Obliquely Deposited Electrode and Response Properties of Condenser-type Humidity Sensors

Abstract

High water vapor permeable metal electrode of condenser type humidity sensors is formed by using oblique deposition method to improve response.
Response time of the sensors with the electrode deposited at an incident angle θ= 75° is about 0.2 s even in the thickness of 1800Å or more. The process how to build up the electrodes in form and their density are also investigated. It is estimated that quick response comes from the formation of a columnar microstructure with porosity due to shadowing effect in this deposition technique.