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Porous anode alumina humidity sensor and its preparing process

A technology of humidity sensor and porous anode, which is applied in semiconductor/solid-state device manufacturing, electrical components, circuits, etc., can solve the problems of low sensitivity and poor linearity, and achieve the effects of simple equipment, stable process and easy quality management

Inactive Publication Date: 2008-01-16
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The document "Highly ordered nanoporous aluminum films: Effect of pore size and uniformity on sensing performance, J. Mater. Res., Vol. 17 (2002): 1162-1171" reports another porous anodized aluminum moisture sensor, which is based on The single through-hole anodized aluminum diaphragm with an average pore diameter of 13.6nm is used as a moisture-sensitive material. Gold is vacuum evaporated on the surface of the through-hole of the diaphragm to form a surface interdigital electrode. It can be measured in the relative humidity range of 20-90%, with high precision and repeatability. Good performance, simple manufacturing process, etc., but poor linearity, especially low sensitivity at low humidity

Method used

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  • Porous anode alumina humidity sensor and its preparing process
  • Porous anode alumina humidity sensor and its preparing process
  • Porous anode alumina humidity sensor and its preparing process

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Embodiment 1

[0024] After electropolishing an aluminum sheet with a purity of 99.99% and a length, width and height of 35mm×15mm×0.3mm at room temperature in a mixed solution of perchloric acid and absolute ethanol with a volume ratio of 1:4, at 0°C, Two-step anodization was carried out in 0.3mol / L oxalic acid, and the anodic oxidation voltage was 40V. After the first step of anodic oxidation for 12 hours, the aluminum oxide layer was completely dissolved with a mixed solution of 6% phosphoric acid and 1.5% chromic acid by mass percentage; after the second step of anodic oxidation for 24 hours, the aluminum matrix was removed with a saturated copper chloride solution, and the (Quality) Phosphoric acid removes the blocking barrier layer, corrodes and expands the pores, and obtains an anodic aluminum oxide membrane with double through holes with an average pore diameter of 85 nm and a thickness of 110 μm as shown in Figure 2.

[0025] Using high-purity gold with a purity of 99.99% as the tar...

Embodiment 2

[0029] After electropolishing an aluminum sheet with a purity of 99.99% and a length, width and height of 35mm×15mm×0.3mm in a mixed solution of perchloric acid and absolute ethanol (1:4) at room temperature, Two-step anodizing was carried out in oxalic acid, and the anodizing voltage was 40V. After the first step of anodizing for 12 hours, use a mixture of 6% phosphoric acid and 1.5% chromic acid to completely dissolve the aluminum oxide layer; after the second step of anodizing for 12 hours, use a saturated copper chloride solution to remove the aluminum matrix, and use 5% phosphoric acid to remove the barrier potential Anodized aluminum membrane with double through-holes with an average pore diameter of 45nm and a thickness of 60μm was obtained.

[0030] In background vacuum 1.5 x 10 -4 Pa, deposition vacuum 0.5Pa, argon flow rate 1sccm, sputtering power 12W, substrate temperature 25 ℃ conditions, with 99.99% high-purity gold as the target material, with the average apertu...

Embodiment 3

[0032] After electropolishing an aluminum sheet with a purity of 99.99% and a length, width and height of 35mm×15mm×0.3mm in a mixed solution of perchloric acid and absolute ethanol (1:4) at room temperature, it was heated at 0°C and 0.3mol / L Two-step anodizing was carried out in oxalic acid, and the anodizing voltage was 40V. After the first step of anodizing for 12 hours, use a mixture of 6% phosphoric acid and 1.5% chromic acid to completely dissolve the aluminum oxide layer; after the second step of anodizing for 18 hours, use a saturated copper chloride solution to remove the aluminum matrix, and use 5% phosphoric acid to remove the barrier potential Anodized aluminum membrane with double through-holes with an average pore diameter of 73nm and a thickness of 85μm was obtained.

[0033] 8 x 10 in background vacuum -6Pa, deposition vacuum 1.9Pa, argon gas flow rate 5sccm, sputtering power 20W, substrate temperature 500 ℃ conditions, with 99.99% high-purity aluminum as the ...

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Abstract

The invention discloses a porous anodic alumina humidity transducer and the preparation method thereof. The metal film electrode of the transducer is a porous metal film electrode. Porous anodic aluminum membrane is communicated with the porous metal film electrode by holes along the thickness direction of the membrane, with via-holes provided in upper and lower surfaces thereof. The preparation method that the combination technique of two-step anode oxidation and acid corrosion is adopted to prepare the anodic aluminum membrane with the two via-holes; then the metal electrode is deposited on the upper and the lower surfaces of the anodic aluminum membrane by using RF magnetron sputtering to form the humidity transducer with the intercommunication between the electrode holes and the anodic aluminum holes on the metal electrode replica-surfaces of the anodic aluminum membrane The transducer can measure in the whole scope of relative humidity, and is characterized in simple structure, small volume, rapid response, good repeatability, and stable performance, etc., therefore, particularly suitable for being used in the precision electronic instruments.

Description

technical field [0001] The invention relates to humidity sensor technology, in particular to a porous anodized aluminum oxide humidity sensor and a preparation method thereof. Background technique [0002] Humidity sensor is an important electronic component, which has a wide range of applications in storage, industrial production, process control, environmental monitoring, household appliances, meteorology, etc. There are many varieties of humidity sensors, which can be roughly divided into four categories in terms of the moisture-sensitive materials used: electrolyte type, polymer type, semiconductor ceramic type and porous metal oxide semiconductor type. The electrolyte type has narrow measurement range, poor repeatability, and short service life; the high molecular polymer type has good moisture-sensing performance and high sensitivity, but has poor stability, corrosion resistance and stain resistance in high temperature and high humidity environments; semiconductor cera...

Claims

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Application Information

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IPC IPC(8): G01N27/12H01L21/00
Inventor 凌志远罗光霞陈烁烁王金池李屹
Owner SOUTH CHINA UNIV OF TECH