US5670392A
Expired / Lapsed
US
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Process for manufacturing high-density MOS-technology power devices
Assignee: STMicroelectronics SRL
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Filing: 1995-06-30
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Granted: 1997-09-23
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Expires: 2015-06-30
Abstract
Abstract A process for manufacturing high-density MOS-technology power devices includes the steps of: forming a conductive insulated gate layer on a surface of a lightly doped semiconductor material layer of a first conductivity type; forming an insulating material layer over the insulated gate layer; selectively removing the insulating material layer and the underlying insulated gate layer to form a plurality of elongated windows having two elongated edges and two short edges, delimiting respective uncovered surface stripes of the semiconductor material layer; implanting a high dose of a first dopant of the first conductivity type along two directions which lie in a plane transversal to said elongated windows and orthogonal to the semiconductor material layer surface, and which are substantially symmetrically tilted at a first prescribed angle with respect to a direction orthogonal to the semiconductor material layer surface, the first angle depending on the overall thickness of the insulated gate layer and of the insulating material layer to prevent the first dopant from being implanted in a central stripe of the uncovered surface stripes, to form pairs of heavily doped elongated source regions of the first conductivity type which extend along the two elongated edges of each elongated window and which are separated by the central stripe; implanting a low dose of a second dopant of a second conductivity type along two directions which lie in the plane, and which are substantially symmetrically tilted of a second prescribed angle with respect to the orthogonal direction, to form doped regions of the second conductivity type each comprising two lightly doped elongated channel regions extending under the two elongated edges of each elongated window; implanting a high dose of a third dopant of the second conductivity type substantially along the orthogonal direction, the insulating material layer acting as a mask, to form heavily doped regions substantially aligned with the edges of the elongated windows.
Inventors
- 👤 Giuseppe Ferla
- 👤 Ferruccio Frisina
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:44
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/028; H10D30/0291; H10D30/0293; H10D62/00; H10D62/10; H10D62/124; H10D62/126; H10D62/127; H10D62/17; H10D62/393; H10P; H10P30/00; H10P30/20; H10P30/22; H10P30/221; H10P30/222; Y; Y10; Y10S; Y10S148/00; Y10S148/126
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
334 words
A process for manufacturing high-density MOS-technology power devices, comprising the steps of: a) forming a conductive insulated gate layer on a surface of a lightly doped semiconductor material layer of a first conductivity type; b) forming an insulating material layer over the insulated gate; c) moving the insulating material layer and the underlying insulated gate layer to form a plurality of elongated windows each having two elongated edges and two short edges, delimiting respective uncovered surface stripes of the semiconductor material layer; d) implanting a high dose of a first dopant of the first conductivity type along first and second directions which lie in a plane transverse to said elongated windows and orthogonal to the semiconductor material layer surface, the first and second directions substantially symmetrical to one another at a first prescribed angle with respect to a direction orthogonal to the semiconductor material layer surface, the first prescribed angle depending on an overall thickness of the insulated gate layer and of the insulating material layer to prevent the first dopant from being implanted in a central stripe of said uncovered surface stripes, to form first and second heavily doped elongated source regions of the first conductivity type which extend along said two elongated edges of each elongated window, respectively, and which are separated by said central stripe; e) implanting a low dose of a second dopant of a second conductivity type along third and fourth directions which lie in said transverse plane, the third and fourth directions substantially symmetrical to one another at a second prescribed angle with respect to said orthogonal direction, to form third and fourth lightly doped elongated channel regions of the second conductivity type extending, respectively, under the two elongated edges of each elongated window; and f) implanting a high dose of a third dopant of the second conductivity type substantially along said orthogonal direction, the insulating material layer acting as a mask, to form heavily doped regions substantially aligned with the edges of each of the elongated windows.
Claim 2
Dependent Claim
334 words
A process for manufacturing high-density MOS-technology power devices, comprising the steps of: a) forming a conductive insulated gate layer on a surface of a lightly doped semiconductor material layer of a first conductivity type; b) forming an insulating material layer over the insulated gate; c) moving the insulating material layer and the underlying insulated gate layer to form a plurality of elongated windows each having two elongated edges and two short edges, delimiting respective uncovered surface stripes of the semiconductor material layer; d) implanting a high dose of a first dopant of the first conductivity type along first and second directions which lie in a plane transverse to said elongated windows and orthogonal to the semiconductor material layer surface, the first and second directions substantially symmetrical to one another at a first prescribed angle with respect to a direction orthogonal to the semiconductor material layer surface, the first prescribed angle depending on an overall thickness of the insulated gate layer and of the insulating material layer to prevent the first dopant from being implanted in a central stripe of said uncovered surface stripes, to form first and second heavily doped elongated source regions of the first conductivity type which extend along said two elongated edges of each elongated window, respectively, and which are separated by said central stripe; e) implanting a low dose of a second dopant of a second conductivity type along third and fourth directions which lie in said transverse plane, the third and fourth directions substantially symmetrical to one another at a second prescribed angle with respect to said orthogonal direction, to form third and fourth lightly doped elongated channel regions of the second conductivity type extending, respectively, under the two elongated edges of each elongated window; and f) implanting a high dose of a third dopant of the second conductivity type substantially along said orthogonal direction, the insulating material layer acting as a mask, to form heavily doped regions substantially aligned with the edges of each of the elongated windows.
Claim 3
Dependent Claim
26 words
The process according to claim 1, wherein the implantation of said first dopant is prevented in center regions of the short edges of said elongated windows.
Claim 4
Dependent Claim
36 words
The process according to claim 1, further comprising the steps of: g) forming insulating material sidewalk spacers at the edges of said elongated windows; and h) forming a conductive material layer over the insulating material layer.
Claim 5
Dependent Claim
17 words
The process according to claim 1, wherein said first prescribed angle is in a range of 45°-60°.
Claim 6
Dependent Claim
17 words
The process according to claim 1, wherein said second prescribed angle is in a range of 35°-60°.
Claim 7
Dependent Claim
32 words
The process according to claim 1, wherein said third dopant is implanted at an energy sufficiently high so that a peak concentration of the third dopant is located under the source regions.
Claim 8
Dependent Claim
20 words
The process according to claim 6, wherein said third dopant is implanted at an energy of at least 100 KeV.
Claim 9
Dependent Claim
16 words
The process according to claim 1, wherein the step e) is performed before the step d).
Claim 10
Dependent Claim
21 words
The process according to claim 8, wherein the step f) is performed after the step e) and before the step d).
Claim 11
Dependent Claim
16 words
The process according to claim 1, wherein the step f) is performed before the step d).
Claim 12
Dependent Claim
21 words
The process according to claim 10, wherein the step e) is performed after the step f) and before the step d).
Claim 13
Dependent Claim
16 words
The process according to claim 1, wherein the step f) is performed before the step e).
Claim 14
Dependent Claim
39 words
The process according to claim 1, wherein said insulated gate layer is formed by growing a thin oxide layer over the surface of the semiconductor material layer, and covering the thin oxide layer with a further conductive material layer.
Claim 15
Dependent Claim
23 words
The process according to claim 1, wherein said semiconductor material layer is an epitaxial layer grown over a heavily doped semiconductor material substrate.
Claim 16
Dependent Claim
25 words
The process according to claim 14, wherein said semiconductor material substrate is doped of the first conductivity type, the power device being a power MOSFET.
Claim 17
Dependent Claim
24 words
The process according to claim 14, wherein said semiconductor material substrate is doped of the second conductivity type, the power device being an IGBT.
Claim 18
Dependent Claim
22 words
The process according to claim 1, wherein said first conductivity type is N type, and said second conductivity type is P type.
Claim 19
Dependent Claim
22 words
The process according to claim 1, wherein said first conductivity type is P type, and said second conductivity type is N type.
Claim 20
Dependent Claim
330 words
A process for manufacturing a high-density MOS-technology power device, the power device including a conductive insulated gate layer on a surface of a lightly doped semiconductor material layer of a first conductivity type, an insulating material layer over the insulated gate layer, and the insulating material layer and the underlying insulated gate layer forming an elongated window having two elongated edges and two short edges delimiting an uncovered surface stripe of the semiconductor material layer, the process comprising the steps of: a) implanting a high dose of a first dopant of the first conductivity type along first and second directions which lie in a plane transverse to said elongated window and orthogonal to the semiconductor material layer surface, the first and second directions substantially symmetrical to one another at a first prescribed angle with respect to a direction orthogonal to the semiconductor material layer surface, the first prescribed angle depending on an overall thickness of the insulated gate layer and of the insulating material layer to prevent the tint dopant from being implanted in a central stripe of said uncovered surface stripe, to form first and second heavily doped elongated source regions of the first conductivity type which extend along said two elongated edges of the elongated window and which are separated by said central stripe; b) implanting a low dose of a second dopant of a second conductivity type along third and fourth directions which lie in said transverse plane, the third and fourth directions substantially symmetrical to one another at a second prescribed angle with respect to said orthogonal direction, to form third and fourth lightly doped elongated channel regions of the second conductivity type extending, respectively, under the two elongated edges of the elongated window; and c) implanting a high dose of a third dopant of the second conductivity type substantially along said orthogonal direction, the insulating material layer acting as a mask, to form heavily doped regions substantially aligned with the edges of the elongated window.
Claim 21
Dependent Claim
330 words
A process for manufacturing a high-density MOS-technology power device, the power device including a conductive insulated gate layer on a surface of a lightly doped semiconductor material layer of a first conductivity type, an insulating material layer over the insulated gate layer, and the insulating material layer and the underlying insulated gate layer forming an elongated window having two elongated edges and two short edges delimiting an uncovered surface stripe of the semiconductor material layer, the process comprising the steps of: a) implanting a high dose of a first dopant of the first conductivity type along first and second directions which lie in a plane transverse to said elongated window and orthogonal to the semiconductor material layer surface, the first and second directions substantially symmetrical to one another at a first prescribed angle with respect to a direction orthogonal to the semiconductor material layer surface, the first prescribed angle depending on an overall thickness of the insulated gate layer and of the insulating material layer to prevent the tint dopant from being implanted in a central stripe of said uncovered surface stripe, to form first and second heavily doped elongated source regions of the first conductivity type which extend along said two elongated edges of the elongated window and which are separated by said central stripe; b) implanting a low dose of a second dopant of a second conductivity type along third and fourth directions which lie in said transverse plane, the third and fourth directions substantially symmetrical to one another at a second prescribed angle with respect to said orthogonal direction, to form third and fourth lightly doped elongated channel regions of the second conductivity type extending, respectively, under the two elongated edges of the elongated window; and c) implanting a high dose of a third dopant of the second conductivity type substantially along said orthogonal direction, the insulating material layer acting as a mask, to form heavily doped regions substantially aligned with the edges of the elongated window.
Claim 22
Dependent Claim
32 words
The process as recited in claim 19, wherein the implanting of the first dopant of the first conductivity type is prevented in center regions of the short edges of the elongated window.
Claim 23
Dependent Claim
25 words
The process as recited in claim 19, further comprising the step of forming an insulating material sidewall spacer at an edge of the elongated window.
Claim 24
Dependent Claim
18 words
The process as recited in claim 19, wherein the first prescribed angle is in a range of 45°-60°.
Claim 25
Dependent Claim
18 words
The process as recited in claim 19, wherein the second prescribed angle is in a range of 35°-60°.
Claim 26
Dependent Claim
37 words
The process as recited in claim 19, wherein the third dopant is implanted with an implantation energy level sufficient such that a peak concentration of the third dopant is located under the first and second source regions.
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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) | 2000-09-22 | 2001-03-24 | 2001-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-22 | 2005-03-24 | 2005-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-22 | 2009-03-24 | 2009-09-23 | $7700.00 | Window Closed / Lapsed |