EP0319207A2
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EP
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A method of producing a semi-conducteur device having a disordered superlattice
Assignee: Mitsubishi Electric Corp
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Filing: 1988-11-25
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Granted: —
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Expires: 2008-11-25
Abstract
Abstract A method of producing a semiconductor device such as a semiconductor laser having a controllably disordered superlattice. The superlattice (3) is grown epitaxially and in the same epitaxial growth process a heavily selenium doped semiconductor layer (7) is also grown in a known spatial relationship to the superlattice (3). The doped layer (7) is patterned as by etching and then the device is annealed to diffuse selenium impurities from the doped layer (7). The time and temperature of annealing are controlled such that the impurities diffuse into and thereby disorder regions (8) of the superlattice layer (3), leaving a non-disordered region (3) which can serve as a resonator in a laser.
Inventors
- 👤 Takashi C/O Mitsubishi Denki K. K. Murakami
- 👤 Kaname C/O Mitsubishi Denki K. K. Otaki
- 👤 Hisao C/O Mitsubishi Denki K. K. Kumabe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 15:38
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P14/38; H10P14/3824; B; B82; B82Y; B82Y20/00; H01; H01S; H01S5/00; H01S5/20; H01S5/30; H01S5/34; H01S5/2054; H01S5/2059; Y; Y10; Y10S; Y10S148/00; Y10S148/037; Y10S148/095
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
120 words
A method of producing a semiconductor device having a semiconductor superlattice active region bounded by a disordered region, the method comprising the steps of: conducting an epitaxial growth phase which includes growing a superlattice layer and as a final layer a selenium doped semiconductor layer which has a predetermined spatial relationship to the superlattice layer, removing a portion of the selenium doped semiconductor layer to produce a predetermined pattern therein, annealing the semiconductor device to diffuse the selenium dopant from the doped layer, controlling the time and temperature of annealing to cause the selenium dopant to diffuse into and thereby disorder a part of the superlattice active layer leaving a non-disordered region determined by the pattern of the doped layer.
Claim 2
Independent Claim
120 words
A method of producing a semiconductor device having a semiconductor superlattice active region bounded by a disordered region, the method comprising the steps of: conducting an epitaxial growth phase which includes growing a superlattice layer and as a final layer a selenium doped semiconductor layer which has a predetermined spatial relationship to the superlattice layer, removing a portion of the selenium doped semiconductor layer to produce a predetermined pattern therein, annealing the semiconductor device to diffuse the selenium dopant from the doped layer, controlling the time and temperature of annealing to cause the selenium dopant to diffuse into and thereby disorder a part of the superlattice active layer leaving a non-disordered region determined by the pattern of the doped layer.
Claim 3
Dependent Claim
28 words
The method of claim 1 wherein the step of removing comprises producing a mask on the doped layer and etching an unmasked portion of the doped layer away.
Claim 4
Dependent Claim
27 words
The method of claim 2 wherein the step of removing includes producing a mask having a pattern in the form of an unmasked stripe of predetermined width.
Claim 5
Dependent Claim
32 words
The method of claim 2 wherein the epitaxial growth phase includes growing an etching stop layer intermediate the superlattice layer and the doped layer for preventing the etching of the superlattice layer.
Claim 6
Dependent Claim
19 words
The method of claim 1 wherein said semiconductor superlattice is selected from the group comprising AlGaAs, InGaAsP and AlGaInP.
Claim 7
Dependent Claim
22 words
The method of claim 1 in which the step of growing the superlattice layer comprises growing alternating layers of GaAs and AlGaAs.
Claim 8
Dependent Claim
27 words
The method of claim 6 in which the selenium doped semiconductor layer comprises GaAs doped with selenium with a concentration of about at least 5 x 10¹⁸cm⁻³.
Claim 9
Dependent Claim
26 words
The method of claim 7 in which the annealing is conducted at a temperature of at least 800°C. for a period of at least 15 hours.
Claim 10
Independent Claim
106 words
A method of producing a semiconductor buried heterostructure laser device comprising the steps of: conducting an epitaxial growth phase which includes epitaxially growing on a semiconductor substrate successive layers including a lower cladding layer, a superlattice active layer, an upper cladding layer, and a selenium doped semiconductor layer; etching a striped portion from the selenium doped semiconductor layer; and annealing the laser device to diffuse selenium from the selenium doped semiconductor layer, controlling the time and temperature of annealing to cause the selenium dopant to diffuse into and thereby disorder regions of the superlattice active layer bounding a non-disordered stripe region of the superlattice active layer.
Claim 11
Independent Claim
106 words
A method of producing a semiconductor buried heterostructure laser device comprising the steps of: conducting an epitaxial growth phase which includes epitaxially growing on a semiconductor substrate successive layers including a lower cladding layer, a superlattice active layer, an upper cladding layer, and a selenium doped semiconductor layer; etching a striped portion from the selenium doped semiconductor layer; and annealing the laser device to diffuse selenium from the selenium doped semiconductor layer, controlling the time and temperature of annealing to cause the selenium dopant to diffuse into and thereby disorder regions of the superlattice active layer bounding a non-disordered stripe region of the superlattice active layer.
Claim 12
Dependent Claim
33 words
The method of claim 9 wherein the etching step comprises producing a mask on the doped layer leaving the striped portion unmasked, and etching the unmasked striped portion of the doped layer away.
Claim 13
Dependent Claim
19 words
The method of claim 9 wherein said semiconductor superlattice is selected from the group comprising AlGaAs, InGaAsP and AlGaInP.
Claim 14
Dependent Claim
22 words
The method of claim 9 in which the step of growing the superlattice layer comprises growing alternating layers of GaAs and AlGaAs.
Claim 15
Dependent Claim
27 words
The method of claim 12 in which the selenium doped semiconductor layer comprises GaAs doped with selenium with a concentration of about at least 5 x 10¹⁸cm⁻³.
Claim 16
Dependent Claim
26 words
The method of claim 13 in which the annealing is conducted at a temperature of at least 800°C. for a period of at least 15 hours.
Claim 17
Dependent Claim
137 words
A semiconductor laser comprising the combination of an epitaxially grown structure formed of successively grown layers on a semiconductor substrate including a lower cladding layer of a first conductivity type, an active layer comprising a superlattice of alternating quantum well and quantum barrier layers, an upper cladding layer of opposite conductivity type to the lower cladding layer, and a selenium doped semiconductor layer; selenium impurities diffused from the selenium doped layer into the upper cladding and active layers in parallel configuration defining external disordered regions of the superlattice bounding a central non-disordered stripe; wherein the disordered regions have a higher band gap and lower refractive index than the central stripe thereby to cause the central stripe to function as a resonator; and a pair of opposed electrodes on the substrate and on the selenium doped layer, respectively.
Claim 18
Dependent Claim
137 words
A semiconductor laser comprising the combination of an epitaxially grown structure formed of successively grown layers on a semiconductor substrate including a lower cladding layer of a first conductivity type, an active layer comprising a superlattice of alternating quantum well and quantum barrier layers, an upper cladding layer of opposite conductivity type to the lower cladding layer, and a selenium doped semiconductor layer; selenium impurities diffused from the selenium doped layer into the upper cladding and active layers in parallel configuration defining external disordered regions of the superlattice bounding a central non-disordered stripe; wherein the disordered regions have a higher band gap and lower refractive index than the central stripe thereby to cause the central stripe to function as a resonator; and a pair of opposed electrodes on the substrate and on the selenium doped layer, respectively.
Claim 19
Dependent Claim
32 words
The semiconductor laser of claim 15 wherein the semiconductor substrate is GaAs, the superlattice is alternating layers of GaAs and AlGaAs, and the doped semiconductor layer is GaAs heavily doped with selenium.
Claim 20
Dependent Claim
17 words
The semiconductor laser of claim 16 wherein the selenium concentration is about at least 5 x 10¹⁸cm⁻³.
Claim 21
Dependent Claim
20 words
The semiconductor laser of claim 15 wherein the semiconductor superlattice is selected from the group comprising AlGaAs, InGaAsP and AlGaInP.
Claim 22
Dependent Claim
16 words
A semiconductor device having a semiconductor superlative region bounded by a region disordered by selenium dopant.
Claim 23
Dependent Claim
16 words
A semiconductor device having a semiconductor superlative region bounded by a region disordered by selenium dopant.
Claim 24
Dependent Claim
39 words
A buried heterojunction type laser device having a superlattice active layer characterised in that an active region thereof is bounded by regions disordered by selenium dopant so as to have a higher band gap and a lower refractive index.
Claim 25
Dependent Claim
39 words
A buried heterojunction type laser device having a superlattice active layer characterised in that an active region thereof is bounded by regions disordered by selenium dopant so as to have a higher band gap and a lower refractive index.
References Cited (Backward Citations)
No citation records indexed.
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