Ba_xSr_1−xTiO₃ sensing membrane in electrolyte-insulator-semiconductor structure with rapid thermal annealing in N₂ ambient

Ion-sensitive field - effect transistor (ISFET) biosensors were fabricated with a pH-sensitive Ba_xSr_1−xTiO₃ membrane on silicon substrates in an Electrolyte-Insulator-Semiconductor (EIS) structure. To investigate the effects of annealing in N₂ ambient, multiple material analyses including XRD and AFM were performed. Results indicate that the annealing treatment might deteriorate the crystallization. Therefore, the sensing behaviours in terms of sensitivity, linearity, hysteresis effects, and drift rates might be worsened. In this research, Ba_xSr_1−xTiO₃ membranes in an EIS structure with a high sensitivity and linearity were made. However, owing to its special and complicated structures, high-temperature thermal annealing was not suitable for the Ba_xSr_1−xTiO₃ membrane to further boost its sensing capability.