Gas sensing device

Abstract

A gas sensing device includes a substrate, a first transistor, a second transistor, a first metal electrode layer, a second metal electrode layer, a first sensing material layer, an interdigital electrode, and a second sensing material layer. The first transistor and the second transistor are formed in the substrate. The first metal electrode layer, the second metal electrode layer and the first sensing material layer are formed on the first transistor and the second transistor, the first metal electrode layer is electrically connected to the source end of the first transistor and the drain end of the second transistor, and the first sensing material layer is located on the first metal electrode layer and the second metal electrode layer. The interdigital electrodes are formed on the first metal electrode layer, the second metal electrode layer and the first sensing material layer. The second sensing material layer is formed on the interdigital electrodes.

Description

Technical Field

[0001] The present invention relates to a gas sensing device, and in particular to a structure of a gas sensing device. Background Art

[0002] Gas sensing units often need to be paired with other electronic devices (such as resistors, analog-to-digital converters (ADC) or processors, etc.) to enable gas sensors to be used in life. However, the ratio of the gas sensing unit to the paired resistance value must be equal to 1 or close to 1 to reduce the resolution requirements of the analog-to-digital converter. In addition, when the gas sensing unit is placed in a package, the colloid of the package will produce stress on the gas sensing unit, causing the resistance value of the gas sensing unit to change, thereby increasing the difference between the resistance value of the gas sensing unit and the paired resistance value. In order to obtain accurate gas sensing results, it is necessary to optimize the gas sensing device. Summary of the invention

[0003] The gas sensing device and structure proposed by the present invention form a plurality of sub-sensing units below the main gas sensing unit, and utilize the series connection and parallel connection of the sub-sensing units to form a matching resistor with a resistance value substantially similar to the main gas sensing unit, so as to reduce the resolution requirement of the analog-to-digital converter. In addition, the series connection and parallel connection of the sub-sensing units can also be used to offset the change in the resistance value of the gas sensing unit caused by packaging, so that the matching resistance value is close to the resistance value of the main gas sensing unit, thereby reducing the resolution requirement of the analog-to-digital conversion circuit.

[0004] In view of this, the present invention proposes a gas sensing device, comprising a substrate, a first transistor, a second transistor, a first metal electrode layer, a second metal electrode layer, a first sensing material layer, an interdigitated electrode and a second sensing material layer. The first transistor is formed in the substrate and comprises a first gate terminal, a first drain terminal and a first source terminal. The second transistor is formed in the substrate and comprises a second gate terminal, a second drain terminal and a second source terminal. The first metal electrode layer is formed on the first transistor and the second transistor and is electrically connected to the first source terminal and the second drain terminal. The second metal electrode layer is formed on the first transistor and the second transistor. The first sensing material layer is formed on the first metal electrode layer and the second metal electrode layer and is electrically connected to the first metal electrode layer and the second metal electrode layer. The interdigitated electrode is formed on the first metal electrode layer, the second metal electrode layer and the first sensing material layer. The second sensing material layer is formed on the interdigitated electrode.

[0005] According to one embodiment of the present invention, the gas sensing device further comprises a metal heating layer. The metal heating layer is formed on the first metal electrode layer, the second metal electrode layer and the sensing material layer, wherein the interdigitated electrode is formed on the metal heating layer, and the metal heating layer is used to improve the sensitivity of the second sensing material.

[0006] According to one embodiment of the present invention, the gas sensing device further includes a gas sensing unit and a first sub-sensing unit. The gas sensing unit is composed of the interdigitated electrode and the second sensing material layer. The first sub-sensing unit is composed of the first transistor, the second transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer. The interdigitated electrode is electrically connected to the first drain terminal. The first metal electrode layer, the first sensing material layer and the second metal electrode layer of the first sub-sensing unit form a first internal resistor. When the first transistor is turned on according to the signal received by the first gate terminal, the internal resistor of the gas sensing unit and the first sub-sensing unit are connected in series with the gas sensing unit.

[0007] According to one embodiment of the present invention, the gas sensing device further includes a second sub-sensing unit. The second sub-sensing unit is composed of the additional first transistor, the second transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer. The first drain terminal of the second sub-sensing unit is electrically connected to the interdigitated electrode. The first metal electrode layer, the first sensing material layer and the second metal electrode layer of the second sub-sensing unit form a second internal resistor. When the second transistor of the first sub-sensing unit is turned on and the first transistor of the second sub-sensing unit is turned on, the first internal resistor, the second internal resistor and the gas sensing unit are connected in series with each other.

[0008] According to another embodiment of the present invention, the gas sensing device further includes a second sub-sensing unit. The second sub-sensing unit is composed of the additional first transistor, the second transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer. The first metal electrode layer, the first sensing material layer and the second metal electrode layer of the second sub-sensing unit form a second internal resistor. The second metal electrode layer of the first sub-sensing unit is electrically connected to the second metal electrode layer of the second sub-sensing unit, and the first metal electrode layer of the second sub-sensing unit is electrically connected to the second source terminal of the first sub-sensing unit. When the second transistor of the first sub-sensing unit is turned on and the first transistor of the second sub-sensing unit is turned on, the first internal resistor and the second internal resistor are connected in parallel with each other and then connected in series with the gas sensing unit.

[0009] According to another embodiment of the present invention, the gas sensing device further comprises a third transistor. The third transistor is formed in the substrate and comprises a third gate terminal, a third drain terminal and a third source terminal. The second metal electrode layer is electrically connected to the third drain terminal.

[0010] According to one embodiment of the present invention, the gas sensing device further comprises a gas sensing unit, a first sub-sensing unit and a second sub-sensing unit. The gas sensing unit is composed of the interdigitated electrode and the second sensing material layer. The first sub-sensing unit is composed of the first transistor, the second transistor, the third transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer. The second sub-sensing unit is composed of an additional first transistor, the second transistor, the third transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer.

[0011] According to one embodiment of the present invention, the first metal electrode layer of the second sub-sensing unit is electrically connected to the third source terminal, and the second metal electrode layer of the second sub-sensing unit is electrically connected to the second source terminal. The first sub-sensing unit forms a first internal resistor, and the second sub-sensing unit forms a second internal resistor. The first drain terminal of the first sub-sensing unit and the first drain terminal of the second sub-sensing unit are both electrically connected to the gas sensing unit.

[0012] According to an embodiment of the present invention, when the second transistor of the first sub-sensing unit is turned on and the first transistor of the second sub-sensing unit is turned on, the first internal resistor, the second internal resistor and the gas sensing unit are connected in series.

[0013] According to another embodiment of the present invention, when the second transistor of the first sub-sensing unit is turned on, the third transistor of the first sub-sensing unit is turned on, and the first transistor of the second sub-sensing unit is turned on, the first internal resistor and the second internal resistor are connected in parallel to each other and then connected in series with the gas sensing unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a top view showing a sub-sensing unit according to an embodiment of the present invention;

[0015] Figure 2 is a cross-sectional view showing a sub-sensing unit according to an embodiment of the present invention;

[0016] Figure 3 is an equivalent circuit diagram showing a sub-sensing unit according to an embodiment of the present invention;

[0017] Figure 4 is an equivalent circuit diagram showing a gas sensing device according to an embodiment of the present invention;

[0018] Figure 5 is an equivalent circuit diagram showing a gas sensing device according to another embodiment of the present invention;

[0019] Figure 6 is a top view showing a sub-sensing unit according to another embodiment of the present invention;

[0020] Figure 7 is an equivalent circuit diagram showing a sub-sensing unit according to another embodiment of the present invention;

[0021] Figure 8 is an equivalent circuit diagram showing a gas sensing device according to another embodiment of the present invention;

[0022] Figure 9A-9E is a schematic diagram showing the operation of a gas sensing device according to another embodiment of the present invention;

[0023] Fig.10 is a schematic diagram showing a controller according to an embodiment of the present invention;

[0024] Fig.11 is a cross-sectional view showing a gas sensing device according to an embodiment of the present invention; and

[0025] Fig.12 FIG. 4 is a cross-sectional view showing a gas sensing device according to another embodiment of the present invention.

[0026] Figure Number:

[0027] 100,600: Sub-sensing unit

[0028] 400,500,800,1100,1200: Gas sensing device

[0029] 411,511,811,1111: first sub-sensing unit

[0030] 412,512,812,1112: second sub-sensing unit

[0031] 413,513,813,1113: third sub-sensing unit

[0032] 420,520,820: Gas sensing unit

[0033] 1000: Controller

[0034] 1120: interdigitated electrode

[0035] 1130: Second sensing material layer

[0036] 1240:Metal heating layer

[0037] T1: The first transistor

[0038] T2: Second transistor

[0039] T3: The third transistor

[0040] G1: first gate terminal

[0041] G2: Second gate terminal

[0042] G3: The third gate terminal

[0043] S1: First source terminal

[0044] S2: Second source terminal

[0045] S3: Third source terminal

[0046] D1: First drain terminal

[0047] D2: Second drain terminal

[0048] D3: The third drain terminal

[0049] M1: First metal electrode layer

[0050] M2: Second metal electrode layer

[0051] SM1: First sensing material layer

[0052] SUB:Substrate

[0053] R: Internal resistance

[0054] VS: Supply voltage

[0055] GND: Ground terminal

[0056] R1: First internal resistance

[0057] R2: Second internal resistance

[0058] R3: The third internal resistor

[0059] SG1: First signal

[0060] SG2: Second signal

[0061] SG3: Third signal

[0062] SG4: Fourth Signal

[0063] SG5: Fifth Signal

[0064] SG6: Sixth Signal

[0065] SG7: Seventh Signal

[0066] SG8: Eighth Signal

[0067] SG9: The Ninth Signal DETAILED DESCRIPTION

[0068] The following description is an embodiment of the present invention. Its purpose is to illustrate the general principles of the present invention and should not be regarded as limiting the present invention. The scope of the present invention should be based on the claims.

[0069] It is noteworthy that the content of the invention described below can provide multiple embodiments or examples for practicing the different features of the present invention. The special device examples and arrangements described below are only used to briefly and concisely explain the spirit of the present invention, and are not used to limit the scope of the present invention. In addition, the following description may reuse the same device symbols or text in multiple examples. However, the purpose of reusing is only to provide a simplified and clear description, and is not used to limit the relationship between multiple embodiments and / or configurations discussed below. In addition, the description of a feature connected to, coupled to, and / or formed on another feature described in the following description may actually include multiple different embodiments, including that the multiple features are in direct contact, or that other additional features are formed between the multiple features, etc., so that the multiple features are not in direct contact.

[0070] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used in the embodiments to describe the relative relationship of one device to another device in the figure. It is understood that if the device in the figure is turned upside down, the device described on the "lower" side will become the device on the "upper" side.

[0071] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various devices, components, regions, layers, and / or parts, these devices, components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different devices, components, regions, layers, and / or parts. Therefore, a first device, component, region, layer, and / or part discussed below may be referred to as a second device, component, region, layer, and / or part without departing from the teachings of some embodiments of the present invention.

[0072] Some embodiments of the present invention may be understood in conjunction with the drawings, and the drawings of the embodiments of the present invention are also considered as part of the description of the embodiments of the present invention. It should be understood that the drawings of the embodiments of the present invention are not drawn in proportion to the actual devices and components. The shapes and thicknesses of the embodiments may be exaggerated in the drawings to clearly show the features of the embodiments of the present invention. In addition, the structures and devices in the drawings are drawn in a schematic manner to clearly show the features of the embodiments of the present invention.

[0073] Here, the terms "about", "approximately" and "generally" generally mean within 20% of a given value or range, preferably within 10%, and more preferably within 5%, or within 3%, or within 2%, or within 1%, or within 0.5%. The numbers given here are approximate numbers, that is, in the absence of specific description of "about", "approximately" or "generally", the meanings of "about", "approximately" or "generally" can still be implied.

[0074] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as those commonly understood by those skilled in the art of this invention. It is understood that these terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the background or context of the relevant technology and the present invention, and should not be interpreted in an idealized or overly formal manner unless specifically defined in the embodiments of the present invention.

[0075] In some embodiments of the present invention, terms such as "connection" and "interconnection" may refer to two structures being in direct contact with each other, or two structures not being in direct contact with each other, with another structure disposed between the two structures, unless otherwise specified. Such terms may also include situations where both structures are movable or both structures are fixed.

[0076] Figure 1 FIG. 2 is a top view showing a sub-sensing unit according to an embodiment of the present invention. Figure 1 As shown, the sub-sensing unit 100 includes a first transistor T1 and a second transistor T2, wherein the first transistor T1 includes a first gate terminal G1, a first source terminal S1 and a first drain terminal D1, and the second transistor T2 includes a second gate terminal G2, a second source terminal S2 and a second drain terminal D2.

[0077] like Figure 1 As shown, the sub-sensing unit 100 further includes a first metal electrode layer M1, a first sensing material layer SM1 and a second metal electrode layer M2. The first metal electrode layer M1 is formed above the first transistor T1 and the second transistor T2, and the first metal electrode layer M1 is electrically connected to the first source terminal S1 and the second drain terminal D2. The first sensing material layer SM1 is formed between the first metal electrode layer M1 and the second metal electrode layer M2, and is electrically connected to the first metal electrode layer M1 and the second metal electrode layer M2. According to one embodiment of the present invention, the material of the first sensing material layer SM1 may include zinc oxide, molybdenum oxide, aluminum oxide, titanium oxide, tin oxide, tungsten oxide, but is not limited thereto.

[0078] Figure 2 is a cross-sectional view showing a sub-sensing unit according to an embodiment of the present invention, wherein Figure 2 Is displayed along Figure 1 The cross-sectional view of line AA'. Figure 2 As shown, the sub-sensing unit 100 further includes a substrate SUB, wherein the first transistor T1 and the second transistor T2 are both formed in the substrate SUB.

[0079] Figure 3 is an equivalent circuit diagram showing a sub-sensing unit according to an embodiment of the present invention, wherein Figure 3 Yes Display Figure 1 as well as Figure 2 The equivalent circuit of the sub-sensing unit 100 is shown in FIG. Figure 3 As shown, the first metal electrode layer M1 , the first sensing material layer SM1 and the second metal electrode layer M2 form an internal resistor R, and the first source terminal S1 and the second drain terminal D2 are electrically connected to the first metal electrode layer M1 .

[0080] Figure 4 is an equivalent circuit diagram showing a gas sensing device according to an embodiment of the present invention. Figure 4As shown, the gas sensing device 400 includes a first sub-sensing unit 411, a second sub-sensing unit 412, a third sub-sensing unit 413 and a gas sensing unit 420, wherein the first sub-sensing unit 411, the second sub-sensing unit 412 and the third sub-sensing unit 413 all correspond to Figure 3 The sub-sensing unit 100, and the top view and the cross-sectional view are respectively as shown Figure 1 as well as Figure 2 shown.

[0081] According to some embodiments of the present invention, the gas sensing device 400 may include any number of sub-sensing units, and the first sub-sensing unit 411, the second sub-sensing unit 412 and the third sub-sensing unit 413 are only used for explanation herein and are not limited thereto in any form.

[0082] like Figure 4 As shown, the second metal electrode layer M2 of the first sub-sensing unit 411 receives the supply voltage VS, the second source terminal S2 of the first sub-sensing unit 411 is electrically connected to the second metal electrode layer M2 of the second sub-sensing unit 412, and the second source terminal S2 of the second sub-sensing unit 412 is electrically connected to the second metal electrode layer M2 of the third sub-sensing unit 413. The gas sensing unit 420 is electrically connected between the first drain terminal D1 of the first sub-sensing unit 411, the second sub-sensing unit 412, and the third sub-sensing unit 413 and the ground terminal GND.

[0083] The first sub-sensing unit 411 is used to form a first internal resistor R1, the second sub-sensing unit 412 is used to form a second internal resistor R2, and the third sub-sensing unit 413 is used to form a third internal resistor R3. According to one embodiment of the present invention, when the first transistor T1 of the first sub-sensing unit 411 is turned on, the first internal resistor R1 and the gas sensing unit 420 are connected in series between the supply voltage VS and the ground terminal GND.

[0084] According to another embodiment of the present invention, when the second transistor T2 of the first sub-sensing unit 411 and the first transistor T1 of the second sub-sensing unit 412 are turned on, the first internal resistor R1, the second internal resistor R2 and the gas sensing unit 420 are connected in series between the supply voltage VS and the ground terminal GND.

[0085] According to another embodiment of the present invention, when the second transistor T2 of the first sub-sensing unit 411, the second transistor T2 of the second sub-sensing unit 412, and the first transistor T1 of the third sub-sensing unit 413 are turned on, the first internal resistor R1, the second internal resistor R2, the third internal resistor R3, and the gas sensing unit 420 are connected in series between the supply voltage VS and the ground terminal GND.

[0086] In other words, the gas sensing device 400 connects the first internal resistor R1, the second internal resistor R2 and the third internal resistor R3 in series with the gas sensing unit 420 through the first transistor T1 and the second transistor T2 of the first sub-sensing unit 411, the second sub-sensing unit 412 and the third sub-sensing unit 413. Furthermore, the first internal resistor R1, the second internal resistor R2 and the third internal resistor R3 are connected in series to form a resistance value matched with the gas sensing unit 420, thereby achieving the purpose of the ratio of the resistance value matched with the gas sensing unit 420 to be close to 1, and even compensating for the change of the resistance value caused by placing the gas sensing unit 420 in the package.

[0087] Figure 5 FIG. 2 is an equivalent circuit diagram of a gas sensing device according to another embodiment of the present invention. Figure 5 As shown, the gas sensing device 500 includes a first sub-sensing unit 511, a second sub-sensing unit 512, a third sub-sensing unit 513 and a gas sensing unit 520, wherein the first sub-sensing unit 511, the second sub-sensing unit 512 and the third sub-sensing unit 513 all correspond to Figure 3 The sub-sensing unit 100, and the top view and the cross-sectional view are respectively as shown Figure 1 as well as Figure 2 shown.

[0088] According to some embodiments of the present invention, the gas sensing device 500 may include any number of sub-sensing units, and the first sub-sensing unit 511, the second sub-sensing unit 512 and the third sub-sensing unit 513 are only used for explanation herein and are not limited thereto in any form.

[0089] like Figure 5 As shown, the second metal electrode layers M2 of the first sub-sensing unit 511, the second sub-sensing unit 512, and the third sub-sensing unit 513 are all electrically connected together and receive the supply voltage VS. The second source terminal S2 of the first sub-sensing unit 511 is electrically connected to the first metal electrode layer M1 of the second sub-sensing unit 512, and the second source terminal S2 of the second sub-sensing unit 512 is electrically connected to the first metal electrode layer M1 of the third sub-sensing unit 513.

[0090] The gas sensing unit 520 is electrically connected between the first drain terminal D1 and the ground terminal GND of the first sub-sensing unit 511, the second sub-sensing unit 512 and the third sub-sensing unit 513. The first sub-sensing unit 511 is used to form a first internal resistor R1, the second sub-sensing unit 512 is used to form a second internal resistor R2, and the third sub-sensing unit 513 is used to form a third internal resistor R3.

[0091] According to an embodiment of the present invention, when the first transistor T1 of the first sub-sensing unit 511 is turned on, the first internal resistor R1 and the gas sensing unit 520 are connected in series between the supply voltage VS and the ground terminal GND.

[0092] According to another embodiment of the present invention, when the second transistor T2 of the first sub-sensing unit 511 and the first transistor T1 of the second sub-sensing unit 512 are turned on, the first internal resistor R1 and the second internal resistor R2 are connected in parallel to each other and then connected in series with the gas sensing unit 520 between the supply voltage VS and the ground terminal GND.

[0093] According to another embodiment of the present invention, when the second transistor T2 of the first sub-sensing unit 511, the second transistor T2 of the second sub-sensing unit 512, and the first transistor T1 of the third sub-sensing unit 513 are turned on, the first internal resistor R1, the second internal resistor R2, and the third internal resistor R3 are connected in parallel to each other and then connected in series with the gas sensing unit 520 between the supply voltage VS and the ground terminal GND.

[0094] In other words, the gas sensing device 500 connects the first internal resistor R1, the second internal resistor R2 and the third internal resistor R3 in parallel through the first transistor T1 and the second transistor T2 of the first sub-sensing unit 511, the second sub-sensing unit 512 and the third sub-sensing unit 513, and then connects them in series with the gas sensing unit 520. Furthermore, by forming a resistance value matched with the gas sensing unit 520 through the parallel connection of the first internal resistor R1, the second internal resistor R2 and the third internal resistor R3, the ratio of the resistance value matched with the gas sensing unit 520 can be close to 1, and even the change of the resistance value caused by the gas sensing unit 520 being placed in the package can be compensated.

[0095] Figure 6 FIG. 2 is a top view showing a sub-sensing unit according to another embodiment of the present invention. Figure 6 The sub-sensing unit 600 and Figure 1 Compared with the sub-sensing unit 100, the sub-sensing unit 600 further includes a third transistor T3, wherein the third transistor T3 includes a third gate terminal G3, a third source terminal S3 and a third drain terminal D3, and the third drain terminal D3 is electrically connected to the second metal electrode layer M2. According to some embodiments of the present invention, the cross-sectional view of the sub-sensing unit 600 is similar to Figure 2 Similar, no need to repeat it here.

[0096] Figure 7 is an equivalent circuit diagram showing a sub-sensing unit according to another embodiment of the present invention, wherein Figure 7 Yes Display Figure 6 The equivalent circuit of the sub-sensing unit 600 is Figure 7 The sub-sensing unit 600 and Figure 3 Compared with the sub-sensing unit 100, the sub-sensing unit 600 further includes a third transistor T3, and the third drain terminal D3 is electrically connected to the second metal electrode layer M2.

[0097] Figure 8 FIG. 2 is an equivalent circuit diagram of a gas sensing device according to another embodiment of the present invention. Figure 8 As shown, the gas sensing device 800 includes a first sub-sensing unit 811, a second sub-sensing unit 812, a third sub-sensing unit 813 and a gas sensing unit 820, wherein the first sub-sensing unit 811, the second sub-sensing unit 812 and the third sub-sensing unit 813 all correspond to Figure 7 The sub-sensing unit 600 is shown in the top view. Figure 6 shown.

[0098] According to some embodiments of the present invention, the gas sensing device 800 may include any number of sub-sensing units, and the first sub-sensing unit 811, the second sub-sensing unit 812 and the third sub-sensing unit 813 are only used for illustration and are not limited in any form.

[0099] like Figure 8 As shown, the second metal electrode layer M2 of the first sub-sensing unit 811 receives the supply voltage VS. The second source terminal S2 of the first sub-sensing unit 811 is electrically connected to the second metal electrode layer M2 of the second sub-sensing unit 812, and the third source terminal S3 of the first sub-sensing unit 811 is electrically connected to the first metal electrode layer M1 of the second sub-sensing unit 812.

[0100] The second source terminal S2 of the second sub-sensing unit 812 is electrically connected to the second metal electrode layer M2 of the third sub-sensing unit 813, and the third source terminal S3 of the second sub-sensing unit 812 is electrically connected to the first metal electrode layer M1 of the third sub-sensing unit 813. The first drain terminal D1 of the first sub-sensing unit 811, the second sub-sensing unit 812, and the third sub-sensing unit 813 are all electrically connected to the gas sensing unit 820. The detailed operation of the gas sensing device 800 will be described in detail below.

[0101] Figure 9A-9E FIG. 2 is a schematic diagram showing the operation of a gas sensing device according to another embodiment of the present invention. Fig. 9A As shown, when the first transistor T1 of the first sub-sensing unit 811 is turned on, the first internal resistor R1 and the gas sensing unit 820 are connected in series between the supply voltage VS and the ground terminal GND.

[0102] like Fig. 9BAs shown, when the second transistors T2 of the first sub-sensing unit 811 and the second sub-sensing unit 812 and the first transistor T1 of the second sub-sensing unit 812 are turned on, the first internal resistor R1, the second internal resistor R2 and the gas sensing unit 820 are connected in series between the supply voltage VS and the ground terminal GND.

[0103] like Fig. 9C As shown, when the second transistors T2 of the first sub-sensing unit 811 and the second sub-sensing unit 812 and the first transistor T1 of the second sub-sensing unit 812 are turned on, the first internal resistor R1, the second internal resistor R2 and the gas sensing unit 820 are connected in series between the supply voltage VS and the ground terminal GND.

[0104] like Fig.9D As shown, when the first transistor T1, the second transistor T2 and the third transistor T3 of the first sub-sensing unit 811 are all turned on, the first internal resistor R1 and the second internal resistor R2 are connected in parallel and then connected in series with the gas sensing unit 820 between the supply voltage VS and the ground terminal GND. According to other embodiments of the present invention, the first transistor T1 of the second sub-sensing unit 812 can also be turned on at the same time.

[0105] like Fig.9E As shown, when the second transistor T2 and the third transistor T3 of the first sub-sensing unit 811 and the second sub-sensing unit and the first transistor T1 of the first sub-sensing unit 811 are all turned on, the first internal resistor R1, the second internal resistor R2 and the third internal resistor R3 are connected in parallel and then connected in series with the gas sensing unit 820 between the supply voltage VS and the ground terminal GND. According to other embodiments of the present invention, the first transistor T1 of the second sub-sensing unit 812 and / or the third sub-sensing unit 813 can also be turned on at the same time.

[0106] In other words, through the first transistor T1, the second transistor T2 and the third transistor T3 of the first sub-sensing unit 811, the second sub-sensing unit 812 and the third sub-sensing unit 813, the first internal resistor R1, the second internal resistor R2 and the third internal resistor R3 can be connected in series or in parallel to form a resistance value matched with the gas sensing unit 820, thereby achieving a ratio of the matched resistance value to the resistance value of the gas sensing unit 820 close to 1.

[0107] Fig.10 is a schematic diagram showing a controller according to an embodiment of the present invention. Fig.10 As shown, the controller 1000 is used to generate a first signal SG1 , a second signal SG2 , a third signal SG3 , a fourth signal SG4 , a fifth signal SG5 , a sixth signal SG6 , a seventh signal SG7 , an eighth signal SG8 and a ninth signal SG9 .

[0108] The first signal SG1, the second signal SG2, the third signal SG3, the fourth signal SG4, the fifth signal SG5, the sixth signal SG6, the seventh signal SG7, the eighth signal SG8 and the ninth signal SG9 are used to control Figure 8 The first transistor T1 , the second transistor T2 , and the third transistor T3 of the first sub sensing unit 811 , the second sub sensing unit 812 , and the third sub sensing unit 813 are turned on and off.

[0109] According to another embodiment of the present invention, the controller 1000 can also be used to control Figure 4 The first transistor T1, the second transistor T2 and the third transistor T3 of the first sub-sensing unit 411, the second sub-sensing unit 412 and the third sub-sensing unit 413 are turned on and off. According to another embodiment of the present invention, the controller 1000 can also control Figure 5 The first transistor T1 , the second transistor T2 , and the third transistor T3 of the first sub sensing unit 511 , the second sub sensing unit 512 , and the third sub sensing unit 513 are turned on and off.

[0110] Fig.11 FIG. 2 is a cross-sectional view showing a gas sensing device according to an embodiment of the present invention. Fig.11 As shown, the gas sensing device 1100 includes a first sub-sensing unit 1111 , a second sub-sensing unit 1112 , a third sub-sensing unit 1113 , an interdigitated electrode 1120 , and a second sensing material layer 1130 .

[0111] According to some embodiments of the present invention, the top view and the cross-sectional view of the first sub-sensing unit 1111, the second sub-sensing unit 1112 and the third sub-sensing unit 1113 are as follows: Figure 1 as well as Figure 2 As shown, the connection relationship can be as follows Figure 4 or Figure 5 According to another embodiment of the present invention, the top view of the first sub-sensing unit 1111, the second sub-sensing unit 1112 and the third sub-sensing unit 1113 can be as shown in FIG. Figure 6 As shown, the connection relationship can be as follows Figure 8 As shown, no further repetition is given here.

[0112] The interdigitated electrodes 1120 are formed on the first sub-sensing unit 1111, the second sub-sensing unit 1112, and the third sub-sensing unit 1113, and the second sensing material layer 1130 is formed on the interdigitated electrodes 1120. According to one embodiment of the present invention, the first sensing material layer SM1 and the second sensing material layer 1130 are made of the same material, which may include zinc oxide, molybdenum oxide, aluminum oxide, titanium oxide, tin oxide, or tungsten oxide.

[0113] Specifically, the interdigitated electrodes 1120 are formed at Figure 1 , Figure 2 , Figure 6 The first metal electrode layer M1, the first sensing material layer SM1 and the second metal electrode layer M2 are electrically connected to the first sub-sensing unit 1111, the second sub-sensing unit 1112, the first drain terminal D1 of the third sub-sensing unit 1113 and the ground terminal GND (shown in FIG. Figure 4 , Figure 5 , Figure 8 , and not shown in Fig.11 ).

[0114] Fig.12 FIG. 2 is a cross-sectional view showing a gas sensing device according to another embodiment of the present invention. Fig.12 The gas sensing device 1200 and Fig.11 Compared with the gas sensing device 1100 , the gas sensing device 1200 further includes a metal heating layer 1240 .

[0115] The metal heating layer 1240 is formed on the first sub-sensing unit 1111, the second sub-sensing unit 1112 and the third sub-sensing unit 1113, and the interdigitated electrode 1120 is formed on the metal heating layer 1240. In detail, the metal heating layer 1240 is disposed on Figure 1 , Figure 2 , Figure 6 The metal heating layer 1240 is formed on the first metal electrode layer M1, the first sensing material layer SM1 and the second metal electrode layer M2. According to some embodiments of the present invention, the material of the metal heating layer 1240 may include aluminum, gold or platinum. By integrating the metal heating layer 1240 into the gas sensing device 1200, the sensitivity of the second sensing material layer 1130 can be improved while taking into account the area after integration.

[0116] The gas sensing device and structure proposed by the present invention form a plurality of sub-sensing units below the main gas sensing unit, and utilize the series connection and parallel connection of the sub-sensing units to form a matching resistor with a resistance value substantially similar to the main gas sensing unit, so as to reduce the resolution requirement of the analog-to-digital converter. In addition, the series connection and parallel connection of the sub-sensing units can also be used to offset the change in the resistance value of the gas sensing unit caused by packaging, so that the matching resistance value is close to the resistance value of the main gas sensing unit, thereby reducing the resolution requirement of the analog-to-digital conversion circuit.

[0117] Although the embodiments of the present invention and their advantages have been disclosed as above, it should be understood that any person skilled in the art may make changes, substitutions and modifications without departing from the spirit and scope of the present invention. In addition, the scope of protection of the present invention is not limited to the manufacturing process, machine, manufacture, material composition, device, method and steps in the specific embodiments described in the specification. Any person skilled in the art can understand the current or future developed manufacturing process, machine, manufacture, material composition, device, method and steps from the disclosure of some embodiments of the present invention. As long as the same functions can be implemented in the embodiments described herein or the same results can be obtained, they can be used according to some embodiments of the present invention. Therefore, the scope of protection of the present invention includes the above-mentioned manufacturing process, machine, manufacture, material composition, device, method and steps. In addition, each claim constitutes an individual embodiment, and the scope of protection of the present invention also includes the combination of each claim and embodiment.

Claims

1. A gas sensing device, characterized in that: include: a substrate; A first transistor, formed in the substrate, and comprising a first gate terminal, a first drain terminal and a first source terminal; a second transistor formed in the substrate and comprising a second gate terminal, a second drain terminal and a second source terminal; a first metal electrode layer formed on the first transistor and the second transistor and electrically connected to the first source terminal and the second drain terminal; a second metal electrode layer formed on the first transistor and the second transistor; a first sensing material layer formed on the first metal electrode layer and the second metal electrode layer and electrically connected to the first metal electrode layer and the second metal electrode layer; an interdigitated electrode formed on the first metal electrode layer, the second metal electrode layer and the first sensing material layer; and A second sensing material layer is formed on the interdigitated electrodes.

2. The gas sensing device according to claim 1, characterized in that: Also includes: a metal heating layer formed on the first metal electrode layer, the second metal electrode layer and the sensing material layer; The interdigitated electrodes are formed on the metal heating layer; The metal heating layer is used to improve the sensitivity of the second sensing material.

3. The gas sensing device according to claim 1, characterized in that: Also includes: a gas sensing unit, consisting of the interdigitated electrodes and the second sensing material layer; and a first sub-sensing unit, consisting of the first transistor, the second transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer; wherein the interdigitated electrode is electrically connected to the first drain terminal; The first metal electrode layer, the first sensing material layer and the second metal electrode layer of the first sub-sensing unit form a first internal resistor; When the first transistor is turned on according to the signal received by the first gate terminal, the internal resistor of the gas sensing unit and the first sub-sensing unit are connected in series with the gas sensing unit.

4. The gas sensing device according to claim 3, characterized in that: Also includes: a second sub-sensing unit, consisting of the additional first transistor, the second transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer; wherein the first drain terminal of the second sub-sensing unit is electrically connected to the interdigitated electrode; wherein the first metal electrode layer, the first sensing material layer and the second metal electrode layer of the second sub-sensing unit form a second internal resistor; When the second transistor of the first sub-sensing unit is turned on and the first transistor of the second sub-sensing unit is turned on, the first internal resistor, the second internal resistor and the gas sensing unit are connected in series.

5. The gas sensing device according to claim 3, characterized in that: Also includes: a second sub-sensing unit, consisting of the additional first transistor, the second transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer; wherein the first metal electrode layer, the first sensing material layer and the second metal electrode layer of the second sub-sensing unit form a second internal resistor; wherein the second metal electrode layer of the first sub-sensing unit is electrically connected to the second metal electrode layer of the second sub-sensing unit, and the first metal electrode layer of the second sub-sensing unit is electrically connected to the second source terminal of the first sub-sensing unit; When the second transistor of the first sub-sensing unit is turned on and the first transistor of the second sub-sensing unit is turned on, the first internal resistor and the second internal resistor are connected in parallel and then connected in series with the gas sensing unit.

6. The gas sensing device according to claim 4, characterized in that: Also includes: a third transistor formed in the substrate and comprising a third gate terminal, a third drain terminal and a third source terminal; The second metal electrode layer is electrically connected to the third drain terminal.

7. The gas sensing device according to claim 6, characterized in that: Also includes: a gas sensing unit, consisting of the interdigitated electrodes and the second sensing material layer; a first sub-sensing unit, consisting of the first transistor, the second transistor, the third transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer; and A second sub-sensing unit is composed of the additional first transistor, the second transistor, the third transistor, the first metal electrode layer, the first sensing material layer and the second metal electrode layer.

8. The gas sensing device according to claim 7, characterized in that: The first metal electrode layer of the second sub-sensing unit is electrically connected to the third source terminal; wherein the second metal electrode layer of the second sub-sensing unit is electrically connected to the second source terminal; The first sub-sensing unit forms a first internal resistor; The second sub-sensing unit forms a second internal resistor; The first drain terminal of the first sub-sensing unit and the first drain terminal of the second sub-sensing unit are both electrically connected to the gas sensing unit.

9. The gas sensing device according to claim 8, characterized in that: When the second transistor of the first sub-sensing unit is turned on and the first transistor of the second sub-sensing unit is turned on, the first internal resistor, the second internal resistor and the gas sensing unit are connected in series.

10. The gas sensing device according to claim 8, characterized in that: When the second transistor of the first sub-sensing unit is turned on, the third transistor of the first sub-sensing unit is turned on, and the first transistor of the second sub-sensing unit is turned on, the first internal resistor and the second internal resistor are connected in parallel and then connected in series with the gas sensing unit.

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