Production method of nitric oxide gas sensor element

A technology of gas sensors and nitrogen oxides, which is applied in the direction of instruments, scientific instruments, measuring devices, etc., to achieve the effect of less process conditions and easy control

Inactive Publication Date: 2013-03-27
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, at present, there are few reports on the preparation of gas sensors made of silicon-based porous

Method used

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  • Production method of nitric oxide gas sensor element
  • Production method of nitric oxide gas sensor element
  • Production method of nitric oxide gas sensor element

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0026] Example 1

[0027] 1) Wafer cleaning

[0028] Cut a 2-inch n-type single-sided polished single-crystal silicon wafer with a resistivity of 0.01Ω·cm, a thickness of 400±10μm and (100) crystal planes into a rectangular silicon substrate with a size of 2.2cm×0.8cm, and place them in sequence. Into acetone solvent, absolute ethanol and deionized water for ultrasonic cleaning for 20 minutes, then put it in a 5% hydrofluoric acid aqueous solution for 15 minutes, then rinse with deionized water, and finally put the silicon wafer Reserve in water and ethanol.

[0029] 2) Preparation of silicon-based porous silicon with ordered pores

[0030] The porous silicon layer was prepared on the polished surface of the silicon wafer by the double-slot electrochemical method. The corrosive liquid used is an aqueous solution of hydrofluoric acid with a mass fraction of 7%, and the applied corrosion current density is 125mA / cm 2 , The corrosion time is 20min. Prepared at room temperature and wit...

Example Embodiment

[0035] Example 2

[0036] This embodiment is similar to embodiment 1, except that: in step 2), the etching time of silicon-based porous silicon with ordered pores is 10 minutes, the average pore diameter is 82.07 nm, and the porosity is 48.78%. The obtained porous silicon The silicon gas sensor element is at room temperature to 1ppm NO 2 The gas sensitivity is 2.011.

Example Embodiment

[0037] Example 3

[0038] This embodiment is similar to embodiment 1, except that: in step 2), the etching time of silicon-based porous silicon with ordered pores is 15 minutes, and the measured average pore diameter is 112.25 nm, and the porosity is 68.75%. The silicon gas sensor element is at room temperature to 1ppm NO 2 The gas sensitivity is 2.395.

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Abstract

The invention discloses a production method of a nitric oxide gas sensor element, which comprises the steps of 1, cleaning an n type single-face polished monocrystalline silicon piece; 2, producing silicon substrate hole-order porous silicon with hole size of 50-200nm on the polished surface of the silicon piece by adopting a double-groove electrochemical corrosion method, wherein a corrosion solution is a hydrofluoric acid water solution with concentration of 6-8 percent, the density of the applied corrosion current is 115-135mA/cm<2>, and the corrosion time is 5-25min; and 3, placing the porous silicon in a vacuum chamber of an ultrahigh vacuum facing-target magnetron sputtering device, and producing the nitric oxide gas sensor element based on the silicon substrate hole-order porous silicon. The production method has the advantages of simpleness, flexibility, adjustability, less process conditions and easiness in control; and the nitric oxide gas sensor element has the advantages of high sensitivity, high selectivity, quick response/recovery characteristic and good repeatability under the conditions of room temperature and extreme low concentration (0.1ppm).

Description

technical field [0001] The invention relates to a gas sensor, in particular to a method for preparing a gas sensor element based on a silicon-based hole-ordered porous silicon nitrogen oxide gas sensor. Background technique [0002] With the rapid development of modern industry, it has also continuously brought serious pollution to the ecological environment, and has also caused great harm to human health. Nitrogen oxides (NO x ) as a toxic and harmful gas is the main cause of acid rain and photochemical smog. Extensively studied semiconducting metal oxide gas-sensing materials, although sensitive to NO x It has good sensitive performance, but it has the problem of high working temperature (much higher than room temperature), which adds complexity and instability to the development of miniaturized, integrated, and low-power sensor technology. At present, it is still a very challenging task to achieve room temperature detection of low-concentration nitrogen oxide gases. ...

Claims

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Application Information

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IPC IPC(8): G01N27/00
Inventor 胡明李明达刘青林马双云曾鹏
Owner TIANJIN UNIV
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