US 5,317,172 AGranted

PNPN semiconductor device capable of supporting a high rate of current change with time

AssigneeTexas Instruments Incorporated

InventorStephen W. Byatt

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Abstract

A PNPN semiconductor device has an inner P-type region which includes at least one ridge which extends into its outer N-type region and terminates short of the outer boundary of the outer N-type region, the inner P-type region includes a formation which is substantially level with the outer boundary of the outer N-type region, and the device includes a terminal which contacts the outer N-type region and the formation of the inner P-type region. An alternative structure of the PNPN semiconductor device has an inner P-type region having at least one elongate sub-region, of higher conductivity than the remainder of the inner P-type region, lying along the junction between the inner P-type region and the outer N-type region, the formation which is substantially level with the outer boundary of the outer N-type region, and the terminal which contacts the formation and the outer N-type region.

Claims19

Dependent claims

A PNPN semiconductor device comprising an outer P-type region having an outer surface boundary for the PNPN semiconductor device, an inner N-type region, an inner P-type region and an outer N-type region having an outer surface boundary for the PNPN semiconductor device with a first junction between the outer N-type region and the inner P-type region, a second junction between the inner P-type region and the inner N-type region and a third junction between the inner N-type region and the outer P-type region;

said inner P-type region including an outer formation around the periphery of the inner P-type region surrounding the inner P-type region on all sides extending from the inner P-type region to be substantially level with the outer surface boundary of the outer N-type region and within said outer formation at least a portion of higher conductivity than the remainder of the inner P-type region extending from the remainder of the inner P-type region and terminating short of the outer surface boundary of the outer N-type region whereby said portion of the inner P-type region forms part of said first junction;
and a first terminal on the outer surface boundary of the outer N-type region contacting the formation of the inner P-type region and a second terminal on the outer surface boundary of the outer P-type region.

Dependencies are inferred from the claim text.