Title :
An on-wafer fabricated free-chlorine sensor
Author :
van den Berg, A. ; Koudelka-Hep, M. ; van der Schoot, B.K. ; Verney-Norberg, E. ; Krebs, P. ; Grisel, A. ; de Rooij, N.F.
Author_Institution :
Inst. of Microtechnol., Neuchatel Univ., Switzerland
Abstract :
A method for on-wafer fabrication of free-chlorine sensors is described. The sensor structure consists of a planar three-electrode electrochemical cell covered with a polyHEMA hydrogel membrane. This membrane is photolithographically patterned on-wafer. In order to guarantee a good adhesion of the membrane to the electrode surface a special oxidation consisting of a treatment in an oxygen plasma has been developed followed by a silanization procedure. The optimal operational polarization voltage for detection of free chlorine was found to be +50 mV vs. SCE. Sensors with membrane thicknesses of 10 and 50 mu m were found to give approximately linear calibration curves between 0.1 and 5 mg/1 free chlorine, with sensitivities of 2 and 0.4 nA/(mg/1), respectively.<>
Keywords :
chlorine; electric sensing devices; electrochemical analysis; electrochemical electrodes; membranes; oxidation; photolithography; voltammetry (chemical analysis); Pt electrode; Si wafer; cyclic voltammetry; free Cl sensor; linear calibration curves; on-wafer fabrication; optimal operational polarization voltage; oxidation; photolithographically patterned; planar three-electrode electrochemical cell; polyHEMA hydrogel membrane; residual water disinfectant monitoring; silanization procedure; Adhesives; Biomembranes; Electrodes; Fabrication; Oxidation; Plasmas; Polarization; Sensor phenomena and characterization; Surface treatment; Voltage;
Conference_Titel :
Solid-State Sensors and Actuators, 1991. Digest of Technical Papers, TRANSDUCERS '91., 1991 International Conference on
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-87942-585-7
DOI :
10.1109/SENSOR.1991.148845
