Patents by Inventor Pragati Kumar
Pragati Kumar 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: 8975147Abstract: This disclosure provides a method of fabricating a semiconductor stack and associated device, such as a capacitor and DRAM cell. In particular, a bottom electrode has a material selected for lattice matching characteristics. This material may be created from a relatively inexpensive metal oxide which is processed to adopt a conductive, but difficult-to-produce oxide state, with specific crystalline form; to provide one example, specific materials are disclosed that are compatible with the growth of rutile phase titanium dioxide (TiO2) for use as a dielectric, thereby leading to predictable and reproducible higher dielectric constant and lower effective oxide thickness and, thus, greater part density at lower cost.Type: GrantFiled: December 7, 2012Date of Patent: March 10, 2015Assignees: Intermolecular, Inc., Elpida Memory, Inc.Inventors: Xiangxin Rui, Hanhong Chen, Pragati Kumar, Sandra G. Malhotra
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Publication number: 20150056748Abstract: Resistive switching nonvolatile memory elements are provided. A metal-containing layer and an oxide layer for a memory element can be heated using rapid thermal annealing techniques. During heating, the oxide layer may decompose and react with the metal-containing layer. Oxygen from the decomposing oxide layer may form a metal oxide with metal from the metal-containing layer. The resulting metal oxide may exhibit resistive switching for the resistive switching memory elements.Type: ApplicationFiled: October 2, 2014Publication date: February 26, 2015Inventors: Pragati Kumar, Sean Barstow, Tony P. Chiang, Sunil Shanker
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Patent number: 8963117Abstract: This disclosure provides a nonvolatile memory device and related methods of manufacture and operation. The device may include one or more resistive random access memory (ReRAM) approaches to provide a memory device with more predictable operation. In particular, the forming voltage required by particular designs may be reduced through the use of a barrier layer, a reverse polarity forming voltage pulse, a forming voltage pulse where electrons are injected from a lower work function electrode, or an anneal in a reducing environment. One or more of these techniques may be applied, depending on the desired application and results.Type: GrantFiled: September 5, 2013Date of Patent: February 24, 2015Assignee: Intermolecular, Inc.Inventors: Pragati Kumar, Tony P. Chiang, Prashant B Phatak, Yun Wang
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Publication number: 20150034896Abstract: Nonvolatile memory elements including resistive switching metal oxides may be formed in one or more layers on an integrated circuit. Each memory element may have a first conductive layer, a metal oxide layer, and a second conductive layer. Electrical devices such as diodes may be coupled in series with the memory elements. The first conductive layer may be formed from a metal nitride. The metal oxide layer may contain the same metal as the first conductive layer. The metal oxide may form an ohmic contact or a Schottky contact with the first conductive layer. The second conductive layer may form an ohmic contact or Schottky contact with the metal oxide layer. The first conductive layer, the metal oxide layer, and the second conductive layer may include sublayers. The second conductive layer may include an adhesion or barrier layer and a workfunction control layer.Type: ApplicationFiled: September 17, 2014Publication date: February 5, 2015Inventors: Pragati Kumar, Sean Barstow, Tony P. Chiang, Sandra G Malhotra
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Patent number: 8921156Abstract: Non-volatile resistive-switching memories are described, including a memory element having a first electrode, a second electrode, a metal oxide between the first electrode and the second electrode. The metal oxide switches using bulk-mediated switching, has a bandgap greater than 4 electron volts (eV), has a set voltage for a set operation of at least one volt per one hundred angstroms of a thickness of the metal oxide, and has a leakage current density less than 40 amps per square centimeter (A/cm2) measured at 0.5 volts (V) per twenty angstroms of the thickness of the metal oxide.Type: GrantFiled: October 4, 2013Date of Patent: December 30, 2014Assignee: Intermolecular, Inc.Inventors: Prashant B Phatak, Tony P. Chiang, Pragati Kumar, Michael Miller
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Publication number: 20140361236Abstract: ALD processing techniques for forming non-volatile resistive-switching memories are described. In one embodiment, a method includes forming a first electrode on a substrate, maintaining a pedestal temperature for an atomic layer deposition (ALD) process of less than 100° Celsius, forming at least one metal oxide layer over the first electrode, wherein the forming the at least one metal oxide layer is performed using the ALD process using a purge duration of less than 20 seconds, and forming a second electrode over the at least one metal oxide layer.Type: ApplicationFiled: August 25, 2014Publication date: December 11, 2014Inventors: Nobumichi Fuchigami, Pragati Kumar, Prashant B. Phatak
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Patent number: 8900422Abstract: This disclosure provides (a) methods of making an oxide layer (e.g., a dielectric layer) based on yttrium and titanium, to have a high dielectric constant and low leakage characteristic and (b) related devices and structures. An oxide layer having both yttrium and titanium may be fabricated either as an amorphous oxide or as an alternating series of monolayers. In several embodiments, the oxide is characterized by a yttrium contribution to total metal that is specifically controlled. The oxide layer can be produced as the result of a reactive process, if desired, via either a PVD process or, alternatively, via an atomic layer deposition process that employs specific precursor materials to allow for a common process temperature window for both titanium and yttrium reactions.Type: GrantFiled: April 17, 2009Date of Patent: December 2, 2014Assignees: Intermolecular, Inc., Elpida Memory, Inc.Inventors: Imran Hashim, Indranil De, Tony Chiang, Edward Haywood, Hanhong Chen, Nobi Fuchigami, Pragati Kumar, Sandra Malhotra, Sunil Shanker
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Patent number: 8900418Abstract: This disclosure provides (a) methods of making an oxide layer (e.g., a dielectric layer) based on yttrium and titanium, to have a high dielectric constant and low leakage characteristic and (b) related devices and structures. An oxide layer having both yttrium and titanium may be fabricated either as an amorphous oxide or as an alternating series of monolayers. In several embodiments, the oxide is characterized by a yttrium contribution to total metal that is specifically controlled. The oxide layer can be produced as the result of a reactive process, if desired, via either a PVD process or, alternatively, via an atomic layer deposition process that employs specific precursor materials to allow for a common process temperature window for both titanium and yttrium reactions.Type: GrantFiled: November 14, 2012Date of Patent: December 2, 2014Assignees: Intermolecular, Inc., Elpida Memory, Inc.Inventors: Imran Hashim, Hanhong Chen, Tony Chiang, Indranil De, Nobi Fuchigami, Edward Haywood, Pragati Kumar, Sandra Malhotra, Sunil Shanker
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Patent number: 8901708Abstract: This disclosure provides (a) methods of making an oxide layer (e.g., a dielectric layer) based on yttrium and titanium, to have a high dielectric constant and low leakage characteristic and (b) related devices and structures. An oxide layer having both yttrium and titanium may be fabricated either as an amorphous oxide or as an alternating series of monolayers. In several embodiments, the oxide is characterized by a yttrium contribution to total metal that is specifically controlled. The oxide layer can be produced as the result of a reactive process, if desired, via either a PVD process or, alternatively, via an atomic layer deposition process that employs specific precursor materials to allow for a common process temperature window for both titanium and yttrium reactions.Type: GrantFiled: November 13, 2012Date of Patent: December 2, 2014Assignee: Intermolecular, Inc.Inventors: Imran Hashim, Hanhong Chen, Tony Chiang, Indranil De, Nobumichi Fuchigami, Edward Haywood, Pragati Kumar, Sandra Malhotra, Sunil Shanker
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Patent number: 8895951Abstract: This disclosure provides a method of fabricating a semiconductor device layer and an associated memory cell. Empirical data may be used to generate a hysteresis curve associated with deposition for a metal-insulator-metal structure, with curve measurements reflecting variance of an electrical property as a function of cathode voltage used during a sputtering process. By generating at least one voltage level to be used during the sputtering process, where the voltage reflects a suitable value for the electrical property from among the values obtainable in mixed-mode deposition, a semiconductor device layer may be produced with improved characteristics and durability. A multistable memory cell or array of such cells manufactured according to this process can, for a set of given materials, be fabricated to have minimal leakage or “off” current characteristics (Ileak or Ioff, respectively) or a maximum ratio of “on” current to “off” current (Ion/Ioff).Type: GrantFiled: September 30, 2011Date of Patent: November 25, 2014Assignee: Intermolecular, Inc.Inventors: Wayne R French, Tony P. Chiang, Pragati Kumar, Prashant B Phatak
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Patent number: 8877550Abstract: Resistive switching nonvolatile memory elements are provided. A metal-containing layer and an oxide layer for a memory element can be heated using rapid thermal annealing techniques. During heating, the oxide layer may decompose and react with the metal-containing layer. Oxygen from the decomposing oxide layer may form a metal oxide with metal from the metal-containing layer. The resulting metal oxide may exhibit resistive switching for the resistive switching memory elements.Type: GrantFiled: February 10, 2012Date of Patent: November 4, 2014Assignee: Intermolecular, Inc.Inventors: Pragati Kumar, Sean Barstow, Sunil Shanker, Tony Chiang
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Patent number: 8873276Abstract: Nonvolatile memory elements including resistive switching metal oxides may be formed in one or more layers on an integrated circuit. Each memory element may have a first conductive layer, a metal oxide layer, and a second conductive layer. Electrical devices such as diodes may be coupled in series with the memory elements. The first conductive layer may be formed from a metal nitride. The metal oxide layer may contain the same metal as the first conductive layer. The metal oxide may form an ohmic contact or a Schottky contact with the first conductive layer. The second conductive layer may form an ohmic contact or Schottky contact with the metal oxide layer. The first conductive layer, the metal oxide layer, and the second conductive layer may include sublayers. The second conductive layer may include an adhesion or barrier layer and a workfunction control layer.Type: GrantFiled: October 21, 2013Date of Patent: October 28, 2014Assignee: Intermolecular, Inc.Inventors: Pragati Kumar, Sean Barstow, Tony P. Chiang, Sandra G Malhotra
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Patent number: 8859301Abstract: Determining an unknown step coverage of a thin film deposited on a 3D wafer includes exposing a planar wafer comprising a first film deposited thereon to X-ray radiation to create first fluorescent radiation; detecting the first fluorescent radiation; measuring a number of XRF counts on the planar wafer; creating an XRF model of the planar wafer; providing a portion of the 3D wafer comprising troughs and a second film deposited thereon; determining a multiplier factor between the portion of the 3D wafer and the planar wafer; exposing the portion of the 3D wafer to X-ray radiation to create second fluorescent radiation; detecting the second fluorescent radiation; measuring a number of XRF counts on the portion of the 3D wafer; calculating a step coverage of the portion of the 3D wafer; and determining a uniformity of the 3D wafer based on the step coverage of the portion of the 3D wafer.Type: GrantFiled: June 11, 2013Date of Patent: October 14, 2014Assignee: Intermolecular, Inc.Inventors: Hanhong Chen, Edward Haywood, Pragati Kumar
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Patent number: 8847190Abstract: ALD processing techniques for forming non-volatile resistive-switching memories are described. In one embodiment, a method includes forming a first electrode on a substrate, maintaining a pedestal temperature for an atomic layer deposition (ALD) process of less than 100° Celsius, forming at least one metal oxide layer over the first electrode, wherein the forming the at least one metal oxide layer is performed using the ALD process using a purge duration of less than 20 seconds, and forming a second electrode over the at least one metal oxide layer.Type: GrantFiled: November 27, 2013Date of Patent: September 30, 2014Assignee: Intermolecular, Inc.Inventors: Nobumichi Fuchigami, Pragati Kumar, Prashant B Phatak
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Publication number: 20140256111Abstract: Nonvolatile memory elements that are based on resistive switching memory element layers are provided. A nonvolatile memory element may have a resistive switching metal oxide layer. The resistive switching metal oxide layer may have one or more layers of oxide. A resistive switching metal oxide may be doped with a dopant that increases its melting temperature and enhances its thermal stability. Layers may be formed to enhance the thermal stability of the nonvolatile memory element. An electrode for a nonvolatile memory element may contain a conductive layer and a buffer layer.Type: ApplicationFiled: May 19, 2014Publication date: September 11, 2014Applicant: Intermolecular Inc.Inventors: Sandra G. Malhotra, Sean Barstow, Tony P. Chiang, Wayne R. French, Pragati Kumar, Prashant B. Phatak, Sunil Shanker, Wen Wu
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Patent number: 8828821Abstract: This disclosure provides a method of fabricating a semiconductor stack and associated device such as a capacitor and DRAM cell. In particular, a bottom electrode upon which a dielectric layer is to be grown may have a ruthenium-based surface. Lattice matching of the ruthenium surface with the dielectric layer (e.g., titanium oxide, strontium titanate or barium strontium titanate) helps promote the growth of rutile-phase titanium oxide, thereby leading to higher dielectric constant and lower effective oxide thickness. The ruthenium-based material also provides a high work function material, leading to lower leakage. To mitigate nucleation delay associated with the use of ruthenium, an adherence or glue layer based in titanium may be employed. A pretreatment process may be further employed so as to increase effective capacitor plate area, and thus promote even further improvements in dielectric constant and effective oxide thickness (“EOT”).Type: GrantFiled: September 18, 2009Date of Patent: September 9, 2014Assignees: Intermolecular, Inc., Elpida Memory, Inc.Inventors: Hanhong Chen, Nobumichi Fuchigami, Imran Hashim, Pragati Kumar, Sandra Malhotra, Sunil Shanker
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Patent number: 8809160Abstract: This disclosure provides a method of fabricating a semiconductor stack and associated device, such as a capacitor or DRAM cell. In such a device, a high-K zirconia-based layer may be used as the primary dielectric together with a relatively inexpensive metal electrode based on titanium nitride. To prevent corruption of the electrode during device formation, a thin barrier layer can be used seal the electrode prior to the use of a high temperature process and a (high-concentration or dosage) ozone reagent (i.e., to create a high-K zirconia-based layer). In some embodiments, the barrier layer can also be zirconia-based, for example, a thin layer of doped or un-doped amorphous zirconia. Fabrication of a device in this manner facilitates formation of a device with dielectric constant of greater than 40 based on zirconia and titanium nitride, and generally helps produce less costly, increasingly dense DRAM cells and other semiconductor structures.Type: GrantFiled: December 22, 2011Date of Patent: August 19, 2014Assignees: Intermolecular, Inc., Elpida Memory, Inc.Inventors: Hanhong Chen, Edward Haywood, Pragati Kumar, Sandra G Malhotra, Xiangxin Rui
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Patent number: 8765567Abstract: Nonvolatile memory elements that are based on resistive switching memory element layers are provided. A nonvolatile memory element may have a resistive switching metal oxide layer. The resistive switching metal oxide layer may have one or more layers of oxide. A resistive switching metal oxide may be doped with a dopant that increases its melting temperature and enhances its thermal stability. Layers may be formed to enhance the thermal stability of the nonvolatile memory element. An electrode for a nonvolatile memory element may contain a conductive layer and a buffer layer.Type: GrantFiled: October 24, 2013Date of Patent: July 1, 2014Assignee: Intermolecular, Inc.Inventors: Sandra G Malhotra, Sean Barstow, Tony P. Chiang, Pragati Kumar, Prashant B Phatak, Sunil Shanker, Wen Wu
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Patent number: 8737036Abstract: This disclosure provides (a) methods of making an oxide layer (e.g., a dielectric layer) based on titanium oxide, to suppress the formation of anatase-phase titanium oxide and (b) related devices and structures. A metal-insulator-metal (“MIM”) stack is formed using an ozone pretreatment process of a bottom electrode (or other substrate) followed by an ALD process to form a TiO2 dielectric, rooted in the use of an amide-containing precursor. Following the ALD process, an oxidizing anneal process is applied in a manner is hot enough to heal defects in the TiO2 dielectric and reduce interface states between TiO2 and electrode; the anneal temperature is selected so as to not be so hot as to disrupt BEL surface roughness. Further process variants may include doping the titanium oxide, pedestal heating during the ALD process to 275-300 degrees Celsius, use of platinum or ruthenium for the BEL, and plural reagent pulses of ozone for each ALD process cycle.Type: GrantFiled: October 22, 2012Date of Patent: May 27, 2014Assignee: Intermolecular, Inc.Inventors: Hanhong Chen, Nobumichi Fuchigami, Imran Hashim, Edward L. Haywood, Pragati Kumar, Sandra G. Malhotra, Monica Sawkar Mathur, Prashant B. Phatak, Sunil Shanker
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Publication number: 20140084236Abstract: ALD processing techniques for forming non-volatile resistive-switching memories are described. In one embodiment, a method includes forming a first electrode on a substrate, maintaining a pedestal temperature for an atomic layer deposition (ALD) process of less than 100° Celsius, forming at least one metal oxide layer over the first electrode, wherein the forming the at least one metal oxide layer is performed using the ALD process using a purge duration of less than 20 seconds, and forming a second electrode over the at least one metal oxide layer.Type: ApplicationFiled: November 27, 2013Publication date: March 27, 2014Applicant: Intermolecular Inc.Inventors: Nobumichi Fuchigami, Pragati KUMAR, Prashant B. Phatak