US4648174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making high breakdown voltage semiconductor device
Assignee: Fairchild Semiconductor Corp
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Filing: 1985-02-05
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Granted: 1987-03-10
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Expires: 2005-02-05
Abstract
Abstract A multiple-zone junction termination extension region is formed adjacent a reverse-blocking junction in a semiconductor device to increase the breakdown voltage of such device. A single mask is used to form the multiple-zone JTE region, with the mask having different patterns of openings in the different zones of the mask. Adjacent openings are maintained with a center-to-center spacing of less than 25 percent of the depletion width of the reverse-blocking junction in a voltage-supporting semiconductor layer adjoining the reverse-blocking junction at the ideal breakdown voltage of the junction. As a consequence, the resulting non-uniformities in doping of the various zones of the JTE region are negligibly small. An alternative JTE region is finely-graduated in dopant level from one end of the region to the other, as opposed to having multiple zones of discrete doping levels.
Inventors
- 👤 Victor A. K. Temple
- 👤 Wirojana Tantraporn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:31
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/40; H10P76/408; H10D; H10D62/00; H10D62/10; H10D62/102; H10D62/103; H10D62/105; H10D62/124; H10D62/125; Y; Y10; Y10S; Y10S148/00; Y10S148/106; Y10S148/145
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
315 words
In a process of fabricating a semiconductor device including, when complete, at least one reverse-blocking junction, a voltage-supporting region of one conductivity type having an upper surface and forming one side of said junction; and wherein said reverse-blocking junction includes a terminated portion at said upper surface of said voltage-supporting region, and said voltage-supporting region at a location beneath said reverse-blocking junction contains a depletion region width W D when said junction is reverse-biased to its ideal breakdown voltage, the improvement comprising, in combination with the foregoing: (a) forming a single mask of not so uniform thickness on said semiconductor device adjacent said terminated portion to be used in forming a junction termination extension region, said step of forming a single mask comprising configuring said mask to expose a percentage x of a first portion of said voltage-supporting region adjacent said terminated portion and to expose a percentage y of a second portion of said voltage-supporting region adjacent said first portion remote from said terminated portion of said reverse-blocking junction, and wherein x is greater than y and adjacent openings in said mask have a center-to-center spacing of less than 0.25 W D ; and (b) simultaneously doping said first and second portions of said voltage supporting region through said mask with the same concentration of dopant to form in said voltage support region, a first region contiguous with said terminated portion and a second region adjacent said first region, said first and second regions being of approximately the same depth and establishing a junction termination extension wherein the lowermost extent of said junction termination extension is at or below the lowermost extent of said reverse-blocking junction relative to said upper surface of said voltage-supporting layer and each of said first and second regions having a lower dopant dosage per unit volume than any adjacent region more proximate to said terminated portion of said junction.
Claim 2
Dependent Claim
315 words
In a process of fabricating a semiconductor device including, when complete, at least one reverse-blocking junction, a voltage-supporting region of one conductivity type having an upper surface and forming one side of said junction; and wherein said reverse-blocking junction includes a terminated portion at said upper surface of said voltage-supporting region, and said voltage-supporting region at a location beneath said reverse-blocking junction contains a depletion region width W D when said junction is reverse-biased to its ideal breakdown voltage, the improvement comprising, in combination with the foregoing: (a) forming a single mask of not so uniform thickness on said semiconductor device adjacent said terminated portion to be used in forming a junction termination extension region, said step of forming a single mask comprising configuring said mask to expose a percentage x of a first portion of said voltage-supporting region adjacent said terminated portion and to expose a percentage y of a second portion of said voltage-supporting region adjacent said first portion remote from said terminated portion of said reverse-blocking junction, and wherein x is greater than y and adjacent openings in said mask have a center-to-center spacing of less than 0.25 W D ; and (b) simultaneously doping said first and second portions of said voltage supporting region through said mask with the same concentration of dopant to form in said voltage support region, a first region contiguous with said terminated portion and a second region adjacent said first region, said first and second regions being of approximately the same depth and establishing a junction termination extension wherein the lowermost extent of said junction termination extension is at or below the lowermost extent of said reverse-blocking junction relative to said upper surface of said voltage-supporting layer and each of said first and second regions having a lower dopant dosage per unit volume than any adjacent region more proximate to said terminated portion of said junction.
Claim 3
Dependent Claim
40 words
The invention of claim 1, wherein the step of simultaneously doping said first and second portion of said voltage-supporting region through said mask comprises introducing dopant of the opposite conductivity type into said voltage-supporting region through openings in said mask.
Claim 4
Dependent Claim
28 words
The invention of claim 1, wherein the mask formation step comprises configuring said mask to have adjacent openings with center-to-center spacings of less than 0.1 W D .
Claim 5
Dependent Claim
55 words
The invention of claim 1 wherein said mask formation step further comprises configuring said mask to expose a percentage z of a third portion of said voltage-supporting region, said third portion being adjacent said second portion and more remote from said terminated portion and x is greater than y and y is greater than z.
Claim 6
Dependent Claim
80 words
The invention of claim 4, wherein said mask formation step further comprises configuring said mask to expose a percentage A' of a fourth portion of said voltage supporting region adjacent said third portion wherein x y z A', said first, second, third, and fourth regions of said voltage-supporting region underlying respective portions exposed by said mask each region receiving a lower dopant dosage per unit device area than any adjacent region more proximate to said terminated portion of said junction.
Claim 7
Dependent Claim
41 words
The invention of claim 5, wherein the zone most proximate to said terminated portion of said reverse-blocking junction has a dimension in a direction extending away from said junction in the range of 0.05 W D to 0.5 W D .
Claim 8
Dependent Claim
40 words
The invention of claim 6, wherein the zone most distant from said terminated portion of said reverse-blocking junction has a dimension in a direction extending away from said junction in the range 0.05 W D to 0.5 W D .
Claim 9
Dependent Claim
33 words
The method of claim 5, wherein said percentage x is approximately 100 percent, said percentage y is approximately 65 percent, said percentage z is approximately 50% and said percentage A' is approximately 25%.
Claim 10
Dependent Claim
13 words
The invention of claim 1, wherein said voltage-blocking junction comprises a P-N junction.
Claim 11
Dependent Claim
15 words
The invention of claim 1, wherein said reverse-blocking junction comprises a Schottky barrier rectifying junction.
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) | 1990-03-09 | 1990-09-08 | 1991-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-09 | 1994-09-08 | 1995-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-09 | 1998-09-08 | 1999-03-10 | $7700.00 | Window Closed / Lapsed |