US5228048A
Expired / Lapsed
US
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Semiconductor laser device
Assignee: KDDI Corp
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Filing: 1992-02-04
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Granted: 1993-07-13
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Expires: 2012-02-04
Abstract
Abstract A semiconductor laser device includes a p type semiconductor substrate, an active layer having a smaller energy band gap than the p type semiconductor substrate and an n type semiconductor layer having a larger energy band gap than the active layer successively formed on the p type semiconductor substrate, a mesa formed by selectively etching the semiconductor substrate, active layer, and n type semiconductor layer, p-n-p layers having larger energy band gaps than the active layer and disposed at both sides of the mesa, a small energy band gap layer having a smaller energy band gap than the p type semiconductor substrate and disposed on the p-n-p layers, and an n type semiconductor layer disposed on the small energy band gap layer and on the n type semiconductor layer. The small energy band gap layers decrease the current flowing through the thyristor structure and are disposed close to the active region but in a different processing step from the formation of the active layer. A waveguide structure in which the active layer is surrounded by semiconductor layers having larger energy band gaps is realized.
Inventors
- 👤 Akira Takemoto
- 👤 Etsuji Omura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 00:46
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/20; H01S5/22; H01S5/227; H01S5/0014; H01S5/0035; H01S5/2275; H01S5/2277
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
192 words
A semiconductor laser device comprising: a p type semiconductor substrate having a first energy band gap; an active layer comprising a semiconductor material having a second energy band gap smaller than the first energy band gap and a first n type semiconductor layer having an energy band gap larger than the second energy band gap successively disposed on said p type semiconductor substrate; a stripe shape mesa, formed by selectively etching said semiconductor substrate, active layer, and first n type semiconductor layer, including said active layer and first n type semiconductor layer; a first p type semiconductor layer, a second n type semiconductor layer, and a second p type semiconductor layer, each having an energy band gap larger than the second energy band gap successively disposed on said semiconductor substrate at and contacting opposite sides of said mesa; a small energy band gap layer having a third energy band gap smaller than the first energy band gap and disposed on said second p type semiconductor layer; and a third n type semiconductor layer disposed on said small energy band gap layer and on said mesa contacting said first n type semiconductor layer.
Claim 2
Dependent Claim
192 words
A semiconductor laser device comprising: a p type semiconductor substrate having a first energy band gap; an active layer comprising a semiconductor material having a second energy band gap smaller than the first energy band gap and a first n type semiconductor layer having an energy band gap larger than the second energy band gap successively disposed on said p type semiconductor substrate; a stripe shape mesa, formed by selectively etching said semiconductor substrate, active layer, and first n type semiconductor layer, including said active layer and first n type semiconductor layer; a first p type semiconductor layer, a second n type semiconductor layer, and a second p type semiconductor layer, each having an energy band gap larger than the second energy band gap successively disposed on said semiconductor substrate at and contacting opposite sides of said mesa; a small energy band gap layer having a third energy band gap smaller than the first energy band gap and disposed on said second p type semiconductor layer; and a third n type semiconductor layer disposed on said small energy band gap layer and on said mesa contacting said first n type semiconductor layer.
Claim 3
Dependent Claim
48 words
The semiconductor laser device of claim 1 wherein said first p type semiconductor layer, second n type semiconductor layer, second p type semiconductor layer, and third n type semiconductor layer comprises a p-n-p-n thyristor structure, said small energy band gap layer suppressing current flow through said thyristor structure.
Claim 4
Dependent Claim
25 words
The semiconductor laser device of claim 2 wherein the third energy band gap is selected to suppress the current flowing through said p-n-p-n thyristor structure.
Claim 5
Dependent Claim
24 words
The semiconductor laser device of claim 1 wherein said small energy band gap layer and said active layer are formed in different process steps.
Claim 6
Dependent Claim
32 words
The semiconductor laser device of claim 1 wherein said mesa includes opposed edges along said stripe and said small energy band gap layer includes two edges contacting respective edges of said mesa.
Claim 7
Dependent Claim
21 words
The semiconductor laser device of claim 1 wherein said small energy band gap layer is no more than 0.1 micron thick.
Claim 8
Dependent Claim
16 words
A semiconductor laser device in accordance with claim 1 wherein said semiconductor substance in a substrate.
Claim 9
Dependent Claim
24 words
The semiconductor laser device of claim 1 wherein said semiconductor substrate comprises a p type semiconductor layer disposed on a p type semiconductor substrate.
Claim 10
Dependent Claim
29 words
The semiconductor laser device of claim 8 including a p side electrode disposed on said substrate and an n side electrode disposed on said third n type semiconductor layer.
Claim 11
Dependent Claim
29 words
The semiconductor laser device of claim 1 including a p side electrode disposed on said substrate and an n side electrode disposed on said third n type semiconductor layer.
Claim 12
Dependent Claim
39 words
The semiconductor laser device of claim 1 including stripe-shaped grooves disposed on opposite sides of the mesa extending from and through said third n type semiconductor layer side and into said p type semiconductor substrate to decrease parasitic capacitance.
Claim 13
Dependent Claim
47 words
The semiconductor laser device of claim 1 wherein said p type semiconductor substrate, first p type semiconductor layer, second n-type semiconductor layer, second p type semiconductor layer, and third n type semiconductor layer are InP and said active layer and small energy band gap layer are InGaAsP.
Claim 14
Dependent Claim
41 words
The semiconductor laser device of claim 1 including an n type contact layer disposed on said third n type semiconductor layer, a p side electrode disposed on said substrate, and an n side electrode disposed on said n type contact layer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1996-07-12 | 1997-01-11 | 1997-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-12 | 2001-01-11 | 2001-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-12 | 2005-01-11 | 2005-07-13 | $7700.00 | Window Closed / Lapsed |