Encapsulation of interdigitated electrodes by PTFE coatings via closed batch initiated chemical vapor deposition

Official URL: https://dx.doi.org/10.1016/j.vacuum.2021.110691

Encapsulation of sensor electrodes is critical for stability and optimum performance of the device. Encapsulation method to be employed should be compatible with the device architecture, provide conformal coatings and be cost effective. In this study, closed batch initiated chemical vapor deposition (CB-iCVD) method is used to deposit Polytetrafluoroethylene (PTFE) encapsulation layers on interdigitated electrodes (IDE). The CB-iCVD method enables deposition of conformal, ultra thin PTFE coatings on patterned surfaces with high precursor consumption efficiencies. The electron microscopy analysis confirms the conformality of the smooth coatings on the IDEs. The encapsulation performance of the coatings in the presence of standard pH solution is demonstrated by the frequency dependent electrochemical impedance spectroscopy (EIS) analysis, which confirms that the PTFE layer can successfully isolate the electrodes from the reactive environment.