Fabrication of a Stripe-Gate Type pH Sensor for Inhibition of Drift in pH Measurement for Long-Term Soil Monitoring

An ISFET-type pH sensor with stripe gate electrodes to inhibit the drift was fabricated for long-term pH measurement. The line and space patterns of stripe gate electrodes were fabricated under the pH sensing membrane in a channel area of the FET. The voltage was applied to the gate electrodes to suppress the diffusions of the anions from the object solution in the sensing membrane. We confirmed the inhibition of the drift using the gate electrodes.