US4824797A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-aligned channel stop
Assignee: International Business Machines Corp
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Filing: 1985-10-31
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Granted: 1989-04-25
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Expires: 2005-10-31
Abstract
Abstract Disclosed is a process of forming channel stops which starts with a, for example, N type silicon substrate having on the surface thereof an insulator trench mask defining the region of silicon where an isolation trench is desired. A blockout layer having an opening in correspondence with the portion of the would-be silicon mesa where a channel stop is desired is formed. N type dopant is introduced into the exposed silicon followed by an anneal step to and vertically diffuse the dopant into the silicon body. The exposed silicon is etched forming a deep trench which delineates silicon mesa having at a section of the peripheral portion thereof a shallow and highly N doped region. Upon forming a pair of highly P doped regions on either side of the shallow highly N doped region, the latter functions as a channel stop to arrest charge leakage between the P doped regions due to parasitic FET action at the trench walls.
Inventors
- 👤 George R. Goth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:50
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0148; H10W10/10; H10W10/17
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
154 words
A method for forming a semiconductor structure having a self-aligned channel stop, comprising: providing a first conductivity type semiconductor body having on the surface thereof an insulator layer; forming in said insulator layer an opening to expose said body corresponding to where a trench of a predetermined length is desired; forming a blockout layer having an opening therein to limit the exposure of said body exposed by said opening in said insulator layer to a selected portion of said length; introducing dopant of the first conductivity type into said body exposed by the resultant of the openings in said insulator and blockout layer; annealing to diffuse said dopant into said body; and reactively ion etching said body exposed by the opening in said insulator layer to form said trench whereby is formed a highly doped first conductivity type channel stop in a surface region of the semiconductor body abutting a portion of said trench.
Claim 2
Independent Claim
154 words
A method for forming a semiconductor structure having a self-aligned channel stop, comprising: providing a first conductivity type semiconductor body having on the surface thereof an insulator layer; forming in said insulator layer an opening to expose said body corresponding to where a trench of a predetermined length is desired; forming a blockout layer having an opening therein to limit the exposure of said body exposed by said opening in said insulator layer to a selected portion of said length; introducing dopant of the first conductivity type into said body exposed by the resultant of the openings in said insulator and blockout layer; annealing to diffuse said dopant into said body; and reactively ion etching said body exposed by the opening in said insulator layer to form said trench whereby is formed a highly doped first conductivity type channel stop in a surface region of the semiconductor body abutting a portion of said trench.
Claim 3
Dependent Claim
13 words
The method as in claim 1 wherein said semiconductor body is monocrystalline silicon.
Claim 4
Dependent Claim
17 words
The method as in claim 2 wherein said insulator is composed of silicon dioxide and silicon nitride.
Claim 5
Dependent Claim
15 words
The method as in claim 3 wherein said dopant introduction is accomplished by ion implantation.
Claim 6
Dependent Claim
14 words
The method as in claim 3 wherein said dopant is of N conductivity type.
Claim 7
Dependent Claim
31 words
The method as in claim 2 further comprising etching said silicon body delineated by said trench to form a silicon mesa having at the upper peripheral sections thereof a channel stop.
Claim 8
Dependent Claim
11 words
The method as in claim 5 wherein said dopant is phosphorous.
Claim 9
Dependent Claim
28 words
The method as in claim 7 wherein the implantation energy and dose of said phosphorous ions are in the ranges of 30-180 Kev and 1-5×10 13 ions/sq.cm., respectively.
Claim 10
Dependent Claim
27 words
The method as in claim 1 wherein said dopant introduction comprises multiple ion implantation steps each involving a common dopant species, but different implantation energy and dose.
Claim 11
Dependent Claim
14 words
The method as in claim 3 wherein said blockout mask is composed of photoresist.
Claim 12
Independent Claim
211 words
A method for forming a first conductivity type channel stop in a semiconductor body, comprising: providing a first conductivity type semiconductor body having on the surface thereof a insulative layer; forming on said layer a mask having an opening corresponding to the portion of said body where a device isolation trench of a given length is desired; etching selectively said insulative layer to form an opening in correspondence with said mask opening and exposing said body thereunder; removing said mask; forming a blockout layer on the resulting structure, said blockout layer having an opening corresponding to a portion of said body exposed by the opening in said insulative layer to limit exposure of said body exposed by the opening in said insulative layer to a portion of said length; implanting first conductivity type ions into said body exposed by the resultant of openings in said blockout and insulative layers; thermally annealing the structure resulting after removal of said blockout mask to diffuse the implanted ions into the semiconductor body; and etching said body exposed by said opening in the insulative layer to form said trench and thereby obtain a first conductivity type semiconductor mesa having at least one shallow, highly doped first conductivity type channel stop at a peripheral region thereof.
Claim 13
Independent Claim
211 words
A method for forming a first conductivity type channel stop in a semiconductor body, comprising: providing a first conductivity type semiconductor body having on the surface thereof a insulative layer; forming on said layer a mask having an opening corresponding to the portion of said body where a device isolation trench of a given length is desired; etching selectively said insulative layer to form an opening in correspondence with said mask opening and exposing said body thereunder; removing said mask; forming a blockout layer on the resulting structure, said blockout layer having an opening corresponding to a portion of said body exposed by the opening in said insulative layer to limit exposure of said body exposed by the opening in said insulative layer to a portion of said length; implanting first conductivity type ions into said body exposed by the resultant of openings in said blockout and insulative layers; thermally annealing the structure resulting after removal of said blockout mask to diffuse the implanted ions into the semiconductor body; and etching said body exposed by said opening in the insulative layer to form said trench and thereby obtain a first conductivity type semiconductor mesa having at least one shallow, highly doped first conductivity type channel stop at a peripheral region thereof.
Claim 14
Dependent Claim
12 words
The method as in claim 11 wherein said blockout mask is photoresist.
Claim 15
Dependent Claim
37 words
The method as in claim 12 further comprising forming a pair of highly doped regions of a second conductivity type on the surface portion of said mesa on either side of and contiguous with said channel stop.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-24 | 1992-10-24 | 1993-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-24 | 1996-10-24 | 1997-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-24 | 2000-10-24 | 2001-04-25 | $7700.00 | Window Closed / Lapsed |