Patents by Inventor Ravi Rajagopalan

Ravi Rajagopalan 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: 6789355
    Abstract: A liner for use in a horticultural planter contains an integral water tray which is located between inner and outer fibrous layers of a liner. The water tray extends from a bottom surface of the liner to a peripheral top edge. The water tray is integral with the liner and located between outer and inner fibrous layers. The water tray extends also from the bottom surface to a peripheral edge which is spaced apart from the peripheral top edge of the liner. An overflow region is therefore formed between the peripheral top edge of the liner and the peripheral edge of the water tray.
    Type: Grant
    Filed: March 31, 2003
    Date of Patent: September 14, 2004
    Assignee: The Pride Group, Inc.
    Inventor: Ravi Rajagopalan
  • Publication number: 20040016178
    Abstract: A liner for use in a horticultural planter contains an integral water tray which is located between inner and outer fibrous layers of a liner. The water tray extends from a bottom surface of the liner to a peripheral top edge. The water tray is integral with the liner and located between outer and inner fibrous layers. The water tray extends also from the bottom surface to a peripheral edge which is spaced apart from the peripheral top edge of the liner. An overflow region is therefore formed between the peripheral top edge of the liner and the peripheral edge of the water tray.
    Type: Application
    Filed: March 31, 2003
    Publication date: January 29, 2004
    Inventor: Ravi Rajagopalan
  • Patent number: 6677254
    Abstract: The formation of a barrier layer over a high k dielectric layer and deposition of a conducting layer over the barrier layer prevents intermigration between the species of the high k dielectric layer and the conducting layer and prevents oxygen scavenging of the high k dielectric layer. One example of a capacitor stack device provided includes a high k dielectric layer of Ta2O5, a barrier layer of TaON or TiON formed at least in part by a remote plasma process, and a top electrode of TiN. The processes may be conducted at about 300 to 700° C. and are thus useful for low thermal budget applications. Also provided are MIM capacitor constructions and methods in which an insulator layer is formed by remote plasma oxidation of a bottom electrode.
    Type: Grant
    Filed: July 23, 2001
    Date of Patent: January 13, 2004
    Assignee: Applied Materials, Inc.
    Inventors: Pravin Narwankar, Mouloud Bakli, Ravi Rajagopalan, Randall S. Urdahl, Asher Sinensky, Shankarram Athreya
  • Patent number: 6617266
    Abstract: A process for forming high k dielectric thin films on a substrate, e.g., silicon, by 1) low temperature (500° C. or less) deposition of a dielectric material onto a surface, followed by 2) high temperature post-deposition annealing. The deposition can take place in an oxidative environment, followed by annealing, or alternatively the deposition can take place in a non-oxidative environment (e.g., N2), followed by oxidation and annealing.
    Type: Grant
    Filed: April 12, 2001
    Date of Patent: September 9, 2003
    Assignee: Applied Materials, Inc.
    Inventors: Annabel Susan Nickles, Ravi Rajagopalan, Pravin Narwankar
  • Patent number: 6548368
    Abstract: Provided is a method of integrating Ta2O5 into an MIS stack capacitor for a semiconductor device by forming a thin SiON layer at the Si/TaO interface using low temperature remote plasma oxidation anneal. Also provided is a method of forming an MIS stack capacitor with improved electrical performance by treating SiO2 with remote plasma nitridation or SiN layer with rapid thermal oxidation or RPO to form a SiON layer prior to Ta2O5 deposition with TAT-DMAE, TAETO or any other Ta-containing precursor.
    Type: Grant
    Filed: August 23, 2000
    Date of Patent: April 15, 2003
    Assignee: Applied Materials, Inc.
    Inventors: Pravin Narwankar, Ravi Rajagopalan
  • Publication number: 20030025146
    Abstract: The formation of a barrier layer over a high k dielectric layer and deposition of a conducting layer over the barrier layer prevents intermigration between the species of the high k dielectric layer and the conducting layer and prevents oxygen scavenging of the high k dielectric layer. One example of a capacitor stack device provided includes a high k dielectric layer of Ta2O5, a barrier layer of TaON or TiON formed at least in part by a remote plasma process, and a top electrode of TiN. The processes may be conducted at about 300 to 700° C. and are thus useful for low thermal budget applications. Also provided are MIM capacitor constructions and methods in which an insulator layer is formed by remote plasma oxidation of a bottom electrode.
    Type: Application
    Filed: July 23, 2001
    Publication date: February 6, 2003
    Inventors: Pravin Narwankar, Mouloud Bakli, Ravi Rajagopalan, Randall S. Urdahl, Asher Sinensky, Shankarram Athreya
  • Publication number: 20020173126
    Abstract: The present invention provides a means for obtaining dielectric thin films on a substrate, e.g., silicon, by 1) low temperature (500° C. or less) deposition of a dielectric material onto a surface, followed by 2) high temperature post-deposition annealing. The deposition can take place in an oxidative environment, followed by annealing, or alternatively the deposition can take place in a non-oxidative environment (e.g., N2), followed by oxidation and annealing.
    Type: Application
    Filed: April 12, 2001
    Publication date: November 21, 2002
    Applicant: Applied Materials, Inc.
    Inventors: Annabel Susan Nickles, Ravi Rajagopalan, Pravin Narwankar
  • Publication number: 20020168847
    Abstract: A method of providing a stable interface between a metallic layer and a dielectric layer in a semiconductor device is provided. The method includes generating a remote nitrogen containing plasma and flowing activated nitrogen species, from the remote site to the location of the metallic layer. The activated nitrogen species are flowed over at least the surface of the metallic layer, where they react with the metallic surface to form a metal nitride. The treated layer can be used to provide a stable bottom electrode in a capacitor stack formation.
    Type: Application
    Filed: May 9, 2001
    Publication date: November 14, 2002
    Applicant: Applied Materials, Inc.
    Inventors: Pravin Narwankar, Ravi Rajagopalan, Turgut Sahin
  • Patent number: 6274058
    Abstract: A processing chamber cleaning method is described which utilizes microwave energy to remotely generate a reactive species to be used alone or in combination with an inert gas to remove deposits from a processing chamber. The reactive species can remove deposits from a first processing region at a first pressure and then remove deposits from a second processing region at a second pressure. Also described is a cleaning process utilizing remotely generated reactive species in a single processing region at two different pressures. Additionally, different ratios of reactive gas and inert gas may be utilized to improve the uniformity of the cleaning process, increase the cleaning rate, reduce recombination of reactive species and increase the residence time of reactive species provided to the processing chamber.
    Type: Grant
    Filed: July 2, 1999
    Date of Patent: August 14, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Ravi Rajagopalan, Patricia M. Liu, Pravin K. Narwankar, Huyen Tran, Padmanabhan Krishnaraj, Alan Ablao, Tim Casper
  • Patent number: 6204174
    Abstract: A method and apparatus to control the deposition rate of a refractory metal film in a semiconductor fabrication process by controlling a quantity of ethylene present. The method includes placing a substrate in a deposition zone, of a semiconductor process chamber, flowing, into the deposition zone, a process gas including a refractory metal source, an inert carrier gas, and a hydrocarbon. Typically, the refractory metal source is tungsten hexafluoride, WF6, and the inert gas is argon, Ar. The ethylene may be premixed with either the argon or the tungsten hexafluoride to form a homogenous mixture. However, an in situ mixing apparatus may also be employed.
    Type: Grant
    Filed: November 25, 1997
    Date of Patent: March 20, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Alexander D. Glew, Andrew D. Johnson, Ravi Rajagopalan, Steve Ghanayem
  • Patent number: 6174373
    Abstract: An apparatus and process for limiting residue remaining after the etching of metal in a semiconductor manufacturing process, such as etching back a tungsten layer to form tungsten plugs, by passivating the surface of a wafer with a halogen-containing gas are disclosed. The wafer is exposed to the halogen-containing gas in a chamber before a metal layer is deposited on the wafer. The exposure can occur in the same chamber as the metal deposition, or a different chamber. The wafer can remain in the chamber or be moved to another chamber for etching after exposure and deposition.
    Type: Grant
    Filed: January 4, 2000
    Date of Patent: January 16, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Steve Ghanayem, Moris Kori, Maitreyee Mahajani, Ravi Rajagopalan
  • Patent number: 6156382
    Abstract: A multiple step chemical vapor deposition process for depositing a tungsten layer on a substrate. A first step of the deposition process includes a nucleation step in which WF.sub.6 and SiH.sub.4 are introduced into a deposition chamber. Next, the flow of WF.sub.6 and SiH.sub.4 are stopped and diborane is introduced into the chamber for between 5-25 seconds. Finally, during a bulk deposition step, the WF.sub.6 is reintroduced into the chamber along with H.sub.2 and B.sub.2 H.sub.6 flows to deposit a tungsten layer on the substrate. In a preferred embodiment, the bulk deposition step also introduces nitrogen into the process gas.
    Type: Grant
    Filed: May 16, 1997
    Date of Patent: December 5, 2000
    Assignee: Applied Materials, Inc.
    Inventors: Ravi Rajagopalan, Steve Ghanayem, Manabu Yamazaki, Keiichi Ohtsuka, Yuji Maeda
  • Patent number: 6070599
    Abstract: An apparatus and process for limiting residue remaining after the etching of metal in a semiconductor manufacturing process, such as etching back a tungsten layer to form tungsten plugs, by passivating the surface of a wafer with a halogen-containing gas are disclosed. The wafer is exposed to the halogen-containing gas in a chamber before a metal layer is deposited on the wafer. The exposure can occur in the same chamber as the metal deposition, or a different chamber. The wafer can remain in the chamber or be moved to another chamber for etching after exposure and deposition.
    Type: Grant
    Filed: October 2, 1997
    Date of Patent: June 6, 2000
    Assignee: Applied Materials, Inc
    Inventors: Steve Ghanayem, Moris Kori, Maitreyee Mahajani, Ravi Rajagopalan
  • Patent number: 5709772
    Abstract: An apparatus and process for limiting residue remaining after the etching of metal in a semiconductor manufacturing process by injecting a halogen-containing gas without a plasma into a processing chamber. The wafer is then exposed to the remnants of the halogen-containing gas in the chamber before the metal is deposited on the wafer. The exposure can occur in the same chamber as the metal deposition, or a different chamber. The wafer can remain in the chamber or be moved to another chamber for etching after exposure and deposition.
    Type: Grant
    Filed: March 29, 1996
    Date of Patent: January 20, 1998
    Assignee: Applied Materials, Inc.
    Inventors: Steve Ghanayem, Moris Kori, Maitreyee Mahajani, Ravi Rajagopalan