US5571732A
Expired / Lapsed
US
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Method for fabricating a bipolar transistor
Assignee: Texas Instruments Inc
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Filing: 1995-06-07
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Granted: 1996-11-05
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Expires: 2015-06-07
Abstract
Abstract In one form of the invention, a bipolar transistor is disclosed, the transistor comprising a GaAs substrate in the (111) orientation 100, and an InGaAs region 106 over the substrate 100, the InGaAs region 106 having a first surface and a second surface, wherein the mole fraction of In in the InGaAs region 106 varies from said first surface to said second surface.
Inventors
- 👤 William U. Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:46
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/021; H10D10/80; H10D10/821; H10D62/00; H10D62/80; H10D62/85; H10D62/852; Y; Y10; Y10S; Y10S148/00; Y10S148/072; Y10S438/00; Y10S438/936
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
58 words
A method for fabricating a bipolar transistor comprising the steps of: providing a GaAs substrate in the (111) orientation; and forming an InGaAs region over said substrate, said InGaAs region having a first surface and a second surface, wherein the mole fraction of the indium in said InGaAs region varies from said first surface to said second surface.
Claim 2
Independent Claim
58 words
A method for fabricating a bipolar transistor comprising the steps of: providing a GaAs substrate in the (111) orientation; and forming an InGaAs region over said substrate, said InGaAs region having a first surface and a second surface, wherein the mole fraction of the indium in said InGaAs region varies from said first surface to said second surface.
Claim 3
Dependent Claim
33 words
The method of claim 1 wherein said step of forming an InGaAs region comprises varying the In mole fraction from approximately 0% at said first surface to approximately 15% at said second surface.
Claim 4
Dependent Claim
44 words
The method of claim 1 wherein said step of providing a GaAs substrate in the (111) orientation comprises providing a GaAs substrate is in the (111)B orientation and wherein said step of forming an InGaAs region includes the step of doping said region n-type.
Claim 5
Dependent Claim
44 words
The method of claim 1 wherein said step of providing a GaAs substrate in the (111) orientation comprises providing a GaAs substrate is in the (111)A orientation and wherein said step of forming an InGaAs region includes the step of doping said region p-type.
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein said step of forming an InGaAs region comprises varying the In mole fraction linearly from said first surface to said second surface.
Claim 7
Independent Claim
117 words
A method for fabricating a bipolar transistor comprising the steps of: forming an InGaAs base region between a collector region of a first material and an emitter region of a second material, said InGaAs base region having an indium mole fraction that increases from an interface between said base and collector regions to an interface between said base and emitter regions, and further wherein said increasing mole fraction establishes an electric field that opposes carrier transport through said InGaAs region from said emitter to said collector; and forming said InGaAs region over a GaAs substrate of (111) orientation, thereby establishing a piezoelectric field in said InGaAs base region in a direction opposite that of said electric field.
Claim 8
Independent Claim
117 words
A method for fabricating a bipolar transistor comprising the steps of: forming an InGaAs base region between a collector region of a first material and an emitter region of a second material, said InGaAs base region having an indium mole fraction that increases from an interface between said base and collector regions to an interface between said base and emitter regions, and further wherein said increasing mole fraction establishes an electric field that opposes carrier transport through said InGaAs region from said emitter to said collector; and forming said InGaAs region over a GaAs substrate of (111) orientation, thereby establishing a piezoelectric field in said InGaAs base region in a direction opposite that of said electric field.
Claim 9
Dependent Claim
37 words
The method of claim 6 wherein said InGaAs region wherein said step of forming an InGaAs region comprises varying the In mole fraction from approximately 0% at said collector-base interface to approximately 15% at said base-emitter interface.
Claim 10
Dependent Claim
44 words
The method of claim 6 wherein said step of forming said GaAs substrate in the (111) orientation comprises providing a GaAs substrate is in the (111)B orientation and wherein said step of forming said InGaAs region includes the step of doping said region n-type.
Claim 11
Dependent Claim
44 words
The method of claim 6 wherein said step of forming said GaAs substrate in the (111) orientation comprises providing a GaAs substrate is in the (111)A orientation and wherein said step of forming said InGaAs region includes the step of doping said region p-type.
Claim 12
Dependent Claim
14 words
The method of claim 6 wherein said first and second materials are the same.
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