High sensing performance of fluorinated HfO2 membrane by low damage CF4 plasma treatment for K+ detections

A low damage CF₄ plasma with a filter in a PECVD system was proposed to incorporate fluorine atoms into an HfO₂ sensing membrane in an EIS structure for K⁺ ion sensor application. The highest sensitivities of 82mV/pK was obtained when the low damage plasma treatment with RF power of 100W was used for 30min. Compared with the conventional CF₄ plasma, the sensitivity significantly improved. The reasons were the high polarization induced by fluorine atoms and elimination of plasma damage.