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US 5,387,813 AGranted
Transistors with emitters having at least three sides
AssigneeNational Semiconductor Corporation
InventorsAli A. Iranmanesh, David E. Bien, Michael J. Grubisich
Life of this patent
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Abstract
A bipolar transistor is provided in which the base-emitter junctions do not traverse the base but terminate inside the top surface of the base. The transistor has long emitter perimeter available for current flow and more than two emitter sides (e.g., three sides) available for current flow, which allows obtaining a low base resistance, a low emitter resistance, a low collector resistance, a low base-collector capacitance, and a small size.
Claims22
A transistor comprising:
- a collector;
- a base overlying and contacting said collector, said base having a top surface, said top surface having a boundary, said base comprising:
- (1) a semiconductor region, and (2) a conductive metal-containing region overlying and contacting said semiconductor region;
- a first emitter overlying said top surface of said base, said first emitter comprising semiconductor material which extends up higher than said base, said first emitter and said base forming a first contiguous base-emitter junction which junction extends from said boundary of said top surface inside said top surface and terminates inside said rod surface, said junction having in plan view at least three sides extending inside said top surface;
- and
- a second emitter spaced from said first emitter, said second emitter overlying said top surface of said base, said second emitter comprising semiconductor material which extends up higher than said base, said second emitter and said base forming a second contiguous base-emitter junction which junction extends from said boundary of said top surface inside said top surface and terminates inside said top surface, said second junction having in plan view at least three sides extending inside said top surface,
- wherein said conductive metal-containing region is spaced from said first and second emitters, and said conductive metal-containing region extends along at least three sides of each of said first and second base-emitter junctions.
4 more elements
Dependencies are inferred from the claim text.