Patents by Inventor Gowrishankar Chindalore

Gowrishankar Chindalore 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: 20070020831
    Abstract: A method of making an array of storage cells includes a first source/drain region underlying a first trench defined in a semiconductor substrate and a second source/drain region underlying a second trench in the substrate. A charge storage stack lines each of the trenches where the charge storage stack includes a layer of discontinuous storage elements (DSEs). A control gate overlies the first trench. The control gate may run perpendicular to the trenches and traverse the first and second trenches. In another implementation, the control gate runs parallel with the trenches. The storage cell may include one or more diffusion regions occupying an upper surface of the substrate between the first and second trenches. The diffusion region may reside between first and second control gates that are parallel to the trenches. Alternatively, a pair of diffusion regions may occur on either side of a control gate that is perpendicular to the trenches.
    Type: Application
    Filed: July 25, 2005
    Publication date: January 25, 2007
    Inventors: Gowrishankar Chindalore, Cheong Hong, Craig Swift
  • Publication number: 20070020840
    Abstract: A storage cell includes a semiconductor substrate defining a trench, a bottom dielectric lining the trench, and a charge storage layer on the bottom dielectric. The charge storage layer includes a plurality of discontinuous storage elements (DSEs). A control gate and a top dielectric cover the DSEs. The storage cell includes a source/drain region underlying the trench. The DSEs may be silicon nanocrystals and the control gate may be polysilicon. The control gate may be recessed below an upper surface of the semiconductor substrate and an upper most of the DSEs may be vertically aligned with the control gate upper surface. The storage cell may include an oxide gap structure laterally aligned with the silicon nanocrystals adjacent the trench sidewall and extending vertically from the upper most of the silicon nanocrystals to the upper surface of the substrate. The DSEs include at least programmable two injection regions.
    Type: Application
    Filed: July 25, 2005
    Publication date: January 25, 2007
    Inventor: Gowrishankar Chindalore
  • Publication number: 20070018232
    Abstract: An array of storage cells include a first source/drain region underlying a first trench defined in a semiconductor substrate and a second source/drain region underlying a second trench in the substrate. A charge storage stack lines each of the trenches where the charge storage stack includes a layer of discontinuous storage elements (DSEs). A control gate overlies the first trench. The control gate may run perpendicular to the trenches and traverse the first and second trenches. In another implementation, the control gate runs parallel with the trenches. The storage cell may include one or more diffusion regions occupying an upper surface of the substrate between the first and second trenches. The diffusion region may reside between first and second control gates that are parallel to the trenches. Alternatively, a pair of diffusion regions may occur on either side of a control gate that is perpendicular to the trenches.
    Type: Application
    Filed: July 25, 2005
    Publication date: January 25, 2007
    Inventors: Gowrishankar Chindalore, Cheong Hong, Craig Swift
  • Publication number: 20070018222
    Abstract: An electronic device can include discontinuous storage elements that lie within a trench. In one embodiment, the electronic device can include a substrate having a trench that includes a wall and a bottom. The electronic device can also include a portion of discontinuous storage elements that lie within the trench. The electronic device can also include a first gate electrode, wherein at least one discontinuous storage element lies along the wall of the trench at an elevation between and upper surface of the first gate electrode and a primary surface of the substrate. The electronic device can also include a second gate electrode overlying the first gate electrode and the primary surface of the substrate. In another embodiment, a conductive line can be electrically connected to one or more rows or columns of memory cells, and another conductive line can be more rows or more columns of memory cells.
    Type: Application
    Filed: July 25, 2005
    Publication date: January 25, 2007
    Applicant: Freescale Semiconductor, Inc.
    Inventors: Michael Sadd, Ko-Min Chang, Gowrishankar Chindalore, Cheong Hong, Craig Swift
  • Publication number: 20070020849
    Abstract: A storage device structure (10) has two bits of storage per control gate (34) and uses source side injection (SSI) to provide lower programming current. A control gate (34) overlies a drain electrode formed by a doped region (22) that is positioned in a semiconductor substrate (12). Two select gates (49 and 50) are implemented with conductive sidewall spacers adjacent to and lateral to the control gate (34). A source doped region (60) is positioned in the semiconductor substrate (12) adjacent to one of the select gates for providing a source of electrons to be injected into a storage layer (42) underlying the control gate. Lower programming results from the SSI method of programming and a compact memory cell size exists.
    Type: Application
    Filed: September 28, 2006
    Publication date: January 25, 2007
    Applicant: Freescale Semiconductor, Inc.
    Inventors: Cheong Hong, Gowrishankar Chindalore
  • Publication number: 20070018216
    Abstract: An electronic device can include discontinuous storage elements that lie within a trench. The electronic device can include a substrate including a trench that includes a wall and a bottom and extends from a primary surface of the substrate. The electronic device can also include discontinuous storage elements, wherein a portion of the discontinuous storage elements lies at least within the trench. The electronic device can further include a first gate electrode, wherein at least a part of the portion of the discontinuous storage elements lies between the first gate electrode and the wall of the trench. The electronic device can still further include a second gate electrode overlying the first gate electrode and the primary surface of the substrate.
    Type: Application
    Filed: July 25, 2005
    Publication date: January 25, 2007
    Applicant: Freescale Semiconductor, Inc.
    Inventors: Gowrishankar Chindalore, Paul Ingersoll, Craig Swift
  • Publication number: 20070018229
    Abstract: An electronic device can include discontinuous storage elements that lie within a trench. In one embodiment, the electronic device can include a substrate that includes a trench extending into a semiconductor material. The trench can include a ledge and a bottom, wherein the bottom lies at a depth deeper than the ledge. The electronic device can include discontinuous storage elements, wherein a trench portion of the discontinuous storage elements lies within the trench. Gate electrodes may lie adjacent to walls of the trench. In a particular embodiment, a portion of a channel region within a memory cell may not be covered by a gate electrode. In another embodiment, a doped region may underlie the ledge and allow for memory cells to be formed at different elevations within the trench. In other embodiment, a process can be used to form the electronic device.
    Type: Application
    Filed: July 25, 2005
    Publication date: January 25, 2007
    Applicant: Freescale Semiconductor, Inc.
    Inventors: Jane Yater, Gowrishankar Chindalore, Cheong Hong
  • Publication number: 20070018221
    Abstract: A semiconductor storage cell includes first and second source/drain regions underlying first and second trenches defined in a semiconductor substrate. Sidewalls of the trenches are lined with a charge storage stack that includes a layer of discontinuous storage elements (DSEs), which are preferably silicon nanocrystals. Spacer control gates are located in the trenches adjacent to the charge storage stacks on the trench sidewalls. The trench depth exceeds the spacer height so that a gap exists between a top of the spacers and the top of the substrate. A continuous select gate layer overlies the first trench. The gap facilitates ballistic programming of the DSEs adjacent to the gap by accelerating electrons traveling substantially perpendicular to the trench sidewalls. The storage cell may employ hot carrier injection programming to program a portion of the DSEs proximal to the source/drain regions.
    Type: Application
    Filed: July 25, 2005
    Publication date: January 25, 2007
    Inventors: Craig Swift, Gowrishankar Chindalore
  • Publication number: 20070004135
    Abstract: A memory charge storage device has regions of sacrificial material overlying a substrate (12). For each memory cell a first doped region (20) and a second doped region (24) are formed within the substrate and on opposite sides of one (16) of the regions of sacrificial material. A discrete charge storage layer (28) overlies the substrate and is between the regions of sacrificial material. In one form a control electrode (34) is formed per memory cell overlying the substrate with an underlying substrate diffusion and laterally adjacent one of the regions of sacrificial material. A third substrate diffusion (60) is positioned between the two control electrodes. In another form two control electrodes are formed per memory cell with a substrate diffusion underlying each control electrode. In both forms a select electrode (64) overlies and is between both of the two control electrodes.
    Type: Application
    Filed: June 29, 2005
    Publication date: January 4, 2007
    Inventor: Gowrishankar Chindalore
  • Patent number: 7157345
    Abstract: A memory charge storage device has regions of sacrificial material overlying a substrate (12). For each memory cell a first doped region (20) and a second doped region (24) are formed within the substrate and on opposite sides of one (16) of the regions of sacrificial material. A discrete charge storage layer (28) overlies the substrate and is between the regions of sacrificial material. In one form a control electrode (34) is formed per memory cell overlying the substrate with an underlying substrate diffusion and laterally adjacent one of the regions of sacrificial material. A third substrate diffusion (60) is positioned between the two control electrodes. In another form two control electrodes are formed per memory cell with a substrate diffusion underlying each control electrode. In both forms a select electrode (64) overlies and is between both of the two control electrodes.
    Type: Grant
    Filed: June 29, 2005
    Date of Patent: January 2, 2007
    Assignee: Freescale Semiconductor, Inc.
    Inventor: Gowrishankar Chindalore
  • Publication number: 20060289946
    Abstract: A semiconductor device includes a memory array having a plurality of non-volatile memory cells. Each non-volatile memory cell of the plurality of non-volatile memory cells has a gate stack. The gate stack includes a control gate and a discrete charge storage layer such as a floating gate. A dummy stack ring is formed around the memory array. An insulating layer is formed over the memory array. The dummy stack ring has a composition and height substantially the same as a composition and height of the gate stack to insure that a CMP of the insulating layer is uniform across the memory array.
    Type: Application
    Filed: June 24, 2005
    Publication date: December 28, 2006
    Inventor: Gowrishankar Chindalore
  • Publication number: 20060194438
    Abstract: A plurality of memory cell devices is formed by using an intermediate dual polysilicon-nitride control electrode stack overlying nanoclusters. The stack includes a first-formed polysilicon-nitride layer and a second-formed polysilicon-containing layer. The second-formed polysilicon-containing layer is removed from areas containing the plurality of memory cells. In one form the second-formed polysilicon-containing layer also contains a nitride portion which is also removed, thereby leaving the first-formed polysilicon-nitride layer for the memory cell devices. In another form the second-formed ploysilicon-containing layer does not contain nitride and a nitride portion of the first-formed polysilicon-nitride layer is also removed. In the latter form a subsequent nitride layer is formed over the remaining polysilicon layer. In both forms a top portion of the device is protected from oxidation, thereby preserving size and quality of underlying nanoclusters.
    Type: Application
    Filed: June 25, 2004
    Publication date: August 31, 2006
    Inventors: Rajesh Rao, Ramachandran Muralidhar, Robert Steimle, Gowrishankar Chindalore
  • Publication number: 20060076609
    Abstract: An electronic device can include an NVM array, wherein portions of word lines are formed within trenches. Insulating features are formed over heavily doped regions within the substrate. In one embodiment, charge storage stacks and a control gate electrode layer can be formed and substantially fill the trench. The insulating features help to reduce capacitive coupling between the heavily doped regions and the control gate electrode layer. In a particular embodiment, the insulating features are recessed from a top surface of a layer outside the trenches. The control gate electrode layer can form a substantially continuous electrical path along the lengths of the word lines. This particular embodiment substantially eliminates the formation of stringers or other residual etching artifacts from the control gate electrode layer within the array. A process can be performed to form the electronic device.
    Type: Application
    Filed: March 14, 2005
    Publication date: April 13, 2006
    Applicant: Freescale Semiconductor, Inc.
    Inventors: Gowrishankar Chindalore, Craig Swift
  • Publication number: 20060079051
    Abstract: Forming a non-volatile memory device includes providing a semiconductor substrate, forming a masking layer having a first plurality of openings overlying the semiconductor substrate, forming diffusion regions in the semiconductor substrate at locations determined by the masking layer, forming a dielectric within the first plurality of openings, removing the masking layer to form a second plurality of openings, forming sacrificial spacers along edges of the second plurality of openings and adjacent to the dielectric, forming a separating dielectric to separate the sacrificial spacers within each of the second plurality of openings, forming a sacrificial protection layer overlying the separating dielectric, removing the sacrificial spacers, removing the sacrificial protection layer, forming at least two memory storage regions within each of the second plurality of openings, and forming a common control electrode overlying the at least two memory storage regions.
    Type: Application
    Filed: October 8, 2004
    Publication date: April 13, 2006
    Inventors: Gowrishankar Chindalore, Jane Yater
  • Publication number: 20060076586
    Abstract: A virtual ground memory array (VGA) is formed by a storage layer over a substrate with a conductive layer over the storage layer. The conductive layer is opened according to a patterned photoresist layer. The openings are implanted to form source/drain lines in the substrate, then filled with a layer of dielectric material. Chemical mechanical polishing (CMP) is then performed until the top of the conductive layer is exposed. This leaves dielectric spacers over the source/drain lines and conductive material between the dielectric spacers. Word lines are then formed over the conductive material and the dielectric spacers. As an alternative, instead of using a conductive layer, a sacrificial layer is used that is removed after the CMP step. After removing the sacrificial portions, the word lines are formed. In both cases, dielectric spacers reduce gate/drain capacitance and the distance from substrate to gate is held constant across the channel.
    Type: Application
    Filed: October 8, 2004
    Publication date: April 13, 2006
    Inventors: Craig Swift, Gowrishankar Chindalore, Laureen Parker
  • Publication number: 20060063327
    Abstract: A floating gate memory cell has a floating gate in which there are two adjacent floating gate layers. The top layer is made to have a contour while leaving the lower layer substantially unchanged. An interlevel dielectric and a control gate follow the contour of the floating gate to increase capacitance between the control gate and the floating gate. The two layers of the floating gate can be polysilicon in which the top layer has the contour formed therein by use of a sacrificial layer. The sacrificial layer is formed over the bottom polysilicon layer and etched. The top polysilicon layer is formed over the sacrificial layer. Subsequent processing of the top polysilicon layer exposes the remaining portion of the sacrificial layer so it can be removed; leaving the contour in the top polysilicon layer for the interlevel dielectric and the control gate.
    Type: Application
    Filed: September 17, 2004
    Publication date: March 23, 2006
    Inventors: Craig Swift, Gowrishankar Chindalore
  • Publication number: 20060063328
    Abstract: A floating gate memory cell has a floating gate in which there are two floating gate layers. The top layer is etched to provide a contour in the top layer while leaving the lower layer unchanged. The control gate follows the contour of the floating gate to increase capacitance therebetween. The two layers of the floating gate can be polysilicon separated by a very thin etch stop layer. This etch stop layer is thick enough to provide an etch stop during a polysilicon etch but preferably thin enough to be electrically transparent. Electrons are able to easily move between the two layers. Thus the etch of the top layer does not extend into the lower layer but the first and second layer have the electrical effect for the purposes of a floating gate of being a continuous conductive layer.
    Type: Application
    Filed: September 17, 2004
    Publication date: March 23, 2006
    Inventors: Gowrishankar Chindalore, Craig Swift
  • Publication number: 20060046406
    Abstract: A non-volatile memory (NVM) has a silicon germanium (SiGe) drain and a silicon carbon (SiC) source. The source being SiC provides for a stress on the channel that improves N channel mobility. The SiC also has a larger bandgap than the substrate, which is silicon. This results in it being more difficult to generate electron/hole pairs by impact ionization. Thus, it can be advantageous to use the SiC region for the drain during a read. The SiGe is used as the drain for programming and erase. The SiGe, having a smaller bandgap than the silicon substrate results in improved programming by generating electron/hole pairs by impact ionization and improved erasing by generating electron hole/pairs by band-to-band tunneling, both at lower voltage levels.
    Type: Application
    Filed: August 31, 2004
    Publication date: March 2, 2006
    Inventors: Gowrishankar Chindalore, James Burnett, Craig Swift, Ramachandran Muralidhar
  • Publication number: 20060043482
    Abstract: A non-volatile memory (NVM) has a silicon germanium (SiGe) drain that is progressively more heavily doped toward the surface of the substrate. The substrate is preferably silicon and the drain is formed by first forming a cavity in the substrate in the drain location. SiGe is epitaxially grown in the cavity with an increasing doping level. Thus, the PN junction between the substrate and the drain is lightly doped on both the P and N side. The drain progressively becomes more heavily doped until the maximum desired doping level is reached, and the remaining portion of the SiGe drain is doped at this maximum desired level. As a further enhancement, the perimeter of the SiGe in the substrate is the same conductivity type as that of the substrate and channel. Thus a portion of the channel is in the SiGe.
    Type: Application
    Filed: August 31, 2004
    Publication date: March 2, 2006
    Inventors: James Burnett, Gowrishankar Chindalore, Craig Swift, Ramachandran Muralidhar
  • Publication number: 20050191808
    Abstract: Nanoclusters are blanket deposited on an integrated circuit and then removed from regions where the nanoclusters are not desired. A sacrificial layer is formed in those regions where the nanoclusters are not desired prior to the blanket deposition. The nanoclusters and the sacrificial layer are then removed. In one form, the sacrificial layer includes a deposited nitride containing or oxide containing layer. Alternatively, the sacrificial layer includes at least one of a pad oxide or a pad nitride layer previously used to form isolation regions in the substrate. Nanocluster devices and non-nanocluster devices may then be integrated onto the same integrated circuit. The use of a sacrificial layer protects underlying layers thereby preventing the degradation of performance of the subsequently formed non-nanocluster devices.
    Type: Application
    Filed: February 26, 2004
    Publication date: September 1, 2005
    Inventors: Robert Steimle, Jane Yater, Gowrishankar Chindalore, Craig Swift, Steven Anderson, Ramachandran Muralidhar