Field effect gas sensor taking air gap as insulation layer and preparation method thereof

Abstract

The invention discloses a field effect transistor gas sensor taking an air gap as an insulation layer and a preparation method. The preparation method mainly comprises the following steps of: spin-coating an organic insulation layer on an electric conducting substrate to serve as a device supporting layer, and etching a part of the device supporting layer to prepare an air gap groove; placing a micro-nano crystal above the air gap; and preparing source and drain electrodes of the device by utilizing a gold plate pasting electrode method or a photoetching technology, wherein the air gap between the micro-nano crystal and a grid electrode at the bottom of the groove is taken as a grid electrode insulation layer of the device. According to the field effect transistor gas sensor taking the air gap as the insulation layer and the preparation method, disclosed by the invention, the pollution and the damage to the surface of the nano-crystal due to the contact of the insulation layer in a preparation process is avoided; the point discharge effect is avoided favorably, and the stability of the sensor is increased; the success rate for preparing the device is greatly increased, and the device performance is improved; and an electric conducting channel is directly exposed in gas to be tested, and thus the field effect transistor gas sensor has a better air-sensitive performance. The field effect transistor gas sensor disclosed by the invention has the advantages of good stability, high sensitivity, detection limit reaching ppb (parts per billion) order and high response speed and recovery speed.

Description

technical field [0001] The invention belongs to the field of sensing technology, and in particular relates to a field-effect gas sensor with an air gap as an insulating layer and a preparation method thereof. [0002] Background technique [0003] From 1962, Seiyama, T.; Kato, A.; Fujiishi, K.; Nagatani, M. Anal. Chem. 1962, 34, 1502–1503) discovered that the active gas in the air at 400 °C can After changing the conductivity of ZnO thin films, gas sensors based on semiconductor materials have been widely studied. Due to the characteristics of high sensitivity, low cost, long life and convenient use of semiconductor gas sensors, after decades of development, there are countless various semiconductor sensors that can be used for gas detection. [0004] In recent years, gas sensors have increasingly higher requirements in terms of miniaturization, selectivity, stability, sensitivity, response time and service life, so the research and development of new gas sensors has also ...

AI Technical Summary

Problems solved by technology

More importantly, the solid insulating layer shields most of the conductive channel interface that is most sensitive to adsorbed molecules, which affects the further improvement of the sensitivity of the field effect gas sensor.

These problems limit the development of field-effect one-dimensional micro-nano single crystal gas sensors, and slow down the development of device miniaturization and nanometerization.

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