A new structured isfet with integrated Ti/Pd/Ag/AgCl electrode and micromachined back‐side P+ contacts

Autor:	Lieh-Hsi Lo, Ruey-Shing Huang, I-Yu Huang
Rok vydání:	2002
Předmět:	Materials science business.industry System of measurement Transistor General Engineering Nanotechnology Insulator (electricity) Reference electrode Electrical contacts law.invention Planar Quinhydrone electrode law Optoelectronics ISFET business
Zdroj:	Journal of the Chinese Institute of Engineers. 25:327-334
ISSN:	2158-7299 0253-3839
DOI:	10.1080/02533839.2002.9670707
Popis:	To eliminate the need for a separate reference electrode and facilitate the use of an ion‐sensitive field‐effect transistor (ISFET) in a measurement system, a planar Ti/Pd/Ag/AgCl quasi reference electrode integrated with ISFET in one chip has been developed. This new planar integrated quasi reference electrode, without filling any internal reference solution, has stable sensing characteristics and a satisfactory lifetime suitable for disposable sensing applications. Long‐term stability measurement over 60 hours shows an average drift of 0.035 mV/hr. SiO2/Ta2O5 was used for the sensing insulator, backside electrical contacts to the ISFET were adopted which make encapsulation easier. The fabricated pH sensors characterized in standard pH solutions show a linear sensitivity of 56 mV/pH. These results agree very well with the theoretical value of 59 mV/pH. Dynamic response and hysteresis characteristics of the pH‐sensor are also studied and discussed.
Databáze:	OpenAIRE
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