US5499260A
Expired / Lapsed
US
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Semiconductor laser and a method for fabricating the same
Assignee: Panasonic Holdings Corp
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Filing: 1994-07-29
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Granted: 1996-03-12
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Expires: 2014-07-29
Abstract
Abstract An n-ZnMgSSe lower cladding layer, an n-ZnSSe light guiding layer, an undopad CdZnSe active layer, a p-ZnSSe light guiding layer, a p-ZnMgSSe upper cladding layer, and a p-ZnSe cap layer are successively formed on an n-GaAs substrate. Then, grooves and a ridge are formed in the respective p-type layers by etching. A current blocking layer formed by laminating SiO 2 layers and TiO 2 layers in multiple layers is formed so as to bury the grooves. On the top surface of the ridge where the current blocking layer is not formed, an upper electrode is formed. On the bottom surface of the n-GaAs substrate, a lower electrode is formed, and thus the ridge type semiconductor laser is fabricated. This semiconductor laser is capable of emitting blue light with an oscillating wavelength of around 500 nm. The current blocking layer of the lamination of the SiO 2 and TiO 2 layers allows effective confinement of both light and carriers and a drastic decrease in the threshold current for a laser oscillation.
Inventors
- 👤 Yasuhito Takahashi
- 👤 Ayumu Tsujimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:08
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/30; H01S5/32; H01S5/327; H01S5/20; H01S5/22; H01S2304/00; H01S2304/04; H01S5/2205; H01S5/2214; H01S5/2222; H01S5/2227; H01S5/223; H01S5/2231
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
151 words
A II-VI compound semiconductor laser, comprising: a semiconductor substrate; a semiconductor multilayer structure formed on the semiconductor substrate, the semiconductor multilayer structure including a lower cladding layer, an upper cladding layer and an active layer interposed between the lower and upper cladding layers; an upper electrode formed on the semiconductor multilayer structure; and a lower electrode formed on a bottom surface of the semiconductor substrate, wherein the semiconductor multilayer structure comprises a striped ridge portion, side surfaces of the striped ridge portions being covered by a current blocking layer which confines current flowing between the upper and lower electrodes into the striped ridge portion, and the current blocking layer includes a first insulating material and a second insulating material, the first insulating material having a smaller refractive index than that of the upper cladding layer, the second insulating material having a larger refractive index than that of the upper cladding layer.
Claim 2
Dependent Claim
151 words
A II-VI compound semiconductor laser, comprising: a semiconductor substrate; a semiconductor multilayer structure formed on the semiconductor substrate, the semiconductor multilayer structure including a lower cladding layer, an upper cladding layer and an active layer interposed between the lower and upper cladding layers; an upper electrode formed on the semiconductor multilayer structure; and a lower electrode formed on a bottom surface of the semiconductor substrate, wherein the semiconductor multilayer structure comprises a striped ridge portion, side surfaces of the striped ridge portions being covered by a current blocking layer which confines current flowing between the upper and lower electrodes into the striped ridge portion, and the current blocking layer includes a first insulating material and a second insulating material, the first insulating material having a smaller refractive index than that of the upper cladding layer, the second insulating material having a larger refractive index than that of the upper cladding layer.
Claim 3
Dependent Claim
33 words
A semiconductor laser according to claim 1, wherein the current blocking layer further includes other insulating material having a different refractive index from those of either of the first and second insulating materials.
Claim 4
Dependent Claim
27 words
A semiconductor laser according to claim 1, wherein the current blocking layer is formed by a mixture of the first insulating material and the second insulating material.
Claim 5
Dependent Claim
37 words
A semiconductor laser according to claim 1, wherein the current blocking layer is formed by laminating a first insulating layer made of the first insulating material and a second insulating layer made of the second insulating material.
Claim 6
Dependent Claim
29 words
A semiconductor laser according to claim 4, wherein a laminated number of at least one of the first insulating layer and the second insulating layer is two or more.
Claim 7
Dependent Claim
44 words
A semiconductor laser according to claim 1, wherein the first insulating material is a material selected from a group consisting of SiO 2 , AlN, Al 2 O 3 and Si 3 N 4 , and the second insulating material is TiO 2 .
Claim 8
Dependent Claim
82 words
A semiconductor laser according to claim 1, wherein the semiconductor multilayer structure comprises flat portions in both right-hand and left-hand regions of the striped ridge portions, a level of the flat portions being substantially equal to a level of the striped ridge portion, and grooves are formed between the respective flat portions and the striped ridge portion, a bottom level of the grooves being located at a higher level than the active layer, the grooves being buried with the current blocking layer.
Claim 9
Dependent Claim
26 words
A semiconductor laser according to claim 4, wherein the current blocking layer further comprises a light absorbing layer which absorbs light emitted from the active layer.
Claim 10
Dependent Claim
19 words
A semiconductor laser according to claim 8, wherein the light absorbing layer is formed of a thin metal film.
Claim 11
Dependent Claim
45 words
A semiconductor laser according to claim 1, wherein the semiconductor substrate is formed of GaAs, the active layer is formed of a material selected from a group consisting of ZnSe, ZnSSe, ZnCdS and ZnCdSe, and the upper and lower cladding layers are formed of ZnMgSSe.
Claim 12
Dependent Claim
56 words
A semiconductor laser according to claim 10, wherein the semiconductor multilayer structure further comprises: a lower light guiding layer interposed between the lower cladding layer and the active layer; and an upper light guiding layer interposed between the upper cladding layer and an active layer, the upper and lower light guiding layers being formed of ZnSSe.
Claim 13
Independent Claim
169 words
A method for fabricating a II-VI compound semiconductor laser, comprising the steps of: (a) forming a semiconductor multilayer structure on a semiconductor substrate, the semiconductor multilayer structure including a lower cladding layer, an upper cladding layer and an active layer interposed between the lower and upper cladding layers; (b) forming an upper electrode on the semiconductor multilayer structure; (c) forming a lower electrode on a bottom surface of the semiconductor substrate; (d) forming a striped ridge portion by etching away a portion of the semiconductor multilayer structure in a striped pattern; and (e) covering side surfaces of the striped ridge portions with a current blocking layer which confines a current flowing between the upper and lower electrodes into the striped ridge portion, wherein the current blocking layer includes a first insulating material and a second insulating material, the first insulating material having a smaller refractive index than that of the upper cladding layer, the second insulating material having a larger refractive index than that of the upper cladding layer.
Claim 14
Independent Claim
169 words
A method for fabricating a II-VI compound semiconductor laser, comprising the steps of: (a) forming a semiconductor multilayer structure on a semiconductor substrate, the semiconductor multilayer structure including a lower cladding layer, an upper cladding layer and an active layer interposed between the lower and upper cladding layers; (b) forming an upper electrode on the semiconductor multilayer structure; (c) forming a lower electrode on a bottom surface of the semiconductor substrate; (d) forming a striped ridge portion by etching away a portion of the semiconductor multilayer structure in a striped pattern; and (e) covering side surfaces of the striped ridge portions with a current blocking layer which confines a current flowing between the upper and lower electrodes into the striped ridge portion, wherein the current blocking layer includes a first insulating material and a second insulating material, the first insulating material having a smaller refractive index than that of the upper cladding layer, the second insulating material having a larger refractive index than that of the upper cladding layer.
Claim 15
Dependent Claim
37 words
A method for fabricating a semiconductor laser according to claim 12, wherein the current blocking layer further includes other insulating material having a different refractive index from those of either of the first and second insulating materials.
Claim 16
Dependent Claim
31 words
A method for fabricating a semiconductor laser according to claim 12, wherein the current blocking layer is formed of a mixture of the first insulating material and the second insulating material.
Claim 17
Dependent Claim
41 words
A method for fabricating a semiconductor laser according to claim 12, wherein the current blocking layer is formed by laminating a first insulating layer made of the first insulating material and a second insulating layer made of the second insulating material.
Claim 18
Dependent Claim
33 words
A method for fabricating a semiconductor laser according to claim 15, wherein a laminated number of at least one of the first insulating layer and the second insulating layer is two or more.
Claim 19
Dependent Claim
48 words
A method for fabricating a semiconductor laser according to claim 12, wherein the first insulating material is a material selected from a group consisting of SiO 2 , AlN, Al 2 O 3 and Si 3 N 4 , and the second insulating material is TiO 2 .
Claim 20
Dependent Claim
94 words
A method for fabricating a semiconductor laser according to claim 12, wherein the striped ridge portions are formed such that the semiconductor multilayer structure comprises flat portions in both right-hand and left-hand regions of the striped ridge portions, a level of the flat portions being substantially equal to a level of the striped ridge portion, and grooves are formed between the respective flat portions and the striped ridge portion, a bottom level of the grooves being located at a higher level than the active layer, the grooves being buried with the current blocking layer.
Claim 21
Dependent Claim
26 words
A method for fabricating a semiconductor laser according to claim 18, wherein the grooves in the semiconductor multilayer structure are buried by the current blocking layer.
Claim 22
Dependent Claim
37 words
A method for fabricating a semiconductor laser according to claim 12, further comprising the step of forming a light absorbing layer in the current blocking layer, the light absorbing layer absorbing light emitted from the active layer.
Claim 23
Dependent Claim
23 words
A method for fabricating a semiconductor laser according to claim 20, wherein the light absorbing layer is formed by a thin metal film.
Claim 24
Dependent Claim
49 words
A method for fabricating a semiconductor laser according to claim 12, wherein the semiconductor substrate is formed of GaAs, the active layer is formed of a material selected from a group consisting of ZnSe, ZnSSe, ZnCdS and ZnCdSe, and the upper and lower cladding layers are formed of ZnMgSSe.
Claim 25
Dependent Claim
60 words
A method for forming a semiconductor laser according to claim 22, further comprising the steps of: forming a lower light guiding layer interposed between the lower cladding layer end the active layer; and forming an upper light guiding layer interposed between the upper cladding layer and an active layer, the upper and lower light guiding layers being formed by ZnSSe.
Claim 26
Dependent Claim
34 words
A method for forming a semiconductor laser according to claim 12, wherein in step (d), an etching solution of a mixture of potassium dichromate and sulfuric acid mixed at a predetermined proportion is used.
Claim 27
Dependent Claim
37 words
A method for fabricating a semiconductor laser according to claim 24, wherein the predetermined proportion is a proportion of the potassium dichromate and the sulfuric acid 3:2, and an etching temperature is set to be 40° C.
Claim 28
Dependent Claim
42 words
A method for fabricating a semiconductor laser according to claim 12, wherein in step (e), the current blocking layer is formed by a photo CVD method which utilizes an introduction of predetermined gases into a reactor and an irradiation by UV rays.
Claim 29
Dependent Claim
45 words
A method for fabricating a semiconductor laser according to claim 26, wherein the first insulating material included in the current blocking layer is SiO 2 the first insulating material being formed by the photo CVD method with silane and O 2 as the predetermined gases.
Claim 30
Dependent Claim
48 words
A method for fabricating a semiconductor laser according to claim 26 wherein the second insulating material included in the current blocking layer is TiO 2 , the second insulating material being formed by the photo CVD method with TiCl 4 and H 2 O as the predetermined gases.
Claim 31
Dependent Claim
45 words
A method for fabricating a semiconductor laser according to claim 26, wherein the current blocking layer further comprises a thin metal layer, the thin metal layer being formed by the photo CVD method with an organic metal compound and H 2 as the predetermined gases.
References Cited (Backward Citations)
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