Semiconductor device having electrostatic breakdown protection circuit
First Claim
1. A semiconductor device comprising an external metal terminal formed on a semiconductor substrate of a first conductivity type, an internal circuit formed in said semiconductor substrate and connected to said external metal terminal, and a bipolar transistor having a collector region and an emitter region formed in said semiconductor substrate which are separated from each other by a device isolation insulator film formed on said semiconductor substrate, each of said collector region and said emitter region being formed of a second conductivity type opposite to said first conductivity type, and a base of said bipolar transistor being formed of a portion of said semiconductor substrate between said collector region and said emitter region, one of said collector region and said emitter region being connected to said external metal terminal, another one of said collector region and said emitter region being connected to a predetermined common potential, so that when an electrostatic voltage is applied to said external metal terminal, said bipolar transistor is turned on so as to protect said internal circuit, wherein the improvement comprises a plurality of divided transistors connected in parallel which constitute said bipolar transistor as a whole, each of said divided transistors having a predetermined limited width less than the width of said bipolar transistor so as to increase the operating speed of said bipolar transistor, said divided protection transistors having a substantially equal breakdown voltage of a junction between a collector region and said semiconductor substrate.
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Accused Products
Abstract
A semiconductor device includes a metallic main line connected between an external terminal and an internal circuit, and a plurality of divided protection bipolar transistors connected in parallel to one another. Each of the divided protection bipolar transistors includes a collector and an emitter composed of first and second N diffused regions formed in a semiconductor substrate which are separated from each other. Each of the divided protection bipolar transistors also includes a base formed of a portion of a semiconductor substrate between the collector and the emitter. The collector is connected to a metallic sub line branched from the main line, and the emitter is connected to ground. The plurality of divided protection bipolar transistors have an equal breakdown voltage between the collector of the divided protection bipolar transistor and the semiconductor substrate. Thus, the protection device composed of a plurality of divided protection bipolar transistors connected in parallel to one another can effectively protect the internal circuit from a short electrostatic pulse.
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Citations
6 Claims
- 1. A semiconductor device comprising an external metal terminal formed on a semiconductor substrate of a first conductivity type, an internal circuit formed in said semiconductor substrate and connected to said external metal terminal, and a bipolar transistor having a collector region and an emitter region formed in said semiconductor substrate which are separated from each other by a device isolation insulator film formed on said semiconductor substrate, each of said collector region and said emitter region being formed of a second conductivity type opposite to said first conductivity type, and a base of said bipolar transistor being formed of a portion of said semiconductor substrate between said collector region and said emitter region, one of said collector region and said emitter region being connected to said external metal terminal, another one of said collector region and said emitter region being connected to a predetermined common potential, so that when an electrostatic voltage is applied to said external metal terminal, said bipolar transistor is turned on so as to protect said internal circuit, wherein the improvement comprises a plurality of divided transistors connected in parallel which constitute said bipolar transistor as a whole, each of said divided transistors having a predetermined limited width less than the width of said bipolar transistor so as to increase the operating speed of said bipolar transistor, said divided protection transistors having a substantially equal breakdown voltage of a junction between a collector region and said semiconductor substrate.
Specification
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- Resources
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Current AssigneePS4 Luxco S.a.r.l.
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Original AssigneeNEC Corporation
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InventorsNarita, Kaoru
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Primary Examiner(s)MINTEL, WILLIAM A
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Application NumberUS08/627,093Time in Patent Office657 DaysField of Search257/361, 257/362, 257/355, 257/356US Class Current257/355CPC Class CodesH01L 27/0259 using bipolar transistors a...
