Patents by Inventor Sheldon Aronowitz

Sheldon Aronowitz 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: 5723896
    Abstract: An integrated circuit structure vertically isolated electrically from the underlying substrate is formed in/on a single crystal semiconductor substrate, such as a silicon semiconductor wafer, by first implanting the substrate with a sufficient dosage of noble gas atoms to inhibit subsequent recrystallization of the semiconductor lattice in the implanted region during subsequent annealing, resulting in the formation of an isolation layer comprising implanted noble gas atoms enmeshed with semiconductor atoms in the substrate which has sufficient resistivity to act as an isolation layer. The preferred noble gases used to form such isolation layers are neon, argon, krypton, and xenon. When neon atoms are implanted, the minimum dosage should be at least about 6.times.10.sup.15 neon atoms/cm.sup.2 to inhibit subsequent recrystallization of the silicon substrate. When argon atoms are implanted, the minimum dosage should be at least about 2.times.10.sup.15 argon atoms/cm.sup.2.
    Type: Grant
    Filed: December 16, 1996
    Date of Patent: March 3, 1998
    Assignee: LSI Logic Corporation
    Inventors: Abraham Yee, Sheldon Aronowitz
  • Patent number: 5717238
    Abstract: A process and resulting product are described for controlling the channeling and/or diffusion of a boron dopant in a P- region forming the lightly doped drain (LDD) region of a PMOS device in a single crystal semiconductor substrate, such as a silicon substrate. The channeling and/or diffusion of the boron dopant is controlled by implanting the region, prior to implantation with a boron dopant, with noble gas ions, such as argon ions, at a dosage at least equal to the subsequent dosage of the implanted boron dopant, but not exceeding an amount equivalent to the implantation of about 3.times.10.sup.14 argon ions/cm.sup.2 into a silicon substrate, whereby channeling and diffusion of the subsequently implanted boron dopant is inhibited without, however, amorphizing the semiconductor substrate.
    Type: Grant
    Filed: July 9, 1996
    Date of Patent: February 10, 1998
    Assignee: LSI Logic Corporation
    Inventors: Sheldon Aronowitz, James Kimball, Yu-Lam Ho, Gobi Padmanabhan, Douglas T. Grider, Chi-Yi Kao
  • Patent number: 5707888
    Abstract: A process and resulting product is described for forming an oxide in a semiconductor substrate which comprises initially implanting the substrate with atoms of a noble gas, then oxidizing the implanted substrate at a reduced temperature, e.g., less than 900.degree. C., to form oxide in the implanted region of the substrate, and then etching the oxidized substrate to remove a portion of the oxide. The resulting oxidation produces a dual layer of oxide in the substrate. The upper layer is an extremely porous and frothy layer of oxide, while the lower layer is a more dense oxide. The upper porous layer of oxide can be selectively removed from the substrate by a mild etch, leaving the more dense oxide layer in the substrate. Further oxide can then be formed adjacent the dense layer of oxide in the substrate, either by oxide deposition over the dense oxide or by growing further oxide beneath the dense oxide layer.
    Type: Grant
    Filed: May 4, 1995
    Date of Patent: January 13, 1998
    Assignee: LSI Logic Corporation
    Inventors: Sheldon Aronowitz, James Kimball
  • Patent number: 5654210
    Abstract: Formation of a barrier region in a single crystal group IV semiconductor substrate at a predetermined spacing from a doped region in the substrate is described to prevent or inhibit migration of dopant materials from an adjacent doped region through the barrier region. By implantation of group IV materials into a semiconductor substrate to a predetermined depth in excess of the depth of a doped region, a barrier region can be created in the semiconductor to prevent migration of the dopants from the doped region through the barrier region. The treatment of the single crystal substrate with the group IV material is carried out at a dosage and energy level sufficient to provide such a barrier region in the semiconductor substrate, but insufficient to result in amorphization (destruction) of the single crystal lattice of the semiconductor substrate.
    Type: Grant
    Filed: May 4, 1995
    Date of Patent: August 5, 1997
    Assignee: LSI Logic Corporation
    Inventors: Sheldon Aronowitz, James Kimball
  • Patent number: 5585286
    Abstract: A process and resulting product are described for controlling the channeling and/or diffusion of a boron dopant in a P- region forming the lightly doped drain (LDD) region of a PMOS device in a single crystal semiconductor substrate, such as a silicon substrate. The channeling and/or diffusion of the boron dopant is controlled by implanting the region, prior to implantation with a boron dopant,, with noble gas ions, such as argon ions, at a dosage at least equal to the subsequent dosage of the implanted boron dopant, but not exceeding an amount equivalent to the implantation of about 3.times.10.sup.13 argon ions/cm.sup.2 into a silicon substrate, whereby channeling and diffusion of the subsequently implanted boron dopant is inhibited without, however, amorphizing the semiconductor substrate.
    Type: Grant
    Filed: August 31, 1995
    Date of Patent: December 17, 1996
    Assignee: LSI Logic Corporation
    Inventors: Sheldon Aronowitz, James Kimball, Yu-Lam Ho, Gobi Padmanabhan, Douglas T. Grider, Chi-Yi Kao
  • Patent number: 5571744
    Abstract: A method for manufacturing CMOS semiconductor devices wherein damage to the active regions of the devices due to the direct implantation of impurities is suppressed. A material is selectively deposited on a semiconductor substrate, the material having a characteristic such that formation of the material occurs on some substances such as silicon and polysilicon, and formation of the material is suppressed on other substances such as silicon dioxide and silicon nitride. Impurities are introduced into the material rather than into the substrate. The impurities are then diffused into the active regions by standard processes such as rapid thermal anneal (RTA) or furnace anneal. The material generally contains germanium, and usually is a polycrystalline silicon-germanium alloy. The diffusion depth of the impurities may be controlled with great precision by manipulating several parameters.
    Type: Grant
    Filed: August 27, 1993
    Date of Patent: November 5, 1996
    Assignee: National Semiconductor Corporation
    Inventors: Esin K. Demirlioglu, Sheldon Aronowitz
  • Patent number: 5538907
    Abstract: A CMOS integrate circuit has improved protection to damage from electrostatic discharge (ESD) events because the circuit is formed with a virtual lateral bipolar transistor submerged in the morphology of the integrated circuit beneath an active circuit element of the circuit, and being formed by impurity atoms implanted into the substrate structure as ions which disperse laterally to form a dispersed charge permeation zone through which surge current from an ESD is conducted safely at a current level sufficiently low that the substrate material of the integrated circuit is not damaged. The integrated circuit may be formed with an intrinsic zener diode having a reverse bias breakdown voltage high enough to not interfere with the normal operation of the integrated circuit, and low enough to allow surge current from an ESD event to safely flow to ground potential.
    Type: Grant
    Filed: May 11, 1994
    Date of Patent: July 23, 1996
    Assignee: LSI Logic Corporation
    Inventors: Sheldon Aronowitz, Rosario Consiglio, Abraham Yee
  • Patent number: 5508211
    Abstract: An integrated circuit structure vertically isolated electrically from the underlying substrate is formed in/on a single crystal semiconductor substrate, such as a silicon semiconductor wafer, by first implanting the substrate with a sufficient dosage of noble gas atoms to inhibit subsequent recrystallization of the semiconductor lattice in the implanted region during subsequent annealing, resulting in the formation of an isolation layer comprising implanted noble gas atoms enmeshed with semiconductor atoms in the substrate which has sufficient resistivity to act as an isolation layer. The preferred noble gases used to form such isolation layers are neon, argon, krypton, and xenon. When neon atoms are implanted, the minimum dosage should be at least about 6.times.10.sup.15 neon atoms/cm.sup.2 to inhibit subsequent recrystallization of the silicon substrate. When argon atoms are implanted, the minimum dosage should be at least about 2.times.10.sup.15 argon atoms/cm.sup.2.
    Type: Grant
    Filed: February 17, 1994
    Date of Patent: April 16, 1996
    Assignee: LSI Logic Corporation
    Inventors: Abraham Yee, Sheldon Aronowitz
  • Patent number: 5504016
    Abstract: The effect of dopant-dopant interaction on diffusion in silicon for a specific set of impurities is modeled. The first step in the modeling process involved quantum chemical calculations. The connection between the atomic scale results and macroscopic behavior was made through the medium for transmission of interactions between dopants. The molecular orbitals of the lattice system comprise that medium; consequently, interactions can be transmitted, with minimal reduction in magnitude, over separations of hundreds of lattice spacings. Macroscopically, additional flux components are generated that modify the conventional expression of Fick's second law. Detailed simulation of boron and phosphorus diffusion in germanium rich regions of silicon illustrate the power of this approach to successfully model and predict the complex behavior exhibited by a particular set of interacting dopant species.
    Type: Grant
    Filed: October 17, 1994
    Date of Patent: April 2, 1996
    Assignee: National Semiconductor Corporation
    Inventor: Sheldon Aronowitz
  • Patent number: 5468974
    Abstract: Dopant distribution and activation in polysilicon is controlled by implanting electrically neutral atomic species which accumulate along polysilicon grain boundaries. Exemplary atomic species include noble gases and Group IV elements other than silicon.
    Type: Grant
    Filed: May 26, 1994
    Date of Patent: November 21, 1995
    Assignee: LSI Logic Corporation
    Inventors: Sheldon Aronowitz, Yen-Hui J. Ku, Yu-Lam Ho
  • Patent number: 5459085
    Abstract: A transistor gate array includes an active transistor region (50a-50n) of transistor gates all oriented in a single direction. Surrounding the active transistor region on all four sides are input/output regions (52a-52d) each containing a row of input/output transistors. All of the I/O devices on all sides of the array are oriented in the same common direction, which is the same direction as the orientation of the active transistor in the active region. This arrangement allows the use of the benefits of high angle ion implantation with fewer ion implant steps. Where some of the transistors are oriented at right angles to others, as in the prior art, four separate directions of high angle ion implantation are required to avoid degradation of electrical properties. With all transistors, including those of the gate array and those of the input/output devices, all oriented in the same direction, only two directions of high angle ion implantation are required.
    Type: Grant
    Filed: May 13, 1994
    Date of Patent: October 17, 1995
    Assignee: LSI Logic Corporation
    Inventors: Nicholas F. Pasen, Aldona M. Butkus, Sheldon Aronowitz
  • Patent number: 5453389
    Abstract: A method for manufacturing bipolar semiconductor devices wherein damage to the active regions of the devices due to the direct implantation of impurities is suppressed. A material is selectively deposited on a semiconductor substrate, the material having a characteristic such that formation of the material occurs on some substances such as silicon and polysilicon, and formation of the material is suppressed on other substances such as silicon dioxide and silicon nitride. Impurities are introduced into the material rather than into the substrate. The impurities are then diffused into the active regions by standard processes such as rapid thermal anneal (RTA) or furnace anneal. The material generally contains germanium, and usually is a polycrystalline silicon-germanium alloy. The diffusion depth of the impurities may be controlled with great precision by manipulating several parameters.
    Type: Grant
    Filed: August 27, 1993
    Date of Patent: September 26, 1995
    Assignee: National Semiconductor, Inc.
    Inventors: Robert J. Strain, Sheldon Aronowitz
  • Patent number: 5441900
    Abstract: A unique approach to suppressing latchup in CMOS structures is described. Atomic species that exhibit midgap levels in silicon and satisfy the criteria for localized action and electrical compatibility can be implanted to suppress the parasitic bipolar behavior which causes latchup. Reduction of minority carrier lifetime can be achieved in critical parasitic bipolar regions that, by CMOS construction are outside the regions of active MOS devices. One way to accomplish this goal is to use the source/drain masks to locally implant the minority carrier lifetime reducer (MCLR) before the source/drain dopants are implanted. This permits the MCLR to be introduced at different depths or even to be different species, of the n and p-channel transistors. Another way to accomplish this goal requires that a blanket MCLR implant be done very early in the process, before isolation oxidation, gate oxidation or active threshold implants are done.
    Type: Grant
    Filed: September 19, 1994
    Date of Patent: August 15, 1995
    Assignee: National Semiconductor Corporation
    Inventors: Constantin Bulucea, Esin Dermirlioglu, Sheldon Aronowitz
  • Patent number: 5384477
    Abstract: A unique approach to suppressing latchup in CMOS structures is described. Atomic species that exhibit midgap levels in silicon and satisfy the criteria for localized action and electrical compatibility can be implanted to suppress the parasitic bipolar behavior Which causes latchup. Reduction of minority carrier lifetime can be achieved in critical parasitic bipolar regions that, by CMOS construction are outside the regions of active MOS devices. One way to accomplish this goal is to use the source/drain masks to locally implant the minority carrier lifetime reducer (MCLR) before the source/drain dopants are implanted. This permits the MCLR to be introduced at different depths or even to be different species, of the n and p-channel transistors. Another way to accomplish this goal requires that a blanket MCLR implant be done very early in the process, before isolation oxidation, gate oxidation or active threshold implants are done.
    Type: Grant
    Filed: March 9, 1993
    Date of Patent: January 24, 1995
    Assignee: National Semiconductor Corporation
    Inventors: Constantin Bulucea, Esin Dermirlioglu, Sheldon Aronowitz
  • Patent number: 5376560
    Abstract: A number of dielectrically isolated single crystal islands are formed by implanting neon or other group Zero ions into a semiconductor substrate, preferably silicon, at a sufficiently high energy to created an amorphized region in the interior of the substrate, without excessively damaging the substrate surface through which the ions pass. The amorphized regions are highly resistive, and are suitable for isolation in some applications. Where better isolation is desired, a dielectric isolation structure is formed as follows. Trenches are formed down into the amorphized regions, and the substrate is heavily oxidized to convert the amorphized regions into buried oxide regions and the island sidewalls into oxide. The islands are made thicker by removing the oxide from the islands' top surfaces and sidewalls, and growing epitaxial silicon over the substrate. Second trenches are formed down to the buried oxide regions, and the substrate is again oxidized to convert the islands' sidewalls to oxide.
    Type: Grant
    Filed: January 24, 1994
    Date of Patent: December 27, 1994
    Assignee: National Semiconductor Corporation
    Inventors: Sheldon Aronowitz, Courtney L. Hart
  • Patent number: 5372952
    Abstract: A number of dielectrically isolated single crystal islands are formed by implanting neon or other group Zero ions into a semiconductor substrate, preferably silicon, at a sufficiently high energy to created an amorphized region in the interior of the substrate, without excessively damaging the substrate surface through which the ions pass. The amorphized regions are highly resistive, and are suitable for isolation in some applications. Where better isolation is desired, a dielectric isolation structure is formed as follows. Trenches are formed down into the amorphized regions, and the substrate is heavily oxidized to convert the amorphized regions into buried oxide regions and the island sidewalls into oxide. The islands are made thicker by removing the oxide from the islands' top surfaces and sidewalls, and growing epitaxial silicon over the substrate. Second trenches are formed down to the buried oxide regions, and the substrate is again oxidized to convert the islands' sidewalls to oxide.
    Type: Grant
    Filed: April 3, 1992
    Date of Patent: December 13, 1994
    Assignee: National Semiconductor Corporation
    Inventors: Sheldon Aronowitz, Courtney L. Hart
  • Patent number: 5357135
    Abstract: Body to drain junction breakdown, due to avalanching in DMOST devices, can be controlled. The invention lowers the electric field gradients in the vicinity of the PN junction. The structure employed to enhance breakdown behavior is specifically applied to a vertical DMOST. The N type doping profile in the vicinity of the body to drain junction is tailored by constructing a P-nu-N-N.sup.+ type diode structure where nu is a low N type impurity concentration region. The N type region is of higher impurity concentration and is more extensive. With the nu region having one-half of the impurity concentration of the N region and an extent of about two microns, the avalanche breakdown voltage is about 27% higher than the conventional PN junction diode. By making the nu region impurity concentration one-fourth that of the N region, the breakdown voltage is 40% higher.
    Type: Grant
    Filed: February 18, 1994
    Date of Patent: October 18, 1994
    Assignee: National Semiconductor Corporation
    Inventors: Sheldon Aronowitz, George P. Walker, Peter Meng, Farrokh Mohammadi, Bhaskar V. S. Gadepally
  • Patent number: 5312766
    Abstract: Germanium is used to significantly enhance the drift mobilities of minority carriers in the channels of N-channel and P-channel metal-oxide-semiconductor (MOS) transistors with silicon substrates. Germanium processing is also used to enhance the source/drain contact conductance for MOS devices. Methods are disclosed for forming the germanium-rich interfacial layer utilizing a germanium implant and wet oxidation or growing a silicon-germanium alloy by molecular beam epitaxy.
    Type: Grant
    Filed: February 7, 1992
    Date of Patent: May 17, 1994
    Assignee: National Semiconductor Corporation
    Inventors: Sheldon Aronowitz, Courtney Hart, Court Skinner
  • Patent number: 5298435
    Abstract: A method of inhibiting dopant diffusion in silicon using germanium is provided. Germanium is distributed in substitutional sites in a silicon lattice to form two regions of germanium interposed between a region where dopant is to be introduced and a region from which dopant is to be excluded, the two germanium regions acting as a dopant diffusion barrier.
    Type: Grant
    Filed: September 3, 1992
    Date of Patent: March 29, 1994
    Assignee: National Semiconductor Corporation
    Inventors: Sheldon Aronowitz, Courtney L. Hart, Sung T. Ahn
  • Patent number: 5296387
    Abstract: Germanium is used to significantly enhance the drift mobilities of minority carriers in the channels of N-channel and P-channel metal-oxide-semiconductor (MOS) transistors with silicon substrates. Germanium processing is also used to enhance the source/drain contact conductance for MOS devices. Methods are disclosed for forming a germanium-rich interfacial layer utilizing a germanium implant and wet oxidation or growing a silicon-germanium alloy by molecular beam epitaxy.
    Type: Grant
    Filed: December 2, 1992
    Date of Patent: March 22, 1994
    Assignee: National Semiconductor Corporation
    Inventors: Sheldon Aronowitz, Courtney Hart