Capacitive humidity sensor of interdigital sandwich structure

Abstract

The invention discloses a capacitive humidity sensor of an interdigital sandwich structure. The capacitive humidity sensor comprises a silicon substrate and multiple capacitive humidity sensing units, wherein each capacitive humidity sensing unit comprises an insulating layer, an interdigital electrode, a passivation layer, a humidity-sensitive material layer and a floating top electrode which are sequentially arranged from bottom to top; the humidity-sensitive material layers of all the capacitive humidity sensing units are shared; the floating top electrode of all the capacitive humidity sensing units is shared; and the interdigital electrodes, each humidity-sensitive material layer and the corresponding floating top electrode form a group of series-parallel resistance and capacitance network. According to the capacitive humidity sensor disclosed by the invention, each floating top electrode is formed by virtue of a photolithography technique, a series of sandwich capacitor structures are formed in the whole sensor structure, and the sandwich capacitor structures are relatively high in capacitance value, high in sensitivity and simple in structure; and moreover, a current path of each floating top electrode is detached into multiple parallel branches, the resistance on each parallel branch is reduced along with the detachment, and the parasitic resistance is reduced.

Description

technical field [0001] The invention relates to a capacitive humidity sensor with an interdigitated sandwich structure, which belongs to micro-electromechanical technology. Background technique [0002] Humidity is an important environmental parameter, which is of great significance in meteorological research, industrial production and other fields. In order to obtain more accurate humidity information, it is necessary to improve the sensitivity, accuracy and response speed of the humidity sensor, which puts forward requirements for the structure of the humidity sensor. [0003] In order to increase the sensitive capacitance and improve the sensitivity, Vaisala (company name) uses a parallel plate sandwich capacitive sensor in the product. In 2006, Ching-Liang Dai (person's name) realized an interdigitated capacitive humidity sensor with a high electrode height by using methods such as sacrificial layer and RIE; in 2009, Ji-Hong Kim (person's name) et al. proposed a A sand...

AI Technical Summary

Problems solved by technology

However, due to the limitations of the structure itself, the existing humidity sensors still have problems such as small sensitive capacitance or large parasitic resistance, which need to be improved

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