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

Abstract “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.

[1]  Hirokazu Hara,et al.  Dynamic response of a Ta2O5-gate pH-sensitive field-effect transistor , 1996 .

[2]  Hans Lueth,et al.  Semiconductor-based field-effect structures for chemical sensing , 2001, SPIE Optics East.

[3]  Jens Zosel,et al.  Encapsulation of ISFET sensor chips , 2005 .

[4]  J. W. Schultze,et al.  Multi-parameter detection of (bio-)chemical and physical quantities using an identical transducer principle , 2003 .

[5]  G. Oehrlein.  Oxidation temperature dependence of the dc electrical conduction characteristics and dielectric strength of thin Ta2O5 films on silicon , 1986 .

[6]  Hendrik Emons,et al.  Application of ISFETs for pH measurement in rain droplets , 2001 .

[7]  Michael J. Schöning,et al.  Detecting Both Physical and (Bio‐)Chemical Parameters by Means of ISFET Devices , 2004 .

[8]  J. Autran,et al.  Tantalum pentoxide (Ta2O5) thin films for advanced dielectric applications , 1998 .

[9]  P. Bergveld,et al.  Operation of chemically sensitive field-effect sensors as a function of the insulator-electrolyte interface , 1983, IEEE Transactions on Electron Devices.

[10]  S. Bouwstra,et al.  Tantalum oxide thin films as protective coatings for sensors , 1999, Technical Digest. IEEE International MEMS 99 Conference. Twelfth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.99CH36291).

[11]  Piet Bergveld,et al.  Thirty years of ISFETOLOGY ☆: What happened in the past 30 years and what may happen in the next 30 years , 2003 .

[12]  Elena Atanassova,et al.  Electrical properties of thin Ta2O5 films obtained by thermal oxidation of Ta on Si , 1997 .

[13]  Michael J. Schöning,et al.  Penicillin detection by means of field-effect based sensors: EnFET, capacitive EIS sensor or LAPS? , 2001 .

[14]  Byung-Ki Sohn,et al.  Effects of heat treatment on Ta2O5 sensing membrane for low drift and high sensitivity pH-ISFET , 1996 .

[15]  Sung Wook Park,et al.  Effects of oxidation conditions on the properties of tantalum oxide films on silicon substrates , 1992 .