Patents by Inventor A. Srinivas

A. Srinivas 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).

  • Publication number: 20040014315
    Abstract: Methods for the deposition of tungsten films are provided. The methods include depositing a nucleation layer by alternatively adsorbing a tungsten precursor and a reducing gas on a substrate, and depositing a bulk layer of tungsten over the nucleation layer.
    Type: Application
    Filed: November 18, 2002
    Publication date: January 22, 2004
    Applicant: Applied Materials, Inc.
    Inventors: Ken K. Lai, Jeong Soo Byun, Frederick C. Wu, Ramanujapuran A. Srinivas, Avgerinos Gelatos, Mei Chang, Moris Kori, Ashok K. Sinha, Hua Chung, Hongbin Fang, Alfred W. Mak, Michael X. Yang, Ming Xi
  • Patent number: 6573181
    Abstract: A method of forming a contact in an integrated circuit including forming a dielectric layer over a silicon substrate, etching a contact hole through the dielectric layer, exposing the etched contact hole to a plasma formed from a preclean gas comprising nitrogen trifluoride and helium and, thereafter, depositing a titanium layer within the contact hole by a plasma CVD process, where the plasma CVD process heats the substrate to a temperature less than or equal to 650° C.
    Type: Grant
    Filed: October 26, 2000
    Date of Patent: June 3, 2003
    Assignee: Applied Materials, Inc.
    Inventors: Ramanujapuram A. Srinivas, Mohan K. Bhan, Jennifer Kopp
  • Patent number: 6548402
    Abstract: A method of forming a titanium nitride (TiN) layer using a reaction between ammonia (NH3) and titanium tetrachloride (TiCl4). In one embodiment, an NH3:TiCl4 ratio of about 8.5 is used to deposit a TiN layer at a temperature of about 500° C. at a pressure of about 20 torr. In another embodiment, a composite TiN layer is formed by alternately depositing TiN layers of different thicknesses, using process conditions having different NH3:TiCl4 ratios. In one preferred embodiment, a TiN layer of less than about 20 Å is formed at an NH3:TiCl4 ratio of about 85, followed by a deposition of a thicker TiN layer at an NH3:TiCl4 ratio of about 8.5. By repeating the alternate film deposition using the two different process conditions, a composite TiN layer is formed. This composite TiN layer has an improved overall step coverage and reduced stress, compared to a standard TiN process, and is suitable for small geometry plug fill applications.
    Type: Grant
    Filed: June 11, 1999
    Date of Patent: April 15, 2003
    Assignee: Applied Materials, Inc.
    Inventors: Shulin Wang, Ming Xi, Frederick Wu, Ramanujapuram A. Srinivas, Yehuda Demayo, Zvi Lando, Mei Chang, Russell C. Ellwanger
  • Publication number: 20030049931
    Abstract: Refractory metal nitride layers for integrated circuit fabrication are described. The refractory metal nitride layer may be formed by sequentially chemisorbing alternating monolayers of a nitrogen-containing compound and a refractory metal compound onto a substrate. A composite refractory metal nitride layer is also described. The composite refractory metal nitride layer may be formed by sequentially chemisorbing monolayers of a nitrogen-containing compound and two or more refractory metal compounds onto a substrate.
    Type: Application
    Filed: September 19, 2001
    Publication date: March 13, 2003
    Applicant: APPLIED MATERIALS, INC.
    Inventors: Jeong Soo Byun, Lin Yin, Frederick C. Wu, Ramanujapuram A. Srinivas, Avgerinos Gelatos, Alfred W. Mak, Mei Chang, Moris Kori, Ashok K. Sinha
  • Patent number: 6524952
    Abstract: A method of forming a silicide layer in contact with a silicon substrate. The method comprises forming the silicide layer by supplying a silicon-containing source that is different from the silicon substrate, such that the silicon in the silicide layer originates primarily from the silicon-containing source.
    Type: Grant
    Filed: June 20, 2000
    Date of Patent: February 25, 2003
    Assignee: Applied Materials, Inc.
    Inventors: Ramanujapuram A. Srinivas, Brian Metzger, Shulin Wang, Frederick C. Wu
  • Publication number: 20020192396
    Abstract: A method of forming a film structure (e.g., film stack) comprising titanium (Ti) and titanium nitride (TiN) films is disclosed. In one aspect of the invention, a titanium silicide (TiSix) layer is formed on a Ti film, followed by deposition of a TiN film on the TiSix layer. The TiSix layer protects the underlying Ti film from chemical attack by TiCl4-based chemistry during subsequent TiN layer deposition. In another aspect of the invention, a cap layer of TiN is deposited between the Ti and TiN layers of a Ti/TiN film structure. The TiN cap layer inhibits chlorine migration from the overlying TiN layer into an underlying contact region, such as, for example, the source or drain of a transistor.
    Type: Application
    Filed: May 11, 2000
    Publication date: December 19, 2002
    Inventors: Shulin Wang, Mei Chang, Ramanujapuram A. Srinivas, Avgerinos Gelatos
  • Patent number: 6482746
    Abstract: A method for the in situ cleaning of a semiconductor deposition chamber utilized for the deposition of a semiconductor material such as titanium or titanium nitride comprising, between wafers, introducing chlorine gas into the chamber at elevated temperature, purging the chamber with an inert gas and evacuating it before introduction of the next wafer. A two-stage between wafer cleaning process is carried out by introducing chlorine into the chamber at elevated temperature, thereafter initiating a plasma without removing the chlorine, purging the chamber with an inert gas and evacuating it before introduction of the next wafer. In a preferred embodiment, a thin protective film of titanium is deposited on the inner sur aces of the chamber prior to utilizing the chamber for he deposition of such material. The protective layer is replenished following each two-stage cleaning.
    Type: Grant
    Filed: June 5, 2001
    Date of Patent: November 19, 2002
    Assignee: Applied Materials, Inc.
    Inventors: Anand Vasudev, Toshio Itoh, Ramamujapuram A. Srinivas, Frederick Wu, Li Wu, Brian Boyle, Mei Chang
  • Patent number: 6432479
    Abstract: Method for passivating a layer of titanium that has been deposited on a substrate in a reaction chamber to coat the titanium thereby reducing the likelihood of contamination by byproducts of the deposition process or ambient oxygen or similar reactants. The method includes adding a flow of hydrogen and a flow of nitrogen to the chamber. The flows of hydrogen and nitrogen are approximately 800 sccm and continue for approximately 10-30 seconds respectively. The method may further comprise the step of forming a nitrogen plasma in the chamber for approximately 10 seconds wherein such case the flows of hydrogen and nitrogen continue for approximately 8 seconds respectively. The plasma is formed by applying RF power to an electrode located within said chamber or by a remote plasma source and channeled to said reactor chamber. Alternately, the passivation layer may be formed just by using a nitrogen plama alone for approximately 10-30 seconds at the same RF power level.
    Type: Grant
    Filed: October 29, 1998
    Date of Patent: August 13, 2002
    Assignee: Applied Materials, Inc.
    Inventors: Mei Chang, Ramanujapuram A. Srinivas, Li Wu
  • Publication number: 20010027030
    Abstract: A method for the in situ cleaning of a semiconductor deposition chamber utilized for the deposition of a semiconductor material such as titanium or titanium nitride comprising, between wafers, introducing chlorine gas into the chamber at elevated temperature, purging the chamber with an inert gas and evacuating it before introduction of the next wafer. A two-stage between wafer cleaning process is carried out by introducing chlorine into the chamber at elevated temperature, thereafter initiating a plasma without removing the chlorine, purging the chamber with an inert gas and evacuating it before introduction of the next wafer. In a preferred embodiment, a thin protective film of titanium is deposited on the inner surfaces of the chamber prior to utilizing the chamber for the deposition of such material. The protective layer is replenished following each two-stage cleaning.
    Type: Application
    Filed: June 5, 2001
    Publication date: October 4, 2001
    Applicant: Applied Materials, Inc.
    Inventors: Anand Vasudev, Toshio Itoh, Ramamujapuram A. Srinivas, Frederick Wu, Li Wu, Brian Boyle, Mei Chang
  • Patent number: 6242347
    Abstract: A method for the in situ cleaning of a semiconductor deposition chamber utilized for the deposition of a semiconductor material such as titanium or titanium nitride comprising, between wafers, introducing chlorine gas into the chamber at elevated temperature, purging the chamber with an inert gas and evacuating it before introduction of the next wafer. A two-stage between wafer cleaning process is carried out by introducing chlorine into the chamber at elevated temperature, thereafter initiating a plasma without removing the chlorine, purging the chamber with an inert gas and evacuating it before introduction of the next wafer. In a preferred embodiment, a thin protective film of titanium is deposited on the inner surfaces of the chamber prior to utilizing the chamber for the deposition of such material. The protective layer is replenished following each two-stage cleaning.
    Type: Grant
    Filed: September 30, 1998
    Date of Patent: June 5, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Anand Vasudev, Toshio Itoh, Ramanujapuram A. Srinivas, Frederick Wu, Li Wu, Brian Boyle, Mei Chang
  • Patent number: 6193813
    Abstract: A method of processing a substrate, such as a semiconductor wafer, in a vacuum processing chamber includes the steps of depositing a material on a surface of the substrate using a gas mixture, and purging the chamber of residual gases by flowing SiH4 into the chamber. Preferably, WSix is deposited on a semiconductor wafer using a mixture comprising WF6, dichlorosilane and a noble gas, and the chamber is subsequently purged of residual WF6 and dichlorosilane by flowing SiH4 into the chamber. A further method of processing a substrate in a vacuum processing chamber includes the step of conditioning the chamber by flowing SiH4 into the chamber prior to depositing a material on the surface of the substrate. Semiconductor wafers processed according to the inventive method are characterized by more uniform sheet resistance values and reduced film stress.
    Type: Grant
    Filed: September 28, 1998
    Date of Patent: February 27, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Meng Chu Tseng, Mei Chang, Ramanujapuram A. Srinivas, Klaus-Dieter Rinnen, Moshe Eizenberg, Susan Telford
  • Patent number: 5940733
    Abstract: Described is an improved polysilicon/tungsten silicide (WSi.sub.x) composite layer formed over an integrated circuit structure on a semiconductor wafer and characterized by improved step coverage and non tungsten-rich tungsten:silicon ratio of the WSi.sub.x layer, and a method of forming same. A doped layer of polysilicon is formed in a first deposition chamber over an integrated circuit structure previously formed on a semiconductor substrate and a capping layer of undoped polysilicon is then deposited in the first deposition chamber over the doped polysilicon layer. The substrate is then transferred from the first deposition chamber into a second deposition chamber without exposing the surface of the polysilicon layer to an oxidizing media.
    Type: Grant
    Filed: July 29, 1997
    Date of Patent: August 17, 1999
    Assignee: Applied Materials, Inc.
    Inventors: Israel Beinglass, Ramanujapuram A. Srinivas
  • Patent number: 5817576
    Abstract: A method of processing a substrate, such as a semiconductor wafer, in a vacuum processing chamber includes the steps of depositing a material on a surface of the substrate using a gas mixture, and purging the chamber of residual gases by flowing SiH.sub.4 into the chamber. Preferably, WSi.sub.x is deposited on a semiconductor wafer using a mixture comprising WF.sub.6, dichlorosilane and a noble gas, and the chamber is subsequently purged of residual WF.sub.6 and dichlorosilane by flowing SiH.sub.4 into the chamber. A further method of processing a substrate in a vacuum processing chamber includes the step of conditioning the chamber by flowing SiH.sub.4 into the chamber prior to depositing a material on the surface of the substrate. Semiconductor wafers processed according to the inventive method are characterized by more uniform sheet resistance values and reduced film stress.
    Type: Grant
    Filed: November 5, 1996
    Date of Patent: October 6, 1998
    Assignee: Applied Materials, Inc.
    Inventors: Meng Chu Tseng, Mei Chang, Ramanujapuram A. Srinivas, Klaus-Dieter Rinnen, Moshe Eizenberg, Susan Telford
  • Patent number: 5780360
    Abstract: A method of processing a substrate, such as a semiconductor wafer, in a vacuum processing chamber includes the steps of depositing a material on a surface of the substrate using a gas mixture, and purging the chamber of residual gases by flowing SiH.sub.4 into the chamber. Preferably, WSi.sub.x is deposited on a semiconductor wafer using a mixture comprising WF.sub.6, dichlorosilane and a noble gas, and the chamber is subsequently purged of residual WF.sub.6 and dichlorosilane by flowing SiH.sub.4 into the chamber. A further method of processing a substrate in a vacuum processing chamber includes the step of conditioning the chamber by flowing SiH.sub.4 into the chamber prior to depositing a material on the surface of the substrate. Semiconductor wafers processed according to the inventive method are characterized by more uniform sheet resistance values and reduced film stress.
    Type: Grant
    Filed: June 20, 1996
    Date of Patent: July 14, 1998
    Assignee: Applied Materials, Inc.
    Inventors: Jennifer Meng Chu Tseng, Mei Chang, Ramanujapuram A. Srinivas, Klaus-Dieter Rinnen, Moshe Eizenberg, Susan Weihar Telford