Nano Structure Metal Oxide Ceramic Thin Film for Detection of Trace Moisture Using CMOS Timer

Abstract

A trace moisture analyzer is described below which consists of a moisture sensor with nano porous thin film sol-gel processed g-Al2O3 dielectric and active circuit. The thinner layer pore geometry enhancing the entrapment of water molecules makes it high wet to dry capacitance ratio. A simple dual-CMOS timer has been developed to detect moisture by controlling the monostable pulse width. Monostable pulse correlates the ambient moisture. The sensor is tested in combination with the circuit. Excellent quasi linearity is observed over the range from 0-50 ppmv. An experimental graph shows resolution better than 1% and accuracy of 2%. The response time is less than 2 minutes.

Keywords

• g-Al2O3
• Thin film
• Moisture sensor
• CMOS timer