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US 5,684,310 AGranted
Multiple layer wide bandgap collector structure for bipolar transistors
AssigneeTexas Instruments Incorporated
InventorWilliam Uei-Chunt Liu
Life of this patent
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Abstract
Generally, and in one form of the invention, a multiple layer wide bandgap collector structure is provided which comprises a relatively thin, highly doped layer 12 and a relatively thick, low doped or non-intentionally doped layer 14. Other devices, systems and methods are also disclosed.
Claims23
A bipolar transistor comprising:
- a substrate:
- a subcollector layer disposed on said substrate;
- a first collector layer disposed on said subcollector layer, said first collector layer being relatively thick and having a dopant concentration of <1.times.10.sup.16 atoms/cm.sup.3 ;
- a second collector layer disposed on said first collector layer, said second collector layer being relatively thin and highly doped, said second collector layer having a graded semiconductor composition;
- a base layer disposed on said second collector layer, wherein said first collector layer has a wider energy bandgap than said base layer;
- and
- an emitter layer disposed on said base layer.
4 more elements
A bipolar transistor comprising:
- a substrate;
- a subcollector layer disposed over said substrate;
- a first collector layer formed of a first semiconductor material disposed over said subcollector layer, said first collector layer being relatively thick and having a dopant concentration of <1.times.10.sup.16 atoms/cm.sup.3 ;
- a second collector layer formed of a second semiconductor material disposed over said first collector layer, said second collector layer being relatively thin and highly doped;
- a base layer formed of a third semiconductor material disposed over said second collector layer;
- and
- an emitter layer disposed over said base layer, wherein the bandgap of said first semiconductor material is wider than that of said third semiconductor material.
4 more elements
A bipolar transistor comprising:
- a substrate:
- a subcollector layer disposed on said substrate;
- a first collector layer disposed on said subcollector layer, said first collector layer being relatively thick and having a dopant concentration of <1.times.10.sup.16 atoms/cm.sup.3 ;
- a second collector layer disposed on said first collector layer, said second collector layer being relatively thin and highly doped;
- a base layer disposed on said second collector layer, wherein said first collector layer has a wider energy bandgap than said base layer;
- and
- an emitter layer disposed on said base layer.
4 more elements
A bipolar transistor comprising:
- a substrate;
- a subcollector layer disposed over said substrate;
- a first collector layer formed of AlAs disposed over said subcollector layer, said first collector layer being relatively thick and having a dopant concentration of <1.times.10.sup.16 atoms/cm.sup.3 ;
- a second collector layer disposed over said first collector layer, said second collector layer being formed of a semiconductor material which is graded from AlAs at a first surface to GaAs at a second surface, said second collector layer being relatively thin and highly doped;
- a base layer formed of GaAs disposed over said second collector layer;
- and
- an emitter layer disposed over said base layer.
4 more elements
A bipolar transistor comprising:
- a substrate;
- a subcollector layer disposed over said substrate;
- a first collector layer formed of AlAs disposed over said subcollector layer, said first collector layer being relatively thick and low doped or non-intentionally doped;
- a second collector layer disposed over said first collector layer, said second collector layer being formed of a semiconductor material which is graded from AlAs at a first surface to GaAs at a second surface, said second collector layer being relatively thin and having a dopant concentration of >1.times.10.sup.17 atoms/cm.sup.3 ;
- a base layer formed of GaAs disposed over said second collector layer;
- and
- an emitter layer disposed over said base layer.
4 more elements
Dependencies are inferred from the claim text.