Fabrication of a low leakage current type impedance sensor to monitor soil water content for slope failure prognostics

A low-leakage-current type impedance sensor chip with shield structures has been fabricated. The low limit detection of soil-water-content measurement was improved compared with that of the other semiconductor type sensors. The shield structures were fabricated under the impedance sensor areas. To measure weak signal current eliminated the leakage current, we proposed a new operation circuit to separate the leakage current. Our sensor achieved to measure low water content 10 % or less.