MICROTECHNOLOGIES FOR PH ISFET CHEMICAL SENSORS

A review of different microtechnologies for the fabrication of pH ion sensitive field effect transistor (ISFET) sensors is presented. Integr ated ISFETs are of interest due to the advantages of low price, fast r esponse and small dimensions that they present compared to ISE electro des. ISFETs can be also applied to the detection of different ions, us ing the proper sensitive membranes. A lot of work has been done during the last few decades to obtain commercial devices, and many technolog ies and structures can be found in the literature. In this paper, both front-side and back-side contacted devices are studied, in order to d etermine the compatibility of different processes, devices and materia ls with standard CMOS technologies, which seems to be a goal for prese nt and future applications. (C) 1997 Elsevier Science Ltd.