Optimization of a PVC Membrane for Reference Field Effect Transistors

Sensors

Chao-Sung Lai³  Cheng-En Lue³  Chia-Ming Yang²  Marek Dawgul¹ 

[1] Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences / ul. Trojdena 4, 02-109 Warsaw, Poland.;Device Section, Department of WAT and Devices, Inotera Memories Inc. / 667, Fuhsing 3^rd Road, Hwa-Ya Technology Park, Kwei-Shan, Tao-Yuan, Taiwan;Department of Electronic Engineering in Chang Gung University. / 259 Wen-Hwa 1^st Road, Kwei-Shan, Tao-Yuan, R.O.C., Taiwan, 333

关键词: PVC membranes;    ion-unblocking membranes;    REFET;    silylating;    plasticizers;   

DOI  :  10.3390/s90302076

来源: mdpi

【 摘 要 】

For the miniaturization of ISFET sensing systems, the concept of a REFET with low ion sensitivity is proposed to replace the conventional reference electrodes through the arrangement of a quasi reference electrode and a differential readout circuit. In this study, an ion-unblocking membrane was used as the top layer of a REFET. To optimize the REFET performance, the influences of the silylating process, different plasticizers, and the composition of the PVC cocktails were investigated. A low sensitivity (10.4 ± 2.2 mV/pH) and high linearity (99.7 ± 0.3 %) in the range from pH 2.2 to pH 11.6 was obtained for the REFET with a 60 wt.% DNP/(DNP + PVC) membrane. To evaluate the long term stability, the drift coefficient was estimated, and for the best REFET, it was −0.74 mV/h. Two criteria for assessing the lifetime of REFETs were used, namely the increase in pH sensitivity to a value higher than 15 mV/pH and the degradation of linearity below 99 %. For the best REFET, it was approximately 15 days.

【 授权许可】

CC BY   
© 2009 by the authors; licensee MDPI, Basel, Switzerland