Patent US3633059A successfully refreshed from Google Patents.
US3633059A
Expired / Lapsed
US
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Electroluminescent pn junction semiconductor device for use at higher frequencies
Assignee: Semiconductor Research Foundation
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Filing: 1970-03-13
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Granted: 1972-01-04
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Expires: 1990-03-13
Abstract
Abstract Disclosed herein are PN junction semiconductors comprising electroluminescent devices having impurity concentration which decreases as the distance from the PN junction increases. When pulses having a duration of 10 6 to 10 10 seconds are applied forwardly across the PN junction the minority carriers are rapidly and efficiently injected into the varied concentration portion and then rapidly transferred to an adjacent long lifetime portion by the action of the established field. The minority carriers which reach and are accumulated on the adjacent long lifetime portion cause a slow transition wherein the minority carriers are recombined with the majority carriers to emit light having the effect of afterglow.
Inventors
- 👤 Jun-Ichi Nishizawa
- 👤 Tokuzo Sukegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:27
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
194 words
An electroluminescent semiconductor device for use at higher frequencies, comprising a wafer of semiconductive material having a first region of one conductivity type and a second region of opposite conductivity type arranged to define a PN junction therebetween, said region having a distribution of impurity concentration which first increases as a distance from the PN junction increases, after which said impurity concentration decreases with a further increase in distance from the PNjunction, said distribution establishing a drift field by drifting the minority carriers injected through the PN junction in a direction to increase their distance from the PN-junction; whereupon said impurity concentration remains substantially constant as the distance from the PN-junction is increased further for providing a relatively long lifetime portion on which the minority carriers transferred thereto by the action of said drift field are accumulated and emit light with afterglow through a slow transition of recombination between minority and majority carriers in said device, and wherein upon a further increase in distance from the PN junction the impurity concentration again increases to establish a drift field in a direction to prevent the minority carriers from diffusing away from said long lifetime portion.
Claim 2
Dependent Claim
194 words
An electroluminescent semiconductor device for use at higher frequencies, comprising a wafer of semiconductive material having a first region of one conductivity type and a second region of opposite conductivity type arranged to define a PN junction therebetween, said region having a distribution of impurity concentration which first increases as a distance from the PN junction increases, after which said impurity concentration decreases with a further increase in distance from the PNjunction, said distribution establishing a drift field by drifting the minority carriers injected through the PN junction in a direction to increase their distance from the PN-junction; whereupon said impurity concentration remains substantially constant as the distance from the PN-junction is increased further for providing a relatively long lifetime portion on which the minority carriers transferred thereto by the action of said drift field are accumulated and emit light with afterglow through a slow transition of recombination between minority and majority carriers in said device, and wherein upon a further increase in distance from the PN junction the impurity concentration again increases to establish a drift field in a direction to prevent the minority carriers from diffusing away from said long lifetime portion.
Claim 3
Dependent Claim
36 words
An electroluminescent semiconductor device as claimed in claim 1 wherein said first region is greater in the effective width of a forbidden band than said second region thereby to increase the efficiency of minority carrier injection.
Claim 4
Dependent Claim
235 words
An electroluminescent semiconductor device having distributed effective band gaps, for use at higher frequencies, comprising a wafer of semiconductive material containing donor and acceptor impurities, and including a first region of one conductivity type and a second region of opposite conductivity type arranged to define a PN-junction with said first region, said first region having a substantially constant impurity concentration as measured from the PN-junction; said second region having a first portion adjacent said PN-junction having an impurity concentration distribution which first increases uniformly as the distance from the PN-junction increases, and then decreases upon a further increase in distance from the PN-junction for establishing a drift field for drifting minority carriers injected through the PN-junction in a direction to increase the distance from the PN-junction; a second portion spaced from said junction and disposed adjacent said first portion and having an impurity concentration which decreases to a minimum to provide a relatively long lifetime portion on which the minority carriers transferred thereto through said first portion by the action of said drift field are accumulated and emit light with afterglow through slow transition; and a third portion spaced from said first portion and disposed adjacent said second portion therein and having an effective impurity concentration which increases as the distance from the PN junction increases for establishing a drift field in a direction which prevents the minority carriers from diffusing into said third portion.
Claim 5
Dependent Claim
235 words
An electroluminescent semiconductor device having distributed effective band gaps, for use at higher frequencies, comprising a wafer of semiconductive material containing donor and acceptor impurities, and including a first region of one conductivity type and a second region of opposite conductivity type arranged to define a PN-junction with said first region, said first region having a substantially constant impurity concentration as measured from the PN-junction; said second region having a first portion adjacent said PN-junction having an impurity concentration distribution which first increases uniformly as the distance from the PN-junction increases, and then decreases upon a further increase in distance from the PN-junction for establishing a drift field for drifting minority carriers injected through the PN-junction in a direction to increase the distance from the PN-junction; a second portion spaced from said junction and disposed adjacent said first portion and having an impurity concentration which decreases to a minimum to provide a relatively long lifetime portion on which the minority carriers transferred thereto through said first portion by the action of said drift field are accumulated and emit light with afterglow through slow transition; and a third portion spaced from said first portion and disposed adjacent said second portion therein and having an effective impurity concentration which increases as the distance from the PN junction increases for establishing a drift field in a direction which prevents the minority carriers from diffusing into said third portion.
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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |