Solid state ion sensor with polyimide membrane
First Claim
1. An integrated circuit chemical sensor arrangement comprising:
- an input electrode formed of a conductive material in the vicinity of a region formed of a silicon-based semiconductor material; and
a permselective membrane having an ion-selective electrochemical property and formed by dissolving a polyimide-based compound in a solvent with a plasticizer selected from the group consisting of dimethy phthalate (DMP) and diethylene glycol dibenzoate LDGD), and a neutral carrier ionophore and then removing said solvent, whereby said plasticizer and said neutral carder ionophore are uniformly distributed in said polyimide-based compound, said permselective membrane being arranged to be in adherence with said silicon-based semiconductor material and in electrical communication with said input electrode, for producing at said input electrode a voltage responsive to said electrochemical property, whereby said permselective membrane is formed of solidified polyimide.
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Abstract
A polyimide matrix is employed to form a substance-sensitive membrane which is particularly suited for installation on a solid state sensor. Polyimide, dissolved in a solvent, such as N,N-dimethylformamide, or N-methyl-2-pyrrolidone (polyimide encapsulant), is combined with an ionophore, plasticizer, and a lipophilic additive. The ionophore may be a calcium ionophore, an ammonium ionophore, or any other ionophore. The membrane may also incorporate, or may be covered by, a bioactive agent, such as an enzyme, an immunochemical, bacteria, antibody, virus, or antigen. The plasticizer is one or both of dimethyl phthalate and diethylene glycol dibenzoate. The lipophilic additive may be potassium tetrakis(p-chlorophenyl)borate. The resulting substance-sensitive membrane has electrochemical properties which compare favorably to those of conventional PVC membranes, and exhibit significantly greater adhesion to glasses and semiconductor substrate materials. The improved adhesion may prolong the life of the sensors and prevent the formation of electrolyte shunts which have been known to render solid state sensors inoperative.
31 Citations
13 Claims
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1. An integrated circuit chemical sensor arrangement comprising:
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an input electrode formed of a conductive material in the vicinity of a region formed of a silicon-based semiconductor material; and a permselective membrane having an ion-selective electrochemical property and formed by dissolving a polyimide-based compound in a solvent with a plasticizer selected from the group consisting of dimethy phthalate (DMP) and diethylene glycol dibenzoate LDGD), and a neutral carrier ionophore and then removing said solvent, whereby said plasticizer and said neutral carder ionophore are uniformly distributed in said polyimide-based compound, said permselective membrane being arranged to be in adherence with said silicon-based semiconductor material and in electrical communication with said input electrode, for producing at said input electrode a voltage responsive to said electrochemical property, whereby said permselective membrane is formed of solidified polyimide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification