US4258375A
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Gax In1-x Asy P1-y /InP Avalanche photodiode and method for its fabrication
Assignee: Massachusetts Institute of Technology
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Filing: 1979-04-09
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Granted: 1981-03-24
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Expires: 1999-04-09
Abstract
Abstract An improved avalanche photodiode having an active layer of Ga x In 1-x As y P 1-y containing a p-n junction and a window layer grown epitaxially to an n + substrate is disclosed herein, as well as methods for its fabrication.
Inventors
- 👤 Jaw J. Hsieh
- 👤 Charles E. Hurwitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:45
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/22; H10F30/225
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
97 words
An avalanche photodiode, comprising: a. an n+ InP substrate; b. an active layer of Ga x In 1-x As y P 1--y lattice-matched to said substrate and having a p-n junction sufficient to produce an avalanche effect in said photodiode; c. a window layer lattice-matched to said substrate, said window layer having a bandgap equal to or higher than the bandgap of said active layer and being formed from InP or a quaternary having the formula Ga x 'In 1-x 'As y 'P 1-y ' wherein 0≦x'≦x and 0≦y'≦y; and, d. ohmic contacts to said avalanche photodiode.
Claim 2
Dependent Claim
97 words
An avalanche photodiode, comprising: a. an n+ InP substrate; b. an active layer of Ga x In 1-x As y P 1--y lattice-matched to said substrate and having a p-n junction sufficient to produce an avalanche effect in said photodiode; c. a window layer lattice-matched to said substrate, said window layer having a bandgap equal to or higher than the bandgap of said active layer and being formed from InP or a quaternary having the formula Ga x 'In 1-x 'As y 'P 1-y ' wherein 0≦x'≦x and 0≦y'≦y; and, d. ohmic contacts to said avalanche photodiode.
Claim 3
Dependent Claim
26 words
An avalanche photodiode of claim 1 wherein said window layer is formed from Ga x 'In 1-x 'As y 'P 1-y , wherein 0≦x'≦x and 0≦y'≦y.
Claim 4
Dependent Claim
16 words
An avalanche photodiode of claim 2 wherein said substrate has a substantially (111)B of (100) orientation.
Claim 5
Dependent Claim
23 words
An avalanche photodiode of claim 3 wherein said active layer of Ga x In 1-x As y P 1-y contains a p-n homojunction.
Claim 6
Independent Claim
117 words
The method of fabricating an avalanche photodiode, comprising: a. depositing an epitaxial lattice-matched active layer of n-type Ga x In 1-x As y P 1-y on an n+-type InP substrate; b. depositing an epitaxial lattice-matched window layer of Ga x 'In 1-x 'As y 'P 1-y ', wherein 0≦x'≦x and 0≦y'≦y, over said Ga x In 1-x As y P 1-y layer; c. diffusing or implanting p-type dopant into said window layer of Ga x 'In 1-x 'As y 'P 1-y ' and said active layer of Ga x In 1-x As y P 1-y to form a p-n junction therein; and, d. applying ohmic contacts to said substrate and said window layer of said avalanche photodiode.
Claim 7
Independent Claim
117 words
The method of fabricating an avalanche photodiode, comprising: a. depositing an epitaxial lattice-matched active layer of n-type Ga x In 1-x As y P 1-y on an n+-type InP substrate; b. depositing an epitaxial lattice-matched window layer of Ga x 'In 1-x 'As y 'P 1-y ', wherein 0≦x'≦x and 0≦y'≦y, over said Ga x In 1-x As y P 1-y layer; c. diffusing or implanting p-type dopant into said window layer of Ga x 'In 1-x 'As y 'P 1-y ' and said active layer of Ga x In 1-x As y P 1-y to form a p-n junction therein; and, d. applying ohmic contacts to said substrate and said window layer of said avalanche photodiode.
Claim 8
Dependent Claim
25 words
The method of claim 5 wherein said p-n junction is 0 to about 1.5 μm from the interface between said active and said window layers.
Claim 9
Dependent Claim
16 words
A method of claim 6 wherein said avalanche photodiode is etched to provide a mesa structure.
Claim 10
Dependent Claim
30 words
A method of claim 6 wherein a guard ring structure is formed in the n-type Ga x In 1-x As y P 1-y active layer by diffusing therein p-type dopant.
Claim 11
Dependent Claim
30 words
A method of claim 6 wherein a guard ring structure is formed in said n-type Ga x In 1-x As y P 1-y active layer by implanting therein p-type ions.
Claim 12
Dependent Claim
34 words
A method of claim 6 wherein the surface of said n +-type InP substrate is melted back prior to deposition of said layer of n-type Ga x In 1-x As y P 1-y .
Claim 13
Dependent Claim
36 words
A method of claim 6 wherein a buffer layer of InP is deposited upon said n + -type InP substrate prior to depositing said n-type Ga x In 1-x As y P 1-y active layer thereon.
Claim 14
Dependent Claim
12 words
A method of claim 6 wherein said p-type dopant comprises zinc atoms.
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) | 1984-03-23 | 1984-09-22 | 1985-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-23 | 1988-09-22 | 1989-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-23 | 1992-09-22 | 1993-03-24 | $7700.00 | Window Closed / Lapsed |