Characteristics of silicon nitride after O-2 plasma surface treatment for pH-ISFET applications

Silicon nitride (Si3N4) sensing gate pa-ion-selective field effect transist ors (ISFETs) were treated by 2,54-GHz microwave O-2 plasma, the results sho w the ISFET sensitivity has an advantage up to 24% increment after the plas ma treatment. Electron spectroscopy for chemical analysis (ESCA) is used to make sure that the plasma treatment is not just a native oxide cleaning pr ocedure, The samples, which were immobilized with glutaraldehyde used as a bifunctional reagent and 3-aminopropyltriethoxysilane used as an adhesion p romoter were studied. The binding force between the glucose oxidase and glu taraldehyde immobilized samples, and the element concentrations of nitrogen in 3-aminopropyltriethoxysilane immobilized samples are higher which were treated by plasma.