← Back to Patent Explorer
US4809051A Expired / Lapsed US ⏱️ 0.0 years remaining

Vertical punch-through cell

Assignee: National Semiconductor Corp
•
Filing: 1987-08-06
•
Granted: 1989-02-28
•
Expires: 2007-08-06
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract The present invention provides a vertical punch-through cell comprising a silicon substrate, an epitaxial silicon layer overlying the substrate, an N+ buried column line formed at the interface between the substrate and the epitaxial layer, an N+ diffusion region formed above and spaced apart from the buried column line at the surface of the epitaxial layer, a field oxide layer formed over the epitaxial layer and having an contact opening formed therein over the N+ diffusion region, a polysilicon layer formed on the surface of the field oxide layer to extend through the contact opening to make contact with the N diffusion region, a layer of dielectric material formed over the polysilicon layer, and a layer of conductive material formed over the dielectric material.

Inventors

  • 👤 Grigory Kogan

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 05:51
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/351; H10D62/386

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 130 words
A vertical punch-through cell comprising: (a) a silicon substrate; ( b) an epitaxial silicon layer overlying the substrate; (c) an N+ buried column line formed at the interface between the substrate and the epitaxial layer; (d) an N+ diffusion region formed above and spaced apart from the buried column line at the surface of the epitaxial layer; (e) a field oxide layer formed over the epitaxial layer and having a contact opening formed therein over the N+ diffusion region; (f) a polysilicon layer formed on the surface of the field oxide layer to extend through the contact opening to make contact with the N+ diffusion region; (g) a layer of dielectric material formed over the polysilicon layer; and (h) a layer of conductive material formed over the layer dielectric material.
Claim 2
Dependent Claim 130 words
A vertical punch-through cell comprising: (a) a silicon substrate; ( b) an epitaxial silicon layer overlying the substrate; (c) an N+ buried column line formed at the interface between the substrate and the epitaxial layer; (d) an N+ diffusion region formed above and spaced apart from the buried column line at the surface of the epitaxial layer; (e) a field oxide layer formed over the epitaxial layer and having a contact opening formed therein over the N+ diffusion region; (f) a polysilicon layer formed on the surface of the field oxide layer to extend through the contact opening to make contact with the N+ diffusion region; (g) a layer of dielectric material formed over the polysilicon layer; and (h) a layer of conductive material formed over the layer dielectric material.
Claim 3
Dependent Claim 15 words
A vertical punch-through cell as in claim 1 wherein the dielectric material is silicon nitride.
Claim 4
Dependent Claim 14 words
A vertical punch-through cell as in claim 2 wherein the conductive material is metal.
Claim 5
Dependent Claim 14 words
A vertical punch-through cell as in claim 2 wherein the conductive material is polysilicon.

References Cited (Backward Citations)

US4471368A Cited
US4649406A Cited
JPS60198771A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-02-28 1992-08-29 1993-02-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-02-28 1996-08-29 1997-02-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-02-28 2000-08-29 2001-02-28 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag