US3755001A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making semiconductor devices with selective doping and selective oxidation
Assignee: US Philips Corp
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Filing: 1971-07-08
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Granted: 1973-08-28
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Expires: 1991-07-08
Abstract
Abstract A method of manufacturing a semiconductor device having an inset oxide pattern obtained by local oxidation, which pattern is bounded only partly by a doped surface zone. According to the invention a first mask is provided on the semiconductor surface after which etching is carried out so that a freely projecting edge of said mask is formed by underetching. During the local doping of the etched surface the masking provided by said edge is used directly or indirectly after which the oxide pattern is provided.
Inventors
- 👤 J Appels
- 👤 E Kooi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:36
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/10; H10W10/13; H10P; H10P14/00; H10P14/60; H10P14/61; H10W10/01; H10W10/011; H10W10/012; H10W10/0121; H10W10/0124; H10W10/0125; H10W10/0126; H10W15/00; H10W15/01; Y; Y10; Y10S; Y10S148/00; Y10S148/043; Y10S148/051; Y10S148/085; Y10S148/103; Y10S148/106; Y10S148/117; Y10S148/141; Y10S148/143; Y10S148/145; Y10S438/00; Y10S438/942; Y10S438/944
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
25 words
A method as claimed in claim 1 wherein the oxidizing step is continued until the resulting recess is filled up substantially entirely by grown oxide.
Claim 2
Dependent Claim
52 words
A method as claimed in claim 1 wherein the semiconductor body portion bordering the recess is locally doped by directing thereon a stream of activators transverse to the first mask, the parts of the body surface present below the projecting edge of the first mask being masked against doping by the activators.
Claim 3
Dependent Claim
73 words
A method as claimed in claim 1 wherein a second mask is provided on the surface of the body part bordering the recess using the masking provided by the freely projecting edge of the first mask, the circumference of said second mask within the recess coinciding in projection substantially with the circumference of the first mask, after which the unmasked parts of the semiconductor body surface bordering the recess are doped with activators.
Claim 4
Dependent Claim
36 words
A method as claimed in claim 4 wherein the second mask is provided on only those surface parts of the body part bordering the recess which are present below the projecting edge of the first mask.
Claim 5
Dependent Claim
37 words
A method as claimed in claim 4 wherein the second mask is provided on only those surface parts of the body part bordering the recess which are not present below the projecting edge of the first mask.
Claim 6
Dependent Claim
101 words
A method as claimed in claim 6 wherein the second mask is formed by a first layer part which masks against activators and which is provided on the whole surface of the body part bordering the recess, and by a second layer part which masks against etching and which is deposited from a direction transverse to the first mask on those parts of the first layer part which not masked by the projecting edge of the first mask, the exposed first layer portions are then removed by etching exposing a part of the surface of the body part bordering the recess.
Claim 7
Dependent Claim
110 words
A method as claimed in claim 4 wherein the first mask also masks against radiation to which a photoresist is sensitive, a masking layer is provided on the whole surface of the body part bordering the recess, a photoresist is provided covering the said masking layer, the said photoresist is subjected to radiation exposing the photoresist except where masked by the projecting edge of the first mask, one of the exposed and unexposed photoresist portions is removed exposing part of the masking layer, the exposed part of the masking layer is removed, and the remaining photoresist is then removed, the remaining parts of the masking layer forming the second mask.
Claim 8
Dependent Claim
43 words
A method as claimed in claim 4 wherein after provision of the second mask and prior to the doping step, the parts of the semiconductor body which are exposed by the second mask are subjected to a further etching treatment to remove material.
Claim 9
Dependent Claim
15 words
A method as claimed in claim 4 wherein the second mask compriSes a metal layer.
Claim 10
Dependent Claim
28 words
A method as claimed in claim 1 wherein the body material removal is carried out by etching the body surface which is not covered by the first mask.
Claim 11
Dependent Claim
17 words
A method as claimed in claim 1 wherein the activators doping is carried out by ion implantation.
Claim 12
Dependent Claim
38 words
A method as claimed in claim 1 wherein the recess is ring-shaped and entirely surrounds an island-shaped region of the semiconductor body, and at least one semiconductor circuit element is at least partly provided in said island-shaped region.
Claim 13
Dependent Claim
85 words
A method as claimed in claim 13 wherein the recess is provided in an epitaxial layer of a first conductivity type grown on a substrate of the first conductivity type, a buried layer of a second opposite conductivity type is provided between the epitaxial layer and the substrate so as to extend at least below the said island-shaped region, and the said doped surface zone is of the second conductivity type and is provided over such a large depth as to adjoin the buried layer.
Claim 14
Dependent Claim
51 words
A method as claimed in claim 13 wherein a semiconductor element is provided having at least a p-n junction extending substantially parallel to the semiconductor surface present outside the recess, and the inset oxide is grown to at least cover the line of intersection of said p-n junction with the recess.
Claim 15
Dependent Claim
29 words
A method as claimed in claim 1 wherein the activator doping is with activators forming the same type conductivity as that of the adjoining region of the semiconductor body.
Claim 16
Dependent Claim
21 words
A method as claimed in claim 1 wherein the recess is provided in an epitaxial layer present on a semiconductor substrate.
Claim 17
Dependent Claim
31 words
A method as claimed in claim 17 wherein the doped surface zone bordering the recess is doped by an activator of a conductivity type opposite to that of the epitaxial layer.
Claim 18
Dependent Claim
44 words
A method as claimed in claim 18 wherein the epitaxial layer is of a first conductivity type and the substrate is of a second opposite conductivity type, and the said doped surface zone extends through the epitaxial layer so as to adjoin the substrate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |