CN113588730A

CN113588730A - Semiconductor type gas sensor and application thereof in expiration type alcohol detection

Info

Publication number: CN113588730A
Application number: CN202110898428.2A
Authority: CN
Inventors: 奚亚男; 胡保帅; 崔皓博
Original assignee: Guangzhou Yuxin Intelligent Technology Research Institute Co ltd
Current assignee: Guangzhou Yuxin Intelligent Technology Research Institute Co ltd
Priority date: 2021-08-05
Filing date: 2021-08-05
Publication date: 2021-11-02

Abstract

The invention provides a semiconductor type gas sensor and application thereof in expiration type alcohol detection. The electrode comprises an electrode substrate (1), a metal electrode and an electrode pad (6), wherein the metal electrode is positioned on the surface of the electrode substrate (1), and the tail end of the metal electrode is connected with the electrode pad (6); the metal electrodes comprise a first electrode matrix (2) and a second electrode matrix (3), are formed by circular interdigital strips (7), and are symmetrically distributed at two ends of the surface of the electrode substrate (1); the first electrode matrix (2) and the second electrode matrix (3) are arranged in parallel in a mutually crossed mode, the upper end parts of the first electrode matrix and the second electrode matrix are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, and the first array interdigital strip and the second array interdigital strip are arranged in a crossed mode in a parallel staggered comb-shaped concentric circle mode. The semiconductor gas sensitive sensor is a resistance type semiconductor sensor, can realize gas detection in a normal temperature environment, and can be used for an expiration type alcohol detection instrument.

Description

Semiconductor type gas sensor and application thereof in expiration type alcohol detection

Technical Field

The invention belongs to the field of gas sensors, and relates to a semiconductor type gas sensor and application thereof in expiration type alcohol detection.

Background

The semiconductor gas sensor is a gas sensor using a semiconductor gas sensor as a sensitive element, is a common gas sensor, is widely applied to the fields of families, industries and the like at present, and is suitable for a combustible gas leakage detection device.

Semiconductor type gas sensors can be classified into resistive type and non-resistive type according to the physical properties of semiconductors. The non-resistance type semiconductor gas sensor detects the composition or concentration of gas by using the change of resistance value when the semiconductor contacts the gas, and the gas is directly or indirectly detected by changing some characteristics of the semiconductor according to the adsorption and reaction of the gas.

The resistance type semiconductor gas sensor is manufactured by utilizing the change of the resistance value of a sensitive element caused by the oxidation-reduction reaction of gas on the surface of a semiconductor. When the gas contacts the surface of the semiconductor and is adsorbed, the adsorbed molecules firstly diffuse freely on the surface of the object, lose kinetic energy, evaporate a part of molecules, and generate thermal decomposition and adsorb on the surface of the object by the other part of residual molecules. When the work function of the semiconductor is smaller than the affinity of the adsorbed molecules, the adsorbed molecules will take electrons away from the device and become negative ions to adsorb, and the surface of the semiconductor presents a charge layer, so that the surface resistance of the semiconductor is reduced, and the specific sensitive gas can be detected.

The semiconductor type gas-sensitive sensor has the advantages of high sensitivity, convenient operation, small volume, low cost, short response time and recovery time and the like, but also has the defects of poor stability and selectivity, complex sensitive mechanism, high working temperature, short service life of devices and the like.

The alcohol detector is an important detection tool for traffic police law enforcement to judge whether a driver drives drunk, can effectively avoid important traffic accidents, and can be used for detecting the alcohol content in the exhaled air of a human body in other occasions. Due to the demands of spot sampling and instant detection, the breath type/expiration type alcohol detection device is currently most widely applied.

Common expiration type alcohol detectors are classified into a combustion battery type (electrochemical type) and a semiconductor type, wherein the semiconductor type alcohol detector has a small size, low cost, poor stability, and large influence by a detection environment, so that accuracy of a detection result is influenced, and therefore, it is necessary to develop a gas sensor with high precision and high stability.

Therefore, the problem to be solved by the present invention is to overcome the defects of the prior art, and provide a semiconductor type gas sensor with high precision and high stability, which can be detected in a normal temperature environment, in particular to an interdigital electrode as a core device of the sensor, and can improve the performance of the electrode while realizing the integration of a micro electrode, so that the sensor is suitable for gas-sensitive detection and can be applied to an expiratory alcohol detection device.

Disclosure of Invention

In view of the above, the present invention provides a semiconductor type gas sensor and its application in breath alcohol detection.

The purpose of the invention is realized by the following technical scheme:

a semiconductor type gas sensor comprises an interdigital electrode, and specifically comprises an electrode substrate (1), a metal electrode and an electrode pad (6), wherein the metal electrode is positioned on the surface of the electrode substrate (1), and the tail end of the metal electrode is connected with the electrode pad (6); the metal electrode has an electrode matrix structure and comprises a first electrode matrix (2) and a second electrode matrix (3), wherein the first electrode matrix (2) and the second electrode matrix (3) are formed by circular interdigital strips (7) and are symmetrically distributed at two ends of the surface of the electrode substrate (1); the first electrode matrix (2) and the second electrode matrix (3) are arranged in parallel and cross each other.

The lower end parts of the first electrode matrix (2) and the second electrode matrix (3) extend to the tail end of the electrode substrate (1) and are respectively connected with the electrode pads (6).

Furthermore, the width of the circular interdigital strip (7) is 1-50 μm.

The upper end parts of the first electrode matrix (2) and the second electrode matrix (3) are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, the first array interdigital strip and the second array interdigital strip are arranged in a crossed mode in a parallel staggered comb-shaped concentric circle mode, and the distances between the first array interdigital strip and the second array interdigital strip are the same.

Furthermore, the distance between the first array of interdigital strips and the second array of interdigital strips is 1-50 μm.

The interdigital electrode also comprises an ion selective film (5), and the ion selective film (5) is positioned on the surface of the metal electrode.

Furthermore, the interdigital electrode also comprises an electrode protection layer (4), and the electrode protection layer (4) is positioned between the ion selective film (5) and the metal electrode.

Further, the electrode substrate (1) can be silicon-based, ceramic, polymer materials, including silicon dioxide, aluminum nitride, aluminum oxide, silicon carbide, glass, piezoelectric ceramics, microwave dielectric ceramics.

Further, the metal electrode comprises a conductive inner layer and a reaction layer, wherein the conductive inner layer comprises a Ti layer, and the thickness of the Ti layer is 0.02-0.20 mu m; the reaction layer comprises an Au layer, and the thickness of the Au layer is 0.10-0.50 μm.

The circular interdigital strips (7) are circular metal electrode strips and are uniform in width.

Two electrode pads (6) connected at the ends of the first electrode matrix (2) and the second electrode matrix (3) are used for connecting external circuits.

The electrode protection layer (4) can be used for protecting a metal electrode circuit and can also be used for preventing the ion selective film (5) from falling off easily.

Fig. 1 shows a schematic diagram of a semiconductor gas sensor according to embodiment 1 of the present invention. The electrode comprises an electrode substrate (1), a metal electrode, an electrode pad (6) and an ion selective film (5), wherein the metal electrode is positioned on the surface of the electrode substrate (1), the metal electrode comprises a first electrode matrix (2) and a second electrode matrix (3), the first electrode matrix (2) and the second electrode matrix (3) are formed by circular interdigital strips (7) and are symmetrically distributed at two ends of the surface of the electrode substrate (1), and the width of each circular interdigital strip (7) is 5 mu m. The lower end parts of the first electrode matrix (2) and the second electrode matrix (3) extend to the lower end of the same side of the electrode substrate (1) and are respectively connected with the two electrode pads (6). The upper end parts of the first electrode matrix (2) and the second electrode matrix (3) are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, wherein the first array interdigital strip and the second array interdigital strip are arranged in a crossed mode in a parallel staggered tooth comb-shaped concentric circle mode, and 5 pairs of interdigital strips are provided. The spacing between the first array of interdigitated fingers and the second array of interdigitated fingers is the same, 5 μm. The ion selective film (5) is positioned on the surface of the metal electrode.

Fig. 2 is a schematic side view of a semiconductor gas sensor according to embodiment 1 of the present invention. As can be seen from the figure, the interdigital electrode comprises an electrode substrate (1), a metal electrode and an ion selective film (5) from bottom to top in sequence. The metal electrode comprises a first electrode matrix (2) and a second electrode matrix (3) which are symmetrically distributed, and the ion selective film (5) is modified on the surface of the metal electrode.

Fig. 3 is a schematic view of a semiconductor gas sensor according to embodiment 2 of the present invention. The electrode comprises an electrode substrate (1), a metal electrode, an electrode pad (6) and an ion selective film (5), wherein the metal electrode is positioned on the surface of the electrode substrate (1), the metal electrode comprises a first electrode matrix (2) and a second electrode matrix (3), the first electrode matrix (2) and the second electrode matrix (3) are formed by circular interdigital strips (7) and are symmetrically distributed at two ends of the surface of the electrode substrate (1), and the width of each circular interdigital strip (7) is 10 mu m. The lower end parts of the first electrode matrix (2) and the second electrode matrix (3) respectively extend to the tail ends of the two sides of the electrode substrate (1) and are respectively connected with the two electrode pads (6). The upper end parts of the first electrode matrix (2) and the second electrode matrix (3) are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, wherein the first array interdigital strip and the second array interdigital strip are arranged in a crossed mode in a parallel staggered tooth comb-shaped concentric circle mode, and 15 pairs of interdigital strips are shared. The spacing between the first array of interdigitated fingers and the second array of interdigitated fingers is the same and is 10 μm. The ion selective film (5) is positioned on the surface of the metal electrode. The electrode protection layer (4) is modified on the surface of the metal electrode, covers the position of the circular interdigital strip (7), and is modified with the ion selective film (5).

Fig. 4 is a schematic side view of a semiconductor gas sensor according to embodiment 2 of the present invention. As can be seen from the figure, the interdigital electrode sequentially comprises an electrode substrate (1), a metal electrode, an electrode protection layer (4) and an ion selective film (5) from bottom to top. The metal electrode comprises a first electrode matrix (2) and a second electrode matrix (3) which are symmetrically distributed, an electrode protection layer (4) is modified on the surface of the metal electrode, and an ion selective film (5) is modified on the surface of the metal electrode.

Fig. 5 is a schematic diagram of a semiconductor type gas sensor according to embodiment 3 of the present invention. The electrode is made of silicon-based materials and comprises an electrode substrate (1), a metal electrode, an electrode pad (6) and an ion selective film (5), wherein the metal electrode is located on the surface of the electrode substrate (1), the metal electrode comprises a first electrode matrix (2) and a second electrode matrix (3), the first electrode matrix (2) and the second electrode matrix (3) are formed by circular interdigital strips (7) and are symmetrically distributed at two ends of the surface of the electrode substrate (1), and the width of each circular interdigital strip (7) is 1 mu m. The lower end parts of the first electrode matrix (2) and the second electrode matrix (3) respectively extend to the tail ends of the two sides of the electrode substrate (1) and are respectively connected with the two electrode pads (6). The upper end parts of the first electrode matrix (2) and the second electrode matrix (3) are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, wherein the first array interdigital strip and the second array interdigital strip are arranged in a crossed mode in a parallel staggered tooth comb-shaped concentric circle mode, and the total number of the interdigital strips is 25. The spacing between the first array of interdigitated fingers and the second array of interdigitated fingers is the same, 1 μm.

The invention also aims to provide application of the semiconductor type gas sensor in normal temperature gas detection. The breath alcohol detection device can be particularly used for breath alcohol detection devices.

The semiconductor gas sensor provided by the invention is a resistance semiconductor gas sensor, can detect the type and concentration of gas by using the resistance value change when an interdigital electrode contacts the gas, and has the characteristics of miniaturization, high precision, high sensitivity and good stability.

The semiconductor type gas sensor can detect gas in a normal temperature environment, gas molecules are in contact with the ion selective film (5), then response signals are generated on the electrode matrix and transmitted to a circuit through the electrode bonding pad (6), and the detection result is displayed through the circuit.

Fig. 6 shows a schematic diagram of a semiconductor gas sensor according to the present invention. The interdigital electrodes of the core sensor device are bonded by gold wires to connect electrode pads (6) at two ends with the whole device, so that a sensor array can be formed, as shown in figure 7.

As shown in fig. 8, a graph of the detection resistance of the semiconductor type gas sensor provided by the present invention is shown. As can be seen from the figure, taking the value of point a as an example, the resistance value can be calculated as follows: 6.566/(3.009x 10)^-10) 20G Ω. It can be seen that as the voltage increases, the resistance of the electrode also increases, and the electrode has a good linear relationship in a certain voltage range. The semiconductor gas sensor of the present invention was demonstrated to have good resistance-type semiconductor gas sensor performance.

As shown in fig. 9, it is a fitting graph of the concentration and resistance value of alcohol detected by the semiconductor type gas sensor provided by the present invention. It can be seen from the figure that, as the alcohol concentration increases, the resistance value of the gas sensor gradually decreases, a good linear relationship exists between the resistance value of the gas sensor and the concentration of a gas detection object, and the fitting value is 0.9896, which indicates that the semiconductor type gas sensor provided by the invention can perform expiratory detection on alcohol within a certain concentration range in a normal temperature environment.

The invention has the beneficial effects that:

(1) the invention integrally fixes two electrodes on a substrate to realize the purpose of micro-electrode integration, and the integration immobilization and the miniaturization of the distance between the electrodes can lead the resistance value between the electrodes to be immobilized, eliminate the detection interference caused by the concentration change of the detected substance, the metal electrodes are designed into electrode matrixes which are symmetrically distributed, and the concentric circular comb-tooth-shaped interdigital strips are alternately arranged at intervals and have the same micro-distance, thereby playing the role of amplifying the detection current, realizing the purposes of improving the detection sensitivity and the detection data precision of the electrodes, leading the electrodes to have the characteristics of high precision and high stability, and simultaneously realizing the miniaturization of devices, thus leading the electrodes to be suitable for sensor arrays and hand-held breath alcohol detection devices.

(2) The electrode pad is arranged on the surface of the electrode and is connected with the whole device through gold wire binding, and then a plurality of semiconductor devices can be communicated to form a sensor array, so that the detection result is more precise and accurate.

(3) According to the invention, the electrode protection layer and the ion selective film layer are designed on the surface of the interdigital electrode, the structure of the interdigital electrode is designed to be attached to the electrode matrix, and the modified film layer and the metal electrode form the composite electrode, so that the internal resistance of the electrode is reduced, the sensitivity and stability of the electrode are further improved, and the interdigital electrode is suitable for resistance-type gas-sensitive detection in a normal-temperature environment.

Drawings

The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be obtained on the basis of the following drawings without inventive effort.

Fig. 1 is a schematic view of a semiconductor type gas sensor provided in embodiment 1 of the present invention;

fig. 2 is a schematic side view of a semiconductor type gas sensor provided in example 1 of the present invention;

fig. 3 is a schematic view of a semiconductor type gas sensor provided in embodiment 2 of the present invention;

FIG. 4 is a schematic side view of a semiconductor type gas sensor provided in example 2 of the present invention;

FIG. 5 is a schematic diagram of a semiconductor type gas sensor provided in embodiment 3 of the present invention;

FIG. 6 is a schematic diagram of a semiconductor type gas sensor provided by the present invention;

FIG. 7 is a schematic diagram of a semiconductor type gas sensor array provided by the present invention;

FIG. 8 is a graph of the detection resistance of the semiconductor gas sensor provided by the present invention;

FIG. 9 is a fitting graph of the alcohol concentration and the resistance value detected by the semiconductor type gas sensor provided by the present invention.

Illustration of the drawings:

1. an electrode substrate; 2. a first matrix of electrodes; 3. a second matrix of electrodes; 4. an electrode protection layer; 5. an ion-selective membrane; 6. an electrode pad; 7. circular interdigitated fingers.

Detailed Description

In order that the objects, aspects and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the following detailed description and the accompanying drawings.

The specific embodiment of the invention comprises the following steps:

an interdigital electrode of a core device of a semiconductor type gas sensor specifically comprises an electrode substrate 1, a metal electrode, an electrode pad 6 and an ion selective film 5.

The electrode substrate (1) can be silicon-based, ceramic or high polymer materials, including silicon dioxide, aluminum nitride, aluminum oxide, silicon carbide, glass, piezoelectric ceramic and microwave dielectric ceramic.

The metal electrode comprises a conductive inner layer and a reaction layer, wherein the conductive inner layer comprises a Ti layer, and the thickness of the Ti layer is 0.02-0.20 mu m; the reaction layer comprises an Au layer, and the thickness of the Au layer is 0.10-0.50 μm.

The metal electrodes are located on the surface of the electrode substrate 1 and comprise a first electrode matrix 2 and a second electrode matrix 3, the first electrode matrix 2 and the second electrode matrix 3 are formed by circular interdigital strips 7 and are symmetrically distributed at two ends of the surface of the electrode substrate 1, and the width of each circular interdigital strip 7 is 1-50 microns.

The lower end portions of the first electrode matrix 2 and the second electrode matrix 3 extend to the end of the electrode substrate 1, and are connected to two electrode pads 6, respectively.

The upper ends of the first electrode matrix 2 and the second electrode matrix 3 are provided with semicircular comb-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, wherein the first array interdigital strip and the second array interdigital strip are arranged in a parallel staggered tooth comb-shaped concentric circle mode in an intersecting manner. The maximum diameter of the circular metal electrode formed by the first electrode matrix 2 and the second electrode matrix 3 is 1-5 mm.

The distance between the first array interdigital strip and the second array interdigital strip is the same and is 1-50 mu m.

The ion selective film 5 is decorated on the surface of the metal electrode and covers the position of the circular interdigital strip 7.

An electrode protection layer 4 is located between the metal electrode and the ion selective membrane 5.

Example 1

The present embodiment provides a semiconductor type gas sensor, as shown in fig. 1, the interdigital electrode of the core device comprises an electrode substrate 1, a metal electrode, an electrode pad 6 and an ion selective membrane 5.

The electrode substrate 1 is made of silicon dioxide, the size of the whole electrode is 6.0mm x 4.0mm, and the thickness is 0.5 mm. The metal electrode comprises a conductive inner layer and a reaction layer, wherein the conductive inner layer is a Ti layer, and the thickness of the conductive inner layer is 0.02 mu m; the reaction layer was an Au layer with a thickness of 0.10. mu.m.

The metal electrodes are positioned on the surface of the electrode substrate 1 and comprise a first electrode matrix 2 and a second electrode matrix 3, the first electrode matrix 2 and the second electrode matrix 3 are formed by circular interdigital strips 7 and are symmetrically distributed at two ends of the surface of the electrode substrate 1, wherein the width of the circular interdigital strips 7 is 5 microns.

The lower end portions of the first electrode matrix 2 and the second electrode matrix 3 extend to the lower end of the same side of the electrode substrate 1 and are connected to two electrode pads 6, respectively.

The upper ends of the first electrode matrix 2 and the second electrode matrix 3 are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, wherein the first array interdigital strip and the second array interdigital strip are arranged in a crossed manner in a parallel staggered tooth comb-shaped concentric circle mode, and 5 pairs of interdigital strips are provided. The maximum diameter of the circular metal electrodes formed by the first electrode matrix 2 and the second electrode matrix 3 is 3 mm.

The spacing between the first array of interdigitated fingers and the second array of interdigitated fingers is the same, 5 μm.

As shown in fig. 2, the ion selective membrane 5 is modified on the surface of the metal electrode to cover the position of the circular interdigital strip 7.

Example 2

The present embodiment provides a semiconductor type gas sensor, as shown in fig. 3, the interdigital electrode of the core device includes an electrode substrate 1, a metal electrode, an electrode pad 6, an electrode protection layer 4 and an ion selective film 5.

The electrode substrate 1 is made of ceramic, the size of the whole electrode is 6.0mm x 4.0mm, and the thickness is 0.5 mm. The metal electrode comprises a conductive inner layer and a reaction layer, wherein the conductive inner layer is a Ti layer, and the thickness of the conductive inner layer is 0.02 mu m; the reaction layer was an Au layer with a thickness of 0.10. mu.m.

The metal electrodes are positioned on the surface of the electrode substrate 1 and comprise a first electrode matrix 2 and a second electrode matrix 3, the first electrode matrix 2 and the second electrode matrix 3 are formed by circular interdigital strips 7 and are symmetrically distributed at two ends of the surface of the electrode substrate 1, wherein the width of each circular interdigital strip 7 is 10 microns.

The lower end portions of the first electrode matrix 2 and the second electrode matrix 3 extend to the ends of both sides of the electrode substrate 1, respectively, and are connected to two electrode pads 6, respectively.

The upper ends of the first electrode matrix 2 and the second electrode matrix 3 are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, wherein the first array interdigital strip and the second array interdigital strip are arranged in a crossed manner in a parallel staggered comb-shaped concentric circle mode, and 15 pairs of interdigital strips are provided. The maximum diameter of the circular metal electrodes formed by the first electrode matrix 2 and the second electrode matrix 3 is 3 mm.

The spacing between the first array of interdigitated fingers and the second array of interdigitated fingers is the same and is 10 μm.

As shown in fig. 4, the electrode protection layer 4 is modified on the surface of the metal electrode to cover the position of the circular interdigital strip 7, and the surface of the electrode protection layer is modified with the ion selective film 5.

Example 3

The present embodiment provides a semiconductor type gas sensor, as shown in fig. 5, the interdigital electrode of the core device includes an electrode substrate 1, a metal electrode, an electrode pad 6, an electrode protection layer 4 and an ion selective film 5.

The electrode substrate 1 is a polymer substrate, the size of the whole electrode is 3.0mm x 1.0mm, and the thickness is 0.5 mm. The metal electrode comprises a conductive inner layer and a reaction layer, wherein the conductive inner layer is a Ti layer, and the thickness of the conductive inner layer is 0.15 mu m; the reaction layer was an Au layer with a thickness of 0.20. mu.m.

The metal electrodes are positioned on the surface of the electrode substrate 1 and comprise a first electrode matrix 2 and a second electrode matrix 3, the first electrode matrix 2 and the second electrode matrix 3 are formed by circular interdigital strips 7 and are symmetrically distributed at two ends of the surface of the electrode substrate 1, wherein the width of each circular interdigital strip 7 is 1 micrometer.

The upper ends of the first electrode matrix 2 and the second electrode matrix 3 are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, wherein the first array interdigital strip and the second array interdigital strip are arranged in a crossed manner in a parallel staggered comb-shaped concentric circle mode, and the total number of the interdigital strips is 25 pairs. The maximum diameter of the circular metal electrodes formed by the first electrode matrix 2 and the second electrode matrix 3 is 1 mm.

The spacing between the first array of interdigitated fingers and the second array of interdigitated fingers is the same, 1 μm.

Example 4

The embodiment provides a semiconductor type gas sensor, and a core device interdigital electrode of the semiconductor type gas sensor comprises an electrode substrate 1, a metal electrode, an electrode pad 6, an electrode protection layer 4 and an ion selective film 5.

The electrode substrate 1 is made of silicon dioxide, the size of the whole electrode is 5.0mm x 3.0mm, and the thickness is 0.5 mm. The metal electrode comprises a conductive inner layer and a reaction layer, wherein the conductive inner layer is a Ti layer and has the thickness of 0.20 mu m; the reaction layer was an Au layer with a thickness of 0.50 μm.

The upper ends of the first electrode matrix 2 and the second electrode matrix 3 are provided with semicircular tree-shaped interdigital strips in the form of concentric circles, namely a first array interdigital strip and a second array interdigital strip, wherein the first array interdigital strip and the second array interdigital strip are arranged in a crossed manner in a parallel staggered comb-shaped concentric circle mode, and the total number of the interdigital strips is 25 pairs. The maximum diameter of the circular metal electrodes formed by the first electrode matrix 2 and the second electrode matrix 3 is 3 mm.

The spacing between the first array of interdigitated fingers and the second array of interdigitated fingers is the same and is 25 μm.

Example 5

The application of the semiconductor type gas sensor in normal temperature gas detection:

the semiconductor type gas sensor provided in embodiment 3 is packaged as a gas-sensitive detection sensor device, as shown in fig. 6, interdigital electrodes of a core device of the sensor are bonded by gold wires to connect electrode pads 6 at two ends with an integral device, so as to form a complete gas-low temperature gas biosensor/MEMS type temperature and humidity sensor, and a plurality of sensor devices can form a sensor array, as shown in fig. 7.

The semiconductor gas sensor prepared above is used to detect the change of the resistance value along with the voltage under the normal temperature environment to obtain the graph of fig. 8, the detection data of point a is used, and the resistance value can be calculated as follows: 6.566/(3.009x 10)^-10) 20G Ω. It can be seen that the resistance value of the electrode increases with the increase of the voltage, which shows that the semiconductor type gas sensor of the present invention has good performance of the resistance type semiconductor gas sensor, and can detect gas at normal temperature.

Example 6

The application of the semiconductor type gas sensor in breath alcohol detection is as follows:

the semiconductor type gas sensor provided in example 3 was used as a core device for breath alcohol testing, alcohol gases of different concentrations were tested at room temperature, and the change in resistance value was calculated and recorded, and the test results were obtained as follows.

The linear relation graph of the resistance value and the alcohol concentration of the semiconductor gas sensor is obtained according to the recorded data, and as shown in fig. 9, the semiconductor gas sensor provided by the invention can be used as a miniaturized and high-precision sensing device and can be used for breath alcohol detection at normal temperature.

Comparative example 1

the semiconductor gas sensor provided in example 1 was used as a core device for breath alcohol testing, and alcohol gas with a specific concentration was tested in a room temperature environment, and a commercial breath alcohol tester was used for the detection under the same conditions.

The test results of the two alcohol test devices were calculated and recorded, as shown in the following table.

From the above table, the accuracy of the semiconductor type gas sensor for detecting alcohol gas at normal temperature is approximately similar to that of a commercial expiration type alcohol detector, the error is less than or equal to 5%, the semiconductor type gas sensor is superior to the commercial expiration type alcohol detector in the aspects of overall performance and convenience in use, and the semiconductor type gas sensor can be used for a drunk driving detector.

Comparative example 2

the semiconductor type gas sensor provided in example 1 was used as a core device for breath alcohol testing, and alcohol gases with different concentrations were tested under normal temperature conditions, and were tested by a commercial breath alcohol tester under the same conditions.

The test time and recovery time for both alcohol test devices were recorded as specified in the table below.

The above table shows that the semiconductor type gas sensor provided by the invention can detect at normal temperature, so that the detection time and recovery time are greatly shortened compared with a commercial expiration type alcohol detector, the detection efficiency is improved, and the semiconductor type gas sensor has the characteristics of high precision and high sensitivity.

Setting the power supply of the sensing device as a rated voltage, measuring once every 5 minutes by using gas with a certain concentration, continuously measuring for 50 times, detecting whether the sensing device can normally detect the alcohol gas, recording data, and measuring and calculating the continuous measurement performance of the sensing device, wherein the specific table is as follows.

	EXAMPLE 1 semiconductor gas sensor	Commercial instrument
			Number of consecutive measurements	Not less than 100 times	Not less than 50 times

Tests show that the semiconductor type gas sensor provided by the invention has excellent continuous testing performance and good repeatability and stability.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single technical solution, and such description is for clarity only, and those skilled in the art should take the description as a whole, and the technical solutions in the embodiments may be combined appropriately to form other embodiments that those skilled in the art can understand. The technical details not described in detail in the present invention can be implemented by any of the prior arts in the field. In particular, all technical features of the invention which are not described in detail can be achieved by any prior art.

Claims

1. A semiconductor type gas sensor comprises interdigital electrodes, and is characterized by comprising an electrode substrate (1), metal electrodes and electrode pads (6), wherein the metal electrodes are positioned on the surface of the electrode substrate (1), and the tail ends of the metal electrodes are connected with the electrode pads (6); the metal electrode has an electrode matrix structure and comprises a first electrode matrix (2) and a second electrode matrix (3), wherein the first electrode matrix (2) and the second electrode matrix (3) are formed by circular interdigital strips (7) and are symmetrically distributed at two ends of the surface of the electrode substrate (1); the first electrode matrix (2) and the second electrode matrix (3) are arranged in parallel across each other.

2. A semiconductor gas sensor as claimed in claim 1, wherein the lower ends of the first and second electrode matrices (2, 3) extend to the ends of the electrode substrate (1) and are connected to the electrode pads (6), respectively.

3. The semiconductor gas sensor according to claim 1, wherein the width of the circular interdigital strip (7) is 1-50 μm.

4. A semiconductor gas sensor as claimed in claim 1, wherein the upper ends of the first electrode matrix (2) and the second electrode matrix (3) have semi-circular tree-shaped interdigitating fingers in the form of concentric circles, respectively a first array of interdigitating fingers and a second array of interdigitating fingers, the first array of interdigitating fingers and the second array of interdigitating fingers being arranged in parallel staggered comb-shaped concentric circles, the spacing between the first array of interdigitating fingers and the second array of interdigitating fingers being the same.

5. The semiconductor gas sensor of claim 4, wherein the first array of interdigitated fingers and the second array of interdigitated fingers have a pitch of 1-50 μm.

6. The semiconductor gas sensor according to claim 1, wherein the circular interdigital electrode further comprises an ion-selective thin film (5), and the ion-selective thin film (5) is decorated on the surface of the metal electrode.

7. A semiconductor gas sensor according to claim 6, characterized in that the circular interdigitated electrodes further comprise an electrode protection layer (4), the electrode protection layer (4) being located between the ion-selective membrane (5) and the metal electrodes.

8. The semiconductor type gas sensor according to claim 1, wherein the metal electrode comprises a conductive inner layer and a reaction layer, wherein the conductive inner layer comprises a Ti layer, and the thickness of the Ti layer is 0.02-0.20 μm; the reaction layer comprises an Au layer, and the thickness of the Au layer is 0.10-0.50 μm.

9. Use of the semiconductor type gas sensor according to any one of claims 1 to 8 in normal temperature gas detection.

10. The use of the semiconductor gas sensor of claim 9 in ambient gas detection, wherein the gas sensor is used in an expired alcohol detection device.