EP0210616A2
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Semiconductor laser
Assignee: Hitachi Ltd
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Filing: 1986-07-24
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Granted: —
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Expires: 2006-07-24
Abstract
Abstract In a semiconductor laser, a multiple quantum well type active layer consisting of barrier layers (15,16,17) and active layers of well layers (11), each of which has a thickness less than the de Broglie wavelength of electons, is doped with an impurity, and the impurity density is made higher in the barrier layer (15, 16, 17) than in the well layer (11). Where the multiple quantum well active layer is held between p-type and n-type cladding layers (14,13), the well layer (11) is undoped, the part (15) of the barrier layer lying in contact with the well layer (11) is undoped, and the other part (17) of the barrier layer close to the p-type cladding layer (14) is put into the n-conductivity type while that (16) of the barrier layer close to the n-type cladding layer (13) is put into the p-conductivity type.
Inventors
- 👤 Naoki Chinone
- 👤 Kazuhisa Uomi
- 👤 Tadashi Fukuzawa
- 👤 Hideaki Matsueda
- 👤 Takashi Kajimura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 10:08
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/30; H01S5/34; B; B82; B82Y; B82Y20/00; H01S5/20; H01S5/22; H01S5/227; H01S5/2275; H01S5/305; H01S5/3086; H01S5/309; H01S5/3407
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
105 words
A semiconductor laser wherein semiconductor layers are formed on a semiconductor substrate (1; 18), the semiconductor layers including at least a cladding layer (2; 13, 14), and one or more active layers (3) stacked with one or more barrier layers (4) or a multiple quantum well type active layer (20) in which a well layer (11) and a barrier layer (15, 16, 17) are stacked on each other, and wherein the thickness of the or each active layer (3; 20) is smaller than a wave packet of free electrons within a crystal, characterized in that said active layer (3; 20) is doped with an impurity.
Claim 2
Dependent Claim
105 words
A semiconductor laser wherein semiconductor layers are formed on a semiconductor substrate (1; 18), the semiconductor layers including at least a cladding layer (2; 13, 14), and one or more active layers (3) stacked with one or more barrier layers (4) or a multiple quantum well type active layer (20) in which a well layer (11) and a barrier layer (15, 16, 17) are stacked on each other, and wherein the thickness of the or each active layer (3; 20) is smaller than a wave packet of free electrons within a crystal, characterized in that said active layer (3; 20) is doped with an impurity.
Claim 3
Dependent Claim
12 words
The semiconductor laser of Claim 1, wherein said impurity is an acceptor.
Claim 4
Dependent Claim
41 words
The semiconductor laser of Claim 1 or 2, wherein in doping said multiple quantum well type active layer (20) with said impurity, the impurity density of said barrier layer (16, 17) is made higher than that of said well layer (11).
Claim 5
Dependent Claim
133 words
A semiconductor laser wherein a plurality of semiconductor layers formed on a semiconductor substrate (18) include a multiple quantum well active layer (20) in which well layers (11) each having a thickness less than the de Broglie wavelength of electrons are stacked alternately with barrier layers (15, 16, 17) having a band gap greater than that of the well layer (11), and p-type-and n-type cladding layers (13, 14) which are formed so as to hold the multiple quantum well active layer (20) therebetween and each of which has a band gap greater than that of the well layer (11), characterized in that the conductivity types of the respective layers which constitute said multiple quantum well active layer (20) are spatially different in a direction of stacking said multiple quantum well active layer (20).
Claim 6
Dependent Claim
133 words
A semiconductor laser wherein a plurality of semiconductor layers formed on a semiconductor substrate (18) include a multiple quantum well active layer (20) in which well layers (11) each having a thickness less than the de Broglie wavelength of electrons are stacked alternately with barrier layers (15, 16, 17) having a band gap greater than that of the well layer (11), and p-type-and n-type cladding layers (13, 14) which are formed so as to hold the multiple quantum well active layer (20) therebetween and each of which has a band gap greater than that of the well layer (11), characterized in that the conductivity types of the respective layers which constitute said multiple quantum well active layer (20) are spatially different in a direction of stacking said multiple quantum well active layer (20).
Claim 7
Dependent Claim
57 words
The semiconductor laser of Claim 4, wherein in said multiple quantum well active layer (20), at least one set of well and barrier layers (11, 17) which are continuous in adjacency to said p-type cladding layer (14) have the n-conductivity type, and the other region of said multiple quantum well active layer (20) has the p-conductivity type.
Claim 8
Dependent Claim
65 words
The semiconductor laser of Claim 4, wherein in said multiple quantum well active layer (20), at least one barrier layer (17) which is continuous and adjacent to said p-type cladding layer (14) has the n-conductivity type, the barrier layers (16) in the other region of said multiple quantum well active layer (20) have the p-conductivity type, and all of said well layers (11) are undoped.
Claim 9
Dependent Claim
109 words
The semiconductor laser of Claim 4, wherein in said multiple quantum well active layer (20), at least one barrier layer (17) which is continuous and adjacent to said p-type cladding layer (14) has the n-conductivity type, but at least one atom layer from an interface at which it lies in contact with the well layer (11) is undoped; the barrier layers (16) in the other region of said multiple quantum well active layer (20) have the p-conductivity type, but at least one atom layer from an interface at which it lies in contact with the well layer (11) is undoped; and all of said well layers (11) are undoped.
Claim 10
Dependent Claim
49 words
The semiconductor laser of Claim 4, wherein said barrier layer (15) is undoped in at least one atom layer from an interface at which it lies in contact with said well layer (11) and has the p-conductivity type in the other region, and said well layer (11) is undoped.
Claim 11
Dependent Claim
38 words
The semiconductor laser of any of Claims 4 - 8, wherein the p-type impurity is Be or Mg while the n-type impurity is Se or Si, and the impurity concentration is at least 5 x 10 17 (cm).
References Cited (Backward Citations)
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