US5219783A
Expired / Lapsed
US
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Method of making semiconductor well structure
Assignee: Texas Instruments Inc
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Filing: 1992-03-20
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Granted: 1993-06-15
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Expires: 2012-03-20
Abstract
Abstract A method of forming doped well regions in a semiconductor layer 14 is disclosed herein. At least one n-doped region 30 and at least one p-doped region 36 are formed in the semiconductor layer 14. The n-doped region 30 is separated from the p-doped region 36 by a separation region 39. An oxide layer 32 (38), for example silicon dioxide, is formed over the n-doped region 30 and p-doped region (36) but not over the separation region 39. The semiconductor layer 14 is then heated (e.g., at a temperature of less than 1150° C.) in a nitridizing environment such as ammonia. Other structures and methods are also disclosed.
Inventors
- 👤 Mehrdad M. Moslehi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:19
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0191; H10D84/02; H10D84/03; H10D84/038; H10D84/80; H10D84/82; H10D84/83; H10D84/85; H10P; H10P14/00; H10P14/40; H10P14/416; H10P14/60; H10P14/63; H10P14/6326; H10P14/6349; H10P30/00; H10P30/20; H10P30/22; H10P32/00; H10P32/10; H10P32/14; H10P32/1404; H10P32/1406; H10P32/17; H10P32/171; H10P76/00; H10P76/40; H10P76/408; H10P76/4085; H10P95/00; H10P95/90; H10D84/859; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/92
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
117 words
A method of forming doped N and P-wells in a silicon layer comprising the steps of: forming at least one n-doped region and at least one p-doped region in said silicon layer, said N-doped region separated from said P-doped region by a N-to-P well separation region; forming a silicon dioxide layer over said at least one N-doped region and over said at least one P-doped region but not over said separation region such that an upper surface of said separation region comprises an exposed semiconductor surface; and heating said silicon layer in a nitridizing environment wherein vertical diffusion of dopants is enhanced in said well regions and lateral diffusion of dopants into said separation region is retarded.
Claim 2
Independent Claim
117 words
A method of forming doped N and P-wells in a silicon layer comprising the steps of: forming at least one n-doped region and at least one p-doped region in said silicon layer, said N-doped region separated from said P-doped region by a N-to-P well separation region; forming a silicon dioxide layer over said at least one N-doped region and over said at least one P-doped region but not over said separation region such that an upper surface of said separation region comprises an exposed semiconductor surface; and heating said silicon layer in a nitridizing environment wherein vertical diffusion of dopants is enhanced in said well regions and lateral diffusion of dopants into said separation region is retarded.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein said nitridizing environment comprises an environment with an ammonia ambient.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein said heating step comprises heating to a temperature between about 1000° and 1150° C.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein said heating step comprises heating for a period of less than ten minutes.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein said N-doped region comprises a region doped with phosphorus.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein said P-doped region comprises a region doped with boron.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein said silicon layer comprises an epitaxially grown silicon layer.
Claim 9
Dependent Claim
16 words
The method of claim 1 wherein said heating step is performed in rapid thermal processing equipment.
Claim 10
Dependent Claim
27 words
The method of claim 1 wherein said step of forming at least one N-doped and at least one P-doped region comprises using only one microlithography patterning step.
Claim 11
Dependent Claim
15 words
The method of claim 1 wherein said separation region is doped to a selected level.
Claim 12
Dependent Claim
14 words
The method of claim 1 wherein said semiconductor layer comprises a doped semiconductor layer.
Claim 13
Independent Claim
121 words
A method of forming doped well regions in a silicon layer comprising the steps of: forming a multilayer structure on the surface of said silicon layer; etching a portion of said multilayer structure to define a first doped well region beneath the remaining portion of said multilayer structure and to expose a second doped well region; forming well-to-well separation regions adjacent said remaining portion of said multilayer structure; doping said second well doped region; forming a silicon dioxide layer over said second doped well region; removing at least a portion of said remaining portion of said multilayer structure; doping said first doped well region; and heating said silicon layer in a nitridizing environment such that dopants diffuse into said silicon layer.
Claim 14
Independent Claim
121 words
A method of forming doped well regions in a silicon layer comprising the steps of: forming a multilayer structure on the surface of said silicon layer; etching a portion of said multilayer structure to define a first doped well region beneath the remaining portion of said multilayer structure and to expose a second doped well region; forming well-to-well separation regions adjacent said remaining portion of said multilayer structure; doping said second well doped region; forming a silicon dioxide layer over said second doped well region; removing at least a portion of said remaining portion of said multilayer structure; doping said first doped well region; and heating said silicon layer in a nitridizing environment such that dopants diffuse into said silicon layer.
Claim 15
Dependent Claim
31 words
The method of claim 12 wherein said multilayer structure comprises an a first oxide layer, a first polysilicon layer, a second oxide layer, a second polysilicon layer and a nitride layer.
Claim 16
Dependent Claim
16 words
The method of claim 12 wherein said nitridizing environment comprises a environment with an ammonia ambient.
Claim 17
Dependent Claim
19 words
The method of claim 12 wherein said heating step comprises heating to a temperature less than about 1150° C.
Claim 18
Dependent Claim
19 words
The method of claim 12 wherein said heating step comprises heating for a period of less than ten minutes.
Claim 19
Dependent Claim
16 words
The method of claim 12 wherein said first well region comprises a region doped with phosphorus.
Claim 20
Dependent Claim
16 words
The method of claim 17 wherein said second well region comprises a region doped with boron.
Claim 21
Dependent Claim
15 words
The method of claim 12 wherein said silicon layer comprises an epitaxially grown silicon layer.
Claim 22
Dependent Claim
25 words
The method of claim 12 wherein said first well region is doped with N-type impurities and said second well region is doped with P-type impurities.
Claim 23
Independent Claim
157 words
A method of forming a doped well in a silicon layer comprising the steps of: forming a first silicon dioxide layer on the surface of said silicon layer; forming a first polysilicon layer on said first silicon dioxide layer; forming a second silicon dioxide layer on said first polysilicon layer; forming a second polysilicon layer on said second silicon dioxide layer; forming a silicon nitride layer on said second polysilicon layer; etching said silicon nitride layer and said second polysilicon layer to define a first well region beneath the remaining portion of said nitride layer and said first polysilicon layer; forming sidewall spacers adjacent said remaining portion; doping a second well region not beneath said remaining portion; forming a third silicon dioxide layer over said second well region; removing said remaining portion; doping said first well region; and heating said silicon layer in an ammonia ambient environment such that dopants tend to diffuse into said silicon layer.
Claim 24
Independent Claim
157 words
A method of forming a doped well in a silicon layer comprising the steps of: forming a first silicon dioxide layer on the surface of said silicon layer; forming a first polysilicon layer on said first silicon dioxide layer; forming a second silicon dioxide layer on said first polysilicon layer; forming a second polysilicon layer on said second silicon dioxide layer; forming a silicon nitride layer on said second polysilicon layer; etching said silicon nitride layer and said second polysilicon layer to define a first well region beneath the remaining portion of said nitride layer and said first polysilicon layer; forming sidewall spacers adjacent said remaining portion; doping a second well region not beneath said remaining portion; forming a third silicon dioxide layer over said second well region; removing said remaining portion; doping said first well region; and heating said silicon layer in an ammonia ambient environment such that dopants tend to diffuse into said silicon layer.
Claim 25
Dependent Claim
18 words
The method of claim 21 wherein said semiconductor layer comprises silicon and said oxide layers comprises silicon dioxide.
Claim 26
Dependent Claim
15 words
The method of claim 22 wherein said first silicon dioxide is formed by thermal oxidation.
Claim 27
Dependent Claim
27 words
The method of claim 21 wherein said steps of forming a silicon dioxide layer, forming a polysilicon layer and forming a silicon nitride layer comprise deposition steps.
References Cited (Backward Citations)
US4013484A
Cited
US4889828A
Cited
US5021358A
Cited
US5071777A
Cited
US4968639A
Cited
JPH0388363A
Cited
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