A field-effect transistor gas sensor and its fabrication method
By employing a field-effect transistor-based gas sensor fabrication method and a heterojunction channel design, the problems of weak responsiveness in TMD-based gas sensors and poor stability in metal oxide-based gas sensors were solved, achieving high sensitivity and stable gas sensing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIASHAN FUDAN RESEARCH INSTITUTE
- Filing Date
- 2026-04-22
- Publication Date
- 2026-05-26
AI Technical Summary
Existing TMD-based gas sensors have weak responsiveness, while metal oxide-based gas sensors require high-temperature operation and are affected by humidity, resulting in poor sensitivity and stability. Changes in sensor resistance also affect sensor performance.
The gas sensor employs a field-effect transistor structure, which includes forming a dielectric layer, a source, and a drain on a substrate, and forming a two-dimensional material layer and an organic layer therebetween to form a channel of a heterojunction structure, which is controlled by using the substrate as the bottom gate.
It achieves stable and sensitive gas sensing with excellent electrical performance and operational stability, and improves gas response sensitivity.
Smart Images
Figure CN122084701A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a field-effect transistor gas sensor and its fabrication method. Background Technology
[0002] A gas sensor is a device that converts information such as gas composition and concentration into usable electrical signals.
[0003] Currently, organic semiconductor gas-sensitive materials are effectively applied in gas sensors due to their ability to bind gas molecules at ordered binding sites, feasible material control, high sensitivity, lightweight flexibility, diverse molecular designs, and biodegradability. Meanwhile, two-dimensional transition metal sulfide semiconductors (TMDs) have been extensively studied in the field of sensing technology due to their inherent two-dimensional properties and excellent material performance. Among them, gas sensors based on metal-doped TMDs or TMD / metal oxide heterojunctions have been developed to reduce the energy required for the reaction between TMDs and gas molecules, thereby improving gas absorption and sensing capabilities.
[0004] However, the exposed surface of a metal oxide (TMD) sensor exhibits relatively weak absorption for most gases, resulting in limited responsiveness. Furthermore, metal oxide-based gas sensors require relatively stringent environmental conditions during operation, typically necessitating higher operating temperatures to enhance their chemical reactivity with gases. This inevitably leads to increased energy consumption and baseline drift, making them unsuitable for everyday applications. Even though conductive polymers can be used as materials for gas sensing at room temperature, their performance is significantly affected by humidity, resulting in poor sensitivity, stability, and accuracy.
[0005] Furthermore, most gas sensors based on TMD or MOF (metal-organic framework) materials are resistive in nature, fabricated using a sandwich structure with upper and lower electrodes at both ends. When such sensors are exposed to chemical gases, charge exchange occurs between the gas and the functional layer material, causing changes in the sensor's resistance and current, thereby affecting the sensor's sensitivity, stability, and accuracy. Summary of the Invention
[0006] The purpose of this invention is to provide a field-effect transistor gas sensor and its fabrication method, so as to at least solve the problem of how to improve the sensitivity and operational stability of the gas sensor.
[0007] To solve the above-mentioned technical problems, the present invention provides a method for fabricating a field-effect transistor gas sensor, comprising: Provides a clean substrate; A dielectric layer is formed on the substrate; The source and drain are formed on the dielectric layer; A two-dimensional material layer is formed between the source and drain electrodes; Organic layers are formed on the source, drain, and two-dimensional material layers.
[0008] Optionally, in the method for fabricating the field-effect transistor gas sensor, the method for providing a clean substrate includes: Provide P-type heavily doped silicon substrates; The p-type heavily doped silicon substrate was cleaned sequentially with acetone, ethanol, and deionized water.
[0009] Optionally, in the method for fabricating the field-effect transistor gas sensor, the method for forming a dielectric layer on the substrate includes: A dielectric layer is formed on a substrate using chemical vapor deposition (CVD). When the dielectric layer is made of silicon oxide, the silicon oxide dielectric layer is grown on the substrate at 300°C using a CVD process with a gas ratio of 1:2 of Si₄H and N₂O. The thickness of the silicon oxide dielectric layer is 90 nm to 300 nm.
[0010] Optionally, in the method for fabricating the field-effect transistor gas sensor, the method for forming the source and drain on the dielectric layer includes: The source and drain regions are patterned and defined on the dielectric layer using photolithography etching. Using physical vapor deposition, source electrode material is deposited in the source region to form a source electrode, and drain electrode material is deposited in the drain region to form a drain electrode, wherein the thickness of the source electrode and the drain electrode is 50nm~80nm.
[0011] Optionally, in the method for fabricating the field-effect transistor gas sensor, the method for forming a two-dimensional material layer between the source and drain electrodes includes: A two-dimensional material layer is formed between the source and drain electrodes by mechanical stripping and positioning transfer, and the thickness of the two-dimensional material layer is 1nm~30nm.
[0012] Optionally, in the method for fabricating the field-effect transistor gas sensor, the method for forming an organic layer on the source, drain, and two-dimensional material layer includes: An organic layer is formed on the source electrode, drain electrode, and two-dimensional material layer using a vacuum thermal evaporation process. The thickness of the organic layer is 20 nm to 50 nm.
[0013] To address the aforementioned technical problems, the present invention also provides a field-effect transistor gas sensor, which is manufactured using the fabrication method of a field-effect transistor gas sensor as described in any of the preceding claims. The field-effect transistor gas sensor includes a substrate, a dielectric layer, a two-dimensional material layer, and an organic layer arranged sequentially from bottom to top. An active electrode and a drain electrode are formed on both sides of the two-dimensional material layer, respectively. The substrate serves as the bottom gate electrode, and the two-dimensional material layer and the organic layer serve as the channel of a heterojunction structure.
[0014] Optionally, in the field-effect transistor gas sensor, the substrate is a P-type heavily doped silicon substrate.
[0015] Optionally, in the field-effect transistor gas sensor, the dielectric layer is made of SiO2, HfO2, Al2O3, or ZrO2.
[0016] Optionally, in the field-effect transistor gas sensor, the two-dimensional material layer is made of a TMD group N-type two-dimensional semiconductor material.
[0017] Optionally, in the field-effect transistor gas sensor, the organic layer is made of a P-type organic semiconductor material.
[0018] Optionally, in the field-effect transistor gas sensor, the source electrode is made of metal, and the drain electrode is made of metal.
[0019] The present invention provides a field-effect transistor (FET) gas sensor and its fabrication method, comprising: providing a clean substrate; forming a dielectric layer on the substrate; forming a source and a drain on the dielectric layer; forming a two-dimensional material layer between the source and the drain; and forming an organic layer on the source, drain, and the two-dimensional material layer. The heterojunction channel formed by the two-dimensional material layer and the organic layer enables the gas sensor to achieve stable and sensitive gas sensing. Simultaneously, by using the substrate as the bottom gate, in conjunction with the source and drain, a gate-controlled gas response function can be achieved. Thus, the gas sensor possesses excellent electrical performance and operational stability while exhibiting superior gas response sensitivity, solving the problem of how to improve the sensitivity and operational stability of gas sensors. Attached Figure Description
[0020] Figure 1 A flowchart illustrating the fabrication method of the field-effect transistor gas sensor provided in this embodiment; Figures 2(A) to 2(E) are schematic diagrams of the structure of the field-effect transistor gas sensor in each step of the fabrication method of the field-effect transistor gas sensor provided in this embodiment; Figure 3 This is a schematic diagram of the structure of the field-effect transistor gas sensor provided in this embodiment; The labels in the attached figures are explained as follows: 100 - Substrate; 200 - Dielectric layer; 310 - Source; 320 - Drain; 400 - Two-dimensional material layer; 500 - Organic layer. Detailed Implementation
[0021] The field-effect transistor gas sensor and its fabrication method proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and use non-precise scales, used only to facilitate and clarify the illustration of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and sometimes use different scales.
[0022] It should be noted that the terms "first," "second," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects in order to describe embodiments of the invention, and are not used to describe a specific order or sequence. It should be understood that such uses of terminology are interchangeable where appropriate. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0023] Field-effect transistor gas sensors can adjust the carrier concentration in the channel by applying different voltages to the gate, thereby regulating the charge exchange efficiency between the gas and the channel, and thus achieving sensitivity adjustment of the gas sensor.
[0024] Based on this, this embodiment provides a method for fabricating a field-effect transistor type gas sensor, such as... Figure 1 As shown, it includes: S1 provides a clean substrate; S2, a dielectric layer is formed on the substrate; S3 forms the source and drain on the dielectric layer; S4, a two-dimensional material layer is formed between the source and drain; S5 forms an organic layer on the source, drain, and two-dimensional material layer.
[0025] The method for fabricating a field-effect transistor (FET) gas sensor provided in this embodiment utilizes a heterojunction channel formed by a two-dimensional material layer and an organic layer, enabling the gas sensor to achieve stable and sensitive gas sensing. Simultaneously, by using a substrate as the bottom gate, in conjunction with the source and drain, a gate-controlled gas response function is achieved. Thus, the gas sensor possesses excellent electrical performance and operational stability, while also exhibiting superior gas response sensitivity, solving the problem of how to improve the sensitivity and operational stability of gas sensors.
[0026] Specifically, in this embodiment, step S1, as shown in FIG2(A), provides a clean substrate 100. In practical applications, the substrate 100 can be a p-type heavily doped silicon substrate, such as a boron heavily doped silicon substrate, so that the substrate 100, as the back gate electrode of a field-effect transistor gas sensor, can effectively control the electrical performance and gas response function of the gas sensor.
[0027] Preferably, in order to ensure the stability of subsequent structure formation and the tightness of contact with the gate, in this embodiment, the substrate is cleaned sequentially with acetone, ethanol and deionized water to provide a clean substrate.
[0028] Furthermore, in this embodiment, step S2, as shown in FIG2(B), involves forming a dielectric layer 200 on the substrate 100. Specifically, in practical applications, a chemical vapor deposition (PECVD) process can be used to form the dielectric layer 200 on the substrate 100. In this way, a dielectric layer 200 with high conformality and high quality can be obtained.
[0029] In practical applications, the dielectric layer 200 can be made of SiO2, HfO2, Al2O3 or ZrO2.
[0030] When the dielectric layer 200 is made of silicon oxide, a silicon oxide dielectric layer is grown on the substrate at 300°C using a chemical vapor deposition process with a gas ratio of 1:2 of Si4H and N2O. The thickness of the silicon oxide dielectric layer is 90nm~300nm.
[0031] Of course, those skilled in the art can learn how to form dielectric layers 200 of other materials on substrate 100 based on existing technology, and this application will not elaborate on this further. When forming dielectric layers 200 of HfO2, Al2O3 or ZrO2, the thickness of dielectric layer 200 is 15nm~30nm.
[0032] Furthermore, in this embodiment, step S3, as shown in FIG2(C), involves forming a source electrode 310 and a drain electrode 320 on the dielectric layer 200. Specifically, in this embodiment, firstly, the source electrode region and the drain electrode region are patterned and defined on the dielectric layer 200 using a photolithography etching process, such as ultraviolet lithography; then, a physical vapor deposition (PVD) process is used to deposit source electrode material in the source electrode region to form the source electrode 310, and to deposit drain electrode material in the drain electrode region to form the drain electrode 320. Using this method to prepare the source and drain electrodes results in a simple process, low cost, and high yield.
[0033] In practical applications, both the source electrode 310 and the drain electrode 320 are made of metal. The metal can be selected from metals with good electrical conductivity, such as Au, Pt, Ag, and Al. Furthermore, the thickness of both the source electrode 310 and the drain electrode 320 is 50 nm to 80 nm.
[0034] To simplify the process, the source 310 and drain 320 can be formed simultaneously, that is, the same metal material is used to form the source 310 and drain 320 of the same thickness.
[0035] Furthermore, in this embodiment, step S4, as shown in FIG2(D), involves forming a two-dimensional material layer 400 between the source electrode 310 and the drain electrode 320. Specifically, in this embodiment, the two-dimensional material layer 400 can be formed between the source electrode 310 and the drain electrode 320 by mechanical peeling and positioning transfer methods.
[0036] In practical applications, the two-dimensional material layer 400 is made of a TMD group N-type two-dimensional semiconductor material, such as molybdenum disulfide (MoS2), tungsten disulfide (WS2), molybdenum diselenide (MoSe2), molybdenum distelluride (MoTe2), rhenium disulfide (ReS2), etc. Furthermore, the thickness of the two-dimensional material layer 400 is 1 nm to 30 nm.
[0037] Furthermore, in this embodiment, step S5, as shown in FIG2(E), involves forming an organic layer 500 on the source electrode 310, drain electrode 320, and two-dimensional material layer 400. Specifically, in this embodiment, a vacuum thermal evaporation process can be used to form the organic layer 500 on the source electrode 310, drain electrode 320, and two-dimensional material layer 400, wherein the vacuum degree is 10. -6 .
[0038] In practical applications, the organic layer 500 is made of a P-type organic semiconductor material, such as pentaphenyl, tetraphenyl, C8-BTBT (2,7-dioctyl[1]benzothiophene[3,2-b][1]benzothiophene), DNTT (dinaphtho[2,3-b:2',3'-f]thiophene[3,2-b]thiophene), P3HT (poly(3-hexylthiophene)), etc. The thickness of the organic layer 500 is 20 nm to 50 nm.
[0039] Thus, using the two-dimensional material layer 400 and the organic layer 500 as the channel of the heterojunction structure can balance the excellent electrical performance of the device with improved gas response sensitivity.
[0040] The fabrication method of the field-effect transistor gas sensor provided in this embodiment is achieved using a multilayer structure manufacturing process, which is easy to mass-produce. The fabrication method of the field-effect transistor gas sensor provided in this embodiment uses existing mature processes, such as cleaning, chemical vapor deposition, ultraviolet lithography, physical vapor deposition, mechanical stripping-positioning transfer, and vacuum thermal evaporation, which can achieve high-quality device fabrication at a relatively low process cost.
[0041] This embodiment also provides a field-effect transistor gas sensor, which is manufactured using the method described above for preparing a field-effect transistor gas sensor. Figure 3 As shown, the field-effect transistor gas sensor includes a substrate 100, a dielectric layer 200, a two-dimensional material layer 400, and an organic layer 500 arranged sequentially from bottom to top; an active electrode 310 and a drain electrode 320 are formed on both sides of the two-dimensional material layer 400, the substrate 100 serves as the bottom gate, and the two-dimensional material layer 400 and the organic layer 500 serve as the channel of the heterojunction structure.
[0042] The field-effect transistor gas sensor provided in this embodiment utilizes a heterojunction channel formed by a two-dimensional material layer 400 and an organic layer 500, enabling stable and sensitive gas sensing. Simultaneously, the substrate 100 serves as the bottom gate, which, in conjunction with the source 310 and drain 320, achieves gate-controlled gas response. Thus, the gas sensor possesses excellent electrical performance and operational stability, along with superior gas response sensitivity, solving the problem of how to improve the sensitivity and operational stability of gas sensors.
[0043] Specifically, in this embodiment, the substrate 100 can be a P-type heavily doped silicon substrate, such as a boron heavily doped silicon substrate. In this way, the substrate 100, as the back gate electrode of the field-effect transistor gas sensor, can effectively regulate the electrical performance and gas response function of the gas sensor.
[0044] Furthermore, in this embodiment, the dielectric layer 200 can be made of SiO2, HfO2, Al2O3, or ZrO2. When the dielectric layer 200 is made of silicon oxide, the thickness of the silicon oxide dielectric layer is 90 nm to 300 nm. When the dielectric layer 200 is made of HfO2, Al2O3, or ZrO2, the thickness of the dielectric layer 200 is 15 nm to 30 nm.
[0045] Furthermore, in this embodiment, both the source electrode 310 and the drain electrode 320 are made of metal. The metal can be selected from metals with good electrical conductivity such as Au, Pt, Ag, and Al. The thickness of both the source electrode 310 and the drain electrode 320 is 50 nm to 80 nm.
[0046] To reduce process complexity and save manufacturing costs, the source 310 and drain 320 can be made of the same metal material and have the same thickness.
[0047] Furthermore, in this embodiment, the two-dimensional material layer 400 is made of a TMD group N-type two-dimensional semiconductor material, such as molybdenum disulfide (MoS2), tungsten disulfide (WS2), molybdenum diselenide (MoSe2), molybdenum distelluride (MoTe2), rhenium disulfide (ReS2), etc. The thickness of the two-dimensional material layer 400 is 1 nm to 30 nm.
[0048] Furthermore, in this embodiment, the organic layer 500 is made of a P-type organic semiconductor material, such as pentaphenyl, tetraphenyl, C8-BTBT (2,7-dioctyl[1]benzothiophene[3,2-b][1]benzothiophene), DNTT (dinaphtho[2,3-b:2',3'-f]thiophene[3,2-b]thiophene), P3HT (poly(3-hexylthiophene)), etc. The thickness of the organic layer 500 is 20 nm to 50 nm.
[0049] Thus, using the two-dimensional material layer 400 and the organic layer 500 as the channel of the heterojunction structure can balance the excellent electrical performance of the device with improved gas response sensitivity.
[0050] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In addition, different parts between embodiments can also be combined with each other, and this invention does not limit this.
[0051] This embodiment provides a field-effect transistor (FET) gas sensor and its fabrication method, comprising: providing a clean substrate; forming a dielectric layer on the substrate; forming a source and a drain on the dielectric layer; forming a two-dimensional material layer between the source and drain; and forming an organic layer on the source, drain, and two-dimensional material layer. The heterojunction channel formed by the two-dimensional material layer and the organic layer enables the gas sensor to achieve stable and sensitive gas sensing. Simultaneously, by using the substrate as the bottom gate, in conjunction with the source and drain, a gate-controlled gas response function can be achieved. Thus, the gas sensor possesses excellent electrical performance and operational stability while exhibiting superior gas response sensitivity, solving the problem of how to improve the sensitivity and operational stability of gas sensors.
[0052] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.
Claims
1. A method for fabricating a field-effect transistor type gas sensor, characterized in that, include: Provides a clean substrate; A dielectric layer is formed on the substrate; The source and drain are formed on the dielectric layer; A two-dimensional material layer is formed between the source and drain electrodes; Organic layers are formed on the source, drain, and two-dimensional material layers.
2. The method for fabricating a field-effect transistor gas sensor according to claim 1, characterized in that, The method for providing a clean substrate includes: Provide P-type heavily doped silicon substrates; The p-type heavily doped silicon substrate was cleaned sequentially with acetone, ethanol, and deionized water.
3. The method for fabricating a field-effect transistor gas sensor according to claim 1, characterized in that, The method for forming a dielectric layer on a substrate includes: A dielectric layer is formed on a substrate using a chemical vapor deposition process.
4. The method for fabricating a field-effect transistor gas sensor according to claim 1, characterized in that, The method for forming source and drain electrodes on the dielectric layer includes: The source and drain regions are patterned and defined on the dielectric layer using photolithography etching. Using physical vapor deposition, source electrode material is deposited in the source region to form a source electrode, and drain electrode material is deposited in the drain region to form a drain electrode, wherein the thickness of the source electrode and the drain electrode is 50nm~80nm.
5. The method for fabricating a field-effect transistor gas sensor according to claim 1, characterized in that, The method for forming a two-dimensional material layer between the source and drain electrodes includes: A two-dimensional material layer is formed between the source and drain electrodes by mechanical stripping and positioning transfer, and the thickness of the two-dimensional material layer is 1nm~30nm.
6. The method for fabricating a field-effect transistor gas sensor according to claim 1, characterized in that, The method for forming an organic layer on the source, drain, and two-dimensional material layer includes: An organic layer is formed on the source electrode, drain electrode, and two-dimensional material layer using a vacuum thermal evaporation process. The thickness of the organic layer is 20 nm to 50 nm.
7. A field-effect transistor gas sensor, manufactured using the method for preparing a field-effect transistor gas sensor as described in any one of claims 1 to 6, characterized in that, The field-effect transistor gas sensor includes a substrate, a dielectric layer, a two-dimensional material layer, and an organic layer arranged sequentially from bottom to top; an active electrode and a drain electrode are formed on both sides of the two-dimensional material layer, the substrate serves as the bottom gate, and the two-dimensional material layer and the organic layer serve as the channel of the heterojunction structure.
8. The field-effect transistor gas sensor according to claim 7, characterized in that, The substrate is a P-type heavily doped silicon substrate.
9. The field-effect transistor gas sensor according to claim 7, characterized in that, The dielectric layer is made of SiO2, HfO2, Al2O3 or ZrO2.
10. The field-effect transistor gas sensor according to claim 7, characterized in that, The material of the two-dimensional material layer is a TMD family N-type two-dimensional semiconductor material.
11. The field-effect transistor gas sensor according to claim 7, characterized in that, The organic layer is made of a P-type organic semiconductor material.
12. The field-effect transistor gas sensor according to claim 7, characterized in that, The source electrode is made of metal, and the drain electrode is made of metal.