Patents by Inventor Freidoon Mehrad
Freidoon Mehrad 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: 7585738Abstract: A method of forming a fully silicided semiconductor device with independent gate and source/drain doping and related device. At least some of the illustrative embodiments are methods comprising forming a gate stack over a substrate (the gate stack comprising a polysilicon layer and a blocking layer), and performing an ion implantation into an active region of the substrate adjacent to the gate stack (the blocking layer substantially blocks the ion implantation from the polysilicon layer).Type: GrantFiled: April 27, 2007Date of Patent: September 8, 2009Assignee: Texas Instruments IncorporatedInventors: Shaofeng Yu, Freidoon Mehrad, Jiong-Ping Lu
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Publication number: 20090191675Abstract: A method for making CMOS transistors that includes forming a NMOS transistor and a PMOS transistor having an undoped polysilicon gate electrode and a hardmask. The method also includes forming a layer of insulating material and then removing the hardmasks and a portion of the layer of insulating material. A layer of silicidation metal is formed and a first silicide anneal changes the undoped polysilicon gate electrodes into partially silicided gate electrodes. Dopants of a first type and a second type are implanted into the partially silicided gate electrode of the PMOS and NMOS transistors and a second silicide anneal is performed to change the doped partially silicided gate electrodes into fully silicided gate electrodes.Type: ApplicationFiled: January 30, 2008Publication date: July 30, 2009Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Freidoon Mehrad, Frank S. Johnson
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Publication number: 20090166629Abstract: A method of forming an integrated circuit having an NMOS transistor and a PMOS transistor is disclosed. The method includes performing pre-gate processing in a NMOS region and a PMOS region over and/or in a semiconductor body, and depositing a polysilicon layer over the semiconductor body in both the NMOS and PMOS regions. The method further includes performing a first type implant into the polysilicon layer in one of the NMOS region and PMOS region, and performing an amorphizing implant into the polysilicon layer in both the NMOS and PMOS regions, thereby converting the polysilicon layer into an amorphous silicon layer. The method further includes patterning the amorphous silicon layer to form gate electrodes, wherein a gate electrode resides in both the NMOS and PMOS regions.Type: ApplicationFiled: September 30, 2008Publication date: July 2, 2009Applicant: Texas Instruments IncorporatedInventors: Freidoon Mehrad, Jinhan Choi, Frank Scott Johnson
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Patent number: 7504339Abstract: A trench structure in a wafer of semiconductor material and the method of forming the trench structure are described. The trench structure is formed on a semiconductor wafer that has a top surface of slow oxidization rate—slower than that of other major crystallographic planes of the semiconductor material. The trench is etched into the semiconductor wafer. The trench has substantially vertical trench-sidewalls near the top surface, the vertical trench-sidewalls near the top surface containing crystallographic plane that oxidizes at a rate comparable to that of the top surface. An insulating layer is grown on the top surface and on the trench-sidewalls and on corners where sidewall surfaces approach the top surface, the insulating layer at the corners being substantially thicker than at the sidewall adjacent to the corners. The difference in the oxide thickness is due to the faster oxidizing planes exposed at the corners. Finally, the trench is filled with a dielectric material.Type: GrantFiled: June 1, 2005Date of Patent: March 17, 2009Assignee: Texas Instruments IncorporatedInventors: Zhihao Chen, Freidoon Mehrad, Brian K. Kirkpatrick, Jeff A. White, Edmund G. Russell, Jon Holt, Jason D. Mehigan
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Publication number: 20090057776Abstract: A method of forming fully silicided NMOS and PMOS semiconductor devices having independent polysilicon gate thicknesses, and related device. At least some of the illustrative embodiments are methods comprising forming an N-type gate over a semiconductor substrate (the N-type gate having a first thickness), forming a P-type gate over the semiconductor substrate (the P-type gate having a second thickness different than the first thickness), and performing a simultaneous silicidation of the N-type gate and the P-type gate.Type: ApplicationFiled: April 27, 2007Publication date: March 5, 2009Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Freidoon Mehrad, Shaofeng Yu, Steven A. Vitale, Craig H. Huffman
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Publication number: 20090050976Abstract: An improved method of forming a fully silicided (FUSI) gate in both NMOS and PMOS transistors of the same MOS device is disclosed. In one example, the method comprises forming a first silicide in at least a top portion of a gate electrode of the PMOS devices and not over the NMOS devices. The method further comprises concurrently forming a second silicide in at least a top portion of a gate electrode of both the NMOS and PMOS devices, and forming a FUSI gate silicide of the gate electrodes. In one embodiment, the thickness of the second silicide is greater than the first silicide by an amount which compensates for a difference in the rates of silicide formation between the NMOS and PMOS devices.Type: ApplicationFiled: August 24, 2007Publication date: February 26, 2009Inventors: Freidoon Mehrad, Frank S. Johnson
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Patent number: 7448395Abstract: The present invention substantially removes dry etch residue from a dry plasma etch process 110 prior to depositing a cobalt layer 124 on silicon substrate and/or polysilicon material. Subsequently, one or more annealing processes 128 are performed that cause the cobalt to react with the silicon thereby forming cobalt silicide regions. The lack of dry etch residue remaining between the deposited cobalt and the underlying silicon permits the cobalt silicide regions to be formed substantially uniform with a desired silicide sheet and contact resistance. The dry etch residue is substantially removed by performing a first cleaning operation 112 and then an extended cleaning operation 114 that includes a suitable cleaning solution. The first cleaning operation typically removes some, but not all of the dry etch residue. The extended cleaning operation 114 is performed at a higher temperature and/or for an extended duration and substantially removes dry etch residue remaining after the first cleaning operation 112.Type: GrantFiled: July 19, 2004Date of Patent: November 11, 2008Assignee: Texas Instruments IncorporatedInventors: Jiong-Ping Lu, Freidoon Mehrad, Lindsey Hall, Vivian Liu, Clint Montgomery, Scott Johnson
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Publication number: 20080265344Abstract: A method of simultaneously siliciding a polysilicon gate and source/drain of a semiconductor device, and related device. At least some of the illustrative embodiments are methods comprising forming a gate stack over a semiconductor substrate (the gate stack comprising a first polysilicon layer, a first nitride layer, and a second polysilicon layer), forming a second nitride layer over an active region in the semiconductor substrate adjacent to the gate stack, performing a chemical mechanical polishing that stops on the first nitride layer and on the second nitride layer, removing the first nitride layer and the second nitride layer, and performing a simultaneous silicidation of the first polysilicon layer and the active region.Type: ApplicationFiled: April 27, 2007Publication date: October 30, 2008Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Freidoon Mehrad, Shaofeng Yu, Steven A. Vitale, Joe G. Tran
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Publication number: 20080265420Abstract: A method of forming a fully silicided semiconductor device with independent gate and source/drain doping and related device. At least some of the illustrative embodiments are methods comprising forming a gate stack over a substrate (the gate stack comprising a polysilicon layer and a blocking layer), and performing an ion implantation into an active region of the substrate adjacent to the gate stack (the blocking layer substantially blocks the ion implantation from the polysilicon layer).Type: ApplicationFiled: April 27, 2007Publication date: October 30, 2008Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Shaofeng Yu, Freidoon Mehrad, Jiong-Ping Lu
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Publication number: 20080268631Abstract: A method for fabricating a semiconductor device includes forming a silicided gate utilizing a CMP stack. The CMP stack includes a first liner formed over the underlying semiconductor device and a first dielectric layer formed over the first liner layer. The first dielectric layer is formed to approximately the height of the gate. A second liner layer is formed over the first dielectric layer. Since the first dielectric layer is formed to approximately the height of the gate, the second liner over the moat regions is at approximately the height of the first liner over the gate. A CMP process is performed to expose the first liner over the top of the gate. Since the first dielectric layer is formed to the height of the gate, a portion of the second liner remains over the moat regions after the CMP process. Afterwards, the gate is exposed and a silicidation is performed to create a silicided gate.Type: ApplicationFiled: April 27, 2007Publication date: October 30, 2008Inventors: Frank Scott Johnson, Freidoon Mehrad
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Publication number: 20080265345Abstract: A method of forming a fully silicided semiconductor device with independent gate and source/drain doping and related device. At least some of the illustrative embodiments are methods comprising forming a gate stack over a substrate (the gate stack comprising a polysilicon layer and a blocking layer), and performing an ion implantation into an active region of the substrate adjacent to the gate stack (the blocking layer substantially blocks the ion implantation from the polysilicon layer).Type: ApplicationFiled: June 9, 2008Publication date: October 30, 2008Applicant: Texas Instruments IncorporatedInventors: Shaofeng Yu, Freidoon Mehrad, Jiong-Ping Lu
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Publication number: 20080233747Abstract: In one aspect, there us provided a method of manufacturing a semiconductor device that comprises placing an oxide layer over a gate electrode and sidewall spacers located adjacent thereto, placing a protective layer over the oxide layer, conducting a plasma etch to remove portions of the protective layer and the first oxide layer that are located over the gate electrode and expose a surface of the gate electrode, wherein the plasma etch is selective to polysilicon. A soft etch is conducted subsequent to the plasma etch. The soft etch includes an inorganic-based fluorine containing gas and an inert gas, wherein the plasma etch leaves a film on the gate electrode that inhibits silicidation of the gate electrode and wherein the soft etch removes the film. The gate electrode is silicided with a metal subsequent to conducting the soft etch.Type: ApplicationFiled: March 23, 2007Publication date: September 25, 2008Applicant: Texas Instruments IncorporatedInventors: Jinhan Choi, Freidoon Mehrad, Frank S. Johnson
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Publication number: 20080230846Abstract: A method of manufacturing a semiconductor device, comprising forming a metal silicide gate electrode on a semiconductor substrate surface. The method also comprises exposing the metal silicide gate electrode and the substrate surface to a cleaning process. The cleaning process includes a dry plasma etch using an anhydrous fluoride-containing feed gas and a thermal sublimation configured to leave the metal silicide gate electrode substantially unaltered. The method also comprises depositing a metal layer on source and drain regions of the substrate surface and annealing the metal layer and the source and drain regions of the substrate surface to form metal silicide source and drain contacts.Type: ApplicationFiled: March 23, 2007Publication date: September 25, 2008Applicant: Texas Instruments IncorporatedInventors: Yaw S. Obeng, Juanita DeLoach, Freidoon Mehrad
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Publication number: 20080206973Abstract: An improved method of forming a fully silicided (FUSI) gate in both NMOS and PMOS transistors of the same MOS device is disclosed. In one example, the method comprises forming oxide and nitride etch-stop layers over a top portion of the gates of the NMOS and PMOS transistors, forming a blocking layer over the etch-stop layer, planarizing the blocking layer down to the etch-stop layer over the gates, and removing a portion of the etch-stop layer overlying the gates. The method further includes implanting a preamorphizing species into the exposed gates to amorphize the gates, thereby permitting uniform silicide formation thereafter at substantially the same rates in the NMOS and PMOS transistors. The method may further comprise removing any remaining oxide or blocking layers, forming the gate silicide over the gates to form the FUSI gates, and forming source/drain silicide in moat areas of the NMOS and PMOS transistors.Type: ApplicationFiled: February 26, 2007Publication date: August 28, 2008Inventors: Frank Scott Johnson, Freidoon Mehrad, Jiong-Ping Lu
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Publication number: 20080176345Abstract: Gate dielectric punch through and/or incomplete silicidation or metallization events that may occur during transistor formation are identified. The events are identified just after gate electrodes are formed in order to characterize the degree of faulty transistors for process control purposes and to scrap product if sufficiently defective so that subsequent resources are not unnecessarily expended. An electron beam or ebeam is directed at locations of a workpiece whereon on or more transistors are formed. Electrons that are resultantly emitted from these locations are detected and used to develop respective gray level values (GLV's). Gate dielectric punch through and/or incomplete silicidation or metallization events are identified by finding high or low GLV's relative to neighboring areas.Type: ApplicationFiled: January 19, 2007Publication date: July 24, 2008Inventors: Shaofeng Yu, Richard L. Guldi, Jiong-Ping Lu, Freidoon Mehrad, Jae Hyun Park
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Patent number: 7396716Abstract: The present invention provides a method of fabricating a microelectronics device. In one aspect, the method comprises forming a capping layer 610 over gate structures 230 located over a microelectronics substrate 210 wherein the gate structures 230 include sidewall spacers 515 and have a doped region 525 located between them. A protective layer 710 is placed over the capping layer 610 and the doped region 525, and a portion of the protective layer 710 and capping layer 610 that are located over the gate structures are removed to expose a top surface of the gate structures 230. A remaining portion of the protective layer 710 and capping layer 610 remains over the doped region 525. With the top surface of the gate structures 230 exposed, metal is incorporated into the gate structures to form gate electrodes 230.Type: GrantFiled: August 11, 2005Date of Patent: July 8, 2008Assignee: Texas Instruments IncorporatedInventors: Freidoon Mehrad, Shaofeng Yu, Joe G. Tran
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Patent number: 7244642Abstract: The present invention provides a method of fabricating a microelectronics device. In one aspect, the method comprises depositing a protective layer (510) over a spacer material (415) located over gate electrodes (250) and a doped region (255) located between the gate electrodes (250), removing a portion of the spacer material (415) and the protective layer (510) located over the gate electrodes (250). A remaining portion of the spacer material (415) remains over the top surface of the gate electrodes (250) and over the doped region (255), and a portion of the protective layer (510) remains over the doped region (255). The method further comprises removing the remaining portion of the spacer material (415) to form spacer sidewalls on the gate electrodes (250), expose the top surface of the gate electrodes (250), and leave a remnant of the spacer material (415) over the doped region (255).Type: GrantFiled: September 16, 2005Date of Patent: July 17, 2007Assignee: Texas Instruments IncorporatedInventors: Steven A. Vitale, Hyesook Hong, Freidoon Mehrad
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Publication number: 20070066007Abstract: The present invention provides a method of fabricating a microelectronics device. In one aspect, the method comprises depositing a protective layer (510) over a spacer material (415) located over gate electrodes (250) and a doped region (255) located between the gate electrodes (250), removing a portion of the spacer material (415) and the protective layer (510) located over the gate electrodes (250). A remaining portion of the spacer material (415) remains over the top surface of the gate electrodes (250) and over the doped region (255), and a portion of the protective layer (510) remains over the doped region (255). The method further comprises removing the remaining portion of the spacer material (415) to form spacer sidewalls on the gate electrodes (250), expose the top surface of the gate electrodes (250), and leave a remnant of the spacer material (415) over the doped region (255).Type: ApplicationFiled: September 16, 2005Publication date: March 22, 2007Applicant: Texas Instruments Inc.Inventors: Steven Vitale, Hyesook Hong, Freidoon Mehrad
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Publication number: 20070037342Abstract: The present invention provides a method of fabricating a microelectronics device. In one aspect, the method comprises forming a capping layer 610 over gate structures 230 located over a microelectronics substrate 210 wherein the gate structures 230 include sidewall spacers 515 and have a doped region 525 located between them. A protective layer 710 is placed over the capping layer 610 and the doped region 525, and a portion of the protective layer 710 and capping layer 610 that are located over the gate structures are removed to expose a top surface of the gate structures 230. A remaining portion of the protective layer 710 and capping layer 610 remains over the doped region 525. With the top surface of the gate structures 230 exposed, metal is incorporated into the gate structures to form gate electrodes 230.Type: ApplicationFiled: August 11, 2005Publication date: February 15, 2007Applicant: Texas Instruments, IncorporatedInventors: Freidoon Mehrad, Shaofeng Yu, Joe Tran
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Patent number: 7112497Abstract: The present invention pertains to a multi-layer sidewall process (100) that facilitates forming a transistor in a manner that allows adherence to certain design rules while concurrently mitigating adverse effects associated with forming areas of transistors close to one another. First sidewall spacers having first widths are formed (124) alongside a gate structure of a transistor to facilitate implanting source/drain dopants far enough away from the gate structure so that dopant atoms are unlikely to migrate into a channel area under the gate structure. Additionally, the process provides uniform layers for dopant atoms to pass through to mitigate variations in device characteristics across a wafer. The manner of forming the sidewall spacers also allows a salicide blocking process to be simplified. The first sidewall spacers are subsequently reduced (132) to establish second sidewall spacers having second widths which are smaller than the first widths.Type: GrantFiled: June 25, 2004Date of Patent: September 26, 2006Assignee: Texas Instruments IncorporatedInventors: Freidoon Mehrad, Vivian Liu, Amitava Chatterjee