EP0259026A2
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Double-heterostructure semiconductor laser with mesa stripe waveguide
Assignee: Toshiba Corp
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Filing: 1987-08-07
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Granted: —
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Expires: 2007-08-07
Abstract
Abstract Disclosed herein is a double-heterostructure semiconductor laser (10) which emits a laser beam in a visible light range at ambient temperature. An active layer (20) serving as a light emission layer is sandwiched between first and second cladding layers (18, 26). The first and second cladding layer (18) comprises an n type InAℓP, while the second cladding layer (26) comprises a p type InAℓP and has a mesa stripe shape having slanted side surfaces (26a, 26b) so as to define a light waveguide channel of the semiconductor laser. Current-blocking layers (34-1, 34-2) are formed to cover the slanted side surfaces (26a, 26b) of the second cladding layer (26). The current-blocking layers (34-1), 34-2) comprise GaAs which is a III-V group compound semiconductor different from the III-V group compound semiconductor (i.e., InAℓP) comprising in the second cladding layer (26). The composition ratio of aluminum in the second cladding layer (26) is set not to be less than 0.4, whereby a Shottky barrier serving to inhibit or suppress a current leak in the light waveguide channel of the semiconductor laser (10) is formed between the second cladding layer (26) and the current-blocking layers (34-1, 34-2).
Inventors
- 👤 Yasuo C/O Patent Division Ohba
- 👤 Miyoko C/O Patent Division Watanabe
- 👤 Hideto C/O Patent Division Sugawara
- 👤 Masayuki C/O Patent Division Ishikawa
- 👤 Yukio C/O Patent Division Watanabe
- 👤 Motoyuki C/O Patent Division Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 18:40
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/20; H01S5/22; H01S5/223; H01S5/2231; H01S5/30; H01S5/32; H01S5/323; H01S5/32308; H01S5/32325
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
191 words
A semiconductor laser (10, 60) for emitting a laser beam in a visible light range, comprising a semiconductive substrate (12) of a first conductivity type comprising a III-V group compound semiconductor, a first semiconductive cladding layer (18) of said first conductivity type disposed on said substrate, and an active layer (20) disposed on said first cladding layer (18) and formed by a semiconductor film, characterized in that said laser further comprises: a second semiconductive cladding layer (26, 62) of a second conductivity type disposed on said active layer (20) to provide a double-heterostructure junction, said second cladding layer (26, 62) having a mesa stripe shape having slanted side surfaces and defining a light waveguide channel of said semiconductor laser, and said second cladding layer (26, 62) comprising a compound semiconductor containing a first III-group element and a first V-group element; and a semiconductive current-blocking layer (34, 64) formed to cover said slanted side surfaces of said second cladding layer (26, 62), and comprising a compound semiconductor which is different from said compound semiconductor of said second cladding layer (26, 26) and contains a second III-group element and a second V-group element.
Claim 2
Dependent Claim
191 words
A semiconductor laser (10, 60) for emitting a laser beam in a visible light range, comprising a semiconductive substrate (12) of a first conductivity type comprising a III-V group compound semiconductor, a first semiconductive cladding layer (18) of said first conductivity type disposed on said substrate, and an active layer (20) disposed on said first cladding layer (18) and formed by a semiconductor film, characterized in that said laser further comprises: a second semiconductive cladding layer (26, 62) of a second conductivity type disposed on said active layer (20) to provide a double-heterostructure junction, said second cladding layer (26, 62) having a mesa stripe shape having slanted side surfaces and defining a light waveguide channel of said semiconductor laser, and said second cladding layer (26, 62) comprising a compound semiconductor containing a first III-group element and a first V-group element; and a semiconductive current-blocking layer (34, 64) formed to cover said slanted side surfaces of said second cladding layer (26, 62), and comprising a compound semiconductor which is different from said compound semiconductor of said second cladding layer (26, 26) and contains a second III-group element and a second V-group element.
Claim 3
Dependent Claim
37 words
The semiconductor laser according to claim 1, characterized in that said second cladding layer (26, 62) further contains aluminum, and the composition ratio of aluminum in said second cladding layer (26, 62) is not less than 0.4
Claim 4
Dependent Claim
54 words
The semiconductor laser according to claim 2, characterized in that said first III-group element and said first V-group element which constitute said second cladding layer (26, 62) are indium and phosphorus, respectively, and said second III-group element and said second V-group element which constitute said current-blocking layer (34, 64) are gallium and arsenic, respectively.
Claim 5
Dependent Claim
29 words
The semiconductor laser according to claim 3, characterized in that said current-blocking layer (34, 64) has a carrier concentration greater than that of said second cladding layer (26, 62).
Claim 6
Dependent Claim
45 words
The semiconductor laser according to claim 4, characterized in that said carrier concentration of said second cladding layer (26, 62) is greater than 7 × 10¹⁷ cm⁻³ and said carrier concentration of said current blocking layer (34, 64) is greater than 1 × 10¹⁸ cm⁻³.
Claim 7
Dependent Claim
68 words
The semiconductor laser according to claim 5, characterized in that said composition ratio of aluminum is said second cladding layer (26, 62) is set to range between 0.4 and 0.5, whereby a Shottky barrier serving to inhibit or suppress a current leak in said light waveguide channel of said semiconductor laser (10, 60) is formed between said second cladding layer (26, 62) and said current-blocking layer (34, 64).
Claim 8
Dependent Claim
66 words
The semiconductor laser according to claim 5, characterized in that said composition of aluminum in said second cladding layer (26, 62) is set to range between 0.4 and 0.5, whereby said second cladding layer (26, 62) has a band gap of an indirect transitional type so that an increased band gap discontinuity exists between said second cladding layer (26, 62) and said current-blocking layer (34, 64).
Claim 9
Dependent Claim
26 words
The semiconductor laser according to claim 5, characterized in that said second cladding layer (26, 62)l and said current-blocking layer (34, 64) have different conductivity types.
Claim 10
Dependent Claim
27 words
The semiconductor laser according to claim 5, characterized in that said second cladding layer (26, 62) and said current-blocking layer (34, 64) have the same conductivity type.
Claim 11
Dependent Claim
194 words
A double-heterostructure semiconductor laser (10, 60), comprising a semiconductive substrate (12) of a first conductivity type comprising a III-V group compound semiconductor, a first semiconductive cladding layer (18) of said first conductivity type disposed on said semiconductive substrate, and an active layer (20) disposed on said first cladding layer and formed by a semiconductor film, said active layer serving as a light emission layer, characterized in that said laser further comprises a second semiconductive cladding layer (26, 62) of a second conductivity type disposed on said active layer (20) to have a mesa stripe shape having slanted side surfaces, thereby defining a light waveguide channel of said laser (10, 60), said second cladding layer (26, 62) comprising a compound semiconductor containing a first III-group element, a first V-group element and aluminum with a composition ratio of said aluminum in said second cladding layer (26, 62) being not less than 0.4; and a semiconductor layer (34, 64) formed to cover said slanted side surfaces of said second cladding layer (26, 62) and serving to perform a current-blocking function, said semiconductor layer comprising a compound semiconductor containing a second III-group element and a second V-group element.
Claim 12
Dependent Claim
194 words
A double-heterostructure semiconductor laser (10, 60), comprising a semiconductive substrate (12) of a first conductivity type comprising a III-V group compound semiconductor, a first semiconductive cladding layer (18) of said first conductivity type disposed on said semiconductive substrate, and an active layer (20) disposed on said first cladding layer and formed by a semiconductor film, said active layer serving as a light emission layer, characterized in that said laser further comprises a second semiconductive cladding layer (26, 62) of a second conductivity type disposed on said active layer (20) to have a mesa stripe shape having slanted side surfaces, thereby defining a light waveguide channel of said laser (10, 60), said second cladding layer (26, 62) comprising a compound semiconductor containing a first III-group element, a first V-group element and aluminum with a composition ratio of said aluminum in said second cladding layer (26, 62) being not less than 0.4; and a semiconductor layer (34, 64) formed to cover said slanted side surfaces of said second cladding layer (26, 62) and serving to perform a current-blocking function, said semiconductor layer comprising a compound semiconductor containing a second III-group element and a second V-group element.
Claim 13
Dependent Claim
30 words
The semiconductor laser according to claim 10, characterized in that said composition ratio of aluminum in said second cladding layer (26, 62) is set to range between 0.4 and 0.5.
Claim 14
Dependent Claim
54 words
The semiconductor laser according to claim 11, characterized in that said first III-group element and said first V-group element which constitute said second cladding layer (26, 62) are indium and phosphorus, respectively, and said second III-group element and said second V-group element which constitute said semiconductor layer (34, 64) are gallium and arsenic, respectively.
Claim 15
Dependent Claim
29 words
The semiconductor laser according to claim 12, characterized in that said semiconductor layer (34, 64) has a carrier concentration greater than that of said second cladding layer (26, 62).
Claim 16
Dependent Claim
43 words
The semiconductor laser according to claim 13, characterized in that said carrier concentration of said second cladding layer (26, 62) is greater than 7 × 10¹⁷ cm⁻³ said carrier concentration of said semiconductor layer (34, 64) is greater than 7 × 10¹⁸ cm⁻³.
Claim 17
Dependent Claim
26 words
The semiconductor laser according to claim 14, characterized in that said second cladding layer (26, 62) and said semiconductor layer (34, 64) have different conductivity types.
Claim 18
Dependent Claim
27 words
The semiconductor laser according to claim 14, characterized in that said second cladding layer (26, 62) and said semiconductor layer (34, 64) have a p conductivity type.
Claim 19
Dependent Claim
239 words
A double-heterostructure semiconductor laser (60) for emitting a laser beam in a visible light range at the ambient temperature, comprising a semiconductive substrate (12) of a first conductivity type comprising a III-V group compound semiconductor, a first semiconductive cladding layer (18) of said first conductivity type disposed on said substrate (12), and an active layer (20) disposed on said first cladding layer (18) and formed by a semiconductor film, said active layer (20) serving as a light emission layer, characterized in that said laser further comprises: a second semiconductive cladding layer (62) of a second conductivity type disposed on said active layer (20) to have a mesa stripe shape having slanted side surfaces, thereby defining a light waveguide channel of said laser, said second cladding layer (62) comprising a compound semiconductor containing a first III-group element, a first V-group element and aluminum with a composition ratio of said aluminum in said second cladding layer (62) being not less than 0.4; and a semiconductive contact layer (64) formed to cover said slanted side surfaces of said second cladding layer (62) and serving to perform a current-blocking function, said contact layer (64) comprising a compound semiconductor containing a second III-group element and a second V-group element, whereby a Shottky barrier serving to inhibit or suppress a current leak in said light waveguide channel of said semiconductor laser (60) is formed between said second cladding layer (62) and said contact layer (64).
Claim 20
Dependent Claim
239 words
A double-heterostructure semiconductor laser (60) for emitting a laser beam in a visible light range at the ambient temperature, comprising a semiconductive substrate (12) of a first conductivity type comprising a III-V group compound semiconductor, a first semiconductive cladding layer (18) of said first conductivity type disposed on said substrate (12), and an active layer (20) disposed on said first cladding layer (18) and formed by a semiconductor film, said active layer (20) serving as a light emission layer, characterized in that said laser further comprises: a second semiconductive cladding layer (62) of a second conductivity type disposed on said active layer (20) to have a mesa stripe shape having slanted side surfaces, thereby defining a light waveguide channel of said laser, said second cladding layer (62) comprising a compound semiconductor containing a first III-group element, a first V-group element and aluminum with a composition ratio of said aluminum in said second cladding layer (62) being not less than 0.4; and a semiconductive contact layer (64) formed to cover said slanted side surfaces of said second cladding layer (62) and serving to perform a current-blocking function, said contact layer (64) comprising a compound semiconductor containing a second III-group element and a second V-group element, whereby a Shottky barrier serving to inhibit or suppress a current leak in said light waveguide channel of said semiconductor laser (60) is formed between said second cladding layer (62) and said contact layer (64).
Claim 21
Dependent Claim
29 words
The semiconductor laser according to claim 17, characterized in that said composition ratio of aluminum in said second cladding layer (62) is set to range between 0.4 and 0.5.
Claim 22
Dependent Claim
52 words
The semiconductor laser according to claim 18, characterized in that said first III-group element and said first V-group element which constitute said second cladding layer (62) are indium and phosphorus, respectively, and said second III-group element and said second V-group element which constitute said contact layer (64) are gallium and arsenic, respectively.
Claim 23
Dependent Claim
27 words
The semiconductor laser according to claim 19, characterized in that said contact layer (64) has a carrier concentration greater than that of said second cladding layer (62).
Claim 24
Dependent Claim
42 words
The semiconductor laser according to claim 20, characterized in that said carrier concentration of said second cladding layer (62) is greater than 7 × 10¹⁷ cm⁻³ and said carrier concentration of said contact layer (64) is greater than 1 × 10¹⁸ cm⁻³.
Claim 25
Dependent Claim
24 words
The semiconductor laser according to claim 21, characterized in that said second cladding layer (62) and said contact layer (64) have a p-conductivity type.
Claim 26
Dependent Claim
68 words
The semiconductor laser according to claim 21, characterized by further comprising a compound semiconductor layer (30) provided between said second cladding layer (62) and said contact layer (64), said compound semiconductor layer (30) comprising plural types of III-group elements and a single V-group element, thereby suppressing a change in band gaps of said second cladding layer (62) and said contact layer (64) and reducing an electric resistance therebetween.
References Cited (Backward Citations)
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