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Capacity humidometer

A humidity measurement and capacitive technology, which is applied in the direction of material capacitance, etc., can solve problems such as poor performance, difficulty in accurate measurement, and difficulty in integration, and achieve the effects of simple method and structure, reduced total cost, and high precision

Inactive Publication Date: 2004-09-01
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Electrolyte humidity sensors have disadvantages such as narrow measurement range, poor repeatability, and short service life
The polymer compound humidity sensor has the advantages of good humidity sensing performance and high sensitivity, but has disadvantages such as poor performance, poor stability, poor corrosion resistance and stain resistance under high temperature and high humidity conditions.
Semiconductor ceramic material humidity sensors have the advantages of good humidity sensing performance, simple production, low cost, short response time, and heating and cleaning, but there are also disadvantages such as difficulty in accurate measurement, poor performance at high temperatures, and difficulty in integration.

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Embodiment 1: Manufacture 1 of a CMOS-compatible humidity sensor integrated chip.

[0017] Firstly, the sensitive capacitance structure and layout are designed. In order to be compatible with the standard CMOS integrated circuit production process, the heating resistor is realized by P well, the bottom electrode is made of high phosphorus doped silicon layer, and the top electrode is made of heavily doped polycrystalline. The polycrystal is formed together with the gate of the MOS transistor. The dielectric in the middle of the capacitor is a field oxide layer. The whole system is realized by standard P-well CMOS process. After completing the flow of the circuit chip, the entire chip is covered with silicon nitride and glue and opened by photolithography. figure 2 hole on top. Then use the buffered hydrofluoric acid solution commonly used in standard integrated circuit technology to remove the oxide layer under the small hole. In this way, the whole chip is prepare...

Embodiment 2

[0018] Embodiment 2: Manufacture 2 of a CMOS-compatible humidity sensor integrated chip.

[0019] The manufacturing method of the chip is exactly the same as above, and it is a standard CMOS process. The difference is that the composition of the sensitive capacitor structure shown is different from the first one. In this structure, the heating resistor adopts a heavily doped silicon layer. The bottom electrode adopts heavily doped polycrystalline. The poly is formed together with the gate of the MOS transistor. The dielectric in the middle of the capacitor is an oxide layer deposited at low temperature. The upper electrode is made of metal. The whole system can still be realized by P-well CMOS technology. A gold layer is used for the metal leads. After the circuit chip flow is completed, the entire chip is covered with silicon nitride and glue, and the small holes on it are opened by photolithography. Then use the buffered hydrofluoric acid solution commonly used in sta...

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PUM

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Abstract

The capacitive humidometer is one CMOS process compatible measuring device, and the device has an input capacitor connected to driving signal source, one sensitive capacitor connected to the input capacitor, one gating amplifier comprising MOS transistors and one outupt capacitor with one end connected to ground, integrated in one chip. The humidity-sensitive capacitor consists of upper conducting plate with many small holes, lower conducting plate, support material between two conducting plates, a heating resistor below the lower conducting plate and isolating layer between the heating resistor and the lower conducting plate. The humidity-sensitive capacitor and the amplifier and integrated to one identical chip via CMOS process.

Description

Technical field: [0001] The invention relates to a humidity detector used in measuring instruments, in particular to a measuring device composed of capacitive humidity sensors compatible with COMS technology. Background technique: [0002] Humidity sensors are manufactured based on the fact that their functional materials can undergo physical effects or chemical reactions related to humidity. It has the function of converting the physical quantity of humidity into an electrical signal. These functions can be achieved through temperature-related changes in resistance or capacitance, expansion and contraction in length or volume, and changes in certain electrical parameters of junction devices or MOS devices. It has a wide range of applications in military, weather, agriculture, industry (especially textile, electronics, food industry), medical, construction and household appliances. [0003] At present, there are many kinds of humidity sensors, but a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N27/22
Inventor 秦明黄庆安张中平
Owner SOUTHEAST UNIV