Separate structure extended gate H+-ion sensitive field effect transistor on a glass substrate

The dual role of Parylene C in chemical sensing: Acting as an encapsulant and as a sensing membrane for pH monitoring applications

“…This has been also proven by our recent work which demonstrated that thinner passivations result in an increase of the electrostatic coupling of H + and, therefore, in an improved sensitivity of the ISFET sensors [9]. This functional property has also been exploited for a different reason; to improve the sensors' performance, reliability and lifetime by having the active transducer in a remote location from the chemical sensing site, also known as the extended-gate approach [10,11]. A further deployment of this concept was recently demonstrated by our group, in which discrete Metal-Oxide-Semiconductor FETs (MOSFETs) were employed as the active transducers [12].…”

Low temperature annealed amorphous indium gallium zinc oxide (a-IGZO) as a pH sensitive layer for applications in field effect based sensors

“…11 Therefore, the electrical conductivities of the sensing materials as well as of those of the base substrates greatly affect the sensing characteristics of EGFETs. A conducting sensitive material on an appropriate conducting substrate seems to be a basic need for fabrication of an extended gate electrode.…”

CMOS, Delta-Sigma pH-to-Digital Converter as New Integrated Device for Potentiometric Biosensors Applications

“…3 The operation of the extended-gate field effect transistor is very similar to that of a conventional MOS, except that an additional sensing structure is dipped in the buffer solution. In the study of pH sensitivity of the SnO 2 /ITO glass, the SnO 2 /ITO glass sensing membrane was connected to an instrumentation amplifier (Yin et al, 2000). The instrumentation amplifier was used to measure output response of the SnO 2 /ITO glass in the pH buffer solutions, and the result shows that the sensing membrane, SnO 2 /ITO glass, has a linear pH sensitivity of approximately 59.3mV/pH in the ion concentration ranging between pH 2 and 10.…”