Laser Devices Patents (Class 148/DIG95)
  • Patent number: 5266503
    Abstract: A surface emitting laser diode device is disclosed where an active layer is implanted with oxygen ions except for a small active region. The active region includes a pn junction for generating radiation in response to passage of electrical current therethrough. After the oxygen implantation, mirror layers are grown on top of the active layer to reflect light generated in the active region back into the active region to induce more radiation emission. Mirror layers are also provided underneath the active region for the same purpose. Contact layers are provided on the top and bottom of the structure just described so that when an electrical potential is applied between the two contacts, electrical current will flow between the contacts between the active region for generating radiation. The oxygen-implanted isolation region surrounds the active region in order to confine current flow to the active region.
    Type: Grant
    Filed: October 2, 1991
    Date of Patent: November 30, 1993
    Assignee: Hewlett-Packard Company
    Inventors: Shih-Yuan Wang, Michael R. T. Tan
  • Patent number: 5260231
    Abstract: A semiconductor laser device is disclosed which emits laser light from a facet. The semiconductor laser device comprises a multi-layered structure formed on a semiconductor substrate, the multi-layered structure having an AlGaAs active layer for laser oscillation, and a protective film formed on the facet, wherein a film containing sulfur is provided between the facet and the protective film.
    Type: Grant
    Filed: December 30, 1992
    Date of Patent: November 9, 1993
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hidenori Kawanishi, Taiji Morimoto, Shinji Kaneiwa, Hiroshi Hayashi, Nobuyuki Miyauchi, Seiki Yano, Mitsuhiro Matsumoto, Kazuaki Sasaki, Masaki Kondo, Takehiro Shiomoto, Saburo Yamamoto
  • Patent number: 5252513
    Abstract: The present invention is an apparatus and method for providing detection of a laser output on a semiconductor wafer. A laser cavity and a detection cavity are formed on a semiconductor wafer in parallel such that light emitted laterally from the laser cavity is detected by the detection cavity. The amount of light detected can then be transformed into data, which in turn can be used to control the output of the laser.
    Type: Grant
    Filed: June 12, 1991
    Date of Patent: October 12, 1993
    Assignee: Xerox Corporation
    Inventors: Thomas L. Paoli, G. A. N. Connell, Donald R. Scifres, Robert L. Thornton
  • Patent number: 5242856
    Abstract: In a method of manufacturing a semiconductor laser which includes a window structure at the periphery of an active layer. The width of the optical waveguide is determined by an etching, and the window structure is formed by an interdiffusion of atoms between a carrier confining layer and the active layer.
    Type: Grant
    Filed: October 1, 1990
    Date of Patent: September 7, 1993
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Haruki Kurihara, Hideo Tamura, Hirokazu Tanaka
  • Patent number: 5236864
    Abstract: A method of manufacturing a surface-emitting-type semiconductor laser device having a buried structure. A GaAlAs film is used as a mask layer in forming a GaAlAs/GaAs system burying part around a GaAlAs/GaAs system buried part. The mask layer can be formed continuously together with an active layer, a cladding layer and the like which constitute the buried part by means of a crystal growing apparatus for forming the buried part. When the system is etched, the GaAlAs film mask prevents the system buried part from becoming undercut so that the mask has better resistance to peeling during subsequent processing.
    Type: Grant
    Filed: May 12, 1992
    Date of Patent: August 17, 1993
    Assignees: Research Development Corporation of Japan, Tokyo Institute of Technology, Sanyo Electric Co., Ltd.
    Inventors: Kenichi Iga, Akira Ibaraki, Kenji Kawashima, Kotaro Furusawa, Toru Ishikawa
  • Patent number: 5227015
    Abstract: An n-InP buffer layer 102, an InGaAsP active layer 103, a p-InP cladding layer 104 and a p-InGaAsP surface protective layer 105 are successively epitaxially grown on an n-InP substrate 101 having a (100) plane as a main plane. An etching mask 106, an insulating film, is formed in a stripe in the <011> direction by photolithography and dry etching. Using a solution comprising a mixture of hydrochloric acid, oxygenated water and acetic acid, the n-InP buffer layer 102 is etched to a depth lower than the p-InP cladding layer 103, to form a mesa stripe 107. Next, the insulating film 106 is removed and the p-InGaAsP surface protective layer 105 is removed using a solution comprising a mixture of sulfuric acid and oxygenated water. Thereafter, InP current blocking layers 108 and 109 are selectively formed at the regions other than the mesa stripe 107 by the liquid-phase epitaxial growth. Thus, a buried heterostructure semiconductor laser is fabricated, having good laser characteristics and a high reliability.
    Type: Grant
    Filed: July 25, 1991
    Date of Patent: July 13, 1993
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kiyoshi Fujihara, Masato Ishino, Naoki Takenaka
  • Patent number: 5219785
    Abstract: A method using implantation to form a semiconductor laser or laser array with current blocking implants. A semiconductor material laser structure including layers of a first conductivity type, an active region and layers of a second conductivity type is formed. In a first embodiment, impurity ions of the second conductivity type are implanted into selected regions of a first conductivity type layer. The implanted ions form current blocking buried regions of the second conductivity type with current confining channels therebetween. Finally, the structure is thermally annealed. In a second embodiment, a disorder inducing impurity, which may be a saturable absorber, is diffused into selected portions of the layers of the first conductivity type through the active region. The diffusion converts side regions of those layers into the second conductivity type.
    Type: Grant
    Filed: July 25, 1990
    Date of Patent: June 15, 1993
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: David F. Welch, Donald R. Scifres, William Streifer
  • Patent number: 5213998
    Abstract: A method for producing an ohmic contact to a p-type ZnSe semiconductor body in a molecular beam epitaxy chamber. Zinc, thermally cracked Se.sub.2 and nitrogen are injected into the chamber. A ZnSe contact layer is grown by heating the semiconductor body to a temperature less than 250.degree. C., but high enough to promote crystalline growth of the layer doped with nitrogen to a net acceptor concentration of at least 1.times.10.sup.18 cm.sup.-3.
    Type: Grant
    Filed: May 15, 1991
    Date of Patent: May 25, 1993
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Jun Qiu, Hwa Cheng, Michael A. Haase, James M. DePuydt
  • Patent number: 5202285
    Abstract: A semiconductor laser includes a substrate 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 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 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.
    Type: Grant
    Filed: June 4, 1992
    Date of Patent: April 13, 1993
    Assignee: Fujitsu Limited
    Inventors: Mami Sugano, Akira Furuya, Toshiyuki Tanahashi, Makoto Kondo, Chikashi Anayama
  • Patent number: 5194400
    Abstract: A method for fabricating an AlGaInP-based visible light laser device by molecular beam epitaxy is described. In this method, a upper clad layer of (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P wherein x and y are, respectively, in the ranges of from 0.5 to 1 and from 0.47 to 0.53 is covered with a protective layer serving also as an etching prevenive layer so that a grooved-type structure using the (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P clad layer can be fabricated without involving degradation of the clad layer by contamination with oxygen, nitrogen and the like.
    Type: Grant
    Filed: November 29, 1991
    Date of Patent: March 16, 1993
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Akira Takamori, Ken Idota, Kiyoshi Uchiyama, Masato Nakajima
  • Patent number: 5185290
    Abstract: A method of selectively coating one of two spaced apart facets of respective light-emitting regions on the same surface of a semiconductor device formed in a semiconductor wafer includes forming at least one first groove in a wafer and forming at least one second groove in the wafer intersecting the first groove, exposing light-emitting region facets on a side wall surface of the second groove. A stream of an evaporated coating material is directed across an edge, formed by the intersection of a side wall surface of the second groove with the first groove, at an angle relative to the wafer surface so that the edge shadows one of the light-emitting region facets but not the other. After the coating process, the wafer is divided into individual devices that may include adjacent, differently coated light-emitting region facets. The invention avoids a mechanical mask alignment step by employing in the coating process first grooves that are self aligning relative to the light-emitting region facets.
    Type: Grant
    Filed: August 1, 1990
    Date of Patent: February 9, 1993
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshitaka Aoyagi, Kimio Shigihara
  • Patent number: 5185289
    Abstract: The process is particularly useful in the fabrication of GaAs quantum well (QW) laser diodes. Starting point is a ridge-patterned (100)-substrate (21), the crystal orientation of the sidewalls, e.g., (411A)-oriented, being different from that of the horizontal top. The sidewall facets thus have a lower Ga incorporation rate.In a molecular beam epitaxy (MBE) system, the lower AlGaAs cladding layer (22) is first grown, followed by the high-temperature growth of the active GaAs QW (23). Due to diffusion and desorption processes, the GaAs thickness at the sidewalls is smaller than on the horizontal top of the ridge. During a short growth interrupt, the GaAs completely desorbs from the sidewall facets. With the subsequent growth of the upper cladding layer (24), the QW becomes laterally embedded in higher bandgap material providing for lateral electric confinement.
    Type: Grant
    Filed: June 25, 1991
    Date of Patent: February 9, 1993
    Assignee: International Business Machines Corporation
    Inventors: Heinz P. Meier, Edward A. Van Gieson, Willi Walter
  • Patent number: 5182228
    Abstract: In a ridge waveguide-type semiconductor light-emitting device, a buried layer is composed of a high-resistance semiconductor material (e.g., amorphous silicon), thereby improving the heat-dissipating characteristic and prolonging lifetime. The buried layer is made higher than the top surface of the ridge, the top surface of the ridge is situated in the resulting recess, and an electrode is formed from the top surface of the ridge to the top surface of the surrounding buried layer to cover the entirety of these surfaces. Making the buried layer higher than the top of the ridge prevents an electrical short circuit for being caused by an electrically conductive bonding agent used in junction-down mounting.
    Type: Grant
    Filed: January 28, 1992
    Date of Patent: January 26, 1993
    Assignee: Omron Corporation
    Inventors: Hiroshi Sekii, Koichi Imanaka
  • Patent number: 5180685
    Abstract: There is provided a method for the production of a semiconductor laser device which emits laser light from an end facet thereof.
    Type: Grant
    Filed: April 2, 1991
    Date of Patent: January 19, 1993
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Osamu Yamamoto, Hidenori Kawanishi
  • Patent number: 5179040
    Abstract: A novel semiconductor laser device includes a P-type semiconductor substrate, an N-type InP current blocking layer on the substrate, a P-type InP buried layer of which has the same thickness as and is surrounded by the first current blocking layer, and a ridge, on the buried layer, having a double heterojunction structure therein and including a stack of a planar P-type first InP cladding layer, a planar InGaAsP active layer, and a planar N-type second InP cladding layer. The ridge has a width of the same order as that of the buried layer. A P-type InP current blocking layer is disposed on the N-type current blocking layer burying the ridge and an N-type contact layer is formed opposite and in contact with the P-type current blocking layer and the N-type cladding layer. The conductivity types of the layers can be reversed.
    Type: Grant
    Filed: September 23, 1991
    Date of Patent: January 12, 1993
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Ryo Hattori
  • Patent number: 5171707
    Abstract: A method of fabricating a semiconductor laser device includes disposing a lower cladding layer, a superlattice active layer, an upper cladding layer, and a contact layer in the named order on a substrate, forming resonator end surfaces, disposing, on the resonator end surfaces, films containing a material that disorders the semiconductor superlattice structure when diffused into the superlattice structure, and passing a current between the substrate and the contact layer to cause laser oscillations. The laser oscillations produce laser light that is absorbed at the resonator end surfaces. The resonator end surfaces are locally heated due to absorption of laser light whereby the disorder-causing material is diffused from the films into the resonator end surfaces and the semiconductor superlattice structure in the vicinity of the resonator end surfaces is thereby disordered to form window regions.
    Type: Grant
    Filed: August 13, 1991
    Date of Patent: December 15, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Kazuhisa Takahashi
  • Patent number: 5158908
    Abstract: Distributed Bragg Reflectors of high efficacy based on alternating layers of large difference in refractive index are fabricated by epitaxial growth followed by etchant removal and back-filling to produce a structure in which alternation is between layers of retained epitaxially grown material and layers of back-filled material. Such reflectors may serve simply as mirrors or may be incorporated in a variety of devices including lasers, LEDs, detectors, optical switches in which the DBRs serve e.g. for cavitation.
    Type: Grant
    Filed: September 28, 1990
    Date of Patent: October 27, 1992
    Assignee: AT&T Bell Laboratories
    Inventors: Greg E. Blonder, Edwin A. Chandross, Seng-Tiong Ho, Samuel L. McCall, Richart E. Slusher, Kenneth W. West
  • Patent number: 5153148
    Abstract: The invention is directed to a semiconductor laser wherein the first embodiment is characterized in that the first upper portion cladding layer is assumed to be a double layer construction, the upper layer portion is assumed to be higher in carrier concentration than the lower layer portion, the series resistance component is restrained, so that the sequential direction voltage V.sub.F may be lowered without damaging the other characteristics such as oscillation start current I th and so on.
    Type: Grant
    Filed: October 30, 1990
    Date of Patent: October 6, 1992
    Assignee: Rohm Co., Ltd.
    Inventors: Hajime Sakiyama, Haruo Tanaka, Masato Mushiage
  • Patent number: 5147825
    Abstract: An improved process for fabricating photonic circuits is disclosed. The inventive process starts with a growth of a base wafer comprising a stack of epitaxial layers of various materials. At least a portion of each of the material layers will ultimately be a functioning part of any of a number of devices which will form the PIC or will serve a role in at least one of the fabrication processing steps. Specific inventive processing steps are addressed to (1) interconnecting passive waveguides, active devices, and grating filtering regions without the substantial optical discontinuities which appear in the prior art, and (2) etching continuous waveguide mesas to different depths in different regions of the PIC so as to optimize the performance of each PIC device.
    Type: Grant
    Filed: August 26, 1988
    Date of Patent: September 15, 1992
    Assignee: Bell Telephone Laboratories, Inc.
    Inventors: Thomas L. Koch, Uziel Koren
  • Patent number: 5145807
    Abstract: Carrier injection layers are formed on an Al.sub.x Ga.sub.1-x As clad layer of high resistance by embedding and re-growth with the use of crystal growth processes such as MO-VPE or MO-MBE where material supply sources are all provided by gas sources, whereby it is not required to mesa-etch embedding regions to a depth reaching a substrate. The formation of any separate blocking layer is dispensed with, any possible influence of the substrate is elminated, and the time constant is decreased by decreasing the inter-electrode capacity.
    Type: Grant
    Filed: June 29, 1990
    Date of Patent: September 8, 1992
    Assignee: Mitsubishi Kasei Corporation
    Inventors: Kenji Shimoyama, Hideki Gotoh
  • Patent number: 5145792
    Abstract: A semiconductor optical device having a quantum well structure which can easily integrate plural optical devices of band gaps which are different from each other, and yet can achieve a high coupling coefficient by means of disordering the quantum well structure to form a waveguide region except for the portion which is used as an active region. Non-absorbing edges can be formed on the semiconductor laser on the optically integrated circuits by disordering the facets of the quantum well structure with ion implantation and thermal processing.
    Type: Grant
    Filed: November 27, 1991
    Date of Patent: September 8, 1992
    Assignee: Optical Measurement Technology Development Co., Ltd.
    Inventor: Takaaki Hirata
  • Patent number: 5143864
    Abstract: A semiconductor laser device having an active layer sandwiched by semiconductor layers having larger energy band gaps than that of the active layer, includes a semiconductor absorption layer having an energy band gap no larger than that of the active layer and having a thickness periodically changing in the cavity length direction of the resonator, close to the active layer so that light which is generated at the active layer reaches the absorption layer, and a semiconductor refractive index matching layer, having a larger energy band gap than that of the active layer and a higher refractive index than those of the semiconductor layers sandwiching the active layer, to make the equivalent refractive indices in layer thickness direction substantially equal along the resonator direction.
    Type: Grant
    Filed: July 29, 1991
    Date of Patent: September 1, 1992
    Assignee: Misubishi Denki Kabushiki Kaisha
    Inventors: Akira Takemoto, Hitoshi Watanabe, Masatoshi Fujiwara, Syoichi Kakimoto
  • Patent number: 5124279
    Abstract: A method of making an integrated semiconductor laser on a common substrate including at least two active regions, each active region oscillating at a respective, different wavelength, including producing a precursor laser structure by successively growing on a semiconductor substrate a first conductivity type semiconductor first cladding layer, an active layer including at least one compound semiconductor quantum well layer sandwiched between compound semiconductor quantum barrier layers, and a second conductivity type semiconductor second cladding layer, the quantum barrier layers having a larger energy band gap than and including at least one more element than the quantum well layer, annealing the precursor structure including controlling at first and second spaced apart regions the diffusion of the at least one more element from the quantum barrier layers into the quantum well layer to produce first and second spaced apart active regions in the active layer having different effective lasing energy band gap
    Type: Grant
    Filed: November 1, 1990
    Date of Patent: June 23, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Katsuhiko Goto
  • Patent number: 5116767
    Abstract: A method for imnproving the reliability of InGaAsP lasers in which the lasers are subjected to sulfide passivation so as to passivate defects on their facets. The lasers are then tested to determine whether any laser has an internal defect. For examples, all lasers can be tested at an electrostatic discharge (ESD) level which would cause any laser having an internal defect to fail. Failed lasers are discarded. The passivation greatly increases the ESD failure level for facet defects, and the ESD screening removes those lasers having internal defects. Thereby, those lasers remaining in the lot have greatly increased reliability to ESD.
    Type: Grant
    Filed: September 9, 1991
    Date of Patent: May 26, 1992
    Assignee: Bell Communications Research, Inc.
    Inventors: Louis F. DeChiaro, Claude J. Sandroff
  • Patent number: 5108948
    Abstract: A method of producing a semiconductor device such as a semiconductor laser having a controllably disordered superlattice. The superlattice is grown epitaxially and in the same epitaxial growth process a heavily selenium doped semiconductor layer is also grown in a known spatial relationship to the superlattice. The doped layer is patterned as by etching and then the device is annealed to diffuse selenium impurities from the doped layer. The time and temperature of annealing are controlled such that the impurities diffuse into and thereby disorder regions of the superlattice layer, leaving a non-disordered region which can serve as a resonator in a laser.
    Type: Grant
    Filed: November 17, 1988
    Date of Patent: April 28, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takashi Murakami, Kanamf Otaki, Hisao Kumabe
  • Patent number: 5104824
    Abstract: A method of etching and regrowing III-V compounds in a sharply defined vertical feature. Molecular beam epitaxy is used to grow a laterally undefined vertical-cavity, surface-emitting diode laser structure from semiconducting III-V materials. The structure includes interference mirrors defining the end of a Fabry-Perot cavity and a quantum-well layer in the middle of the cavity. A tungsten mask is then defined over the areas of the intended two-dimensional array of lasers. A chemically assisted ion beam etches through to the bottom of the laser structure to from an array of high aspect-ratio pillars. A thermal chlorine gas etch removes a portion of the sidewalls of the pillars without attacking the tungsten, thereby removing ion-beam damage at the sides of the vertical-cavities and creating a lip of the tungsten mask overhanging the pillar sidewall. Organo-metallic chemical vapor deposition is used to regrow III-V material around the pillars. This growth process can quickly planarize the pillars.
    Type: Grant
    Filed: November 6, 1990
    Date of Patent: April 14, 1992
    Assignee: Bell Communications Research, Inc.
    Inventors: Edward M. Clausen, Jr., Etienne G. Colas, Ann C. Von Lehmen
  • Patent number: 5102825
    Abstract: Planar-buried-heterostructure, graded-index, separate-confinement-heterostructure semiconductor diode laser 10 includes a single quantum well or multi-quantum well active stripe 12 disposed between a p-type compositionally graded Group III-V cladding lever 14 and an n-type compositionally graded Group III-V cladding layer 16. The laser 10 includes an iion implanted n-type region 28 within the p-type cladding layer 14 and further includes an ion implanted p-type region 26 within the n-type cladding layer 16. The ion implanted regions are disposed for defining a lateral extent of the active stripe.
    Type: Grant
    Filed: March 28, 1991
    Date of Patent: April 7, 1992
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Thomas M. Brennan, Burrell E. Hammons, David R. Myers, Gregory A. Vawter
  • Patent number: 5093278
    Abstract: According to this invention, a first cladding layer of a first conductivity type, an active layer, a second cladding layer of a second conductivity type, and a cap layer much more susceptible to side etching than the second cladding layer susceptible to side etching than the second cladding layer are sequentially grown on a (100) crystal plane of a semiconductor substrate of the first conductivity type, and a stripe-like mask extending in a <011> direction is formed on the grown substrate with respect to each layer of the stacked substrate. This etching is performed in a crystal orientation for forming a reverse triangular mesa. However, since the cap layer is made of a material susceptible to side etching, a rounded mesa is formed. Thereafter, when a burying layer is formed on the etched portion by a vapor phase epitaxy method, the burying layer can be made to have a flat surface depending on crystal orientations.
    Type: Grant
    Filed: September 21, 1990
    Date of Patent: March 3, 1992
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hidenori Kamei
  • Patent number: 5087587
    Abstract: A window semiconductor laser device comprising a stripe-channeled substrate, an active layer for laser oscillation and a cladding layer disposed under the active layer, wherein the surface of the active layer is flat and the thickness of the portion of the active layer corresponding to the striped channel of said substrate in each of the window regions in the vicinity of the facets is thinner than that of the portion of the active corresponding to the striped channel of said substrate in the stimulated region positioned between the window regions.
    Type: Grant
    Filed: February 9, 1987
    Date of Patent: February 11, 1992
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Taiji Morimoto, Shigeki Maei, Hiroshi Hayashi, Saburo Yamamoto
  • Patent number: 5077878
    Abstract: A method of passively aligning optical receiving elements such as fibers to the active elements of a light generating chip includes the steps of forming two front and one side pedestal structures on the surface of a substrate body, defining a vertical sidewall of the chip to form a mating channel having an edge at a predetermined distance from the first active element, mounting the chip epi-side down on the substrate surface, and positioning the fibers in fiber-receiving channels to that a center line of each fiber is aligned to a center line of a respective active element. When mounted, the front face of the chip is abutting the contact surfaces of the two front pedestals, and the defined sidewall of the mating channel is abutting the contact surface of the side pedestal. The passive alignment procedure is also effective in aligning a single fiber to a single active element.
    Type: Grant
    Filed: July 11, 1990
    Date of Patent: January 7, 1992
    Assignee: GTE Laboratories Incorporated
    Inventors: Craig A. Armiento, Chirravuri Jagannath, Marvin J. Tabasky, Thomas W. Fitzgerald, Harry F. Lockwood, Paul O. Haugsjaa, Mark A. Rothman, Vincent J. Barry, Margaret B. Stern
  • Patent number: 5079185
    Abstract: A semiconductor laser includes a groove in a GaAs first current blocking layer, which extends to an Al.sub.x Ga.sub.(1-x) As second clad layer beneath the first blocking layer. The width of the groove periodically changes along the length of the resonator. Over the regions of the first current blocking layer where the groove has a smaller width, a Al.sub.z Ga.sub.(1-z) As second current blocking grating layer is formed. An Al.sub.x Ga.sub.(1-x) As third current blocking layer is disposed on the second current blocking layer and the portions of the first current blocking layer not covered by the second current blocking layer. The variation of the width of the groove is achieved by selective etching in gaseous hydrogen chloride by irradiation with an arsenic molecular beam, or by placing a liquid-phase solvent.
    Type: Grant
    Filed: October 10, 1990
    Date of Patent: January 7, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hitoshi Kagawa, Tetsuya Yagi
  • Patent number: 5063173
    Abstract: A method for passivating mirrors in the process of fabricating semiconductor laser diodes is disclosed. Key steps of the method are: (1) providing a contamination-free mirror facet, followed by (2) an in-situ application of a continuous, insulating (or low conductive) passivation layer. This layer is formed with material that acts as a diffusion barrier for impurities capable of reacting with the semiconductor but which does not itself react with the mirror surface.The contamination-free mirror surface is obtained by cleaving in a contamination-free environment, or by cleaving in air, followed by mirror etching, and subsequent mirror surface cleaning. The passivation layer consists of Si, Ge or Sb.
    Type: Grant
    Filed: June 15, 1990
    Date of Patent: November 5, 1991
    Assignee: International Business Machines Corporation
    Inventors: Marcel Gasser, Ernst E. Latta
  • Patent number: 5057442
    Abstract: A light-emitting diode prepared by a new process is disclosed. The light-emitting diode has compound semiconductor epitaxial layers composed of GaAs.sub.1-x P.sub.x (0.ltoreq.x.ltoreq.1) on a compound semiconductor GaP single-crystal substrate, and has a light-emitting layer provided with a p-n junction formed in the surface layer region of the epitaxial layers. The diode is characterized in that it has a total maximum thickness of the epitaxial layers 20 to 40 .mu.m.The process for preparing the diode is characterized in that the process can determine a required maximum thickness of the compound semiconductor epitaxial layers by presuming light output power from the thickness of the epitaxial layers based on the following equation:L=exp(Ax.sub.0 +B)+Cwhere A, B and C are definite values obtained from experiments conducted, L is light output power and x.sub.0 is the total thickness of the epitaxial layers.
    Type: Grant
    Filed: May 30, 1990
    Date of Patent: October 15, 1991
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventor: Hitoshi Habuka
  • Patent number: 5055422
    Abstract: The present invention relates to processes for the construction of semiconductor lasers.The process according to the invention is essentially characterized in that it consists in forming a layer 1 of a laser semiconductor active medium, in forming an optical cavity 2 associated with this layer, in disposing, on at least a part of the surface of the layer, first 6 and second 7 layers of materials of impurities of opposite polarities, in causing diffusion into the active medium of at least a part of the two materials of impurities to form, in the first layer, a cylinder 8 axis substantially parallel to the axis of the optical cavity and formed of two semi-cylindrical half-shells 9, 10 of diffused impurities of opposite polarities, and in connecting two conductors 12 of the electrical energy respectively to the two half-shells.Application to the construction of a plurality of laser diodes on one and the same support substrate, to create a homogeneous and dense single laser beam.
    Type: Grant
    Filed: July 24, 1990
    Date of Patent: October 8, 1991
    Assignee: Thomson-CSF
    Inventors: Claude Weisbuch, Baudouin De Cremoux, Jean P. Pocholle
  • Patent number: 5053356
    Abstract: A semiconductor laser particularly adapted for operation in the self-pulsation mode and method for production thereof. A central mesa is formed in the upper cladding layer and normally requires relatively thick sections at either side of the mesa in order to form a wageguide of sufficient thickness to cause self-pulsation operation. In order to control the thickness of the upper cladding layer bounding the mesa, the mesa is first formed by etching the regions bounding the mesa to relatively thin sections capable of ready gauging by optical interferometry. A composite upper clading layer is then formed by utilizing MOCVD crystal growth techniques to form a buffer layer on the upper cladding layer bounding the mesa, the buffer layer having an aluminum content about the same as the aluminum content of the AlGaAs upper cladding layer.
    Type: Grant
    Filed: September 25, 1990
    Date of Patent: October 1, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigeru Mitsui, Ryo Hattori
  • Patent number: 5047364
    Abstract: A multi-point light emission type semiconductor laser device including a plurality of light emission points which are produced on a p type or n type semiconductor layer monolithically and are capable of being driven independently includes electrically insulating or semi-insulating semiconductor regions provided at intermediate portions of light emission points in the p type or n type semiconductor layer. A separation groove is further produced up to reaching the insulating or semi-insulating regions from the side opposite to the semiconductor layer. Thus, respective light emission points are perfectly electrically separated each other by this separation groove and the region.
    Type: Grant
    Filed: March 8, 1990
    Date of Patent: September 10, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Ryo Hattori
  • Patent number: 5045499
    Abstract: Disclosed are a distributed Bragg reflector type semiconductor laser and a method of manufacturing such a laser a high yields, in which the upper surface of an active waveguide is covered by an external waveguide, the external waveguide at side portions thereof, the external waveguide is coupled with the edge surfaces of the active waveguide without any gap remaining, and the coupling ratio of the active waveguide and external waveguide is high.
    Type: Grant
    Filed: September 26, 1989
    Date of Patent: September 3, 1991
    Assignees: Research Development Corporation of Japan, Sumitomo Electric Industries, Ltd., Tokyo Institute of Technology
    Inventors: Hideaki Nishizawa, Mitsuo Takahashi, Yasuharu Suematsu
  • Patent number: 5045498
    Abstract: A semiconductor laser diode includes a first buffer layer, a second buffer layer and an active layer sandwiched between the two buffer layers. The active layer contains dopant ions where the dopant ions are such that energy transfer between the unimplanted material in the active layer and the dopant ions implanted causes lasing action substantially at a single frequency characteristic of the dopant ions. The two buffer layers confine light emitted by the active layer. The second buffer layer is grown epitaxially on the active layer. In the preferred embodiment, the structure is made by first growing a thin second buffer layer epitaxially on the active layer. The dopant ions are then implanted into the active layer through the thin second buffer layer. The structure is heated to a high temperature to anneal the structure and to activate the dopants. The second buffer layer is then further grown to make it thicker so as to be more effective in confining the light emission in the active layer.
    Type: Grant
    Filed: August 10, 1990
    Date of Patent: September 3, 1991
    Assignee: Hewlett-Packard Company
    Inventors: Shih-Yuan Wang, Michael R. T. Tan
  • Patent number: 5045500
    Abstract: A semiconductor laser includes a first cladding layer having a forward mesa with at least one end at least partially spaced from the adjacent facet of the laser. A current blocking layer buries the mesa at its sides and at least partially at the ends of the mesa so that the ends are at least partially spaced from the facets. The current blocking layer reduces current injection and surface recombination at the facets at least partially spaced from the mesa ends, thereby increasing the catastrophic optical damage level of the laser. The mesa is formed without etching or exposing the active layer so that formation of interfaces that refract light or shorten laser lifetime are avoided. An increase in COD level of about 20 percent is achieved in the invention.
    Type: Grant
    Filed: July 25, 1990
    Date of Patent: September 3, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigeru Mitsui, Ryo Hattori, Tetsuya Yagi
  • Patent number: 5037776
    Abstract: A method, and devices produced therewith, for the epitaxial growth of sub-micron semiconductor structures with at least one crystal plane-dependently grown, buried active layer (24) consisting of a III-V compound. The active layer (24) and adjacent embedding layers (23, 25) form a heterostructure produced in a one-step growth process not requiring removal of the sample from the growth chamber in between layer depositions. The layers of the structure are grown on a semiconductor substrate (21) having a structured surface exposing regions of different crystal orientation providing growth and no-growth-planes for the selective growth process. The method allows the production of multiple, closely spaced active layers and of layers consisting of adjoining sections having different physical properties.
    Type: Grant
    Filed: September 14, 1989
    Date of Patent: August 6, 1991
    Assignee: International Business Machines Corporation
    Inventors: Yvan Galeuchet, Volker Graf, Wilhelm Heuberger, Peter Roentgen
  • Patent number: 5034334
    Abstract: An advantageous method of fabricating lasers adapted for use in a multichannel analog optical fiber communication system, e.g., a CATV system, is disclosed. A laser generally can be used in such a communication system only if it meets, inter alia, very stringent intermodulation specifications. To identify such lasers typically requires extensive testing. It has now been discovered that certain readily determinable parameters can be used to predict the intermodulation behavior of a given device. This discovery makes possible a simpler, and therefore less costly, process of identifying suitable lasers, resulting in a more economical method of making lasers for the stated application. The method comprises measuring the light versus current (L versus I) characteristic of a given laser, determining therefrom the first, second, and possibly higher, order derivatives of L with respect to I, and determining thereform a parameter that is a predictor of the distortion behavior of the laser.
    Type: Grant
    Filed: October 13, 1989
    Date of Patent: July 23, 1991
    Assignee: AT&T Bell Laboratories
    Inventors: Edward J. Flynn, Carl J. McGrath, Paul M. Nitzsche, Charles B. Roxlo
  • Patent number: 5028562
    Abstract: A semiconductor laser includes, serially disposed, a semiconductor substrate of a first conductivity type, a semiconductor current blocking layer of a second conductivity type opposite the first conductivity tyupe, a first semiconductor cladding layer of the first conductivity type, an active semiconductor layer, a second semiconductor cladding layer of the second conductivity type, and a semiconductor contacting layer of the second conductivity type, and a structure for laterally confining the transverse flow of electrical current through the layers, the structure including a portion of the first cladding layer being disposed in a longitudinal groove extending through the current blocking layer into the substrate and high resistance longitudinal stripes disposed adjacent the groove between the second cladding layer and the current blocking layer, the high resistance stripes forming discontinuities in the active semiconductor layer.
    Type: Grant
    Filed: June 14, 1990
    Date of Patent: July 2, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Akihiro Shima
  • Patent number: 5028563
    Abstract: A PbTe/PbEuSeTe buried heterostructure tunable diode laser and array and the method for making the same. The active region layer is buried between two lead salt semiconductor layers containing europium and selenium that are mutually of opposite conductivity type and have substantially the same lattice constant as the active region layer. In addition, the europium and selenium containing lead chalcogenide layers have an energy band gap greater than the active buried layer and an index of refraction less than the active layer. The buried structure enhances electrical and optical confinement, reduces threshold currents, and provides a stable single mode laser. Strontium, calcium or tin may be used in place of the europium. The buried laser and array are produced using a two-step molecular beam epitaxy method.
    Type: Grant
    Filed: January 23, 1990
    Date of Patent: July 2, 1991
    Assignee: Laser Photonics, Inc.
    Inventors: Zeev Feit, Douglas Kostyk, Robert J. Woods
  • Patent number: 5026662
    Abstract: A method of undercutting mesa structures in which the lateral extent of the undercut is determined by a prior fabrication stage in which channels (5, 6) are etched and then infilled with a different material. The mesa is formed over the channels (5,6) and a selective etch is used to undercut the mesa, the extent of the undercut (11) being limited by the location of the infilled channels (5, 6). For mechanical stability and insulation the undercuts (11) are filled or partly filled with dielectric (10).
    Type: Grant
    Filed: May 24, 1990
    Date of Patent: June 25, 1991
    Assignee: British Telecommunications public limited company
    Inventor: Leslie D. Westbrook
  • Patent number: 5023198
    Abstract: A quaternary semiconductor diffraction grating, such as an InGaAsP grating suitable for a DFB laser, is embedded in a semiconductor substrate, such as InP. In one embodiment, the grating is fabricated by(1) forming on the top surface of an InP substrate body an epitaxial layer of InGaAsP coated with an epitaxial layer of InP;(2) forming a pattern of apertures penetrating through the layers of InP and InGaAsP; and(3) heating the body to a temperature sufficient to cause a mass transport of InP from the InP epitaxial layer, the thickness of the InP layer being sufficient to bury the entire surface of the InGaAsP layer with InP.
    Type: Grant
    Filed: February 28, 1990
    Date of Patent: June 11, 1991
    Assignee: AT&T Bell Laboratories
    Inventor: Keith E. Strege
  • Patent number: 5023199
    Abstract: A method of diffusing Zn into AlGaInP using Al.sub.x G.sub.1-x As (0.ltoreq.x.ltoreq.1) as a diffusion stopping at a position of predetermined depth from the surface of the AlGaInP, or using Al.sub.x Ga.sub.1-x As (0.ltoreq.x.ltoreq.1) as a diffusion mask which is disposed on the surface of the AlGaInP.
    Type: Grant
    Filed: January 4, 1990
    Date of Patent: June 11, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takashi Murakami, Takashi Motoda
  • Patent number: 5021361
    Abstract: In a monolithic OEIC in which an FET and a light-emitting device are integrated, the light-emitting device has a first clad layer, an active layer, and a second clad layer stacked on a substrate, the FET has a channel layer and source and drain layers with a high impurity concentration stacked on the substrate, etching mask layers on the source and drain layers, and a gate electrode formed on a channel layer between source and drain electrodes and the source and drain layers, the first clad layer of the light-emitting diode and the source and drain layers with a high impurity concentration of the FET are formed of the same semiconductor layer, and an active layer of the light-emitting device and the etching mask layers of the FET are formed of the same semiconductor layer.
    Type: Grant
    Filed: December 11, 1989
    Date of Patent: June 4, 1991
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Jun'ichi Kinoshita, Nobuo Suzuki, Motoyasu Morinaga, Yuzo Hirayama, Masaru Nakamura
  • Patent number: 5013682
    Abstract: Selective growth of GaAs and related semiconductors (34) by use of tungsten silicide and related materials for growth masks (36) plus devices incorporating the selective growth plus use of the growth masks as electrical contacts are disclosed. The deposition of semiconductor (38) on such masks (36) is inhibited and single crystal vertical structures (34) grow on unmasked regions of the lattice-matched substrate (32). Variation of the mask (36) composition can vary the inhibited deposition on the mask (36) from small isolated islands of polycrystalline semiconductor (38) to a uniform layer of polycrystalline semiconductor abutting the single crystal structures. Preferred embodiments include bipolar transistors with the selectivity grown structure forming the base and emitter or collector and the mask being the base contact and also include lasers with the vertical structures including the resonant cavities with the mirros being the sidewalls of the vertical structures.
    Type: Grant
    Filed: June 30, 1989
    Date of Patent: May 7, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: Donald L. Plumton, Liem T. Tran, Hung-Dah Shih
  • Patent number: 5013684
    Abstract: In situ removal of selected or patterned portions of semiconductor layers is accomplished by induced evaporation enhancement to form patterned buried impurity layers in semiconductor devices, such as heterostructure lasers and array lasers, which function as buried impurity induced layer disordering (BIILD) sources upon subsequent annealing. These layers may be formed to either function as buried impurity induced layer disordering (BIILD) sources or function as a reverse bias junction configuration of confining current to the active region of a laser structure. Their discussion here is limited to the first mentioned function.
    Type: Grant
    Filed: March 24, 1989
    Date of Patent: May 7, 1991
    Assignee: Xerox Corporation
    Inventors: John E. Epler, Thomas L. Paoli
  • Patent number: 4990465
    Abstract: A method and apparatus for forming a monolithic surface emitting laser diode array by providing vertical partly light transmissive mirror surfaces opposite parabolic light reflective mirror surfaces formed adjacent the active buried layer of a heterostructure diode laser. The mirror surfaces are preferably formed using a mass-transport heating process. Other mirror shapes may be formed in accordance with the invention.
    Type: Grant
    Filed: November 1, 1989
    Date of Patent: February 5, 1991
    Assignee: Massachusetts Institute of Technology
    Inventors: Zong-Long Liau, James N. Walpole