Patents by Inventor Krishnaswamy Ramkumar

Krishnaswamy Ramkumar 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: 8680601
    Abstract: A nonvolatile charge trap memory device is described. The device includes a substrate having a channel region and a pair of source/drain regions. A gate stack is above the substrate over the channel region and between the pair of source/drain regions. The gate stack includes a multi-layer charge-trapping region having a first deuterated layer. The multi-layer charge-trapping region may further include a deuterium-free charge-trapping layer.
    Type: Grant
    Filed: September 26, 2007
    Date of Patent: March 25, 2014
    Assignee: Cypress Semiconductor Corporation
    Inventors: Sagy Levy, Fredrick B. Jenne, Krishnaswamy Ramkumar
  • Patent number: 8679927
    Abstract: A semiconductor structure and method to form the same. The semiconductor structure includes a substrate having a non-volatile charge trap memory device disposed on a first region and a logic device disposed on a second region. A charge trap dielectric stack may be formed subsequent to forming wells and channels of the logic device. HF pre-cleans and SC1 cleans may be avoided to improve the quality of a blocking layer of the non-volatile charge trap memory device. The blocking layer may be thermally reoxidized or nitridized during a thermal oxidation or nitridation of a logic MOS gate insulator layer to densify the blocking layer. A multi-layered liner may be utilized to first offset a source and drain implant in a high voltage logic device and also block silicidation of the nonvolatile charge trap memory device.
    Type: Grant
    Filed: August 4, 2008
    Date of Patent: March 25, 2014
    Assignee: Cypress Semiconductor Corporation
    Inventors: Krishnaswamy Ramkumar, Fredrick B. Jenne, Sagy Levy
  • Patent number: 8643124
    Abstract: A semiconductor device including a silicon-oxide-oxynitride-oxide-silicon structure and methods of forming the same are provided. Generally, the structure comprises: a tunnel oxide layer on a surface of a substrate including silicon; a multi-layer charge storing layer including an oxygen-rich, first oxynitride layer on the tunnel oxide layer in which the stoichiometric composition of the first oxynitride layer results in it being substantially trap free, and an oxygen-lean, second oxynitride layer on the first oxynitride layer in which the stoichiometric composition of the second oxynitride layer results in it being trap dense; a blocking oxide layer on the second oxynitride layer; and a silicon containing gate layer on the blocking oxide layer. Other embodiments are also disclosed.
    Type: Grant
    Filed: January 14, 2011
    Date of Patent: February 4, 2014
    Assignee: Cypress Semiconductor Corporation
    Inventors: Sagy Levy, Krishnaswamy Ramkumar, Fredrick Jenne, Sam Geha
  • Patent number: 8637921
    Abstract: A method for forming a tunneling layer of a nonvolatile trapped-charge memory device and the article made thereby. The method includes multiple oxidation and nitridation operations to provide a dielectric constant higher than that of a pure silicon dioxide tunneling layer but with a fewer hydrogen and nitrogen traps than a tunneling layer having nitrogen at the substrate interface. The method provides for an improved memory window in a SONOS-type device. In one embodiment, the method includes an oxidation, a nitridation, a reoxidation and a renitridation. In one implementation, the first oxidation is performed with O2 and the reoxidation is performed with NO.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: January 28, 2014
    Assignee: Cypress Semiconductor Corporation
    Inventors: Sagy Levy, Krishnaswamy Ramkumar, Fredrick B. Jenne
  • Patent number: 8633537
    Abstract: A semiconductor devices including non-volatile memories and methods of fabricating the same to improve performance thereof are provided. Generally, the device includes a memory transistor comprising a polysilicon channel region electrically connecting a source region and a drain region formed in a substrate, an oxide-nitride-nitride-oxide (ONNO) stack disposed above the channel region, and a high work function gate electrode formed over a surface of the ONNO stack. In one embodiment the ONNO stack includes a multi-layer charge-trapping region including an oxygen-rich first nitride layer and an oxygen-lean second nitride layer disposed above the first nitride layer. Other embodiments are also disclosed.
    Type: Grant
    Filed: July 1, 2012
    Date of Patent: January 21, 2014
    Assignee: Cypress Semiconductor Corporation
    Inventors: Igor Polishchuk, Sagy Levy, Krishnaswamy Ramkumar
  • Patent number: 8592891
    Abstract: A semiconductor device and method of fabricating the same are provided. In one embodiment, the semiconductor device includes a memory transistor with an oxide-nitride-nitride-oxide (ONNO) stack disposed above a channel region. The ONNO stack comprises a tunnel dielectric layer disposed above the channel region, a multi-layer charge-trapping region disposed above the tunnel dielectric layer, and a blocking dielectric layer disposed above the multi-layer charge-trapping region. The multi-layer charge-trapping region includes a substantially trap-free layer comprising an oxygen-rich nitride and a trap-dense layer disposed above the trap-free layer. The semiconductor device further includes a strain inducing structure including a strain inducing layer disposed proximal to the ONNO stack to increase charge retention of the multi-layer charge-trapping region. Other embodiments are also disclosed.
    Type: Grant
    Filed: July 1, 2012
    Date of Patent: November 26, 2013
    Assignee: Cypress Semiconductor Corp.
    Inventors: Igor Polishchuk, Sagy Levy, Krishnaswamy Ramkumar, Jeong Byun
  • Publication number: 20130306975
    Abstract: Scaling a charge trap memory device and the article made thereby. In one embodiment, the charge trap memory device includes a substrate having a source region, a drain region, and a channel region electrically connecting the source and drain. A tunnel dielectric layer is disposed above the substrate over the channel region, and a multi-layer charge-trapping region disposed on the tunnel dielectric layer.
    Type: Application
    Filed: July 1, 2012
    Publication date: November 21, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Sagy LEVY, Fredrick JENNE, Krishnaswamy RAMKUMAR
  • Publication number: 20130309826
    Abstract: A method for fabricating a nonvolatile charge trap memory device is described. The method includes subjecting a substrate to a first oxidation process to form a tunnel oxide layer overlying a polysilicon channel, and forming over the tunnel oxide layer a multi-layer charge storing layer comprising an oxygen-rich, first layer comprising a nitride, and an oxygen-lean, second layer comprising a nitride on the first layer. The substrate is then subjected to a second oxidation process to consume a portion of the second layer and form a high-temperature-oxide (HTO) layer overlying the multi-layer charge storing layer. The stoichiometric composition of the first layer results in it being substantially trap free, and the stoichiometric composition of the second layer results in it being trap dense. The second oxidation process can comprise a plasma oxidation process or a radical oxidation process using In-Situ Steam Generation.
    Type: Application
    Filed: July 1, 2012
    Publication date: November 21, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Krishnaswamy RAMKUMAR, Sagy LEVY, Jeong BYUN
  • Publication number: 20130307053
    Abstract: A semiconductor devices including non-volatile memories and methods of fabricating the same to improve performance thereof are provided. Generally, the device includes a memory transistor comprising a polysilicon channel region electrically connecting a source region and a drain region formed in a substrate, an oxide-nitride-nitride-oxide (ONNO) stack disposed above the channel region, and a high work function gate electrode formed over a surface of the ONNO stack. In one embodiment the ONNO stack includes a multi-layer charge-trapping region including an oxygen-rich first nitride layer and an oxygen-lean second nitride layer disposed above the first nitride layer. Other embodiments are also disclosed.
    Type: Application
    Filed: July 1, 2012
    Publication date: November 21, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Igor POLISHCHUK, Sagy LEVY, Krishnaswamy RAMKUMAR
  • Publication number: 20130307052
    Abstract: A method of scaling a nonvolatile trapped-charge memory device and the device made thereby is provided. In an embodiment, the method includes forming a channel region including polysilicon electrically connecting a source region and a drain region in a substrate. A tunneling layer is formed on the substrate over the channel region by oxidizing the substrate to form an oxide film and nitridizing the oxide film. A multi-layer charge trapping layer including an oxygen-rich first layer and an oxygen-lean second layer is formed on the tunneling layer, and a blocking layer deposited on the multi-layer charge trapping layer. In one embodiment, the method further includes a dilute wet oxidation to densify a deposited blocking oxide and to oxidize a portion of the oxygen-lean second layer.
    Type: Application
    Filed: July 1, 2012
    Publication date: November 21, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Fredrick JENNE, Sagy LEVY, Krishnaswamy RAMKUMAR
  • Patent number: 8536640
    Abstract: A nonvolatile charge trap memory device with deuterium passivation of charge traps and method of manufacture. Deuterated gate layer, deuterated gate cap layer and deuterated spacers are employed in various combinations to encapsulate the device with deuterium sources proximate to the interfaces within the gate stack and on the surface of the gate stack where traps may be present.
    Type: Grant
    Filed: September 26, 2007
    Date of Patent: September 17, 2013
    Assignee: Cypress Semiconductor Corporation
    Inventors: Krishnaswamy Ramkumar, Fredrick B. Jenne, William W. Koutny
  • Publication number: 20130210209
    Abstract: Embodiments of a method of integration of a non-volatile memory device into a MOS flow are described. Generally, the method includes: forming a dielectric stack on a surface of a substrate, the dielectric stack including a tunneling dielectric overlying the surface of the substrate and a charge-trapping layer overlying the tunneling dielectric; forming a cap layer overlying the dielectric stack; patterning the cap layer and the dielectric stack to form a gate stack of a memory device in a first region of the substrate and to remove the cap layer and the charge-trapping layer from a second region of the substrate; and performing an oxidation process to form a gate oxide of a MOS device overlying the surface of the substrate in the second region while simultaneously oxidizing the cap layer to form a blocking oxide overlying the charge-trapping layer. Other embodiments are also disclosed.
    Type: Application
    Filed: March 23, 2012
    Publication date: August 15, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventor: Krishnaswamy Ramkumar
  • Publication number: 20130175600
    Abstract: Embodiments of a non-planar memory device including a split charge-trapping region and methods of forming the same are described. Generally, the device comprises: a channel formed from a thin film of semiconducting material overlying a surface on a substrate connecting a source and a drain of the memory device; a tunnel oxide overlying the channel; a split charge-trapping region overlying the tunnel oxide, the split charge-trapping region including a bottom charge-trapping layer comprising a nitride closer to the tunnel oxide, and a top charge-trapping layer, wherein the bottom charge-trapping layer is separated from the top charge-trapping layer by a thin anti-tunneling layer comprising an oxide. Other embodiments are also disclosed.
    Type: Application
    Filed: March 27, 2012
    Publication date: July 11, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Fredrick Jenne, Krishnaswamy Ramkumar
  • Publication number: 20130175504
    Abstract: An embodiment of a semiconductor memory device including a multi-layer charge storing layer and methods of forming the same are described. Generally, the device includes a channel formed from a semiconducting material overlying a surface on a substrate connecting a source and a drain of the memory device; a tunnel oxide layer overlying the channel; and a multi-layer charge storing layer including an oxygen-rich, first oxynitride layer on the tunnel oxide layer in which a stoichiometric composition of the first oxynitride layer results in it being substantially trap free, and an oxygen-lean, second oxynitride layer on the first oxynitride layer in which a stoichiometric composition of the second oxynitride layer results in it being trap dense. In one embodiment, the device comprises a non-planar transistor including a gate having multiple surfaces abutting the channel, and the gate comprises the tunnel oxide layer and the multi-layer charge storing layer.
    Type: Application
    Filed: March 31, 2012
    Publication date: July 11, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Sagy Levy, Krishnaswamy Ramkumar, Fredrick Jenne, Sam Geha
  • Publication number: 20130178030
    Abstract: An embodiment of a method of integration of a non-volatile memory device into a logic MOS flow is described. Generally, the method includes: forming a pad dielectric layer of a MOS device above a first region of a substrate; forming a channel of the memory device from a thin film of semiconducting material overlying a surface above a second region of the substrate, the channel connecting a source and drain of the memory device; forming a patterned dielectric stack overlying the channel above the second region, the patterned dielectric stack comprising a tunnel layer, a charge-trapping layer, and a sacrificial top layer; simultaneously removing the sacrificial top layer from the second region of the substrate, and the pad dielectric layer from the first region of the substrate; and simultaneously forming a gate dielectric layer above the first region of the substrate and a blocking dielectric layer above the charge-trapping layer.
    Type: Application
    Filed: March 29, 2012
    Publication date: July 11, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Krishnaswamy Ramkumar, Bo Jin, Fredrick Jenne
  • Publication number: 20130175604
    Abstract: An embodiment of a nonvolatile charge trap memory device is described. In one embodiment, the device comprises a channel comprising silicon overlying a surface on a substrate electrically connecting a first diffusion region and a second diffusion region of the memory device, and a gate stack intersecting and overlying at least a portion of the channel, the gate stack comprising a tunnel oxide abutting the channel, a split charge-trapping region abutting the tunnel oxide, and a multi-layer blocking dielectric abutting the split charge-trapping region. The split charge-trapping region includes a first charge-trapping layer comprising a nitride closer to the tunnel oxide, and a second charge-trapping layer comprising a nitride overlying the first charge-trapping layer. The multi-layer blocking dielectric comprises at least a high-K dielectric layer.
    Type: Application
    Filed: March 31, 2012
    Publication date: July 11, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Igor Polishchuk, Sagy Levy, Krishnaswamy Ramkumar
  • Publication number: 20130175599
    Abstract: Embodiments of structures and methods for determining operating characteristics of a non-volatile memory transistor comprising a charge-storage-layer and a tunneling-layer are described.
    Type: Application
    Filed: March 26, 2012
    Publication date: July 11, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Yu Yang, Krishnaswamy Ramkumar
  • Publication number: 20130178031
    Abstract: An embodiment of a method of integrating a non-volatile memory device into a logic MOS flow is described. Generally, the method includes: forming in a first region of a substrate a channel of a memory device from a semiconducting material overlying a surface of the substrate, the channel connecting a source and a drain of the memory device; forming a charge trapping dielectric stack over the channel adjacent to a plurality of surfaces of the channel, wherein the charge trapping dielectric stack includes a blocking layer on a charge trapping layer over a tunneling layer; and forming a MOS device over a second region of the substrate.
    Type: Application
    Filed: March 31, 2012
    Publication date: July 11, 2013
    Applicant: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Krishnaswamy Ramkumar, Fredrick Jenne, Sagy Levy
  • Patent number: 8445381
    Abstract: A method of making a semiconductor structure comprises forming an oxide layer on a substrate; forming a silicon nitride layer on the oxide layer; annealing the layers in NO; and annealing the layers in ammonia. The equivalent oxide thickness of the oxide layer and the silicon nitride layer together is at most 25 Angstroms.
    Type: Grant
    Filed: December 20, 2007
    Date of Patent: May 21, 2013
    Assignee: Cypress Semiconductor Corporation
    Inventors: Krishnaswamy Ramkumar, Sundar Narayanan
  • Patent number: 8318608
    Abstract: A method for fabricating a nonvolatile charge trap memory device is described. The method includes providing a substrate having a charge-trapping layer disposed thereon. A portion of the charge-trapping layer is then oxidized to form a blocking dielectric layer above the charge-trapping layer by exposing the charge-trapping layer to a radical oxidation process.
    Type: Grant
    Filed: August 25, 2008
    Date of Patent: November 27, 2012
    Assignee: Cypress Semiconductor Corporation
    Inventors: Krishnaswamy Ramkumar, Sagy Levy, Jeong Byun