TWI891336B - Gas sensor - Google Patents

Abstract

The present invention relates to a gas sensor which has a first insulating layer at the upper end of a bracket, the first insulating layer is elevated by the bracket so that a heat dissipation space is formed between the bracket and the first insulating layer, a dielectric layer is disposed on the upper end of the first insulating layer, a second insulating layer is provided outside the upper end of the dielectric layer, a heating element is provided in the second insulating layer, a sensing layer is provided in the second insulating layer, an electrode is provided in the sensing layer, and a third insulating layer is provided at the upper end of the sensing layer. Accordingly, it not only achieves the heat dissipation effect on the heating element through the heat dissipation space during the heating process, but also has a protective effect on the sensing layer, which can avoid damage and failure of the sensing layer, and at the same time, it can increase the adsorption of oxygen molecules, thereby increasing the gas response and adding practical functional characteristics in its overall implementation.

Description

Gas Sensor

The present invention relates to a gas sensor, particularly one that not only dissipates heat from a heating element through a heat dissipation space, but also protects the sensing layer, preventing damage and failure. Furthermore, the sensor increases oxygen molecule adsorption, thereby enhancing gas response, thereby enhancing overall practical performance.

With the commercialization and industrialization of society, air quality has been significantly impacted by factors such as increased emissions from vehicles and factories. For example, exhaust gases from petrochemicals, battery plants, fluorescent lamp manufacturers, coal-fired power plants, and motorcycles include ammonia, fluorine, lead vapor, mercury vapor, carbon monoxide, nitrogen oxides, and sulfur dioxide. Furthermore, industrial emissions of carbon dioxide, carbon disulfide, hydrogen sulfide, fluorides, nitrogen oxides, chlorides, carbon monoxide, and fine dust particles pollute the air. These harmful substances can enter the human respiratory tract through various pathways and remain in the body, some causing direct harm, while others accumulate in the body and, in severe cases, can even cause direct and fatal harm.

Generally speaking, hydrogen sulfide is commonly found in gases used in industry, exhaust fumes, and waste, and can also appear in daily life due to certain industrial operations. Hydrogen sulfide, in particular, is an asphyxiant. Although it has a strong pungent odor that can startle people and drive them away, excessive concentrations can paralyze the olfactory nerves in a short period of time, placing people in danger without realizing it.

In addition, carbon monoxide is a gas that people need to pay more attention to and control its concentration in their daily lives. Since carbon monoxide is a colorless and odorless chemical substance produced by incomplete combustion of carbon-containing substances, incomplete combustion of natural gas or incomplete combustion of motorcycle exhaust in people's daily lives will cause people to be exposed to carbon monoxide in their living environment. Carbon monoxide is produced by Carbon monoxide's affinity for hemoglobin is two to three hundred times higher than oxygen's affinity for hemoglobin. Therefore, when a person inhales carbon monoxide, it competes with oxygen in the body for the opportunity to bind to hemoglobin, replacing oxygen and binding to hemoglobin. This causes the oxygen content in the blood to decrease, causing people to gradually lose consciousness and fall into a coma without realizing it, and eventually die from heart and brain damage.

Consequently, a variety of gas sensors are available on the market for detecting gas concentrations. Yole Development International estimated in 2018 that the value of gas sensors would increase from US$800 million in 2018 to over US$1 billion by 2023, with the vast majority used in mobile devices. However, integration into mobile devices requires miniaturization and low power consumption. Currently, only semiconductor chip-based gas sensors developed using microelectromechanical systems (MEMS) technology can achieve this miniaturization, minimal power consumption, and low cost, attracting considerable attention.

The gas detector microstructure of this type of micro-electromechanical system [MEMS] structure is commonly seen; please refer to the announcement No. I744831 on November 1, 2011, "Nanometal Hybrid Nanoparticle Catalyst Enhanced Gas Sensor", which mainly includes a bracket, an insulating layer, a dielectric layer, a heating element, a nanosensing layer and an electrode; Middle: The insulating layer is located on the upper end of the bracket, the dielectric layer is located on the outer side of the upper end of the insulating layer, the heating element is located within the dielectric layer, and the nanosensing layer is located between the dielectric layers. The electrode is located within the nanosensing layer. The nanosensing layer is composed of multiple nano-metal mixed nanoparticles and has a loose structure.

However, in actual operation, it was found that when the sensor is not heated by the heating element, only a small amount of gas will be present on the surface of the nano-sensing layer. Adsorption, and when adsorbed on the surface of the nanosensing layer, the That is, it will capture the electrons on the surface of the nanosensing layer and form , as shown below:

,

[150°C~300°C].

In contrast, even though the nanosensing layer loses electrons, resulting in an increase in the depletion region, a decrease in carrier flow, and an increase in impedance, its overall detection performance decreases, leaving room for improvement in its overall structural design.

Therefore, in view of this, the inventor, with his rich experience in design, development and actual manufacturing in the related industry over the years, has conducted research and improvements to address the existing deficiencies, and provides a gas sensor with greater practical value.

The primary objective of this invention is to provide a gas sensor that not only dissipates heat from the heating element through a heat dissipation space, but also protects the sensing layer, preventing damage and failure. Furthermore, it increases the adsorption of oxygen molecules, thereby enhancing the gas response, thereby enhancing its overall practical performance.

The main purpose and function of the gas sensor of this invention are achieved by the following specific technical means:

It mainly includes a bracket, a first insulating layer, a dielectric layer, a second insulating layer, a heating element, a sensing layer, an electrode and a third insulating layer; wherein:

The first insulating layer is provided at the upper end of the bracket. The first insulating layer is elevated by the bracket to form a heat dissipation space between the bracket and the first insulating layer. The dielectric layer is provided at the upper end of the first insulating layer. The second insulating layer is provided on the outer side of the upper end of the dielectric layer. The heating element is provided in the second insulating layer. The sensing layer is provided between the second insulating layers. The electrode is provided in the sensing layer. The third insulating layer is provided at the upper end of the sensing layer.

Another purpose and effect of the gas sensor of the present invention is achieved by the following specific technical means:

It mainly includes a bracket, a first insulating layer, a dielectric layer, a second insulating layer, a heating element, a sensing layer, an electrode and a third insulating layer; wherein:

The first insulating layer is provided on the upper end of the bracket. The first insulating layer is elevated by the bracket to form a heat dissipation space between the bracket and the first insulating layer. The dielectric layer is provided on the upper end of the first insulating layer. The second insulating layer is provided on the outer side of the upper end of the dielectric layer. The heating element is provided in the second insulating layer. The sensing layer is provided between the second insulating layers. The electrode is provided in the sensing layer. The third insulating layer is provided between the second insulating layer and the upper end of the sensing layer.

Another purpose and effect of the gas sensor of the present invention is achieved by the following specific technical means:

It mainly includes a bracket, a first insulating layer, a dielectric layer, a second insulating layer, a heating element, a sensing layer, an electrode and a third insulating layer; wherein:

The first insulating layer is provided on the upper end of the bracket. The first insulating layer is elevated by the bracket to form a heat dissipation space between the bracket and the first insulating layer. The dielectric layer is provided on the upper end of the first insulating layer. The second insulating layer is provided on the upper end of the dielectric layer. The heating element is provided in the second insulating layer. The sensing layer is provided on the upper end of the second insulating layer. The electrode is provided in the sensing layer. The third insulating layer is provided on the upper end of the sensing layer.

In a preferred embodiment of the gas sensor of the present invention, the first insulating layer is any one of silicon oxide [SiO ₂ ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], and silicon nitride [SiN _x ], and the thickness of the first insulating layer is 10 nm to 1000 nm.

In a preferred embodiment of the gas sensor of the present invention, the dielectric layer is any one of silicon nitride [SiN _x ], aluminum oxide [Al ₂ O ₃ ], and aluminum nitride [AlN].

In a preferred embodiment of the gas sensor of the present invention, the second insulating layer is any one of silicon oxide [SiO ₂ ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], and silicon nitride [SiN _x ], and the thickness of the second insulating layer is 10 nm to 300 nm.

In a preferred embodiment of the gas sensor of the present invention, the sensing layer is any one of a metal sulfide semiconductor, a metal oxysulfide semiconductor, and a metal oxide semiconductor, and the thickness of the sensing layer is 50nm-500nm.

In a preferred embodiment of the gas sensor of the present invention, the sensing layer is any one of zinc sulfide [ZnS] semiconductor, tin sulfide [SnS ₂ ] semiconductor, copper sulfide [CuS] semiconductor, iron sulfide [Fe ₂ S ₃ ] semiconductor, tungsten sulfide [WS 3 ] semiconductor, and titanium sulfide [TiS 2 ] semiconductor.

In a preferred embodiment of the gas sensor of the present invention, the sensing layer is any one of zinc oxysulfide [ZnSO ₄ ] semiconductor, tin oxysulfide [SnSO ₄ ] semiconductor, copper oxysulfide [CuSO ₄ ] semiconductor, iron oxysulfide [FeSO ₄ ] semiconductor, and titanium oxysulfide [TiOSO ₄ ] semiconductor.

In a preferred embodiment of the gas sensor of the present invention, the sensing layer is any one of zinc oxide [ZnO] semiconductor, tin dioxide [SnO ₂ ] semiconductor, copper oxide [CuO] semiconductor, ferric oxide [Fe ₂ O ₃ ] semiconductor, tungsten oxide [WO ₃ ] semiconductor, and titanium dioxide [TiO ₂ ] semiconductor.

In a preferred embodiment of the gas sensor of the present invention, the third insulating layer is any one of silicon oxide [SiO ₂ ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], and silicon nitride [SiN _x ], and has a thickness of 10 nm to 300 nm.

To provide a more complete and clear disclosure of the technical content, purpose of the invention, and the effects achieved by the present invention, the following is a detailed description thereof, and please refer to the accompanying drawings and figure numbers:

First, please refer to the first figure for a schematic diagram of the structure of the present invention. The present invention mainly includes a bracket (1), a first insulating layer (2), a dielectric layer (3), a second insulating layer (4), a heating element (5), a sensing layer (6), an electrode (7) and a third insulating layer (8); wherein:

The first insulating layer (2) is provided on the upper end of the support (1). The first insulating layer (2) is raised by the support (1) so that a heat dissipation space (11) is formed between the support (1) and the first insulating layer (2). The first insulating layer (2) can be any one of silicon oxide [SiO ₂ ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], and silicon nitride [SiN _x ], and the thickness of the first insulating layer (2) is 10nm~1000nm. The dielectric layer (3) is provided on the upper end of the first insulating layer (2). The dielectric layer (3) can be any one of silicon nitride [SiN _x ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], the second insulating layer (4) is provided on the outer side of the upper end of the dielectric layer (3), the second insulating layer (4) can be any one of silicon oxide [SiO ₂ ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], silicon nitride [SiN _x ], and the thickness of the second insulating layer (4) is 10nm~300nm, the heating element (5) is provided in the second insulating layer (4), and the sensing layer (6) is provided between the second insulating layer (4), and the sensing layer (6) can be a metal sulfide semiconductor, such as zinc sulfide [ZnS] semiconductor, tin sulfide [SnS ₂ ] semiconductor, copper sulfide [CuS] semiconductor, iron sulfide [Fe ₂ S ₃ ] semiconductor, tungsten sulfide [WS ₃ ] semiconductor, titanium sulfide [TiS ₂ ] semiconductor, or the sensing layer (6) can be a metal sulfide semiconductor, such as zinc oxysulfide [ZnSO ₄ ] semiconductor, tin oxysulfide [SnSO ₄ ] semiconductor, copper oxysulfide [CuSO ₄ ] semiconductor, iron sulfide [FeSO ₄ ] semiconductor, titanium oxysulfide [TiOSO ₄ ] semiconductor, or the sensing layer (6) can be a metal oxide semiconductor, such as zinc oxide [ZnO] semiconductor, tin dioxide [SnO ₂ ］ semiconductor, copper oxide [CuO] semiconductor, ferric oxide [Fe ₂ O ₃ ] semiconductor, tungsten oxide [WO ₃ ] semiconductor, titanium dioxide [TiO ₂ ] semiconductor, and the thickness of the sensing layer (6) is 50nm~500nm, the electrode (7) is provided in the sensing layer (6), and the third insulating layer (8) is provided on the upper end of the sensing layer (6), the third insulating layer (8) can be any one of silicon oxide [SiO ₂ ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], silicon nitride [SiN _x ], and the thickness of the third insulating layer (8) is 10nm~300nm.

In addition, please refer to the second figure for another embodiment of the present invention. As shown in the schematic diagram, the third insulating layer (8) can also be arranged on the upper end of the second insulating layer (4) and the sensing layer (6).

In addition, please refer to the third figure for another embodiment of the present invention. The first insulating layer (2) can be provided on the upper end of the bracket (1), and the dielectric layer (3) can be provided on the upper end of the first insulating layer (2). Then, the second insulating layer (4) can be provided on the upper end of the dielectric layer (3), the heating element (5) can be provided in the second insulating layer (4), the sensing layer (6) can be provided on the upper end of the second insulating layer (4), the electrode (7) can be provided in the sensing layer (6), and the third insulating layer (8) can be provided on the upper end of the sensing layer (6).

In this way, the present invention utilizes the heat dissipation space (11) formed between the bracket (1) and the first insulating layer (2) during operation, so that during the heating process of the heating element (5), the heat dissipation effect can be achieved through the heat dissipation space (11). Moreover, since the sensing layer (6) is a metal sulfide semiconductor or a metal oxysulfide semiconductor, it has already presented a stable sulfurization state, so that the sensing layer (6) can be prevented from being oxidized again during the sensing process. The third insulating layer (8) can protect the sensing layer (6) and prevent the sensing layer (6) from being damaged, failing or mis-sensing. Due to the difference in the energy gap structure between the sensing layer (6) and the third insulating layer (8), a two-dimensional electron gas is generated at the interface between the sensing layer (6) and the third insulating layer (8). electron gas, 2DEG] structure, at this time, the electrons will be confined at the interface between the sensing layer (6) and the third insulating layer (8), and will produce a similar electric field effect with the oxygen molecules adsorbed on the surface, increasing the adsorption of oxygen molecules, and then increasing the gas response, such as: when the sensing layer (6) is a tin sulfide [SnS ₂ ] semiconductor [please refer to the fourth figure of the present invention for the gas response diagram of the sensing layer of the tin sulfide [SnS ₂ ] semiconductor], or when the sensing layer (6) is a tin dioxide [SnO ₂ ] semiconductor plus a tin sulfide [SnS ₂ ] semiconductor [please refer to the fifth figure of the present invention for the gas response diagram of the tin dioxide [SnO ₂ ］semiconductor plus tin sulfide [SnS ₂ ] semiconductor's sensing layer gas response diagram].

In addition, please refer to the sixth figure of the gas response diagram of the best embodiment of the present invention. When the third insulating layer (8) is silicon nitride [ _SiNx ] and the sensing layer (6) is tin dioxide [ _SnO2 ], the gas response measured on February 29, 2024 is very close to the gas response measured on March 15, 2024, 15 days later, making it most stable when the third insulating layer (8) is silicon nitride [ _SiNx ] and the sensing layer (6) is tin dioxide [ _SnO2 ].

When the temperature is heated to above 150°C by the heating element (5), the oxygen absorption capacity of the surface of the sensing layer (6) is improved, and more Adsorbed on the third insulating layer (8), it will capture the electrons on the surface of the sensing layer (6) to form , when the temperature rises above 300°C, Electron formation on the absorbing surface . Please refer to the following formula:

[150°C~300°C],

［＞300°C］.

From the above description of the composition and practical application of the present invention, it can be seen that, compared to existing structures, the present invention not only achieves heat dissipation during the heating process of the heating element through the heat dissipation space, but also has a protective effect on the sensing layer, preventing damage and failure of the sensing layer. It also increases the adsorption of oxygen molecules, thereby increasing the gas response, and its overall practical performance characteristics are further enhanced.

However, the aforementioned embodiments or drawings do not limit the product structure or usage of the present invention. Any appropriate changes or modifications by those skilled in the art should be considered as falling within the patent scope of the present invention.

In summary, the embodiments of this invention can indeed achieve the intended effects. Moreover, the specific structure disclosed therein is not only unprecedented in similar products, but has also not been disclosed prior to the filing of this application. Therefore, this invention fully complies with the provisions and requirements of the Patent Law. Therefore, we hereby file an application for an invention patent in accordance with the law and earnestly request your review and the granting of the patent. We would be grateful for your kindness.

1: Bracket 11: Heat dissipation space 2: First insulation layer 3: Dielectric layer 4: Second insulation layer 5: Heating element 6: Sensing layer 7: Electrode 8: Third insulation layer

Figure 1: Schematic diagram of the structure of the present invention. Figure 2: Schematic diagram of the structure of another embodiment of the present invention. Figure 3: Schematic diagram of the structure of yet another embodiment of the present invention. Figure 4: Gas response diagram of the sensing layer of the tin sulfide [SnS ₂ ] semiconductor of the present invention. Figure 5: Gas response diagram of the sensing layer of the tin dioxide [SnO ₂ ] semiconductor plus the tin sulfide [SnS ₂ ] semiconductor of the present invention. Figure 6: Gas response diagram of the best embodiment of the present invention.

1: Bracket

11: Heat dissipation space

2: First insulating layer

3: Dielectric layer

4: Second insulating layer

5: Heating element

6: Sensing layer

7: Electrode

8: Third insulating layer

Claims (5)

A gas sensor mainly includes a bracket, a first insulating layer, a dielectric layer, a second insulating layer, a heating element, a sensing layer, an electrode, and a third insulating layer; wherein: The first insulating layer is provided on the upper end of the bracket. The first insulating layer is raised by the bracket so that a heat dissipation space is formed between the bracket and the first insulating layer. The dielectric layer is provided on the upper end of the first insulating layer. The second insulating layer is provided on the outer side of the upper end of the dielectric layer. The heating element is provided in the second insulating layer. The sensing layer is provided between the second insulating layers. The sensing layer is tin dioxide [SnO ₂ ］semiconductor, the electrode is provided in the sensing layer, and the third insulating layer is provided on the second insulating layer and the upper end of the sensing layer. The third insulating layer is silicon nitride [SiN _x ], and the thickness of the third insulating layer is 10nm. The gas sensor as claimed in claim 1, wherein the first insulating layer is any one of silicon oxide [SiO ₂ ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], and silicon nitride [SiN _x ], and the thickness of the first insulating layer is 10 nm to 1000 nm. The gas sensor of claim 1, wherein the dielectric layer is any one of silicon nitride [SiN _x ], aluminum oxide [Al ₂ O ₃ ], and aluminum nitride [AlN]. The gas sensor as claimed in claim 1, wherein the second insulating layer is any one of silicon oxide [SiO ₂ ], aluminum oxide [Al ₂ O ₃ ], aluminum nitride [AlN], and silicon nitride [SiN _x ], and the thickness of the second insulating layer is 10 nm to 300 nm. The gas sensor as described in claim 1, wherein the thickness of the sensing layer is 50nm~500nm.