US3890178A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a semiconductor device having a multi-thickness region
Assignee: US Philips Corp
•
Filing: 1974-01-24
•
Granted: 1975-06-17
•
Expires: 1994-01-24
Abstract
Abstract A semiconductor device comprising at least a first surface region and a second region that are separated by a junction having opposite conductivities, the first region being disposed over the second region and including a central zone and an annular peripheral zone having a thickness less than one-third that of the central zone. The peripheral zone separates the central zone from the boundary of the junction and exhibits high electrical resistance. Also, a method of producing such a semiconductor device.
Inventors
- 👤 Jacques Lebailly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:45
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D99/00; H10H; H10H20/00; H10H20/80; H10P; H10P95/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
184 words
A METHOD OF MANUFACTURING A SEMICONDUCTOR DEVICE COMPRISING AT LEAST TWO REGIONS OF OPPOSITE CONDUCTIVITY TYPES WHICH ARE SEPARATED BY A PLANE JUNCTION AND FURTHER COMPRISING AN ANNULAR PERIPHERAL ZONE OF RELATIVELY HIGH ELECTRICAL RESISTANCE THAT SEPARATES ONE OF THE REGIONS FROM THE BOUNDARY OF THE JUNCTION, SAID METHOD COMPRISING THE STEPS OF DIFFUSING IMPURITIES FROM AT LEAST A PART OF ONE OF THE LARGE FACES OF THE SEMICONDUCTOR CRYSTAL TO PRODUCE SAID FIRST SURFACE REGION THAT HAS A DOPING IMPURITY CONCENTRATION GRADIENT THAT DECLINES WITH THE DEPTH FROM SAID ONE FACE REMOVING LOCALY MATERIAL FROM AT LEAST SAID FIRST REGION AT THE DIFFUSION FACE OF SAID SEMICONDUCTOR CRYSTAL, SAID MATERIAL BEING REMOVED OVER A RESTRICTED PART OF SAID DIFFUSION FACE TO A DEPTH WHICH IS AT LEAST TWO THIRDS OF THE DISTANCE OF SAID JUNCTION FROM SAID SURFACE BUT LESS THAN THEENTIRE SAID DISTANCE, SAID RESTRICTED PART HAVING AN ANNULAR CONFIGURATION AND COMPRISING A BOUNDARY OF SAID JUNCTION, THE DISTANCE BETWEEN THE INNER LIMIT OF SAID RESTRICTED PART AND THE BOUNDARY OF SAID JUNCTION BEING EVERYWHERE AT LEAST EQUAL TO THE DIFFUSION DEPTH.
Claim 2
Independent Claim
184 words
A METHOD OF MANUFACTURING A SEMICONDUCTOR DEVICE COMPRISING AT LEAST TWO REGIONS OF OPPOSITE CONDUCTIVITY TYPES WHICH ARE SEPARATED BY A PLANE JUNCTION AND FURTHER COMPRISING AN ANNULAR PERIPHERAL ZONE OF RELATIVELY HIGH ELECTRICAL RESISTANCE THAT SEPARATES ONE OF THE REGIONS FROM THE BOUNDARY OF THE JUNCTION, SAID METHOD COMPRISING THE STEPS OF DIFFUSING IMPURITIES FROM AT LEAST A PART OF ONE OF THE LARGE FACES OF THE SEMICONDUCTOR CRYSTAL TO PRODUCE SAID FIRST SURFACE REGION THAT HAS A DOPING IMPURITY CONCENTRATION GRADIENT THAT DECLINES WITH THE DEPTH FROM SAID ONE FACE REMOVING LOCALY MATERIAL FROM AT LEAST SAID FIRST REGION AT THE DIFFUSION FACE OF SAID SEMICONDUCTOR CRYSTAL, SAID MATERIAL BEING REMOVED OVER A RESTRICTED PART OF SAID DIFFUSION FACE TO A DEPTH WHICH IS AT LEAST TWO THIRDS OF THE DISTANCE OF SAID JUNCTION FROM SAID SURFACE BUT LESS THAN THEENTIRE SAID DISTANCE, SAID RESTRICTED PART HAVING AN ANNULAR CONFIGURATION AND COMPRISING A BOUNDARY OF SAID JUNCTION, THE DISTANCE BETWEEN THE INNER LIMIT OF SAID RESTRICTED PART AND THE BOUNDARY OF SAID JUNCTION BEING EVERYWHERE AT LEAST EQUAL TO THE DIFFUSION DEPTH.
Claim 3
Dependent Claim
35 words
A method as recited in claim 1, wherein the step of removing said material comprises chemically etching, the surface of the central zone of the surface region being protected against etching by a masking coating.
Claim 4
Dependent Claim
19 words
A method as recited in claim 1, wherein the removal of said material is obtained by locally grinding mechanically.
Claim 5
Dependent Claim
45 words
A method as recited in claim 1, wherein the distance betwEen the inner limit of the surface over which the material is removed and the boundary of the junction is at least about 10 times the thickness of the peripheral zone of the diffused region.
Claim 6
Dependent Claim
26 words
A method as recited in claim 1, wherein the step of diffusing and the step of removing said material are carried out so that the equation
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) | 1978-06-16 | 1978-12-16 | 1979-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-16 | 1982-12-16 | 1983-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-16 | 1986-12-16 | 1987-06-17 | $7700.00 | Window Closed / Lapsed |