Surface-sensitive condenser type gas transducer and manufacturing method thereof

Abstract

The invention relates to a surface sensitive capacitance gas sensor and its making method, which comprises in sequence a first electrode, a silicon wafer, a silicon oxide, a second electrode and a film of sensitive material. The silicon oxide in the sensor acts as electric medium, and forms a plate capacitor between the silicon wafer and the second electrode; the film of sensitive material is placed on the outer surface of a pole plate of the plate capacitor. By taking use of the characteristic that a nanometer or micrometer material has a small tip curve radius, the gas to be tested is polarized to increase or decrease the electric charge on the plate capacitor; and the type of the tested gas is judged through the surface sensitive capacitance gas sensor by the change reflected by the capacitance signals. The surface sensitive capacitance gas sensor operates under normal temperature and pressure, avoids any influence of accumulation of gas adsorbed by the sensitive material on the dielectric constant of the medium layer, improves the steadiness, selectivity, signal to noise ratio, accuracy and sensibility of the surface sensitive capacitance gas sensor.

Description

[0001] Field of the Invention The present invention relates to the field of gas detection, in particular to a surface-sensitive capacitive gas sensor based on the fringe field effect of one-dimensional nano or micro materials and its manufacturing method. Background technique [0002] There are many types of gas sensors, such as oxide semiconductor gas sensors, solid electrolyte gas sensors, electrochemical gas sensors, metal gate MOS gas sensors, surface acoustic wave gas sensors, infrared gas sensors, etc. With the rise of nanotechnology, the excellent performance of nanomaterials has led to the rapid development of the field of sensors. Nanoparticles often have a large specific surface area, and the specific surface area per gram of this solid can reach hundreds or even thousands of square meters, which makes them useful as highly active adsorbents and catalysts, using nanoparticles and nanofilms to modify traditional Gas sensors such as oxide semiconductors, solid-state el...

AI Technical Summary

Problems solved by technology

However, the field ionization gas sensor has a great disadvantage in structure. The sensor must ionize the gas to be measured, and the ionized gas reaches the counter electrode to form a current to obtain the detection signal. The ion will be complicated during the movement process. The reaction (such as transfer, recombination, etc.) causes the ion charge to be lost, so there is some randomness in the detection results

[0004] E.S.Snow et al. proposed a single-walled carbon nanotube sensor using the capacitance principle to detect gas in the 2005 "Science" article and US20060249402 patent. The author used the single-walled carbon nanotube layer as the dielectric layer of the flat capacitor, and made the electrode layer On the top of the single-walled carbon nanotube layer, a complex semiconductor manufacturing process is required, and the accumulation of adsorbed gas by the single-walled carbon nanotube will cause the change of the dielectric constant of the dielectric layer, which will affect the effect of the capacitance test.

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