| 摘要 |
PURPOSE:To obtain a chemical sensitivity field effect transistor (ISFET) having excellent dielectric strength and stability, by a method wherein a hydrophobic organic macromolecular film not allowing a charge such as an ion to permeate and having excellent water resistance is formed in a destructed part of a protection film. CONSTITUTION:The whole surfaces of a source region 2 and a drain region 3 formed by phosphorus diffusion on a P-type silicon substrate 1 processed minutely by anisotropic etching are covered, except lead contact parts 2a and 3a, with a silicon oxide film 4 as an insulation film not allowing an ion to permeate and with a silicon nitride film 5 as a protection film. Then, a lead wire is connected to a source contact part of ISFET, and this ISFET is made to operate as a working electrode, with a platinum used as the opposite electrode, in an electrolytic polymerization solution (e.g. a solution prepared by dissolving a styrene monomer and tetraethylammonium tetrafluoroboron in a mixed solvent of acetonitrile and toluene). Thereby an electrolytically polymerized film 9 is formed in a destructed corner part of the insulation film 4, so as to improve the dielectric strength. |
