Patents by Inventor Bertram Schwartz
Bertram Schwartz has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 4738934Abstract: Epitaxial layers of semi-insulating InP grown by MOCVD on conducting InP wafers make excellent substrates for III-V semiconductor devices. Particularly appealing is the low defect density obtained because of the conducting InP wafers and excellent insulating characteristics of the semi-insulating InP layer. The invention is a procedure for doping the insulating layer by ion implantation. Such a procedure is unusually advantageous for fabricating a variety of devices including MISFETs, MESFETs and JFETs.Type: GrantFiled: May 16, 1986Date of Patent: April 19, 1988Assignee: American Telephone and Telegraph Company, AT&T Bell LaboratoriesInventors: Wilbur D. Johnston, Jr., Judith A. Long, Albert T. Macrander, Bertram Schwartz, Shobha Singh
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Patent number: 4731293Abstract: A fabrication technique is described for making various devices in which a type of glass is used as a surface protection layer. The glass layers are put down by particle bombardment (generally sputtering or e-beam bombardment) of a phosphorus-containing silicate glass target. Devices with such layers are also described. Such glass layers are highly advantageous as encapsulating material, diffusion barrier layers, etc., particularly for optical type devices and certain semiconductor devices. Particularly important is the preparation procedure for the glass target used in the bombardment process. The glass layers are moisture stable, act as excellent barriers against diffusion, and are usable up to quite high temperatures without cracking or peeling. The glass layers also provide long-term protection against atmosphere components including water vapor, oxygen, atmosphere pollution contaminants, etc.Type: GrantFiled: June 20, 1986Date of Patent: March 15, 1988Assignee: American Telephone and Telegraph Company, AT&T Bell LaboratoriesInventors: David T. Ekholm, William H. Grodkiewicz, Bertram Schwartz, Shobha Singh, LeGrand G. Van Uitert, George J. Zydzik
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Patent number: 4645116Abstract: Indium is used to bond semiconductor lasers to their heat-sinks without the presence of a corrosive liquid flux. Fluxless bonding is achieved in a vacuum chamber in reducing ambients of CO or H.sub.2. Low strain bonds are achieved at bonding temperatures of approximately 180.degree.-240.degree. C. in CO and 220.degree.-230.degree. C. in H.sub.2. Void-free bonds are achieved in CO at temperatures as low as about 205.degree. C. The technique is applicable to other microelectronic chips such as LEDs, for example.Type: GrantFiled: September 5, 1984Date of Patent: February 24, 1987Assignee: AT&T Bell LaboratoriesInventors: Gerard E. Henein, Ralph T. Hepplewhite, Bertram Schwartz
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Patent number: 4599791Abstract: The property of materials in the GaAs/AlGaAs system, whereby at certain doses proton bombarded n-type material becomes highly resistive but p-type material remains highly conductive, is utilized to fabrication of integrated circuits which include buried semiconductor interconnections or bus bars between devices.Type: GrantFiled: November 28, 1983Date of Patent: July 15, 1986Assignee: AT&T Bell LaboratoriesInventors: Marlin W. Focht, Louis A. Koszi, Bertram Schwartz
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Patent number: 4597165Abstract: The property of materials in the InP system, whereby helium ion or deuteron bombarded p-type material becomes highly resistive but n-type material remains relatively conductive, is utilized to fabricate integrated circuits which include buried semiconductor interconnections or bus bars between devices.Type: GrantFiled: November 28, 1983Date of Patent: July 1, 1986Assignee: AT&T Bell LaboratoriesInventors: Federico Capasso, Marlin W. Focht, Albert T. Macrander, Bertram Schwartz
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Patent number: 4539743Abstract: The property of Group III-V compound materials, whereby ion bombarded material becomes highly resistive but recovers its original low resistivity by annealing at a temperature which is dopant and material dependant, is utilized to fabricate integrated circuits which include buried semiconductor interconnections or bus bars between devices.Type: GrantFiled: November 28, 1983Date of Patent: September 10, 1985Assignee: AT&T Bell LaboratoriesInventors: Philip J. Anthony, Robert L. Hartman, Louis A. Koszi, Bertram Schwartz
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Patent number: 4514896Abstract: Semiconductor light emitting devices, lasers and LEDs, are described in which the current flow channel is narrower near the top surface of the device and wider at its bottom near the active region. Also, described are several attenuation masks for fabricating the channels of these devices by particle bombardment.Type: GrantFiled: January 17, 1984Date of Patent: May 7, 1985Assignee: AT&T Bell LaboratoriesInventors: Richard W. Dixon, William B. Joyce, Louis A. Koszi, Richard C. Miller, Bertram Schwartz
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Patent number: 4504952Abstract: A TJS light emitting diode (laser or LED) comprises an isotype double heterostructure (DH) and a V-groove which penetrates the intermediate layer of the DH. The groove is filled with a region of semiconductor material which enables carrier injection to occur from the region into the intermediate layer, or conversely, depending on the relative bandgaps of the layer and region. Real-refractive index guiding by the groove is described.Type: GrantFiled: June 1, 1982Date of Patent: March 12, 1985Assignee: AT&T Bell LaboratoriesInventors: Robert L. Hartman, Louis A. Koszi, Bertram Schwartz
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Patent number: 4447905Abstract: Semiconductor light emitting devices, lasers and LEDs, are described in which the current flow channel is narrower near the top surface of the device and wider at its bottom near the active region. Also, described are several attenuation masks for fabricating the channels of these devices by particle bombardment.Type: GrantFiled: March 25, 1981Date of Patent: May 8, 1984Assignee: Bell Telephone Laboratories, IncorporatedInventors: Richard W. Dixon, Louis A. Koszi, Richard C. Miller, Bertram Schwartz
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Patent number: 4429231Abstract: A system (FIG. 1) for interrogating the ON-OFF status of an electrical switch (31) comprises a semiconductor body (4) containing a PN junction and means (5) for electrically connecting an auxiliary switch (32) coupled to the interrogated switch, or alternately (FIG. 2) the interrogated switch (32), across the PN junction. Light (7) of a first wavelength incident on the semiconductor body causes light of a second wavelength (11) to be emitted from the body when the switch is open (OFF), whereas no light is emitted from the body when the switch is closed (ON). Therefore, photoelectric detection of the emission vs. non-emission of light of the second wavelength from the semiconductor body indicates the OFF vs. ON status of the switch.Type: GrantFiled: November 25, 1981Date of Patent: January 31, 1984Assignee: Bell Telephone Laboratories, IncorporatedInventors: Bernard C. De Loach, Jr., Richard C. Miller, Bertram Schwartz
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Patent number: 4408331Abstract: Semiconductor lasers and LEDs are described in which the pumping current is constrained to flow from a relatively narrow upper channel formed by a V-groove, which extends to a depth short of the active region, through a relatively wider lower channel bounded by high resistivity regions, which extend from at least that depth into or through the active region. Also described are devices in which the V-groove is refilled with semiconductor material.Type: GrantFiled: March 25, 1981Date of Patent: October 4, 1983Assignee: Bell Telephone Laboratories, IncorporatedInventors: Robert L. Hartman, Louis A. Koszi, Bertram Schwartz
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Patent number: 4340967Abstract: This invention is a semiconductor junction laser which operates in a transverse mode, other than the fundamental mode, parallel to the p-n junction. An undesired transverse mode parallel to the p-n junction may be suppressed by introducing a lossy region within the laser where this mode has at least one of its maxima. The zero order transverse mode parallel to the p-n junction may be suppressed in a double heterostructure stripe geometry laser by introducing an optically or electrically lossy region in the current flow path of the laser where the zero order mode has its maximum. This double heterostructure stripe geometry laser operates linearly with respect to current in the first order transverse mode parallel to the p-n junction.Type: GrantFiled: June 2, 1980Date of Patent: July 20, 1982Assignee: Bell Telephone Laboratories, IncorporatedInventors: Richard W. Dixon, Bertram Schwartz
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Patent number: 4292512Abstract: The tracking problems of prior art optical monitoring (e.g., feedback stabilization) schemes are substantially alleviated by positioning a photodiode (PD 130) directly in the light path of the optical source (100) to be stabilized. The active (light-absorbing) layer (104) of the PD samples (absorbs) only a small portion of the light beam (140) emanating from the source and converts that portion to a photocurrent used in a feedback loop (120, 101) to control the excitation supplied to the source. The remaining, major portion (140') of the beam is transmitted unabsorbed through the PD active layer to utilization means (e.g., through an optical fiber 108 to a remote receiver). Advantageously, in one embodiment the PD is a double heterostructure (DH) in which the photocurrent is linearly related to the beam intensity. The use of discrete or integrated lens means (110, 110', 164, 166) to enhance coupling from the source to PD is described.Type: GrantFiled: June 19, 1978Date of Patent: September 29, 1981Assignee: Bell Telephone Laboratories, IncorporatedInventors: Richard C. Miller, Bertram Schwartz
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Patent number: 4227975Abstract: Plasma etching is described as a selective etch for dielectric masks such as SiO.sub.2, Si.sub.3 N.sub.4 and certain photoresists in the presence of native oxides of Group III-V compound semiconductors. This process can be used in the fabrication of mesa junction lasers and Burrus light emitting diodes.Type: GrantFiled: January 29, 1979Date of Patent: October 14, 1980Assignee: Bell Telephone Laboratories, IncorporatedInventors: Robert L. Hartman, Louis A. Koszi, Cyril J. Mogab, Bertram Schwartz
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Patent number: 4127862Abstract: A plurality n of double heterostructure photodiodes are coupled together by (n-1) interleaved n.sup.+ -p.sup.+ tunnel junctions to form a multi-layered integrated structure which has an open circuit photovoltage approaching the sum of the open circuit photovoltages of the individual photodiodes. In one embodiment, in which radiation to be detected is made incident normal to the layers, the absorbing layers of the photodiodes get progressively thicker away from the substrate. In a second embodiment, in which the radiation is made incident parallel to the layers, all of the absorbing layers have essentially the same thickness. In a third embodiment, in which radiation is made incident normal to the layers, the structure has a stepped configuration and all of the absorbing layers have essentially the same thickness.Type: GrantFiled: September 6, 1977Date of Patent: November 28, 1978Assignee: Bell Telephone Laboratories, IncorporatedInventors: Marc Ilegems, Louis A. Koszi, Bertram Schwartz
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Patent number: 4026741Abstract: A technique for preparing stoichiometric group III-V compound semiconductor surfaces involves a repetitive anodizing and etching sequence in an aqueous solution of appropriate pH and a basic solution, respectively. Surfaces treated in the described manner evidence a correct surface stoichiometry and minimum carbon contamination.Type: GrantFiled: June 16, 1976Date of Patent: May 31, 1977Assignee: Bell Telephone Laboratories, IncorporatedInventors: Chuan Chung Chang, Paul H. Citrin, Bertram Schwartz
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Patent number: 3959098Abstract: An electrolytic process for etching Group III - Group V semiconductive compounds, especially gallium-containing compound semiconductors. The sample to be etched is made the anode in an electrolytic cell wherein the electrolyte includes nitrate or chloride ions. Etching rates may be easily controlled according to the current supplied to the system.Type: GrantFiled: March 12, 1973Date of Patent: May 25, 1976Assignee: Bell Telephone Laboratories, IncorporatedInventor: Bertram Schwartz
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Patent number: H147Abstract: Helium-3 and helium-4 bombardment of InP over a fluence range of 10.sup.11 to 10.sup.16 ions/cm.sup.2 reproducibly forms highly resistive regions in both p-type and n-type single crystal material. Average peak resistivities are about 10.sup.9 ohm-cm for p-type InP and are about 10.sup.3 ohm-cm for n-type InP. High resistivity has also been produced in GaP, GaSb, GaAs, and InGaAs by helium bombardment. Stripe geometry lasers and planar photodiodes which incorporate helium-bombarded zones are described.Type: GrantFiled: May 31, 1983Date of Patent: November 4, 1986Assignee: AT&T Bell LaboratoriesInventors: Leonard C. Feldman, Marlin W. Focht, Albert T. Macrander, Bertram Schwartz