CIP (cleaning-in-place) suitable “non-glass” pH sensor based on a Ta2O5-gate EIS structure

“Non-glass” pH-sensitive capacitive EIS (electrolyte–insulator–semiconductor) sensors consisting of a Ta2O5-gate have been investigated in terms of their CIP (cleaning-in-place) suitability. After optimisation of the process parameters, even after 30 CIP cycles, the sensors show a clear pH response and nearly linear calibration curve. The video-microscopic and scanning electron microscopy investigations do not show any visible degradation or destruction of the Ta2O5 films.