Chemical response of Si/sub 3/N/sub 4//SiO/sub 2//Si structures used in pH microelectronic sensors

Review–Silicon Based ISFETs: Architecture, Fabrication Process, Sensing Membrane, and Spatial Variation

“…[107][108][109][110][111][112][113] A higher sensitivity device is always desirable for both in-vivo and in-vitro systems. Several factors influence the sensitivity of a pH ISFET, including biorecognition layer and the transducer, 7 sensing channel material, 8 resident of hydroxyl group, measuring process and time, 114 processing parameters such as gas flow ratio, 115 fabrication process, 8,[114][115][116][117][118][119] pH sensor and interface unit, 117 parasitic effects (transconductance), 118 total surface-site density (N S ), 34,120,121 presence of oxygen on the surface and hydrogen content in silicon nitride sensitive films, 122 annealing conditions, 115,123 dielectric constant, 123,124 biasing regime of sensors and electrostatic screening of the analyte charges, 125 leakage current, 126,127 drift, 101,[128][129][130] depletion width, 131 capacitance of floating diffusion (FD), 132 scale length with gate oxide thickness. 133 In addition to the aforementioned factors, there are several challenges commonly encountered during experiments.…”

“…Fabrication methods and materials.-Mansour Moinpour et al, 1989, 115 showed how the performance of ISFET sensors in biomedical applications is influenced by the fabrication process of gate dielectrics. This research investigated how pH sensitivity and voltage responsiveness of Si 3 N 4 /SiO 2 /Si structures were affected by processing factors such as gas flow ratio and annealing treatment.…”