US3794891A
Expired / Lapsed
US
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High speed response phototransistor and method of making the same
Assignee: Mitsubishi Electric Corp
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Filing: 1973-03-05
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Granted: 1974-02-26
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Expires: 1993-03-05
Abstract
Abstract A high speed response phototransistor comprises a plurality of pairs of base layers and emitter layers formed with progressive diffusions on a common collector, and an emitter electrode which commonly connects the plurality of emitter layers. The width of a depletion layer between the base and emitter layers is broadened so that a narrow base-emitter layer whose area is significantly smaller than a planar spread of the depletion layer.
Inventors
- 👤 S Takamiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:52
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/24; H10F30/245; H10F99/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
84 words
A high speed response phototransistor which comprises: a plurality of pairs of base layers and emitter layers which are progressively diffused on a common collector, forming a plurality of base-emitter layers, an emitter electrode which commonly connects said plurality of emitter layers, and a depletion region which has a large width compared to said base layers and emitter layers between said base layers and said collector 1 thereby forming base-emitter layers having an area smaller than a planar spread area of the depletion region.
Claim 2
Dependent Claim
84 words
A high speed response phototransistor which comprises: a plurality of pairs of base layers and emitter layers which are progressively diffused on a common collector, forming a plurality of base-emitter layers, an emitter electrode which commonly connects said plurality of emitter layers, and a depletion region which has a large width compared to said base layers and emitter layers between said base layers and said collector 1 thereby forming base-emitter layers having an area smaller than a planar spread area of the depletion region.
Claim 3
Dependent Claim
14 words
A high speed response phototransistor according to claim 1 having a thin base layer.
Claim 4
Dependent Claim
24 words
A high speed response phototransistor according to claim 1 wherein said depletion region is formed between said base layers and adjacent said emitter layers.
Claim 5
Dependent Claim
39 words
A high speed response phototransistor according to claim 1 wherein alternatively a length or width of said base layer is smaller than a depth of an operation region defined by a thickness of depletion region and a diffusion length.
Claim 6
Dependent Claim
41 words
A high speed response phototransistor according to claim 1 wherein a length and width of said base layer is smaller than a depth of an operation region defined by a thickness of a high electric field region and a diffusion length.
Claim 7
Dependent Claim
41 words
A high speed response phototransistor according to claim 1 wherein the length of a nondepletion base region in a bias condition is smaller than the spread of said depletion region between said base layers and said collector in a bias condition.
Claim 8
Dependent Claim
52 words
A method of manufacturing a high speed response phototransistor of claim 1 comprising the steps of: diffusing a base layer from a diffusion window formed by one photoetching in a nonoxidative atmosphere; treating said diffused base layer by etching for a short time; and diffusing an emitter layer from said diffusion window.
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) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |