MICROMACHINED ION-SELECTIVE ELECTRODES WITH POLYMER MATRIX MEMBRANES

We have developed a new method for the integration of ion-sensitive me mbranes and silicon sensor chips. The ion-sensitive membrane is deposi ted in pyramidal containments produced on silicon by an anisotropic et ching technique. Here we demonstrate the application of this method to the development of nitrate-sensitive sensors. PVC membranes are cast into the membrane containment. The sensors show an improved mechanical stability and lifetime compared to ISFETs. Slopes, detection limits a nd selectivities of the containment sensors are similar to those of io n-selective electrodes with internal electrolyte solution using the sa me membrane composition. The results of the drift and hysteresis measu rements are sufficiently good for most practical applications.