US4763176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal-semiconductor-metal schottky photodiode
Assignee: Fujitsu Ltd
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Filing: 1987-01-07
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Granted: 1988-08-09
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Expires: 2007-01-07
Abstract
Abstract A metal-semiconductor-metal photodiode comprises a semiconductor layer and a cathode electrode and an anode electrode which are formed on the semiconductor layer and are made of such mutually different electrode materials that the cathode electrode has a Schottky barrier height φ bn from a conduction band satisfying φ bn >Eg/2 and the anode electrode has a Schottky barrier height φ bp from a valence band satisfying φ bp >Eg/2, where Eg denotes the energy band gap.
Inventors
- 👤 Masanori Ito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:07
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/10; H10F39/103; H10F30/00; H10F30/20; H10F30/21; H10F30/22; H10F30/227; H10F30/2275; H10F10/00; H10F10/10; H10F10/18; Y; Y02; Y02E; Y02E10/00; Y02E10/50
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
166 words
A metal-semiconductor-metal photodiode having reduced dark current characteristics comprising: a semiconductor layer having an energy band gap Eg; a cathode electrode formed on said semiconductor layer so as to form a first Schottky barrier with said semiconductor layer, said cathode electrode being made of a first electrode material having a first Schottky barrier height φ bn from a conduction band of said semiconductor layer satisfying the relationship φ bn >Eg/2; an anode electrode formed on said semiconductor layer so as to form a second Schottky barrier with said semiconductor layer, said anode electrode being made of a second electrode material different from said first electrode material and having a second Schottky barrier height φ bp from a valence band of said semiconductor layer satisfying the relationship φ bp >Eg/2; and a bias voltage means, operatively connected between said cathode electrode and said anode electrode, for applying a bias voltage so as to make the voltage of said anode electrode higher than that of said cathode electrode.
Claim 2
Dependent Claim
166 words
A metal-semiconductor-metal photodiode having reduced dark current characteristics comprising: a semiconductor layer having an energy band gap Eg; a cathode electrode formed on said semiconductor layer so as to form a first Schottky barrier with said semiconductor layer, said cathode electrode being made of a first electrode material having a first Schottky barrier height φ bn from a conduction band of said semiconductor layer satisfying the relationship φ bn >Eg/2; an anode electrode formed on said semiconductor layer so as to form a second Schottky barrier with said semiconductor layer, said anode electrode being made of a second electrode material different from said first electrode material and having a second Schottky barrier height φ bp from a valence band of said semiconductor layer satisfying the relationship φ bp >Eg/2; and a bias voltage means, operatively connected between said cathode electrode and said anode electrode, for applying a bias voltage so as to make the voltage of said anode electrode higher than that of said cathode electrode.
Claim 3
Dependent Claim
40 words
A metal-semiconductor-metal photodiode as claimed in claim 1 in which said first electrode material is selected from a group of gold, platinum, titanium and aluminum, and said second electrode material is selected from a group of indium and tungsten silicide.
Claim 4
Dependent Claim
27 words
A metal-semiconductor-metal photodiode as claimed in claim 2 in which said second electrode material is WSi x , where x is a range of 0.5 to 0.8.
Claim 5
Dependent Claim
46 words
A metal-semiconductor-metal photodiode as claimed in claim 1 which further comprises an additional layer formed on at least one of said cathode electrode and said anode electrode, said additional layer being made of a material selected from a group of indium tin oxide and indium oxide.
Claim 6
Dependent Claim
50 words
A metal-semiconductor-metal photodiode as claimed in claim 4 in which said additional layer has a film thickness in the order to 2000 Å, and said cathode electrode and/or said anode electrode having said additional layer formed thereon has a film thickness in a range of 50 Å to 100 Å.
Claim 7
Dependent Claim
26 words
A metal-semiconductor-metal photodiode as claimed in claim 1 in which said semiconductor layer is an active layer, said active layer being formed on a semiinsulating substrate.
Claim 8
Dependent Claim
18 words
A metal-semiconductor-metal photodiode as claimed in claim 6 in which said active layer is made of gallium arsenide.
Claim 9
Dependent Claim
45 words
A metal-semiconductor-metal photodiode as claimed in claim 6 in which said cathode electrode and said anode electrode are arranged on said active layer in the form of teeth of a comb so that teeth portions of said cathode electrode and said anode electrode occur alternately.
References Cited (Backward Citations)
GB1082358A
Cited
US3700980A
Cited
JPS5450288A
Cited
US4345107A
Cited
EP0063421A2
Cited
US4514579A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-09 | 1992-02-08 | 1992-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-09 | 1996-02-08 | 1996-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-09 | 2000-02-08 | 2000-08-09 | $7700.00 | Window Closed / Lapsed |