Patent EP0454476A2 successfully refreshed from Google Patents.
EP0454476A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Semiconductor laser having double heterostructure and method of producing the same
Assignee: Fujitsu Ltd
•
Filing: 1991-04-26
•
Granted: —
•
Expires: 2011-04-26
Abstract
Abstract A semiconductor laser includes a substrate (81, 101, 111) having a (100) face as its main surface, where the substrate has a stripe of a first mesa extending in a <110> direction of the substrate and including a (111)B face as its sloping surface, a buried layer (82, 92, 102, 112, 123-126) formed on the substrate excluding a top surface of the stripe of the first mesa so that the (111)B face of the stripe of the first mesa is covered a sloping surface part of the buried layer, where the top surface of the stripe of the first mesa is the (100) face of the substrate and forms a stripe of a second mesa together with the sloping surface of the buried layer and the stripe of the second mesa has a smaller inclination than the stripe of the first mesa, and a double heterostructure (83-85, 104-106, 115-118) made up of a plurality of semiconductor layers and formed on the stripe of the second mesa. The double heterostructure has a substantially trapezoidal cross section which is determined by the stripe of the second mesa.
Inventors
- 👤 Mami Sugano
- 👤 Akira Furuya
- 👤 Toshiyuki Tanahashi
- 👤 Makoto Kondo
- 👤 Chikashi Anayama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 10:23
CPC Classifications
B; B82; B82Y; B82Y20/00; H; H01; H01S; H01S5/00; H01S5/10; H01S5/16; H01S5/20; H01S5/22; H01S5/223; H01S5/2232; H01S5/30; H01S5/32; H01S5/323; H01S5/32308; H01S5/32325; H01S5/34; H01S5/343; H01S5/34326; H10; H10H; H10H20/00; H10H20/01; H10H20/011; H10H20/013; H01S5/1053; H01S5/1064; H01S5/2201; H01S5/2205; H01S5/2206; H01S5/2209; H01S5/221; H01S5/2234; H01S5/2235; H01S5/227; H01S5/2272; H01S5/3211; H01S5/3235; H01S5/32391
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
187 words
A semiconductor laser characterized in that there are provided: a substrate (81, 101, 111) having a (100) face as its main surface, said substrate having a stripe of a first mesa extending in a <110> direction of the substrate and including a (111)B face as its sloping surface; a buried layer (82, 92, 102, 112, 123-126) formed on said substrate excluding a top surface of the stripe of the first mesa so that the (111)B face of the stripe of the first mesa is covered a sloping surface part of said buried layer, said top surface of the stripe of the first mesa being the (100) face of said substrate and forming a stripe of a second mesa together with the sloping surface of said buried layer, said stripe of the second mesa having a smaller inclination than said stripe of the first mesa; and a double heterostructure (83-85, 104-106, 115-118) made up of a plurality of semiconductor layers and formed on the stripe of the second mesa; said double heterostructure having a substantially trapezoidal cross section which is determined by said stripe of the second mesa.
Claim 2
Dependent Claim
23 words
The semiconductor laser as claimed in claim 1, characterized in that said buried layer (92, 102, 112, 123-126) forms a current confinement part.
Claim 3
Dependent Claim
59 words
The semiconductor laser as claimed in claim 1 or 2, characterized in that said buried layer (92, 102, 112, 123-126) is made of a material selected from a group consisting of a semiconductor of a conductor type opposite to that of a semiconductor forming said substrate and a semiconductor having a high resistance compared to that of said substrate.
Claim 4
Dependent Claim
25 words
The semiconductor laser as claimed in any of claims 1 to 3, characterized in that said substrate (101, 111) is made of a p-type semiconductor.
Claim 5
Dependent Claim
115 words
The semiconductor laser as claimed in any of claims 1 to 4, characterized in that said substrate (81, 101, 111) is made of GaAs, and said double heterostructure (83-85, 104-106, 115-118) includes a first cladding layer (83, 104, 115), an active layer (84, 105, 116) formed on the first cladding layer and a second cladding layer (85, 106, 117, 118) formed on the active layer, said active layer being made of one of InGaP and AlGaInP, said first and second cladding layers being both made of one of AlGaInP and AlInP but of mutually opposite conductor types, said first and second cladding layers having an energy band gap greater than that of said active layer.
Claim 6
Dependent Claim
87 words
The semiconductor laser as claimed in claim 5, characterized in that said substrate (101, 111) is made of p-type GaAs, and said semiconductor laser further comprises a first p-type buffer layer (103, 114) interposed between said p-type GaAs substrate and said first cladding layer (104, 115), said first p-type buffer layer being made of a material selected from a group consisting of InGaP, AlGaInP and AlGaAs and having an intermediate energy band gap which falls between energy band gaps of said first cladding layer and said substrate.
Claim 7
Dependent Claim
49 words
The semiconductor laser as claimed in claim 6, characterized in that there is further provided a second p-type buffer layer (110, 113) which is interposed between said p-type GaAs substrate (101, 111) and said first p-type buffer layer (103, 114), said second p-type buffer layer being made of GaAs.
Claim 8
Dependent Claim
44 words
The semiconductor laser as claimed in any of claims 5 to 7, characterized in that said second cladding layer (117, 118) is made of n-type AlGaInP and includes a mole fraction of Al which is smaller than that of said first cladding layer (115).
Claim 9
Dependent Claim
59 words
The semiconductor laser as claimed in claim 6, characterized in that there is further provided a p-type buffer layer (122) which is formed only on the (100) face which is the top surface of the stripe of the first mesa, said p-type buffer layer being made of a material selected from a group consisting of InGaP, AlGaInP and AlGaAs.
Claim 10
Dependent Claim
37 words
The semiconductor laser as claimed in any of claims 1 to 9, characterized in that said buried layer (82, 92, 102, 112, 123-126) is made of a material selected from a group consisting of GaAs and AlGaAs.
Claim 11
Dependent Claim
49 words
The semiconductor laser as claimed in any of claims 1 to 10, characterized in that said buried layer (124-126) includes a layer which is made of a material having a energy band gap which is sufficiently wide such that a potential wall for blocking injection minority carriers is generated.
Claim 12
Dependent Claim
74 words
The semiconductor laser as claimed in any of claims 1 to 3, characterized in that said substrate (101, 111) is made of p-type InP, and said double heterostructure (104-106, 115-118) includes a first cladding layer (104, 115), an active layer (105, 116) formed on the first cladding layer and a second cladding layer (106, 117, 118) formed on the active layer, said first and second cladding layers being made of mutually opposite conductor types.
Claim 13
Dependent Claim
44 words
The semiconductor laser as claimed in claim 12, characterized in that said active layer (105, 116) is made of InGaAsP, said first cladding layer (104, 115) is made of p-type InP, and said second cladding layer (106, 117, 118) is made of n-type InP.
Claim 14
Dependent Claim
33 words
The semiconductor laser as claimed in claim 13, characterized in that said buried layer (102, 112, 123-126) is made of a material selected from a group consisting of n-type InGaAs and n-type AlInAs.
Claim 15
Dependent Claim
44 words
The semiconductor laser as claimed in claim 12, characterized in that said active layer (105, 116) is made of InGaAs, said first cladding layer (104, 115) is made of p-type AlInAs, and said second cladding layer (106, 117, 118) is made of n-type AlInAs.
Claim 16
Dependent Claim
33 words
The semiconductor laser as claimed in claim 15, characterized in that said buried layer (102, 112, 123-126) is made of a material selected from a group consisting of n-type InGaAs and n-type AlInAs.
Claim 17
Dependent Claim
39 words
The semiconductor laser as claimed in claim 15 or 16, characterized in that there is further provided a p-type InP buffer layer (103, 114) interposed between said p-type InP substrate (101, 111) and said first cladding layer (104, 115).
Claim 18
Dependent Claim
54 words
The semiconductor laser as claimed in any of claims 1 to 17, characterized in that said stripe of the first mesa includes a tapered part (101C) where a width along the <1 1 0> direction of the sloping surface which is approximately the (111)B face decreases towards an edge surface of the semiconductor laser.
Claim 19
Dependent Claim
40 words
The semiconductor laser as claimed in claim 18, characterized in that said stripe of the first mesa includes a prism shaped part (101E) which does not have the (100) face and terminates at the edge surface of the semiconductor laser.
Claim 20
Dependent Claim
40 words
The semiconductor laser as claimed in claim 19, characterized in that said prism shaped part (101E) has a height which is lower than a height of the (100) face at the type surface of the stripe of the first mesa.
Claim 21
Dependent Claim
35 words
The semiconductor laser as claimed in any of claims 1 to 20, characterized in that said buried layer (82, 92, 102, 112, 123-126) completely covers the (111)B face of the stripe of the first mesa.
Claim 22
Independent Claim
253 words
A method of producing a semiconductor laser characterized by the steps of: (a) patterning a dielectric layer (91) which is formed on a (100) face of a substrate (81, 101, 111) into a stripe; (b) forming a stripe of a first mesa by making a mesa etching of the substrate using the stripe of the dielectric layer as a mask, said stripe of the first mesa including a (111)B face as its sloping surface; (c) removing eaves of the dielectric layer which is used as the mask in said step (b) by an etching; (d) forming a buried layer (82, 92, 102, 112, 123-126) by a metal organic vapor phase epitaxy (MOVPE) using the remaining dielectric layer as a mask so that the buried layer is formed on said substrate excluding a top surface of the stripe of the first mesa and the (111)B face of the stripe of the first mesa is covered a sloping surface part of said buried layer, said top surface of the stripe of the first mesa being the (100) face of the substrate and forming a stripe of a second mesa together with the sloping surface of said buried layer, said stripe of the second mesa having a smaller inclination than said stripe of the first mesa; (e) removing the dielectric layer by an etching; and (f) forming a double heterostructure (83-85, 104-106, 115-118) made up of a plurality of semiconductor layers on the stripe of the second mesa by a metal organic vapor phase epitaxy (MOVPE).
Claim 23
Dependent Claim
34 words
The method of producing the semiconductor laser as claimed in claim 22, characterized in that said step (c) uses am etchant which etches both the dielectric layer (91) and the substrate (81, 101, 111).
Claim 24
Dependent Claim
38 words
The method of producing the semiconductor laser as claimed in claim 22 or 23, characterized in that said etchant has approximately the same etching rate with respect to the dielectric layer (91) and the substrate (81, 101, 111).
Claim 25
Independent Claim
47 words
The method of producing the semiconductor laser as claimed in any of claims 22 to 24, characterized in that there is further provided the step (g) of forming a buffer layer (103, 114) between the stripe of the second mesa and the double heterostructure (83-85, 104-106, 115-118).
Claim 26
Independent Claim
50 words
The method of producing the semiconductor laser as claimed in any of claims 22 to 25, characterized in that said step (a) patterns the dielectric layer (91) so that a width along the <1 1 0 > direction is tapered and decreases towards an edge surface of the semiconductor laser.
Claim 27
Dependent Claim
52 words
The method of producing the semiconductor laser as claimed in claim 26, characterized in that said step (c) removes the eaves so that the width of the stripe of the dielectric layer (91) along the <1 1 0> direction becomes zero in a vicinity of the edge surface of the semiconductor laser.
Claim 28
Independent Claim
42 words
The method of producing the semiconductor laser as claimed in any of claims 22 to 27, characterized in that said step (f) forms each of the semiconductor layers (83-85, 104-106, 115-118) at a growth temperature in a range of 710 to 800°C.
Claim 29
Independent Claim
60 words
The method of producing the semiconductor laser as claimed in any of claims 22 to 28, characterized in that there is further provided the step (g) of removing a part of the stripe of the first mesa by an additional etching prior to said step (c) so that eaves of a predetermined length is formed by the dielectric layer (91).
Claim 30
Dependent Claim
49 words
The method of producing the semiconductor laser as claimed in claim 29, characterized in that said step (d) forms the buried layer (82, 92, 102, 112, 123-126) so that the buried layer completely covers the (111)B face at the sloping surface of of the stripe of the first mesa.
Claim 31
Dependent Claim
47 words
The method of producing the semiconductor laser as claimed in claim 22, characterized in that the substrate (81, 101, 111) is made of GaAs, and the buried layer (82, 92, 102, 112, 123-126) is made of a material selected from a group consisting of GaAs and AlGaAs.
Claim 32
Dependent Claim
47 words
The method of producing the semiconductor laser as claimed in claim 31, characterized in that the buried layer (102, 112, 123-126) is of a conductor type opposite to that of the substrate (101, 111) or has a resistance which is high compared to that of the substrate.
Claim 33
Dependent Claim
105 words
The method of producing the semiconductor laser as claimed in claim 31 or 32, characterized in that the double heterostructure (83-85, 104, 106, 115-118) includes an active layer (84, 105, 116) and first and second cladding layers (83, 85, 104, 106, 115, 117, 118) which sandwich the active layer, said active layer is made of a material selected from a group consisting of InGaP and AlGaInP, and said first and second cladding layers are made of a material selected from a group consisting of AlGaInP and AlInP of mutually opposite conductor types and having an energy band gap greater than that of the active layer.
Claim 34
Dependent Claim
43 words
The method of producing the semiconductor laser as claimed in claim 33, characterized in that said step (f) forms the first and second cladding layers (83, 85, 104, 106, 115, 117, 118) at a growth temperature in a range of 710 to 800°C.
Claim 35
Independent Claim
47 words
The method of producing the semiconductor laser as claimed in any of claims 22 to 34, characterized in that the substrate (81, 101, 111) is made of GaAs, and said step (a) forms the dielectric layer (91) on the (100) face of the substrate by a sputtering.
Claim 36
Independent Claim
60 words
The method of producing the semiconductor laser as claimed in any of claims 22 to 35, characterized in that the substrate (81, 101, 111) is made of GaAs, and said step (b) forms the stripe of the first mesa using as an etchant a mixed solution of H₂SO₄, H₂O₂ and H₂O, said etchant in use being heated to approximately 50°C.
Claim 37
Dependent Claim
47 words
The method of producing the semiconductor laser as claimed in claim 22, characterized in that the substrate (81, 101, 111) is made of InP, and the buried layer (82, 92, 102, 112, 123-126) is made of a material selected from a group consisting of InGaAs and AlInAs.
Claim 38
Dependent Claim
36 words
The method of producing the semiconductor laser as claimed in claim 37, characterized in that the buried layer (92, 102, 112, 123-126) is of a conductor type opposite to that of the substrate (81, 101, 111).
Claim 39
Dependent Claim
103 words
The method of producing the semiconductor laser as claimed in claim 37, characterized in that the double heterostructure (83-85, 104-106, 115-118) includes an active layer (84, 105, 116) and first and second cladding layers (83, 85, 104, 106, 115, 117, 118) which sandwich the active layer, said active layer is made of a material selected from a group consisting of InGaAs and AlGaAsP, and said first and second cladding layers are made of a material selected from a group consisting of InGaAsP, InP and AlInAs of mutually opposite conductor types and having an energy band gap greater than that of the active layer.
Claim 40
Independent Claim
283 words
A method of producing a semiconductor laser characterized by the steps of: (a) patterning a dielectric layer (91) which is formed on a main surface of a substrate (81, 101, 111) into a stripe; (b) forming a stripe of a first mesa by making a mesa etching of the substrate using the stripe of the dielectric layer as a mask, said stripe of the first mesa having a top surface and a sloping surface; (c) removing eaves of the dielectric layer which is used as the mask in said step (b) by an etching; (d) forming a buried layer (82, 92, 102, 112, 123-126) by a metal organic vapor phase epitaxy (MOVPE) using the remaining dielectric layer as a mask so that the buried layer is formed on said substrate excluding the top surface of the stripe of the first mesa and the sloping surface of the stripe of the first mesa is covered a sloping surface part of said buried layer, said step (d) being carried out under conditions such that the growth rate of the buried layer on the sloping surface of the stripe of the first mesa is slower than that at other parts of the substrate, said top surface of the stripe of the first mesa forming a stripe of a second mesa together with the sloping surface of said buried layer, said stripe of the second mesa having a smaller inclination than said stripe of the first mesa; (e) removing the dielectric layer by an etching; and (f) forming a double heterostructure (83-85, 104-106, 115-118) made up of a plurality of semiconductor layers on the stripe of the second mesa by a metal organic vapor phase epitaxy (MOVPE).
Claim 41
Independent Claim
248 words
A method of producing a semiconductor laser characterized by the steps of: (a) forming on a substrate (201, 205) a mask (202, 206) having a stripe opening (202A, 206A) which extends in a <110> direction of the substrate, said substrate being made of a compound semiconductor of a first conductor type; (b) forming a stripe projection part (203, 207) on the substrate which is exposed within the stripe opening by a metal organic vapor phase epitaxy (MOVPE), said stripe projection part having one of a triangular and a trapezoidal cross section with a (111)B face as its sloping surface and being made of a compound semiconductor; (c) forming a blocking layer (204, 211) on the substrate by a metal organic vapor phase epitaxy (MOVPE) so as to cover the (111)B face under a predetermined condition such that a growth rate of the blocking layer on the sloping surface of the stripe projection part is slower than that at other parts of the substrate; and (d) forming a stripe part (213A) which acts as a wave guide and a bent part (213B) provided on both sides of the stripe part for trapping light by successively growing a first cladding layer (212), an active layer (213) and a second cladding layer (214), said stripe part being formed above said stripe projection part, said bent part having a (311)B face as its sloping surface, said first and second cladding layers being respectively made of mutually opposite first and second conductor types.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.