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: 9548348
    Abstract: Non-volatile memory cells including complimentary metal-oxide-semiconductor transistors and embedded ferroelectric capacitor and methods of forming the same are described. In one embodiment, the method includes forming on a surface of a substrate a gate level including a gate stack of a MOS transistor, a first dielectric layer overlying the MOS transistor and a first contact extending through the first dielectric layer from a top surface thereof to a diffusion region of the MOS transistor. A local interconnect (LI) layer is deposited over the top surface of the first dielectric layer and the first contact, a ferro stack including a bottom electrode, a top electrode and ferroelectric layer there between deposited over the LI layer, and the ferro stack and the LI layer patterned to form a ferroelectric capacitor and a LI through which the bottom electrode is electrically coupled to the diffusion region of the MOS transistor.
    Type: Grant
    Filed: December 17, 2013
    Date of Patent: January 17, 2017
    Assignee: Cypress Semiconductor Corporation
    Inventors: Shan Sun, Krishnaswamy Ramkumar, Thomas Davenport, Kedar Patel
  • Publication number: 20170005108
    Abstract: A method of making and structural embodiments of a semiconductor structure are provided. The method includes forming a tunneling layer over a channel connecting a source and a drain formed in a surface of a substrate, forming a charge storage layer overlying the tunneling layer, and forming a blocking structure on the charge storage layer by plasma oxidation. A thickness of the charge storage layer is reduced through oxidation of a portion of the charge storage layer during the formation of the blocking structure. Other embodiments are also described.
    Type: Application
    Filed: September 15, 2016
    Publication date: January 5, 2017
    Inventors: Jeong Soo Byun, Krishnaswamy Ramkumar
  • Patent number: 9502543
    Abstract: Methods of fabricating a memory device are described. Generally, the method begins with forming a tunnel dielectric layer over a channel region formed from a silicon containing layer over a surface of a substrate. A first oxygen-rich nitride layer of a multi-layer charge-trapping region is formed on a surface of the tunnel dielectric layer, and a second oxygen-lean nitride layer formed over the first nitride layer. A blocking dielectric layer is formed over a surface of the second layer of the multi-layer charge-trapping region, and a high work function gate electrode upon over the blocking dielectric layer. Other embodiments are also described.
    Type: Grant
    Filed: July 28, 2015
    Date of Patent: November 22, 2016
    Assignee: Cypress Semiconductor Corporation
    Inventors: Igor Polishchuk, Sagy Charel Levy, Krishnaswamy Ramkumar
  • Patent number: 9496144
    Abstract: A method of fabricating a memory device is described. Generally, the method includes: forming on a surface of a substrate a dielectric stack including a tunneling dielectric and a charge-trapping layer overlying the tunneling dielectric; depositing a first cap layer comprising an oxide over the dielectric stack; forming a second cap layer comprising a nitride over the first cap layer; patterning the first and second cap layers and the dielectric stack to form a gate stack of a memory device; removing the second cap layer; and performing an oxidation process to form a blocking oxide over the charge-trapping layer, wherein the oxidation process consumes the first cap layer. Other embodiments are also described.
    Type: Grant
    Filed: March 31, 2015
    Date of Patent: November 15, 2016
    Assignee: Cypress Semiconductor Corporation
    Inventors: Krishnaswamy Ramkumar, Hui-Mei Shih
  • Publication number: 20160308033
    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: June 22, 2016
    Publication date: October 20, 2016
    Inventors: Sagy LEVY, Krishnaswamy RAMKUMAR, Fredrick JENNE, Sam GEHA
  • Publication number: 20160308009
    Abstract: A charge trap memory device is provided. In one embodiment, the charge trap memory device includes a semiconductor material structure having a vertical channel extending from a first diffusion region formed in a semiconducting material to a second diffusion region formed over the first diffusion region, the vertical channel electrically connecting the first diffusion region to the second diffusion region. A tunnel dielectric layer is disposed on the vertical channel, a multi-layer charge-trapping region including a first deuterated layer disposed on the tunnel dielectric layer, a first nitride layer disposed on the first deuterated layer, and a second nitride layer comprising a deuterium-free trap-dense, oxygen-lean nitride disposed on the first nitride layer. The second nitride layer includes a majority of charge traps distributed in the multi-layer charge-trapping region.
    Type: Application
    Filed: June 22, 2016
    Publication date: October 20, 2016
    Inventors: Sagy LEVY, Fredrick JENNE, Krishnaswamy RAMKUMAR
  • Publication number: 20160300959
    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: February 23, 2016
    Publication date: October 13, 2016
    Inventors: Fredrick B. Jenne, Sagy Charel Levy, Krishnaswamy Ramkumar
  • Publication number: 20160300724
    Abstract: A semiconductor device including an oxide-nitride-oxide (ONO) structure having a multi-layer charge storing layer and methods of forming the same are provided. Generally, the method involves: (i) forming a first oxide layer of the ONO structure; (ii) forming a multi-layer charge storing layer comprising nitride on a surface of the first oxide layer; and (iii) forming a second oxide layer of the ONO structure on a surface of the multi-layer charge storing layer. Preferably, the charge storing layer comprises at least two silicon oxynitride layers having differing stochiometric compositions of Oxygen, Nitrogen and/or Silicon. More preferably, the ONO structure is part of a silicon-oxide-nitride-oxide-silicon (SONOS) structure and the semiconductor device is a SONOS memory transistor. Other embodiments are also disclosed.
    Type: Application
    Filed: April 14, 2016
    Publication date: October 13, 2016
    Inventors: Sagy Charel Levy, Krishnaswamy Ramkumar, Fredrick Jenne, Sam G. Geha
  • Patent number: 9460974
    Abstract: A method of making a semiconductor structure is provided. The method includes forming a tunneling layer overlying a first channel connecting a source and a drain. A charge storage layer is formed overlying the tunneling layer, the charge storage layer comprises forming a substantially trap free first layer over the tunneling layer, and forming a trap dense second layer over the first layer. Finally, a blocking structure is formed on the charge storage layer by plasma oxidation. A thickness of the charge storage layer is reduced through oxidation of a portion of the charge storage layer during the formation of the blocking structure. Other embodiments are also described.
    Type: Grant
    Filed: December 15, 2015
    Date of Patent: October 4, 2016
    Assignee: Cypress Semiconductor Corporation
    Inventors: Jeong Soo Byun, Krishnaswamy Ramkumar
  • Patent number: 9449831
    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: Grant
    Filed: March 31, 2012
    Date of Patent: September 20, 2016
    Assignee: Cypress Semiconductor Corporation
    Inventors: Sagy Levy, Krishnaswamy Ramkumar, Fredrick Jenne, Sam Geha
  • Publication number: 20160260730
    Abstract: Memory devices and methods for forming the same are disclosed. In one embodiment, the device includes a non-volatile memory (NVM) transistor formed in a first region of a substrate, the NVM transistor comprising a channel and a gate stack on the substrate overlying the channel. The gate stack includes a dielectric layer on the substrate, a charge-trapping layer on the dielectric layer, an oxide layer overlying the charge-trapping layer, a first gate overlying the oxide layer, and a first silicide region overlying the first gate. The device includes a metal-oxide-semiconductor transistor formed in a second region of the substrate comprising a gate oxide overlying the substrate in the second region, a second gate overlying the gate oxide, and a second silicide region overlying the second gate. A strain inducing structure overlies at least the NVM transistor and a surface of the substrate in the first region of the substrate.
    Type: Application
    Filed: May 4, 2016
    Publication date: September 8, 2016
    Inventors: Krishnaswamy Ramkumar, Igor G. Kouznetsov, Venkatraman Prabhakar
  • Patent number: 9431549
    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: Grant
    Filed: March 31, 2012
    Date of Patent: August 30, 2016
    Assignee: Cypress Semiconductor Corporation
    Inventors: Igor Polishchuk, Sagy Levy, Krishnaswamy Ramkumar
  • Patent number: 9406574
    Abstract: A method of making a semiconductor structure is provided. The method includes forming a tunneling layer over a channel connecting a source and a drain formed in a surface of a substrate, forming a charge storage layer overlying the tunneling layer, and forming a blocking structure on the charge storage layer by plasma oxidation. A thickness of the charge storage layer is reduced through oxidation of a portion of the charge storage layer during the formation of the blocking structure. Other embodiments are also described.
    Type: Grant
    Filed: December 5, 2014
    Date of Patent: August 2, 2016
    Assignee: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Jeong Soo Byun, Krishnaswamy Ramkumar
  • Publication number: 20160204120
    Abstract: Methods of integrating complementary SONOS devices into a CMOS process flow are described. In one embodiment, the method begins with depositing a hardmask (HM) over a substrate including a first-SONOS region and a second-SONOS region. A first tunnel mask (TUNM) is formed over the HM exposing a first portion of the HM in the second-SONOS region. The first portion of the HM is etched, a channel for a first SONOS device implanted through a first pad oxide overlying the second-SONOS region and the first TUNM removed. A second TUNM is formed exposing a second portion of the HM in the first-SONOS region. The second portion of the HM is etched, a channel for a second SONOS device implanted through a second pad oxide overlying the first-SONOS region and the second TUNM removed. The first and second pad oxides are concurrently etched, and the HM removed.
    Type: Application
    Filed: March 22, 2016
    Publication date: July 14, 2016
    Inventors: Venkatraman Prabhakar, Krishnaswamy Ramkumar, Igor Kouznetsov
  • Patent number: 9355725
    Abstract: A memory structure including a memory array of a plurality of memory cells arranged in rows and columns, the plurality of memory cells including a pair of adjacent memory cells in a row of the memory array, wherein the pair of adjacent memory cells include a single, shared source-line through which each of the memory cells in the pair of adjacent memory cells is coupled to a voltage source. Methods of operating a memory including the memory structure are also described.
    Type: Grant
    Filed: December 11, 2014
    Date of Patent: May 31, 2016
    Assignee: Cypress Semiconductor Corporation
    Inventors: Bo Jin, Krishnaswamy Ramkumar, Xiaojun Yu, Igor Kouznetsov, Venkatraman Prabhakar
  • Patent number: 9355849
    Abstract: A semiconductor device including an oxide-nitride-oxide (ONO) structure having a multi-layer charge storing layer and methods of forming the same are provided. Generally, the method involves: (i) forming a first oxide layer of the ONO structure; (ii) forming a multi-layer charge storing layer comprising nitride on a surface of the first oxide layer; and (iii) forming a second oxide layer of the ONO structure on a surface of the multi-layer charge storing layer. Preferably, the charge storing layer comprises at least two silicon oxynitride layers having differing stochiometric compositions of Oxygen, Nitrogen and/or Silicon. More preferably, the ONO structure is part of a silicon-oxide-nitride-oxide-silicon (SONOS) structure and the semiconductor device is a SONOS memory transistor. Other embodiments are also disclosed.
    Type: Grant
    Filed: June 13, 2013
    Date of Patent: May 31, 2016
    Assignee: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Sagy Charel Levy, Krishnaswamy Ramkumar, Fredrick B. Jenne, Sam G. Geha
  • Patent number: 9356035
    Abstract: A memory device that includes a non-volatile memory (NVM) transistor which has an indium doped channel and a gate stack overlying the channel formed in a first region of a substrate and a metal-oxide-semiconductor (MOS) transistor formed in a second region of the substrate in which the gate oxide of the MOS and the oxide layer of the NVM transistor are formed concurrently.
    Type: Grant
    Filed: August 4, 2014
    Date of Patent: May 31, 2016
    Assignee: Cypress Semiconductor Corporation
    Inventors: Krishnaswamy Ramkumar, Igor G. Kouznetsov, Venkatraman Prabhakar
  • Patent number: 9349877
    Abstract: A nonvolatile trapped-charge memory device and method of fabricating the same are described. Generally, the memory device includes a tunneling layer on a substrate, a charge trapping layer on the tunneling layer, and a blocking layer on the charge trapping layer. The tunneling layer includes a nitrided oxide film formed by annealling an oxide grown on the substrate using a nitrogen source. The tunneling layer comprises a first region proximate to the substrate, and a second region proximate to the charge trapping layer, and wherein the nitrogen concentration decreases from a first interface between the second region and the charge trapping layer to a second interface between the first region and the substrate to reduce nitrogen trap density at the second interface. Other embodiments are also described.
    Type: Grant
    Filed: January 28, 2014
    Date of Patent: May 24, 2016
    Assignee: Cypress Semiconductor Corporation
    Inventors: Sagy Charel Levy, Krishnaswamy Ramkumar, Frederick B. Jenne
  • Patent number: 9349824
    Abstract: A method of fabricating a memory device is described. Generally, the method includes: forming a tunneling layer on a substrate; forming on the tunneling layer a multi-layer charge storing layer including at least a first charge storing layer comprising an oxygen-rich oxynitride overlying the tunneling layer, and a second charge storing layer overlying the first charge storing layer comprising a silicon-rich and nitrogen-rich oxynitride layer that is oxygen-lean relative to the first charge storing layer and comprises a majority of charge traps distributed in the multi-layer charge storing layer; and forming a blocking layer on the second oxynitride layer; and forming a gate layer on the blocking layer. Other embodiments are also described.
    Type: Grant
    Filed: February 4, 2014
    Date of Patent: May 24, 2016
    Assignee: CYPRESS SEMICONDUCTOR CORPORATION
    Inventors: Sagy Charel Levy, Krishnaswamy Ramkumar, Frederick B. Jenne, Sam G Geha
  • Publication number: 20160141180
    Abstract: A semiconductor device includes a polysilicon substrate, a first oxide layer formed on the polysilicon substrate, an oxygen-rich nitride layer formed on the first oxide layer, a second oxide layer formed on the oxygen-rich nitride layer, and an oxygen-poor nitride layer formed on the second oxide layer.
    Type: Application
    Filed: August 11, 2015
    Publication date: May 19, 2016
    Inventors: Fredrick B. Jenne, Krishnaswamy Ramkumar