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US 6,025,615 AGranted
Microwave heterojunction bipolar transistors with emitters designed for high power applications and method for fabricating same
AssigneeTexas Instruments Incorporated
InventorsWilliam Uei-Chung Liu, Darrell Glenn Hill
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Abstract
In one form of the invention, an emitter structure for a bipolar transistor is disclosed. The structure is comprised of an emitter layer 6 of Al.sub.x Ga.sub.1-x As, where x>0.4, abutting a base layer 8.
Claims16
An emitter structure for a bipolar transistor, said structure comprising an emitter layer of Al.sub.x Ga.sub.1-x As, where x>0.5, adjacent a base layer whereby said emitter layer acts as a ballast resistor and as the active emitter for said transistor.
A bipolar transistor comprising:
- a substrate;
- a subcollector layer;
- a collector layer;
- a base layer;
- an emitter layer comprising Al.sub.x Ga.sub.1-x As, where x>0.5.
2 more elements
An emitter structure for a bipolar transistor, said structure comprising:
- a ballast resistor layer of Al.sub.x Ga.sub.1-x As, where x>0.4;
- and
- an active emitter layer of Al.sub.x Ga.sub.1-x As, where x.ltoreq.0.4, adjacent a base layer.
Dependencies are inferred from the claim text.