Patents by Inventor Ranbir Singh
Ranbir Singh 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: 6252270Abstract: A programmable semiconductor device and a method of manufacturing the same. The device includes: (1) a substrate composed at least in part of silicon, (2) a dielectric layer located over the substrate and (3) a control gate located over the dielectric layer wherein the dielectric layer contains a substantial concentration of an isotope of hydrogen.Type: GrantFiled: April 28, 1997Date of Patent: June 26, 2001Assignee: Agere Systems Guardian Corp.Inventors: Richard W. Gregor, Isik C. Kizilyalli, Ranbir Singh
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Patent number: 6222764Abstract: An electrically erasable memory device includes a substrate and a plurality of single poly layer memory cells in the substrate. Each single poly layer memory cell includes a first MOS transistor in a first region in the substrate and spaced apart source and drain regions. Each single poly layer memory cell further includes a capacitor having a first electrode overlying a second region in the substrate and an insulating layer therebetween, and a third region in the second region defining a second electrode. An erasing circuit selectively erases the single poly layer memory cell by supplying a first voltage reference of a first polarity to the spaced apart source and drain regions, a second voltage reference of a second polarity to the first region, and a third voltage reference of the second polarity to the second electrode of the capacitor.Type: GrantFiled: December 13, 1999Date of Patent: April 24, 2001Assignee: Agere Systems Guardian Corp.Inventors: Patrick J. Kelley, Chung Wai Leung, Ranbir Singh
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Patent number: 6218254Abstract: A method of fabricating a self-aligned bipolar junction transistor in a semiconductor structure having a first layer of silicon carbide generally having a first conductivity type and a second layer of silicon carbide generally having a second conductivity type, opposite to the first conductivity type. The method comprises forming a pillar in the second silicon carbide layer, the pillar having a side wall and defining an adjacent horizontal surface on the second layer, forming a dielectric layer having a predetermined thickness on the second semiconductor layer, including the side wall and the horizontal surface. After formation of the dielectric layer, the dielectric layer on a portion of the horizontal surface adjacent the side wall is anisotropically etched while at least a portion of the dielectric layer remains on the side wall, thereby exposing a portion of the horizontal surface.Type: GrantFiled: September 22, 1999Date of Patent: April 17, 2001Assignee: Cree Research, Inc.Inventors: Ranbir Singh, Anant K. Agarwal, Sei-Hyung Ryu
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Patent number: 6215013Abstract: A method for the preparation of alkene phosphonic acids and salts thereof, such as VDPA (vinylidene diphosphonic acid) is disclosed. The products can be produced in a stable, substantially pure form and in high yield. The method includes the azeotropic removal of water from salts of &agr;-hydroxy-alkane diphosphonic acid dimer or corresponding acids thereof, and the pyrolysis of the dehydrated reactant at a temperature of from 170° C. to 300° C. There may be included a step to convert anhydrides which have been formed during the pyrolysis. The method may include the use of heat transfer agents and/or bases, and may be carried out at elevated or reduced pressure.Type: GrantFiled: September 5, 2000Date of Patent: April 10, 2001Assignee: Rhodia Consumer Specialties LimitedInventors: Gary Woodward, Timothy Kevin Brierley, Ranbir Singh Padda, John Christopher Harris, Aidan Michael Hayes
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Patent number: 6191980Abstract: A single-poly flash memory cell has a control device, a switch device, and an erase device, all of which share a common polysilicon floating gate which is designed to retain charge in the programmed memory cell. The memory cell is erased by applying an erase voltage to the tub of the erase device to cause tunneling across the oxide layer separating the floating gate from the rest of the erase device structure. Since a typical tub-to-source/drain breakdown voltage (e.g., 15 volts) is greater than a typical erase voltage (e.g., 10 volts), the memory cell can be safely erased without risking the junction breakdowns that are associated with other prior art single-poly memory cell designs for deep sub-micron technologies (e.g., 0.25-micron and lower).Type: GrantFiled: May 31, 2000Date of Patent: February 20, 2001Assignee: Lucent Technologies, Inc.Inventors: Patrick J. Kelley, Ross A. Kohler, Chung W. Leung, Richard J. McPartland, Ranbir Singh
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Patent number: 6174786Abstract: A method of shallow trench isolation by forming a trench in a semiconductor device comprises the steps of forming an oxide layer; forming a mask layer; anisotropically etching the mask layer; forming a second oxide layer; forming a cap layer; forming rounded end caps adjacent the mask; and transferring the rounding of the caps to the top corners of the trench. The oxide layer is formed over a substrate of the semiconductor device. The mask layer is formed over the oxide layer. The mask layer is then anisotropically etched to form the mask and an opening in the mask. The opening in the mask exposes the substrate, and the width of the opening is greater than the width of the trench. Blanket etching the cap layer forms the rounded end caps. The rounded end caps are adjacent to the mask on opposite ends of the opening, and the distance between the end caps is about equal to the width of the trench. The trench is formed by plasma etching the trench.Type: GrantFiled: November 23, 1999Date of Patent: January 16, 2001Assignee: Lucent Technologies, Inc.Inventors: Patrick J. Kelley, Ranbir Singh, Larry B. Fritzinger, Cynthia C. Lee, John Simon Molloy
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Patent number: 6168995Abstract: A method of fabricating a novel split gate memory cell comprises forming a tunnel oxide layer on a silicon substrate, forming a first conductive layer over said tunnel oxide layer, etching a trench in said conductive layer to divide said conductive layer into two separate layers with a space therebetween, one such layer to become a first gate electrode and the other separate layer to become a floating gate electrode of the device, forming a dielectric layer over the exposed surfaces, and depositing a second conductive layer which will become a second control gate electrode over said dielectric layer.Type: GrantFiled: December 14, 1999Date of Patent: January 2, 2001Assignee: Lucent Technologies Inc.Inventors: Patrick J. Kelley, Chung Wai Leung, Ranbir Singh
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Patent number: 6121633Abstract: A MOS bipolar transistor is provide which includes a silicon carbide npn bipolar transistor formed on a bulk single crystal n-type silicon carbide substrate and having an n-type drift layer a p-type base layer. Preferably the base layer is formed by epitaxial growth and formed as a mesa. A silicon carbide nMOSFET is formed adjacent the npn bipolar transistor such that a voltage applied to the gate of the nMOSFET causes the npn bipolar transistor to enter a conductive state. The nMOSFET has a source and a drain formed so as to provide base current to the npn bipolar transistor when the bipolar transistor is in a conductive state. Also included are means for converting electron current flowing between the source and the drain into hole current for injection into the p-type base layer. Means for reducing field crowding associated with an insulating layer of said nMOSFET may also be provided.Type: GrantFiled: May 21, 1998Date of Patent: September 19, 2000Assignee: Cree Research, Inc.Inventors: Ranbir Singh, John W. Palmour
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Patent number: 6107142Abstract: Silicon carbide power devices are fabricated by implanting p-type dopants into a silicon carbide substrate through an opening in a mask, to form a deep p-type implant. N-type dopants are implanted into the silicon carbide substrates through the same opening in the mask, to form a shallow n-type implant relative to the p-type implant. Annealing is then performed at temperature and time that is sufficient to laterally diffuse the deep p-type implant to the surface of the silicon carbide substrate surrounding the shallow n-type implant, without vertically diffusing the p-type implant to the surface of the silicon carbide substrate through the shallow n-type implant. Accordingly, self-aligned shallow and deep implants may be performed by ion implantation, and a well-controlled channel may be formed by the annealing that promotes significant diffusion of the p-type dopant having high diffusivity, while the n-type dopant having low diffusivity remains relatively fixed.Type: GrantFiled: June 8, 1998Date of Patent: August 22, 2000Assignee: Cree Research, Inc.Inventors: Alexander Suvorov, John W. Palmour, Ranbir Singh
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Patent number: 6100169Abstract: Silicon carbide power devices are fabricated by masking the surface of a silicon carbide substrate to define an opening at the substrate, implanting p-type dopants into the silicon carbide substrate through the opening at implant energy and dosage that form a deep p-type implant, and implanting n-type dopants into the silicon carbide substrate through the opening at implant energy and dosage that form a shallow n-type implant relative to the deep p-type implant. The deep p-type implant and the shallow n-type implant are annealed at less than 1650.degree. C., but preferably more than about 1500.degree.. The annealing preferably takes place for between about five minutes and about thirty minutes. Ramp-up time from room temperature to the anneal temperature is also controlled to be less than about one hundred minutes but more than about thirty minutes. Ramp-down time after annealing is also controlled by decreasing the temperature from the annealing temperature to below about 1500.degree. C.Type: GrantFiled: June 8, 1998Date of Patent: August 8, 2000Assignee: Cree, Inc.Inventors: Alexander Suvorov, John W. Palmour, Ranbir Singh
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Patent number: 6040616Abstract: The present invention provides, for use in an integrated circuit structure having a prior level that includes a foundation dielectric formed over a conductive polycrystalline material, a capacitor comprising first and second electrodes having a capacitor dielectric formed therebetween. The first electrode is formed immediately over the prior level and extends beyond a common area of the first and second electrodes and connects the capacitor to the prior level outside of the common area. The capacitor is free of a direct electrical contact with the prior level; that is, the capacitor is not connected to the prior level by a window or other interconnect structure that extends directly from the capacitor itself within the common area. Electrical connection of the capacitor to the prior level is made outside the common area of the capacitor.Type: GrantFiled: August 12, 1997Date of Patent: March 21, 2000Assignee: Lucent Technologies Inc.Inventors: Donald C. Dennis, Joseph R. Radosevich, Ranbir Singh
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Patent number: 6011279Abstract: A field controlled bipolar switch having a bulk single crystal silicon carbide substrate of a first conductivity type having an upper surface and a lower surface. A first epitaxial layer of a second conductivity type silicon carbide is formed upon the upper surface of the substrate. A second epitaxial layer of the second conductivity type silicon carbide is formed on the first epitaxial layer of silicon carbide. A plurality of regions of a third conductivity type silicon carbide are formed in the second epitaxial layer to form a gate grid in the second epitaxial layer. A third epitaxial layer of the second conductivity type silicon carbide is formed on the second epitaxial layer and a fourth epitaxial layer of the second conductivity type silicon carbide is formed upon the third epitaxial layer. The fourth epitaxial layer has a higher carrier concentration than is present in the first, second and third epitaxial layers.Type: GrantFiled: April 30, 1997Date of Patent: January 4, 2000Assignee: Cree Research, Inc.Inventors: Ranbir Singh, John W. Palmour
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Patent number: 5969378Abstract: A MOS bipolar transistor is provided which includes a silicon carbide npn bipolar transistor formed on a bulk single crystal n-type silicon carbide substrate and having an n-type drift layer and p-type base layer. A silicon carbide nMOSFET is formed adjacent the npn bipolar transistor such that a voltage applied to the gate of the nMOSFET causes the npn bipolar transistor to enter a conductive state. The nMOSFET has a source and a drain formed so as to provide base current to the npn bipolar transistor when the bipolar transistor is in a conductive state. Also provide are means for converting electrons flowing between the source and the drain into holes for injection into the p-type base layer. Unit cells and methods of forming such devices are also provided.Type: GrantFiled: July 10, 1997Date of Patent: October 19, 1999Assignee: Cree Research, Inc.Inventor: Ranbir Singh
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Patent number: 5851870Abstract: A novel capacitor design for use in semiconductor integrated circuits is disclosed. The capacitor includes a metal-dielectric-metal stack formed within a window and upon a conductive substrate. Contact to the top plate of the capacitor is through a window within a window, while contact to the bottom plate is achieved by a guard ring which contacts the conductive substrate.Type: GrantFiled: May 9, 1996Date of Patent: December 22, 1998Assignee: Lucent Technologies Inc.Inventors: Dayo Alugbin, Chung Wai Leung, Joseph Rudolph Radosevich, Ranbir Singh, Daniel Mark Wroge
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Patent number: 5831288Abstract: A silicon carbide (SiC) metal-insulator semiconductor field effect transistor having a u-shaped gate trench and an n-type SiC drift layer is provided. A p-type region is formed in the SiC drift layer and extends below the bottom of the u-shaped gate trench to prevent field crowding at the corner of the gate trench. A unit cell of a metal-insulator semiconductor transistor is provided having a bulk single crystal SiC substrate of n-type conductivity SiC, a first epitaxial layer of n-type SiC and a second epitaxial layer of p-type SiC. First and second trenches extend downward through the second epitaxial layer and into the first epitaxial layer with a region of n-type SiC between the trenches. An insulator layer is formed in the first trench with the upper surface of the insulator on the bottom of the trench below the second epitaxial layer. A region of p-type SiC is formed in the first epitaxial layer below the second trench.Type: GrantFiled: September 29, 1997Date of Patent: November 3, 1998Assignee: Cree Research, Inc.Inventors: Ranbir Singh, John W. Palmour
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Patent number: 5825073Abstract: A method for making a metal-to-metal capacitor for an integrated circuit includes forming a layer of titanium/titanium nitride on a polysilicon which has been patterned with interlevel dielectrics. A capacitor dielectric is then deposited, followed by patterning with photoresist to delineate the capacitor, etching to remove extraneous dielectric, deposition of aluminum, further patterning and etching to define the capacitor and access area, and removal of photoresist.Type: GrantFiled: May 27, 1997Date of Patent: October 20, 1998Assignee: Lucent Technologies, Inc.Inventors: Joseph Rudolph Radosevich, Ranbir Singh
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Patent number: 5721445Abstract: An apparatus and method for providing improved latch-up immunity in a semiconductor device such as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. An exemplary apparatus includes a first region of semiconductor material of a first conductivity type, a well of semiconductor material formed in the first region and having a second conductivity type opposite to the first conductivity type, a first MOS transistor formed in the well and including a source region and a drain region formed of semiconductor material of the first conductivity type, and a second MOS transistor formed in the first region and having a source region and a drain region formed of semiconductor material of the second conductivity type. A conductive material or other suitable routing means is connected between the source region of one of the first or second MOS transistors and a corresponding voltage supply input of the device.Type: GrantFiled: March 2, 1995Date of Patent: February 24, 1998Assignee: Lucent Technologies Inc.Inventors: Ranbir Singh, Morgan Jones Thoma
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Patent number: 5719409Abstract: A silicon carbide (SIC) metal-insulator semiconductor field effect transistor having a u-shaped gate trench and an n-type SiC drift layer is provided. A p-type region is formed in the SiC drift layer and extends below the bottom of the u-shaped gate trench to prevent field crowding at the corner of the gate trench. A unit cell of a metal-insulator semiconductor transistor is provided having a bulk single crystal SiC substrate of n-type conductivity SiC, a first epitaxial layer of n-type SiC and a second epitaxial layer of p-type SiC. First and second trenches extend downward through the second epitaxial layer and into the first epitaxial layer with a region of n-type SiC between the trenches. An insulator layer is formed in the first trench with the upper surface of the insulator on the bottom of the trench below the second epitaxial layer. A region of p-type SiC is formed in the first epitaxial layer below the second trench.Type: GrantFiled: June 6, 1996Date of Patent: February 17, 1998Assignee: Cree Research, Inc.Inventors: Ranbir Singh, John W. Palmour
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Patent number: 5654581Abstract: An integrated circuit with a capacitor includes a conductive substrate, a layer of field dielectric formed on the conductive substrate, a layer of conductive metal or conductive polycrystalline silicon formed on the field dielectric, and first and second laterally spaced apart layers of conductive material formed on the conductive metal or polycrystalline silicon. Each spaced apart layer preferably includes a layer of titanium nitride disposed over a layer of titanium. A layer of capacitor dielectric is deposited on the first of the spaced apart layers, and metal is deposited over the capacitor dielectric and the second layer of conductive material.Type: GrantFiled: June 6, 1995Date of Patent: August 5, 1997Assignee: Lucent Technologies Inc.Inventors: Joseph Rudolph Radosevich, Ranbir Singh
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Patent number: 5576240Abstract: A method for making a metal-to-metal capacitor for an integrated circuit includes forming a layer of titanium/titanium nitride on a polysilicon which has been patterned with interlevel dielectrics. A capacitor dielectric is then deposited, followed by patterning with photoresist to delineate the capacitor, etching to remove extraneous dielectric, deposition of aluminum, further patterning and etching to define the capacitor and access area, and removal of photoresist.Type: GrantFiled: December 9, 1994Date of Patent: November 19, 1996Assignee: Lucent Technologies Inc.Inventors: Joseph R. Radosevich, Ranbir Singh