← Back to Patent Explorer
US4555843A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of fabricating density intensive non-self-aligned stacked CMOS

Assignee: Texas Instruments Inc
•
Filing: 1984-04-27
•
Granted: 1985-12-03
•
Expires: 2004-04-27
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A stacked CMOS structure is disclosed which uses buried N++ source and drain for the non-self-aligned bulk N-channel driver devices together with an oversized polygate on which a non-self aligned P-channel load device is made from a second layer of poly or recrystallized poly. The non-self aligned pair of stacked devices provides increased density of devices per unit area with a simple process at the cost of increased gate to source and gate to drain parasitic capicitances.

Inventors

  • 👤 Satwinder D. S. Malhi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 03:56
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/02; H10D84/03; H10D84/038; H10D88/00; H10D88/01; Y; Y10; Y10S; Y10S148/00; Y10S148/082; Y10S148/164

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 267 words
A method of fabricating stacked field effect semiconductor devices with channel length L, channel width W and with a maximum patterning alignment error S, comprising the steps of: (a) patterning first source and drain regions in a semiconductor substrate, said first source and drain regions of width W and defining a first channel region in said substrate of length L and width W, (b) forming a first insulating layer on said substrate and covering said first channel region, (c) patterning a conducting strip of width of L+2S on said insulating layer, said conducting strip oriented perpendicular to said length L of said first channel region and aligned without regard to S to centrally cover said first channel region, (d) forming a second insulating layer on said conducting strip and connecting to said first insulating layer, (e) patterning a semiconducting strip of width W on said insulating layers, said semiconducting strip oriented parallel to said length L of said first channel region and aligned without regard to S to cover said first channel region, (f) patterning second source and drain regions in said semiconducting strip, said second source and drain regions defining a second channel region of length L oriented perpendicular to said conducting strip and aligned without regard to S to be centrally over said conducting strip, and (g) said first source and drain regions, said first channel region, and said conducting strip forming a first field effect semiconductor device, and said second source and drain regions, said second channel region, and said conducting strip forming a secnd field effect semiconducting device stacked on said first device.
Claim 2
Independent Claim 267 words
A method of fabricating stacked field effect semiconductor devices with channel length L, channel width W and with a maximum patterning alignment error S, comprising the steps of: (a) patterning first source and drain regions in a semiconductor substrate, said first source and drain regions of width W and defining a first channel region in said substrate of length L and width W, (b) forming a first insulating layer on said substrate and covering said first channel region, (c) patterning a conducting strip of width of L+2S on said insulating layer, said conducting strip oriented perpendicular to said length L of said first channel region and aligned without regard to S to centrally cover said first channel region, (d) forming a second insulating layer on said conducting strip and connecting to said first insulating layer, (e) patterning a semiconducting strip of width W on said insulating layers, said semiconducting strip oriented parallel to said length L of said first channel region and aligned without regard to S to cover said first channel region, (f) patterning second source and drain regions in said semiconducting strip, said second source and drain regions defining a second channel region of length L oriented perpendicular to said conducting strip and aligned without regard to S to be centrally over said conducting strip, and (g) said first source and drain regions, said first channel region, and said conducting strip forming a first field effect semiconductor device, and said second source and drain regions, said second channel region, and said conducting strip forming a secnd field effect semiconducting device stacked on said first device.
Claim 3
Independent Claim 273 words
A method of fabricating stacked field effect semiconductor devices with channel length L, channel width W, in the underlying device, channel length K, channel width V in the overlying device, and with a maximum patterning alignment error S, comprising the steps of: (a) patterning first source and drain regions in a semiconductor substrate, said first source and drain regions of width W and defining a first channel region in said substrate of length L and width W, (b) forming a first insulating layer on said substrate and covering said first channel region, (c) patterning a conducting strip of width at least the larger of L+2S and K+2S on said insulating layer, said conducting strip oriented perpendicular to said length L of said first channel region and covering said first channel region, (d) forming a second insulating layer on said conducting strip and connecting to said first insulating layer, (e) patterning a semiconducting strip of width V on said insulating layers, said semiconducting strip oriented parallel to said length L of said first channel region and at least partially covering said first channel region, (f) patterning second source and drain regions in said semiconducting strip, said second source and drain regions defining a second channel region of length K and width V and oriented perpendicular to said conducting strip and over said conducting strip, and (g) said first source and drain regions, said first channel region, and said conducting strip forming a first field effect semiconductor device, and said second source and drain regions, said second chanel region, and said conducting strip forming a second field effect semiconducting device stacked on said first device.
Claim 4
Independent Claim 273 words
A method of fabricating stacked field effect semiconductor devices with channel length L, channel width W, in the underlying device, channel length K, channel width V in the overlying device, and with a maximum patterning alignment error S, comprising the steps of: (a) patterning first source and drain regions in a semiconductor substrate, said first source and drain regions of width W and defining a first channel region in said substrate of length L and width W, (b) forming a first insulating layer on said substrate and covering said first channel region, (c) patterning a conducting strip of width at least the larger of L+2S and K+2S on said insulating layer, said conducting strip oriented perpendicular to said length L of said first channel region and covering said first channel region, (d) forming a second insulating layer on said conducting strip and connecting to said first insulating layer, (e) patterning a semiconducting strip of width V on said insulating layers, said semiconducting strip oriented parallel to said length L of said first channel region and at least partially covering said first channel region, (f) patterning second source and drain regions in said semiconducting strip, said second source and drain regions defining a second channel region of length K and width V and oriented perpendicular to said conducting strip and over said conducting strip, and (g) said first source and drain regions, said first channel region, and said conducting strip forming a first field effect semiconductor device, and said second source and drain regions, said second chanel region, and said conducting strip forming a second field effect semiconducting device stacked on said first device.
Claim 5
Dependent Claim 21 words
The method of claim 2, wherein: (a) said semiconductor substrate comprises crystalline silicon, and (b) said semiconducting strip comprises polycrystalline silicon.
Claim 6
Dependent Claim 23 words
The method of claim 2, wherein: (a) said first device is a n-channel device, and (b) said second device is a p-channel device.
Claim 7
Dependent Claim 27 words
The method of claim 4, wherein: (a) said p-channel device operates as a depletion mode device, and (b) said n-channel device operates as an enhancement mode device.

References Cited (Backward Citations)

US4467518A Cited
US4476475A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1988-12-02 1989-06-03 1989-12-03 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1992-12-02 1993-06-03 1993-12-03 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1996-12-02 1997-06-03 1997-12-03 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag