US4735702A — Method of producing an ISFET and same ISFET

Claim 1

Independent Claim 61 words

In the process for significantly increasing the useful life of a field effect transistor by on the order of at least one month, which comprises the steps of modifying an oxide surface of said field effect transistor wherein a coating of a polymer is applied to the oxide layer, characterized in that the polymer is chemically bonded to said oxide surface.

Claim 2

Dependent Claim 61 words

In the process for significantly increasing the useful life of a field effect transistor by on the order of at least one month, which comprises the steps of modifying an oxide surface of said field effect transistor wherein a coating of a polymer is applied to the oxide layer, characterized in that the polymer is chemically bonded to said oxide surface.

Claim 3

Dependent Claim 28 words

Process as claimed in claim 1, characterized in that the polymer is formed out of at least one type of monomers which are polymerized to the oxide surface.

Claim 4

Dependent Claim 57 words

Process as claimed in claim 1, characterized in that an alkoxy- and/or halogen vinyl silane, epoxysilane, aminosilane, isocyanate silane is reacted with the oxide surface, and that the silane groups present on the surface are subsequently polymerized with at least one type of monomers having a vinyl group or more than one alcohol, amine and/or isocyanate group.

Claim 5

Dependent Claim 23 words

Process as claimed in claim 1, characterized in that the polymer is a "living" polymer which is chemically bonded to the oxide surface.

Claim 6

Dependent Claim 39 words

Process as claimed in claim 4, characterized in that on alkoxy- and/or halogen vinyl silane is reacted with the oxide surface and that the silane vinyl groups present on the surface are subsequently bonded chemically to the "living" polymer.

Claim 7

Dependent Claim 16 words

Process as claimed in claim 1, characterized in that the polymer is polyurethane, polyamide and/or polycarbonate.

Claim 8

Dependent Claim 32 words

Process as claimed in any of the claims 2-6, characterized in that the polymer is formed with the inclusion of a second type of monomers which comprise a metal ion complexing group.

Claim 9

Dependent Claim 26 words

Process as claimed in any of the claims 2-6, characterized in that a compound comprising a metal ion complexing group is chemically bonded to the polymer.

Claim 10

Dependent Claim 23 words

Process as claimed in claim 7, characterized in that the metal ion complexing group is a crown ether, cryptand, podand, spherand and/or ionophor.

Claim 11

Dependent Claim 14 words

Process as claimed in claim 9, characterized in that the crown ether is 4'-alkyl-benzo-18-crown-6.

Claim 12

Dependent Claim 35 words

Process as claimed in claim 1, characterized in that a second coating of a polymer comprising a metal ion complexing group is applied to the coating of the vinyl chemically bonded to the oxide surface.

Claim 13

Dependent Claim 19 words

Process as claimed in claim 11, characterized in that the second coating is physically adhered to the first coating.

Claim 14

Dependent Claim 39 words

Process as claimed in claim 12, characterized in that the second coating, in the form of one or more layers, is adhered to the first coating by spinning of a solution of the polymer comprising metal ion complexing groups.

Claim 15

Dependent Claim 19 words

Process as claimed in claim 11, characterized in that the second coating is chemically bonded to the first coating.

Claim 16

Dependent Claim 52 words

Process as claimed in claim 14, characterized in that the second coating, in one or more layers is applied to the first coating, by spinning of a solution of vinyl monomers comprising metal ion complexing groups, and in using an initiator is bonded to remaining vinyl groups present in the first coating.

Claim 17

Dependent Claim 23 words

Process as claimed in claim 11, characterized in that the metal ion complexing group is a crown ether, cryptand, podand, spherand and/or ionophor.

Claim 18

Dependent Claim 15 words

Process as claimed in claim 16, characterized in that the crown ether group is 4'-alkyl-benzo-18-crown-6.

Claim 19

Dependent Claim 77 words

Process for manufacturing an ISFET, comprising a semi-conductor material having an oxide surface, whereby a curable resin is applied over the semi-conductor material, and through the resin up to the oxide surface at least one gate is left, characterized in that prior to the application of the resin, the oxide surface is modified with a polymer as claimed in any of the claims 1-6, and that optionally at the location of the gate, the polymer is removed.

Claim 20

Dependent Claim 30 words

ISFET provided with a semi-conductor material having an oxide surface, characterized by at least one polymer chemically bonded on the oxide surface, as claimed in any of the claims 1-6.

Claim 21

Dependent Claim 72 words

In the method of making a field effect transistor having an insulated gate region, the steps of providing a semiconductor body having p- and n-regions defining a surface including the insulated gate region, and significantly increasing the useful life of the transistor, while it is in contact with an environment having polarity of one kind, by chemically bonding a first polymer having polarity opposite that of said one kind to said surface.

Claim 22

Dependent Claim 72 words

In the method of making a field effect transistor having an insulated gate region, the steps of providing a semiconductor body having p- and n-regions defining a surface including the insulated gate region, and significantly increasing the useful life of the transistor, while it is in contact with an environment having polarity of one kind, by chemically bonding a first polymer having polarity opposite that of said one kind to said surface.

Claim 23

Dependent Claim 30 words

In the method as defined in claim 20 wherein the useful life of the transistor while it is in contact with the environment is at least a number of months.

Claim 24

Dependent Claim 103 words

In the method of significantly increasing the useful life of a field effect transistor, having a sensitive gate region, when such field effect transistor is in contact with a polar liquid being monitored for the presence of an entity in the liquid to which the gate region is sensitive, which comprises the steps of providing a semiconductor body having an oxide layer of polar character on a surface thereof which encompasses and defines the sensitive gate region of the field effect transistor, and chemically bonding a layer of a first polymer having an apolar character on the oxide layer of the semiconductor body.

Claim 25

Dependent Claim 103 words

In the method of significantly increasing the useful life of a field effect transistor, having a sensitive gate region, when such field effect transistor is in contact with a polar liquid being monitored for the presence of an entity in the liquid to which the gate region is sensitive, which comprises the steps of providing a semiconductor body having an oxide layer of polar character on a surface thereof which encompasses and defines the sensitive gate region of the field effect transistor, and chemically bonding a layer of a first polymer having an apolar character on the oxide layer of the semiconductor body.

Claim 26

Dependent Claim 48 words

In the method as defined in claim 22 including the step of coating the first polymer layer with a layer of a second polymer having an apolar character and exposing a selected area of the first polymer layer overlying the sensitive gate region through the second polymer layer.

Claim 27

Dependent Claim 27 words

In the method as defined in claim 23 including the step of removing the selected area of the first polymer layer to expose the oxide layer therebeneath.

Claim 28

Dependent Claim 71 words

In the method as defined in claim 24 including the step of coating the selected area of the exposed first polymer layer with a further layer of a polymer having a sensitivity to a selected metallic ion, the thicknesses of the layer of the first polymer and the further layer of polymer having sensitivity to the selected metallic ion being sufficient to render the gate region substantially insensitive to hydrogen ions.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-04-05	1991-10-05	1992-04-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-04-05	1995-10-05	1996-04-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-04-05	1999-10-05	2000-04-05	$7700.00	Window Closed / Lapsed

Method of producing an ISFET and same ISFET

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