Patents by Inventor Stewart Logie
Stewart Logie 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: 9672935Abstract: One aspect relates to a memory circuit that has a programmable non-volatile memory (NVM) cell configured to generate an NVM output signal indicative of a program state of the NVM cell and to configure a volatile output based on the program state of the NVM cell. The NVM cell comprises a first anti-fuse device, a first select device connected in series with the first anti-fuse device at a first node, and a first pass device. The memory circuit also may have a programmable (independently of the NVM cell) volatile memory (VM) cell configured to receive the NVM output signal at a VM input node and to generate a VM output signal indicative of the program state of the VM cell. The NVM cell may have two NV elements that are separately programmable and are separately selectable via separate access transistors to drive the VM input node.Type: GrantFiled: October 19, 2015Date of Patent: June 6, 2017Assignee: Lattice Semiconductor CorporationInventors: Ronald L Cline, Stewart Logie
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Publication number: 20160111168Abstract: One aspect relates to a memory circuit that has a programmable non-volatile memory (NVM) cell configured to generate an NVM output signal indicative of a program state of the NVM cell and to configure a volatile output based on the program state of the NVM cell. The NVM cell comprises a first anti-fuse device, a first select device connected in series with the first anti-fuse device at a first node, and a first pass device. The memory circuit also may have a programmable (independently of the NVM cell) volatile memory (VM) cell configured to receive the NVM output signal at a VM input node and to generate a VM output signal indicative of the program state of the VM cell. The NVM cell may have two NV elements that are separately programmable and are separately selectable via separate access transistors to drive the VM input node.Type: ApplicationFiled: October 19, 2015Publication date: April 21, 2016Inventors: Ronald L. Cline, Stewart Logie
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Patent number: 7989911Abstract: In one embodiment, an integrated circuit includes a substrate having high voltage transistor regions and low voltage transistor regions. The substrate includes a first trench between and adjacent to the high voltage transistor regions, a second trench between and adjacent to the low voltage transistor regions, and a third trench between the first and second trenches and between and adjacent to a high voltage transistor region and a low voltage transistor region. A thicker silicon dioxide layer lines the first trench and a first portion of the third trench adjacent to a high voltage transistor region. A thinner silicon dioxide layer lines the second trench and a second portion of the third trench adjacent to a low voltage transistor region.Type: GrantFiled: October 28, 2009Date of Patent: August 2, 2011Assignee: Lattice Semiconductor CorporationInventors: Sunil Mehta, Stewart Logie, Steven Fong
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Patent number: 7985656Abstract: A method of manufacturing an integrated circuit includes etching a substrate to create simultaneously a first trench between high voltage transistor regions of the substrate and a second trench between low voltage regions of the substrate. The substrate is then oxidized to form a silicon dioxide layer lining the first and second trenches, the layer having a first thickness. A silicon nitride layer is deposited on the silicon dioxide layer in the first and second trenches. The silicon nitride layer is then etched from the first trench but not from the second trench, thereby exposing the silicon layer in the first trench but not the second trench. The exposed silicon dioxide layer in the first trench is oxidized to increase the thickness of the silicon dioxide layer to a second thickness greater than the first thickness of the unexposed silicon dioxide layer in the second trench. The first and second trenches are then filled with a dielectric material.Type: GrantFiled: October 28, 2009Date of Patent: July 26, 2011Assignee: Lattice Semiconductor CorporationInventors: Sunil Mehta, Stewart Logie, Steven Fong
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Publication number: 20070267715Abstract: Improved shallow trench isolation (STI) techniques are provided for semiconductor devices. For example, in accordance with an embodiment of the present invention, an integrated circuit includes a substrate, a first trench in the substrate, and a second trench in the substrate. A first silicon dioxide liner substantially lines the first trench. A second silicon dioxide liner substantially lines the second trench, wherein the second silicon dioxide liner has a thickness greater than a thickness of the first silicon dioxide liner. A silicon nitride liner is on the first silicon dioxide liner in the first trench but not on the second silicon dioxide liner in the second trench. A dielectric material fills the first and second trenches.Type: ApplicationFiled: May 18, 2006Publication date: November 22, 2007Inventors: Sunil Mehta, Stewart Logie, Steve Fong
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Publication number: 20070111403Abstract: In one embodiment, a polycide fuse is provided that includes: a polysilicon layer; a silicide layer formed on the polysilicon layer; and a silicon nitride layer formed on the silicide layer by RTCVD, the silicon nitride layer having a relatively low hydrogen concentration and relatively low mechanical stress.Type: ApplicationFiled: November 15, 2005Publication date: May 17, 2007Inventors: Chun Jiang, Sunil Mehta, Stewart Logie
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Patent number: 7067883Abstract: A lateral high-voltage junction device for over-voltage protection of an MOS circuit includes a substrate having a first junction region separated from a second junction region by a substrate region. An MOS gate electrode overlies the substrate region and is separated therefrom by a gate dielectric layer. Sidewall spacers reside adjacent to opposing sides of the MOS gate electrode and overlie the substrate region. The substrate region is defined by a junction-free semiconductor region between the first and second junction regions. An input protection circuit employs the lateral high-voltage junction device to transfer voltage transients to a ground node.Type: GrantFiled: October 31, 2003Date of Patent: June 27, 2006Assignee: Lattice Semiconductor CorporationInventor: Stewart Logie
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Patent number: 7024646Abstract: Systems and methods provide electrostatic discharge simulation techniques. For example, a method in accordance with an embodiment of the present invention provides a simulation of electrostatic discharge in integrated circuits. The method may allow for the design of protection circuits and simulating electrostatic discharge events concurrently with the design of the associated electrical circuit.Type: GrantFiled: January 29, 2004Date of Patent: April 4, 2006Assignee: Lattice Semiconductor CorporationInventors: Stewart Logie, Farrokh Kia Omid-Zohoor, Nui Chong
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Publication number: 20050172246Abstract: Systems and methods provide electrostatic discharge simulation techniques. For example, a method in accordance with an embodiment of the present invention provides a simulation of electrostatic discharge in integrated circuits. The method may allow for the design of protection circuits and simulating electrostatic discharge events concurrently with the design of the associated electrical circuit.Type: ApplicationFiled: January 29, 2004Publication date: August 4, 2005Inventors: Stewart Logie, Farrokh Omid-Zohoor, Nui Chong
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Publication number: 20050093069Abstract: A lateral high-voltage junction device for over-voltage protection of an MOS circuit includes a substrate having a first junction region separated from a second junction region by a substrate region. An MOS gate electrode overlies the substrate region and is separated therefrom by a gate dielectric layer. Sidewall spacers reside adjacent to opposing sides of the MOS gate electrode and overlie the substrate region. The substrate region is defined by a junction-free semiconductor region between the first and second junction regions. An input protection circuit employs the lateral high-voltage junction device to transfer voltage transients to a ground node.Type: ApplicationFiled: October 31, 2003Publication date: May 5, 2005Inventor: Stewart Logie
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Patent number: 6841447Abstract: A semiconductor device having an EEPROM memory cell includes a substrate having a principal surface and an isolation region having an inner edge surface bounding the tunnel region at the principal surface. The isolation region forms a perimeter of the tunnel region. A capacitor plate overlies the tunnel region and substantially the entire perimeter of the tunnel region. A tunnel dielectric layer overlies the tunnel region and separates the capacitor plate from the tunnel dielectric layer. The edges of the capacitor plate are displaced away from the tunnel dielectric layer to avoid a loss of tunneling current as a result of edge degradation with repeated programming and erasing of the EEPROM memory device. A process for fabrication of the device is also provided.Type: GrantFiled: August 30, 2002Date of Patent: January 11, 2005Assignee: Lattice Semiconductor CorporationInventors: Stewart Logie, Sunil D. Mehta
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Patent number: 6737702Abstract: A zero power memory cell includes first and second NMOS transistors and a PMOS transistor, wherein the first NMOS transistor and first PMOS transistor each include a three-implant channel region, and wherein the second NMOS transistor further includes a two-implant channel region.Type: GrantFiled: July 24, 2003Date of Patent: May 18, 2004Assignee: Lattice Semiconductor CorporationInventors: Chun Jiang, Sunil Mehta, Stewart Logie
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Patent number: 6660579Abstract: A method for forming a three transistor zero power memory cell including a p-channel sense transistor, an n-channel write transistor, and an n-channel sense transistor including: implanting a p-type impurity into a p-type substrate in which a n-channel high voltage transistor will be formed; implanting an n-type impurity into an n-type well in a p-type substrate in which a p-channel high voltage transistor will be formed; forming a mask to allow implants to occur to p-channel devices; performing a series of n-type dopant implants into the substrate where the p-channel transistors will be formed; growing a high voltage gate oxide; forming a mask to allow implants to occur to n-channel devices, said mask blocking implants to said n-channel sense transistor; and performing a series of p-type implants into the substrate where the n-channel devices will be formed. In addition, a memory cell which may include a first NMOS transistor having a source, drain and gate, and a first PMOS transistor is disclosed.Type: GrantFiled: April 24, 2002Date of Patent: December 9, 2003Assignee: Lattice Semiconductor Corp.Inventors: Chun Jiang, Sunil Mehta, Stewart Logie
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Patent number: 6627947Abstract: A non-volatile memory cell at least partially formed in a semiconductor substrate. The cell comprises a first transistor comprising a high voltage NMOS transistor having a first active region and a second active region; a second transistor sharing said second active region and having a third active region in said substrate; an active control gate region formed in said substrate; a polysilicon layer having a first portion forming a gate for said first transistor, and a second portion forming gate for said second transistor and a floating gate overlying said active control gate region. In one embodiment, an oxynitride separates said second portion and said active control gate region.Type: GrantFiled: August 22, 2000Date of Patent: September 30, 2003Assignee: Lattice Semiconductor CorporationInventors: Yongzhong Hu, Jein Chen Young, Stewart Logie
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Patent number: 6570212Abstract: A non-volatile memory cell at least partially formed in a semiconductor substrate, comprising a first avalanche injection element having a first active region of a first conductivity type and a second active region of a second conductivity type, separated by a channel region of said second conductivity type; a second avalanche injection element having a third active region of said second conductivity type and sharing said second active region with said first avalanche injection element, the second avalanche injection element having a channel region of said first conductivity type; and a common floating gate at least partially overlying said first and second avalanche injection elements. In a further embodiment, the first avalanche element has an N+/P junction, the second avalanche element has a P+/N junction, and the floating gate capacitively coupled to the first and second avalanche elements.Type: GrantFiled: May 24, 2000Date of Patent: May 27, 2003Assignee: Lattice Semiconductor CorporationInventors: Sunil D. Mehta, Steven Fong, Stewart Logie
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Patent number: 5742542Abstract: An improved EEPROM structure is provided which has a longer data retention period. This is achieved by utilizing only positive charges to store data on the floating gate. The EEPROM structure includes a write select transistor (112), a read select transistor (120), and a floating gate sense transistor (126). The source of the write select transistor is capacitively coupled to the floating gate of the floating gate sense transistor via a tunnel oxide layer (145). The floating gate of the floating gate sense transistor is also capacitively coupled to a control gate line (CG) via a gate oxide layer (153). The sense transistor is formed as an enhancement transistor so as to allow the EEPROM structure to be operated in a region where the floating gate potential is positive for both programmed and erased conditions, thereby using only the positive charges to store data.Type: GrantFiled: July 3, 1995Date of Patent: April 21, 1998Assignee: Advanced Micro Devices, Inc.Inventors: Jonathan Lin, Stewart Logie
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Patent number: 4924278Abstract: A single layer of polycrystalline silicon (poly-Si) is used in an EEPROM structure, which obviates the need to form a separate control gate and floating gate. The EEPROM utilizes three separate NMOS transistors: a write transistor, a read transistor, and a sense transistor. A thin tunnel oxide layer separates the N+ source region of the write transistor from an N doped poly-Si layer and capacitively couples the source region to the poly-Si layer. The poly-Si layer extends over the N+ source region of the sense transistor and is capacitively coupled to the source region of the sense transistor via a thin gate oxide insulating layer which is thicker than the oxide layer comprising the tunnel oxide layer. This poly-Si layer continues to extend over a channel region separating the N+ source and N+ drain regions of the sense transistor, the poly-Si layer being separated from the channel via the thin gate oxide insulating layer. The drain of the sense transistor also acts as the source of the read transistor.Type: GrantFiled: November 15, 1988Date of Patent: May 8, 1990Assignee: Advanced Micro Devices, Inc.Inventor: Stewart Logie