Patents by Inventor David R. Evans
David R. Evans 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: 6939724Abstract: A method for obtaining reversible resistance switches on a PCMO thin film when integrated with a highly crystallized seed layer includes depositing, by MOCVD, a seed layer of PCMO, in highly crystalline form, thin film, having a thickness of between about 50 ? to 300 ?, depositing a second PCMO thin film layer on the seed layer, by spin coating, having a thickness of between about 500 ? to 3000 ?, to form a combined PCMO layer; increasing the resistance of the combined PCMO film in a semiconductor device by applying a negative electric pulse of between about ?4V to ?5V, having a pulse width of between about 75 nsec to 1 ?sec; and decreasing the resistance of the combined PCMO layer in a semiconductor device by applying a positive electric pulse of between about +2.5V to +4V, having a pulse width greater than 2.0 ?sec.Type: GrantFiled: August 13, 2003Date of Patent: September 6, 2005Assignee: Sharp Laboratories of America, Inc.Inventors: Wei-Wei Zhuang, Tingkai Li, David R. Evans, Sheng Teng Hsu, Wei Pan
-
Patent number: 6927074Abstract: An asymmetric memory cell and method for forming an asymmetric memory cell are provided. The method comprises: forming a bottom electrode having a first area; forming an electrical pulse various resistance (EPVR) material overlying the bottom electrode; forming a top electrode overlying the EPVR layer having a second area, less than the first area. In some aspects the second area is at least 20% smaller than the first area. The EPVR is a material such as colossal magnetoresistance (CMR), high temperature super conducting (HTSC), or perovskite metal oxide materials. The method further comprises: inducing an electric field between the electrodes; inducing current flow through the EPVR adjacent the top electrode; and, in response to inducing current flow through the EPVR adjacent the top electrode, modifying the resistance of the EPVR. Typically, the resistance is modified within the range of 100 ohms to 10 mega-ohms.Type: GrantFiled: May 21, 2003Date of Patent: August 9, 2005Assignee: Sharp Laboratories of America, Inc.Inventors: Sheng Teng Hsu, Tingkai Li, David R. Evans
-
Patent number: 6927120Abstract: Asymmetrically structured memory cells and a fabrication method are provided. The method comprises: forming a bottom electrode; forming an electrical pulse various resistance (EPVR) first layer having a polycrystalline structure over the bottom electrode; forming an EPVR second layer adjacent the first layer, with a nano-crystalline or amorphous structure; and, forming a top electrode overlying the first and second EPVR layers. EPVR materials include CMR, high temperature super conductor (HTSC), or perovskite metal oxide materials. In one aspect, the EPVR first layer is deposited with a metalorganic spin coat (MOD) process at a temperature in the range between 550 and 700 degrees C. The EPVR second layer is formed at a temperature less than, or equal to the deposition temperature of the first layer. After a step of removing solvents, the MOD deposited EPVR second layer is formed at a temperature less than, or equal to the 550 degrees C.Type: GrantFiled: May 21, 2003Date of Patent: August 9, 2005Assignee: Sharp Laboratories of America, Inc.Inventors: Sheng Teng Hsu, Tingkal Li, David R. Evans, Wei-Wei Zhuang, Wei Pan
-
Patent number: 6899858Abstract: A method of preparing a hafnium nitrate thin film includes placing phosphorus pentoxide in a first vessel; connecting the first vessel to a second vessel containing hafnium tetrachloride; cooling the second vessel with liquid nitrogen; dropping fuming nitric acid into the first vessel producing N2O5 gas; allowing the N2O5 gas to enter the second vessel; heating the first vessel until the reaction is substantially complete; disconnecting the two vessels; removing the second vessel from the liquid nitrogen bath; heating the second vessel; refluxing the contents of the second vessel; drying the compound in the second vessel by dynamic pumping; purifying the compound in the second vessel by sublimation to form Hf(NO3)4, and heating the Hf(NO3)4 to produce HfO2 for use in an ALCVD process.Type: GrantFiled: January 23, 2003Date of Patent: May 31, 2005Assignee: Sharp Laboratories of America, Inc.Inventors: Wei-Wei Zhuang, David R. Evans, Sheng Teng Hsu
-
Patent number: 6849467Abstract: A method of forming an H2 passivation layer in an FeRAM includes preparing a silicon substrate; depositing a layer of TiOx thin film, where 0<x<2, on a damascene structure; plasma space etching of the Ti or TiOx thin film to form a TiOx sidewall; annealing the TiOx side wall thin film form a TiO2 thin film; depositing a layer of ferroelectric material; and metallizing the structure to form a FeRAM.Type: GrantFiled: July 16, 2003Date of Patent: February 1, 2005Assignee: Sharp Laboratories of America, Inc.Inventors: Tingkai Li, Wei Pan, Robert A. Barrowcliff, David R. Evans, Sheng Teng Hsu
-
Publication number: 20040235247Abstract: Asymmetrically structured memory cells and a fabrication method are provided. The method comprises: forming a bottom electrode; forming an electrical pulse various resistance (EPVR) first layer having a polycrystalline structure over the bottom electrode; forming an EPVR second layer adjacent the first layer, with a nano-crystalline or amorphous structure; and, forming a top electrode overlying the first and second EPVR layers. EPVR materials include CMR, high temperature super conductor (HTSC), or perovskite metal oxide materials. In one aspect, the EPVR first layer is deposited with a metalorganic spin coat (MOD) process at a temperature in the range between 550 and 700 degrees C. The EPVR second layer is formed at a temperature less than, or equal to the deposition temperature of the first layer. After a step of removing solvents, the MOD deposited EPVR second layer is formed at a temperature less than, or equal to the 550 degrees C.Type: ApplicationFiled: May 21, 2003Publication date: November 25, 2004Applicant: Sharp Laboratories of America, Inc.Inventors: Sheng Teng Hsu, Tingkal Li, David R. Evans, Wei-Wei Zhuang, Wei Pan
-
Publication number: 20040233708Abstract: An asymmetric memory cell and method for forming an asymmetric memory cell are provided. The method comprises: forming a bottom electrode having a first area; forming an electrical pulse various resistance (EPVR) material overlying the bottom electrode; forming a top electrode overlying the EPVR layer having a second area, less than the first area. In some aspects the second area is at least 20% smaller than the first area. The EPVR is a material such as colossal magnetoresistance (CMR), high temperature super conducting (HTSC), or perovskite metal oxide materials. The method further comprises: inducing an electric field between the electrodes; inducing current flow through the EPVR adjacent the top electrode; and, in response to inducing current flow through the EPVR adjacent the top electrode, modifying the resistance of the EPVR. Typically, the resistance is modified within the range of 100 ohms to 10 mega-ohms.Type: ApplicationFiled: May 21, 2003Publication date: November 25, 2004Applicant: Sharp Laboratories of America, Inc.Inventors: Sheng Teng Hsu, Tingkai Li, David R. Evans
-
Publication number: 20040203234Abstract: A method of forming a tungsten nitride thin film in an integrated circuit includes preparing a silicon substrate on a silicon wafer and placing the silicon wafer in a heatable chuck in a CVD vacuum chamber; placing a known quantity of a tungsten source in a variable-temperature bubbler to provide a gaseous tungsten source; setting the variable-temperature bubbler to a predetermined temperature; passing a carrier gas through the variable-temperature bubbler and carrying the gaseous tungsten source with the carrier gas into the CVD vacuum chamber; introducing a nitrogen-containing reactant gas into the CVD vacuum chamber; reacting the gaseous tungsten source and the nitrogen-containing reactant gas above the surface of the silicon wafer in a deposition process to deposit a WxNy thin film on the surface of the silicon wafer; and completing the integrated circuit containing the WxNy thin film.Type: ApplicationFiled: April 9, 2003Publication date: October 14, 2004Applicant: Sharp Laboratories of America, Inc.Inventors: Wei Pan, Robert Barrowcliff, David R Evans, Sheng Teng Hsu
-
Publication number: 20040185669Abstract: A method of etching includes preparing a substrate; depositing a first etch stop layer; forming an iridium bottom electrode layer; depositing a SiN layer; depositing and patterning an aluminum hard mask; etching a non-patterned SiN layer with a SiN selective etchant, stopping at the level of the iridium bottom electrode layer; etching the first etch stop layer with a second selective etchant; depositing an oxide layer and CMP the oxide layer to the level of the remaining SiN layer; wet etching the SiN layer to form a trench; depositing a layer of ferroelectric material in the trench formed by removal of the SiN layer; depositing a layer of high-k oxide; and completing the device, including metallization.Type: ApplicationFiled: March 17, 2003Publication date: September 23, 2004Applicant: Sharp Laboratories of America, Inc.Inventors: Tingkai Li, Bruce D. Ulrich, David R. Evans, Sheng Teng Hsu
-
Patent number: 6794198Abstract: A method of forming a PGO thin film on a high-k dielectric includes preparing a silicon substrate, including forming a high-k gate oxide layer thereon; patterning the high-k gate oxide; annealing the substrate in a first annealing step; placing the substrate in a MOCVD chamber; depositing a PGO thin film by injecting a PGO precursor into the MOCVD chamber; and annealing the structure having a PGO thin film on a high-k gate oxide in a second annealing step.Type: GrantFiled: June 25, 2003Date of Patent: September 21, 2004Assignee: Sharp Laboratories of America, Inc.Inventors: Tingkai Li, Sheng Teng Hsu, David R. Evans, Bruce D. Ulrich
-
Publication number: 20040170761Abstract: A single solution MOCVD precursor is provided for depositing PCMO. An MOCVD process is provided for controlling the composition of PCMO by determining the deposition rate of each metal component within the precursor solution and determining the molar ratio of the metals based on the deposition rates of each within the temperature ranges for substrate temperature and vaporizer temperature, and the composition of PCMO to be deposited. The composition of the PCMO is further controlled by adjusting the substrate temperature, the vaporizer temperature or both.Type: ApplicationFiled: February 27, 2003Publication date: September 2, 2004Applicant: Sharp Laboratories of America, Inc.Inventors: Tingkai Li, Wei-Wei Zhuang, Lawrence J. Charneski, David R. Evans, Sheng Teng Hsu
-
Patent number: 6777327Abstract: A rapid thermal process (RTP) provides steps wherein silicon wafers that are pre-coated with barrier metal films by either in-situ or ex-situ CVD or physical vapor deposition (PVD) are pre-treated, prior to deposition of a Cu film thereon, in a temperature range of between 250 and 550 degrees Celsius in a non-reactive gas such as hydrogen gas (H2), argon (Ar), or helium (He), or in an ambient vacuum. The chamber pressure typically is between 0.1 mTorr and 20 Torr, and the RTP time typically is between 30 to 100 seconds. Performing this rapid thermal process before deposition of the Cu film results in a thin, shiny, densely nucleated, and adhesive Cu film deposited on a variety of barrier metal surfaces. The pre-treatment process eliminates variations in the deposited Cu film caused by Cu precursors and is insensitive to variation in precursor composition, volatility, and other precursor variables.Type: GrantFiled: March 28, 2001Date of Patent: August 17, 2004Assignee: Sharp Laboratories of America, Inc.Inventors: Wei Pan, Jer-Shen Maa, David R. Evans, Sheng Teng Hsu
-
Patent number: 6774054Abstract: A method of forming a PCMO thin film in a RRAM device includes preparing a substrate; depositing a metal barrier layer on the substrate; forming a bottom electrode on the barrier layer; spin-coating a layer of Pr1−xCaxMnO3 (PCMO) on the bottom electrode using a PCMO precursor; baking the PCMO thin film in one or more baking steps; annealing the PCMO thin film in a first annealing step after each spin-coating step; repeating the spin-coating step, the baking step and the first annealing step until the PCMO thin film has a desired thickness; annealing the PCMO thin film in a second annealing step, thereby producing a PCMO thin film having a crystalline structure of Pr1−xCaxMnO3, where 0.2<=X<=0.5; depositing a top electrode; patterning the top electrode; and completing the RRAM device.Type: GrantFiled: August 13, 2003Date of Patent: August 10, 2004Assignee: Sharp Laboratories of America, Inc.Inventors: Fengyan Zhang, Wei-Wei Zhuang, David R. Evans, Sheng Teng Hsu
-
Publication number: 20040152307Abstract: A method of adhering copper thin film to a substrate in an integrated circuit structure includes preparing a substrate, including forming active regions and trenches for interconnect structures; depositing a metal barrier layer on the substrate; depositing an ultra thin film layer of tungsten over the barrier metal layer; depositing a copper thin film on the tungsten ultra thin film layer; removing excess copper and tungsten to the level of the metal barrier layer; and completing the integrated circuit structure.Type: ApplicationFiled: January 21, 2004Publication date: August 5, 2004Applicant: Sharp Laboratories of America, Inc.Inventors: Wei Pan, David R. Evans, Sheng Teng Hsu
-
Publication number: 20040146448Abstract: A method of preparing a hafnium nitrate thin film includes placing phosphorus pentoxide in a first vessel; connecting the first vessel to a second vessel containing hafnium tetrachloride; cooling the second vessel with liquid nitrogen; dropping fuming nitric acid into the first vessel producing N2O5 gas; allowing the N2O5 gas to enter the second vessel; heating the first vessel until the reaction is substantially complete; disconnecting the two vessels; removing the second vessel from the liquid nitrogen bath; heating the second vessel; refluxing the contents of the second vessel; drying the compound in the second vessel by dynamic pumping; purifying the compound in the second vessel by sublimation to form Hf(NO3)4, and heating the Hf(NO3)4 to produce HfO2 for use in an ALCVD process.Type: ApplicationFiled: January 23, 2003Publication date: July 29, 2004Applicant: Sharp Laboratories of America, Inc.Inventors: Wei-Wei Zhuang, David R. Evans, Sheng Teng Hsu
-
Patent number: 6764537Abstract: A method for chemical vapor deposition of copper metal thin film on a substrate includes heating a substrate onto which the copper metal thin film is to be deposited in a chemical vapor deposition chamber; vaporizing a precursor containing the copper metal, wherein the precursor is a compound of (&agr;-methylstyrene)Cu(I)(hfac), where hfac is hexafluoroacetylacetonate, and (hfac)Cu(I)L, where L is an alkene; introducing the vaporized precursor into the chemical vapor deposition chamber adjacent the heated substrate; and condensing the vaporized precursor onto the substrate thereby depositing copper metal onto the substrate. A copper metal precursor for use in the chemical vapor deposition of a copper metal thin film is a compound of (&agr;-methylstyrene)Cu(I)(hfac), where hfac is hexafluoroacetylacetonate, and (hfac)Cu(I)L, where L is an alkene taken from the group of alkenes consisting of 1-pentene, 1-hexene and trimethylvinylsilane.Type: GrantFiled: June 2, 2003Date of Patent: July 20, 2004Assignee: Sharp Laboratories of America, Inc.Inventors: Wei-Wei Zhuang, Lawrence J. Charneski, David R. Evans, Sheng Teng Hsu
-
Publication number: 20040121596Abstract: An alternating source MOCVD process is provided for depositing tungsten nitride thin films for use as barrier layers for copper interconnects. Alternating the tungsten precursor produces fine crystal grain films, or possibly amorphous films. The nitrogen source may also be alternated to form WN/W alternating layer films, as tungsten is deposited during periods where the nitrogen source is removed.Type: ApplicationFiled: December 19, 2002Publication date: June 24, 2004Applicant: Sharp Laboratories of America, Inc.Inventors: Wei Pan, David R. Evans, Sheng Teng Hsu
-
Patent number: 6723643Abstract: A method of CMP thin films during fabrication of IC devices includes preparing a substrate, including building IC component structures on the substrate; depositing a bottom electrode on the substrate; depositing a first CMP layer having a first known CMP selectivity on the substrate; patterning the first CMP layer to form a pattern having a lower margin; forming indicator structures on the first CMP layer in the pattern; depositing a second CMP layer having a second known CMP selectivity relative to that of the first CMP layer, including depositing portions of the second CMP layer in the pattern of the first CMP layer; CMP the structure so that the indicator structures are removed and any portion of the first CMP layer and second CMP layer are removed to a level corresponding to the lower margin; and completing the IC structure.Type: GrantFiled: March 17, 2003Date of Patent: April 20, 2004Assignee: Sharp Laboratories of America, Inc.Inventors: Wei Pan, David R. Evans, Allen W. Burmaster
-
Patent number: 6716744Abstract: A method of adhering copper thin film to a substrate in an integrated circuit structure includes preparing a substrate, including forming active regions and trenches for interconnect structures; depositing a metal barrier layer on the substrate; depositing an ultra thin film layer of tungsten over the barrier metal layer; depositing a copper thin film on the tungsten ultra thin film layer; removing excess copper and tungsten to the level of the metal barrier layer; and completing the integrated circuit structure.Type: GrantFiled: May 6, 2002Date of Patent: April 6, 2004Assignee: Sharp Laboratories of America, Inc.Inventors: Wei Pan, David R. Evans, Sheng Teng Hsu
-
Patent number: 6716691Abstract: A method of fabricating a CMOS have self-aligned shallow trench isolation, includes preparing a silicon substrate; forming a gate stack; depositing a layer of first polysilicon; trenching the substrate by shallow trench isolation to form a trench; filling the trench with oxide; depositing a second layer of polysilicon wherein the top surface of the second polysilicon layer is above the top surface of the first polysilicon layer; depositing a sacrificial oxide layer having a thickness of at least 1.5× that of the first polysilicon layer; CMP the sacrificial oxide layer to the level of the upper surface of the second polysilicon layer; depositing a third layer of polysilicon; patterning and etching the gate stack; implanting ions to form a source region, a drain region and the polysilicon gate; and completing the CMOS structure.Type: GrantFiled: June 25, 2003Date of Patent: April 6, 2004Assignee: Sharp Laboratories of America, Inc.Inventors: David R. Evans, Sheng Teng Hsu, Bruce D. Ulrich, Douglas J. Tweet, Lisa H. Stecker