Method of making a voltage actuatable switch

Claim 1

The method of making a voltage actuated switch on a selected portion of the area of a substrate of conductive material that comprises: selecting a substrate of conductive material which has a smooth upper surface, forming an insulating layer which overlies and engages all of said selected portion of said substrate, forming said insulating layer so it has a predetermined constant thickness and predetermined resistivity to enable said insulating layer to have a predetermined breakdown voltage and also to have a substantially flat upper surface, removing a predetermined area of said insulating layer to expose all of said selected portion of said substrate of conductive materIal and to form a hole which has the sides thereof defined solely by said insulating layer, forming a further layer of insulating material that is located wholly within said hole, that directly engages said selected portion of said substrate, that overlies the entire bottom of said hole and that extends to and directly engages those portions of said insulating layer which define the sides of said hole, forming said further layer of insulating material so it has an essentially uniform thickness and a substantially flat upper surface, forming said further layer of insulating material so it has a portion of predetermined thickness and predetermined resistivity to enable said portion of said further layer of insulating material to have a second and different predetermined breakdown voltage, forming an electrode that overlies and engages one of said layers of insulating material, forming said one of said layers of insulating material so it has a thickness which is less than the thickness of the other layer of insulating material, whereby said one layer of insulating material has a breakdown voltage which is substantially lower than the breakdown voltage of said other layer of insulating material, forming said one layer of insulating material so it responds to the application of a voltage across said substrate and said electrode, which is greater than said breakdown voltage of said one layer of insulating material but which is less than the breakdown voltage of said other layer of insulating material, to break down and thereby permit an irreversible, low resistance connection to form between said electrode and said substrate, said substrate being formed from silicon, forming said layer of insulating material from silicon dioxide, and forming said further layer of insulating material from silicon dioxide.

Claim 6

The method of making a voltage actuated switch on a selected portion of the area of a substrate of conductive material that comprises: selecting a substrate of conductive material which has a smooth upper surface, forming an insulating layer which overlies and engages all of said selected portion of said substrate, forming said insulating layer so it has a predetermined constant thickness and predetermined resistivity to enable said insulating layer to have a predetermined breakdown voltage and also to have a substantially flat upper surface, removing a predetermined area of said insulating layer to expose all of said selected portion of said substrate of conductive material and to form a hole which has the sides thereof defined solely by said insulating layer, forming a further layer of insulating material that is located wholly within said hole, that directly engages said selected portion of said substrate, that overlies the entire bottom of said hole, and that extends to and directly engages those portions of said insulating layer which define the sides of said hole, forming said further layer of insulating material so it has an essentially uniform thickness and a substantially flat upper surface, forming said further layer of insulating material so it has a portion of predetermined thickness and predetermined resistivity to enable said portion of said further layer of insulating material to have a second and different predetermined breakdown voltage, forming an electrode that overlies and engages one of said layers of insulating material, forming said one of said layers of insulating material so it has a thickness which is less than the thickness of the other layer of insulating material, whereby said one layer of insulating material has a breakdown voltage which is substantially lower than the breakdown voltage of said other layer of insulating material, forming said one layer of insulating material so it responds to the application of a voltage across said substrate and said electrode, which is greater than said breakdown voltage of said one layer of insulating material but which is less than the breakdown voltage of said other layer of insulating material, to break down and thereby permit an irreversible, low resistance connection to form between said electrode and said substrate, forming said one layer of insulating material so it has a thickness which is substantially smaller than the thickness of said other layer of insulating material, dimensioning said one layer of insulating material so the major portion thereof will be converted from an initial high-resistance state to a low-resistance state as said one layer of insulating material responds to said voltage across said substrate and said electrode to break down.