Abstract
AbstractThe ion sensitive field effect transistor (ISFET) is a microsensor consists of the theorem of electrochemistry and the characteristic of a field effect transistor. The principle of the MOSFET is be used for ISFET. The metalline gate of the MOSFET is substituted for reference electrode / electrolyte / insulator. Hence, ISFET is a device composed of a ion selective electrode and a MOSFET device.In this thesis the zinc oxide membrane has been prepared by sputter, Sputter method as a novel pH-sensitive layer under different plasma gas flow rate (Ar/O) and substrate temperatures. The ZnO membrane was directly deposited on the p-type silicon substrate by sputter to form the ZnO / Si EIS structure. The variations of flat band voltage were reported by C-V measurement to survey the sensitivity of membrane. The characteristics of membrane were measured and analysed by Electron spectroscopy for chemical analysis (ESCA), Energy dispersive spectrometer (EDS), n&k, X-ray diffraction and Atomic force microscopy (AFM), respectively.Experimental results show that the fabrication parameters and characteristics of ZnO membrane are determined at plasma gas oxygen percentage 35%, the substrate temperature 25℃ via the EIS structure. There exhibits the best pH response of about 56.61 mV/pH in the range of pH 1-11.