Patent US2130124A successfully refreshed from Google Patents.
US4960731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a power diode with high reverse voltage rating
Assignee: Robert Bosch GmbH
•
Filing: 1989-04-27
•
Granted: 1990-10-02
•
Expires: 2009-04-27
Abstract
Abstract In making a power diode with high reverse voltage rating, corrosion of the silicon wafer surface by gettering substances is avoided by employing two different diffusion steps. In the first step, boron and phosphorus are respectively applied to opposing major surfaces of the disk-shaped semiconductor body (10) and driven into it by heating to a predetermined temperature. Gettering is employed to increase the charge carrier lifetime and thereby reduce the forward voltage drop of the diode. The gettering is carried out in a second diffusion step at a diffusion temperature sufficiently reduced with respect to the diffusion temperature of the first step to avoid significantly affecting the depth of diffusion of the doping substances into the semiconductor body.
Inventors
- 👤 Richard Spitz
- 👤 Vesna Biallas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:14
CPC Classifications
H; H10; H10D; H10D8/00; H10D8/01; H10D8/045; H10D8/422; H10P; H10P36/00; H10P36/20; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/92
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
142 words
Method of making a high-reverse-voltage-rated power diode from a disk-shaped monocrystalline semiconductor body (10) having two major surfaces, onto each of which is applied respectively as a doping substance one of boron and phosphorus, after which, in a first diffusion step, said doping substances are driven into said semiconductor body (10) to a predetermined diffusion depth by heating said semiconductor body to a predetermined temperature, wherein, to lower the forward voltage drop of the diode, the lifetime of the charge carriers is increased by gettering, said gettering being carried out in a first diffusion step and a second diffusion step following said first diffusion step; said second diffusion step being carried out at a temperature sufficiently reduced, with respect to the temperature of said first diffusion step, to avoid significantly influencing depth of diffusion of said doping substances into said semiconductor body.
Claim 2
Dependent Claim
142 words
Method of making a high-reverse-voltage-rated power diode from a disk-shaped monocrystalline semiconductor body (10) having two major surfaces, onto each of which is applied respectively as a doping substance one of boron and phosphorus, after which, in a first diffusion step, said doping substances are driven into said semiconductor body (10) to a predetermined diffusion depth by heating said semiconductor body to a predetermined temperature, wherein, to lower the forward voltage drop of the diode, the lifetime of the charge carriers is increased by gettering, said gettering being carried out in a first diffusion step and a second diffusion step following said first diffusion step; said second diffusion step being carried out at a temperature sufficiently reduced, with respect to the temperature of said first diffusion step, to avoid significantly influencing depth of diffusion of said doping substances into said semiconductor body.
Claim 3
Dependent Claim
24 words
Method according to claim 1, wherein said second diffusion step is carried out at a temperature between about 1050° C. and about 1150° C.
Claim 4
Dependent Claim
20 words
Method according to claim 2, wherein said second diffusion step is carried out at a temperature of about 1100° C.
Claim 5
Dependent Claim
20 words
Method according to claim 3, wherein said second diffusion step is carried out over a period of about 30 hours.
Claim 6
Dependent Claim
28 words
Method according to claim 1, wherein said first diffusion step is carried out at a temperature of about 1265° C. and over a period of about 30 hours.
Claim 7
Dependent Claim
28 words
Method according to claim 2, wherein said first diffusion step is carried out at a temperature of about 1265° C. and over a period of about 30 hours.
Claim 8
Dependent Claim
28 words
Method according to claim 3, wherein said first diffusion step is carried out at a temperature of about 1265° C. and over a period of about 30 hours.
Claim 9
Dependent Claim
28 words
Method according to claim 4, wherein said first diffusion step is carried out at a temperature of about 1265° C. and over a period of about 30 hours.
Claim 10
Dependent Claim
19 words
Method according to claim 1, wherein said first and second diffusion steps are carried out in an oxidizing atmosphere.
Claim 11
Dependent Claim
19 words
Method according to claim 2, wherein said first and second diffusion steps are carried out in an oxidizing atmosphere.
Claim 12
Dependent Claim
19 words
Method according to claim 3, wherein said first and second diffusion steps are carried out in an oxidizing atmosphere.
Claim 13
Dependent Claim
19 words
Method according to claim 4, wherein said first and second diffusion steps are carried out in an oxidizing atmosphere.
Claim 14
Dependent Claim
19 words
Method according to claim 5, wherein said first and second diffusion steps are carried out in an oxidizing atmosphere.
Claim 15
Dependent Claim
19 words
Method according to claim 6, wherein said first and second diffusion steps are carried out in an oxidizing atmosphere.
Claim 16
Dependent Claim
19 words
Method according to claim 7, wherein said first and second diffusion steps are carried out in an oxidizing atmosphere.
Claim 17
Dependent Claim
19 words
Method according to claim 8, wherein said first and second diffusion steps are carried out in an oxidizing atmosphere.
References Cited (Backward Citations)
US2804405A
Cited
US2802760A
Cited
US3814639A
Cited
US3867203A
Cited
US3914138A
Cited
US4415916A
Cited
US4376657A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-10-01 | 1994-04-02 | 1994-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-01 | 1998-04-02 | 1998-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-01 | 2002-04-02 | 2002-10-02 | $7700.00 | Window Closed / Lapsed |