Guard junction for semiconductor devices

Claim 2

A semiconductor device having a semiconductor body comprising a first zone of a first conductivity type adjoining a substantially flat surface of the semiconductor body, a second zone of a second conductivity type adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first and second zones a first p-n junction which terminates at said surface, at least one further zone of the second conductivity type situated beside the second zone, said further zone adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first and the further zones a second p-n junction which terminates at said surface, an insulating layer disposed on said surface and having a contact window and an aperture, a contact layer disposed on the insulating layer and connected throuGh said window to the second zone, and at least one conductive layer on the insulating layer which substantially surrounds the contact layer and is conductively connected to a surface part of the further zone through said aperture in the insulating layer, said further zone having an inner periphery and an outer periphery, said inner periphery being located closer to said contact layer than said outer periphery, said surface part being spaced from the outer periphery of the further zone, said conductive layer situated on the insulating layer extending to above the first zone substantially along the entire outer periphery of the further zone, said conductive layer being unconnected to an external circuit so that said conductive layer is at floating potential.

Claim 3

A semiconductor device having a semiconductor body comprising a first zone of a first conductivity type adjoining a substantially flat surface of the semiconductor body, a second zone of a second conductivity type adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first and second zones a first p-n junction which terminates at said surface, at least one further zone of the second conductivity type situated beside the second zone, said further zone adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first zone and the further zone a second p-n junction which terminates at said surface, an insulating layer disposed on said surface and having a contact window and an aperture, a contact layer disposed on the insulating layer and connected through said window to the second zone, and at least one conductive layer on the insulating layer which substantially surrounds the contact layer and is conductively connected to a surface part of the further zone through said aperture in the insulating layer, said further zone having an inner periphery and an outer periphery, said inner periphery being located closer to said contact layer than said outer periphery, said conductive layer situated on the insulating layer extending to above the first zone along substantially entirely both the inner and outer peripheries of the further zone, said conductive layer being unconnected to an external circuit so that said conductive layer is at floating potential.

Claim 4

A semiconductor device having a semiconductor body comprising a first zone of a first conductivity type adjoining a substantially flat surface of the semiconductor body, a second zone of a second conductivity type adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first and second zones a first p-n junction which terminates at said surface, at least one further zone of the second conductivity type situated beside the second zone, said further zone adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first zone and the further zone a second p-n junction which terminates at said surface, an insulating layer disposed on said surface and having a contact window and an aperture, a contact layer disposed on the insulating layer and connected through said window to the second zone, and at least one conductive layer on the insulating layer which substantially surrounds the contact layer and is conductively connected to a surface part of the further zone through said aperture in the insulating layer, said further zone having an inner periphery and an outer periphery, said inner periphery being located closer to said contact layer than said outer periphery, said conductive layer situated on the insulating layer extending to above the first zone along substantially entirely both the inner and outer peripheries of the further zone, said conductive layer being unconnected to an external circuit so that said conductive layer is at floating potential.

Claim 5

A semiconductor device having a semiconductor body comprising a first zone of a first conductivity type adjoining a substantially flat surface of the semiconductor body, a second zone of a second conductivity type adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first and second zones a first p-n junction which terminates at said surface, at least one further zone of the second conductivity type situated beside the second zone, said further zone adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first zone and the further zone a second p-n junction which terminates at said surface, an insulating layer disposed on said surface and having a contact window and an aperture, a contact layer disposed on the insulating layer and connected through said window to the second zone, and at least one conductive layer on the insulating layer which substantially surrounds the contact layer and is conductively connected to a surface part of the further zone through said aperture in the insulating layer, said further zone having an inner periphery and an outer periphery, said inner periphery being located closer to said contact layer than said outer periphery, said surface part being spaced from the outer periphery of the further zone, said conductive layer situated on the insulating layer extending to above the first zone substantially along the entire inner periphery of the further zone, said conductive layer being unconnected to an external circuit so that said conductive layer is at floating potential.

Claim 6

A semiconductor device having a semiconductor body comprising a first zone of a first conductivity type adjoining a substantially flat surface of the semiconductor body, a second zone of a second conductivity type adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first and second zones a first p-n junction which terminates at said surface, at least one further zone of the second conductivity type situated beside the second zone, said further zone adjoining said surface and being entirely surrounded by the first zone within the semiconductor body to form between the first zone and the further zone a second p-n junction which terminates at said surface, an insulating layer disposed on said surface and having a contact window and an aperture, a contact layer disposed on the insulating layer and connected through said window to the second zone, and at least one conductive layer on the insulating layer which substantially surrounds the contact layer and is conductively connected to a surface part of the further zone through said aperture in the insulating layer, said further zone having an inner periphery and an outer periphery, said inner periphery being located closer to said contact layer than said outer periphery, said surface part being spaced from the outer periphery of the further zone, said conductive layer situated on the insulating layer extending to above the first zone substantially along the entire inner periphery of the further zone, said conductive layer being unconnected to an external circuit so that said conductive layer is at floating potential.

Claim 7

A semicOnductor device as claimed in claim 3, wherein the distance measured along a line parallel to the surface from the contact layer to the conductive layer is smaller than a distance along the line from the contact layer to the further zone and smaller than a distance along the line from the contact layer to the aperture.

Claim 8

A semiconductor device as claimed in claim 3, wherein the surface part of the further zone substantially entirely surrounds the contact layer.

Claim 9

A semiconductor device as claimed in claim 3, wherein a second conductive layer is present on the insulating layer and substantially entirely surrounds the first conductive layer and is electrically connected through an aperture in the insulating layer to a surface part of the first zone in which, measured parallel to the surface, a distance along a line from the contact layer to the second conductive layer is smaller than a distance along the line to the surface part of the first zone.

Claim 10

A semiconductor device as claimed in claim 6, wherein the surface part of the first zone substantially entirely surrounds the further zone.

Claim 11

A semiconductor device as claimed in claim 6, wherein the second conductive layer is connected to a contact zone of the first conductive type adjoining the surface, said contact zone is provided in the first zone and has a lower resistivity than the first zone and substantially entirely surrounds the further zone.

Claim 12

A semiconductor device as claimed in claim 3, wherein the inner periphery of the conductive layer is more closely disposed to the contact layer than is the inner periphery of said further zone and a distance along a line parallel to the surface from the contact layer to the outer periphery of the conductive layer is greater than a distance along the line from the contact layer to the outer periphery of the further zone.

Claim 13

A semiconductor device as claimed in claim 3, wherein the contact layer extends to above the first zone.

Claim 14

A semiconductor device as claimed in claim 3, wherein s surface zone of the first conductivity type having a lower resistivity than the first zone is present beside at least one further zone on the side of the contact layer, said surface zone substantially entirely surrounding the contact layer, while, measured parallel to the surface, a distance along a line from the contact layer to the conductive layer connected to the further zone is smaller than a distance along the line from the contact layer to the surface zone.

Claim 15

A semiconductor device as claimed in claim 11, wherein the surface zone of the first conductivity type adjoins the further zone.

Claim 16

A semiconductor device as claimed in claim 3, wherein the second p-n junction is at least partly covered and is substantially shortcircuited at the surface by the conductive layer.

Claim 17

A semiconductor device as claimed in claim 3, wherein the first zone consists of p-type silicon.

Claim 18

A semiconductor device as claimed in claim 3, wherein the first zone is the collector zone of a transistor and the second zone is the base zone of the transistor.

Claim 19

A semiconductor device as claimed in claim 3, wherein means are present for applying such potentials to the first zone and the second zone so that the first p-n junction is biased in a reverse direction at least temporarily.