Patents by Inventor Carlos Paz de Araujo
Carlos Paz de Araujo 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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Publication number: 20050180220Abstract: A device and method of reading a ferroelectric memory, including providing a ferroelectric memory including a ferroelectric memory cell, a charge integrator, and a bit line connecting the ferroelectric memory cell and the charge integrator. Pulses are applied to the ferroelectric memory cell, where each of the pulses are of a value lower than that which will destroy data stored in the memory cell. Output voltage values from the ferroelectric memory cell are accumulated by the charge integrator in response to each pulse. The output of the charge integrator may be read to determine whether the datum value stored in the memory cell is a logic high or low value. In one embodiment, the output of the charge integrator is read at a predetermined time after starting the pulses.Type: ApplicationFiled: January 6, 2005Publication date: August 18, 2005Applicants: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Zheng Chen, Carlos Paz de Araujo, Larry McMillan
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Patent number: 6924997Abstract: A ferroelectric memory 636 includes a group of memory cells (645, 12, 201, 301, 401, 501), each cell having a ferroelectric memory element (44, 218, etc.), a drive line (122, 322, 422, 522 etc.) on which a voltage for writing information to the group of memory cells is placed, a bit line (25, 49, 125, 325, 425, 525, etc.) on which information to be read out of the group of memory cells is placed, a preamplifier (20, 42, 120, 320, 420, etc.) between the memory cells and the bit line, a set switch (14, 114, 314, 414, 514, etc.) connected between the drive line and the memory cells, and a reset switch (16, 116, 316, 416, 516, etc.) connected to the memory cells in parallel with the preamplifier. The memory is read by placing a voltage less than the coercive voltage of the ferroelectric memory element across a memory element. Prior to reading, noise from the group of cells is discharged by grounding both electrodes of the ferroelectric memory element.Type: GrantFiled: September 25, 2001Date of Patent: August 2, 2005Assignees: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Zheng Chen, Vikram Joshi, Myoungho Lim, Carlos A. Paz de Araujo, Larry D. McMillan, Yoshihisa Kato, Tatsuo Otsuki, Yasuhiro Shimada
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Publication number: 20050094457Abstract: A ferroelectric memory includes a group of memory cells, each cell having a ferroelectric memory element, a drive line on which a voltage for writing information to the group of memory cells is placed, and a bit line on which information to be read out of the group of memory cells is placed. The memory is read by placing a voltage less than the coercive voltage of the ferroelectric memory element across a memory element. A preamplifier is connected between the memory cells and the bit line. A set switch is connected between the drive line and the memory cells, and a reset switch is connected to the memory cells in parallel with the preamplifier. Prior to reading, noise from the group of cells is discharged by grounding both electrodes of the ferroelectric memory element.Type: ApplicationFiled: April 28, 2003Publication date: May 5, 2005Applicant: Symetrix CorporationInventors: Zheng Chen, Vikram Joshi, Narayan Solayappan, Carlos Paz de Araujo, Larry McMillan
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Publication number: 20050072925Abstract: A pyrometer cell comprises a first ferroelectric capacitor, a second ferroelectric capacitor, and a difference circuit for determining the difference between the polarization charge, voltage, or current between the first and second ferroelectric capacitors. The cell is pulsed a plurality of times and an integrator circuit connected to the difference circuit provides an enhanced output signal representative of the integrated difference. An infrared imager is formed by an array of the pyrometer cells, with one ferroelectric capacitor in each cell exposed to an infrared source and the other ferroelectric capacitor not exposed to the infrared source.Type: ApplicationFiled: October 6, 2004Publication date: April 7, 2005Applicants: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Zheng Chen, Carlos Paz de Araujo, Jolanta Celinska, Larry McMillan
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Publication number: 20050073876Abstract: A non-volatile SRAM memory comprising a plurality of memory cells, each memory cell including a SRAM memory cell portion and a ferroelectric memory cell portion including a ferroelectric element, the ferroelectric memory cell portion including a switch system for permitting the ferroelectric element to be isolated from the ferroelectric elements in all other memory cells.Type: ApplicationFiled: October 7, 2004Publication date: April 7, 2005Applicants: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Zheng Chen, Carlos Paz de Araujo, Larry McMillan
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Patent number: 6867452Abstract: A high dielectric constant insulator including a thin film of a metal oxide selected from the group consisting of tungsten-bronze-type oxides, pyrochlore-type oxides, and combinations of Bi2O3 with an oxide selected from the group consisting of perovskites and pyrochlore-type oxides. An embodiment contains metal oxides represented by the general stoichiometric formulas AB2O6, A2B2O7 and A2Bi2B2O10, wherein A represents A-site atoms selected from the group of metals consisting of Ba, Bi, Sr, Pb, Ca, K, Na and La; and B represents B-site atoms selected from the group of metals consisting of Ti, Zr, Ta, Hf, Mo, W and Nb. Preferably, the metal oxides are (BaxSr1?x)(TayNb1?y)2O6, where 0?y?1.0 and 0?y?1.0; (BaxSr1?x)2(TayNb1?y)2O7, where 0?x?1.0 and 0?y?1.0; and (BaxSr1?x)2Bi2(TayNb1?y)2O10, where 0?x?1.0 and 0?y?1.0. Thin films according to the invention have a relative dielectric constant ?40, and preferably about 100. The value of Vcc in the metal oxides of the invention is close to zero.Type: GrantFiled: October 23, 2002Date of Patent: March 15, 2005Assignees: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Shinichiro Hayashi, Vikram Joshi, Narayan Solayappan, Joseph D. Cuchiaro, Carlos A. Paz de Araujo
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Patent number: 6864146Abstract: Integrated circuit capacitors in which the capacitor dielectric is a thin film of BST having a grain size smaller than 200 nanometers formed above a silicon germanium substrate. Typical grain sizes are 40 nm and less. The BST is formed by deposition of a liquid precursor by a spin-on process. The original liquid precursor includes an alkoxycarboxylate dissolved in 2-methoxyethanol and a xylene exchange is performed just prior to spinning. The precursor is dried in air at a temperature of about 400° C. and then furnace annealed in oxygen at a temperature of between 600° C. and 850° C.Type: GrantFiled: August 28, 2003Date of Patent: March 8, 2005Assignees: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Carlos A. Paz de Araujo, Masamichi Azuma, Larry D. McMillan, Koji Arita
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Patent number: 6830623Abstract: A plurality of liquids, the flow of each controlled by a volumetric flowrate controller, are mixed in a mixer to form a final precursor that is misted and then deposited on a substrate. A physical property of precursor liquid is adjusted by adjusting the volumetric flowrate controllers, so that when precursor is applied to substrate and treated, the resulting thin film of solid material has a smooth and planar surface. Typically the physical property is the viscosity of the precursor, which is selected to be relatively low, in the range of 1-2 centipoise.Type: GrantFiled: March 12, 2002Date of Patent: December 14, 2004Assignees: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Shinichiro Hayashi, Larry D. McMillan, Carlos A. Paz de Araujo
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Patent number: 6831313Abstract: A ferroelectric memory (436) includes a plurality of memory cells (73, 82, 100) each containing a ferroelectric thin film (15) including a microscopically composite material having a ferroelectric component (18) and a dielectric component (19), the dielectric component being a different chemical compound than the ferroelectric component. The dielectric component is preferably a fluxor, i.e., a material having a higher crystallization velocity than the ferroelectric component. The addition of the fluxor permits a ferroelectric thin film to be crystallized at a temperature of between 400° C. and 550° C.Type: GrantFiled: July 22, 2003Date of Patent: December 14, 2004Assignees: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Kiyoshi Uchiyama, Carlos A. Paz de Araujo, Vikram Joshi, Narayan Solayappan, Jolanta Celinska, Larry D. McMillan
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Publication number: 20040232468Abstract: A hydrogen diffusion barrier in an integrated circuit is located to inhibit diffusion of hydrogen to a thin film of a metal oxide, such as a ferroelectric layered superlattice material, in an integrated circuit. The hydrogen diffusion barrier comprises at least one of the following chemical compounds: strontium tantalate, bismuth tantalate, tantalum oxide, titanium oxide, zirconium oxide and aluminum oxide. The hydrogen barrier layer is amorphous and is made by a MOCVD process at a temperature of 450° C. or less. A supplemental hydrogen barrier layer comprising a material selected from the group consisting of silicon nitride and a crystalline form of one of said hydrogen barrier layer materials is formed adjacent to said hydrogen diffusion barrier.Type: ApplicationFiled: June 21, 2004Publication date: November 25, 2004Applicant: Symetrix CorporationInventors: Narayan Solayappan, Jolanta Celinska, Vikram Joshi, Carlos A. Paz de Araujo, Larry D. McMillan
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Patent number: 6815223Abstract: A precursor for forming a thin film of layered superlattice material is applied to an integrated circuit substrate. The precursor coating is heated using rapid thermal processing (RTP) with a ramping rate of 100° C./second at a hold temperature in a range of from 500° C. to 900° C. for a cumulative heating time not exceeding 30 minutes, and preferably less than 5 minutes. In fabricating a ferroelectric memory cell, the coating is heated in oxygen using RTP, then a top electrode layer is formed, and then the substrate including the coating is heated using RTP in oxygen or in nonreactive gas after forming the top electrode layer. The thin film of layered superlattice material preferably comprises strontium bismuth tantalate or strontium bismuth tantalum niobate, and preferably has a thickness in a range of from 25 nm to 120 nm. The process of fabricating a thin film of layered superlattice material typically has a thermal budget value not exceeding 960,000° C.Type: GrantFiled: November 22, 2002Date of Patent: November 9, 2004Assignee: Symetrix CorporationInventors: Jolanta Celinska, Vikram Joshi, Narayan Solayappan, Myoungho Lim, Larry D. McMillan, Carlos A. Paz de Araujo
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Publication number: 20040211998Abstract: An integrated circuit includes a layered superlattice material including one or more of the elements cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. These elements may either be A-site elements or superlattice generator elements in the layered superlattice material. In one embodiment, one or more of these elements substitute for bismuth in a bismuth layered material. They also are preferably used in combination with one or more of the following elements: strontium, calcium, barium, bismuth, cadmium, lead, titanium, tantalum, hafnium, tungsten, niobium, zirconium, bismuth, scandium, yttrium, lanthanum, antimony, chromium, thallium, oxygen, chlorine, and fluorine. Some of these materials are ferroelectrics that crystallize at relatively low temperatures and are applied in ferroelectric non-volatile memories.Type: ApplicationFiled: May 20, 2004Publication date: October 28, 2004Applicant: Symetrix CorporationInventors: Carlos A. Paz de Araujo, Larry D. McMillan, Narayan Solayappan
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Patent number: 6787181Abstract: A method of forming a Bi-layered superlattice material on a substrate using chemical vapor deposition of a precursor solution of trimethylbismuth and a metal compound dissolved in an organic solvent. The precursor solution is heated and vaporized prior to deposition of the precursor solution on an integrated circuit substrate by chemical vapor deposition. No heating steps including a temperature of 650° C. or higher are used.Type: GrantFiled: October 26, 2001Date of Patent: September 7, 2004Assignees: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Kiyoshi Uchiyama, Narayan Solayappan, Carlos A. Paz de Araujo
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Patent number: 6781184Abstract: A hydrogen diffusion barrier in an integrated circuit is located to inhibit diffusion of hydrogen to a thin film of a metal oxide, such as a ferroelectric layered superlattice material, in an integrated circuit. The hydrogen diffusion barrier comprises at least one of the following chemical compounds: strontium tantalate, bismuth tantalate, tantalum oxide, titanium oxide, zirconium oxide and aluminum oxide. The hydrogen barrier layer is amorphous and is made by a MOCVD process at a temperature of 450° C. or less. A supplemental hydrogen barrier layer comprising a material selected from the group consisting of silicon nitride and a crystalline form of one of said hydrogen barrier layer materials is formed adjacent to said hydrogen diffusion barrier.Type: GrantFiled: November 29, 2001Date of Patent: August 24, 2004Assignee: Symetrix CorporationInventors: Narayan Solayappan, Jolanta Celinska, Vikram Joshi, Carlos A. Paz de Araujo, Larry D. McMillan
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Publication number: 20040129987Abstract: A ferroelectric memory (436) includes a plurality of memory cells (73, 82, 100) each containing a ferroelectric thin film (15) including a microscopically composite material having a ferroelectric component (18) and a dielectric component (19), the dielectric component being a different chemical compound than the ferroelectric component. The dielectric component is preferably a fluxor, i.e., a material having a higher crystallization velocity than the ferroelectric component. The addition of the fluxor permits a ferroelectric thin film to be crystallized at a temperature of between 400° C. and 550° C.Type: ApplicationFiled: July 22, 2003Publication date: July 8, 2004Inventors: Kiyoshi Uchiyama, Carlos A. Paz de Araujo, Vikram Joshi, Narayan Solayappan, Jolanta Celinska, Larry D. McMillan
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Publication number: 20040129961Abstract: A three-dimensional (“3-D”) memory capacitor comprises a bottom electrode, a ferroelectric thin film, and a top electrode that conform to a 3-D surface of an insulator layer. The capacitance area is greater than the horizontal footprint area of the capacitor. Preferably, the footprint of the capacitor is less than 0.2 nm2, and the corresponding capacitance area is typically in a range of from 0.4 nm2 to 1.0 nm2 The ferroelectric thin film preferably has a thickness not exceeding 60 nm. A capacitor laminate including the bottom electrode, ferroelectric thin film, and the top electrode preferably has a thickness not exceeding 200 nm. A low-thermal-budget MOCVD method for depositing a ferroelectric thin film having a thickness in a range of from 30 nm to 90 nm includes an RTP treatment before depositing the top electrode and an RTP treatment after depositing the top electrode and etching the ferroelectric layer.Type: ApplicationFiled: July 24, 2003Publication date: July 8, 2004Applicant: Symetrix CorporationInventors: Carlos A. Paz de Araujo, Larry D. McMillan, Narayan Solayappan, Vikram Joshi
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Patent number: 6743643Abstract: A nonconductive hydrogen barrier layer is deposited on a substrate and completely covers the surface area over a memory capacitor and a MOSFET switch of an integrated circuit memory cell. A portion of an insulator layer adjacent to the bottom electrode of a memory capacitor is removed by etching to form a moat region. A nonconductive oxygen barrier layer is deposited to cover the sidewall and bottom of the moat. The nonconductive oxygen barrier layer and a conductive diffusion barrier beneath the capacitor together provide a substantially continuous diffusion barrier between the capacitor and a switch. Also, the nonconductive hydrogen barrier layer, the nonconductive oxygen barrier, and the conductive diffusion barrier substantially completely envelop the capacitor, in particular a ferroelectric thin film in the capacitor.Type: GrantFiled: January 22, 2003Date of Patent: June 1, 2004Assignee: Symetrix CorporationInventors: Vikram Joshi, Narayan Solayappan, Carlos A. Paz de Araujo, Larry D. McMillan
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Publication number: 20040101977Abstract: A precursor for forming a thin film of layered superlattice material is applied to an integrated circuit substrate. The precursor coating is heated using rapid thermal processing (RTP) with a ramping rate of 100° C./second at a hold temperature in a range of from 500° C. to 900° C. for a cumulative heating time not exceeding 30 minutes, and preferably less than 5 minutes. In fabricating a ferroelectric memory cell, the coating is heated in oxygen using RTP, then a top electrode layer is formed, and then the substrate including the coating is heated using RTP in oxygen or in nonreactive gas after forming the top electrode layer. The thin film of layered superlattice material preferably comprises strontium bismuth tantalate or strontium bismuth tantalum niobate, and preferably has a thickness in a range of from 25 nm to 120 nm. The process of fabricating a thin film of layered superlattice material typically has a thermal budget value not exceeding 960,000° C.Type: ApplicationFiled: November 22, 2002Publication date: May 27, 2004Applicant: Symetrix CorporationInventors: Jolanta Celinska, Vikram Joshi, Narayan Solayappan, Myoungho Lim, Larry D. McMillan, Carlos A. Paz de Araujo
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Publication number: 20040089920Abstract: A nonconductive hydrogen barrier layer completely covers the surface area over a memory capacitor and a MOSFET switch of an integrated circuit memory cell. The nonconductive hydrogen barrier layer and a conductive diffusion barrier beneath the capacitor together provide a continuous diffusion barrier between the capacitor and a switch. Also, the nonconductive hydrogen barrier layer and the conductive diffusion barrier continuously envelop the capacitor, in particular a ferroelectric thin film in the capacitor. Preferably, a nonconductive “buried” diffusion barrier layer is disposed over an extended area, providing a continuous diffusion barrier between the capacitor and the switch. A preferred fabrication method comprises forming a thin stack-electrode layer on a capacitor dielectric layer, and then etching the substrate to form self-aligning capacitor stacks.Type: ApplicationFiled: October 28, 2003Publication date: May 13, 2004Applicant: Symetrix CorporationInventors: Vikram Joshi, Narayan Solayappan, Carlos A. Paz de Araujo, Larry D. McMillan
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Publication number: 20040051129Abstract: Integrated circuit capacitors in which the capacitor dielectric is a thin film of BST having a grain size smaller than 200 nanometers formed above a silicon germanium substrate. Typical grain sizes are 40 nm and less. The BST is formed by deposition of a liquid precursor by a spin-on process. The original liquid precursor includes an alkoxycarboxylate dissolved in 2-methoxyethanol and a xylene exchange is performed just prior to spinning. The precursor is dried in air at a temperature of about 400° C. and then furnace annealed in oxygen at a temperature of between 600° C. and 850° C.Type: ApplicationFiled: August 28, 2003Publication date: March 18, 2004Applicants: Symetrix Corporation, Matsushita Electric Industrial Co., Ltd.Inventors: Carlos A. Paz de Araujo, Masamichi Azuma, Larry D. McMillan, Koji Arita