Patent US5381794A successfully refreshed from Google Patents.
US4289550A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming closely spaced device regions utilizing selective etching and diffusion
Assignee: Raytheon Co
•
Filing: 1979-05-25
•
Granted: 1981-09-15
•
Expires: 1999-05-25
Abstract
Abstract A semiconductor structure is provided by forming an isolation region in a portion of a semiconductor layer, forming a doped region in the semiconductor layer adjacent the isolation region, such doped region having a conductivity type opposite the conductivity type of the semiconductor layer, selectively masking a surface of the semiconductor layer exposing a portion of the doped region adjacent to the isolation region, and selectively etching the exposed portions of the adjacent doped region forming a depression having converging side walls separated from the isolation region by portions of the doped region. The semiconductor layer is an epitaxial layer providing the collector region of a transistor. The bottom portion of the depression is lightly doped to provide an active base region for the transistor. The active base region is electrically connected to the base contact through the more heavily doped region formed in the semiconductor layer. A doped polycrystalline silicon layer is formed over the bottom portion of the depression in contact with the active base region to provide an emitter contact for the transistor.
Inventors
- 👤 Wolfgang M. Feist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:27
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/177; H10D10/00; H10D10/80; H10D10/821; H10D10/861; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0121; H10W10/0124; H10W10/0125; H10W10/0126; H10W10/10; H10W10/13; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/106; Y10S148/168
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
88 words
A method for forming a semiconductor structure comprising the steps of: (a) forming an isolation region having an insulating material in a portion of a semiconductor layer; (b) forming a doped region in the semiconductor layer contiguous to the isolation region; (c) bringing an etchant into contact with a surface portion of the doped region and a contiguous surface portion of the isolation region; and (d) selectively etching the doped region forming a depression having wall portions separated from the isolation region by portions of the doped region.
Claim 2
Independent Claim
88 words
A method for forming a semiconductor structure comprising the steps of: (a) forming an isolation region having an insulating material in a portion of a semiconductor layer; (b) forming a doped region in the semiconductor layer contiguous to the isolation region; (c) bringing an etchant into contact with a surface portion of the doped region and a contiguous surface portion of the isolation region; and (d) selectively etching the doped region forming a depression having wall portions separated from the isolation region by portions of the doped region.
Claim 3
Dependent Claim
13 words
The method recited in claim 1 wherein the etchant is an anisotropic etchant.
Claim 4
Dependent Claim
32 words
The method recited in claim 1 wherein the etching step includes the step of stopping such etching when a bottom portion of the depression is beneath the bottom of the doped region.
Claim 5
Dependent Claim
28 words
The method recited in claim 3 including the step of providing particles into the portion of the semiconductor layer disposed beneath the bottom portion of the etched depression.
Claim 6
Independent Claim
115 words
A method for forming a semiconductor structure comprising the steps of: (a) providing a semiconductor having a first conductivity type; (b) forming an isolation region having an insulating material in a portion of the semiconductor; (c) forming a doped region in the semiconductor having a portion thereof contiguous to the isolation region, such doped region being formed with a conductivity type opposite the first conductivity type; (d) bringing an etchant into contact with a surface portion of the doped region and a contiguous surface portion of the isolation region; and (e) selectively etching the doped region forming a depression with converging side wall portions separated from the isolation region by portions of the doped region.
Claim 7
Independent Claim
115 words
A method for forming a semiconductor structure comprising the steps of: (a) providing a semiconductor having a first conductivity type; (b) forming an isolation region having an insulating material in a portion of the semiconductor; (c) forming a doped region in the semiconductor having a portion thereof contiguous to the isolation region, such doped region being formed with a conductivity type opposite the first conductivity type; (d) bringing an etchant into contact with a surface portion of the doped region and a contiguous surface portion of the isolation region; and (e) selectively etching the doped region forming a depression with converging side wall portions separated from the isolation region by portions of the doped region.
Claim 8
Dependent Claim
13 words
The method recited in claim 5 wherein the etchant is an anisotropic etchant.
Claim 9
Dependent Claim
31 words
The method recited in claim 6 including the step of introducing particles capable of establishing the opposite type conductivity region into the semiconductor body beneath bottom portions of the formed depression.
Claim 10
Dependent Claim
31 words
The method recited in claim 7 wherein the introducing step includes the step of introducing such particles with a predetermined doping concentration less than the doping concentration of the doped region.
Claim 11
Dependent Claim
21 words
The method recited in claim 8 including the step of forming an electrical contact on the bottom portion of the depression.
Claim 12
Independent Claim
95 words
A method for forming a semiconductor structure comprising the steps of: (a) providing an isolation region having an insulating material in a semiconductor body; (b) forming a doped region in such semiconductor body, a portion of such doped region being contiguous to a portion of the isolation region; and (c) forming a depression in the doped region with upper side wall portions in contact with portions of the insulating material and lower side wall portions separated from an adjacent portion of the insulating material of the isolation region by a portion of the doped region.
Claim 13
Independent Claim
95 words
A method for forming a semiconductor structure comprising the steps of: (a) providing an isolation region having an insulating material in a semiconductor body; (b) forming a doped region in such semiconductor body, a portion of such doped region being contiguous to a portion of the isolation region; and (c) forming a depression in the doped region with upper side wall portions in contact with portions of the insulating material and lower side wall portions separated from an adjacent portion of the insulating material of the isolation region by a portion of the doped region.
Claim 14
Dependent Claim
24 words
The method recited in claim 10 including the step of forming an a second doped region on a bottom portion of the formed depression.
Claim 15
Dependent Claim
19 words
The method recited in claim 11 including the step of forming an electrical contact with the second doped region.
Claim 16
Dependent Claim
18 words
The method recited in claim 11 including the step of forming an electrical contact with the semiconductor body.
Claim 17
Dependent Claim
18 words
The method recited in claim 13 including the step of forming an electrical contact with the doped region.
Claim 18
Independent Claim
130 words
A method for forming a semiconductor device comprising the steps of: (a) providing an isolation region having an insulating material in a doped semiconductor body; (b) forming an oppositely doped region in such semiconductor with a portion of such doped region being formed adjacent a portion of the isolation region; (c) forming a depression in the doped region with converging side walls separated from adjacent portions of the isolation region by a portion of the doped region; (d) subsequently forming a second doped region in the semiconductor body beneath bottom portions of the depression, such second doped region being of the same type dopant as the first-mentioned doped region and of lesser doping concentration than such first-mentioned doped region; and (e) providing an electrical contact to the second doped region.
Claim 19
Independent Claim
130 words
A method for forming a semiconductor device comprising the steps of: (a) providing an isolation region having an insulating material in a doped semiconductor body; (b) forming an oppositely doped region in such semiconductor with a portion of such doped region being formed adjacent a portion of the isolation region; (c) forming a depression in the doped region with converging side walls separated from adjacent portions of the isolation region by a portion of the doped region; (d) subsequently forming a second doped region in the semiconductor body beneath bottom portions of the depression, such second doped region being of the same type dopant as the first-mentioned doped region and of lesser doping concentration than such first-mentioned doped region; and (e) providing an electrical contact to the second doped region.
Claim 20
Dependent Claim
19 words
The method recited in claim 15 including the step of providing an electrical contact to the first-mentioned doped region.
Claim 21
Dependent Claim
18 words
The method recited in claim 15 including the step of providing an electrical contact to the semiconductor body.
Claim 22
Independent Claim
160 words
The method of forming a transistor comprising the steps of: (a) forming a doped epitaxial layer on a substrate; (b) forming an isolation region having an insulating material in a portion of the epitaxial layer; (c) forming a first doped region in the epitaxial layer with a conductivity type opposite that of the epitaxial layer, such first doped region having a portion thereof adjacent the isolation region; (d) forming a depression in the doped region having a side wall separated from portions of the isolation region by portions of the first doped region; (e) subsequently forming a second doped region of conductivity type like that of the first doped region in the epitaxial layer beneath a bottom portion of the depression; and (f) forming an emitter contact on the bottom of the depression in contact with the second doped region, a base electrode in contact with the first doped region, and a collector contact in contact with the epitaxial layer.
Claim 23
Independent Claim
160 words
The method of forming a transistor comprising the steps of: (a) forming a doped epitaxial layer on a substrate; (b) forming an isolation region having an insulating material in a portion of the epitaxial layer; (c) forming a first doped region in the epitaxial layer with a conductivity type opposite that of the epitaxial layer, such first doped region having a portion thereof adjacent the isolation region; (d) forming a depression in the doped region having a side wall separated from portions of the isolation region by portions of the first doped region; (e) subsequently forming a second doped region of conductivity type like that of the first doped region in the epitaxial layer beneath a bottom portion of the depression; and (f) forming an emitter contact on the bottom of the depression in contact with the second doped region, a base electrode in contact with the first doped region, and a collector contact in contact with the epitaxial layer.
Claim 24
Independent Claim
99 words
A method for forming a semiconductor structure comprising the steps of: (a) providing a semiconductor; (b) forming a region of a material different from the semiconductor in a portion of the semiconductor, such material extending from a surface portion of the semiconductor to a predetermined depth within the semiconductor; (c) bringing an etchant into contact with a surface portion of the material and a contiguous surface portion of the semiconductor selectively etching the semiconductor forming a depression in such semiconductor having side wall portions separated from portions of the material extending into the semiconductor by portions of the semiconductor.
Claim 25
Independent Claim
99 words
A method for forming a semiconductor structure comprising the steps of: (a) providing a semiconductor; (b) forming a region of a material different from the semiconductor in a portion of the semiconductor, such material extending from a surface portion of the semiconductor to a predetermined depth within the semiconductor; (c) bringing an etchant into contact with a surface portion of the material and a contiguous surface portion of the semiconductor selectively etching the semiconductor forming a depression in such semiconductor having side wall portions separated from portions of the material extending into the semiconductor by portions of the semiconductor.
Claim 26
Independent Claim
96 words
A method for forming a semiconductor structure comprising the steps of: (a) forming an isolation region having an insulating material in a portion of a semiconductor, such material extending from a surface portion of the semiconductor to a predetermined depth within the semiconductor; and (b) bringing an etchant into contact with a surface portion of the insulating material and a contiguous surface portion of the semiconductor selectively etching the semiconductor forming a depression in the semiconductor having side wall portions separated from portions of the insulating material extending into the semiconductor by portions of such semiconductor.
Claim 27
Independent Claim
96 words
A method for forming a semiconductor structure comprising the steps of: (a) forming an isolation region having an insulating material in a portion of a semiconductor, such material extending from a surface portion of the semiconductor to a predetermined depth within the semiconductor; and (b) bringing an etchant into contact with a surface portion of the insulating material and a contiguous surface portion of the semiconductor selectively etching the semiconductor forming a depression in the semiconductor having side wall portions separated from portions of the insulating material extending into the semiconductor by portions of such semiconductor.
Claim 28
Dependent Claim
13 words
The method recited in claim 19 wherein the etchant is an isotropic etchant.
Claim 29
Independent Claim
91 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a doped region in a semiconductor contiguous to an isolation region having an insulating material extending from a surface portion of the semiconductor into such semiconductor; and (b) bringing an etchant into contact with a surface portion of the doped region and a contiguous surface portion of the insulating material selectively etching the semiconductor forming a depression in such doped region with side wall portions separated from portions of the insulating material by portions of the doped region.
Claim 30
Independent Claim
91 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a doped region in a semiconductor contiguous to an isolation region having an insulating material extending from a surface portion of the semiconductor into such semiconductor; and (b) bringing an etchant into contact with a surface portion of the doped region and a contiguous surface portion of the insulating material selectively etching the semiconductor forming a depression in such doped region with side wall portions separated from portions of the insulating material by portions of the doped region.
Claim 31
Independent Claim
79 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a doped region in a semiconductor contiguous to an isolation region having an insulating material extending from a surface portion of the semiconductor into such semiconductor; and (b) forming a depression in the doped region with upper side wall portions in contact with portions of the insulating material and lower side wall portions separated from portions of the insulating material by portions of the doped region.
Claim 32
Independent Claim
79 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a doped region in a semiconductor contiguous to an isolation region having an insulating material extending from a surface portion of the semiconductor into such semiconductor; and (b) forming a depression in the doped region with upper side wall portions in contact with portions of the insulating material and lower side wall portions separated from portions of the insulating material by portions of the doped region.
Claim 33
Independent Claim
81 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a doped region in a portion of a semiconductor having a first doping concentration; (b) forming a depression in the semiconductor with side wall portions passing through the doped region into the semiconductor and a bottom wall portion disposed in the semiconductor; (c) subsequently forming a second doped region in the bottom wall portion, such second doped region having a doping concentration less than the first doping concentration.
Claim 34
Independent Claim
81 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a doped region in a portion of a semiconductor having a first doping concentration; (b) forming a depression in the semiconductor with side wall portions passing through the doped region into the semiconductor and a bottom wall portion disposed in the semiconductor; (c) subsequently forming a second doped region in the bottom wall portion, such second doped region having a doping concentration less than the first doping concentration.
Claim 35
Independent Claim
99 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a first doped region in a portion of a semiconductor, such first doped region having a first doping concentration; (b) forming a depression in the semiconductor with side wall portions passing through the first doped region into the semiconductor and a bottom wall portion disposed in the semiconductor; (c) subsequently forming a second doped region under the bottom wall portions of the depression and joining edge portions of the second doped region and the first doped region to electrically connect such first and second doped regions.
Claim 36
Independent Claim
99 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a first doped region in a portion of a semiconductor, such first doped region having a first doping concentration; (b) forming a depression in the semiconductor with side wall portions passing through the first doped region into the semiconductor and a bottom wall portion disposed in the semiconductor; (c) subsequently forming a second doped region under the bottom wall portions of the depression and joining edge portions of the second doped region and the first doped region to electrically connect such first and second doped regions.
Claim 37
Independent Claim
141 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a first doped region in a portion of a semiconductor, such first doped region having a first doping concentration; (b) forming a depression in the semiconductor with side wall portions passing through the first doped region into the semiconductor and a bottom wall portion disposed in the semiconductor; (c) increasing the size of the first doped region so that edge portions of such region extend under the bottom wall portion of the depression; and (d) forming a second doped region in the semiconductor under the bottom wall portion of the depression, end portions of such doped region extending into the edge portions of first doped region electrically connecting the first and second doped regions, such second doped region having a doping concentration less than the first doping concentration.
Claim 38
Independent Claim
141 words
A method for forming a semiconductor structure comprising the steps of: (a) forming a first doped region in a portion of a semiconductor, such first doped region having a first doping concentration; (b) forming a depression in the semiconductor with side wall portions passing through the first doped region into the semiconductor and a bottom wall portion disposed in the semiconductor; (c) increasing the size of the first doped region so that edge portions of such region extend under the bottom wall portion of the depression; and (d) forming a second doped region in the semiconductor under the bottom wall portion of the depression, end portions of such doped region extending into the edge portions of first doped region electrically connecting the first and second doped regions, such second doped region having a doping concentration less than the first doping concentration.
References Cited (Backward Citations)
US3083441A
Cited
US3755001A
Cited
US3648125A
Cited
US3783047A
Cited
US4110779A
Cited
US4066473A
Cited
US4115797A
Cited
US4155783A
Cited
US4168999A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-14 | 1985-03-16 | 1985-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-14 | 1989-03-16 | 1989-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-14 | 1993-03-16 | 1993-09-15 | $7700.00 | Window Closed / Lapsed |