US4318752A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heterojunction semiconductor laser fabrication utilizing laser radiation
Assignee: AT&T Inc
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Filing: 1980-05-16
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Granted: 1982-03-09
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Expires: 2000-05-16
Abstract
Abstract A stripe geometry is fabricated in a laser-diode structure having a plurality of epitaxial layers, including in tandem an undoped active semiconductor layer (3), a p-doped semiconductor layer (4), a moderately n-doped semiconductor layer (5) and a heavily p+-doped layer (6) by focusing laser radiation on the n-doped semiconductor layer (5). The laser radiation is chosen to have a wavelength which passes through the p+-doped layer (6) without absorption. When the laser radiation is absorbed in the n-doped layer, heat is generated which causes diffusion of p-dopant from the two adjacent layers to convert the exposed region to p-type. As the laser beam is scanned, a stripe having a forward pn junction for laser action is formed.
Inventors
- 👤 Ping K. Tien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:47
CPC Classifications
H; H10; H10P; H10P32/00; H10D; H10D62/00; H10D62/80; H10D62/82; H10D62/824; H10P34/00; H10P34/40; H10P34/42; Y; Y10; Y10S; Y10S148/00; Y10S148/084
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
114 words
A method of forming a p-doped selected area in an n-doped layer of a structure having a plurality of epitaxial layers on a substrate, said epitaxial layers including in tandem a first p-doped semiconductor layer (4), an n-doped semiconductor layer (5) and a second p-doped semiconductor layer (6), said method comprising: focusing radiation from a laser source through said second p-doped semiconductor layer (6) and onto said selected area of said n-doped semiconductor layer (5) to provide heating of said area, which heating causes diffusion of p-dopant into said selected area, whereby said selected area is converted to p-type, said radiation having a wavelength which is not absorbed by said second p-doped semiconductor layer.
Claim 2
Independent Claim
114 words
A method of forming a p-doped selected area in an n-doped layer of a structure having a plurality of epitaxial layers on a substrate, said epitaxial layers including in tandem a first p-doped semiconductor layer (4), an n-doped semiconductor layer (5) and a second p-doped semiconductor layer (6), said method comprising: focusing radiation from a laser source through said second p-doped semiconductor layer (6) and onto said selected area of said n-doped semiconductor layer (5) to provide heating of said area, which heating causes diffusion of p-dopant into said selected area, whereby said selected area is converted to p-type, said radiation having a wavelength which is not absorbed by said second p-doped semiconductor layer.
Claim 3
Dependent Claim
30 words
A method of forming a stripe geometry in accordance with claim 1 which further includes the step of scanning said radiation along a stripe in said n-doped semiconductor layer (5).
Claim 4
Independent Claim
134 words
A method of forming a p-doped selected area in a n-doped semiconductor layer of a laser-diode structure having a plurality of epitaxial layers on a substrate, said epitaxial layers including in tandem an undoped semiconductor layer (2) designed for emitting radiation of a predetermined wavelength, a p-doped semiconductor layer (4), a moderately n-doped semiconductor layer (5) and a heavily p + -doped semiconductor layer (6), said method comprising: focusing radiation from a laser source through said p + -doped semiconductor layer (6) and onto said selected area of said n-doped seminconductor layer (5) to provide heating of said area, which heating causes diffusion of p-dopant into said selected area, whereby said selected area is converted to p-type, said radiation having a wavelength which is not absorbed by said p + -doped semiconductor layer (6).
Claim 5
Independent Claim
134 words
A method of forming a p-doped selected area in a n-doped semiconductor layer of a laser-diode structure having a plurality of epitaxial layers on a substrate, said epitaxial layers including in tandem an undoped semiconductor layer (2) designed for emitting radiation of a predetermined wavelength, a p-doped semiconductor layer (4), a moderately n-doped semiconductor layer (5) and a heavily p + -doped semiconductor layer (6), said method comprising: focusing radiation from a laser source through said p + -doped semiconductor layer (6) and onto said selected area of said n-doped seminconductor layer (5) to provide heating of said area, which heating causes diffusion of p-dopant into said selected area, whereby said selected area is converted to p-type, said radiation having a wavelength which is not absorbed by said p + -doped semiconductor layer (6).
Claim 6
Dependent Claim
34 words
A method of forming a stripe geometry in said laser-diode structure in accordance with claim 3, which further includes the step of scanning said radiation along a stripe in said n-doped semiconductor layer (5).
Claim 7
Dependent Claim
29 words
A method of forming a stripe geometry in a laser-diode structure as defined in claim 4 wherein said laser source is a Nd:YAG laser, for producing 1.06 micron radiation.
Claim 8
Dependent Claim
49 words
A method of forming a striped geometry in a laser-diode structure as defined in claim 5 wherein said radiation from said Nd:YAG laser having a pulse width of 60 nanoseconds and an energy density of 2 J/cm 2 is focused to a spot size having a 1 micron diameter.
Claim 9
Dependent Claim
28 words
A method of forming a striped geometry in a laser-diode structure as defined in claim 5 wherein said p + -doped semiconductor layer (6) is p + -InP.
Claim 10
Dependent Claim
59 words
A method of forming a striped geometry in a laser-diode structure as defined in claim 5 wherein said p + -doped semiconductor layer (6) is a p + quaternary of the form In 1-x Ga x As y P 1-y , x and y are chosen so that the bandgap wavelength of said quaternary is less than 1.06μ microns.
Claim 11
Dependent Claim
61 words
A method of forming a striped geometry in a laser-diode structure as defined in claim 7 wherein said p-doped semiconductor layer (4) and said n-doped semiconductor layer (5) are both quaternaries of the form In 1-x Ga x As y P 1-y , x and y being chosen such that the bandgap wavelength of said quaternary is greater than 1.06μ microns.
Claim 12
Dependent Claim
71 words
A method of forming a striped geometry in a laser-diode structure as defined in claim 9, said method further comprising the step of focusing radiation from a second laser source onto said undoped semiconductor layer for annealing said layer, said radiation from said second source having a wavelength which is not absorbed by said p + -doped semiconductor layer (6), said n-doped semiconductor layer (5) and said p-doped semiconductor layer (4).
Claim 13
Dependent Claim
30 words
A method of forming a striped geometry in a laser-diode structure as defined in claim 10, wherein said second laser source comprises an F-center laser, for producing 1.2 micron radiation.
Claim 14
Dependent Claim
80 words
A method of forming a striped geometry in a laser-diode structure as defined in claim 11 wherein said p-doped layer (4) is p-In 0 .829 Ga 0 .171 As 0 .373 P 0 .627, said n-doped layer (5) is n-In 0 .829 Ga 0 .171 As 0 .373 P 0 .627 and said undoped semiconductor layer (3) is In 0 .70 Ga 0 .30 As 0 .636 P 0 .364 which undoped semiconductor layer is absorbing to 1.2 micron radiation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-03-08 | 1985-09-07 | 1986-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-08 | 1989-09-07 | 1990-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-08 | 1993-09-07 | 1994-03-09 | $7700.00 | Window Closed / Lapsed |