of the output modulation field-effect transistor, the time constant of the differentiating circuit is controlled, and finally the peak value of the gas response signal and the signal output time at the signal output terminal are controlled. Moreover, the peak value of the gas response signal can be used as a characteristic value of the gas concentration.

[0024] Under the same output modulation field-effect transistor condition, the concentration of the target gas can be obtained by analyzing the ratio between the peak value of the gas response signal and the concentration of the target gas.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. This invention proposes a 3T1C gas response sensing feature controllable extraction structure. It utilizes the influence of the target gas on the channel resistance of different types of gas-sensitive field-effect transistors to realize the conversion and amplification of the target gas concentration response. By controlling the time constant of the differentiating circuit through the output modulation field-effect transistor, it achieves ultrafast extraction and controllable modulation of gas concentration features. It has the advantages of easy integration, low power consumption and ultrafast response.

[0027] 2. Compared with the traditional differentiating circuit composed of fixed capacitors and fixed resistors, the gas response signal output by this invention has a larger amplitude, more accurate detection effect, and controllable signal output time, which can greatly improve the gas detection speed.

[0028] 3. Preferably, the present invention can optimize the channel material of the field-effect transistor and the gate gas-sensitive material of the N-type and P-type gas-sensitive field-effect transistors, so that the 3T1C gas response sensor internal feature controllable extraction structure can be applied to different gas detection scenarios and needs, and has a wide range of applications in environmental safety, efficient industrial and agricultural production and other fields. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the controllable extraction structure of the 3T1C gas response sensor internal features proposed in Embodiment 1 of the present invention;

[0031] Figure 2 The transfer characteristic curve of the output modulation field-effect transistor in Embodiment 1 of the present invention;

[0032] Figure 3 This is a comparison chart of the output curve of the 3T1C gas response sensing internal feature controllable extraction structure proposed in Embodiment 1 of the present invention and the adsorption curve of a traditional gas-sensitive thin-film resistor.

[0033] Figure 4 The output curves in Example 1 of this invention are shown under the same hydrogen concentration and different modulation voltages.

[0034] Figure 5 The output curves in Embodiment 1 of the present invention are shown under the same modulation voltage and different hydrogen concentrations.

[0035] Figure 6 This is the curve showing the relationship between the gas response signal and the hydrogen concentration and modulation voltage in Embodiment 1 of the present invention;

[0036] Figure 7 This is a curve showing the relationship between the signal output time of the gas response signal and the hydrogen concentration and modulation voltage in Embodiment 1 of the present invention.

[0037] The explanations of the markings in the attached diagram are as follows:

[0038] 1. N-type gas-sensitive field-effect transistor, 2. P-type gas-sensitive field-effect transistor, 3. Fixed capacitor, 4. Output modulation field-effect transistor, 5. Drive voltage, 6. Modulation voltage, 7. Signal output terminal, 8. Common ground terminal. Detailed Implementation

[0039] To further understand the present invention, preferred embodiments are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims. All raw materials used in the present invention are not particularly limited in their source; they can be purchased commercially or prepared using conventional methods well known to those skilled in the art.

[0040] Example 1

[0041] This embodiment proposes a controllable extraction structure for the intrinsic features of a 3T1C gas response sensor, as shown in the following figure. Figure 1 As shown, it includes an N-type gas-sensitive field-effect transistor 1, a P-type gas-sensitive field-effect transistor 2, an output modulation field-effect transistor 4, and a fixed capacitor 3, that is, it consists of three field-effect transistors (denoted as T) and one capacitor (denoted as C), i.e., a 3T1C structure.

[0042] In this circuit, the drain of the N-type gas-sensitive field-effect transistor 1 is connected to the drain of the P-type gas-sensitive field-effect transistor 2 to form the first-stage output terminal, which is connected to the signal output terminal 7 via a fixed capacitor 3; the source of the N-type gas-sensitive field-effect transistor 1 is connected to the driving voltage 5; the gate of the output modulation field-effect transistor 4 is connected to the modulation voltage 6, and the drain of the output modulation field-effect transistor 4 is connected to the signal output terminal, while its source and the source of the P-type gas-sensitive field-effect transistor 2 are connected to the common ground terminal 8.

[0043] In this embodiment, the N-type gas-sensitive field-effect transistor 1 uses an N-doped silicon channel, and the P-type gas-sensitive field-effect transistor 2 uses a P-doped silicon channel. Both use a 5 nm thick Pd metal thin film as their gate gas-sensitive material. The threshold voltages of both the N-type and P-type gas-sensitive field-effect transistors are 0 V, and their off-state currents have the same switching ratio. The fixed capacitor 3 has a capacitance of 5 nF. The transfer characteristic curve of the output modulation field-effect transistor 4 is shown in the figure. Figure 2 As shown, the modulation voltages selected in this embodiment are 0V, -15V, -30V and -60V.

[0044] Using hydrogen as the target gas, the gas response process of the 3T1C gas response sensing feature controllable extraction structure proposed in this embodiment is as follows:

[0045] In the second second, hydrogen gas is introduced into the controllable extraction structure of the 3T1C gas response sensor. After the gate gas-sensitive films of N-type gas-sensitive field-effect transistor 1 and P-type gas-sensitive field-effect transistor 2 adsorb hydrogen gas, the work function changes, and the gate material shifts towards a forward bias. This causes the static resistance of N-type gas-sensitive field-effect transistor 1 to decrease and the static resistance of P-type gas-sensitive field-effect transistor 2 to increase. The output voltage at the first stage output terminal changes, generating a voltage signal. Due to the hydrogen adsorption process, this voltage signal changes rapidly at first, then the change slows down, and finally tends to stabilize. During the change of the voltage signal, the output modulation field-effect transistor 4 and the fixed capacitor 3 form a differentiating circuit, outputting the differential value of the voltage signal from the signal output terminal 7 as the gas response signal.

[0046] By changing the modulation voltage 6 and adjusting the static resistance of the output modulation field-effect transistor 4, the time constant of the differentiating circuit is controlled, ultimately achieving control over the peak value of the gas response signal and the signal output time at the signal output terminal 7. Furthermore, the peak value of the gas response signal can be used as a characteristic value of the hydrogen concentration.

[0047] For a hydrogen concentration of 1%, under a modulation voltage of -60 V and a driving voltage of 6 V and 1 V, the gas response signal output curve of the 3T1C gas response sensor internal feature controllable extraction structure described in this embodiment is as follows: Figure 3 As shown, the adsorption curve of the traditional gas-sensitive thin film (metal Pd thin film) resistor is compared with that of the traditional sensor. Compared with the traditional sensor, which requires the gas-sensitive thin film resistance value to stabilize before it can accurately output the corresponding hydrogen concentration information, this embodiment can obtain the characteristic value of hydrogen concentration within an adjustable range of 2.6 ms after hydrogen is introduced, which greatly improves the gas detection speed.

[0048] Figure 4 The output curves of the 3T1C gas response sensor internal feature controllable extraction structure described in this embodiment are shown under the same hydrogen concentration and different modulation voltages 6. Specifically, at a hydrogen concentration of 1%, when the modulation voltage 6 changes from 0 V to -60 V, the static resistance of the output modulation field-effect transistor 4 changes, the differential value of the voltage signal output by the signal output terminal 7 changes, and the signal output time also changes accordingly.

[0049] Figure 5 The output curves of the 3T1C gas response sensor internal feature controllable extraction structure described in this embodiment are shown under the same modulation voltage 6 and different hydrogen concentrations. Specifically, under the modulation voltage 6 of -60 V, when the hydrogen concentration changes from 0.2% to 1%, the peak value of the gas response signal output by the signal output terminal 7 changes accordingly.

[0050] Figure 6The curves showing the relationship between the gas response signal and hydrogen concentration and modulation voltage of the 3T1C gas response sensor with controllable feature extraction structure described in this embodiment are shown. It can be seen that under the same modulation voltage, the peak value of the gas response signal is proportional to the hydrogen concentration. By analyzing this proportional relationship, the concentration of the hydrogen to be measured can be quickly obtained.

[0051] Figure 7 The curves showing the relationship between the signal output time of the gas response signal of the controllable feature extraction structure of the 3T1C gas response sensor described in this embodiment and the hydrogen concentration and modulation voltage are shown. It can be seen that different modulation voltages have a certain modulation effect on the signal output time corresponding to different hydrogen concentrations. Compared with the traditional differential circuit, the signal output time is more controllable and the application scenarios are more extensive.

[0052] Calculations show that this embodiment can shorten the detection time of the metal Pd thin film itself from 4.65 s to a controllable time between 0.00248 and 0.643 s, which greatly improves the response speed and enables controllable extraction of the target gas concentration characteristics.

[0053] In summary, this embodiment utilizes the inverter and differential structure of a field-effect transistor, combined with the integrated structure design of a gas-sensitive field-effect transistor, to achieve controllable extraction of gas concentration characteristic signals. Furthermore, by adjusting the voltage, the acceleration effect of feature extraction can be regulated, making it applicable to various gas detection scenarios.

[0054] It should be noted that this is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A controllable extraction structure for the internal features of a 3T1C gas response sensor, characterized in that, This includes N-type gas-sensitive field-effect transistors, P-type gas-sensitive field-effect transistors, output modulation field-effect transistors, and fixed capacitors; In this circuit, the source of the N-type gas-sensitive field-effect transistor is connected to the source of the P-type gas-sensitive field-effect transistor to form the first-stage output terminal, which is connected to the signal output terminal via a fixed capacitor; the drain of the N-type gas-sensitive field-effect transistor is connected to the driving voltage; the gate of the output modulation field-effect transistor is connected to the modulation voltage, and one of its source and drain is connected to the signal output terminal, while the other, together with the drain of the P-type gas-sensitive field-effect transistor, is connected to the common ground terminal.

2. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 1, characterized in that, The connection method of the controllable extraction structure of the internal feature of the 3T1C gas response sensor is replaced as follows: the drain of the N-type gas field-effect transistor is connected to the drain of the P-type gas field-effect transistor to form the first stage output terminal; the source of the N-type gas field-effect transistor is connected to the driving voltage; and the source of the P-type gas field-effect transistor is connected to the common ground terminal.

3. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 1 or 2, characterized in that, The gates of the N-type gas-sensitive field-effect transistor and the P-type gas-sensitive field-effect transistor are made of the same gas-sensitive thin film.

4. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 3, characterized in that, The gas-sensitive film is made of palladium, nickel, gold, silver, polyaniline, polythiophene, zinc oxide, or tin oxide.

5. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 1 or 2, characterized in that, The threshold voltages of the N-type gas-sensitive field-effect transistor and the P-type gas-sensitive field-effect transistor are the same, and the difference in their off-state currents does not exceed 10 times, and the difference in their on / off ratios does not exceed 10 times.

6. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 1 or 2, characterized in that, The channel material of the N-type gas-sensitive field-effect transistor is an N-type semiconductor material, specifically indium oxide, indium gallium zinc oxide, N-type doped silicon, zinc oxide, molybdenum disulfide, tungsten diselenide, or indium tin zinc oxide.

7. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 1 or 2, characterized in that, The channel material of the P-type gas-sensitive field-effect transistor is a P-type semiconductor material, specifically tellurium, tellurium oxide, a composite of tellurium oxide and selenium, carbon nanotubes, pentacene, poly(3-hexylthiophene), or P-type doped silicon.

8. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 1 or 2, characterized in that, The capacitance value of the fixed capacitor is 100 pF to 1 μF.

9. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 1 or 2, characterized in that, By changing the modulation voltage, the static resistance of the output modulation field-effect transistor is adjusted, thereby controlling the peak value of the gas response signal and the signal output time at the signal output terminal.

10. The controllable extraction structure of the 3T1C gas response sensor's internal features according to claim 9, characterized in that, The static resistance of the output modulation field-effect transistor can be modulated in the range of 1 kΩ to 10 MΩ.

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