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US4620210A Expired / Lapsed US ⏱️ 0.0 years remaining

Phototransistor of the type having an emitter-base heterojunction

Assignee: Individual
•
Filing: 1984-08-17
•
Granted: 1986-10-28
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Expires: 2004-08-17
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Abstract

Abstract A phototransistor comprising a substrate (9), a collector layer (2), a base layer (3), and an emitter layer (4) is disclosed. The base layer (3) is of a first composite III-V semiconductor material with a first type of doping and the emitter layer (4) is of a second composite III-V semiconductor material. A diffusion well (6), of the first type of doping extends on a main part of the emitter layer (4) down to the base layer. The remaining part of the emitter layer (4) is of a second type of doping. The main part of the emitter layer (4) has an area at least 100 times larger than the area of the remaining part. A contact layer with the second type of doping is deposited on the remaining part of the emitter layer (4) with an emitter contact on the contact layer, and a base contact on an extremity of the diffusion well (6). Such a phototransistor thus comprises a heterojunction transistor under the emitter contact and a homojunction photodiode under the diffusion well (6), and the diffusion well (6) is transparent in most of its thickness to light radiation to be detected.

Inventors

  • 👤 Andre Scavennec
  • 👤 David Ankri

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 19:10
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/24; H10F30/245

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 204 words
A phototransistor comprising a substrate, a collector layer disposed on said substrate, a base layer disposed on said collector layer, an emitter layer disposed on said base layer, said base layer being of a first composite III-V semiconductor material with a first type of doping and said emitter layer of a second composite III-V semiconductor material, a diffusion well of said first type of doping extending on a main part of said emitter layer down to said base layer, a remainder part of said emitter layer being of a second type of doping, said main part of emitter layer with said diffusion well having an area of at least 100 times larger than the area of said remainder part, said collector layer having said second type of doping, a contact layer with said second type of doping on said remainder part of said emitter layer, an emitter contact on said contact layer, a base contact on an extremity of said diffusion well and a collector contact connected to said collector layer, said phototransistor thus comprising a homojunction photodiode under said diffusion well, said diffusion well being transparent in most of its thickness to light radiation to be detected to perform optical and electronic functions.
Claim 2
Dependent Claim 204 words
A phototransistor comprising a substrate, a collector layer disposed on said substrate, a base layer disposed on said collector layer, an emitter layer disposed on said base layer, said base layer being of a first composite III-V semiconductor material with a first type of doping and said emitter layer of a second composite III-V semiconductor material, a diffusion well of said first type of doping extending on a main part of said emitter layer down to said base layer, a remainder part of said emitter layer being of a second type of doping, said main part of emitter layer with said diffusion well having an area of at least 100 times larger than the area of said remainder part, said collector layer having said second type of doping, a contact layer with said second type of doping on said remainder part of said emitter layer, an emitter contact on said contact layer, a base contact on an extremity of said diffusion well and a collector contact connected to said collector layer, said phototransistor thus comprising a homojunction photodiode under said diffusion well, said diffusion well being transparent in most of its thickness to light radiation to be detected to perform optical and electronic functions.
Claim 3
Dependent Claim 36 words
A phototransistor according to claim 1, wherein said first semiconducting material is GaAs, said second semiconducting material is GaAlAs, said first type of doping is p type and said second type of doping is n type.
Claim 4
Dependent Claim 56 words
A phototransistor according to claim 1, wherein said first semiconducting material is GaAlAs with a first Al concentration and said second semiconducting material is GaAlAs with a second Al concentration, said second concentration being lower than said first concentration, said first type of doping is p type and said second type of doping is n type.
Claim 5
Dependent Claim 25 words
A phototransistor according to claim 1, wherein said diffusion well has an area larger than the area of a circle of 50 μm of diameter.

References Cited (Backward Citations)

US3881113A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1989-10-27 1990-04-28 1990-10-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1993-10-27 1994-04-28 1994-10-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1997-10-27 1998-04-28 1998-10-28 $7700.00 Window Closed / Lapsed

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