US4568959A
Expired / Lapsed
US
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Photomultiplier
Assignee: International Business Machines Corp
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Filing: 1983-06-02
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Granted: 1986-02-04
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Expires: 2003-06-02
Abstract
Abstract A semiconductor structure is provided with progressively changing band gap in a plurality of stages each at an abrupt interface with an asymmetry in the band gap widths such that the major difference in energy gap discontinuity is in the band favoring a particular type of carrier. The transition regions between the progressive material sections are smaller than the carrier mean free path so as to provide kinetic energy for efficient carrier multiplication with reduced noise as the carriers traverse through the device.
Inventors
- 👤 Leroy L. Chang
- 👤 Frank F. Fang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:13
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/22; H10F30/222
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
103 words
In a converter of light to electrical signals employing a plurality of abutting regions of monocrystalline semiconductor material of alternating opposed conductivity type having a progressively decreasing band gap in a direction away from a light incident surface, the improvement for providing multiplied photo-produced carriers comprising decreasing said band gap in a series of step corresponding to said abutting regions, each said step being of the order of less than the mean free path of an electron in said direction away from said light incident surface and the predominant change in band gap being in the band that favors a specific carrier type.
Claim 2
Dependent Claim
103 words
In a converter of light to electrical signals employing a plurality of abutting regions of monocrystalline semiconductor material of alternating opposed conductivity type having a progressively decreasing band gap in a direction away from a light incident surface, the improvement for providing multiplied photo-produced carriers comprising decreasing said band gap in a series of step corresponding to said abutting regions, each said step being of the order of less than the mean free path of an electron in said direction away from said light incident surface and the predominant change in band gap being in the band that favors a specific carrier type.
Claim 3
Dependent Claim
28 words
The converter of claim 1 wherein the favored carrier is electrons and the conduction band discontinuity is larger than the valence band discontinuity at each of said steps.
Claim 4
Dependent Claim
29 words
The converter of claim 1 wherein the favored carrier is holes and the valence band discontinuity is much larger than the conduction band discontinuity at each of said steps.
Claim 5
Dependent Claim
32 words
The converter of claim 2 wherein said semiconductor material is (Ga x In 1-x )As where x varies from 0 to 1 at in essentially 0.25 increments at each successive said step.
Claim 6
Dependent Claim
31 words
The converter of claim 3 wherein said material is Ga(Sb x As 1-x ) where x varies from 0 to 1 at in essentially 0.25 increments at each successive said step.
References Cited (Backward Citations)
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US3995303A
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US4171996A
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US4053920A
Cited
US4206002A
Cited
US4250515A
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US4250516A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |