EP0293588A2
Expired / Lapsed
EP
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Pedestal transistors and method of production thereof
Assignee: Motorola Solutions Inc
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Filing: 1988-04-21
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Granted: —
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Expires: 2008-04-21
Abstract
Abstract The present invention describes a method of producing MOS, Bipolar, or BiMOS pedestal transistors wherein the source, drain, and gate metals (57, 64) are in place prior to the source/drain diffusion (62) in a MOS transistor; and the emitter and base metals (57, 64) are in place before junction formation on the bipolar transistors. This is accomplished in MOS devices by a first blanket implantation of impurities into a first polysilicon layer (56) during processing and a second blanket implantation into a second polysilicon layer (63) subsequent to deposition of the silicide layers (57, 64). This is accomplished in bipolar devices by the above, or by blanket implantations subsequent to the deposition of the silicide layers (57, 64).
Inventors
- 👤 Israel Arnold Lesk
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 06:44
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/069; H10D; H10D10/00; H10D10/01; H10D10/051; H10D30/00; H10D30/01; H10D30/021; H10D30/027; H10D30/0273; H10D84/00; H10D84/01; H10D84/0107; H10D84/0109; H10D84/02; H10D84/03; H10D84/038; H10P; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/1414; H10P32/17; H10P32/171
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
171 words
A method of producing an MOS pedestal transistor on a substrate (10) having a pedestal (25) comprising the steps: depositing a first polysilicon layer (13) of a first conductivity type; depositing a first tungsten silicide layer (14) on said first polysilicon layer (13); depositing a silicon dioxide layer (15) on said first tungsten silicide layer (14); producing an opening (16) through said silicon dioxide (15), first tungsten silicide (14), and first polysilicon (13) layers to said pedestal (25) of said substrate (10), said opening (16) being defined by a side wall; forming a gate dielectric (17) on said pedestal (25); forming a side wall insulator (18) about said side wall defining said opening (16); depositing a second polysilicon layer (21); depositing a second tungsten silicide layer (22) on said second polysilicon layer (21); baking said MOS pedestal transistor causing a portion of said first impurity of said first polysilicon layer (13) to diffuse into a portion of said pedestal (25); and implanting a second impurity into said second polysilicon layer (21).
Claim 2
Independent Claim
171 words
A method of producing an MOS pedestal transistor on a substrate (10) having a pedestal (25) comprising the steps: depositing a first polysilicon layer (13) of a first conductivity type; depositing a first tungsten silicide layer (14) on said first polysilicon layer (13); depositing a silicon dioxide layer (15) on said first tungsten silicide layer (14); producing an opening (16) through said silicon dioxide (15), first tungsten silicide (14), and first polysilicon (13) layers to said pedestal (25) of said substrate (10), said opening (16) being defined by a side wall; forming a gate dielectric (17) on said pedestal (25); forming a side wall insulator (18) about said side wall defining said opening (16); depositing a second polysilicon layer (21); depositing a second tungsten silicide layer (22) on said second polysilicon layer (21); baking said MOS pedestal transistor causing a portion of said first impurity of said first polysilicon layer (13) to diffuse into a portion of said pedestal (25); and implanting a second impurity into said second polysilicon layer (21).
Claim 3
Dependent Claim
38 words
The method of claim 1 wherein said portion of said first impurity of said first polysilicon layer (13) to diffuse into said portion of said pedestal (25) forms a source and a drain of said MOS pedestal transistor.
Claim 4
Independent Claim
126 words
A method of producing a Bipolar pedestal transistor on a substrate (30) having a pedestal (45) comprising the steps: depositing a first polysilicon layer (33); depositing a first tungsten silicide layer (34) on said first polysilicon layer (33); depositing a silicon dioxide layer (35) on said first tungsten silicide layer (34); producing an opening (36) through said silicon dioxide (35), first tungsten silicide (34), and first polysilicon (33) layers to said pedestal (45) of said substrate (30), said opening (36) being defined by a side wall; forming a side wall insulator (38) about said side wall defining said opening (36); depositing a second polysilicon layer (41); depositing a second tungsten silicide layer (42) on said second polysilicon layer (41); forming a base; and forming an emitter.
Claim 5
Independent Claim
126 words
A method of producing a Bipolar pedestal transistor on a substrate (30) having a pedestal (45) comprising the steps: depositing a first polysilicon layer (33); depositing a first tungsten silicide layer (34) on said first polysilicon layer (33); depositing a silicon dioxide layer (35) on said first tungsten silicide layer (34); producing an opening (36) through said silicon dioxide (35), first tungsten silicide (34), and first polysilicon (33) layers to said pedestal (45) of said substrate (30), said opening (36) being defined by a side wall; forming a side wall insulator (38) about said side wall defining said opening (36); depositing a second polysilicon layer (41); depositing a second tungsten silicide layer (42) on said second polysilicon layer (41); forming a base; and forming an emitter.
Claim 6
Dependent Claim
41 words
The method of claim 3 wherein said step of forming a side wall insulator (38) comprises the step of oxidizing a portion of said first tungsten silicide (34) and first polysilicon (33) layers adjacent said side wall defining the opening (36).
Claim 7
Dependent Claim
74 words
The method of claim 3 or 4 wherein said step of forming a base comprises the steps of: blanket implanting a first impurity into said second tungsten silicide layer (42); and diffusing said first impurity through the second polysilicon layer (41) forming a base portion of said pedestal (45) adjacent said second polysilicon layer (41) and coupled to the region diffused from said first polysilicon layer (33) adjacent said portion of said pedestal (45).
Claim 8
Dependent Claim
60 words
The method of claim 3, 4 or 5 wherein said step of forming an emitter comprises the steps of: blanket implanting a second impurity into said second tungsten silicide layer (42); and diffusing it through the second polysilicon layer (41) and into said pedestal (45) to form an emitter portion of said pedestal (45) adjacent said second polysilicon layer (41).
Claim 9
Independent Claim
275 words
A method of producing a BiMOS pedestal transistor on a substrate (50) having first and second pedestals (55) comprising the steps: depositing a first polysilicon layer (56) of a first conductivity type; depositing a first tungsten silicide layer (57) on said first polysilicon layer (56); depositing a silicon dioxide layer (58) on said first tungsten silicide layer (57); producing a first and a second opening (59) through said silicon dioxide (58), first tungsten silicide (57), and first polysilicon (56) layers to said first and second pedestals (55) of said substrate (50), each of said first and second openings (59) being defined by side walls; forming a gate dielectric (60) on said first pedestal; forming a side wall insulator (61) about each of said side walls defining said first and second openings (59); depositing a second polysilicon layer (63); depositing a second tungsten silicide layer (64) on said second polysilicon layer (63); baking said BiMOS pedestal transistor causing a portion of said first impurity of said first polysilicon layer (56) to diffuse into a portion of said first and second pedestals (55) adjacent said first polysilicon layer (56); and implanting a second impurity of a first conductivity type into said second polysilicon layer (63); diffusing said second impurity through said second polysilicon layer (63) into a base portion of said second pedestal adjacent to said second polysilicon layer (63); implanting a third impurity of a second conductivity type into a Bipolar portion (52) of said second polysilicon layer (63); and diffusing said third impurity through said second polysilicon layer (63) into an emitter portion (68) of said second pedestal adjacent to said second polysilicon layer (63).
Claim 10
Independent Claim
275 words
A method of producing a BiMOS pedestal transistor on a substrate (50) having first and second pedestals (55) comprising the steps: depositing a first polysilicon layer (56) of a first conductivity type; depositing a first tungsten silicide layer (57) on said first polysilicon layer (56); depositing a silicon dioxide layer (58) on said first tungsten silicide layer (57); producing a first and a second opening (59) through said silicon dioxide (58), first tungsten silicide (57), and first polysilicon (56) layers to said first and second pedestals (55) of said substrate (50), each of said first and second openings (59) being defined by side walls; forming a gate dielectric (60) on said first pedestal; forming a side wall insulator (61) about each of said side walls defining said first and second openings (59); depositing a second polysilicon layer (63); depositing a second tungsten silicide layer (64) on said second polysilicon layer (63); baking said BiMOS pedestal transistor causing a portion of said first impurity of said first polysilicon layer (56) to diffuse into a portion of said first and second pedestals (55) adjacent said first polysilicon layer (56); and implanting a second impurity of a first conductivity type into said second polysilicon layer (63); diffusing said second impurity through said second polysilicon layer (63) into a base portion of said second pedestal adjacent to said second polysilicon layer (63); implanting a third impurity of a second conductivity type into a Bipolar portion (52) of said second polysilicon layer (63); and diffusing said third impurity through said second polysilicon layer (63) into an emitter portion (68) of said second pedestal adjacent to said second polysilicon layer (63).
Claim 11
Dependent Claim
35 words
The method of claim 7 wherein said steps of forming a gate dielectric (60) comprise the steps of oxidizing said first pedestal forming a layer of oxide (60) on a surface of said first pedestal.
Claim 12
Dependent Claim
45 words
The method of claim 7 or 8 wherein said steps of forming a side wall insulator comprises the steps of oxidizing a portion of said first tungsten silicide (57) and first polysilicon (56) layers adjacent said side walls defining said first and second openings (59).
Claim 13
Dependent Claim
46 words
The method of claim 7, 8 or 9 wherein said portion of said first impurity of said first polysilicon layer (56) to diffuse into said portion of said first pedestal forms a source and a drain of a MOS portion (53) of said BiMOS pedestal transistor.
References Cited (Backward Citations)
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