CN212540216U - High-selectivity array MOS sensor - Google Patents
High-selectivity array MOS sensor Download PDFInfo
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- CN212540216U CN212540216U CN202020694718.6U CN202020694718U CN212540216U CN 212540216 U CN212540216 U CN 212540216U CN 202020694718 U CN202020694718 U CN 202020694718U CN 212540216 U CN212540216 U CN 212540216U
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Abstract
A high selectivity array MOS sensor, comprising: a substrate; the plurality of sensitive units are formed on the substrate and form an array structure; the heater is formed on the substrate and is arranged at the periphery of the sensitive unit; the electrode layer is formed on the substrate and is electrically connected with the sensitive unit and the heater; the electrode layer comprises a plurality of leading-out terminals for monitoring the terminal potential of different sensitive unit combinations. The utility model discloses an adopt a plurality of leading out of a plurality of array structure's sensitive unit and electrode layer to hold in order to form the connecting circuit of different sensitive unit combinations, can realize the high sensitive response of different gases.
Description
Technical Field
The utility model relates to a semiconductor sensor technical field especially relates to a high selectivity array MOS sensor.
Background
With the development of industrial and urban traffic, a great amount of toxic and harmful gases released from industrial parks, industrial boilers, automobile exhaust, furniture and building materials cause the living environment to be full of a great amount of toxic and harmful gases (mainly CO and CO)2、SO2、NO2、H2S, formaldehyde and the like), how to realize effective treatment, and the key problem is to solve the high-precision, high-sensitivity and quick detection of the pollution source. Therefore, a large number of sensors with high sensitivity and high precision are urgently needed to realize field analysis or on-line monitoring.
The metal oxide detector is an important and widely-used detector, and the detector is very widely used due to low price and very wide gas detection range (a corresponding sensitive film can be selected according to gas components to realize detection of various gases).
However, the existing Metal Oxide Semiconductor (MOS) has poor specificity due to design concept and limitation of sensitive materials, and can respond to some other gas components in addition to high sensitivity to a designed gas, which is very easy to cause detection errors and even errors, thereby failing to effectively reflect the real condition of the gas in the environment.
SUMMERY OF THE UTILITY MODEL
In view of the above, the present invention provides a high selectivity array MOS sensor, which is intended to at least partially solve at least one of the above-mentioned technical problems.
In order to achieve the above purpose, the technical solution of the utility model is that:
an array MOS sensor, comprising:
a substrate;
the plurality of sensitive units are formed on the substrate and form an array structure;
the heater is formed on the substrate and is arranged at the periphery of the sensitive unit;
the electrode layer is formed on the substrate and is electrically connected with the sensitive unit and the heater;
the electrode layer comprises a plurality of leading-out terminals for monitoring the terminal potential of different sensitive unit combinations.
Based on above-mentioned technical scheme, the utility model discloses compare in prior art, have one of them or one of them part of following beneficial effect at least:
(1) the sensitive unit of the utility model adopts unique array structure design, the structure is provided with a plurality of sensitive units, the electrode layer comprises a plurality of leading-out ends, and the high-precision detection of various gases can be realized by the connection mode of different combinations of the sensitive units led out by the leading-out ends;
(2) at the bottom of the sensitive area, a silicon substrate is hollowed to leave a base of only 5-10 microns as a supporting beam, and the structure can reduce the heat loss of the base;
(3) the double-heater structural design is adopted, the structure enables the heat distribution of the sensitive area to be more balanced, and the high-selectivity array MOS sensor can be ensured to work at an ideal working temperature;
(4) the high-selectivity array MOS sensor is externally connected with an adjustable T4The power module at the end of the fourth leading-out terminal can intelligently select a corresponding sensitive unit from the multiple sensitive units to be in an ideal working state according to different components to be detected, so that high-sensitivity response to different gases is realized.
Drawings
Fig. 1 is a schematic structural diagram of a high selectivity array MOS sensor according to an embodiment of the present invention;
fig. 2 is a bridge circuit diagram of a high selectivity array MOS sensor according to an embodiment of the present invention;
FIG. 3 is a schematic cross-sectional view A-A of FIG. 1;
fig. 4 is a schematic diagram of a high selectivity array MOS sensor spraying operation according to an embodiment of the present invention;
fig. 5 is a schematic structural view of an electrode layer of an embodiment of the present invention being a parallel plate electrode;
fig. 6 is a schematic structural view of an embodiment of the present invention, in which the motor layer is an interdigital electrode.
In the above figures, the reference numerals have the following meanings:
1-an electrode layer; 2-a heater; 3-a sensitive unit; 4-a substrate; 41-a silicon substrate; a 42-silicon nitride layer; 5-photoresist mask; t is1-a first lead-out; t is2-a second lead-out; t is3-a third lead-out; t is4-a fourth terminal.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings.
As an aspect of the present invention, as shown in fig. 1, there is provided an array MOS sensor, including: a substrate 4, a plurality of sensing units 3, a heater 2 and an electrode layer 1; wherein a plurality of sensitive units 3 are formed on a substrate 4, and the plurality of sensitive units 3 form an array structure; the heater 2 is formed on the substrate 4, and the heater 2 is positioned at the periphery of the sensitive unit 3; and the electrode layer 1 is formed on the substrate 4, the electrode layer 1 is electrically connected with the sensitive units 3 and the heater 2, and the electrode layer 1 comprises a plurality of leading-out terminals for monitoring the terminal potential of different combinations of the sensitive units 3.
The working principle of the array MOS sensor is that gas is introduced and adsorbed on the sensitive unit 3, so that the resistance value of the resistor of the sensitive unit 3 is changed, the voltage value at two ends of the electric connection is correspondingly changed, and the potential of the output end of the electrode layer 1 is changed.
The utility model discloses an in the embodiment, one of them terminal of drawing forth of a plurality of terminals is used for ground connection, and another one draws forth the terminal and is used for connecting adjustable electric potential, and remaining other terminals of drawing forth are the potential detection end. The leading-out end of the array MOS sensor, which is connected with the adjustable potential, is externally connected with a power module capable of adjusting the voltage, and a corresponding sensitive unit 3 in the plurality of sensitive units 3 can be intelligently selected to be in an ideal working state according to different components to be detected.
In the preferred embodiment of the present invention, three rectangular sensing units 3 (S)1、S2、S3) Forming a rectangular array structure, as shown in fig. 1 and 2, the electrode layer 1 includes four terminals, which are respectively defined as first terminals T1A second lead-out terminal T2And a third terminal T3And a fourth terminal T4(ii) a First leading-out terminal T1And a fourth terminal T4Arranged diagonally and having a second lead-out terminal T2And a third terminal T3Arranged diagonally; wherein, the first leading-out terminal T1The grounding device is used for grounding; fourth terminal T4For connecting an adjustable potential; second terminal T2And a third terminal T3Respectively, a potential detecting end. In addition, the heater 2 comprises two heaters which are respectively and symmetrically formed at the periphery of the three sensitive units 3.
For example, as shown in FIG. 2, when U is monitoredTIT3、UT1T2、UT2T4The variation of each voltage value comprising a variation of the potential of at least one sensitive unit 3, e.g. UT1T2Is RS1And Rs2Sum of potential changes of UT2T4Is Rs3And measuring the potential changes of the end points, and obtaining the concentration of each component in the mixed gas through a neural network algorithm.
Here, the different terminal potentials include the resistance changes caused by different sensitive materials, and thus each terminal potential includes at least one gas-generated response. The utility model discloses a combine the voltage of these test ends, try out the accurate concentration of each gas component that is surveyed through neural network algorithm.
The neural network algorithm is a mature algorithm, the principle of the algorithm is equivalent to the simultaneous connection of several equations containing unknowns, and the quantity of each unknowns is obtained by solving. The function of finding the concentration of the measured gas component using the neural network algorithm can be implemented based on conventional hardware such as a single chip microcomputer and the like and conventional software programming, and therefore the present invention does not relate to improvements in procedures and algorithms.
The number of the sensing units 3 and the number of the leading-out terminals are not limited to the preferred embodiment, i.e. three sensing units 3 and four leading-out terminals, and the corresponding number and the corresponding circuit connection mode can be designed according to the actual requirements of the high-selectivity array MOS sensor, so as to meet the actual monitoring requirements for the measured gas components.
On one hand, the utility model improves the selectivity and sensitivity of gas detection by the array structure design of the sensitive units and the detection of different end potentials formed by the plurality of leading-out ends; on the other hand, the utility model discloses still through the sensitive material selection of sensitive unit 3, improve the selectivity of detecting.
In the embodiment of the present invention, the sensing unit 3 includes a sensing material compounded by graphene quantum dots, transition metal and metal oxide.
The utility model discloses a every sensitive unit 3 is decorated with the sensitive material of high specificity, according to the different choices of the sensitive material of every sensitive unit 3, like the samely, all different or part is the same (like two the same) among them, can realize the high accuracy detection to one or more gas component. For example, the plurality of sensitive units 3 comprise a sensitive material, response H, which is specifically responsive to formaldehyde2S sensitive material and response NH3One or more of the sensitive materials of (a).
In an embodiment of the present invention, the sensitive material is nano-sized particles; the transition metal comprises one or more of Co, Mn, Cu, Au and Ag; the metal oxide comprises SnO2、ZnO、In2O3、TiO2、WO3One or more of (a).
More specifically, the sensitive material of the embodiment of the present invention uses Graphene Quantum Dots (GQDs) as a basic material, and improves the hole concentration of the graphene quantum dots and promotes the charge electron transfer for different gas-selective doping transition metals such as Co, Mn, Cu, Au, and Ag; reselected SnO2、ZnO、In2O3、TiO2、WO3The metal oxide materials are compounded with the nano-sensitive material to form the nano-sensitive material.
In embodiments of the present invention, the sensitive material may be, but is not limited to, Au-graphene quantum dots/In2O3And Co-graphene quantum dots/SnO2And the like.
In the embodiment of the present invention, as shown in fig. 1, the heater adopts a dual-heater structure design, and is symmetrically formed on the periphery of the sensing unit 3; the structure ensures that the heat distribution of the sensitive region is more balanced, the sensitive unit 3 is heated uniformly, and the high-selectivity array MOS sensor can work at an ideal working temperature.
In the embodiment of the present invention, as shown in fig. 5, the electrode layer 1 is a parallel plate electrode structure, but is not limited thereto, and as shown in fig. 6, the electrode layer 1 may also be an interdigital electrode structure.
In the embodiment of the present invention, as shown in fig. 3 and 4, the base 4 includes, from bottom to top, a silicon substrate 41 and a silicon nitride layer 42;
the back of the silicon substrate 41 forms a back cavity, the back cavity corresponds to the sensitive area position of the sensitive unit 3, the base of the back cavity corresponding to the position forms a support beam,
as shown in FIG. 3, the thickness H of the support beam is 5-10 μm;
according to the high-selectivity array MOS sensor, the silicon substrate 41 is adopted to empty the base 4 with only 5-10 microns left as a supporting beam at the bottom of the sensitive area, and the structure can reduce the heat loss of the base 4.
The thickness of the silicon nitride layer 42 is 0.2-1 micron, and the silicon nitride layer 42 is designed to ensure that the support beam has a certain strength and is not easily affected by air flow.
As a preferred embodiment, the silicon nitride layer 42 is 1 micron thick.
As another aspect of the present invention, there is also provided a method for manufacturing the high selectivity array MOS sensor as described above, including the following steps:
photoetching the surface of the silicon nitride layer 42 to obtain a structural diagram of the heater 2, sputtering a layer of Pt/Cr with the thickness of 100-300 nm, preferably 120nm, and then stripping to obtain the heater 2.
Photoetching the surface of the silicon nitride layer 42 to obtain a structure diagram of the electrode layer 1, sputtering a layer of Au/Cr with the thickness of 100-300 nm, preferably 200nm, and then stripping to obtain the electrode layer 1.
It should be noted that the sequence of the steps of forming the heater 2 and the electrode layer 1 on the substrate 4 is not limited as long as the heater 2 and the electrode layer 1 are electrically connected.
As shown in fig. 4, a photoresist with a thickness of 2-3 μm is coated on the silicon nitride layer 42 to obtain a photoresist mask 5 exposing the sensitive region; wherein the sensitive area comprises a partial electrode layer area and a substrate area;
more specifically, the sensitive region is exposed, the photoresist in the non-sensitive region is retained, and a protective mask for the non-sensitive region is formed when the sensitive material is sprayed.
In the embodiment of the utility model, the sensitive material is sprayed on the sensitive area; as shown in fig. 4, the prepared sensitive material is uniformly sprayed on a predetermined sensitive area by using a spraying technique, and the thickness is determined according to the characteristics of the sensitive material.
Before spraying, the sensitive material forms a selective recognition structure for the gas to be detected by utilizing a molecular imprinting technology or a template molecular technology, so that an adsorption and analysis structure containing a characteristic shape of a certain gas is obtained, and high selectivity is realized.
In the embodiment of the present invention, the spot coating technique can be selected on the modification of the sensitive material, but in the preferred embodiment of the present invention, as shown in fig. 4, the photoresist mask 5 is adopted and the large-area spraying technique is combined, so that the good consistency effect of the sensitive unit 3 can be realized, and the thickness of the sensitive unit 3 can be accurately controlled according to the spraying rate and time.
And removing the photoresist mask 5 by adopting a reactive ion etching technology to expose the leading-out end of the electrode layer 1.
And aging in a nitrogen flow environment, namely aging the thermistor at high temperature to obtain the high-selectivity array MOS sensor.
In the embodiment of the present invention, the aging conditions include: the temperature is 400-600 ℃, and the time is 4-8 hours.
As a preferred embodiment, the aging temperature may be selected to be 350 ℃.
In the embodiment of the present invention, before the step of obtaining the photoresist mask 5 of the exposed sensitive region, the preparation method further includes the following steps: and removing part of the substrate 4 corresponding to the sensitive area by adopting an etching technology to form a back cavity.
In an embodiment of the present invention, before the step of forming the electrode layer 1 on the substrate 4, the preparation method further includes: the silicon substrate 41 is cleaned, and then a silicon nitride layer 42 is grown on the surface of the silicon substrate 41.
In conclusion, the high-precision uniform coating of the sensitive material is realized by adopting a precise mask and a large-area spraying method on the modification and fixation of the nano sensitive material, and the sensitive unit 3 prepared by the technology has good uniformity and the thickness of the sensitive unit 3 can be precisely controlled, which cannot be realized by the spot coating technology.
The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. An arrayed MOS sensor, comprising:
a substrate;
the plurality of sensitive units are formed on the substrate and form an array structure;
the heater is formed on the substrate and is arranged at the periphery of the sensitive unit;
the electrode layer is formed on the substrate and is electrically connected with the sensitive unit and the heater;
the electrode layer comprises a plurality of leading-out terminals for monitoring the terminal potential of different sensitive unit combinations.
2. The arrayed MOS sensor of claim 1, wherein one of the plurality of terminals is for ground, another terminal is for connection to an adjustable potential, and the remaining other terminals are potential sensing terminals.
3. The arrayed MOS sensor of claim 1 or 2, wherein the arrayed MOS sensor comprises:
the three rectangular sensitive units form a rectangular array structure;
the four leading-out ends are respectively positioned at the four end parts of the rectangular array structure and are respectively defined as a first leading-out end, a second leading-out end, a third leading-out end and a fourth leading-out end; the first leading-out end is used for grounding; the fourth leading-out terminal is used for connecting an adjustable potential; the second leading-out end and the third leading-out end are potential detection ends respectively;
and the two heaters are respectively and symmetrically formed at the periphery of the sensitive unit.
4. The arrayed MOS sensor of claim 1, wherein the electrode layer comprises a parallel plate electrode structure or an interdigitated electrode structure;
the material of the electrode layer comprises Au/Cr, and the thickness of the electrode layer comprises 100-300 nm.
5. The arrayed MOS sensor of claim 4, wherein the electrode layer has a thickness of 200 nm.
6. The arrayed MOS sensor of claim 1,
the sensitive materials of the plurality of sensitive units are the same, different or partially the same;
the sensitive material is nano-sized particles.
7. The arrayed MOS sensor of claim 1, wherein the heater material comprises Pt/Cr and the heater thickness comprises 100 to 300 nm.
8. The arrayed MOS sensor of claim 7, wherein the heater has a thickness of 120 nm.
9. The arrayed MOS sensor of claim 1, wherein the base comprises, from bottom to top, a silicon substrate and a silicon nitride layer;
and a back cavity is formed on the back of the silicon substrate, the back cavity corresponds to the position of the sensitive area of the sensitive unit, and a base at the position corresponding to the back cavity forms a support beam.
10. The arrayed MOS sensor of claim 9, wherein the support beam comprises a thickness of 5 to 10 microns;
the thickness of the silicon nitride layer comprises 0.2-1 micron.
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| CN202020694718.6U CN212540216U (en) | 2020-04-29 | 2020-04-29 | High-selectivity array MOS sensor |
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| CN202020694718.6U CN212540216U (en) | 2020-04-29 | 2020-04-29 | High-selectivity array MOS sensor |
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| CN212540216U true CN212540216U (en) | 2021-02-12 |
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Effective date of registration: 20220518 Address after: 100190 No. 19 West North Fourth Ring Road, Haidian District, Beijing Patentee after: Research Institute of aerospace information innovation, Chinese Academy of Sciences Patentee after: Shandong Lunan Ruihong Chemical Instrument Co., Ltd Address before: 100190 No. 19 West North Fourth Ring Road, Haidian District, Beijing Patentee before: Research Institute of aerospace information innovation, Chinese Academy of Sciences |