US5213994A
Expired / Lapsed
US
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Method of making high voltage semiconductor device
Assignee: Motorola Solutions Inc
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Filing: 1990-09-17
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Granted: 1993-05-25
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Expires: 2010-09-17
Abstract
Abstract An improved method and structure for high voltage semiconductor devices capable of blocking voltages of the order of 1000 volts and greater is described. In a preferred embodiment, a blanket P layer is formed in an N - epi-layer on an N + substrate. An annular groove is etched through the blanket P layer into the N - epi-layer. The bottom of the groove is doped N + using the same mask as for the first groove etch. A second groove is formed inside of and partly overlapping the first groove and extending to a greater depth than the first groove, but not through the epi-layer. The second groove is filled with passivating material, metal electrodes are applied to the P + region and the N + substrate, and the devices separated at the N + region lying outside the second groove in the bottom of the first groove. Excellent high voltage blocking characteristics are obtained with the same or fewer process steps and better yield.
Inventors
- 👤 Earl D. Fuchs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:02
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/102; H10D62/103; H10D62/104; H10D8/00; H10D8/50
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
189 words
A method for forming a high voltage semiconductor device comprising: providing a substrate having a conductive first doped region of a first thickness adjacent a first surface thereof; forming a first depression extending from the first surface through the first doped region; forming a conductive second doped region at least on a bottom part of the first depression; forming a second depression not entirely co-extensive with the first depression and having at least a first part overlapping a portion of the first depression and extending into the substrate from the first surface through the portion of the first depression; wherein the steps of forming the first and second depressions comprise forming annular first and second depressions, each having an inner and outer perimeter wherein the first part of the second depression has a smaller outer perimeter than the outer perimeter of the first depression; and wherein the step of forming a second depression having at least a first part further comprises forming a second part of the second depression spaced apart from the first part and having an inner perimeter greater than the outer perimeter of the second depression.
Claim 2
Independent Claim
189 words
A method for forming a high voltage semiconductor device comprising: providing a substrate having a conductive first doped region of a first thickness adjacent a first surface thereof; forming a first depression extending from the first surface through the first doped region; forming a conductive second doped region at least on a bottom part of the first depression; forming a second depression not entirely co-extensive with the first depression and having at least a first part overlapping a portion of the first depression and extending into the substrate from the first surface through the portion of the first depression; wherein the steps of forming the first and second depressions comprise forming annular first and second depressions, each having an inner and outer perimeter wherein the first part of the second depression has a smaller outer perimeter than the outer perimeter of the first depression; and wherein the step of forming a second depression having at least a first part further comprises forming a second part of the second depression spaced apart from the first part and having an inner perimeter greater than the outer perimeter of the second depression.
Claim 3
Dependent Claim
38 words
The method of claim 1 wherein the step of forming the second part of the second depression comprises forming the second part of the second depression with the same depth as the first part of the second depression.
Claim 4
Dependent Claim
41 words
The method of claim 1 wherein the steps of forming the first and second parts of the second depression comprise forming spaced-apart first and second parts of the second depression separated by a portion of the bottom of the first depression.
Claim 5
Dependent Claim
139 words
A process for forming a high voltage semiconductor device, comprising: providing a semiconductor substrate having a first conductivity type and first conductivity and having a first principal surface; providing a first region of an opposite second conductivity type and a second conductivity extending to a first surface of the substrate and forming a PN junction with the substrate at a first depth below the first surface; forming a first annular recess extending into the substrate from the first surface to a second depth greater than the first depth; providing a second region of the first conductivity type and a third conductivity including the bottom of the first annular recess; and forming a second annular recess extending from the first surface into the substrate to a third depth greater than the second depth and partially overlapping the first annular recess.
Claim 6
Dependent Claim
139 words
A process for forming a high voltage semiconductor device, comprising: providing a semiconductor substrate having a first conductivity type and first conductivity and having a first principal surface; providing a first region of an opposite second conductivity type and a second conductivity extending to a first surface of the substrate and forming a PN junction with the substrate at a first depth below the first surface; forming a first annular recess extending into the substrate from the first surface to a second depth greater than the first depth; providing a second region of the first conductivity type and a third conductivity including the bottom of the first annular recess; and forming a second annular recess extending from the first surface into the substrate to a third depth greater than the second depth and partially overlapping the first annular recess.
Claim 7
Dependent Claim
17 words
The process of claim 4 wherein the second and third conductivities are greater than the first conductivity.
Claim 8
Dependent Claim
26 words
The process of claim 4 wherein the step of providing the second region comprises providing the second region having a thickness less than the first depth.
Claim 9
Dependent Claim
37 words
The process of claim 6 wherein the step of forming the second annular recess comprises forming the second recess to a depth sufficient to extend through the second region where the second recess overlaps the first recess.
Claim 10
Dependent Claim
16 words
The process of claim 4 further comprising, substantially filling the second recess with a passivating material.
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) | 1996-05-24 | 1996-11-23 | 1997-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-24 | 2000-11-23 | 2001-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-24 | 2004-11-23 | 2005-05-25 | $7700.00 | Window Closed / Lapsed |