Patents by Inventor Iain D. Calder

Iain D. Calder 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).

  • Patent number: 5452178
    Abstract: A capacitor structure for a memory element of an integrated circuit is provided. The capacitor is formed within a via hole defined through a first dielectric layer, and comprises a bottom electrode defined by an underlying conductive layer, and a capacitor dielectric filling the via with a dielectric barrier layer lining the via and separating the capacitor dielectric from the first dielectric layer. The capacitor dielectric is characterized by a material with high dielectric strength, preferably a ferroelectric material. An overlying conductive layer defines a top electrode contacting the capacitor dielectric. The barrier layer may comprise dielectric sidewall spacer formed within the via, or alternatively may comprise a region of mixed composition formed by interdiffusion of the first dielectric layer and the capacitor dielectric. The resulting capacitor structure is simple and compact, and may be fabricated with known CMOS, Bipolar or Bipolar-CMOS processes for submicron VLSI and ULSI integrated circuit.
    Type: Grant
    Filed: April 7, 1994
    Date of Patent: September 19, 1995
    Assignees: Northern Telecom Limited, McMaster University
    Inventors: Ismail T. Emesh, Iain D. Calder, Vu Q. Ho, Gurvinder Jolly, Lynnette D. Madsen
  • Patent number: 5330931
    Abstract: A method is provided for forming a capacitor structure for a memory element of an integrated circuit. The method comprises providing a first conductive electrode, forming a layer of a first dielectric material thereon, opening a via hole through the dielectric layer, providing within the via opening a capacitor dielectric having a higher dielectric strength than the first dielectric, the capacitor dielectric contacting the first electrode, planarizing the resulting structure and then forming a second conductive electrode thereon. Preferably, when the second dielectric comprises a ferroelectric dielectric material, sidewalls of the via opening are lined with a dielectric barrier layer to provide diffusion barrier between the ferroelectric and first dielectric layer. Advantageously, planarization is accomplished by chemical mechanical polishing to provide fully planar topography.
    Type: Grant
    Filed: September 23, 1993
    Date of Patent: July 19, 1994
    Assignees: Northern Telecom Limited, McMaster University
    Inventors: Ismail T. Emesh, Iain D. Calder, Vu Q. Ho, Gurvinder Jolly, Lynnette D. Madsen
  • Patent number: 4804633
    Abstract: A silicon-on-insulator substrate having a very low threading dislocation density is made by implanting oxygen ions into a silicon substrate while heating the substrate to form a layer of silicon dioxide buried in the silicon substrate and annealing the implanted substrate at high temperature in a novel furnace incorporating a polysilicon tube to constrain the annealing temperature to be uniform over the entire substrate. The silicon-on-insulator substrate is particularly useful for the manufacture of semiconductor devices formed in thin silicon films.
    Type: Grant
    Filed: February 18, 1988
    Date of Patent: February 14, 1989
    Assignee: Northern Telecom Limited
    Inventors: Thomas W. Macelwee, Iain D. Calder
  • Patent number: 4683645
    Abstract: In a metal oxide semiconductor field effect transistor fabrication process, refractory metal is deposited over designated source and drain areas within a silicon substrate. Refractory metal and silicon at the interface is then mixed by ion implantation of a heavy neutral ion species such as germanium. To minimize source/drain junction depth, the source and drain locations can be subjected to bombardment by a lighter ion such as silicon which amorphizes silicon to a predetermined depth under the designated source and drain regions and so substantially confines dopant diffusion to the silicon amorphized region. To render the source and drain of desired conductivity type, an ion implantation of a non-neutral ion is then performed.
    Type: Grant
    Filed: December 24, 1985
    Date of Patent: August 4, 1987
    Assignee: Northern Telecom Limited
    Inventors: Hussein M. Naguib, Iain D. Calder, Vu Q. Ho, Abdalla A. Naem
  • Patent number: 4680609
    Abstract: A vertically integrated CMOS logic gate has spaced semiconductor layers with control gates located between the layers and insulated from them by gate oxide. Transistors formed in one semiconductor layer are vertically aligned with transistors formed in the other semiconductor layer. Pairs of vertically coincident transistors have common control gates and certain of the pairs have integral drain regions. Transistors in one layer are series connected in an open loop configuration and transistors in the other layer are parallel connected in a closed loop configuration. The logic gate function depends on voltages applied to the common control gates and to the open and closed loops. By the vertical integration, a two-input NAND or NOR gate can be made using less area than that required for two simple MOS transistors.
    Type: Grant
    Filed: September 24, 1984
    Date of Patent: July 14, 1987
    Assignee: Northern Telecom Limited
    Inventors: Iain D. Calder, Thomas W. Macelwee, Abdalla A. Naem
  • Patent number: 4651408
    Abstract: In a process for manufacturing vertically integrated MOS devices and circuits, gate oxide and a gate are formed on a semiconductor substrate such as a silicon substrate. A layer of polysilicon is then deposited over the wafer, the polysilicon contacting the substrate silicon through a window in the gate oxide. The substrate silicon and the polysilicon are then laser melted and cooled under conditions that encourage crystal seeding from the substrate into the polysilicon over the gate. Subsequently, ions are implanted into the silicon substrate and the polysilicon to form source and drain regions. By introducing the source and drain dopants after melt associated seeding of the polysilicon, the risk of dopant diffusion into the device channel regions is avoided.
    Type: Grant
    Filed: May 17, 1984
    Date of Patent: March 24, 1987
    Assignee: Northern Telecom Limited
    Inventors: Thomas W. MacElwee, Iain D. Calder, James J. White
  • Patent number: 4561906
    Abstract: An integrated circuit is fabricated with some redundant capacity by forming potential electrically conducting links which can subsequently be made electrically when extra circuit capacity is required. Field oxide is grown on a silicon substrate and then a layer of polysilicon deposited over the oxide. At the redundancy sites where electrical connections may subsequently be made, an anti-reflective silicon nitride coating is deposited and photodefined. The areas of this coating are used as masks in order to diffuse dopant into the polysilicon at parts of the polysilicon laterally adjacent the redundancy sites. When later it is necessary to bring spare capacity into the circuit the complete circuit is scanned with a continuous wave laser. The laser melts the polysilicon under the nitride mask permitting the dopant to diffuse from the adjacent parts of the polysilicon and so form a conducting link.
    Type: Grant
    Filed: October 24, 1983
    Date of Patent: December 31, 1985
    Assignee: Northern Telecom Limited
    Inventors: Iain D. Calder, Hussein M. Naguib
  • Patent number: 4503468
    Abstract: At each of a pair of linked terminals, an image is generated at local and remote input devices. The generated image is projected onto a viewing screen and, while exhibited, further locally or remotely generated data is used to alter the generated image and, consequently, to alter the projected image. Data can, for example, be generated by means of a document scanner and a manually operated X-Y pen digitizer.
    Type: Grant
    Filed: October 9, 1981
    Date of Patent: March 5, 1985
    Assignee: Northern Telecom Limited
    Inventors: Nur M. Serinken, Iain D. Calder, James Gale, Norman C. Fletcher
  • Patent number: 4476475
    Abstract: In a stacked metal-oxide-semiconductor (SMOS) transistor, the transistor source, drain and channel each have a lower part formed in a silicon substrate and an upper part composed of recrystallized polysilicon. The device gate is located between the upper and lower channel parts. By vertically integrating a MOS transistor, performance limitations imposed by the direct scaling approach to device miniaturization are avoided.
    Type: Grant
    Filed: November 19, 1982
    Date of Patent: October 9, 1984
    Assignee: Northern Telecom Limited
    Inventors: Abdalla A. Naem, Hussein M. Naguib, Iain D. Calder, Albert R. Boothroyd
  • Patent number: 4415383
    Abstract: In the manufacture of VLSI (very large scale integrated) MOS (metal-oxide-semiconductor) circuits, a polysilicon gate is deposited on an oxide layer overlaying a silicon substrate. Ideally, the polysilicon gate is made extremely small and with sharply defined vertical boundaries. The invention proposes depositing a polysilicon layer, covering a region of the layer with an antireflective coating, and laser annealing the layer. Laser radiation is absorbed to a higher level by the coated region than elsewhere and consequently the polysilicon layer in this region melts and recrystallizes into large grains. The polysilicon layer is then etched using etch conditions ensuring preferential etching of unrecrystallized polysilicon in comparison with recrystallized polysilicon. Consequently, except at the coated region, the polysilicon is etched quickly and there is very little undercutting of the gate region.
    Type: Grant
    Filed: May 10, 1982
    Date of Patent: November 15, 1983
    Assignee: Northern Telecom Limited
    Inventors: Abdalla A. H. Naem, Iain D. Calder, Hussein M. Naguib